The depth of the lingual fossa in permanent incisors of Norwegians. II. Differences between central and lateral incisors correlations, side asymmetry and variability.

The depth of the lingual fossa in permanent incisors of Norwegians (plaster casts and extracted teeth) was studied. In the plaster casts the depth of the lingual fossa in the right side incisors was (in mm): I,sup=0.51,I(2)sup= 0.30, I(1)inf =0.07 and I (2)inf =0.08. For 1(1)sup significant bilateral asymmetry was found (p<0.00l). All incisors were positively correlated in the depth of the lingual fossa, mandibular higher than maxillary. In both jaws centrals were better correlated across the midline than laterals, and centrals to laterals were less correlated than centrals to centrals and laterals to laterals. Interjaw correlations of 1(1)sup were higher than interjaw correlations with I(2)sup. Dental field theory is confirmed: The upper lateral and lower central were the most variable incisors in each jaw for lingual fossa depth. The values for this trait in Norwegians are within the Caucasoid range.