[Time of permanent teeth eruption in schoolchildren of Saint-Petersburg].

The terms of permanent teeth eruption were analyzed in 909 children (permanent residents of St. Petersburg) aged 7-15 years. The study showed that all groups of permanent teeth, except the first molars, erupted on the mandible earlier than on the maxilla. In girls only canines and second molars erupted earlier than in boys. There was virtually no sex-specific difference in the terms of eruption of both premolars, and the terms of the end of eruption of both groups of canines were virtually the same in boys and girls. Twenty-one children lacked some of permanent teeth by 15 years (the age considered as the upper threshold level for the end of normal tooth eruption). The most frequent teeth that failed to erupt in time were the upper lateral canines (33.3% of all teeth which failed to erupt by the age of 15 years), lower central canines and upper first premolars and molars (12.8% each).