Emergence of permanent teeth in Tanzanian children.

Objective: The aim of the present study was to investigate the emergence of permanent teeth among Tanzanian children.

Methods: A total of 869 Tanzanian children were recruited from 16 schools in age groups 3.5-5, 6.5-8, 9.5-11 and 15-16 years of whom 428 (49%) were boys and 441 (51%) were girls. The effects of age and gender on the emergence stages of the dentition were determined for the four age groups.

Results: Girls, but not boys, had some permanent maxillary canines, second premolars and mandibular and maxillary second molars as early as at the age of 6.5-8 years. Permanent teeth of both the first and the second transitional periods were already emerging at the age of 3.5-5 years and 6.5-8 years, respectively. At 3.5-5 years, 9% of the permanent teeth belonging to the first transitional period were already in occlusion. Emergence of incisors and first molars was more advanced in girls than in boys in age groups 3.5-5 and 6.5-8 years.

Conclusions: Parallel to earlier reports on different ethnic groups, the results of this study indicate that the permanent teeth of Tanzanian children erupt earlier in girls than in boys, and the mandibular teeth erupt earlier than the corresponding maxillary teeth. The difference between boys and girls was found in both the first and second transitional period. Permanent teeth in Tanzanian children clearly emerge earlier than in Caucasian children.