Dental development in hemifacial microsomia I. Eruption and agenesis

The extent of anomalies and developmental aberrations in hemifacial microsomia (HFM) have not yet been fully delineated. Thus, the developmental pattern of the dentition in patients with HFM remains unclear. This study was conducted to investigate the development of the dentition in subjects with varying degrees of HFM and to compare the affected side with the unnaffected side and with data from control samples. Detailed tracings of the complete dental profile of 60 patients with HFM between the ages of 6 and 24 years were obtained from panoramic radiographs. The degree of development of each tooth was compared to Nolla's stages of tooth calcification, and developmental scores were assigned. The present study demonstrates that in individuals with HFM: (1) tooth development is frequently delayed on the affected side; (2) the mandibular third molar is more frequently missing on the affected than on the unaffected side; and 3) the incidence of missing teeth is higher than in unaffected subjects. A possible linkage between tooth development aberrations and the pathogenesis of HFM is discussed. Hemifacial microsomia (HFM) is a predominantly unilateral malformation of craniofacial structures that develop from the first and second branchial arches. Characteristic features of HFM are the underdevelopment of the mandibular condyle and ramus, the zygoma tic arch and malar bone, and associated soft tissues.1 Asymmetric tooth maturation and tooth agenesis also have been found in patients with HFM (Rushton 1953; Loevy and Shore 1985). However, the extent of dental anomalies in patients with HFM has not yet been fully investigated, and the developmental pattern of the dentition in these patients remains unclear. This study was conducted to determine whether a difference exists in the development of the dentition on the affected side compared with the unaffected side in patients with varying degrees of HFM. In addition, the development of the dentition in patients with HFM was compared to that in the general population.