Hypodontia is the term used to describe the developmental

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1 ORIGINAL ARTICLE Psychosocial impact of hypodontia in children Emma Laing, a Susan J. Cunningham, b Steven Jones, c David Moles, d and Daljit Gill e London, United Kingdom Introduction: The purpose of this cross-sectional study was to determine the psychosocial impact of hypodontia (multiple dental agenesis) in children and the influence of factors such as severity of hypodontia, number of retained deciduous teeth, age, and sex. The implications of hypodontia for affected patients have been poorly investigated; this, in part, relates to the lack of appropriate measurements to assess the impact of oral conditions on quality of life, particularly among children and adolescents. Methods: A total of 123 children (49.6% boys, 50.4% girls; mean age, 13.6 years; SD, 1.6 years) were recruited on the basis of predetermined inclusion criteria to either a hypodontia group or a routine orthodontic group of similar treatment need (index of orthodontic treatment need, dental health component 4 or 5) but without hypodontia. Each patient completed the child perceptions questionnaire and 2 visual analog scales to determine the global effects of hypodontia on esthetics and function. Results: The mean number of missing teeth in the hypodontia group was 4.52 (SD, 3.33). There were no statistically significant differences in child perceptions questionnaire scores (overall or at domain level) or visual analog scores between the hypodontia and the routine orthodontic groups (P.0.05). Univariable linear regression analyses provided some evidence that difficulty with chewing was associated with the severity of hypodontia (P ). Conclusions: In this sample, hypodontia did not appear to affect the psychosocial status of patients any more than other features of a malocclusion measured with the index of orthodontic treatment need, dental health component 4 or 5. Patients with hypodontia did, however, have more difficulty in chewing when the deciduous teeth associated with the missing permanent teeth had been exfoliated. This highlights the possible importance of retaining deciduous teeth in patients with severe hypodontia. (Am J Orthod Dentofacial Orthop 2010;137:35-41) Hypodontia is the term used to describe the developmental absence of at least 1 deciduous or permanent tooth, excluding the third molars. 1 It is the most common dental developmental anomaly 2 and has occurred in humans since at least Paleolithic times. 3 The lack of 1 or 2 permanent teeth, with no associated systemic disorders, is the mildest and the most common phenotype. Hypodontia is more common among persons who are genetically related than in those who are not. 4,5 There is a wealth of research into the prevalence, probable etiology, and dentoskeletal effects of hypodontia, but the social, behavioral, educational, medical, and financial implications for an affected person and his or From Eastman Dental Hospital, University College London Hospitals NHS Trust, London, United Kingdom. a Specialist registrar, Department of Orthodontics. b Senior lecturer, Department of Orthodontics. c Consultant and honorary senior lecturer, Department of Orthodontics. d Senior clinical lecturer, Health Services Research. e Consultant, Department of Orthodontics. The authors report no commercial, proprietary, or financial interest in the products or companies described in this article. Reprint requests to: Emma Laing, Eastman Dental Hospital, University College London Hospitals NHS Trust, 256 Gray s Inn Rd, WC1X 8LD, London, United Kingdom; , laingemma@hotmail.com. Submitted, November 2007; revised and accepted, January /$36.00 Copyright Ó 2010 by the American Association of Orthodontists. doi: /j.ajodo her immediate family have been poorly investigated. The psychosocial impact of hypodontia has received little attention in the literature. Hobkirk et al, 6 in a retrospective study of 451 patients with hypodontia, found that the most common complaints were spacing between the teeth and poor esthetics, and some patients were aware that they had missing teeth. Functional problems because of the reduced surface area of the occlusal table comprised only 8.7% of patients complaints. 6 Facial esthetics and esthetic dentistry have become prominent forces in today s popular culture. Dentofacial appearance can affect interpersonal relationships and perceived qualities such as friendliness, social class, intelligence, and popularity from infancy to adulthood. Attractive children are seen by others as more intelligent and having more positive social behavior, and they receive more positive treatment than their less attractive counterparts. 7 Therefore, deviation from ideal dentofacial esthetics, particularly in children, might adversely affect self-esteem and self-confidence, and attract mockery from peers. 8 It is reasonable to speculate that deviations from ideal or normal dentofacial esthetics could be detrimental to a person s psychosocial well-being. The general assumption follows that less attractive children might experience some psychosocial distress as a result of their condition. 35

2 36 Laing et al American Journal of Orthodontics and Dentofacial Orthopedics January 2010 Orthodontic treatment need and effectiveness of treatment are often assessed by morphologic changes in anatomic parameters such as occlusal indexes and cephalometric measurements. However, these types of normative assessments are not always relevant to patients from a psychological, social, or functional aspect because the demarcation between acceptable and unacceptable occlusion is influenced by idiosyncratic judgement. 9 More recently, there has been an emphasis on oral health-related quality of life (OHRQOL) research, which has evaluated the impact of oral conditions on patients lives and might enable a level of care that is appropriate for each patient. 10 These approaches provide insight into the potential consequences of the condition, beyond clinical parameters, on the day-to-day lives of affected patients. 11 This facilitates the understanding of the condition s importance in the provision of oral health care and can ensure that the best practice guidelines are established. Investigation of children s OHRQOL has been addressed only relatively recently in the literature, probably because of the greater complexity of assessing OHRQOL in children than adults. 12 The psychosocial impact of hypodontia in children has received little attention in the literature to date, and it was our purpose to investigate this area. The null hypotheses for the study were (1) there is no difference in psychosocial status between subjects with hypodontia and those with no hypodontia but with a malocclusion of a similar treatment need as classified by index of orthodontic treatment need (IOTN), dental health component (DHC) 4 or 5; and (2) age, sex, and extent of hypodontia have no effect on psychosocial status. MATERIAL AND METHODS The research proposal was approved by the Joint University College London/University College London Hospitals Committee on the Ethics of Human Research Committee. The subjects were recruited from newpatient orthodontic clinics in a teaching hospital by 1 researcher (E.L) from July 2006 to January 2007, and consecutive patients who satisfied the inclusion criteria were invited to participate. Two groups of participants were recruited: a hypodontia group and an orthodontic group not affected by hypodontia (the routine orthodontic group). The criteria for inclusion in the study were patients between 11 and 16 years of age; IOTN, DHC 4 or 5; and radiographically confirmed hypodontia (for the hypodontia group) or no hypodontia (for the routine orthodontic group). Exclusion criteria were previous orthodontic treatment, associated medical conditions, not accompanied by a parent or guardian, or non-english speaker. Each patient and the parent or legal guardian were given written information outlining the details of the study, and its purpose was explained verbally. If the patient and parent or legal guardian agreed to participate, they were taken to a quiet nonclinical area, where written informed consent was obtained. The following demographic details were recorded: age and sex. A sample size calculation was performed using nquery Advisor software (version 5.0, Statistical Solutions, Saugus, Mass) with data from the first 33 hypodontia patients and the first 10 routine orthodontic patients to be recruited. It was found that, for a chisquare test (with a 0.05 level of significance) to have 80% power to detect a 25% difference in questionnaire scores, 61 subjects were required in each group. Each child filled out a validated self-completed questionnaire, the child perceptions questionnaire (11-14 years) (CPQ) compiled by Jokovic et al 13 at the Faculty of Dentistry, University of Toronto in Canada. The authors consent to use the questionnaire was obtained before the study. The CPQ was developed with orthodontic and pediatric dentistry patients and performed well as a discriminative measure between study group patients and was therefore appropriate for our research question. 13 It was shown to be a valid measure with excellent internal consistency and test-retest reliability. 13 Marshman et al 14 further investigated these parameters and confirmed that the validity and reliability were acceptable for use in an orthodontic population in the United Kingdom. These aspects were therefore not investigated in this study. The CPQ consists of 37 questions divided into 4 health domains: oral symptoms, functional limitations, emotional well-being, and social well-being. The questions cover the child s views and perceived views of peers about his or her dental appearance, and behavioral difficulties at home and at school. The response options and scores for the 37 CPQ questions were as follows: 0, never; 1, once or twice; 2, sometimes; 3, often; and 4, every day or almost every day. After completion of the CPQ, the participants were asked to complete 2 visual analog scales (VAS) related to the appearance and function of their teeth. These comprised 2 horizontal lines, 100 mm long, anchored by word descriptors at each end. The function VAS was anchored with I find it easy to eat and I find it hard to eat ; the appearance VAS had I like the way my teeth look and I hate the way my teeth look at either end. Each patient s score was obtained by using a ruler to measure the distance from the left anchor to where he or she had marked the response. Possible scores ranged from 0 to 100, corresponding to the

3 American Journal of Orthodontics and Dentofacial Orthopedics Laing et al 37 Volume 137, Number 1 distance in millimeters to where the cross was placed. An example was provided to clarify the exercise. Since all questions in both tasks were closed, a box for comments was provided at the end of the questionnaire. Participants were allowed as much time as they needed to complete the CPQ and the VAS, and it was made clear that these were for them to complete on their own, without the assistance of a parent or guardian. On average, the tasks took each child 10 minutes to complete. If the patient and the parent or guardian did not have enough time that day, they were given a stamped, addressed envelope and asked to return the completed CPQ and VAS. It was made clear that the child should complete the exercise at home. Statistical analysis The analysis of the data was carried out by using Statistical Package for the Social Sciences software (version 14, SPSS, Chicago, Ill). The data analysis comprised 2 sections: analysis of both groups, by using descriptive statistics and 2-sample t tests to test for differences in CPQ scores (overall and at domain level) and Mann-Whitney U tests to test for differences in VAS scores. In the second section, analysis was restricted to the hypodontia group to investigate the specific effects of the extent and location of hypodontia on the CPQ and VAS scores. To investigate the effects of retention of deciduous teeth, hypodontia was defined in this study as absolute and relative. Absolute hypodontia was the number of missing permanent teeth, and relative hypodontia was the number of missing permanent teeth minus the number of retained deciduous teeth. These 2 scoring methods enabled the effects of retention of the associated deciduous tooth to be considered. Univariable linear regression analyses were used to identify variables contributing to differences in the total and domain CPQ and the VAS scores. In all regression analyses, the model assumptions were found to be satisfactory. RESULTS All 123 patients in the hypodontia and routine orthodontic groups who were approached agreed to participate; there were no withdrawals. Eleven participants took their questionnaires home to complete them, and they were all returned by mail. The sample comprised 62 hypodontia patients (35 boys, 27 girls) and 61 nonhypodontia patients (26 boys, 35 girls) (Table I). The chi-square test for independent samples showed no statistically significant difference in sex distribution between the groups (P ). The mean age of both groups was 13, with an age range of 11 to 16 years (Table I). Table I. Characteristics of the sample Group Hypodontia (n 5 62) Nonhypodontia (n 5 61) Sex Male 35.56% 26.43% Female 27.44% 35.57% Age (y) Mean SD Minimum Maximum An overall CPQ score was calculated for each child by adding all questionnaire item scores, with a maximum possible score of 148. Scores ranged from 2 to 80, and, for both groups, the scores were approximately normally distributed (Table II). The higher the CPQ score, the more often a child would be affected, and it was inferred that the higher the score, the greater the psychosocial impact. A 2-sample t test showed no statistically significant difference in total questionnaire scores between the hypodontia and the routine orthodontic groups (P ) (Table II). With respect to each of the 4 CPQ domains, 2-sample t tests showed no evidence of any statistically significant differences in mean scores between the 2 groups (Table II). Mann-Whitney U tests for 2 independent samples were performed to investigate any potential differences in median VAS scores for eating and appearance between the groups. However, there was no evidence of any intergroup differences in VAS scores for function or appearance (P and P , respectively) (Table III). In the statistical analysis of the hypodontia group, the mean number of missing teeth per subject was 4.52 (SD, 3.33). The numbers of developmentally missing teeth per sextant and retained deciduous teeth per sextant were recorded. From these data, it was possible to calculate a relative hypodontia score. Thus, the mean absolute hypodontia was 4.52, and the mean relative hypodontia was 2.03 missing teeth per subject (SD, 1.76). There was an approximately even distribution of both mean absolute and relative hypodontia by sextant, but the mandibular middle sextant most commonly had missing teeth (Table IV). The maxillary labial segment had the fewest retained deciduous teeth and was the sextant with the greatest relative hypodontia (Table IV). Univariable regression analyses were performed to establish whether the overall questionnaire scores (dependent variable) of the hypodontia patients were influenced by any of the following factors (independent variables): age, gender, total absolute hypodontia, total relative hypodontia, total absolute hypodontia in the

4 38 Laing et al American Journal of Orthodontics and Dentofacial Orthopedics January 2010 Table II. Summary of the 2-sample t test to compare mean total and domain CPQ scores for the hypodontia and nonhypodontia groups Domain Maximum possible score Hypodontia mean Nonhypodontia mean Mean difference in CPQ scores 95% CI of difference P value Oral symptoms , Functional limitations , Emotional well-being , Social well-being , Total CPQ score , Table III. Results of the Mann-Whitney U test comparing median VAS scores for the hypodontia and nonhypodontia groups Question Group Median score P value VAS eating Hypodontia Nonhypodontia 7.0 VAS appearance Hypodontia Nonhypodontia 60.0 maxillary middle sextant, and total relative hypodontia in the maxillary middle sextant. The maxillary middle sextant was looked at in isolation, because it was thought that hypodontia affecting the maxillary anterior region would lead to greater esthetic impairment and perhaps the most psychosocial impact. There was no evidence of any statistically significant relationships between the total CPQ scores for the hypodontia group and any independent variable described (Table V). Univariable regression analyses were performed for each CPQ domain to investigate the effects of the extent or the location of hypodontia on oral symptoms, functional limitations, emotional well-being, and social well-being (Table V). The only statistically significant relationship was that the functional limitations domain was significantly affected by total relative hypodontia (P ) (Table V). Thus, as total relative hypodontia increased, so did the functional limitations domain score; when more teeth were missing (without retention of their deciduous predecessors), the worse the reported effects on function. The P values for the maxillary middle sextant were not significant (P , P ) (Table V); this suggests that any functional limitations were limited to the teeth in the posterior sextants. To further investigate these findings, post-hoc regression analyses were performed to determine the effects of the extent of hypodontia on the VAS scores (Table V). Because of the findings of the regression analyses for the CPQ scores, it was decided to restrict these analyses to 2 parts: the effect of total relative hypodontia and the VAS score for eating; and the effect of Table IV. Mean absolute and relative hypodontia distributions by sextant in children with hypodontia Absolute hypodontia* Relative hypodontia Sextant Mean 95% CI Mean 95% CI Maxillary right , , 0.40 Maxillary middle , , 0.97 Maxillary left , , 0.34 Mandibular right , , 0.30 Mandibular middle , , 0.60 Mandibular left , , 0.32 Total , , 2.48 *Absolute hypodontia was the number of missing permanent teeth. Relative hypodontia was the number of missing permanent teeth minus the number of retained deciduous teeth. total relative hypodontia in the maxillary middle sextant and the VAS score for appearance. There was a statistically significant relationship between the VAS scores for eating and total relative hypodontia (P ), with the VAS score increasing (ie, worsening function) as the extent of relative hypodontia increased (Table V). DISCUSSION Few previous studies have investigated the psychosocial impact of a developmental defect of the dentition in affected patients in terms of quality of life and selfimage. 10,15 There are no similar studies on which the sample size and selection for this study could be based; hence, the first 33 hypodontia patients and the first 10 nonhypodontia patients recruited were used for the sample size calculation. A similar study by Wong et al 16 investigated the effects of severe hypodontia on OHR- QOL. However, there were no control group in their study, no sample size calculation, and no rationale stated for their choice of 25 subjects. An orthodontic sample was chosen as a control group so that hypodontia patients could be compared with patients with malocclusions of a similar treatment need as classified by the IOTN, rather than a Class I ideal occlusion. Future studies could include an

5 American Journal of Orthodontics and Dentofacial Orthopedics Laing et al 39 Volume 137, Number 1 Table V. Univariable linear regression analyses to establish the effect of the extent of hypodontia on the total CPQ scores, functional limitations domain scores, and VAS scores Dependent variable Independent variable (predictor) ß 95% CI P value Total CPQ questionnaire score Age (per year) , Sex (female) , Total number of missing teeth (absolute hypodontia) , Total relative hypodontia , Total absolute hypodontia, maxillary middle sextant , Total relative hypodontia, maxillary middle sextant , Total functional limitations domain score of CPQ Total absolute hypodontia , Total relative hypodontia 0.731* 0.073, 1.389* 0.030* Number of missing teeth, maxillary middle sextant , Total relative hypodontia, maxillary middle sextant , VAS score for function (eating) Total relative hypodontia 2.809* 0.533, 5.084* 0.016* VAS score for appearance Total relative hypodontia, maxillary middle sextant , For this publication, only the regression for the functional limitations domain was included. *Statistically significant findings. additional comparison group of nonorthodontic subjects with no malocclusion, such as unaffected family members, children attending their general dental practitioner or hospital pedodontic clinics, or local schoolchildren, but this was not the purpose of this study. 15 There is, as yet, no gold standard OHRQOL measure for children or adults. 10 The OHRQOL measures available for children at the time of this study were the child-oral impacts on daily performances and the CPQ. 13,17 The CPQ was chosen for this study because it was specifically designed to investigate the impact of oral conditions during early adolescence, which is characterized by the increasingly important role of peer groups and preoccupation with others view of self. 18 Additionally, at the time of this study, the CPQ had been validated for use in a population in the United Kingdom, whereas the child-oral impacts on daily performances tool had not. The CPQ was originally validated for children between 11 and 14 years of age 13 ; however, patients 11 to 16 years of age were recruited for this study because it was thought that 15- and 16-year-olds would have just as good, or better, comprehension of the questionnaire s components, since cognitive development is age-dependent. 18 In addition, many hypodontia patients come to orthodontic clinics an these ages. It is accepted that this might make our study more difficult to compare with other studies using the CPQ that recruited 11- to 14-yearold patients, but the benefits of this were considered to outweigh the drawbacks. Measures such as the CPQ are useful for comparisons across populations but have limited ability to capture the effects of a particular condition because there is as yet no condition-specific measure for hypodontia. 19 Hence, we used a general oral health measure in this study. A shortcoming of the CPQ is its length, although a 100% response rate was achieved in this study, and all questionnaires were completed correctly. 20 The shortened versions of the CPQ might be more useful in future research, once all psychometric properties of these forms have been tested. 20 VAS were used in this study to supplement the questionnaire findings, by quantifying appearance and function (eating), which are subjective parameters. By using continuous scales, VAS values overcame some shortcomings of categorical scales, and they are sensitive to small changes in the parameter investigated. 21 There were no statistically significant differences between the hypodontia and the routine orthodontic groups for overall CPQ scores (P ), any domain score (P ; P ; P ; P ) (Table II), or VAS scores for eating and appearance (P and P ), respectively (Table III). One might therefore conclude that the 2 groups had no differences in psychosocial impact. However, it is unknown whether the impact experienced by both groups was high or low relative to children without a significant malocclusion. A weakness of cross-sectional studies such as this is that associations are investigated and not causality, so the reasons for the findings are not known. Additionally, a low, medium, or high CPQ score has not been formally quantified to date, so it is unknown what total CPQ score would imply a considerable impact. Jokovic et al, 13 who compiled the CPQ, did not categorize a particular total score as having a specific degree of impact. Similar studies suggest that hypodontia negatively affects patients. For example, Johal et al 22 undertook a prospective cross-sectional study to assess the impact of increased overjets and spaced dentitions on the

6 40 Laing et al American Journal of Orthodontics and Dentofacial Orthopedics January 2010 quality of life of 180 children (ages, years) and their parents, and found that both occlusal traits had a significant negative impact on the children s and parents quality of life compared with the control subjects. Wong et al, 16 in a recent cross-sectional study of OHR- QOL and severe hypodontia in Hong Kong, concluded that severe hypodontia considerably impacts OHRQOL, although no control group was used. The considerable impact was derived from a mean CPQ score for the severe hypodontia group of 29.0 (SD, 16.4) of a potential maximum score of 148. In the current study, the mean CPQ score for the mild, moderate, and severe hypodontia combined was (SD, 16.03) of a potential maximum score of 148. Therefore, in this study, if only patients with severe hypodontia had been included, this may have caused the mean CPQ score to have been higher. If Wong et al 16 had used a control group to compare the results of the hypodontia group, they might have reached different conclusions. A number of reasons might account for why the hypodontia group did not experience a greater psychosocial impact than did the routine orthodontic group. It may be that the routine orthodontic subjects were equally psychosocially affected by their dentition, although for different reasons, and this is worthy of future research. Based on Brook s 1974 classification, 23 the average hypodontia found in this study (4.52; SD, 3.33) was moderate (3-5 missing teeth), and this severity of hypodontia could have been too mild for the patients to have been affected psychosocially by it. Also, adjacent teeth might have erupted into the space left by the missing tooth, giving the illusion that the dentition was intact; the effects of hypodontia might have been camouflaged well and appeared as just mild spacing; and spacing of the dentition is commonly found in the late mixed dentition as the rest of the deciduous teeth eg, the canines are exfoliated. Thus, some subjects in the hypodontia group might not have been affected by visible spacing of the dentition and were unaware of permanently missing teeth. In the analysis of the hypodontia group, univariable linear regression analyses showed no statistical evidence of age, sex, and extent and location of hypodontia affecting overall CPQ scores (Table V). At the domain level, no effect was seen, except for the functional limitations domain that was significantly affected by the total relative hypodontia (P ) (Table V). This implied some evidence that, as relative hypodontia increased, the subject s functional impairment significantly worsened. In other words, as deciduous teeth were lost and not replaced by permanent teeth, the associated spacing increased, leading to functional limitations with eating. This gives some tentative evidence that retention of deciduous teeth would be beneficial for hypodontia patients, at least in terms of function. The P values for the maxillary middle sextant were not significant (P and P ), suggesting that hypodontia in this region did not cause functional limitations (Table V). This implies that functional limitations might be predominantly limited to the teeth in the posterior sextants so that, for example, a missing premolar would make chewing with the posterior teeth more difficult than if a maxillary lateral incisor were missing. The regression analyses for the VAS scores further investigated this and showed evidence of a statistically significant relationship between the VAS scores for eating and total relative hypodontia (P ) (Table V). This agrees with the findings of the CPQ functional limitations domain regression analysis (Table V). There was no evidence of a relationship between the VAS scores for appearance and relative hypodontia of the maxillary middle sextant (P ). Either hypodontia in this area does not affect patients psychosocially or the extent of hypodontia in this sample was too mild or too well camouflaged to affect patients psychosocially. CONCLUSIONS 1. In this sample, there was no difference in the psychosocial status of patients with hypodontia compared with patients with other features of an IOTN, DHC 4 or 5 malocclusion, but not affected by hypodontia. 2. There was also no evidence to suggest that age or sex has any influence on the psychosocial status of either group of patients. 3. There was some statistical evidence to suggest that relative hypodontia has an impact on the functional abilities of the hypodontia patients and that retention of deciduous teeth is beneficial from a functional point of view. 4. This study has implications in understanding the impact of hypodontia on quality of life. Measurement of treatment need and effectiveness should include not only normative assessment but also psychological and social dimensions. We thank Aleksandra Jokovic and his colleagues for permitting us to use the CPQ, all patients and their parents or legal guardians who participated in the study, and the clinicians who allowed us to recruit patients from their clinics.

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