Purpose: The purpose of this study was to explore the association of mandibular incisor agenesis with other dental anomalies in Japanese orthodontic patients.
Methods: A total of 52 subjects with 1 or 2 congenitally missing permanent mandibular lateral incisors (group A) were selected and divided into group 1a (26 subjects with 1 lateral incisor missing) and group 2a (26 subjects with 2 lateral incisors missing). Fifty two sex-matched subjects without agenesis of the mandibular lateral incisor served as controls (group C). Radiographs, study models, and medical and dental records were used to identify anomalies of teeth.
Results: The prevalence rate of agenesis of teeth other than the mandibular lateral incisors and third molars was significantly increased in group A. Agenesis of the maxillary second premolars was significantly increased in groups 2a and A. Significantly increased prevalence rates of symmetrical tooth agenesis, with third molars excluded, and third molar agenesis were observed in group 1a and A.
Conclusions: Japanese subjects with agenesis of 1 or 2 permanent mandibular lateral incisors have significantly increased prevalence rates of other permanent tooth agenesis and symmetrical tooth agenesis.