Prevalence and patterns of permanent tooth agenesis in patients with nonsyndromic Pierre Robin sequence.

Introduction: Individuals with Pierre Robin sequence (PRS) frequently have tooth agenesis, especially in the mandible. The aims of this study were to characterize permanent tooth agenesis patterns and to determine their prevalence in patients with nonsyndromic PRS.

Methods: Radiographs and clinic charts of 146 children with nonsyndromic PRS were examined for permanent tooth agenesis, excluding third molars, and the tooth agenesis patterns were identified with the tooth agenesis code.

Results: The overall prevalence of permanent tooth agenesis was 32.9% (48 of 146 patients), with about two thirds having bilateral tooth agenesis. No sex or racial predilection was found for tooth agenesis. The most common tooth agenesis pattern was the absence of both mandibular second premolars. Among the children with tooth agenesis, almost half had agenesis patterns involving both mandibular second premolars. Other common patterns of permanent tooth agenesis involved the maxillary lateral incisors and the maxillary premolars.

Conclusions: Symmetric agenesis of individual tooth types occurs much more frequently in the mandible than in the maxilla in patients with nonsyndromic PRS. Bilateral absence of the mandibular second premolars is the predominant pattern of dental agenesis.