Patients with underbites may face a higher risk of losing their teeth, highlighting the importance of orthodontic care in helping preserve natural teeth. The study was recently published in Clinical Oral Investigations.
Furthermore, an anterior crossbite may be linked to posterior tooth loss, while an open bite may be associated with a lower rate of tooth loss, the authors wrote.
“Identification of anterior malocclusion types, particularly anterior crossbite, may help identify individuals at higher risk for tooth loss,” wrote the authors, led by Dr. Kento Numazaki of the Tohoku University Graduate School of Dentistry in Japan (Clin Oral Investig, January 8, 2026, Vol. 30:43).
The study sought to investigate the relationship between anterior malocclusions and tooth loss-related outcomes in a large, community-based sample of adults in Japan. It used cross-sectional data from 17,349 participants age 40 and older enrolled in the Tohoku Medical Megabank Cohort Study, a long-term Japanese research project involving more than 150,000 people combining genomic, multiomics, and lifestyle data to advance healthcare, between 2013 and 2017, they wrote.
Overjet and overbite were measured with a periodontal probe by assessing the distance between the maxillary and mandibular right central incisors in occlusion. Participants were then classified as having a normal occlusion, an anterior open bite, an anterior crossbite, or a combined malocclusion. Outcomes included the number of remaining teeth and the presence or absence of posterior tooth loss.
Three analytical models were used:
- A univariate model (model 1)
- A model adjusted for age and sex (model 2)
- A fully adjusted model including age, sex, body mass index (BMI), active caries, periodontal disease severity, oral hygiene status, hypertension, diabetes, smoking, alcohol use, and educational attainment (model 3)
Across all models, participants with an open bite consistently showed a lower prevalence of posterior tooth loss than those with normal occlusion (model 1: prevalence ratio [PR] 0.76; 95% confidence interval [CI], 0.66 to 0.87; model 2: PR 0.82; 95% CI, 0.72 to 0.93; model 3: PR 0.79; 95% CI, 0.69 to 0.9), they wrote.
In contrast, an anterior crossbite was associated with a higher prevalence of posterior tooth loss in model 2 (PR 1.15; 95% CI, 1.08 to 1.21) and model 3 (PR 1.14; 95% CI 1.07 to 1.2), while no significant differences were found between the combined malocclusion and normal groups. Sensitivity analyses showed similar results, with an open bite linked to a lower prevalence of molar loss (rate ratio [RR] 0.65; 95% CI, 0.57 to 0.73), and an anterior crossbite linked to a higher prevalence of molar loss (RR 1.12; 95% CI 1 to 1.27). After full adjustment, a crossbite was associated with fewer remaining teeth, primarily due to posterior tooth loss.
However, the study had limitations. This was a cross-sectional study, so causality between malocclusion and tooth loss could not be determined, the authors added.
“These findings suggest that the type of malocclusion is associated with tooth loss and supports the potential role of orthodontic treatment in tooth preservation,” Numazaki and colleagues concluded.
