Dental caries prevalence in children attending special needs schools in Johannesburg, Gauteng Province, South Africa

Transcription

1 308 > Dental caries prevalence in children attending special needs schools in Johannesburg, Gauteng Province, South Africa SADJ August 2012, Vol 67 no 7 p308 - p313 CB Nqcobo 1, V Yengopal 2, MJ Rudolph 3, M Thekiso 4, Z Joosab 5 Abstract Introduction: Anecdotal evidence from clinical data in Johannesburg suggests that there is a high burden of dental caries among children with special health care needs (CSHCN) in Johannesburg. Objectives: To determine the prevalence of dental caries and Unmet Treatment Needs in children with cerebral palsy, hearing, learning and mental disabilities attending special needs schools in Johannesburg and to compare these with data from the National Children s Oral Health Survey (NCOHS) Methods: This cross-sectional analytical study comprised of 882 children attending five special needs schools in Johannesburg. Stratified randomised sampling of the participating schools was done and the schools were stratified by disability. Caries status was recorded via the dmft/ DMFT index using WHO criteria and guidelines. 1. CB Nqcobo: BSc, BDS, Faculty of Health Sciences, Dept. of Community Dentistry, University of the Witwatersrand, South Africa. 2. V Yengopal: BChD, BSc Hons, MChD, Faculty of Health Sciences, Dept. of Community Dentistry, University of the Witwatersrand, South Africa. 3. MJ Rudolph: BDS, MPH, Faculty of Health Sciences, Dept. of Community Dentistry, University of the Witwatersrand, South Africa. 4. M Thekiso: BChD; MDent, Faculty of Health Sciences, Dept. of Community Dentistry, University of the Witwatersrand, South Africa. 5. Z Joosab: BDT, Faculty of Health Sciences, Dept. of Community Dentistry, University of the Witwatersrand, South Africa. Corresponding author CB Nqcobo: Registrar/ Associate Lecturer, Wits Medical School, 10th floor, Room 10Q19. Tel: / cathrine.nqcobo@wits.ac.za Acronyms COHOP: Community Oral Health Outreach Programme CSHCN: Children with Special Health Care Needs NCOHS: National Children s Oral Health Survey SHCNS: Special Health Care Needs Schools SiC: Significant Caries Index UTN: Unmet Treatment Needs WHO: World Health Organisation Results: The mean age of the participants was 10.5 years; with a caries prevalence of 27.55% and 33.56% in the primary and permanent dentition respectively. The highest unmet treatment need of 100% was found in the permanent dentition of the hearing impaired group followed by 90.77% in the primary dentition of the cerebral palsy group. In general no significant difference was found when the dmft/dmft for CSHCN and NCOHS were compared except in the hearing impaired age groups four to five and six (both primary dentition) where significantly higher dmft scores (3.58 vs. 2.4; 3.85 vs. 2.9; p<0.05) were found. Conclusion: Children with special health care needs had lower caries prevalence compared with the general population and higher unmet treatment needs regardless of the type of disability. INTRODUCTION Children with special health care needs (CSHCN) are defined as those who have or are at increased risk for a chronic physical, developmental, behavioural, or emotional condition and who also require health and related services of a type or amount beyond that required by children generally. 1 Gauteng Province has 109 special health care needs schools (SHCNS) registered with the Department of Education, of which 42 are located in Johannesburg. These schools are found in the north, south, east, and west of Johannesburg and are categorised by the Department as follows: ordinary, hospital, deaf, special, cerebral palsied, school of focus learning, industrial, child welfare, learning disability, mild mental disability and severe mental disability. This study focused on the following four disabilities: cerebral palsy, hearing impaired, learning disability and mental disabil-

2 / SADJ Vol 67 No. 7 < 309 ity. These disabilities were included because they were the only groups that were accessible to the team. Cerebral palsy is a condition where there is gross delay in the development of motor functions. Children with cerebral palsy have great difficulty in initiating and controlling their muscles and their body movements. Many of these children are perfectly well in all other aspects, such as in their speech, learning ability and socialisation. This differentiates cerebral palsy from mental retardation, which does not have an impact on motor functions. In addition, the legs and arms of patients with cerebral palsy may appear very stiff or limp. 2 Hearing loss, according to the World Health Organisation, refers to the complete loss of hearing ability in one or both ears. Hearing impairment refers to both complete and partial loss of the ability to hear. 3 Mental disability, according to the WHO, is defined as a condition in which there is a delay or deficiency in all aspects of development, 4 i.e. there is a large-scale and noticeable deficiency in the development of motor, cognitive, social, and language functions. Other studies define mental disability as a physical, mental or emotional condition in which an individual has difficulties in doing any of the activities that involve learning, remembering and/or concentrating. 5 The above definitions are often used interchangeably and refer to the same type of patient. For the purpose of the study, Erickson and Lee s definition 5 of mental disability was used. The WHO defines learning disability as a state of arrested or incomplete development of the mind. A person with a learning disability is said to have significant impairment of intellectual functioning and significant impairment of adaptive or social function. 6 People with disabilities such as mental and/or physical disabilities have been reported to have poorer oral health than the general population. 7 Poor oral health can have a significant effect on an individual s quality of life 8 and has a negative impact on nutrition, digestion and the ability to chew and enjoy food. 9 The consequences of unmet oral health needs include infection of oral tissues, negative behaviour and aggravation of associated medical conditions. 10 For the oral health needs of the CSHCN to be met, proper assessment of the extent of the needs should be done so that the data can be used to inform the planning of services. However, little or no data is available on the oral health status of these children in South Africa. This is in stark contrast to the two national oral health surveys ( and ) that provide detailed information on the oral health status of children in South Africa. Hence, this study sought to determine the dental caries prevalence among children attending special needs schools in Johannesburg. The objectives of the study were to determine the dental caries prevalence and unmet treatment needs of children with cerebral palsy, hearing impaired and learning and mental disabilities attending special needs schools in Johannesburg. Additionally, this study sought to compare these results with those reported in the National Children s Oral Health Survey (NCOHS). METHODOLOGY This was designed as a cross-sectional descriptive study with a study population of children aged between three to 18 years of age attending special needs schools in Johannesburg. A list of all the special needs schools in Johannesburg was obtained from the Gauteng Department of Education. From the list, schools were stratified according to the type of disability they serve. Within each stratum, schools were randomly selected and all the children attending the facility were invited to participate in the study. In total five schools were selected. The statistical sample size calculator for descriptive studies on Epi info version was used to determine the sample size which was calculated to be 885 at a confidence level of 95% and assuming a caries prevalence of 65%. This prevalence rate estimate was derived from the Liu et al. 11 study. Study instruments The data collection form is an adaptation of the forms used by the Community Oral Health Outreach Programme (CO- HOP) in the Department of Community Dentistry at the University of the Witwatersrand Johannesburg. The form consisted of two parts: a section that was used to collect demographic data, such as age, gender and disability, and a clinical section, which recorded the presence of decayed, missing and filled teeth (dmft/dmft) and treatment needs. The clinical examination was conducted by three calibrated examiners and the intra- and inter-examiner reliability agreement was assessed using the Cohen Kappa statistic, 12 with an overall score of 0.80 for diagnosis of dental caries. Dental caries examination The selected schools were visited after obtaining permission to conduct the study from the Department of Education. Information letters and consent forms were given to the head teacher with the request that copies be given to the children to take home to parents. Only those children whose parents had provided signed informed consent were included in this study. Dental examinations were carried out from September 2011 through October The participants were examined on site in the school classroom under natural light. The subjects were in a seated position in accordance with the WHO guidelines 13 and were examined using a disposable mouth mirror. Dental caries was scored per tooth on all the erupted teeth according to WHO criteria. 13 The variable that was measured was the presence or absence of dental caries using the decayed, missing, and filled teeth (dmft) index for primary dentition and Decayed, Missing and Filled Teeth (DMFT) index for permanent dentition. Teachers were requested to assist in communication with the participants. Data and statistical analysis All the data collected were entered into a spread sheet using Microsoft Excel. Descriptive statistical analysis was conducted using means, median, and standard deviation. t-tests were used to compare two means and ANOVA tests were used for comparing more than two means. Significance was tested using the Chi-square test and was set at p <0.05. All the dmft/dmft scores for disabilities and different age categories were ranked in a descending order and the top one-third were analysed independently to determine the Significant Caries Index (SiC). 14 The independent variables that were analysed in the study were included in the demographic profile of age, gender and disability of the participants. The dependent variable analy-

3 310 > Table 1: Number and percentage of participants by disability, gender and mean age (SD) Disability (n=)% Cerebral palsy (n=163) 8.5% Hearing impaired (n=99) 11.2% Learning disability (n=171) 19.4% Mental disability (n=449) 50.9% Total (n=882) 100% Male (n=)% (n=106) 65.0% (n=58) 58.6% (n=130) 76.0% (n=279) 62.1% (n=573) 65.0% Female (n=57) 35.0% (n=41) 41.4% (n=41) 24.0% (n=170) 37.9% (n=309) 35.0% Mean age (SD) 9.7 (2.41) 9.2 (4.34) 10.0 (1.70) 13.0 (3.35) 10.5(3.44) Figure 1: Dental caries prevalence and untreated caries in primary dentition by disability % Caries prevanlence % Untreated caries Cerebral palsy Hearing impaired Learning disability Mental disability d m f dmft the University of the Witwatersrand Ethics Committee with the ethics clearance certificate (Ethics Clearance Certificate number M110834) and from the Gauteng Department of Education. RESULTS Demographics Eight-hundred-and-eighty-two children were examined with a mean age of 10.5 (SD 3.4); age range three to 18 years old; [65% (n=573) males and 35 % (n=309) females]. There were 23 (2.6%) children in the 3-5 years age group, 41 (4.6%) in the six-years-old age group,189 (21.4%) seven to nine years old age group, 289 (32.8%) years old age group, 200 (22.7%) years old age group and 140 (15.9%) 16 and above years old age group. Table 1 indicates the mean number of participants by gender, disability and mean age. More than 50% of the participants were mentally disabled and nearly equal proportions of participants had learning disability and cerebral palsy. When the disabilities were analysed according to gender, males dominated for all the groups assessed. Dental caries status in primary dentition The prevalence of dental caries in primary teeth was 27.55% with no significant difference between males and females (p>0.05). Figure 1 provides information on the caries prevalence and untreated caries in the primary dentition of the participants in each of the disabilities. The lowest caries prevalence was found in the learning disability group (7.02%) and the highest was found in the cerebral palsy group (56.44%) (p=0.000 Chi-square test) Figure 2: d,m, f and dmft components by disability. sed in the was dental caries as measured using dmft/dmft index and caries prevalence. The unmet treatment needs (UTN) were calculated by the formula d/d+f for primary dentition and D/D+F for the permanent dentition. 15 Ethical considerations Permission to undertake the current study was granted by Table 2: Number, mean, standard deviation (SD), d, m, f and dmft by age and disability Disability Age group d m f dmft Cerebral palsy (n=18) 3-6 years 1.83 (2.33) 0.78 (1.83) 0.39 (1.04) 3.00 (3.61) (n=58) 7-9 years 2.66 (2.62) 0.66 (1.93) 0.21 (0.49) 3.53 (3.05) Hearing impaired (n=30) 3-6 years 2.33 (3.25) 0.70 (1.37) 0.37 (1.40) 3.40 (3.87) (n=33) 7-9 years 1.73 (2.63) 1.06 (2.25) 0.18 (0.58) 2.97 (3.17) Learning disability (n=0) 3-6 years * * * * (n=34) 7-9 years 0.88 (1.75) 0.35 (0.77) 0.15 (0.61) 1.38 (2.29) Mental disability (n=16) years 1.75 (3.17) 1.06 (3.23) 0.00 (0.00) 2.81 (4.51) (n=64) 7-9 years 1.59 (1.95) 0.89 (2.62) 0.42 (1.63) 2.90 (3.43) * No participants available in the age group Cerebral palsy Hearing impaired Learning disability Mental disability 0.84 Untreated caries remained high across all the disabilities regardless of the caries prevalence rate (see Figure 1). The dmft scores for the primary dentition per disability are shown (see Figure 2). Table 2 provides information about the dmft status by age categories within each disability. The data illustrates that in the primary dentition, the mean dmft score was highest in the seven to nine year age group of the cerebral palsy group (dmft=3.53), followed by the hearing impaired three to six year old group (dmft=3.40). The lowest dmft (1.35) was found in the seven to nine year olds in the learning disability group. Dental caries status in permanent dentition In the permanent dentition, the dental caries prevalence for the whole sample was 33.56% and Figure 3 provides information on the caries prevalence and the untreated caries in the permanent dentition of the participants in each of the disability groups. The results show that the lowest dental caries prevalence was found in the hearing-impaired group (18.18%) and the highest was found in the learning-disability group (41.52%) (p=0.000). However, there were generally high levels of untreated dental caries regardless of the type of disability. Table 3 provides information regarding the DMFT status by age category within

4 / SADJ Vol 67 No. 7 < 311 each disability. The data shows that the mean DMFT was highest (1.86) in the 16 and above age group in the mental disability group, followed by the 13- to 15-yearold hearing impaired group (1.75). The lowest DMFT score (0.23) was among the 10- to 12-year-old hearing impaired group. When the DMFT scores for the different age categories per disability were compared, a significant difference was found among the scores of the 10 to 12 year olds (p=0.0009), and no significant difference was noted among the 13- to 15-year-old groups in all the disabilities (p=0.58) Table 3: Number, mean (SD), D, M, F and DMFT by age and disability Mean (SD) DMFT by age and disability Disability Age group D M F DMFT Cerebral palsy (n=69) years 0.35 (0.94) 0.04 (0.27) 0.07 (0.31) 0.46 (1.11) (n=17) years 0.41 (1.46) 0.00 (0.00) 1.12 (1.80) 1.53 (2.43) Hearing impaired (n=13) years 0.15 (0.55) 0.08 (0.28) 0.00 (0.00) 0.23 (0.60) (n=8) years 1.12 (1.81) 0.63 (1.77) 0.00 (0.00) 1.75 (3.24) (n=15) 16 & over 0.20 (0.77) 0.27 (0.59) 0.00 (0.00) 0.47 (0.92) Learning disability (n=96) years 0.82 (1.27) 0.30 (0.84) 0.22 (0.86) 1.34 (2.06) (n=41) years 0.59 (1.16) 0.14 (0.57) 0.12 (0.40) 0.85 (1.74) Mental disability (n=111) % Caries prevanlence % Untreated caries years 0.48 (1.06) 0.12 (0.57) 0.06 (0.42) 0.66 (1.40) (n=134) years 0.87 (1.55) 0.18 (0.71) 0.17 (0.69) 1.22 (1.86) (n=124) 16 & over 1.16 (1.92) 0.15 (0.58) 0.55 (1.90) 1.86 (2.86) Cerebral palsy Hearing impaired Learning disability Mental disability Figure 3: Dental caries prevalence and untreated caries in permanent dentition by disability. and this indicates that a minority group within this sample carries the burden of the disease. In simple terms, the distribution of dental caries among the CSHCN in this study was found to be skewed. DISCUSSION It is clear from the analysis of the current data and the comparisons made with other published studies from developing and developed countries that dental caries prevalence rates among CSHCN vary by disability, age group and dentition primary and permanent. This cross-sectional study on the dental caries status of special needs children is the first of its kind in South Africa and may serve as an important reference for the planning of oral health services for this group. Comparison with National Children s Oral Health Survey (NCOHS) The NCOHS results form an important reference document that is used for the planning of oral health services for children in South Africa. The data obtained for this study was re-arranged in the categories used for the NCOHS data, which are similar to WHO reporting formats. 13 For ease of comparison with the non-disabled population and for standardisation, additional data analysis was conducted using the WHO age groups. Table 4 displays the dmft/dmft results of the overall sample (n=203) and the NCOHS results as published by Van Wyk et al. 29 in the WHO age formats. In general no significant difference was found when the dmft/dmft for CSHCN and NCOHS were compared except in the hearing impaired group ages four to five and six both primary dentition year olds, where significantly higher dmft scores (3.58 vs. 2.4; 3.85 vs. 2.9; p<0.05) were found. This was also significant for the permanent dentition in the cerebral palsy group for the 15-year olds, where the DMFT score was 2.43 for cerebral palsy against 1.9 (NCOHS) (p<0.05). Significant caries index Table 5 provides information on the dmft/dmft and SiC in primary and permanent dentition of the different disability groups. In both dentitions and all the disability groups, the SiC scores were higher than the overall dmft/dmft scores Demographic profile The majority of the children in this study were males (65%). Newacheck et al. 16 in the USA reported that boys are onethird more likely to have a special need than are girls. Other studies on special needs children have also shown significantly high proportions of male participants. 10, 17, 11 However, it must be noted that according to the Statistics South Africa Census, there was no difference in the prevalence of disabilities between males and females in South Africa. Thus, the gender bias in the cohort of the current study was not consistent with the census findings of Table 4: Mean dmft/dmft in comparison with National Children s Oral Health Survey dmft/dmft Age 4-5* 6* NCOHS S. NEEDS GROUP * Primary dentition Table 5: dmft, DMFT and SiC per disability dmft/dmft Disability dmft SiC DMFT SiC Cerebral palsy Hearing impaired Learning disability Mental disability

5 312 > Dental caries prevalence In this study cohort, dental caries prevalence for primary dentition and permanent dentition was found to be 27.55% and 33.56% respectively with no significant difference between males and females. Several studies 11, 19 in other developing countries have reported higher levels of dental caries experiences in special needs children when compared with the findings of the current study. A study 19 conducted in India reported a prevalence of 95.9% and 89.1% in primary and permanent dentition respectively. The lower dental caries prevalence in the current sample could be attributed to improved awareness of oral health by the caregivers in the schools, as some of the schools had already been previously visited by the COHOP team from the University of the Witwatersrand. The authors of the Indian study reported that their cohort consumed high cariogenic foods in between meals and the majority of subjects had never been to a dentist before due to the lower socioeconomic status of the parents/caregivers, which resulted in underutilisation of oral health facilities. 19 In contrast, many of the special needs facilities visited during this study appeared to have well-structured healthy diet plans. Similarly, Shyama et al., 20 who also recorded higher caries prevalence in Kuwait than we obtained in this study, reported that the participants in the study were not institutionalised, but were living at home where diet was presumably unregulated and may have been cariogenic. When this study results were compared with those from studies in developed countries, the results were found to be similar to results reported by Pezzementi et al. 21 and significantly lower than those findings reported by De Jongh et al. 22 Dental caries prevalence among the different disabilities in this study revealed that the cerebral palsy and hearing impaired groups had higher (56.44% and 42.42% respectively) dental caries prevalence in the primary dentition compared with the learning disability and mental disability groups (7.02% and 21.60% respectively). The possible reason for the high prevalence in the cerebral palsy and hearing impaired groups includes the fact that cerebral palsy children have problems with dexterity, psychomotor function and coordination which affect their oral hygiene care practices. The higher caries prevalence figures reported for the hearing impaired group in this study sample could be attributed to factors such as little or no access to oral health education; no caregiver assistance for tooth brushing; poor diets; poor oral hygiene; and poor attitude to oral care. The low dental caries rates in the mental disability group is possibly due to the children being in a controlled environment where there was evidence of previous exposure to oral health programmes. The prevalence in the learning disability group should be interpreted with caution as this group did not have participants in the ages of three- to six years. In this study, the highest dental caries prevalence in the permanent dentition was 41.50% in the learning disability group, followed by 36.80% in the mental disability group. Bardow et al. 23 reported that people with severe mental disability are susceptible to oral disease due to a lack of motivation, poor oral hygiene, dental phobia, difficulty in accessing health care facilities and side effects of psychiatric medications such as dry mouth (xerostomia). Observation of patients in this study supports the findings reported by Bardow et al. 23 In this cohort, the dental caries prevalence in the cerebral palsy group aged six, 12 and 15 was (61.11%, 11% and 14.48%) respectively compared with the findings of Huang et al. 17 in Taiwan, who reported a dental caries prevalence of 84,60%, 66,60% and 76.66% in six, seven- to 12 and 13- to 18 year olds respectively. The 11% and 14.48% dental caries prevalence in the current cohort should be interpreted with caution owing to the small number of participants in the particular age groups ( n=18 and n=7) in the 12- and 15-year-old age groups respectively. The high prevalence rates reported by Huang et al. 17 are similar to the general population figures reported by Begramian et al. 24 who conducted a review of epidemiological data from many countries. The authors 24 reported that there was an alarming global increase in the dental caries prevalence in both adults and children in primary as well as permanent dentition. This is contrary to previous, outdated data that suggested a decline in dental caries globally. 25 There was a high level of caries prevalence and UTN in the cerebral palsy group, followed by the hearing impaired group in the primary dentition, and in the permanent dentition the hearing impaired group had the highest UTN. These results are similar to the studies, 26, 27 which reported that CSHCN are more likely to have UTN for dental care than those without special need. Kane et al. 28 reported that UTN for routine medical care was a strong predictor of a UTN for dental care. Hence, the relationship between UTN for dental care and UTN for routine medical care is important and interdisciplinary collaborations together with referral systems among medical and dental care should be encouraged. The higher UTN found among the different disabilities in this study is possibly due to the difficulty in accessing oral health services, transport cost, fear of dental treatment which may make the children un cooperative and difficult to manage on the dental chair, and long waiting lists for treatment under general anesthetic. Mickenautsch et al. 29 found that restorative dental care in the public oral health services of Gauteng in South Africa was limited, with tooth extraction being the predominant treatment provided. Comparison with National Children s Oral Health Survey Prior to undertaking this study, anecdotal evidence suggested that CSHCN had higher dental caries levels than children of the same age groups in the general population. The NCOHS established that dental caries is severe in primary dentition. 30 In comparison with the NCOHS (dmft scores), the dmft in the CSHCN cohort for the four- to five and six year olds was significantly higher than the NCOHS as well as in the 15-year olds, where the cerebral palsy group had a higher DMFT than the same NCOHS age group. Thus the assertion that children with special needs are more prone to having higher levels of oral disease when compared with children of similar age group from the general population appears to have some merit in the South African context. Significant Caries Index The results of this study have shown (see Table 5) that there is an uneven distribution of dental caries burden in all the disabilities. This provides evidence that the major portion of the caries burden is carried by a few individuals within each of the disabilities and has implications in terms of strategies for the treatment and prevention of the disease burden. These findings suggest that in resource poor settings, a targeted/focused approach should be used to manage this

6 / SADJ Vol 67 No. 7 < 313 dental caries burden. 31 The logic is that scarce resources are directed to those individuals/groups that are most in need of treatment. Several published studies 32,33 have used this approach for delivering oral health programmes. However, it must be noted that those with little or no disease burden should not be totally excluded from prevention programmes as Batchelor et al. 34 have shown that children identified as low risk contributed 94% of the new cases of dental caries in the population that was studied. This would be an important caution in a population of children with special needs. Limitations The small numbers of children in the different age groups limits the interpretation of the results. Conclusion Within the limitations of the study, the following conclusions can be made: As whole group, children with special healthcare needs in the current study were found to have lower dental caries levels than children in the general population. When the individual disabilities were analysed, cerebral palsy and hearing impaired children had significantly higher dental caries levels in the primary dentition, and in the permanent dentition the learning disability and mental disability groups were found to have higher levels of caries prevalence. Children with special healthcare needs had higher unmet treatment needs regardless of the type of disability. Acknowledgements Special thanks to Mrs Ralephenya and other staff members of the Department of Community Dentistry. Declaration: No conflict of interest declared References 1. McPherson M, Arango P, Fox H, Lauver C, McManus M, Newacheck P, Perrin J, Shonkoff J, Strickland B. A new definition of children with special health care needs. Pediatrics. 1998; 102: WHO Report on Intellectual disability ncbddd/actearly/pdf/parents_pdfs/intellectualdisability.pdf [online] (accessed Oct 2011) 3. WHO. Deafness and hearing impairment int/mediacentre/factsheets/fs300/en/index.html ] [online] (accessed Jan 2011) 4. WHO Guide for mental retardation, WHO Geneva [online] (accessed Nov 2011) 5. Erickson W, Lee C disability status report: United States. Ithaca, NY: Cornell University Rehabilitation Research and Training Center on Disability Demographics and Statistics; WHO Disease control and priorities related to mental and neurological development and substance abuse disorders.2nd Ed, Oxford press, Switzerland 7. US Surgeon General report. Oral health in America: a report of the Surgeon General. Rockville, Md.: U.S. Public Health Service, Department of Health and Human Services; Horwitz S, Kerker B, Owens P, Zigler E The health status and needs of individuals with mental retardation specialolympics.org/nr/rdonlyres/e5lq5czkjv5vwulp5lx5tm- ny4mcwhyj5vq6euizrooqcaekeuvmkg75fd6wnj62nhlsprlb7tg- 4gwqtu4xffauxzsge/healthstatus_needs.pdf [Online] (accessed Dec 2011) 9. Altun C, Guven G, Akgun OM, Akkurt MD, Basak F, Akbulut E. Oral health status of disabled individuals attending special schools. Eur J Dent. 2010; 4: Oredugba FA, Akindayomi Y. Oral health status and treatment needs of children and young adults attending a day centre for individuals with special health care needs. BMC Oral Health ; 8: Liu HY, Chen CC, Hu WC, Tang RC, Chen CC, Tsai CC, Huang ST. The impact of dietary and tooth-brushing habits on dental caries of special school children with disability. Res Dev Disabil ;31: Cohen, J. Citation classic A coefficient of agreement for nominal scales [online] (accessed Jan 2012) 13. WHO. Oral Health Surveys, Basic Methods.4thed.Geneva: World Health Organization; Bratthall D. Introducing the Significant Caries Index together with a proposal for a new global oral health goal for 12-years-olds. Int Dent J. 2000; 50: Jong A. Dental Public Health ND Community Dentistry, St Louis: CV Mosby Company. 1981: Newacheck PW, Strickland B, Shonkoff JP, Perrin JM, McPherson M, McManus M, Lauver C, Fox H, Arango P. An epidemiologic profile of children with special health care needs. Pediatrics. 1998; 102(1 Pt 1): Huang ST, Hurng SJ, Liu HY, Chen CC. The oral health status and treatment needs of institutionalized children with cerebral palsy in Taiwan. J Dent Sci. 2010; 5: Statistics South Africa Census census01/html/disability.pdf [online] (accessed Dec 2011) 19. Purohit BM, Acharya S, Bhat M. Oral health status and treatment needs of children attending special schools in South India: a comparative study. Spec Care Dentist. 2010; 30: Shyama M, Al-Mutawa SA, Morris RE, Sugathan T, Honkala E. Dental caries experience of disabled children and young adults in Kuwait. Community Dent Health. 2001; 18: Pezzementi ML, Fisher MA. Oral health status of people with intellectual disabilities in the southeastern United States. J Am Dent Assoc. 2005; 136: De Jongh A, van Houtem C, van der Schoof M, Resida G, Broers D. Oral health status, treatment needs, and obstacles to dental care among institutionalized children with severe mental disabilities in The Netherlands. Spec Care Dentist. 2008; 28: Bardow A, Nyvad B, Nauntofte B. Relationships between medication intake, complaints of dry mouth, salivary flow rate and composition, and the rate of tooth demineralization in situ. Arch Oral Biol. 2001; 46: Begramian R, Garcia-Godoy F, Volpe A. The global increase in dental caries. A pending public health crisis. Am J Dent. 2009; 22: Sheiham A. Changing trends in dental caries. Int J Epidemiol. 1984;13(2): Lewis C, Robertson AS, Phelps S. Unmet dental care needs among children with special health care needs: implications for the medical home. Pediatrics. 2005; 116(3):e Al Agili E, Roseman J, Pass A, Thornton B, Chavers S. Access to dental care in Alabama for children with special needs. J Am Dent Assoc. 2004; 13: Kane D, Mosca N, Zotti M, Schwalberg R. Factors associated with access to dental care for children with special health care needs. J Am Dent Assoc. 2008; 139: Mickenautsch S, Frencken JE, van t HM. Atraumatic restorative treatment and dental anxiety in outpatients attending public oral health clinics in South Africa. J Public Health Dent. 2007; 67: Van Wyk PJ, Louw AJ, du Plessis JB. Caries status and treatment needs in South Africa: report of the National Children s Oral Health Survey. SADJ. 2004; 59:238, Messer LB. Assessing caries risk in children. Aus Dent J. 2000; 45: Hausen H, Kärkkäinen S, Seppä L. Application of the high-risk strategy to control dental caries. Community Dent Oral Epidemiol. 2000; 28: Sköld UM, Petersson LG, Lith A, Birkhed D. Effect of schoolbased fluoride varnish programmes on approximal caries in adolescents from different caries risk areas. Caries Res. 2005; 39: Batchelor PA, Sheiham A. The distribution of burden of dental caries in schoolchildren: a critique of the high-risk caries prevention strategy for populations. BMC Oral Health ; 6: