FREQUENCY, SIZE, AND BILATERALISM OF CARABELLI'S TUBERCLE

¹ College of Dentistry, State University of Iowa, Iowa City, Iowa

A study was made of the occurrence, size, and bilateralism of Carabelli's tubercle in 100 physically normal, 9-year-old Iowa children of northwest European ancestry. The basic data were controlled observations on dental casts, that is, observations of the lingual surfaces of the mesiolingual cusps of the permanent maxillary first molars.

Eighty-four per cent of the 200 first molars examined were found to show some amount of supplemental protuberance. Approximately 60 per cent had moderate to large prominences, while 16 per cent lacked any observable accessory elevation. The largest tubercle in the series measured 5.5 mm. in maximal mesiodistal diameter, projected 3.0 mm. lingually from the surface of the mesiolingual cusp, and lacked approximately 1.5 mm. of extending occlusally to the level of the mesiolingual cusp.

Thirteen per cent of the children exhibited no accessory elevation on one side of the arch and a slight to moderate elevation on the other. There was an observable difference in the size of the tubercle on the right and left sides for 70 per cent of the subjects.