Hemifacial microsomia is a condition affecting primarily aural, oral, and mandibular development. The phenotype varies from mild to severe, it is usually limited to one side, but bilateral involvement also occurs (Gorlin et al, 1990). The etiology of hemifacial microsomia is unknown, with both environmental and genetic factors proposed; 20% of the patients show marked facial asymmetry, but mild asymmetry is evident in 65% (Gorlin et al, 1990). Asymmetry results from hypoplasia or aplasia of the mandibular condyle and ramus. The maxillary, temporal, and malar bones may also be reduced in size. Anomalies of the heart, kidney, lung, and eye, have been reported. These patients have unilateral microtia, and preauricular tags of skin and cartilage are common, and supernumerary ear tags may occur anywhere from the tragus to the angle of the mouth (Gorlin et al, 1990). The prevalence of hypodontia in hemifacial microsomia patients has been reported to be 25 to 27% (Farias et al, 1988, Maruko et al, 2001) and absence of one tooth is most common. There is an increase in prevalence of missing teeth with increasing severity of the mandibular deformity. The tooth most commonly missing is the mandibular second premolar, followed by the maxillary second molar, mandibular second molar, mandibular lateral incisor, maxillary second premolar, and maxillary lateral incisor in the study of (Maruko et al, 2001).
Text adapted from Sirpa Arte: Phenotypic and genotypic features of familial hypodontia. Dissertation, Institute of Dentistry, University of Helsinki, Finland, 2001.
Text last edited 09.10.2003 by P.N. , page last created 10.12.2004 by P.N.