Negative self-perception of smile associated with malocclusions among Brazilian adolescents

This study estimated the prevalence of negative self-perception of smile because of occlusion abnormalities and investigated their association according to standard clinical criteria. The sample consisted of 1290 randomly selected Brazilian adolescent boys and girls aged 12-16 years. The outcome of interest was dissatisfaction with smile, and data were collected using a standardized questionnaire. Occlusion characteristics were assessed using the dental aesthetic index (DAI). The other study variables were gender, age, and use of dental services. A chi-square test and Poisson multiple regression were used for statistical analysis. Of the 1290 students interviewed and examined, 539 (41.8 per cent) were dissatisfied with their smile; of these, 373 (69.2 per cent) assigned their dissatisfaction to the presence of an occlusal abnormality, and 166 (30.8 per cent) reported reasons other than occlusal abnormalities for their negative self-perception of their smile. In multivariate analysis, the following variables were associated with the outcome of interest: maxillary anterior irregularity [prevalence ratio (PR) = 1.40; 95 per cent confidence interval (CI) = 1.29-1.80], incisal spacing (PR = 1.37; 95 per cent CI = 1.19-1.57), vertical open bite (PR = 1.34; 95 per cent CI = 1.15-1.55), mandibular anterior irregularity (PR = 1.29; 95 per cent CI = 1.14-1.46), permanent anterior teeth missing (PR = 1.21; 95 per cent CI = 1.05-1.39), and incisal diastema (PR = 1.14; 95 per cent CI = 1.01-1.31). The negative self-perception of smile was statistically associated with severity of occlusal disorders according to the DAI scores, which suggests that self-perception should be used together with standard clinical criteria when decisions about orthodontic treatments are made in public health care systems.