Anterior crossbite linked to higher tooth loss risk in adults over 40
First large cohort study linking anterior crossbite to molar loss in adults over 40. Implications for preventive orthodontic referrals.
Researchers from Tohoku University in Japan have found that anterior crossbite is associated with increased tooth loss in adults aged 40 and older. The team analysed data from 17,349 participants in the Tohoku Medical Megabank Project Community-Based Cohort Study, categorising them by occlusion type and measuring remaining teeth and posterior tooth loss.
How anterior crossbite affects tooth loss
Adults with anterior crossbite showed a 1.14-fold higher risk of losing molars compared to those with normal occlusion, even after adjusting for age, sex, oral hygiene, caries, periodontal disease and lifestyle factors. Age-stratified analyses revealed that differences in molar retention between occlusal groups became more pronounced in older participants. In contrast, anterior open bite was associated with lower posterior tooth loss, suggesting different malocclusions affect tooth retention through distinct mechanisms.
Why this matters for dental practice
Having fewer than 20 teeth impacts chewing function, nutrition, frailty and healthy life expectancy, making early identification of risk factors important for public health. The study provides the first clear population-level evidence directly linking anterior crossbite to tooth loss. Kento Numazaki, the study's first author, notes that bite alignment may influence long-term tooth retention alongside conventional risk factors like cavities and gum disease. This finding reinforces the importance of regular dental checkups and appropriate orthodontic evaluation as preventive measures for tooth retention in older adults.
Frequently asked questions
Is anterior crossbite associated with tooth loss?
Yes. A study of 17,349 Japanese adults aged 40 and older found that anterior crossbite was associated with a 1.14-fold higher risk of molar loss compared to normal occlusion, after adjusting for age, sex, oral hygiene, caries, periodontal disease and lifestyle factors.
How does anterior open bite affect tooth loss risk?
Anterior open bite showed the opposite relationship: adults with open bite had lower posterior tooth loss compared to those with normal occlusion, suggesting different malocclusions influence tooth retention through distinct mechanisms.
What did the Tohoku study measure?
The study categorised 17,349 adults aged 40 and older into four occlusion groups (normal, anterior open bite, anterior crossbite, combined malocclusion) and assessed whether they had 20 or fewer remaining teeth and posterior tooth loss.
Why is anterior crossbite tooth loss important for dental health?
Having fewer than 20 teeth affects chewing ability, nutrition, frailty and healthy life expectancy. The findings suggest that orthodontic assessment and treatment may help preserve teeth alongside traditional preventive measures.
