Study of the number of roots and canals in Senegalese first permanent mandibular molars.

A study of 480 extracted first permanent mandibular molars of the Oulof people of Senegal, West Africa, revealed 15 teeth with three roots (3.12%), and 120 teeth with four root canals (25%). An extra root correlated with a sextum lingual tubercle in 20% of cases. Analysis of the pulp chambers revealed a variety of rectangular shapes. Comparison of these anomalies with their incidence in other ethnic groups extends the range of incidence of three-rooted first permanent mandibular molars in the Negroid race. This trait is described for only the second time in a Negroid population. The clinical consequences of root variation in root canal treatment are considered.