A morphologic study of the mesial root surface of the adolescent maxillary first bicuspid.

Treating periodontitis which involves the mesial concavity of the maxillary first bicuspid can be very challenging. Fifty extracted adolescent maxillary first bicuspids were sectioned in 2-mm thick sections apical to the cementoenamel junction (CEJ). The mesial concavity depth and the cementum and dentin thickness were measured in the sections. The single-rooted bicuspids have a concavity 0.35 mm deep at the CEJ and a concavity 0.59 mm deep 4.7 mm apical to the CEJ. Two-rooted bicuspids furcate at 7.9 mm and have a concavity 0.44 mm deep at the CEJ which increases to 1.08 mm at the 4.7 mm level. Cementum thickness averages from 0.9 mm at the CEJ to 1.1 mm at the 9.4-mm level. Most bicuspids also have a distal concavity which is deepest at the 4.7-mm level. The results imply that any attachment loss around the maxillary first bicuspid involves surfaces which are most likely concave. These concave surfaces make both plaque removal and various periodontal therapeutic procedures difficult.