Caudal Mandibular Bone Height and Buccal Cortical Bone Thickness Measured by Computed Tomography in Healthy Dogs

To characterize bone height and buccal cortical bone thickness of the caudal mandible of healthy dogs.

Prospective original study.

Client-owned dogs (n = 36).

Dogs were distributed by weight into 3 groups (<10, 10-20, >20 kg). Thirteen transverse plane computed tomography images were selected for each dog based on anatomic landmarks from the 4th premolar (PM4) through the 2nd molar. On each image, bone thickness was measured along the buccal surface of both mandibles from the alveolar margin to the ventral border in 3 mm increments. The number of 3 mm increments were recorded as an estimation of mandibular height.

Buccal bone was generally thicker ventrally in the area studied with decreasing bone thickness over both roots of PM4 and the mesial root of the 1st molar (M1). Cortical bone thickness of <2.0 mm was measured across all groups at most locations 3 mm ventral from the alveolar margin. Mandibular bone height demonstrated significantly fewer (P < .05) 3 mm increments over the distal root of M1 in dogs >10 kg compared with the number of observations at the immediately mesial and distal locations.

Thin cortical bone overlying the mesial and distal roots of PM4 and the mesial root of M1 limits use of these areas for application of monocortical anchorage devices. Decreased mandibular bone height at mandibular M1 may create a stress riser at this location, which along with thin cortical bone may explain why this is a common area for mandibular fracture.