Oral health-related quality of life and orthodontic treatment seeking


The aim of this study was to assess oral health-related quality of life (OHQOL) in adolescents who sought orthodontic treatment. A comparison between these adolescents and their age-matched peers who were not seeking orthodontic treatment provided an assessment of the role of OHQOL in treatment seeking.


The sample consisted of 225 subjects, 12 to 15 years of age; 101 had sought orthodontic treatment at a university clinic (orthodontic group), and 124, from a nearby public school, had never undergone or sought orthodontic treatment (comparison group). OHQOL was assessed with the Brazilian version of the short form of the oral health impact profile, and malocclusion severity was assessed with the index of orthodontic treatment need.


Simple and multiple logistic regression analysis showed that those who sought orthodontic treatment reported worse OHQOL than did the subjects in the comparison group ( P <0.001). They also had more severe malocclusions as shown by the index of orthodontic treatment need ( P = 0.003) and greater esthetic impairment, both when analyzed professionally ( P = 0.008) and by self-perception ( P <0.0001). No sex differences were observed in quality of life impacts ( P = 0.22). However, when the orthodontic group was separately evaluated, the girls reported significantly worse impacts ( P = 0.05). After controlling for confounding (dental caries status, esthetic impairment, and malocclusion severity), those who sought orthodontic treatment were 3.1 times more likely to have worse OHQOL than those in the comparison group.


Adolescents who sought orthodontic treatment had more severe malocclusions and esthetic impairments, and had worse OHQOL than those who did not seek orthodontic treatment, even though severely compromised esthetics was a better predictor of worse OHQOL than seeking orthodontic treatment.

There is increasing recognition that oral disorders can have a significant impact on physical, social, and psychological well-being. This has resulted in greater clinical focus on improving quality of life as a major objective of dental care for dental conditions that are not life threatening.

The importance of evaluating oral health-related quality of life (OHQOL) among orthodontic patients relates to the impact of dental esthetics on social acceptance and self-concept. It has been shown that those with malocclusion can develop feelings of self-consciousness and shame about their dental condition or feel shy in social contexts, and also their body self-concept because of facial appearance might be negatively affected. Nevertheless, a malocclusion can be perceived differently by the affected person, and a person’s self-awareness of the malocclusion might not be related to its severity.

Therefore, when evaluating the impact of a malocclusion, it is important to consider the different domains that can be affected and their relationships to personality traits and psychosocial factors. Some people with a severe malocclusion are satisfied with or indifferent to their dental esthetics, whereas others are concerned about minor irregularities.

Assessing the effect of oral disorders and conditions on quality of life can be of great value to researchers, health planners, and oral health care providers. Several instruments have been designed to measure dental outcomes in terms of the impact on quality-of-life of changes in oral health. Among these, the oral health impact profile (OHIP) and its short form (OHIP-14) are widely used. The original 49-item OHIP was developed by Slade and Spencer, based on the OHQOL conceptual model of Locker, derived from the World Health Organization’s International Classification of Impairments, Disabilities and Handicaps. It was designed to be applied to diverse oral conditions. The items in the original 49-item version and in the short form, OHIP-14, are grouped into 7 domains: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. The OHIP and the OHIP-14 were originally developed for use with elderly patients, but both have been successfully used to measure the impact of oral problems in adolescents in the United States, Brazil, Myanmar, and Chile. The Brazilian version of OHIP-14 has shown good psychometric properties, similar to those of the original instrument, when tested in young women and in 12-year-old schoolchildren.

The aims of this study were to assess OHQOL in Brazilian adolescents aged 12-15 who sought orthodontic treatment in the Department of Orthodontics at Rio de Janeiro State University in Brazil and to measure the impacts of malocclusion severity, esthetic impairment, sex, age, and socioeconomic status on their OHQOL. A comparison between these adolescents and age-matched peers who were not seeking orthodontic treatment provided an assessment of the role of OHQOL in treatment seeking.

Material and methods

Permission to undertake the survey was obtained from the Ethics Research Committee of Rio de Janeiro State University. Parents received a letter describing the study and requesting consent for their children to participate.

The sample consisted of 225 adolescents (ages, 12-15 years) divided into 2 groups: the orthodontic group and the comparison group. All 101 children between 12 and 15 years of age who were scheduled for orthodontic treatment evaluation in the Department of Orthodontics of Rio de Janeiro State University in 2006 were eligible to participate in the orthodontic group. Because 9 parents did not allow their children to participate in the study (8.8% loss; 77.7% girls, 22.3% boys), the orthodontic group had a final number of 92 children. The comparison group initially comprised all 124 age-matched children from a public school near the university clinic. Their parents were sent a questionnaire, attached to the consent form, asking whether their children had already sought or undergone orthodontic treatment. Twenty-two children were excluded because they did not return the consent form or reported having had or sought orthodontic treatment. Therefore, the comparison group consisted of 102 children (17.7% of loss; 63.4% girls, 36.6% boys).

This sample size was sufficient to estimate a prevalence of oral impacts of 25% in the comparison group and a difference between this group and the orthodontic group, with a power of 80% at a significance level of 0.05.

Data on variables and their measurement were collected through interviews, self-completed questionnaires, and dental screenings performed by an orthodontist (D.F.). The questionnaires included a measurement of OHQOL, the Brazilian shortened version of the OHIP-14. During the interviews, a measurement of socioeconomic status was used, the Brazil economic classification criteria. This classifies people into 5 socioeconomic categories according to the educational level of the head of the household, consumer goods owned (eg, VCRs, DVDs, color TVs), and access to household help. For our statistical analysis, the 5 socioeconomic categories were divided into high (A and B) and low (C-E) social classes.

After the children were interviewed and had finished filling out the questionnaires, clinical examinations were conducted to assess orthodontic treatment need and dental health status. Malocclusion severity and orthodontic esthetic impairment were measured by using, respectively, the dental health component (DHC) and the aesthetic component (AC) of the index of orthodontic treatment need (IOTN). Esthetic impairment, measured by IOTN-AC was also evaluated by the children themselves (AC self-perception). Dental health status was determined with the decayed, missing and filled teeth index (DMFT) and the World Health Organization diagnostic criteria.

Students in the comparison group were examined in their school’s dental office, under conditions similar to those at the university where the orthodontic group was examined, and by the same orthodontist. The examiner had been determined as being trained in the use of the IOTN index by a researcher (gold standard) with broad experience with this occlusal index (J.A.M.). The gold standard had been previously determined for IOTN assessment during a course at the University of Manchester in the United Kingdom. The training process included examination of 20 plaster casts by both the examiner and the researcher, and subsequent comparison of their results. To assess intraexaminer reliability, 26 children were reinterviewed and reexamined 7 to 10 days after the first assessments (15 from the comparison group and 11 from the orthodontic group).

Statistical analysis

The data were analyzed by using software (version 7.0, StataCorp, College Station, Tex). Simple and multiple stepwise regression analyses, as well as chi-square and t tests, were used to evaluate the effects of esthetic impairment, malocclusion severity, sex, age, and socioeconomic status on OHQOL. Significance levels were set at 0.05. Kappa statistics were used to test the consistency between the examiner’s scores and the gold standard scores, and for intraexaminer reliability. To test the stability and internal consistency of the OHIP-14, the intraclass correlation coefficient (ICC) and the Cronbach reliability coefficient α were used, respectively. For OHIP-14 analysis, ordinal responses were coded from 0 for “never” to 4 for “very often,” and all 14 ordinal responses were summed to produce an overall OHIP score that could range from 0 to 56, with higher scores indicating poorer OHQOL.

IOTN-AC scores range from 1 to 10 and for analytical purposes; subjects with scores greater than 5 were considered to have an esthetic orthodontic treatment need. For the DHC scores (range, 1-5), subjects with scores greater than 3 were considered to have an objective orthodontic treatment need. These determinations of orthodontic treatment needs were based on the cutoff points for index dichotomization of Mandall et al, which had been used in previous studies.


For both the DHC (kappa, 0.70) and the AC (kappa, 0.68) components of the IOTN, the examiner had good agreement with the gold standard. Intraexaminer reliability was very good (kappa, 0.98 for AC [95% CI, 0.96-1.0]; kappa, 0.96 [95% CI, 0.90-1.0] for DHC; and kappa, 1.0 for DMFT), indicating substantial consistency of the clinical measurements. The ICC for the OHIP-14 was 0.97 (95% CI, 0.95-0.99) and the kappa coefficient for the AC self-perception was 0.93 (95% CI, 0.90-1.0). Test-retest reliability values for the OHIP-14 and the AC self-perception were similar between the orthodontic and comparison groups. The internal consistency of the OHIP-14 showed a satisfactory Cronbach coefficient α of 0.73 (95% CI lower limit, 0.68).

Statistically significant differences between the orthodontic and comparison groups were found for socioeconomic status, malocclusion severity, and esthetic impairment. The orthodontic group included more children at the high socioeconomic level and fewer at the low level ( P = 0.002). This group also had significantly higher DHC, AC examiner, and AC self-perception scores on the IOTN, indicating more severe malocclusions and greater normative and self-perceived treatment needs than did those in the comparison group. However, the 2 groups did not differ for age, sex, and dental health status (DMFT). These findings are shown in Table I .

Table I
Distribution of sociodemographic characteristics, and IOTN, DMFT, and OHIP-14 scores
Comparison group Orthodontic group Total
P n (%) n (%) n (%)
Socioeconomic status
A or B 0.002 19 (18.6) 49 (53.2) 60 (30.9)
C 66 (64.7) 41 (44.5) 115 (59.3)
D 17 (16.6) 2 (2.17) 19 (9.8)
Male 0.246 60 (57.7) 46 (50) 106 (54.6)
Female 42 (42.3) 46 (50) 88 (45.4)
Age (mean y) 0.320 13.5 (0.1) 13.2 (0.1) 13.6 (0.1)
DMFT 0.793 1.2 (0.1) 1.7 (0.2) 1.4 (0.1)
IOTN-AC examiner
Score 1-4 0.008 71 (69.6) 47 (51.1) 118 (60.8)
Score 5-7 26 (25.4) 36 (39.1) 62 (32.0)
Score 8-10 5 (4.9) 9 (9.78) 14 (7.2)
IOTN-AC self-perception
Score 1-4 0.000 99 (97.0) 59 (64.1) 158 (81.4)
Score 5-7 3 (2.9) 23 (25.2) 26 (13.4)
Score 8-10 0 10 (10.7) 10 (5.2)
Score 1-3 0.000 76 (74.5) 40 (43.5) 116 (59.8)
Score 4-5 26 (25.5) 52 (56.5) 78 (40.2)
Total sample 102 (52.58) 92 (47.42) 194 (100)

For ratio comparisons of proportions, the chi-square test was used and, for average means, the t test.

Line values refer to mean scores and percentages of standard deviation.

In this study, the OHIP-14 values had an asymmetric distribution in a favorable direction (ie, higher frequency of low OHIP-14 scores indicating relatively high OHQOL), with scores ranging from 0 to 31. In the statistical analysis, OHIP scores were transformed into a dichotomous variable by using a cutoff value of 9, the median for the whole sample (n = 194). Thus, OHIP-14 scores higher than 9 were considered to reflect more negative OHQOL, and those lower than or equal to 9 indicated more favorable OHQOL.

OHIP-14 scores were substantially higher in the orthodontic group, and the girls had significantly higher OHIP-14 scores than did the boys in that group ( P = 0.05). Adolescents who had sought orthodontic treatment also had higher OHQOL scores in all 7 OHIP-14 domains. In both groups, the domains that were most negatively affected were psychological discomfort (35.8%) and psychological disability (38.0%).

Furthermore, severe malocclusion (DHC scores of 4 and 5), normative and self-perceived esthetic impairment (AC scores >5), and poor dental health (DMFT >5) were also statistically associated with more negative OHQOL. No statistically significant associations were found between socioeconomic status, sex, age, and OHQOL. These findings are given in Table II .

Table II
Associations between sociodemographic characteristics, IOTN, DMFT, and OHIP-14
OHIP <9 (higher OHQOL) OHIP >9 (lower OHQOL) Total
P Odd ratio (95% CI) n (%) n (%) n (%)
Socioeconomic position
A or B 1 36 (66.6) 18 (33.4) 60 (100)
C 0.99 1.05 (0.47-2.33) 81 (66.9) 40 (33.1) 115 (100)
D 1.77 (0.46-6.73) 13 (68.4) 6 (31.6) 19 (100)
Male 0.22 1.65 (0.55-2.26) 75 (70.8) 31 (29.2) 106 (100)
Female 55 (62.5) 33 (37.5) 88 (100)
Comparison 0.00 4.66 (1.35-5.70) 84 (82.3) 18 (17.7) 102 (100)
Orthodontic 46 (50.0) 46 (50.0) 92 (100)
IOTN-AC self-perception
Score 1-4 0.00 1 118 (74.7) 40 (25.3) 158 (100)
Score 5-7 4.0 (1.7-9.5) 11 (42.3) 15 (57.7) 29 (100)
Score 8-10 26.6 (6.2-216.1) 1 (10.0) 9 (90.0) 10 (100)
IOTN-AC examiner
Score 1-4 0.00 1 91 (77.7) 26 (22.3) 117 (100)
Score 5-7 2.6 (1.8-6.8) 23 (37.1) 39 (62.9) 62 (100)
Score 8-10 5.11 (3.3-8.7) 7 (53.84) 6 (46.16) 13 (100)
Score 1-3 0.00 3.28 (1.76-3.12) 90 (77.6) 26 (22.4) 116 (100)
Score 4-5 40 (51.3) 38 (48.7) 78 (100)
DMFT 0.05 1.24 (1.0-1.5) 1.2 (0.1) 1.7 (0.2) 1.4 (0.1)
Age (y) 0.08 0.84 (0.62-1.14) 13.7 (0.1) 13.4 (0.1) 13.6 (0.1)
Total 130 (67.0) 64 (33.0) 194 (100)

For ratio comparisons, the chi-square test was used and, for averages, the t test.

Lines values refer to mean scores and percentages.

Multivariate analysis was used to adjust the relationship between orthodontic treatment seeking and OHQOL. All potential confounding variables that showed an association (eg, malocclusion severity, decay experience, and orthodontic treatment needs) with the outcome variable (ie, more severe impact: OHIP-14 score >9) in the bivariate analyses were included in the model. Initially, subjects in the orthodontic group were 4.6 times more likely to report a negative impact on their quality of life than those in the comparison group. After controlling for DMFT, DHC, AC examiner, and AC self-perception, adolescents who sought orthodontic treatment still were 3.1 times more likely to report worse OHQOL than those from the comparison group, who did not seek orthodontic treatment. Severely normative and self-perceived esthetic impairment were stronger predictors of worse OHQOL than treatment seeking ( Table III ).

Apr 14, 2017 | Posted by in Orthodontics | Comments Off on Oral health-related quality of life and orthodontic treatment seeking
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