Abstract
In the mature mouse (C57BL/6SrSlc) two-month postnatal morphological changes in the incisive suture (InS) following the excision of the incisors in the upper and lower jaws at the level of their gingival margins were observed histologically. The incisors were excised repeatedly every three or four days because these teeth erupted continuously.
The InS of the mature mouse exhibited the complicated interdigitation of the well-developed bone trabeculae at the sutural surfaces of the premaxilla and the maxilla. The bone trabeculae of each bone were firmly connected to each other with collagen fibre bundles of regular orientation.
Seven days after excision, the collagen fibre bundles became thinner and their number decreased. Fourteen and twenty-one days after excision, osteoclasts appeared and the blood vessels proliferated and dilated in the suture. At this stage, the sutural surfaces altered and the unused collagen fibre bundles disappeared. Twenty-eight days after excision, the InS reformed. The collagen fibre bundles were thin in thickness and few in number compared with those in the InS of the mouse at sixty days postpartum.
The incisors regenerated and regained their masticatory function after we discontinued the excision experiments. The InS of these mice showed morphologically a recovery of it's connecting function with a remarkable formation of collagen fibre bundles.
The thickness and number of the collagen fibre bundles in the sutures of the mice which were fed a powder diet indicated an intermediate state between those of the InS of the mouse at sixty days postpartum and at twenty-eight days after the excision of the incisors.
These results indicate that the morphology of the InS is closely related to the intensity of the masticatory function of the incisors.
