Occlusal forces promote periodontal healing of transplanted teeth with enhanced nitric oxide synthesis

It has been reported that occlusal forces promote periodontal healing of transplanted teeth and prevent dentoalveolar ankylosis, although its mechanism is still unclear. Nitric oxide (NO) produced by NO synthase (NOS) is considered to be an important factor which is involved in wound healing, and it increases with mechanical stimuli. The objective of this study was to examine the relationship among occlusal stimuli, inducible NOS (iNOS) and PDL healing of transplanted teeth. Five-week-old Sprague-Dawley male rats were used for this study. The right maxillary first molars of rats were replanted and animals were divided into occluded and non-occluded groups. Histologic observations were carried out after one and two weeks. After two weeks, the non-occluded group had clearly detectable ankylosis and obvious PDL stricture. On the other hand, the occluded group showed an enlarged and thickened PDL without ankylosis. The number of iNOS positive cells in the occluded group, samples significantly increased in comparison to that of the non-occluded group. These results suggest that occlusal stimuli enhanced the production of NO in the PDL healing process of transplanted teeth and a favorable result could be obtained.