Association of anterior crossbite and open bite with the number of remaining teeth: A cross-sectional study from the Tohoku medical megabank cohort.

OBJECTIVES

Malocclusion, particularly anterior crossbite and open bite, contributes to abnormal occlusal stress distribution, potentially leading to tooth loss. We examined the association between anterior malocclusions and tooth loss-related outcomes in a large-scale, community-based sample of Japanese adults.

MATERIALS AND

METHODS

This cross-sectional study targeted 17,349 participants aged ≥ 40 years from the Tohoku Medical Megabank Cohort Study (2013-2017). Based on overjet and overbite, participants were classified into normal occlusion (n = 16,790), anterior open bite (n = 177), anterior crossbite (n = 348), and combined malocclusion (n = 34). Outcomes included ≤ 19 remaining natural teeth and posterior tooth loss. Adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) were calculated using modified Poisson regression models.

RESULTS

The crossbite group demonstrated a higher prevalence of ≤ 19 remaining teeth (PR, 1.48; 95% CI, 1.04-2.10) and posterior tooth loss (PR, 1.14; 95% CI, 1.07-1.20) than the normal group; the open bite group exhibited a lower prevalence of posterior tooth loss (PR, 0.79; 95% CI, 0.69-0.90). Heatmap analysis revealed lower molar tooth retention in the crossbite group and higher retention in the open bite group.

CONCLUSIONS

Anterior crossbite is associated with increased posterior tooth loss, whereas open bite shows a weaker association. These findings suggest that specific anterior malocclusions may be linked to reduced tooth retention.

CLINICAL RELEVANCE: Identification of anterior malocclusion types, particularly anterior crossbite, may help identify individuals at higher risk for tooth loss. Orthodontic management of anterior crossbite might support posterior dentition preservation and long-term oral function.