Estimation of tooth agenesis risks between tooth types in orthodontic patients with non-syndromic oligodontia

Oligodontia, a severe type of hypodontia generally characterized as tooth agenesis of six or more permanent teeth excluding third molars, is known to have a multifactorial etiology and the characteristics of orthodontic patients are not fully understood. The aim of the present study was to investigate the risks of tooth agenesis between tooth types of permanent dentition in orthodontic patients with non-syndromic oligodontia. Panoramic radiographs of 292 orthodontic patients (184 females and 108 males) were obtained from one university-based orthodontic clinic and 79 private orthodontic clinics in Japan. Agenesis of permanent teeth excluding third molars was evaluated. Multiple logistic regression analysis was conducted to evaluate the risk of simultaneous tooth agenesis between all tooth type combinations. Significant symmetry of tooth agenesis was observed for all tooth types. Twenty-six tooth type combinations showed a significantly increased risk of simultaneous tooth agenesis [odds ratios (ORs): 1.99⬜14.51], and 15 tooth type combinations showed a significantly decreased risk of simultaneous tooth agenesis (ORs: 0.11⬜0.56). These findings suggest early detection to establish appropriate multidisciplinary treatment planning and prediction of the risk for tooth agenesis of non-syndromic oligodontia.