The impact of malocclusion on tooth loss over a 20-year period: Findings from the Population-Based Study of Health in Pomerania (SHIP).

Objective: Research is lacking examining the effect of malocclusion on tooth loss. The aim of this study was to analyze the possible impact of moderate and severe malocclusions on tooth loss over the course of twenty years.

Material And Methods: Of 1269 subjects aged between 25 and 49 years with at least 20 teeth of the population-based Study of Health in Pomerania in Germany, malocclusions were initially assessed according to a German orthodontic index of treatment priority between 1997 and 2001. The available participants were re-examined every 5 years up to 2021. Tooth loss was analyzed in multilevel survival analyses including tooth, jaw and subject level. The models were adjusted for age, sex, marital status, school education and coexisting malocclusions in the same participant.

Results: Among 623 (49 %) participants with orthodontic treatment priority, 201 showed more than one malocclusion feature. Missing, unreplaced teeth as equivalent for hypodontia, increased overjet of 3-6 mm or > 6 mm, deep bite of > 3 mm with gingival contact, and posterior cusp-to-cusp bite were risk factors for tooth loss. Open bite of 1-2 mm, deep bite of > 3 mm without gingival contact, bilateral crossbite, and incisal crowding with ≤1/2 width of lateral incisor were protective against tooth loss.

Conclusions: Given the negative and positive impacts of some malocclusions on tooth loss, other potential detrimental effects on oral health and psycho-social well-being were not considered in this study.

Clinical Significance: This long-term study showed for the first time, that some malocclusions in adults can cause tooth loss and others are protective. This should be weighed in the decision making process for orthodontic treatment.