By Dr. Osama Mohammed Samman

Transcription

1 Center for Strategic Health Studies The effect of work posture on developing low back pain, neck pain A cross sectional survey in Damascus, Syria By Dr. Osama Mohammed Samman A Dissertation submitted to the Centre for Strategic Health Studies, Damascus, Syria, in partial fulfillment of the requirements for the award of the Master of Public Health (PH) degree In collaboration with the Liverpool School of tropical Medicine January 2011 Supervised by: Dr. Cor Jonker

2 among dentists i. Declaration I declare that this research is my own unaided work. It is submitted in partial fulfillment of the requirements for the award of the Master of Public Health (PH) degree at Centre for Strategic Health Studies, Damascus Syria in association with Liverpool School of tropical Medicine, Liverpool University, UK. It has not been submitted before for any degree at any other organization. Osama M. Samman January

3 among dentists ii. Executive Summary Introduction: musculoskeletal disorders in dental practice represent a significant issue in the field of occupational health. Prevalence and impact of MSDs have been reported in several studies. Various risk factors have been identified for developing MSDs including physical characteristics of dentist, prolonged static postures, poor positioning, and psychological stress. Musculoskeletal complaints of Syrian dentists have not been established because of lack of epidemiological studies in this field. Aim & objectives: the aim of this study is to prevent musculoskeletal complaints in dental practice through investigating the prevalence of musculoskeletal symptoms among Syrian dentists in Damascus, describing the relation between work postures, physical characteristics of dentists, work environment and musculoskeletal symptoms, analyzing the effect of exercise and education on protection against musculoskeletal symptoms, and identifying the appropriate interventions to help reduce the prevalence of musculoskeletal symptoms. Methods: four hundred dentists were randomly chosen from Damascus dental association to participate in a questionnaire survey. The main questions in the questionnaire included information on general characteristics of dentists, work environment, psychosocial aspects, musculoskeletal complaints during the last year, physical Activities, and knowledge and education about musculoskeletal complaints. A logistic regression analysis was conducted to estimate odds ratios of related risk factors. Results: (67.75%) of dentists (n = 262) responded to the questionnaire. The mean age of participants was (37.66) years. Male dentist represented (73.7%) of participants. (55.6%) of participants were general practitioners. The average of practice years for dentists was (12.56) years, and the mean of daily working hours was (7.63) hours per day. (35.7%) of dentists reported low back pain, (21%) reported shoulder pain, (20.6%) reported neck pain, and (16%) reported hand\wrist pain. Chronic complaints were reported by (34%) of dentists, and (29.1%) of them sought medical care because of musculoskeletal pain. Work absence was reported by (16.1%) of dentists. Musculoskeletal pain influenced daily activities of (15%) of participants. On 100 mm pain scale, (50.2%) of participants reported their pain to be >40. 2

4 among dentists Risk factors for neck pain were awkward back posture, stressful arm positions, working longer hours, gender (female dentists at higher risk), physical work load, and Psychological factors. Risk factors for Low back pain were sitting posture, height, and Psychological factors. Risk factors for shoulder pain were stressful arm positions, age, gender (female dentists at higher risk), working longer hours, physical work load, and Psychological factors. Risk factors for hand\wrist pain: were stressful arm positions, age, gender (female dentists at higher risk), practice years, and Psychological factors. Preventive factors for: neck pain: were age and exercise. Low back pain: was standing posture. Shoulder pain: was height. Hand\wrist pain: were sitting posture and height. Conclusion: The present study confirms previous findings of research and contributes additional evidence that musculoskeletal disorders represent a serious health and occupational concern in modern dental practice. For the Syrian context, this research will serve as a base for more future studies to establish the relation between studied risk factors and developing musculoskeletal complaints. Further research is essential to better understand the role and mechanism of psychological risk factors in developing MSDs. Recommendations: Prevention against musculoskeletal disorders may represent the key element for Syrian dentists to safely practice dentistry and to avoid disability and early retirement, as well as for government to preserve important human and financial assets in a time of scarcity of resources. Developing Safety legislation, dissemination of preventive education and guidelines, management of MSDs, promoting physical activity, improving surveillance and reporting, and fostering research are recommended to prevent the development of M SDs in dental practice. The word count for the abstract is (592) words, and for the dissertation is (11432). 3

5 among dentists This work is dedicated to my newborn child Ammar May god bless him! 4

6 among dentists iii. Acknowledgements I would like to express my sincere gratitude To all dentists who responded for their constructive participation in this study. To employee, colleagues, and board of study at Centre for Strategic Health Studies for their corporation. To all experts, doctors, and convenors at Liverpool School of Tropical Medicine for their support, advice and encouragement. I would specially like to thank my first supervisor Dr. Cor Joncer and methods supervisor Dr. Gamal Mohammed for providing me advice and support though out the dissertation. I would like to express my sincere thanks to all those who helped with data collection especially Dr. Muna Alkurdy, Dr. Ahmad Alhallak, Dr Abdoul Rahman Azien, and Nashawy bros. I would like to express my heartfelt thanks to my wife Jehan Alnoufi who has been with me all the way understanding, encouraging, and sharing the sacrifice of attaining this master degree. And finally, no matter what I do to thank them, I can never pay back my parents even the smallest portion of their support and care for me through my life. 5

7 among dentists iv. Table of Contents i.declaration...1 ii. Executive summery...2 iii. Acknowledgements...5 iv. Table of Contents...6 v. List of Figures...9 vi. List of Tables vii. List of Appendices...11 Chapter 1: Introduction Anatomy and physiology of the spine Definition of Posture History of Posture in Dental practice Sitting posture in dental practice Importance of the study Aim and objectives Chapter 2: Literature review Definition of musculoskeletal disorders Prevalence of musculoskeletal disorders in dentistry The burden of musculoskeletal disorders Mechanisms leading to musculoskeletal disorders in dentistry Risk factors for musculoskeletal disorders in dentistry Personal characteristics of the dentist Age Gender Height and weight....25

8 among dentists Work environment Years of dental practice Working long hours Psychological stress Conclusion 28 Chapter 3: Study design and methods Study design Study population Sampling Data collection and administration of instruments Data analysis..32 Chapter 4: Results Basic Characteristics of participants Prevalence of musculoskeletal complaints Pain severity Presence of risk factors The association between risk factors and musculoskeletal pain Standing and sitting posture Awkward back posture and stressful arm positions Personal characteristics of dentists Risk factors in work environment Exercise Knowledge and education Multivariate analysis Neck pain. 42 7

9 among dentists Low back pain Shoulder pain Hand\wrist pain 43 Chapter5: Discussion The main results Prevalence of musculoskeletal complaints Musculoskeletal consequences Association with risk factors Interventions to reduce musculoskeletal complaints in dentistry Education Exercise Study limitations and the need for further research..58 Chapter6: conclusions and recommendations Conclusions Recommendations Safety legislation Preventive education Preventive guidelines Promoting physical activity Management of MSDs Surveillance and reporting Research...61 Chapter 7: references..62 Chapter 8: Appendices 70 8

10 among dentists v. List of Figures Figure 1.1: the five regions of the spinal column Figure 1.2: muscles that connect the upper extremity to the spine.. 14 Figure 2.1: flowchart showing how prolonged static postures can progress to pain or a musculoskeletal disorder 23 Figure 3.1: calculation of sample size in EPI INFO Version Figure 4.1 age distribution of participants. 35 Figure 4.2 participants distributed by educational degree.35 9

11 among dentists vi. List of Tables Table 2.1: musculoskeletal disorders prevalence rates by body site, country, and year of publication..19 Table 4.1: basic characteristics of participating dentists in the study stratified by Gender.36 Table 4.2: prevalence of musculoskeletal complaints and their consequences among dentists 37 Table 4.3: severity rating of pain cross tabulated by sex and musculoskeletal Consequences.38 Table 4.4: presence of risk factors 39 Table 4.5 univariate association between neck pain and risk factors.44 Table 4.6 univariate association between low back pain and risk factors Table 4.7 univariate association between shoulder pain and risk factors...46 Table 4.8 univariate association between hand\wrist pain and risk factors..47 Table 4.9 multivariate analysis of risk factors for neck pain.48 Table 4.10 multivariate analysis of risk factors for low back pain.48 Table 4.11 multivariate analysis of risk factors for shoulder pain. 49 Table 4.12 multivariate analysis of risk factors for hand\wrist pain

12 among dentists vii. List of Appendices Appendix1: abbreviations used in this document 70 Appendix2: budget summery.. 71 Appendix3: timetable for the research project Appendix4: participation information sheet..73 Appendix5: participation information sheet (Arabic translation)..74 Appendix6: Questionnaire for Information about developing pain in different body parts dentists related to dental practice...75 Appendix7: Questionnaire for Information about developing pain in different body parts related to dental practice. (Arabic translation)...83 Appendix8: Examples for Chairside stretching exercises.90 Appendix9: Ergonomic guidelines in dental practice Appendix10: Some photos of dentists in working postures

13 among dentists Chapter 1 Introduction Musculoskeletal disorders have recently been increasing causing numerous health and financial consequences (Alexopoulos et al., 2004, p. 1). Various risk factors such as prolonged static postures, poor positioning, psychological stress and physical characteristics of dentist have been identified for the development of musculoskeletal disorders in dental practice (Valachi and Valachi, 2003a, p. 1345) Anatomy and physiology of the spine The vertebral column provides the main support for the body in maintenance of posture while standing, sitting, bending or twisting, so it is important to have an overview on the anatomy of the vertebral column and recognize the function of the supporting muscles of the vertebrae (Mayfield clinic, 2010). The spine consists of 33 vertebrae and is divided into four areas: 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 fused sacral vertebrae and 4 fused coccyx vertebrae. The thoracic spine protects the organs of the chest; while the main role of the lumbar spine is to bear the weight of the body (ibid.).figure 1.1 illustrates the five regions of the spinal column. 12

14 among dentists Figure 1.1 the five regions of the spinal column. Adopted from (Mayfield clinic, 2010). Every vertebra has three functional parts: Anterior drum-shaped body (to pear weight and compression), posterior arch-shaped bone (to protect the spinal cord) and posterior star-shaped processes (for muscle attachment). In a side view of the vertebral column, four explicit curves forming an S-shape are noticed. Cervical and lumber regions with a slight posteriorly concave curvature (Lordotic Curves), while the thoracic and sacral regions have a mild posteriorly convex curvature (Kyphotic Curves). The vertebrae are separated by pads of fibro-cartilage called intervertebral discs. The major function of these discs is to act as shock absorbers of applied forces and compressions on the spine and provide it with flexibility (Mayfield clinic, 2010).The nutrition of the discs is provided by diffusion of the nutrients such as oxygen, glucose, and sulphate. These nutrients reach the discs through the surrounding blood vessels and capillary plexus beneath them (Maroudas et al., 1975, p. 113). A group of five muscles connect the upper extremity to the spine. They are Trapezius, Rhomboideus major, Latissimus dorsi, Rhomboideus minor and Levator scapulae (bartleby.com, 2010).The main two muscles which contribute holding the spine are: 13

15 among dentists The trapezius which is a triangular, flat muscle covering the upper and back part of the neck and shoulders. The angles of the trapezius fibers provide tension in three directions: up, down, and to the central line of the body. The other muscle is the Latissimus dorsi which is also a triangular, flat muscle covering the lumbar region and the lower half of the thoracic region as illustrated in Figure 1.2 (ibid.). Trapezius Latissimus dorsi Figure1.2 muscles that connect the upper extremity to the spine Adopted from (bartleby.com, 2010) 1.2. Definition of Posture Posture is the position in which to hold the body upright against gravity while standing, sitting, or lying down. Good posture involves training the body to stand, walk, sit and lie in positions where the least strain is placed on supporting muscles and ligaments during movement or weight-bearing activities (Mayfield clinic, 2009a, p. 1). 14

16 among dentists 1.3. History of Posture in Dental practice Until the first dental chair was created by James Snell in 1832; both patient and dentist stood during dental treatment (Wilwerding, 2001, p. 19). In the first half of the 20th century dentists continued working standing during the practice of dentistry, but by the early 1960 s, with the emergence of new concepts in dental practice and the development of modern dental units with motorised backs that allowed patients to lie back facilitating better access to the patient s mouth, dentists began to increasingly realize that working in a sitting posture was healthier for them, and the use of dental stool became more popular in dental practice (Glenner, 2000). Dentists also began to recognize and apply the concept of four handed dentistry (a technique in which a dental assistant works directly with the dentist on the procedures being done in the mouth of a patient) (Leon, 1981, p. 781) which was presented by researchers through clinical studies. The concept is based on the fact that when a team of highly trained individuals work together in an organized work environment; the efficiency and productivity of dental treatment will be increased and the quality of care for patients will be improved along with preserving physical well-being of the team (webnetint.com, 2000) Sitting posture in dental practice The major shift of posture in dental practice from standing to sitting in the 1960 s was reasoned by the results of different studies which showed that sitting posture reduced the static workload of muscles required to maintain the joints of the spine, hip, knee and foot(pottier et al. 1969). As well sitting posture provides more stability (Nachemson, 1966, p. 107) which may help the dentist performing accurate and precise hand tasks and better control for foot operations. More recent studies found that for sitting posture the spinal load is lower than for standing. Althoffm et al. (1992) found an increase in body height measurement while sitting compared to the height while standing. However, the loads on the facet joints and on the ligaments may be high for sitting posture and intersegmental movements is reduced which may affect the nutrition of the disc (Rohlmann et al p. 791). Sitting for extended periods of time in poor posture and without prober mobility may lead to the development of musculoskeletal symptoms (lower back pain) due to ligaments strain in the back and stretching of back muscles (McGill & Brown, 1992). Slouched 15

17 among dentists sitting posture also causes substantial increase in disc pressure which may lead to pack pain (Black, McClure, & Polansky, 1996) Importance of the study Prevalence and risk factors of musculoskeletal disorders for Syrian dentists have not been established because of lack of data and related studies. It is essential to establish epidemiological evidence about the dominant risk factors associated with the development of this occupational health problem in Syria, the health impact on dental practitioners including limited functioning and disability, and the economic burden of this health issue including cost of treatment and sickness absence. It is also crucial to investigate whether the Syrian status of dental practice and risk factors are consistent with the established risk factors of developing musculoskeletal symptoms for dentists in the literature. This study is trying to investigate work posture in dental practice for Syrian dentists and other supposed risk factors in relation to developing musculoskeletal complaints in different body parts especially neck and low back Aim and objectives Aim To prevent musculoskeletal complaints in dental practice Objectives 1. To investigate the prevalence of musculoskeletal symptoms among Syrian dentists in Damascus. 2. To describe the relation between work postures, physical characteristics of dentists, work environment and musculoskeletal symptoms. 3. To analyze the effect of exercise and education on protection against musculoskeletal symptoms. 4. To identify the appropriate interventions to help reduce the prevalence of musculoskeletal symptoms. 16

18 among dentists Chapter 2 Literature review 2.1. Definition of musculoskeletal disorders Musculoskeletal disorders (MSD) are injuries to the human support system of muscles, ligaments, tendons, nerves, blood vessels, bones and joints, and can occur from a single event or cumulative trauma, MSD can cause pain in the neck, shoulder, arm, wrist, hands, upper and lower back, hips, knees and feet (Graham, 2002) Prevalence of musculoskeletal disorders in dentistry The significance of musculoskeletal disorders (MSDs) in general and particularly in dental profession has led to numerous studies - as discussed below to investigate the prevalence of MSDs and identify risk factors and proper interventions to reduce the burden of MSDs. The prevalence of musculoskeletal complaints is high and well documented in the literature (table 2.1) (Alexopoulos et al , Fish et al. 1998, Rising et al , Szymanska 2001, Szymanska 2002, Valachi and Valachi a, Hayes et al , Finsen et al. 1998, AlWazzan et al. 2001, Chowanadisai et al ). Many studies as discussed below report high prevalence of musculoskeletal pain. The most significant musculoskeletal problem with highest prevalence was found to be lower back pain (Puriene et al., 2007, p. 11). A cross-sectional study by Szymanska in Poland targeted 268 dentists (89.2% were women and 10.8% were men) and found that 60.1% of dentists had musculoskeletal problems in the thoracic lumbar region (Szymanska, 2002, p. 170). Similar results for low back pain at 59%were found by Finsen et al. (1998, p. 122) in a study based on questionnaires to 99 dentists (56 males and 43 females) in addition to observation of 8 female dentists. 53.7% of 285 surveyed Dentists (73.3% males and 26.7% females) in Queensland were found to experience lower back pain (Leggat and Smith, 2006, p. 324). In Greece; another cross-sectional study based on self reported questionnaire from 430 dentists (231 men and 199 women) showed that 46% of dentists had lower back pain (Alexopoulos et al., 2004, p. 4). However, AlWazzan et al reported only 36.3% of 91dentists (53 men and 38 women) in Saudi Arabia as having regular back pain (AlWazzan et al., 17

19 among dentists 2001, p. 5). Leggat and Smith (2006, p. 325) reported that neck pain in Queensland, Australia was a prevalent musculoskeletal complaint at 57.5%. Dentists in Poland were found to have comparable neck pain complaints at 56.3% (Szymanska, 2002, p. 170). However,Greek dentists were reported to have 26% neck pain prevalence (Alexopoulos et al., 2004, p. 4). Similarly neck pain prevalence for dentists in Saudi Arabia was about 20% (AlWazzan et al. 2001, p. 5). Shoulder pain was also reported as a musculoskeletal complaint. Queensland study found that 53% of dentist suffered shoulder pain (Leggat and Smith, 2006, p. 325). Another study in Netherlands reported that 52% of dentists had shoulder pain (Droeze and Jonsson 2005, cited in Hayes et al ). While in Greece only 20% of dentists were reported to experience shoulder pain (Alexopoulos et al., 2004, p. 4). Some studies have combined neck and shoulder pain and reported higher prevalence of musculoskeletal complaints. A Swedish study reported very high prevalence of shoulder and neck pain among female dentists at 85% (Akesson et al. 1999, cited in Hayes et al -2009). The Greek study reported 30% prevalence of combined neck and shoulder complaints (Alexopoulos et al., 2004, p. 4). In Denmark; Finsen et al. (1998, p. 122) reported neck and shoulder troubles at 65%. Several studies reported general prevalence of musculoskeletal complaints among dentist. A study of the occupational health problems in Thailand reported that 78% of dentists had musculoskeletal complaints (Chowanadisai et al. 2000, cited in Hayes et al -2009). In the Greek study the prevalence of all musculoskeletal complaints was found 70% (Alexopoulos et al., 2004, p. 4). Another cross-sectional study in New South Wales, Australia found that 64% of 355 dentists (86% men and 14% women) had suffered musculoskeletal pain in the previous month (Marshall et al. 1997, p. 241). The majority of the previous studies rated the prevalence of MSDs as high. This ranking would have been much more accurate if compared with other groups in the population such as physicians, health and dental assistants, or even with the entire population as a reference group. A comparison by Finsen et al. (1998) between dentists and general wage earners (with similar age) in Denmark regarding musculoskeletal complaints revealed that dentists had more one year prevalence of MSDs. Such comparisons may reflect a closer representation of reality. Although the cross- sectional design of the previous studies provided good estimates of MSDs prevalence, yet, it lacked the ability to explain the prevalence variation within these studies. 18

20 among dentists Table 2.1 Musculoskeletal disorders (MSDs) prevalence rates by body site, country, and year of publication. Based on (Hayes et al, 2009) Body site MSD prevalence (%) Country Reference Back 54 (lower back) Australia 46 (lower back) Greece Leggat and Smith, 2006 Alexopoulos et al., Poland Szymanska, Saudi Arabia AlWazzan et al., (lower back) Denmark Finsen et al., 1998 Neck 57 Australia 26 Greece Leggat and Smith, 2006 Alexopoulos et al., Saudi Arabia AlWazzan et al., Poland Szymanska, 2002 Shoulder 53 Australia 52 Netherlands 20 Greece Leggat and Smith, 2006 Droeze and Jonsson, 2005 * Alexopoulos et al., 2004 Neck shoulder Any * cited in Hayes et al., Sweden Akesson et al., 1999 * 65 Denmark Finsen et al., Greece 78 Thailand Alexopoulos et al., 2004 Chowanadisai et al., 2000* 64 Australia Marshall et al., Greece Alexopoulos et al.,

21 among dentists 2.3. The burden of musculoskeletal disorders The annual incidence of MSDs represented 31% of all occupational diseases estimated in the world in 1994 (WHO, 2003). This figure indicates that MSDs are the most frequent occupational disease affecting workers throughout the world (Leigh et al., 1999).The total costs of musculoskeletal disorders in society are calculated by computing both direct and in direct costs (Piedrahita, 2006, p. 380).Direct costs (health care costs) involve hospital care, drug and physicians costs, rehabilitation, medical equipment, and other health services. While indirect costs include productivity losses for worker and employer, work absenteeism, and workers compensation by health insurance (Piedrahita, 2006, p. 381). However the degree of musculoskeletal disorders burden is dependent upon the severity of the case, the quality of health care delivery, work environment, patient characteristics (age, sex, and general health status) and socioeconomic factors (Baldwin 2004, cited in Piedrahita, 2006). In dentistry several studies reported the health impact of musculoskeletal disorders. In Greece Alexopoulos et al. (2004, p. 1) found that medical care seeking was 32% and work absenteeism particularly for chronic back pain was 16%. They also found that the comorbidity of chronic complaints was highly linked to increased cost of musculoskeletal disorders (Alexopoulos et al., 2004, p. 8). Queensland, Australia study reported that 37.5% of dentists had sought medical care in the previous year and 9.1% of dentists took sick leave because of musculoskeletal disorders. The mean time taken was 11.5 days (Leggat and Smith, 2006, p. 324). In Saudi Arabia, AlWazzan et al. (2001, p. 7) reported that 21.6% of dentists missed work because of neck pain and 24.7% missed work due to back pain. They also reported that 25.3% and 37.3% of dentists sought medical care for neck and back pain respectively. These figures demonstrate the reasonably huge burden of MSDs in dental practice. However, economic evaluation for direct and indirect financial costs of MSDs in dental practice along with epidemiological investigation would provide more comprehensive perspective for the actual burden of MSDs Mechanisms leading to musculoskeletal disorders in dentistry The posture of dentists body should be maintained neutral and balanced during dental treatment. Unfortunately, despite the availability of ergonomic dental equipment, dentists experience inconvenient working postures including forward bending and repeated twisting of head, neck and 20

22 among dentists trunk to the direction of patient to gain better visibility during treatment (Valachi and Valachi, 2003a, p. 1347). The stressed muscles (which are responsible for rotating the body to the treatment side) become stronger and shorter and as a result can become ischemic and painful leading to neck, low back strain. While the opposing muscles become weaker and elongated leading to misalignment of the spinal column and decreased range of motion in the opposite direction of the treatment (Rundcrantz et al , cited in Valachi and Valachi, 2003a). In standing postures, the spine has four natural curves as mentioned when viewed from the side: cervical and lumbar lordosis, thoracic and sacral kyphosis (Figure 1.1) (Mayfield clinic, 2010). The curves are interdependent, any change in one curve will result in a change in the upper and lower curves. (Norkin and Levangi- 1992, cited in Valachi and Valachi, 2003b). The curves especially the lumbar and cervical curves have more ability to be mobile and can be more easily affected by different postures. In a posture when the natural curvature of the spinal curves is maintained; the curves are balanced against the center of gravity, the main support of the spine in this posture is provided by the bony vertebral structure where the vertebrae are resting on one another. These curves can sometimes be exposed to either exaggeration or flatness, in such situation; the spine support to keep the body straight is increasingly dependent on muscles, ligaments, and soft tissue (Valachi and Valachi, 2003b, p. 1605). In an unsupported sitting posture in dentistry the lumbar lordosis flattens. The vertebral support of the spine decreases; increasing the muscular support of the spine (reinforced by ligaments and connective tissue at the back of the spine) which causes tension in these structures (ibid.). The frequent flattening of the lumbar curve also causes the migration of nucleus in the spinal disk posteriorly towards the spinal cord. With time, pressure on the posterior wall of the disk increases making it weaker and may result in herniation of the disk (ibid.). In order to acquire better visibility during dental treatment, dentists tend to hold their head and neck in an irregular forward posture. This poor posture is prevalent where the weight of the head is maintained through continuous contraction of the cervical and upper thoracic spinal muscles and the supporting role of the vertebrae is seriously minimized (Hertling and Kessler, 1996). The result is often tension and pain in the neck. The pain may be accompanied with headache, interscapular muscles and shoulders pain and it may become chronic. Sometimes the pain can spread out to the arms. Disk herniation or degeneration may result due to continuously contracted cervical muscles and weakened spinal disks (Cailliet 1991, cited in 21

23 among dentists Valachi and Valachi, 2003b).The Mechanism of developing pain and musculoskeletal disorder due to prolonged static postures is illustrated in figure

24 among dentists Prolonged Static Posture Muscle Fatigue Muscle Imbalance Muscle Ischemia/Necrosis Trigger Points and Muscle Substitution Pain Protective Muscle Contraction Joint Hypomobility Nerve Compression Spinal Disk Degeneration/ Herniation Musculoskeletal Disorder Figure 2.1 Flowchart showing how prolonged static postures can progress to pain or a musculoskeletal disorder. (Adapted from Valachi and Valachi, 2003a, p. 1346) 23

25 among dentists 2.5. Risk factors for musculoskeletal disorders in dentistry Triggering the spark of musculoskeletal disorders in dentistry is usually attributed by a complex combination of multiple risk factors (Valachi and Valachi, 2003a, p. 1345). Personal characteristics of the dentist including age, sex, weight and height in addition to work environment conditions such as prolonged static postures, working long hours, duration of dental practice, and psychological stress (High job demand and lack of control over work) all represent the main risk factors attributing to the development of MSDs. It is not easy to set a single risk factor as a causative factor for developing musculoskeletal disorders separated from other possible risk factors (Hayes et al., 2009, p. 163). For instance high exposure to physical and psychosocial risk factors at work is likely to increase the symptoms of musculoskeletal disorders compared to exposure to either physical or psychosocial risk factors (Devereux et al., 2002, p. 269) Personal characteristics of the dentist Physical and psychological characteristics of dentists do not initiate MSDs on their own, but only when combined with work related risk factors, they can increase the possibility of developing MSDs. The following are the main characteristics of dentist involved with increased risk of MSDs Age As people age, mass and density of the bone gradually decrease due to loss of calcium and other minerals in the bone. Fluid in the joints may decrease making them less flexible. The muscle fibers shrink, and lost muscle tissue may be replaced with a tough fibrous tissue reducing the ability of muscles to contract (National Institutes of Health, 2010).The prevalence of MSDs was found to increase with age. Zwart, et al. (1997, p. 793) analyzed the difference in prevalence of musculoskeletal complaints from two surveys with an interval of around four years for employees in heavy physical work (cases) and mental work (controls) and found that there were significantly greater increases in prevalence of musculoskeletal complaints (especially for neck and back) in the exposed group compared with the control group over the follow up interval. This study indicates that age seniority in addition to exposure to work related physical load may increase the risk of developing MSDs. Alexopoulos et al. found that chronic musculoskeletal complaints for dentists significantly increased with age after 50 years. Age was a significant risk factor only for developing neck pain, and aging was mildly associated with medical care seeking (Alexopoulos et al., 2004, p. 24

26 among dentists 7). Other studies however, reported decrease in the prevalence of MSDs (neck pain) with age (Finsen et al. 1998, p. 124). They justified their findings by the possibility of dropping out of dentistry among the older dentists. This argument might be limited by contrasting simple physiological facts about aging of human body, and may be attributed to heavily relying on statistical analysis in a study design that does not take time into consideration Gender The sex differences in musculoskeletal pain have been clinically and experimentally established in several studies. Rollman and Lautenbacher (2001, p. 20) reported that women are more sensitive, have more musculoskeletal problems than men and they are more susceptible to the development of musculoskeletal pain problems. In dentistry female dentists are at higher risk of developing occupational MSDs due to their inherent gender differences (valachi, 2008a, p. 127). Women dentists experience higher prevalence of chronic musculoskeletal pain and higher pain frequency and severity than male dentists due to hormonal and reproductive factors and estrogen level (Wijnhoven et al., 2006). Muscles force exertion in women equals only two-thirds of the men s, therefore in dental practice when awkward postures are assumed; female dentists have less muscle to balance their bodies (Kroemer et al 1997, cited in valachi 2008a). During pregnancy women are more susceptible to musculoskeletal complaints due the physiological changes including laxity in spinal joints and ligaments and modified body posture in which the center of gravity is shifted forward increasing the load on muscles (Occupational Health Clinics for Ontario Workers Inc, 1996). These studies may explain why female dentists experience higher pain severity and why they rate their pain at the highest rank as mentioned by several studies (Chowanadisai et al. 2000, cited in Hayes et al -2009, Marshall et al. 1997) Height and weight Overweight has been reported to be a risk factor for developing MSDs in lower back. A four year follow-up study based on magnetic resonance imaging (MRI) found that overweight was a significant risk factor of lumbar disc degeneration especially at younger age in the mid twenties (Liuke et al., 2005, p. 903). Overweight was also associated with median mononeuropathy. Hamann et al. (2001, p. 167) stated that dentists who developed median mononeuropathy were more likely over weighted with higher BMI values. However, some studies found that neck and 25

27 among dentists back pain were lightly affected by weight (AlWazzan et al., 2001, p. 7). As regards to the effect of height in relation to MSDs, tall men were found more susceptible to low back problems. A crosssectional study in Britain investigated the relation of low back pain to height in general population and found that the risk of low back pain had increased only among men (Walsh et al., 1991, p. 420). Alexopoulos et al. (2004, p. 5) mentioned that height was a significant risk factor for developing hand/wrist complaints. The link with weight and height as risks for developing MSDs is inconsistent and lacks rigorous evidence. Establishing this association might be enhanced through systematic evaluation of related studies Work environment Years of dental practice There has been contrast in the results of different studies in regards to the effect of years spent in dental practice and the development of MSDs. Some studies reported negative association between the prevalence of MSDs and years of dental practice, and dentists with fewer years of dental experience were significantly more likely to report musculoskeletal pain (Chowanadisai et al , cited in Hayes et al , Leggat and Smith 2006, Finsen et al. 1998). Other studies, however, found that dentists who had less than five years in dental practice were asymptomatic for MSDs, and the more years dentists spend in dental practice, the more they are likely to experience different MSDs (Szymanska, 2002). According to Hayes et al., this discrepancy might be explained by assuming that dentists with more experience have developed certain work postures to avoid musculoskeletal conditions, or simply because that dentists with severe musculoskeletal symptoms are not working any more (Hayes et al., 2009 p. 164) working long hours All reviewed studies agreed that working long hours in dental practice is a significant risk factor for developing MSDs. The study of New South Wales stated that dentists who adopted fourhanded dentistry worked more hours without a break and experienced significantly higher musculoskeletal pain (Marshall et al., 1997, p. 242). Finsen et al. (1998, p. 121) reported an association between the duration of patient treatment and neck/ shoulder pain. An association between working longer hours and higher demand for recovery was stated by Alexopoulos et al. (2004, p. 4). The 26

28 among dentists prevalence of back pain In Saudi Arabia increased when they worked more weekly hours (AlWazzan et al., 2001, p. 7) Psychological stress The effects of stress on human performance have widely been studied in the course of cognitive psychology (Bourne and Yaroush, 2003, p. 9). Constant relation between continues exposure to stressors and development of health effects has been established in the literature years ago (Cohen, 1980, p. 82). Psychosocial factors at work like high job demands, lack of control and lack of social support at work were found to be associated with musculoskeletal disorders (Bongers et al., 1993). However, recent studies suggested that the association between psychosocial work characteristics and MSDs is derived with confounding by the effect of physical factors at work (Hoogendoorn, et al., 2001, p. 258). Dentists general and musculoskeletal health was found to be related to their psychological status at work (Puriene et al, 2007, p. 13). Several factors may contribute to the psychological load in dental practice. Dentists reported that dentistry is a stressful profession, especially in the presence of heavy work load, low job control and practice management issues ( late schedule and causing pain to patients) (Moore and Brodsgaard 2001, cited in Puriene et al, 2007). Some studies have investigated the association between psychological factors in dental practice and musculoskeletal outcome for dentists and found significant links. Alexopoulos et al. (2004, p. 5) found a significant link between low job control and neck pain and Hand/wrist pain. However, low job control was inversely related to the dentist s age and duration of employment. They also revealed that high job demands and perceived exertion increased sickness absence and the need for medical care due to low back pain (Alexopoulos et al, 2004, p. 7). Dentists working under workload pressure were more anxious, less satisfied with their career and vulnerable to developing MSDs (Rundcrantz et al 1991, cited in Puriene et al 2007). As a result, theses studies indicated an association between personal and work related psychosocial status (with or without the effect of physical factors) and between developing musculoskeletal symptoms for dentists. Yet, solid evidence to derive cause and effect relation is still required. 27

29 among dentists 2.6. Conclusion All the preceding studies agreed that musculoskeletal disorders represent a serious health and economic burden for dentistry. However, these studies had remarkable differences regarding the prevalence of MSDs. An important question emerges here about the reason behind the prevalence differences in different countries. One possible answer might be the variation in risk factors which dentists are exposed to in each country. For example daily or weekly working hours vary among different countries and between private and public sector within each country. Some countries especially developed countries have regulations to limit maximum working hours per week. However if the majority of dentists work for private sector or individually; these regulations will have minimum effect on reducing working hours. Thus the local structure of dental profession in each country may have an important impact on distribution and prevalence of MSDs among dentists who work long hours in this country. Another variation among counties is the availability of ergonomic dental equipment and ergonomic training principles for dentists to avoid development of MSDs. The development of MSDs was associated with both physical and psychological status of the dentist as mentioned earlier, and countries are diverse in the level of socio-economic development. This variation will have impact on dentists as well as other professions. Dentists who need to improve their socio-economic status will be subjected to more psychological stress and thus are more susceptible to development of MSDs. These variations along with the design and methods used in each study (including sampling and sample size differences, differences in age categories, male/female ratio within the sample and variation in results inference) may provide a reasonable explanation of the variation of MSDs prevalence in different countries. 28

30 among dentists Chapter 3 Study design and methods 3.1. Study design The hypothesis of this research is that there is an association between awkward static work posture and the development of musculoskeletal symptoms in dental practice. In order to locally test this hypothesis and answer the research question which is: Are the risk factors of developing musculoskeletal symptoms in dental practice in Syria consistent with the well known risk factors in the literature? And if not why would they be different? It is essential to investigate the prevalence of musculoskeletal symptoms among Syrian dentists and related local risk factors. The best study design to determine the prevalence and answer research question is a cross sectional study (Olsen and St. George, 2004). This design is also useful to derive associations between MSDs and related risk factors (Mann, 2003, p. 56). Other study designs were used to establish the causality between different postures in dental practice and developing MSDs. Observational studies including video recording in three dimensions (using two cameras at the same time in different angles) and muscle activity registry using electromyography (EMG) were conducted in several countries (Finsen et al., 1998, p. 120). However, despite the evidence these studies provide, they are locally complex to conduct, expensive and time consuming. Cross-sectional study design is used to describe a certain population in regards to a defined outcome and related risk factors, to detect the prevalence of an outcome at a certain time point and to investigate supposed association between risk factors and an outcome (Levin, 2006, p. 24). Cross-sectional studies are fairly inexpensive and can be conducted in little time (which in extremely important in this research), but only provide a snapshot of the current situation and lack the strength to derive causality between exposure and outcome (Levin, 2006, p. 25). Based on the preceding discussion and the requirement of this research, a cross sectional design was selected to conduct the study Study Population The target population of this study was working dentists in Syria (about 15000) represented by dentists registered in Damascus dental association, assuming that dental practice in Damascus is 29

31 among dentists similar to every other Syrian governorate. There were 2793 working dentists included in the registry of Damascus dental association (last updated ) Sampling A simple probability-based sample was chosen from dental registry.the sample size was calculated at confidence level 95% using (EPI-INFO, V , Statcalc V 6) (CDC, 2010) according to the population of all Syrian dentists and was (262). The expected frequency was about 50% based on previous studies (Alexopoulos et al., 2004 & Szymanska, 2002), the worst acceptable value was 56% (±6%) as illustrated in figure 3.1. Only working dentists for more than one year without cessation have been accepted in the study. EpiInfo Version 6 Statcalc November 1993 Population Survey or Descriptive Study Using Random (Not Cluster) Sampling Population Size : Expected Frequency: % Worst Acceptable : % Confidence level sample size 80% % % % % 716 Figure 3.1: calculation of sample size in EPI INFO Version

32 among dentists 3.4. Data Collection and Administration of Instruments Data collection started after obtaining Ethical approval from the Ministry of Health. The data was collected by means of questionnaire which is a typical data collection tool for crosssectional studies. Self reported questionnaires are carried out in less time and expenses compared to interviews. However, larger sample size is required and low responding rate is expected (Mann, 2003, p. 56). Based on the mechanical association between prolonged static postures in dental practice and other risk factors and between MSDs, in addition to the psychosocial association between stress and MSDs as explained in literature review, a self reported questionnaire has been developed to inquire the prevalence of MSDs among Syrian dentists and derive associations between the mentioned risk factors and MSDs. Some questions in the questionnaire were quoted from the Nordic Musculoskeletal Questionnaire which is a standardized questionnaire for low back, neck, shoulder and general complaints for use in epidemiological studies, it was developed by the Nordic Council of Ministers (Kuorinka, et al., 1987). The questionnaire was distributed to (5) colleagues in to acquire face validity then after adjustment, this questionnaire was piloted to (6) dentists to make sure that the language of the questions was clear and the answers have the necessary variation for analysis. The final version of the questionnaire was distributed to the main sample of dentists in their clinics with the help of pharmaceutical representatives. Data collection began on ( ). (400) questionnaires were distributed to dentists clinics, but within the period of (5) weeks and repeated visits to dentists, only (241) questionnaires were answered. (9) Of these questionnaires were excluded because dentists did not complete full year of dental practice. (30) Dentists out of those who did not respond to the questionnaires accepted to be questioned by phone. Data collection was completed by ( ) with response rate at (67.75%). The questionnaire was divided to 7 main categories: General information of the respondents including questions on age, gender, anthropometry, educational degree, marital status, and duration of employment. General health including questions on perceived health status by respondents and the existence of chronic diseases. 31

33 among dentists Work environment including questions on working with an assistant, presumed work posture, perceived physical effort for the job, working time during the day, working hours without a break, number of breaks during a working day, and the total working hours per day. Psychosocial aspects including questions on perceived job demands and work control. Symptoms including questions on occurrence of musculoskeletal complaints during the last year, chronicity of musculoskeletal complaints, impairment, work leave and medical care seeking due to musculoskeletal complaints, perceived pain scale(dentists where asked to rate the severity of their pain on a 100 mm visual pain scale). Physical Activities including questions on exercise practice, frequency and duration of exercise, type of exercise. Knowledge and education including questions on perceived risk and preventive factors of MSDs, attending educating courses on ergonomics and management of MSDs. A four-point scale was used with ratings Never, Sometimes, Often and Always for most variables. While a two-point scale was used with ratings Yes and No for the rest of variables. The privacy and confidentiality of participants were secured by the anonymous questionnaire. The hard copies were saved in a special cabinet in the researcher house until the end of the study. The electronic data were pass word protected. Only the board of study in had the ability to provide access to the data Data analysis Data analysis using SPSS package (V 16.0) took place after data collection completion. A double entry technique was used to minimize data entry errors. The independent variables were: work posture, stressful arm positions, work duration, work load, work related psychological factors, individual characteristics of dentist (age, sex, height, and BMI), exercise, education on musculoskeletal symptoms management, and years of actual dental experience. The dependent variables were musculoskeletal symptoms as reported by dentists. The values of exposure variables (standing posture, sitting posture, awkward back posture, and stressful arm positions) were combined into binary variable values where (never, and sometimes) were given the value of (0), while (often, and always) were given the value of (1). The rationale 32

34 among dentists behind this combining is the need to distinguish dentists who experience high level of exposure from dentists working under low exposure levels in relation to the development of the outcome. The continuous values of exposure variables (age, height, BMI, practice years, total working hours, working without break duration, and physical work load) were also combined into binary variable values (0, 1) according to the value of third quartile in each variable as a cut off point. Regarding the remaining exposure variables (psychological work factors, exercise, and knowledge) a score variable (with continuous values) was created for each of them, and also combined into binary variable according to the value of third quartile in each variable as a cut off point. The rationale behind this combining is also distinguishing dentists with high exposure from their colleges with lower levels of exposure. The values of outcome variables were divided into four main categories: No pain category where (never=1, sometimes=0, often=0, and always=0) in this category the outcome of choice is dentists who do not experience any pain. This combining may demonstrate weather the exposure has an influence on preventing the occurrence of the outcome. Mild pain category where (never=0, sometimes=1, often=1, and always=0). Moderate pain category where (never=0, sometimes=0, often=1, and always=1). Severe pain category where (never=0, sometimes=0, often=0, and always=1). The outcome of choice in the last three categories is dentists who experience mild, moderate and severe pain. The association between the exposure and the risk of developing the outcome might be shown in this combining. The rationale behind this combining is the need to investigate the ability of extreme values (never, always) of generating significant associations with risk factors, as those values are less likely to be reported by participants because of the fact the dentists with severe complaints are likely to be retired, in addition there are many different reasons other than dental practice to report musculoskeletal pain. The rationale behind merging (often) with (sometimes) for mild pain, and (always) with (often) for moderate pain; was to reduce possible exaggeration resulting from participants overstatement on their musculoskeletal symptoms. 33

35 among dentists The prevalence of musculoskeletal symptoms in neck, low back, shoulder, and wrist/hand and their consequences within the past year was calculated.univariate logistic regression analysis with of significance level of (P<0.05) was performed to evaluate the influence of standing posture, sitting posture, individual characteristics, physical, psychosocial factors at work, exercise, and knowledge on the incidence of musculoskeletal symptoms in each of the four body organs. Next, a backward stepwise method in multivariate regression was used where all available variables were fitted and then those not significant were discarded sequentially (Campbell, 2006, p. 27). The rationale behind the choice of backward method is to avoid unnecessary exclusion of predictors with significant effects, and thus minimize type II error (Field, 2006, p. 227). 34

36 among dentists Chapter 4 Results 4.1. Basic Characteristics of participants A total of 262 dentists participated in the study. Participants age ranged between (22 74) years with mean age of (37.66) years and standard deviation (9.49) years. Age distribution of participants is illustrated in figure 4.1. Male dentists represented (73.7%) of study population. (55.6%) of dentists were general practitioners, while (44.4%) had higher educational degrees (figure 4.2). Married dentists represented (67.9%). The average of dental practice years for dentists was (12.56) years. Dentists worked for (7.63) hours per day on average. Table 4.1 outlines participants basic characteristics. 50 < 9.2% PHD 3% other degree 10% % < % master degree 32% GB 55% Figure 4.1 Age distribution of participants Figure 4.2 participants distributed by educational degree 35

37 among dentists Table 4.1 Basic characteristics of participating dentists in the study stratified by gender. Males(n=193) females(n=69) Age in years: mean( SD) n= (9.7) 37.6 (8.8) Height(cm): mean( SD) n= (6.8) (4.5) BMI (kg\m 2 ): mean( SD) n= (3.9) 24.5 (3.9) Marital status (%) n= 262 Single Married Other Educational level (%) n= 261 basic higher Duration of practice years: mean( SD) n= (10.1) 12.1 (7.9) Daily work time (%) n= 262 Part time Full time Daily working hours: mean (SD) n= (2.2) 6.3 (2.3) 4.2. Prevalence of musculoskeletal complaints The prevalence of musculoskeletal complaints and their consequences among dentist during the last year is presented in table 4.2. Low back pain was the most prevalent musculoskeletal complaint reported by (35.7%). Followed by shoulder and neck pain experienced by (21%, 20.6%) of dentists respectively. Hand\wrist pain was less prevalent reported by (16%) of dentists. (34%) of dentists suffered chronic musculoskeletal complaints that lasted more than a month during the last year, while (29.1%) reported medical care seeking because of musculoskeletal pain. (16.1%) of dentists had to take sick leave during the last year, and (15%) reported that musculoskeletal pain had affected their daily activities. 36

38 among dentists Table 4.2 prevalence of musculoskeletal complaints and their consequences Neck Low back Shoulder Hand\wrist pain (n=262) pain (n=261) pain (n=262) pain (n=262) Total $ Prevalence% # Chronic complaints% (n=262) Effect on daily activity% (n=262) Work absence% (n=262) Medical seek% (n=262) # Prevalence calculated according to (often, always) values. $ Total value is less than the sum of adjacent row values because of repetition in participants answers Pain severity 50.2% (n=131) of participants ranked their pain over 40 on the visual pain scale (table 4.3). Those who reported >40 on pain scale; were significantly more likely to be female dentists (X 2 =14.08, P<0.0001), experiencing chronic complaints (X 2 =11.29, P<0.001), suffering loss of daily normal activity (X 2 =4.33, P<0.05), being absent from work because of pain(x 2 = 10.11, P<0.005), and seeking medical care (X 2 = 19.11, P<0.0001). 37

39 among dentists Table 4.3 severity rating of pain cross tabulated by sex and musculoskeletal consequences Sex males N=261 Females Chronic pain Yes N=261 No Loss of daily activity Yes N=259 No Work absence Yes N= 260 No Medical seek Yes N= 257 No Pain rating n (%) < 109(56.8) 83(43.2) 21(30.4) 48(69.6) 31(35.2) 57(64.8) 99(57.2) 74(42.8) 13(34.2) 25(65.8) 116(52.5) 105(47.5) 11(26.8) 30(73.2) 118(53.9) 101(46.1) 21(28.4) 53(71.6) 107(58.5) 76(41.5) X 2 (P-value) 14.08(0.000) (0.001) 4.33 (0.037) (0.001) (0.000) 4.4. Presence of risk factors The presence of reported risk factors is shown in table 4.4. (65.3%) of dentists reported assuming sitting posture, while (24.8%) reported assuming standing posture. Awkward back posture during dental practice was reported by (37.8%) of dentists, and (24.8%) of them experienced stressful arm positions while working. (21.2%) of dentists were obese (BMI 30). Dentists spent an average of (12. 6) years in dental practice. They worked on average (7.6) hours per day, and an average of (4.1) hours without a break. (67.6%) of dentists reported practicing exercise once a week or more. 38

40 among dentists Table 4.4 presence of risk\ preventive factors Risk factor N (%) Standing posture $ Sitting posture $ Awkward back posture $ Stressful arm positions $ BMI 30 Sex (males) 65 (24.8) 171 (65.3) 99 (37.8) 65 (24.8) 55 (21.2) 193 (73.7) Risk factor Mean(third quartile) Age! Practice years! Working hours! Working without break! Height! Physical work load! Psychological factors # Exercise # Knowledge & education # 37 (43.5) (17) 7.63 (9) 4.11 (5) 172 (178) 55 (69) 4.74 (6) 6.31 (8) 3.75 (4) $ Presence of risk factor represented by (often, always) values.! Continuous variables combined into binary variables at a cutoff point of third quartile value. # Score values considered Continuous variables and combined at a cutoff point of third quartile value. 39

41 among dentists 4.5. The association between risk factors and musculoskeletal pain The summary of univariate association between risk factors and musculoskeletal complaints for neck, low back, shoulder, and hand\wrist is demonstrated in tables 4.5, 4.6, 4.7, 4.8, respectively Standing and sitting posture There was no evidence of increased risk of developing musculoskeletal pain at any level (mild, moderate, severe) in neck, low back, shoulder, or hand\wrist accompanied with assuming standing or sitting posture in dental practice. However, standing posture was significantly associated with higher likelihood of preventing LBP (OR= 1.88, P<0.05). While a significant association was found between sitting posture and lower probability of preventing LBP (OR=0.56, P<0.05). Sitting posture was also significantly associated with higher probability of preventing hand\wrist pain (OR= 1.86, P<0.05) Awkward back posture and stressful arm positions Increased risk of developing moderate NP was significantly associated with assuming awkward back posture and stressful arm positions during practicing dentistry (OR=3.54, 2.06, P<0.05) respectively. While the risk of developing severe NP was significantly increased in association with awkward back posture (OR=2.94, P<0.05). Assuming stressful arm positions in dental practice was also significantly associated with increased risk of developing moderate and severe shoulder pain (OR= 3.48, 3.24, P<0.05) respectively, and increased risk of developing hand\wrist pain (OR= 2.76, P<0.05) Personal characteristics of dentists Participants age had an ambiguous association with developing musculoskeletal complaints. Whilst the risk of developing mild NP was significantly reduced with age (OR=0.54, P<0.05), the risk of developing moderate and severe shoulder pain was significantly increased with age (OR= 2.12, 6.74, P<0.05) respectively. The same for developing moderate and severe hand\wrist pain where the risk was increasing with age (OR= 2.14, 7.78, P<0.05) respectively. L BP was not significantly related to age. Body mass index of the participants did not show any significance in association with developing musculoskeletal complaints. However, participants height had different affect on developing 40

42 among dentists complaints according to body organ. In case of low back; being taller significantly reduced the probability of preventing the pain (OR=0.48, P<0.05). Yet the risk of developing shoulder and hand\wrist pain was significantly lower in taller dentists (OR= 0.45, 0.36, P<0.05) respectively. Female dentists showed significantly higher risk of developing musculoskeletal complaints compared to male dentists. Being a male dentist significantly reduced the risk of developing severe NP (OR= 0.33, P<0.05), moderate and severe shoulder pain (OR= 0.22, 0.16, P<0.05) respectively, moderate and severe hand\wrist pain (OR= 0.15, 0.1, P<0.05) respectively, and significantly increased the probability of preventing hand\wrist pain (OR= 2.1, P<0.05) Risk factors in work environment A significant association was found between long duration of dental practice and increased risk of developing severe shoulder and hand\wrist pain (OR=6.86, 4.42, P<0.05) respectively. Extended daily working hours was also found significantly associated with developing mild neck and shoulder pain (OR= 1.97, P<0.05) for both. As well as significantly reducing the probability of preventing shoulder pain (OR= 0.47, P<0.05). Working longer hours without taking a break significantly increased the risk of developing moderate shoulder pain (OR= 2.24, P<0.05). Increased physical work load in dental practice was associated with a significant increase in the risk of developing mild and moderate NP (OR= 2.09, 3.23, P<0.05) respectively, as well as the risk of developing mild and moderate shoulder pain (OR= 1.91, 2.12, P<0.05) respectively. It was also associated with reduced probability of preventing neck and shoulder pain (OR= 0.31, 0.45, P<0.05) respectively. Work related psychological factors (high job demands, low job control, feeling tired after work) were significantly associated with an increased risk of developing mild neck, shoulder, hand\wrist pain (OR= 2.11, 1.97, 2.03, P<0.05) respectively. They decreased the likelihood of preventing LBP (OR= 0.49, P<0.05), as well as increasing the risk of developing moderate LBP (OR=2.05, P<0.05) Exercise Practicing exercise proved to be significant in association with higher probability of preventing NP (OR= 4.73, P<0.05), also in association with significantly reducing the risk of developing mild NP (OR= 0.22, P<.05). Although not significant there was a weak indication of increased preventive 41

43 among dentists probability for hand\wrist pain (OR=2.28, P=.08), and decreased risk of developing moderate NP and mild LBP (OR=0.17, P=.09), (OR= 0.43, P=0.06) respectively Knowledge and education Knowledge and education about risk factors of developing musculoskeletal complaints and about preventive measures to avoid these complaints seemed to be not significant in association with developing musculoskeletal pain in this study Multivariate analysis The results of multivariate analysis for risk factors on musculoskeletal complaints in neck, low back, shoulder, and hand\wrist are shown in tables 4.9, 4.10, 4.11, 4.12 respectively Neck pain (NP) Strongest risk factors for developing NP in the model were Physical work load with odds ratio of (0.32) in association with reduction in the probability of preventing the pain, and Psychological work factors with odds ratio of (2.19) in association with developing mild NP. The association between Practicing exercise and increased likelihood of preventing NP became stronger with (OR = 5.12), while decreasing the risk of developing mild NP in association with exercise kept on significant with (OR = 0.23) after adjustment with other risk factors. Risk factors for moderate and severe NP showed no significance in the model Low back pain (LBP) The association between awkward back posture and decreasing the probability of preventing LBP became significant with (OR = 0.33). the association between psychological risk factors at work and the risk of developing moderate LBP became slightly stronger with (OR = 2.17), whereas being a male dentist became significant protective factor against developing the pain (OR =0.39). Increased height of dentists also became significant risk factor for developing moderate LBP (OR =2.37). 42

44 among dentists Shoulder pain Standing posture became significantly associated with increased probability of protection against shoulder pain (OR = 6.98), and with decreasing the risk of developing mild pain (OR = 0.3).While awkward back posture and psychological factors at work became associated with decreased likelihood of protection against the pain (OR = 0.39, 0.38) respectively. The association between psychological factors at work and developing mild shoulder pain became stronger with odds ratio of (2.54). As well the association between stressful arm positions and age and between increased risk of developing moderate shoulder pain became stronger (OR = 7.48, 2.97) respectively. Increased height of dentists had also stronger association with reduced risk of developing the pain (OR = 0.19). Whereas age of dentists had stronger association with increased risk of developing severe shoulder pain with (OR= 19.22) Hand\wrist pain Psychological factors at work and sex of dentists were the only significant risk factors for developing hand\wrist pain after model adjustment with other risk factors. With (OR = 2.49) the association between psychological factors at work and developing mild hand\wrist pain became stronger. Yet the association between being a male dentist and reducing the risk of developing hand\wrist pain became a slightly weaker with (OR = 0.28). 43

45 Table 4.5.Univariate association between neck pain and risk factors Standing posture Sitting posture Awkward back posture Stressful arm positions Age Height BMI Sex Practice years Working hours Working without break Physical work load Psychological factors Exercise Knowledge NO pain N=1, ST= 0, O=0, A=0 * OR % CI P- value *n = never, ST = sometimes, O = often, A = always OR Neck pain Mild pain N=0, ST=1, O=1,A=0 95% CI P- value OR Moderate pain N=0, ST=0, O=1, A=1 95% CI P- value Severe pain N=0, ST=0, O=0, A=0 OR % CI P- value effect of work posture on developing LBP & NP among dentists 44

46 Table 4.6.Univariate association between Low back pain and risk factors Standing posture Sitting posture Awkward back posture Stressful arm positions Age Height BMI Sex Practice years Working hours Working without break Physical work load Psychological factors Exercise Knowledge NO pain N=1, ST= 0, O=0, A=0 * OR % CI P- value *n = never, ST = sometimes, O = often, A = always OR Low back pain Mild pain N=0, ST=1, O=1,A=0 95% CI P- value OR Moderate pain N=0, ST=0, O=1, A=1 95% CI P- value Severe pain N=0, ST=0, O=0, A=0 OR % CI P- value effect of work posture on developing LBP & NP among dentists 45

47 Table 4.7.Univariate association between shoulder pain and risk factors Standing posture Sitting posture Awkward back posture Stressful arm positions Age Height BMI Sex Practice years Working hours Working without break Physical work load Psychological factors Exercise Knowledge NO pain N=1, ST= 0, O=0, A=0 * OR % CI P- value *n = never, ST = sometimes, O = often, A = always OR Shoulder pain Mild pain N=0, ST=1, O=1,A=0 95% CI P- value OR Moderate pain N=0, ST=0, O=1, A=1 95% CI P- value OR Severe pain N=0, ST=0, O=0, A=0 95% CI P- value effect of work posture on developing LBP & NP among dentists 46

48 Table 4.8.Univariate association between shoulder pain and risk factors Standing posture Sitting posture Awkward back posture Stressful arm positions Age Height BMI Sex Practice years Working hours Working without break Physical work load Psychological factors Exercise Knowledge NO pain N=1, ST= 0, O=0, A=0 * OR % CI P- value *n = never, ST = sometimes, O = often, A = always OR Hand\wrist pain Mild pain N=0, ST=1, O=1,A=0 95% CI P- value OR Moderate pain N=0, ST=0, O=1, A=1 95% CI P- value Severe pain N=0, ST=0, O=0, A=0 OR % CI P- value effect of work posture on developing LBP & NP among dentists 47

49 Table 4.9 multivariate analysis of risk factors for NP Neck No pain Mild pain Risk factor OR 95% CI P Risk factor OR 95% CI P Physical load Psychological exercise factors Exercise Sitting posture Work without break Moderate pain Severe pain Risk factor OR 95% CI P Risk factor OR 95% CI P Awkward Back Psychological factors posture Physical load exercise Table 4.10 multivariate analysis of risk factors for LBP Low back No pain Mild pain Risk factor OR 95% CI P Risk factor OR 95% CI P Awkward Back posture Sitting posture Moderate pain exercise Severe pain Risk factor OR 95% CI P Risk factor OR 95% CI P Psychological factors Sex height Awkward Back posture

50 Table 4.11.multivariate analysis of risk factors for shoulder pain. Shoulder No pain Mild pain Risk factor OR 95% CI P Risk factor OR 95% CI P Standing posture Awkward Back posture Psychological factors Age Height BMI Moderate pain Standing posture Psychological factors BMI Severe pain Risk factor OR 95% CI P Risk factor OR 95% CI P Stressful arm Posit Age height Age height work Hours Knowledge Standing posture

51 Table 4.12 multivariate analysis of risk factors for hand\wrist pain Hand\wrist No pain Mild pain Risk factor OR 95% CI P Risk factor OR 95% CI P Work Hours Psychological factors Psychological factors Stressful arm Positions Moderate pain Severe pain Risk factor OR 95% CI P Risk factor OR 95% CI P sex Awkward Back posture Stressful arm Positions Work without break No significant risk factors 50

52 Chapter 5 Discussion This thesis represents the first epidemiological cross-sectional study on prevalence of musculoskeletal complaints among Syrian dentists in Damascus. It investigated the association between work posture in dental practice and other (personal \ at work) risk factors and between developing musculoskeletal complaints. It also examined the effect of exercise and education on protection against musculoskeletal complaints. The choice of the sample from Damascus dental association was based on the fact that all working dentists in Damascus (as well as other governorates) are registered in the dental association by law (dental practice license is not granted unless dentist is registered in dental association). A sample from such a comprehensive study population may accurately represent all dentists in Damascus. Reaching a favorable response rate of study participants at (67.75%) has been relatively difficult and time consuming. The main reasons for none participation in the study were lack of interest and trust in research, lack of motivation, and limited time. Conducting interviews through telephone calls undoubtedly improved response rate and represented a feasible approach to enhance participation in such research. Male dentists were dominant in the study sample representing (73.7%) which might reflect the reality of dental practice in the Syrian context. several female dentists were found permanently or temporarily not working in their clinics and substituted by male dentists The main results Prevalence of musculoskeletal complaints The results of this study indicated relatively high prevalence of low back, neck, shoulder, and hand\wrist pain at (35.7, 20.6, 21, 16%) respectively. The present findings seem to be consistent with other research which found similar prevalence for neck and low back pain (AlWazzan et al , Alexopoulos et al ), for shoulder pain (Abduljabbar , Alexopoulos et al ), and for hand\wrist pain (Abduljabbar, 2008). However, several other studies reported considerably higher prevalence of pain in these body sites (Finsen et al. 1998, Szymanska 2002, Leggat and Smith- 2006, Droeze and Jonsson- 2005). In addition to the reasons 51

53 mentioned earlier in the literature review, these variations in prevalence can be explained in part by researcher s subjectivity when combining variables during data analysis, or the nature of the questions being asked to participants and their ability to reflect what dentists really experience. For instance in this study the choice of (often and always) values to be included in the analysis as positive values for prevalence was made in order to avoid over estimation of the results. The addition of (sometimes) value as positive for prevalence in the analysis would have resulted in huge increase in the prevalence values, and thus reflected falsely exaggerated outcome musculoskeletal consequences In this study, musculoskeletal complaints of dentists were found to be associated with huge burden on their careers. Medical care seeking because of musculoskeletal complaints were reported by (29.1%) of participants which is relatively close to what was found by (Alexopoulos et al., 2004) and (Leggat and Smith, 2006) who reported that (32%, 37.5%) of dentists sought medical care in Greece and Queensland (Australia) respectively. furthermore (15%) of the study participants reported work absenteeism due to musculoskeletal problems which is less compared to (24%) reported by AlWazzan et al. (2001) in Saudi Arabia. And higher compared to (9.1%) reported by Leggat and Smith (2006) in Queensland (Australia). Nationally, the burden of MSDs in population (calculated as percentage of lost DALYs) represented (2.5%) of total burden of all diseases in Syria in 2005 (Lasser, 2007) Association with risk factors Although standing posture in dental practice was found to be associated with increased likelihood of protection against developing LBP and with deceased risk of developing mild shoulder pain (after adjustment with all other risk factors), while sitting posture was associated with decreased likelihood of protection against developing LBP and increased likelihood of protection against developing hand\wrist pain; yet, the current study did not show any significant increase in the risk of developing musculoskeletal pain accompanied with assuming merely standing or sitting posture during dental practice. Therefore dentists may be at risk of developing musculoskeletal pain weather they stand or sit while practicing dentistry. On the other hand the results of this study indicated that extended awkward static postures for back and hands during dental practice were significantly associated with increased risk of developing neck, low back, shoulder, and hand\wrist 52

54 pain. The present findings seem to be consistent with other research which found that prolonged static and unsupported awkward postures in dental practice are major risk factors for developing musculoskeletal pain for dentists (Valachi and Valachi, 2003a - Finsen et al., 1998 Callaghan and McGill, Novak and Mackinnon, 1997). According with earlier observations as previously mentioned in the literature review (Alexopoulos et al., 2004, p. 7 - Finsen et al., 1998, p. 124), this study also revealed unclear association between age and developing musculoskeletal complaints. Older dentists in this study were at higher risk of developing shoulder and hand\wrist pain, but at the same time they had lower risk of developing NP. Nevertheless the results of multivariate analysis indicated that age was significant only as a risk factor for developing shoulder pain. Possible explanations for results variation were dropping out of severe cases form dental profession or developing coping strategies against musculoskeletal complaints by older dentists. However, this inconsistency may be explained by considering that age of dentist may not be firmly correlated to dental practice, therefore, it might not be an accurate estimate for predicting the risk of developing work related musculoskeletal complaints. This is supported by the fact that not all the dentists practice dentistry immediately after graduation, furthermore many dentists experience cessation periods during their careers especially female dentists for reproductive and parental reasons. In contrast to earlier findings (Chowanadisai et al , Leggat and Smith 2006, Finsen et al. 1998, Milerad and Ekenvall ), the current study found that more experienced dentists with longer duration of years in dental practice had significantly higher association with increased risk of developing shoulder and Hand\wrist pain. The findings of the previous studies were mostly explained by the healthy worker effect in which dentists with severe musculoskeletal conditions would have ceased working. A possible explanation for the current results might be that on the contrary many Syrian dentists with severe pain are still practicing dentistry in order to fulfill their financial requirements which otherwise be compromised in the state of inadequate insurance and retirement schemes. Very little was found in the literature about the effect of height on developing musculoskeletal complaints. The current study showed that taller dentists were at higher risk of developing LBP which corroborates with previous findings of Walsh et al. (1991).taller dentists may have to over 53

55 bend their backs in order to acquire closer view of the patient s work field. It is therefore likely that such connections exist between tall dentist and LBP. However, in contrast to the findings of Alexopoulos et al. (2004) it was somewhat surprising that taller dentists were at lower risk of developing shoulder and hand\wrist pain. The reason for this is not clear, but it might be hypothesized that tall dentists have enhanced hand control over their work field, and they can complete the treatment tasks with less repetitive movements of their hands and shoulders. Another unanticipated finding of this study was the association between dentists BMI and developing musculoskeletal complaints, where over weighted dentists did not show any significant difference in regards higher risk of developing musculoskeletal pain. Previous studies indicated a link between overweight and musculoskeletal pain especially LBP (AlWazzan et al.\, Liuke et al., Hamann et al., 2001). However, Leboeuf-Yde (2000) reveled in a systematic review on the link between overweight and low back pain that there is insufficient evidence to consider overweight as a cause of low back pain, and it should be regarded as a weak risk indicator, which might support the results of this study. Consistent with previous research (Leggat and Smith 2006, Finsen et al. 1998, Alexopoulos et al ) the findings from the present study clearly indicate that female dentists were at higher risk for developing musculoskeletal complaints especially low back and hand\wrist pain. Assuming similarity in daily dental tasks for both genders, higher vulnerability to developing musculoskeletal complaints for female dentists might be explained by physiological and hormonal differences as earlier explained in the literature review. Working longer hours in dental settings tended to be associated with increased risk of developing neck and shoulder musculoskeletal complaints. This also accords with earlier observations, which showed significant link between extended work hours and developing musculoskeletal pain (Finsen et al. 1998, Alexopoulos et al , AlWazzan et al ). A simple direct explanation for this link is that working long hours in static postures causes continuous contraction of muscles and obstructs the necessary muscle recovery process, which Predisposes trigger Points and fatigue for the muscles and thus causes pain. Similarly working continuously without short rest breaks was found to be linked with developing shoulder pain. This finding is supported with that found by Marshall et al. (1997) and Valachi and Valachi (2003a) who suggested that frequent breaks 54

56 especially if accompanied with stretching exercises can help with reversing muscles physiological changes which accumulates while working, and with improving blood circulation in those muscles. In this study high perceived physical work load by participants was found to be associated with increased risk of developing neck and shoulder pain. Excessive work load may indicate higher energy cost by the body to produce the essential power for performing extra dental tasks, which might explain the burden on the musculoskeletal system. Alexopoulos et al. (2004) found similar results and demonstrated that physical work load is an important risk factor for developing MSDs particularly for hand\wrist complaints. The effect of psychological risk factors for musculoskeletal pain has been demonstrated in the literature. Linton (2000) found in a systematic literature review of (37) prospective studies that psychological factors had an important role in developing acute and chronic neck and back pain. Interestingly the results of this study indicated a significant association between higher exposure to psychological risk factors in dental settings and developing musculoskeletal complaints in all studied body parts, even after confounding with other risk factors in multivariate analysis, psychological risk factors were still significant in all body parts, indicating an important link. However psychological factors were significant for mild and moderate but not for severe pain, which might be explained on the basis of psychosomatic symptoms that originate because of fatigue and emotional stress and contribute with other physical risk factors in developing musculoskeletal complaints. Dental practice in Syria unlike other developed (or even some neighboring) countries is not considered of the highest sources of income because dental treatment costs are considerably lower compared to these countries, and with recently growing individual financial demands under the Syrian process of transmission into social market economy in addition to the sophisticated social burden of dentists as highly classified in social status ; it is possibly the accumulation of these reasons that might represent the underlying basis of the strong association between work related psychological factors in dental practice and developing musculoskeletal complaints for dentists. The importance of exercise has been demonstrated in this study as preventive against developing musculoskeletal complaints especially for NP. This result corroborates with a recent systematic review which revealed that exercise - mainly Trunk strengthening - is useful for 55

57 people suffering chronic LPB, whereas it helps them to regain their daily work activities (Slade and Keating, 2006). The result is also consistent with the findings of Hayden et al. who suggested that Dentists who often assume static posture at work may benefit exercise to maintain healthy neck and back (Hayden et al., 2005, p. 776). Contrary to expectations, this study did not find a significant association between dentists knowledge on symptoms and risk factors of musculoskeletal disorders, or education among dentists on protection against musculoskeletal symptoms and between the risk of developing musculoskeletal pain. It seems possible that this result is due to approximate knowledge levels among study participants where about (75%) of them had a knowledge score 4 (out of 10) and (61.7%) of them had knowledge score = 4. The lost knowledge score points among participants were mainly attributed to the absence of education and training courses and programs regarding musculoskeletal complaints in dental practice whether before or after graduation. The lack of variation in knowledge levels of dentists might have resulted in failure of deriving significant associations Interventions to reduce musculoskeletal complaints in dentistry The use of theory to direct the practice of health interventions has been proved to be effective (Jackson, 1997, p. 143). Integrating the framework of health behavior change theories in the process of promoting consequences and prevention on musculoskeletal disorders among dentists may have positive impact on reducing musculoskeletal complaints in dentistry. Theory of Reasoned Action suggests that a person's behavior is determined by his/her intention to perform the behavior and that this intention is, in turn, a function of his/her attitude toward the behavior and his/her subjective norm. This intention is determined by three things: their attitude toward the specific behavior, their subjective norms and their perceived behavioral control. (Elder et al., 1999, p. 228). Practice interventions (such as stress management, exercise and ergonomic education) must focus on promoting knowledge, improving self-skills and strengthening social support in order to reduce the complaints (Ryan, 2009, p. 161). The promotion of a successful campaign to change unhealthy behaviors leading to development of MSDs must be based on solid theoretical frame work including understanding the dentists attitudes and beliefs 56

58 about MSDs, clarifying health benefits of prevention that enable dentists to take positive attitudes towards prevention from MSDs, investigating dentists perceived barriers against behavior change, reinforcement of dentists personal control over behavior and increasing self confidence in ability of behavior change (OHPRS, 2010). Integrating these elements in developing a health promotion program to reduce the prevalence of MSDs will definitely maximize the benefits. Based on the study results, the most appropriate interventions to prevent development of work-related musculoskeletal complaints in dental practice is to provide dentists with comprehensive knowledge about risk factors, mechanisms, symptoms, and management of these complaints including ergonomic education, exercise, and lifestyle Education Education is a lifelong concept. Dentists who want to continue their profession along with maintaining good health; are obliged to learn about musculoskeletal health and dental ergonomics. Theoretically education on musculoskeletal health must be integrated in dental school programs and continue with the dentist through his career (Valachi and Valachi, 2003b, p. 1611). Unfortunately dental ergonomics education -before and after graduation- is still very limited in prevalence and efficiency (Murphy 1998, cited in Valachi and Valachi, 2003b). The reason behind this may be the lack of research, lack of trained teachers and prober programs and tools (Valachi and Valachi, 2003b, p. 1611). A preventive education strategy that targets dentists is necessary to avoid musculoskeletal consequences. This strategy should include work posture techniques, methods for selecting and use of ergonomic equipment and finally emphasis on the importance of exercise and repeated breaks during work (ibid.) Exercise It has been established in the literature that physical exercise increases the resistance against back injuries (Mayfield clinic, 2009a, p. 1). The most effective exercises are based on programs that target individuals under supervision and follow-up by experts (Hayden et al., 2005, p. 776). Different types of exercises were suggested to prevent musculoskeletal complaints 57

59 (Mayfield clinic, 2009b, p. 3). The most popular types are: Strengthening exercises, stretching exercises, and aerobic exercises. Appendix 8 illustrates some of Chairside stretching exercises 5.3. study limitations and the need for further research Several limitations to this study need to be acknowledged. The main weakness of this study was that the risk factors and musculoskeletal complaints reported by participants might actually be different from their real conditions. However, the homogeneous medical back ground of the participants may possibly reduce such discrepancy. Recall and non-responding bias had to be taken into consideration(by limiting recall period by one year and making phone call interviews for non-respondents) as they might influence the integrity of the associations. This study was unable to prove the causal relation between risk factors in dental practice and developing musculoskeletal complaints because time was not taken into account in the study design. An important source of bias might have emerged from the healthy worker effect, where none working dentists with the most severe symptoms might have been excluded from participation in the study. Although calculated according to EPI-INFO and the population of Syrian dentists, the size of study sample indicated a sort of low statistical power represented by the wide range of the confidence interval in some associations which means that these associations need to be interpreted with caution. Future research should concentrate on establishing the association between the assumed risk factors and developing MSDs through study designs that takes time into consideration such as cohort or case control studies. More information on the differences between male and female dentists in relation to musculoskeletal pain response would be important to establish a greater degree of accuracy on this topic. Qualitative studies are needed to better understand the role and mechanism of psychological risk factors in developing MSDs. Larger and more geographically spreading cross-sectional studies could provide more definitive evidence on prevalence and association with risk factors for MSDs in dental practice. Evaluation of social and economic burden of MSDs in dental practice would support epidemiological research to elucidate different aspects of this occupational health issue. 58

60 Chapter 6 Conclusions and recommendations 6.1. Conclusions Based on the preceding results and discussion, and consistent with dissertation objectives, the following conclusions can be derived: The study has reported the prevalence and burden of musculoskeletal complaints, as well as the presence of hypothesized risk factors among Syrian dentists at (95%) confidence level. The study has shown that generally significant associations exist between risk factors related to dentists personal and physical characteristics, prolonged static work postures, and other work related factors, and between developing musculoskeletal complaints. Multiple regression analysis revealed that work related psychological factors were constantly associated with developing mild and moderate musculoskeletal complaints. The most appropriate interventions to reduce the prevalence of musculoskeletal complaints are theoretical based interventions including education, ergonomic training programs, and promoting exercise practice. The present study confirms previous findings of research and contributes additional evidence that musculoskeletal disorders represent a serious health and occupational concern in modern dental practice. Nationally, this research will serve as a base for more future studies to establish the relation between studied risk factors and developing musculoskeletal complaints. Further research is required to better understand the role and mechanism of psychological risk factors in developing MSDs. 59

61 6.2. Recommendations Preventing musculoskeletal complaints among Syrian dentists proved to be a critical health and financial issue considering the burden they represent. Prevention against musculoskeletal disorders may represent the key element for Syrian dentists to safely practice dentistry and to avoid disability and early retirement, as well as for government to preserve important human and financial assets in a time of scarcity of resources. In the process of comprehensive prevention plan the following aspects are crucially recommended: Safety legislation MOH in collaboration with other related ministries are required to enhance occupational safety regulations to cover all occupations including dentistry. Concerning dentistry, the regulations are expected to set rules for prevention against occupational risks including musculoskeletal risks, and provide adequate information for safety in dental settings Preventive education To avoid the development of MSDs, dentists and dental students must have the knowledge about musculoskeletal health and mechanisms that contribute to MSDs. Dental schools should be responsible for providing ergonomic training programs in their curricula including correct working posture, use of ergonomic equipment, and management of MSDs. While the role of dental associations in collaboration with MOH is to increase ergonomic awareness through promoting training courses and seminars and periodically distributing publications, on musculoskeletal health to the members of dental associations Preventive guidelines Similarly to infection control guidelines in dental clinics, it is important that clear guidelines for musculoskeletal health of dentists are developed and disseminated by MOH and dental associations. The guidelines may include postural strategies, selection of dental equipment, prober exercise techniques, and management of MSDs. Appendix 9 includes ergonomic guidelines in dental practice. 60

62 Promoting physical activity In the process of reinforcing positive attitudes, clarifying the benefits of physical activity in general and prophylactic stretching exercises as daily routine practice would be crucial in preventing the development of MSDs. Promotion of Chairside stretching exercises during micro work breaks is suggested to be included as part of a plan for behavior change framework among dentists. Some Chairside exercises are illustrated in Appendix Management of MSDs To maintain a good musculoskeletal health during his\her career, it is the role of every dentist to implement effective interventions to prevent, control, and manage MSDs. These interventions include selecting ergonomic dental equipment, practicing regular stretching and strengthening exercises, and consulting a certified physical therapist in case of developing chronic musculoskeletal symptoms Surveillance and reporting The development of reporting and surveillance system for musculoskeletal complaints in dental practice (along with other occupations) is essential in strengthening the quality statistical data, and in creating long term prevention and intervention programs. A feasible implementation of this system would be through establishing specialized clinics following health directories to identify, report, and follow up musculoskeletal complaints in a simple, unified method across Syria Research The failure of implementing successful musculoskeletal prevention programs for dentists is in part due to lack of research foundation. Research centers such as can play an extremely important role in providing evidence for decision making and priority setting, especially through conducting longitudinal population based epidemiological studies. They may also take part in promoting the culture of research among all concerned stakeholders to participate in developing such prevention programs. 61

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71 Chapter 8 Appendices Appendix1 Abbreviations Used in this Document BMI EMG LBP MOH MSDs NP WHO YALYs Body Mass Index Center for Strategic Health Studies electromyography Low Back Pain Ministry of health Musculoskeletal disorders Neck Pain World health organization Disability adjusted life years 70

72 Appendix 2 Budget summery Proposal title: The effect of work posture on developing low back pain, neck pain A cross sectional survey in Damascus, Syria Date submitted: 1/27/2011 Master programme: Public health Researcher Osama Samman Total budget 960 (1 = 62.5 sp) Budget line Amount percentage needed in SP Field work and personnel services % Field work transport and communication expenses % Printings and office materials % publication expenses % Any other expenses % TOTAL % The main resource of funding will be the salary of the researcher paid through five months period. 71

73 Appendix 3 Timetable for the Research Project Activities responsibility Time resources Submission of outline proposal for dissertation research project Obtain approval of outline proposal by Ethics Committee Literature review Questionnaire translation &Pilot study Data collection Data entry Data analysis Writing and editing first draft of dissertation Final dissertation submission Researcher Researcher Researcher Researcher Researcher & 2 assistants Researcher Researcher Researcher Researcher 1 to 19 August 2010 By 2 September August 2010 to 30 September to 26 September 1 October to 15 November 5 October to 20 November 21 November to 16December 15 December to 20 January to27 January 2011 Literature, PC, Internet access, printer. time Time, PC, Internet access, Literature Translator, Transport, questionnaire copies, time PC, software(spss), time PC, software(spss), time PC, software(word), time PC, software(word), time Persondays required 1*19 = 19 days 1*42 = 42 days (2* 45) +(1* 25) = 115days 1* 25 = 25 days 1* 25 = 25 days 1*35 = 35 days 1*8 = 8 days 72

74 Appendix 4 Participant Information Sheet Dear respondent: [Greetings] My name is Osama Samman, I am a dentist, and I work with the Syrian Ministry of Health. We are conducting a study about work related complaints in dental practice. The results of this study will be assessed with the specialized management in the Ministry of Health and used constructively to improve your safety in dental practice. To do this survey, we are asking a series of questions about general information, general health, Work environment, psychosocial aspects, symptoms, physical activities, and knowledge and education. Your clinic has been chosen to take part in this survey. There are 38 questions will take approximately 10 minutes to complete. Thank you for your cooperation. Contact address: management@cshs.moh.gov.sy Cell:

75 Appendix 5 Participant Information Sheet Arabic translation الجمهور ة العرب ة السور ة وزارة الصحة مركز الدراسات االسترات ج ة الصح ة أثر وضعية العمل في تطور آالم أسفل الظهر والرقبة عند أطباء األسنان عز زي المشارك ف هذا البحث تح ة ط بة اسم أسامة محمد السمان,وأنا طب ب أسنان أعمل مع وزارة الصحة, نحن نقوم حال ا بدراسة حول الشكا ات المرض ة المتعلقة بالعمل ف مهنة طب األسنان. سوف تم تق م نتائج هذه الدراسة بالتعاون مع الدوائر المختصة ضمن وزارة الصحة واالستفادة منها بشكل فعال لتحس ن سالمتكم أثناء ممارستكم المهن ة. خالل هذا االستب ان, تم وضع سلسلة من األسئلة تتعلق بمعلومات عامة عن المشارك, صحته العامة, طب عة عمله, العوامل النفس ة المتعلقة بالعمل, وجود أعراض مرض ة, ممارسة األنشطة البدن ة, مفهوم المشارك حول األمراض المتعلقة بالمهنة و ك ف ة تجنبها. ولقد تم اخت اركم للمشاركة ف هذا االستب ان علما أن المشاركة اخت ار ة ولن تم استخدام أ ة معلومات شخص ة ضمن هذا البحث, هناك 83 سؤال ضمن هذا االستب ان و اإلجابة عل ها لن تستغرق أكثر من عشر دقائق. و شكرا لتعاونكم الستفساراتكم رجى االتصال على الرقم أو المراسلة على البر د االلكترون management@cshs.moh.gov.sy 74

76 Appendix 6 Questionnaire for Information about developing pain in different body parts among dentists related to dental practice. General information 1. Today's date: 2. Age in years: 3. Sex: Female Male 4. height in M: 5. weight in Kg: 6. educational degree: GP Master degree PHD Other, Specify 7. Are you currently (check only one): married Single widowed divorced 8. How many years have you been working as a dentist without cessation? 75

77 General health 9. In general, would you say your health is: (Circle one) Excellent... 1 Very good... 2 Good... 3 Fair... 4 Poor Please indicate if you have any chronic disease No yes Specify if yes: Work environment 11. Do work with the help of an assistant? never sometimes often always 12. What position do you take while working? Standing: never sometimes often always Sitting: never sometimes often always 76

78 13. While working; do you notice that you assume awkward working postures in which the back is bent or twisted? never sometimes often always 14. While working; do you notice that you apply stressful arm positions (working with hands in excessive tightening and elevated arms)? never sometimes often always 15. Using the following scale please rate the OVERALL physical effort level demanded by your job. Please mark the most appropriate position between the two ends Very, very light Very, very hard 16. When is your working time during the day? Morning evening both 17. How many hours do you work without a break? 18. How many brakes do you have during a working day? 19. What are the total hours of your working time per day? 77

79 Psychosocial aspects 20. Please circle the relevant number next to the question How often: Rarely Sometimes Often always -Does your job require you to work very fast? -Does your job require you to work Very hard? -Does your job leave you with little time to get things done? -how much influence do you have over work & work-related factors? 78

80 Symptoms 21. have you at any time during the last 12 months had trouble(such as ache, pain, discomfort, numbness) in Neck never sometimes often always Lower back never sometimes often always Shoulder never sometimes often always Hand/wrist never sometimes often always Other body parts never sometimes often always Specify (if yes): 22. Have you during the last 12 months had trouble in one of the mentioned body parts that lasted at least for one month? No yes Specify (if yes): 23. Have you at any time during the last 12 months been prevented from carrying out normal activities because of the trouble in one of the mentioned body parts? No yes Specify (if yes): 79

81 24. Have you at any time during the last 12 months been absent from work because pain or discomfort in one of the mentioned body parts? No yes Specify (if yes): 25. Have you at any time during the last 12 months sought medical treatment because of pain or discomfort in the mentioned body parts? No yes Specify (if yes): 26. at the end of a regular workday do you feel that: -you are fatigued after work never sometimes often always -you lack for concentration never sometimes often always -you have the ability to recover from work never sometimes often always 27. describe the degree of your pain(if you have any complaint) by butting a mark between the two ends on the following scale: No pain extreme pain 80

82 Physical Activities 28. Do you practice exercise? never sometimes often always If your answer to question 14 was never go to question How often do you exercise per week? One time two three more 30. For how long do exercise each time? 31. What type of exercise do you practice? Walking running swimming other specify: Knowledge & education 32. In your opinion do think that work posture (standing or sitting) is related to body complaints especially neck and low back pain? Yes no 33. In your opinion do you think that long working hours may be a factor to develop body complaints especially neck and low back pain? Yes no 81

83 34. In your opinion do you think that exercise may help to prevent body complaints especially neck and low back pain? Yes no 35. Have you had any educating courses about healthy habits related to dental work Before graduation Yes no (University curriculum) After graduation Yes no 36. Have you had any educating courses about the management of body complaints especially neck and low back pain? Before graduation Yes no (University curriculum) After graduation Yes no 37. Have you had any educating courses explaining the effect of exercise in preventing body complaints especially neck and low back pain? Before graduation Yes no (University curriculum) After graduation Yes no 38. In your opinion do you think that education on healthy work habits and benefits of regular exercise may help to prevent body complaints especially neck and low back pain? Yes no I don t know 82 Thank you for your help!

84 Appendix7 Questionnaire for Information about developing pain in different body parts among dentists related to dental practice. Arabic translation استبيان حول تطور األلم و الشكوى المرضية في مختلف أعضاء الجسم و المتعلقة بممارسة مهنة طب األسنان معلومات عامة تار خ ال وم العمر )بالسنوات(.1.2 الجنس ذكر أنثى.3.4 الطول.5 الوزن الشهادة طبيب أسىان عام ماج ست ر دكتوراه.6 شهادات أخرى رجى التحد د: : أوج حال ا هل.7 أعزب متزوج أرمل مطلق 8. كم عدد سنوات عملك كطب ب أسنان )بدون انقطاع( 83

85 الحالة الصحية 9. بشكل عام هل تعتقد بأن صحتك ( الرجاء تحد د خ ار مما ل ( : ج دة ممتازة ج دة جدا ال بأس س ئة 10. هل تعان من أ ة أمراض مزمنة ال نعم إذا كان جوابك نعم, فالرجاء تحد د نوع المرض_ العمل بيئة 11. هل حسخعيه أثىاء عملك بمساع دة سىيت غالبا ال مطلقا أح انا دائما 12. ما الىضعيت الخي حخخذها أثىاء قيامك بالمعالجاث السىيت غالبا واقفا ال مطلقا أح انا دائما غالبا جالسا ال مطلقا أح انا دائما 13. أثىاء عملك هل حالحظ أوك حخخذ وضعيت عمل غير مالئمت بحيث يكىن ظهرك مىحىيا أو ملخىيا غالبا ال مطلقا أح انا دائما 14. أثناء عملك هل تالحظ أنك تطبق قوى مجهدة على ذراع ك و د ك ( كرفع الذراع ن عال ا والشد الزائد بال د ن ) ال مطلقا أح انا دائما غالبا 84

86 15. باستخدام المق اس التال, حدد مقدار الجهد البدن المطلوب إلنجاز عملك ف الع ادة السن ة )الرجاء وضع إشارة ف المكان المناسب ب ن طرف المق اس خف ف جدا شد د جدا 16. ما هو وقت عملك أثناء ال وم صباحا مساء كالهما 17. ما هو عدد الساعات الت تعملها دون أخذ استراحة 18. ما هو عدد االستراحات الت تأخذها خالل دوام عملك ال وم 19. ما هو العدد اإلجمال لساعات عملك وم ا 85

87 العوامل النفسية المؤثرة على العمل 20. الرجاء وضع إ شارة حول الرقم المناسب المقابل لكل سؤال مما ل : نادرا أح انا غالبا دائما هل تتطلب منك طب عة عملك 1 أن تعمل بسرعة كب رة هل تتطلب منك طب عة عملك 1 مجهودا شاقا هل تترك لك طب عة عملك 1 وقتا محدودا إلنجاز األش اء ما هو مدى التأث ر الذي تملكه 1 على العوامل المرتبطة بعملك ال وم األعراض المرضية 21. هل واجهت أ ة مشاكل صح ة خالل السنة الماض ة )مثال : عدم راحة - ألم خدر( الرقبة ال مطلقا أح انا غالبا دائما غالبا أسفل الظهر ال مطلقا أح انا دائما غالبا الكتف ال مطلقا أح انا دائما غالبا ال د/ المعصم ال مطلقا أح انا دائما غالبا أعضاء أخرى ال مطلقا أح انا دائما من الجسم الرجاء التحد د 86

88 22. هل واجهت مشكلة صح ة استمرت لمدة شهر أو أكثر ف أحد أعضاء الجسم المذكورة و ذلك خالل السنة الماض ة ال نعم إذا كان جوابك نعم فالرجاء التحد د 23. خالل السنة الماض ة هل امتنعت عن ممارسة أي من نشاطاتك االعت اد ة ال وم ة بسبب مشكلة صح ة ف أي عضو من أعضاء جسمك المذكورة ال نعم إذا كان جوابك نعم فالرجاء التحد د 24. خالل السنة الماض ة هل اضطررت للتغ ب عن العمل بسبب مشكلة صح ة ف أي عضو من أعضاء جسمك المذكورة ال نعم إذا كان جوابك نعم, فالرجاء التحد د 25. خالل السنة الماض ة هل اضطررت لطلب أي معالجة طب ة بسبب مشكلة صح ة ف أي عضو من أعضاء جسمك المذكورة ال نعم إذا كان جوابك نعم, فالرجاء التحد د 26. عند نها ة وم عملك االعت ادي هل تشعر بأنك متعب بسبب العمل ال مطلقا أح انا دائما غالبا تشكو من قلة الترك ز ال مطلقا أح انا دائما غالبا تملك القدرة على التعاف ال مطلقا أح انا دائما غالبا من أعباء العمل 87

89 ال) effect of work posture on developing LBP & NP 27. صف درجة ألمك إذا كنت تعان من آالم بسبب عملك وذلك بوضع إشارة ف المكان المناسب ب ن طرف المق اس التال ال وجد ألم ألم شد د جدا النشاط البدني 28. هل تمارس الر اضة غالبا ال مطلقا أح انا دائما ) فانتقل مباشرة إلى السؤال 28 إذا كان جوابك للسؤال ما هو عدد المرات الت تمارس ف ها الر اضة أسبوع ا مرة واحدة مرت ن ثالث مرات أكثر 30. ما الوقت الذي تستغرقه ف كل مرة تمارس ف ها الر اضة 31. ما هو نوع الر اضة الت تمارسها السباحة الركض المش غ ر ذلك, الر جاء التحد د 88

90 المفهوم العام حول الموضوع 32. حسب رأ ك هل تظن أن وضع ة العمل ف الع ادة السن ة مرتبطة بالمشاكل الصح ة ألعضاء الجسم المذكورة سابقا وخاصة أسفل الظهر و الرقبة ال نعم نعم حسب رأ ك هل تظن أن العمل لساعات طو لة ف الع ادة السن ة مكن أن كون عامال سهم ف تطور المشاكل الصح ة ألعضاء الجسم المذكورة سابقا وخاصة أسفل الظهر و الرقبة ال حسب رأ ك هل تظن أن التمار ن الر اض ة مكن أن تسهم ف منع تطور المشاكل الصح ة ألعضاء الجسم المذكورة سابقا وخاصة أسفل الظهر و الرقبة ال نعم هل تلق ت أ ة دورات تدر ب ة حول العادات الصح ة للعمل ف الع ادة السن ة قبل التخرج )ضمن منهاج الجامعة( نعم ال بعد التخرج نعم ال 36. هل تلق ت أ ة دورات تدر ب ة حول تدب ر المشاكل الصح ة ألعضاء الجسم المذكورة سابقا وخاصة أسفل الظهر و الرقبة نعم نعم قبل التخرج )ضمن منهاج الجامعة( بعد التخرج ال ال 37. هل تلق ت أ ة دورات تدر ب ة حول أثر التمار ن الر اض ة ف منع تطور المشاكل الصح ة ألعضاء الجسم المذكورة سابقا وخاصة أسفل الظهر و الرقبة نعم نعم قبل التخرج )ضمن منهاج الجامعة( بعد التخرج ال ال 38. حسب رأ ك هل تظن أن تعلم العادات الصح ة للعمل ف الع ادة السن ة و التمار ن الر اض ة المناسبة مكن أن حد من تطور المشاكل الصح ة ألعضاء الجسم المذكورة سابقا وخاصة أسفل الظهر و الرقبة نعم ال أعلم ال و شكرا لتعاونكم! 89

91 Appendix 8 Examples for Chairside stretching exercises Adopted from (Valachi, 2008b) 90

92 91

93 92

94 Safe Postural Working Range Head posture: 0 20 degrees. Appendix 9 Ergonomic guidelines in dental practice Adopted from (Valachi, 2008b) Forward arm reach: 0-25 degrees ( 15 degrees requires armrests). Forearms parallel to floor, or angled upward 10 degrees. Hip angle degrees. Positioning Strategies Avoid static postures. Alternate between standing and sitting. Reposition the feet. Position patients at the proper height. Avoid twisting. Operator Stool Adjustment Adjust backrest height so the convex portion aligns with low back curve. Move backrest away from the back. Sit all the way back on the seat (Place 3 finger widths behind the knee. If the closest finger touches the seat, the seat pan is too deep for you). Find neutral posture. Tilt seat slightly forward 5-10 degrees. 93

95 Adjust height till thighs slope slightly downward. Adjust backrest forward to closely nestle in low back curve. Operator position Move to the appropriate clock position to establish a line of sight perpendicular to the tooth surface. This may be direct or indirect. Position delivery system within easy reach. Identify finger fulcrums to enable relaxation of hand/arm. Adjust light to prevent shadowing (within 15 degrees of operator s line of sight). Guidelines for exercise Consult a physician before beginning any exercise program. Do not perform strengthening exercises for painful or fatigued muscles. Begin exercise gradually, starting with the minimum number of repetitions. Stop exercise immediately if numbness, tingling, dizziness or shortness of breath occurs. Perform strengthening exercises three to four times per week and stretching exercises daily. Always exercise in a pain-free range. 94

96 How to Stretch Safely Move into and out of a stretch slowly. Breathe in and exhale slowly as you increase the stretch to a point of mild tension or discomfort. Hold stretch for 2-4 breathing cycles. Try stretch toward both sides to determine tightest side. Stretch toward the tightest side during the workday. Perform stretches in both directions at home and on weekends. Do not stretch in a painful range. Discontinue stretching if pain increases following stretching. 95

97 Appendix 10 Some photos of dentists in working postures Adopted from (Valachi, 2008b) Awkward working postures Photo1: example of poor posture that causes flattened lumbar lordosis. Photo2: repeated awkward posture towards treatment direction 96

98 Correct working postures Photo3: good posture maintains low back curve and reduces pressure on disks and muscles. Photo4: another example of optimal working posture where low back, shoulder, and hands are well supported. 97

99 Ergonomic dental equipment Photo5: contoured headrest enables good positioning of patient s head for treatment of upper arch. Photo6: armrest helps reducing shoulder and neck strain. Photo7: ergonomic dental stool supporting low back curve, and operating telescopes (loupes) to reduce neck flexion. 98