METHODS: School children aged between 13 and 16 years old were randomly selected from a secondary school in Penang. Malay version of Oral Health Impact Profile-14 (OHIP-14) questionnaires were given to the subjects. This questionnaire has 14 questions with seven domains which are functional limitation, psychological discomfort, physical pain, physical disability, psychological and social disability, and handicap. Index of orthodontic treatment need dental health component was used to assess the orthodontic treatment need. Overjet (reversed overjet), open bite, overbite, cross bite, impeded eruption, crowding, defects of cleft lip and palate, Class II and Class III buccal occlusion, present of supernumerary and hypodontia were assessed.

METHODS: The published English version of PIDAQ was pilot tested on 12- to 17-year-old adolescents, resulting in a few modifications to suit the Malaysian variety of English. Psychometric properties were tested on 393 adolescents who attended orthodontic practices and selected schools. Malocclusion was assessed using the Malocclusion Index, an aggregation of Perception of Occlusion Scale and the Aesthetic Component of the Index of Orthodontic Treatment Need, by the subjects (MI-S) and investigators (MI-D). Data were analysed for internal consistency and age-associated invariance, discriminant, construct and criterion validities, reproducibility and floor and ceiling effects using AMOS v.20 and SPSS v.20.

RESULTS: The item Don't like own teeth on video of the Aesthetic Concern (AC) subscale was not relevant to a large proportion of participants (11.7%). Therefore, it was removed and the Malaysian English PIDAQ was analysed based on 22 items instead of 23 items. Confirmatory factor analysis showed good fit statistics (comparative fit index: 0.902, root-mean-square error of approximation: 0.066). Internal consistency was good for the Dental Self-Confidence, Social Impact and Psychological Impact subscales (Cronbach's alpha: 0.70-0.95) but lower (0.52-0.62) though acceptable for the AC subscale as it consisted of only 2 items. The reproducibility test was acceptable (intra-class correlations: 0.53-0.78). For all PIDAQ subscales, the MI-S and MI-D scores of those with severe malocclusion differed significantly from those with no or slight malocclusion. There were significant associations between the PIDAQ subscales with ranking of perceived dental appearance, need for braces and impact of malocclusion on daily activities. There were no floor or ceiling effects.

MATERIALS AND METHODS: This cross-sectional study involved 150 subjects attending the Primary Care Unit with no history of orthodontic treatment. The Dental Aesthetic Index (DAI) with 10 occlusal characteristics were measured on study models. Oral health-related quality of life (OHRQoL) was assessed with the Malaysian version of the Oral Health Impact Profile questionnaire (OHIP-14). The Spearman rank-order correlation coefficient was used to evaluate the relationship between the malocclusion and quality of life.

RESULTS: Significantly weak correlations (r = .176) were found between the DAI and the OHRQoL. Females and the younger age group (12-19 years) tended to score higher on the OHIP-14 than their counterparts. For males, domain 3 (psychological discomfort; r = .462), domain 4 (physical disability; r = .312), domain 7 (handicap; r = .309), and overall score (r = .289) were weak correlates but significant to the DAI compared with females. The older age group showed a significant weak correlation in domain 3 (psychological discomfort; r = .268) and domain 7 (handicap; r = .238), whereas the younger age group showed no correlation with any domain.