Oral and maxillofacial surgeryInfluence of unilateral tooth loss in the temporomandibular joint and masseter muscle of rabbits

ObjectiveThe purpose of this study was to evaluate the influence of the masticatory system in patients with missing teeth.Study DesignThe influence of tooth loss on the masticatory system was analyzed with the use of bone scintigraphy (99mTc-MDP) and histochemistry. Eight white rabbits (New Zealand, 12 weeks old) were used. The rabbits were divided into 2 groups: 6 weeks and 12 weeks. Teeth were extracted unilaterally in each rabbit under general anesthesia. Six and 12 weeks after extraction, scintigraphy was conducted, and the rabbits were killed and their masseter muscles removed for histochemical analysis.ResultsThe results of bone metabolism (relative ratio) measured by bone scintigraphy were 48.27% at extraction sites and 51.73% at nonextraction sites at 6 weeks and 39.96% at extraction sites and 60.04% at nonextraction sites at 12 weeks. There was a significant difference at 12 weeks (P < .05). Tissue calcium contents and osteoclast counts showed different results between the extraction and nonextraction sites, but these differences did not reach statistical significance.ConclusionsThe bone metabolism of temporomandibular joints and histochemical aspects of masticatory muscles may be associated with occlusal alterations following tooth loss.