Effect of splinting on the mechanical and histological properties of the healing periodontal ligament in the vervet monkey (Cercopithecus aethiops)

Healing of the periodontal ligament (PDL) after extrusive luxation of two upper central incisors was evaluated when one tooth was splinted and the other left untreated. One millimetre thick, transverse sections of tooth, PDL and alveolar bone were examined in a materials testing machine. Load deformation curves were recorded and a number of mechanical properties were assessed. To eliminate the influence of differences in sizes and fibre arrangements, load values were reduced by the area and deformation values by the width of the PDL, and comparisons between splinted and non-splinted teeth were made at identical root levels 2 weeks after injury. Healing was also evaluated histologically at 1, 2, 3, 4 and 8 weeks after injury. There were no significant differences in mechanical and histological properties between splinted and non-splinted teeth, which suggests that splinting is of doubtful value in treatment of extrusive luxated teeth. The values for the mechanical properties of injured PDL had returned to 50-60% of those of uninjured PDL by 2 weeks after injury, indicating a rapid healing rate.