Objectives <p>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.</p> Materials and methods <p>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 (<i>n</i> = 16,790), anterior open bite (<i>n</i> = 177), anterior crossbite (<i>n</i> = 348), and combined malocclusion (<i>n</i> = 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.</p> Results <p>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.</p> Conclusions <p>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.</p> Clinical relevance <p>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.</p>