Malocclusion traits and oral health-related quality of life in Finnish adults

Aim: The aim of this study was to examine the association of increased overjet, cross-bite/scissor-bite and increased overbite/open bite with oral health-related quality of life (OHRQoL) among Finnish adults using nationally representative data.

Methods: Part of the data from the Health 2000 Survey, Finland, was used in this study. A total of 4711 people were included, representing adults aged ≥30 years. The outcome variable was OHRQoL severity which was measured using the 14-item Oral Health Impact Profile (OHIP-14). Three malocclusion traits (increased overjet, cross-bite/scissor-bite and increased overbite/open bite) were used as explanatory variables. Age group, marital status, education level, income, employment status, having at least one decayed tooth or periodontal pocket ≥6 mm, the number of contacting pairs of teeth, denture status and self-reported general health status were controlled for. A series of multivariable zero-Inflated Poisson (ZIP) models were used to calculate incidence rate ratios (IRR) for the nonzero scores and odds ratios (OR) of having no event.

Results: The weighted prevalence of increased overjet was 8.4%, while it was 23.6% for cross-bite/scissor-bite and 6.7% for increased overbite/open bite. The mean (SE) OHIP-14 (OHRQoL severity) was 2.8 (0.92); the mean score was highest in the pain domain and lowest in the physical and social disability domains. The mean OHIP-14 score was higher in people with increased overjet but not significantly different in people with cross-bite/scissor-bite or with increased overbite/open bite. In multivariate ZIP models, people with increased overjet had a 10% higher OHIP-14 score than people with normal overjet. Increased overjet was associated only with the physical disability domain. Cross-bite/scissor-bite was associated only with the social disability domain, and psychological disability was associated with increased overbite/open bite.

Conclusion: People with increased overjet had significantly poorer OHRQoL than people with normal overjet in a nationally representative population of Finnish adults ≥30 years. Other malocclusion traits were not associated with OHRQoL. However, all three malocclusion traits were associated with either physical or psychological or social disability domains of the OHRQoL.