Craniofacial and dental phenotype of Smith-Magenis syndrome

The aim of this study was to assess and characterize dental and craniofacial findings in individuals with a confirmed diagnosis of Smith-Magenis syndrome (SMS). Extraoral and intraoral examination including dental and craniofacial radiographs and three-dimensional facial photoimaging were performed for 15 cases between ages 4 and 19 years old. Tooth agenesis (13/15 cases) affecting primarily the mandibular second premolars and taurodontism (13/15 cases) were common findings. Dilaceration of the tooth roots was present in one-third of the cases. At least one dental anomaly was present in each case. These findings occur with greater frequency than in the general population (P < 0.001). An age-related increase in decayed and restored teeth was found. Poorer oral hygiene, increased dental plaque, and increased gingival inflammation progressed from childhood to teenage years. Radiographic findings suggest the prognathic appearance is not caused by excessive mandibular growth. Other findings including protrusion of the mandibular anterior teeth, increased bony chin size, and macroglossia were noted, which may contribute to the prognathic appearance. The high prevalence of dental anomalies (>90%) further expands the phenotype and indicates that dental evaluation may aid in the diagnosis of SMS.