Association of overjet and overbite with esthetic impairments of oral health-related quality of life

OBJECTIVE: Esthetics is an important part of quality of life and a frequent reason for orthodontic treatment demand. It was the aim of this study to investigate whether esthetic impairments, related to overjet and overbite, can be assessed with an established oral health-related quality of life instrument.

MATERIALS AND METHODS: Data from 1968 participants (age: 16-90 years; 69.8 % female) from three German surveys were analyzed. Esthetic impairments of oral health-related quality of life were measured with four questions of the Oral Health Impact profile (OHIP), which comprise esthetic aspects of oral health-related quality of life. Higher values represent greater esthetic impairment (sum score: 0-16). Overbite and overjet values were categorized (≤ - 1 mm, 0-1 mm, 2-3 mm, 4-5 mm, ≥ 6 mm). The specific impact of each category on esthetic impairment, in relation to the reference category (2-3 mm), was calculated in linear regression analyses. The type of relationship and the specific impact of overbite and overjet were evaluated in regression analyses with fractional polynomials.

RESULTS: Overbite ranged from - 5 to 15 mm (mean: 3.2 mm) and overjet from - 7 to 19 mm (mean: 3.1 mm). Both an increase and a decrease in overjet, in relation to the reference category, resulted in more esthetic-related oral health-related quality of life impairments. However, in this model, only the effect for increased overjet was statistically significant (4-5 mm: + 0.4 OHIP points; ≥ 6 mm: + 0.9 OHIP points). In the regression analysis with fractional polynomials, both an increase and a decrease in overjet resulted in more esthetic impairments, characterized by a U-shaped relationship. No association could be verified for overbite.

CONCLUSION: A substantial increase or decrease of overjet from the reference values is associated with esthetic impairments of oral health-related quality of life, whereas the extent of overbite seems to have no impact on esthetics.