Introduction
We examined the role of adolescent orthodontic patients’ psychological well-being attributes (self-esteem, general body image, and positive and negative affects) and the clinical indicators of dental esthetics (orthodontists’ ratings on the Index of Orthodontic Treatment Need-Aesthetic Component [IOTN-AC]), and their changes from pretreatment to posttreatment as predictors of the psychosocial impact of dental esthetics.
Methods
In this prospective longitudinal study, 1090 adolescent orthodontic patients seeking treatment at the Stomatological Hospital of Chongqing Medical University in China (mean age, 14.25 years; SD, 2.03 years) were assessed before treatment, and 68.99% (n = 752) were assessed after treatment. All subjects completed a questionnaire measuring psychological well-being attributes and 3 components of the Psychosocial Impact of Dental Aesthetics (perceptive, cognitive-affective, and social-functional). Clinical indicators of dental esthetics were measured by 3 orthodontists using the IOTN-AC.
Results
Substantial enhancement from pretreatment to posttreatment was found in all 3 Psychosocial Impacts of Dental Aesthetics components, confirming the positive effects of orthodontic treatment on oral health-related quality of life. Psychosocial impact of dental esthetics at baseline and improvement from pretreatment to posttreatment were found to be predicted by the patients’ psychological well-being attributes (self-esteem, general body image, and negative affect) and the clinical indicators (orthodontists’ rating on the IOTN-AC) at baseline, as well as their pretreatment to posttreatment change. Psychological well-being attributes had comparable or greater contribution to the Psychosocial Impact of Dental Aesthetics at baseline as well as greater improvement after treatment than the clinical indicators. These biopsychological models explained 29% to 43% of the variances in psychosocial impacts of dental esthetics outcome at baseline and about 33% of the variance in pretreatment to posttreatment improvement.
Conclusions
This study establishes a biopsychological model for understanding the psychosocial impact of dental esthetics and its improvement after orthodontic treatment among adolescent orthodontic patients. The findings highlight the importance of psychological parameters in orthodontic research and clinical practice.
Highlights
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This prospective longitudinal study establishes 2 biopsychologic OHRQoL models.
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Three components of PIDA improved after treatment.
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Dental esthetics had a strong impact on PIDA.
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Psychological well-being had a comparable or greater contribution to PIDA than clinical indicators.
The psychosocial impact of dental esthetics, an important component of oral health-related quality of life (OHRQoL), has received growing interest in orthodontic research during the past 2 decades. Growing evidence has shown that OHRQoL could benefit from orthodontic treatment, and these improvements were mostly related to the psychosocial impact of dental esthetics. Patients reported significant pretreatment to posttreatment improvements in dental appearance satisfaction, facial and tooth dominant body image, and socio-emotional aspects of well-being.
Understanding factors affecting OHRQoL among adolescents is important for optimizing the effects of orthodontic treatment. Previous studies have consistently reported that oral biologic health (the malocclusion and its associated poor dental esthetics) exerted a negative impact on OHRQoL among adolescent orthodontic patients. However, the association between malocclusion severity and its psychosocial impact is usually modest. For example, some children have remarkable levels of concern for minor anomalies; paradoxically, others are tolerant of severe occlusal problems. Therefore, researchers turned to other contextual factors that might also influence adolescents’ OHRQoL. Patients’ psychological well-being (low self-esteem and negative affect) has been found to be such a robust contextual factor. Emerging evidence has shown that the impact of malocclusion on OHRQoL is especially substantial in children with low self-esteem and children with negative affect. Thus, patients’ psychological well-being may explain, in part, the modest relationship between malocclusion severity and its psychosocial impact.
However, understanding and assessing the psychosocial impact of dental esthetics among children and adolescents are complex. First, physical and psychological development is highly dynamic during puberty. Although some studies used a longitudinal design to investigate the psychosocial impact of dental esthetics among adolescent patients, most of them regarded the psychological characteristics (self-esteem or psychological well-being) as stable personal constructs, and therefore ignored their developmental features. This imposes a problem in a longitudinal study, since the improvement of OHRQoL after treatment is likely derived not only from the treatment itself but also from patients’ psychological development. Second, according to several biopsychological models for illness, psychosocial impact of a disease usually involves perceptual, cognitive-affective, and social-functional components. In the context of dental esthetics’ psychosocial impact, the perceptual component refers to the mental representation of the patient’s dental appearance; the cognitive-affective component reflects the cognition, attitude, and emotion to the malocclusion; and the social-functional component reflects the potential problems in social situations due to subjective dissatisfaction or undervaluation of dental appearance. However, most studies on the psychosocial impact of dental esthetics exclusively focused on the cognitive-affective component and social-functional component, and therapy, ignoring the perceptual component. However, it was reported that approximately 1 in 7 subjects rated his or her own dental esthetics less favorably than it would appear to be, and this bias in self-perception is associated with patients’ dissatisfaction with their teeth, as well as impairment in their social function. Hence, it is important to evaluate the perceptual component when assessing the psychosocial impact of dental esthetics.
Therefore, using a longitudinal design, we aimed to answer these questions. Do the adolescent patient’s psychological well-being attributes affect the OHRQoL outcomes after considering the contribution of clinical indicators of dental esthetics? If so, to what extent do the psychological well-being attributes affect the OHRQoL outcomes? We aimed to construct biopsychological models for understanding psychosocial aspects of OHRQoL among adolescent orthodontic patients. Specifically, we sought to identify predictive factors that could influence the psychosocial impact of dental esthetics at the pretreatment baseline and its improvement after treatment. Predictor variables included (1) patients’ psychological well-being attributes (self-esteem, general body image, positive and negative affects) at the pretreatment baseline; (2) the clinical indicators of dental esthetics (orthodontists’ ratings on Aesthetic Component of the Index of Orthodontic Treatment Need [IOTN-AC]) at the pretreatment baseline; (3) pretreatment to posttreatment changes in the above psychological well-being attributes; and (4) pretreatment to posttreatment changes in the above clinical indicators of dental esthetics. The outcome variable—the psychosocial impact of dental esthetics—was measured in 3 components: the perceptual component, the cognitive-affective component, and the social-functional component. All predictive and outcome variables were measured at both pretreatment and posttreatment.
Material and methods
The study was approved by the ethics committee of Chongqing Medical University (ECCQMU2010-027) in China. Adolescent patients who attended orthodontic clinics at the Stomatological Hospital of Chongqing Medical University, aged between 11 and 18 years, were recruited into this study. A convenient consecutive sampling approach was used. To minimize the confounding variables, only subjects who would receive labial orthodontic treatment with fixed appliances were recruited at their first visit for orthodontic screening in our hospital. Each subject and at least 1 parent provided written informed consent at the first visit. Subjects were excluded if they had a history of orthodontic treatment, severe dentofacial deformities, or past or current neurologic or psychiatric illness. Subjects were also excluded if they would receive any oral-maxillofacial surgery during their orthodontic treatment. Fifty-two adolescents or their parents declined to participate in this study. Twenty-three subjects dropped out in the middle this study. Twenty-nine patients were excluded from this study because the questionnaires were not completed correctly. Finally, 1090 subjects (402 boys, 688 girls) completed the time 1 assessment (T1, pretreatment), of whom 68.99% (n = 752; 217 boys, 535 girls) completed the time 2 assessment (T2, posttreatment) after their orthodontic treatments. At the T1 assessment, 54.95% of patients (n = 599) had tooth extractions, including premolar extractions (n = 557), incisor extractions (n = 18), and premolar and incisor extractions (n = 24). Demographics of these subjects are presented in Table I .
| T1 | T1 ∗ | T2 ∗ | t † | P † | |
|---|---|---|---|---|---|
| n | 1090 | 752 | 752 | ||
| Sex | |||||
| Boys | 402 | 217 | 217 | – | |
| Girls | 688 | 535 | 535 | – | |
| Age (y) | 14.25 (2.03) | 14.12 (2.00) | 15.81 (2.18) | – | |
| Psychological impact of dental esthetics | |||||
| 1. Perceptual component: discrepancy between orthodontists’ rating and self-rating | 0.05 (0.88) | 0.05 (0.83) | –0.03 (1.02) | 2.24 | 0.025 |
| 2. Cognitive-affective component | 1.67 (0.67) | 1.67 (0.68) | 1.06 (0.83) | 19.95 | <0.001 |
| PIDAQ—dental self-confidence ‡ | 1.63 (0.89) | 1.62 (0.88) | 1.14 (0.97) | 8.867 | <0.001 |
| PIDAQ—psychological impact | 1.63 (1.18) | 1.63 (1.19) | 1.01 (0.90) | 20.01 | < 0.001 |
| PIDAQ—esthetic concerns | 1.76 (1.08) | 1.76 (1.13) | 1.04 (1.03) | 18.61 | <0.001 |
| 3. Social-functional component: PIDA—social impact | 1.31 (1.01) | 1.34 (1.14) | 0.97 (1.05) | 13.33 | <0.001 |
| Dental esthetics | |||||
| IOTN-AC—orthodontists’ rating | 5.19 (1.62) | 5.20 (1.66) | 1.28 (0.85) | 39.41 | <0.001 |
| IOTN-AC—patients’ self-rating | 5.24 (1.94) | 5.24 (2.00) | 1.26 (1.21) | 32.16 | <0.001 |
| General psychological well-being | |||||
| NPS-G | 1.80 (1.15) | 1.78 (1.10) | 1.84 (1.62) | −1.75 | 0.080 |
| SES | 2.26 (1.29) | 2.24 (1.19) | 2.30 (1.55) | −1.54 | 0.12 |
| PANAS | |||||
| Positive affect | 25.39 (5.62) | 25.43 (5.44) | 25.65 (5.11) | −1.16 | 0.245 |
| Negative affect | 23.11 (4.98) | 23.33 (5.04) | 22.83 (5.00) | 1.18 | 0.239 |
∗ Subset of the whole T1 sample who completed the follow-up T2 measures, n = 752.
† t and P values are the results of paired t tests on all predictor and outcome variables in the 752-sujbect sample at T1 and T2.
‡ Reverse scored; higher scores indicate lower dental self-confidence.
Each subject completed clinical examinations and questionnaires at T1 and T2. The T1 measurements were done before the start of orthodontic treatment. The T2 measurements were completed after the orthodontic treatment, specifically during the first 2 weeks after removing the fixed appliances. The T1 measurements were performed during January 2011 and September 2013, and the T2 measurements were completed between March 2012 and September 2015. During the T1 and T2 sessions, 1 of the 2 trained investigators introduced all questionnaires to the subjects; then the subjects completed the questionnaires independently in an isolated room in the hospital. The questionnaires included 4 sections.
Demographics were recorded: age, sex, ethnicity, parental education, household income, height, weight, date of birth, student identification, and patient number. Date of birth, student identification, and patient number were used to permit matching of T1 and T2 surveys while ensuring anonymity.
Clinical indicators of dental esthetics were evaluated using IOTN-AC by 3 experienced orthodontists (X.D., Y.-J.W., Y.W.) who had received training in the West China College of Stomatology at Sichuan University, and the calibration protocol was similar to the one reported previously. The kappa coefficients were 0.90 and 0.91 among the 3 orthodontists for pretreatment and posttreatment ratings, respectively. The perceptual component of psychosocial impact of dental esthetics was indexed by the differences between the patients’ self-rating scores and orthodontists’ rating scores on the IOTN-AC (subject’s self-rating scores minus average scores of the 3 orthodontists’ ratings).
The Psychosocial Impact of Dental Aesthetics (PIDA) questionnaire was used to assess the cognitive-affective component and the social-functional component of dental esthetics’ psychosocial impact. It consists of 4 subscales representing dental self-confidence (6 items), esthetic concerns (3 items), psychosocial impact (6 items), and social impact (8 items). In this study, the dental self-confidence, esthetic concerns, and psychosocial subscales were used to assess the cognitive-affective component, and the social impact subscale was used to evaluate the social-functional component. The PIDA questionnaire has been translated into Chinese and back-translated into English by 2 doctoral candidates in English at Southwest University in Chongqing to ensure that the item meanings were as originally intended.
General psychological well-being was assessed using the following questionnaires. The Negative Physical Self-General Appearance subscale was used to assess the dissatisfaction with the patients’ general appearance. The Rosenberg Self-esteem Scale was used to measure the self-esteem. The Positive Affect and Negative Affect Schedule was used to assess the positive affect and negative affect experienced in the past month. Detailed information on these questionnaires and procedures can be found in the Supplementary material (available at www.ajodo.org ).
Statistical analysis
Data analysis was performed using the Statistical Package for the Social Sciences (version 16.0; SPSS, Chicago, Ill). Predictors included adolescents’ biological dental esthetics (orthodontists’ rating on IOTN-AC), self-esteem, general body image, and emotional status. Outcome variables referred to the 3 components of PIDA. Preliminary analyses included missing data assessment and imputation performed on the entire sample and multicollinearity evaluation on measures in each sample. Each variable was compared between the sexes. Correlation analyses between age and each variable were also carried out.
First, predictive models of the 3 components of PIDA were established at T1. (1) Correlation analyses were carried out between predictor variables and outcome variables at T1. This strategy generated estimates of associations between the 3 components of PIDA and each predictor. (2) Three multivariate regression models were established for the outcome variables at T1 with a component of PIDA as the dependent variable in each model. In block 1 of these regression models, age and sex were introduced. In block 2, T1 predictors (orthodontists’ ratings on the IOTN-AC, Rosenberg Self-esteem Scale, Negative Physical Self-General Appearance subscale, Positive Affect and Negative Affect Schedule), which showed significant correlations with the outcome variables, were included. These models were established to evaluate the combined and unique effects of the predictors, independent of patients’ demographics that were controlled in block 1.
Second, predictive models were established to understand which factors contributed to the improvements in the 3 components of PIDA from T1 to T2. The outcome variables in this model referred to the improvements in 3 components of PIDA from T1 to T2. (1) To investigate the changes in each variable after treatment, several paired t tests were conducted on all predictors and outcome variables at T1 and T2. (2) Correlation analyses were conducted between outcome variables and dental esthetic improvement (change in orthodontists’ ratings on the IOTN-AC, which was calculated by T1–T2 with higher scores indicating better improvement). (3) Partial correlation analyses were carried out between outcome variables, general psychological well-being at T1 (self-esteem, general body image, positive affect, and negative affect), and their associated changes (T1–T2), after adjustment for dental esthetic improvement. This strategy generated estimates of associations between 3 components of PIDA improvement and general psychological well-being, independent of the improvement of biologic dental esthetics or overlap among those biologic and psychological factors. These analyses were similar to the ones previously reported. Based on these initial tests, only factors that showed significant partial correlations ( P <0.05) with the outcome variables were included in subsequent multivariate regression models. In block 1 of each model, sex served as a covariate, and dental esthetic improvement was included in block 2; T1 measures of general psychological well-being (self-esteem, general body image, positive affect, and negative affect) were included in block 3, and changes in those general psychological factors were included in block 4. These strategies can evaluate the unique effects of T1 predictors and changes in those factors after treatment.
Results
The T1 assessment was completed by 1090 subjects (402 boys, 688 girls; mean age, 14.25 ± 2.03 years; range, 11-18 years). The majority of participants were Han Chinese (96.88%), and the remaining participants were from 5 of 56 Chinese ethnic minorities: Tujia (1.19%), Miao (0.83%), Yi (0.55%), Hui (0.28%), and Man (0.28%). Of those who completed the T1 assessments, 68.99% (n = 752; 217 boys, 535 girls; mean age, 15.81 ± 2.18 years) also completed the T2 assessment. The duration of orthodontic treatment varied between subjects (mean duration, 85.66 ± 9.98 weeks; range, 55-139 weeks). Demographics are shown in Table I . Preliminary analyses showed that girls reported significantly higher scores than boys on the PIDA cognitive-affective components ( t [1088] = 5.25; P <0.001; mean girl, 1.75 ± 0.64; mean boy, 1.53 ± 0.64), and social-functional component ( t [1088] = 6.71; P <0.001; mean girl, 1.50 ± 1.11; mean boy, 1.04 ± 1.06). Age was significantly correlated with the PIDA cognitive-affective scores ( r = 0.09; P = 0.002).
There was no significant difference between patients’ self-rating and orthodontists’ rating on IOTN-AC ( t [1089] = 1.90; P = 0.057). Results from the Spearman correlation analysis between the predictor and outcome variables are shown in Table II . Three components of PIDA significantly correlated with each other ( r : 0.11-0.42; all, P <0.01). Orthodontists’ ratings on the IOTN-AC positively correlated with the PIDA cognitive-affective component ( r = 0.44; P <0.01) and the PIDA social-function component ( r = 0.36; P <0.01), which indicated that poorer dental esthetics was associated with greater psychosocial impact. General body image dissatisfaction and negative affect positively correlated with 3 components of PIDA, and self-esteem negatively correlated with the PIDA cognitive-affective component and social-functional component ( Table II ). These findings indicated that both clinical indicators of dental esthetics and patients’ general psychological factors were associated with PIDA.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | |
|---|---|---|---|---|---|---|---|
| 1. IOTN-AC orthodontists rating | 1 | ||||||
| 2. PIDA perceptual component | 0.03 | 1 | |||||
| 3. PIDA cognitive-affective component | 0.44 ∗ | 0.28 ∗ | 1 | ||||
| 4. PIDA social function component | 0.36 ∗ | 0.11 ∗ | 0.42 ∗ | 1 | |||
| 5. SES | −0.04 | −0.03 | −0.38 ∗ | −0.45 ∗ | 1 | ||
| 6. NPS-G | 0.01 | 0.14 ∗ | 0.25 ∗ | 0.13 ∗ | −0.20 ∗ | 1 | |
| 7. PANAS-positive affect | −0.01 | −0.01 | −0.04 | 0.01 | 0.39 ∗ | −0.03 | 1 |
| 8. PANAS-negative affect | 0.02 | 0.18 ∗ | 0.36 ∗ | 0.18 ∗ | −0.34 ∗ | 0.14 ∗ | −0.46 ∗ |
Since both biologic dental esthetics and general psychological factors were associated with the cognitive-affective and social-functional components of PIDA, multivariate regression analysis was carried out to investigate the influence of these predictors on the cognitive-affective and social-functional components of PIDA. We did not build a model for the perceptual component of PIDA since there was no significant correlation between the perceptual component and orthodontists’ ratings on the IOTN-AC. This finding indicated that the perceptual component of PIDA was mainly related to adolescents’ psychological characteristics rather than biologic dental esthetics. In the multivariate model of the PIDA cognitive-affective component ( Table III ), after adjustments for age and sex (in block 1), orthodontists’ ratings on the IOTN-AC, self-esteem, body image dissatisfaction, and negative affect (in block 2) explained significant variances in patients’ PIDA cognitive-affective scores. Overall, the predictors explained significant variance ( R 2 = 0.43 [F (6, 1083) = 137.21; P <0.001]) in the criterion. In the multivariate model of the PIDA social-functional component, after adjustment for sex (in block 1), orthodontists’ ratings on the IOTN-AC and self-esteem (in block 2) explained significant variances in patients’ PIDA social-function scores. Overall, the predictors explained significant variance ( R 2 = 0.29 [F (3, 1086) = 129.29; P <0.001]) in the criterion.
| β | t | P | |
|---|---|---|---|
| Model for PIDA cognitive-affective component | |||
| 1. Block 1 | |||
| Age | 0.05 | 2.02 | 0.043 |
| Sex | 0.02 | 0.66 | 0.508 |
| 2. Block 2 | |||
| IOTN-AC orthodontists rating | 0.33 | 10.96 | <0.001 |
| SES | −0.29 | −11.32 | <0.001 |
| NPS-G | 0.11 | 3.48 | 0.001 |
| PANAS-negative affect | 0.18 | 7.07 | <0.001 |
| F (6, 1083) = 137.21; P <0.001; R 2 = 0.43 | |||
| Model for PIDA social-functional component | |||
| 1. Block 1 | |||
| Sex | 0.10 | 3.63 | <0.001 |
| 2. Block 2 | |||
| IOTN-AC orthodontists’ rating | 0.29 | 10.29 | <0.001 |
| SES | −0.31 | −11.10 | <0.001 |
| NPS-G | 0.05 | 1.43 | 0.154 |
| PANAS-negative affect | 0.01 | 0.26 | 0.797 |
| F (5, 1084) = 78.07; P <0.001; R 2 = 0.29 | |||
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