Influence of overjet and overbite on soft tissue profile in mature adults: A cross-sectional population study.

INTRODUCTION: The aim of this study was to explore the association of soft tissue profile and severity of overbite and overjet in a large adult population. METHODS: The study population consisted of 1630 adults (age, 46 years; 712 men, 919 women), all part of the Northern Finland Birth Cohort 1966. A clinical examination was performed on all subjects, including recording of overjet and overbite, and digital facial (frontal and profile) photographs were obtained. A multivariate regression model was developed to study the correlation of soft tissue measurements with overjet and overbite, considering the effect of sex. RESULTS: The regression model explained approximately 30% of the variability in overjet in our sample and approximately 22% of the variability in overbite. Overjet was related more significantly to upper and lower anteroposterior lip position, and upper and lower facial height (P <0.05). Overbite showed a stronger association with anteroposterior position of the lower lip, pogonion, and soft tissue B-point (P <0.05). CONCLUSIONS: Soft tissue profile was weakly to moderately correlated with severity of overjet and overbite in the entire sample. However, in subjects with negative overjet (mandibular prognathism), this association was highly significant.