TOOTH ROTATION ASSOCIATED WITH APLASIA OF NONADJACENT TEETH

The prevalence of tooth rotation concomitant with aplasia of nonadjace nt teeth in uncrowded, nonsyndromic subjects was assessed. The sample consisted of 1620 subjects (mean age 14 years 9 months). The findings were compared with the prevalence calculated for a matched control gro up of 1000 subjects. Rotation of maxillary lateral incisors in subject s with premolar aplasia and rotation of premolars in subjects presenti ng with maxillary lateral incisor aplasia were studied. Associations b etween both tooth position anomalies and tooth aplasia were significan t (p < 0.01). in addition, the presence of rotated maxillary lateral i ncisors was also associated with aplasia of the homologous tooth on th e opposite side of the dental arch; the same result was found for prem olars. These data suggest a genetic component in the etiology of tooth malpositions, such as tooth rotation, which may be considered a covar iable in a complex of genetically controlled dental disturbances, incl uding tooth aplasia.