Objective: The purpose of the present study was to investigate the reaction of the periodontal ligament to alteration of occlusal loading by posterior raise bite with resin composite buildup.
Background: Despite extensive clinical use of unilateral posterior composite buildup to single tooth, the potential of periodontal ligament adaptation to the occlusal overload by the appliance remained to be clarified. An experimental model was used for investigating periodontal reaction to occlusal loading created by unilateral raise bite in vivo.
Methods: The occlusal surface of the maxillary left first molars of rats was elevated by resin composite in order to induce unilateral occlusal raise bite. The morphological change of the periodontal ligament was observed and the number of TRAP-positive cells in the area was also evaluated.
Results: Following the overload of occlusal force to the upper first molar by bite-raising, the periodontal width was significantly decreased from 12 h to 3d after treatment, but returned to normal level at day 7. At day 3, prominent compression of the periodontal ligament and osteoclast migration were observed at the apical interradicular septum.
Conclusions: Our model was useful for the detailed investigation of periodontal ligament adaptation during increased occlusal loading. Although a few TRAP-positive osteoclasts were transiently found at the interradicular septum, it seems that there was no obvious sign of periodontal destruction thereafter.