The morphology of the mucoperiosteal vascular plexus changed with bone metabolism and these changes contributed to transport of substances involved in periodontal repair.

When the mucoperiosteal flap was elevated, active wound healing was activated because of angiogenesis from the PDL, which possesses a microcirculatory system. Moreover, it was suggested that angiogenesis of the PDL vascular plexus and subsequent bone resorption of alveolar bone might temporarily reduce the tooth-supporting function and cause postoperative mobility.

Nobuto has previously reported on the initial anastomosis involved in establishing circulation between a free gingival autograft and the recipient bed. This study will present observations on the maturation of new sinusoidal vessels involved in maintaining circulation to the graft and the resulting histovascular organization. Using 56 mongrel dogs, the ongoing processes were observed periodically over 84 days after grafting. For this purpose, vascular corrosion casts were examined with the scanning electron microscope. At the same time, employing both light microscopy and transmission electron microscopy, histopathological and ultrastructural observation on the developing three-dimensional vascular architecture were recorded with supporting photographs. Thus, the entire process from the development of a vascular plexus parallel to the bone surface on the seventh day to the transformation to a vertical dendritic vascular architecture firmly establishing the circulation to the graft by the 84th day, is provided in both descriptive and pictorial detail.

Most periodontal surgery has been performed on the basis of the regenerating capacity of the periosteum. Recently it has been pointed out that the blood supply is important to the osteogenic and fibrogenic activity of the periosteum. The purpose of the present study was three-dimensional observation of blood vessels distributed within the gingival periosteum and the periosteum beneath the alveolar mucosa of adult mongrel dogs. Corrosion cast specimens of vessels were observed from three directions: mucosal side, bone side, and horizontal cut surface. It was revealed that the plexus distributed in the periosteum of the gingiva formed a coarse network structure, which consisted mainly of arterioles and venules. In contrast, in the periosteum of the alveolar mucosa, a dense network structure consisting of arterioles, capillaries, and venules formed a vascular bed. Thus, the mucogingival junction was easily located even in the plexus of periosteum which was distributed beneath the gingiva and the alveolar mucosa, suggesting that the difference in tissue specificity was reflected in the plexus of the periosteum.

After mucoperiosteal flap elevation, the periosteal vasculature exhibited potent blood vessel-forming activity through various angiogenic mechanisms and through repair activity. Our results provide a 3-dimensional clarification that the periosteal vascular plexus has an important role in the healing process after flap surgery.