Influence of experimental hemi-occlusion on mandibular morphology and internal structure in growing rabbit

Abstract

We induced experimental hemi-occlusion in growing rabbits to investigate the effect of masticatory laterality on the morphology and internal structure of the mandible. Three-dimensional morphometric data from micro-CT were used to compare changes in mandibular morphology and internal structure. Rabbits in the experimental group were placed under general anesthesia and their left maxillary and mandibular molars cut as far as the cervical area using a rabbit molar cutter. Thereafter, the teeth were cut once every 2 weeks. Rabbits were kept until they were 17 weeks old. For morphometric analysis of the mandible, we measured mandibular body length, mandibular length, mandibular ramus height and gonial angle. To analyze cancellous bone structure, we measured total volume, cancellous bone volume, cancellous bone volume density, trabecular thickness, trabecular number, trabecular separation, and trabecular spacing. Mandibular ramus height and gonial angle were significantly greater on the occlusal side in the experimental group than on the non-occlusal side. Cancellous bone volume density, trabecular thickness and trabecular number were significantly greater on the occlusal side in the experimental group than on the non-occlusal side, whereas trabecular separation and trabecular spacing were significantly lower on the occlusal side. The results indicate that differences in mechanical stimuli during the growth phase resulting from masticatory dysfunction or parafunction affect the morphology and internal structure of the mandible.