Methods: The study group comprised 45 males and 21 females, ranging in age from 7 to 39 years, 66 patients in all. The patients were assessed for eight heritable dental anomalies namely, hyperdontia, hypodontia, microdontia, infraocclusion of primary molars, ectopic canines, ectopic premolars, ectopic first permanent molars and ectopic second permanent molars. The patients were matched with respect to age and gender to 66 consecutively selected control subjects with similar selection criteria but no history of problems with incisor eruption. The prevalence rates of the dental anomalies in association with failure of eruption of incisors were compared to the control group by means of Pearson chi-squared tests.
Results: The results of this study demonstrate a statistically significant association between unerupted incisors and other heritable dental anomalies, namely ectopic teeth, ectopic canines, hyperdontia, hypodontia and microdontia. Furthermore the prevalence of unerupted incisors is higher in males than females irrespective of the presence of a supernumerary tooth.
Conclusions: Unerupted incisors and supernumerary teeth may be considered part of a spectrum of heritable dental anomalies. Failure of eruption of an incisor shows a male bias, independent of the presence of a supernumerary tooth.