OBJECTIVEThe morphological characteristics of posterior tooth in the Beagle dog were investigated in order to provide reference to mini-screw implant (MSI) implantation in the root furcation site.

METHODSSeventy posterior teeth of five Beagle dogs were collected and measured as follows: First, the greatest mesio-distal diameter AB of the crown was measured, which was perpendicular to the tooth long axis. Second, mesial cusp of maxillary posterior tooth or central cusp of mandibular was marked as the piont C, and CD which was equal and perpendicular to AB was drawn. The piont D was planned to be the reference point for MSI implantation. Finally, Dm, Dd and Df were measured, which were the distance from the point D to the mesial and distal root surface and root furcation.

RESULTSThe difference between the left and right sides teeth with the same name had no statistical significant (P > 0.05). The measurement results of all indices assumed a Gaussian distribution. The mean Dd was basically equal to Dm. All the average Df were more than 4 mm.

CONCLUSIONThe point D could be used as a reference point for MSI implantation in the root furcation site of posterior tooth in the Beagle dog. The data of this study can provide certain reference for MSI implantation in the study of the biomechanics of anchorage stability, and provide certain reference for MSI implantation in the study of root repair after injury.