Frequency and type of ponticulus posticus in a longitudinal sample of nonorthodontically treated patients: relationship with gender, age, skeletal maturity, and skeletal malocclusion

Objectives: The aim of this study was to assess the frequency and type of ponticulus posticus and to evaluate its relationship to gender, chronologic age, skeletal maturity, and skeletal malocclusion. Study Design: The sample included the longitudinal lateral cephalograms of 734 patients (378 males and 356 females) retrieved from the American Association of Orthodontists Craniofacial Growth Legacy Collection. The presence of ponticulus posticus (complete and partial forms) was assessed by visual inspection, and the cervical vertebral maturation method was used to determine the skeletal maturation stage. The presence and type (complete or partial) of ponticulus posticus were assessed by gender, age at first appearance of ponticulus posticus, skeletal maturation stage as determined by the cervical vertebral maturation method, and skeletal malocclusion. Results: The overall prevalence of ponticulus posticus was 12.6% (93 of 734) with complete and partial forms observed respectively in 8.7% (64 of 734) and 3.9% (29 of 734) of the sample. Both forms of ponticulus posticus occurred mainly in the age range of 7 to 13 years (P =.04). No differences were found in groups based on gender, skeletal maturity stages, or skeletal malocclusion (P >.05). However, approximately 90% of ponticulus posticus occurred before and after the circumpubertal stage. Conclusions: Ponticulus posticus should be expected mainly during childhood and the pubertal age. This may support the theory of a genetic cause of this vertebral anomaly.