Contribution of the periosteum to bone formation in guided bone regeneration - A study in monkeys

The periosteum has been referred to as a protective barrier in the regenera tion of bone defects, The objective of this study was to determine the cont ribution of periosteum as a natural barrier to bone formation in guided bon e regeneration. Mucoperiosteal flaps were elevated bilaterally on the bucca l aspect of the mandibular angle in 5 cynomolgus monkeys. Bleeding was indu ced by perforating the cortical bone. A hemispherical titanium mesh was fix ed over the areas thus creating a void 5 mm in height between the mesh and the bone surface. On one side the mesh was covered with an ePTFE membrane ( test side). The contralateral side did not receive further treatment (contr ol side). After 4 month healing, histomorphometric analyses were used to de termine the percentage of new bone in the void underneath the mesh, and the ratio between mineralized tissue and marrow spaces in new and old bone. Th e mean percentage of new bone tissue was 77.2+/-7.5% for the test sides and 68.6+/-8.4% for the control sides (P=0.018, t-test). This new bone contain ed 80.0+/-3.6% mineralized tissue in the test group and 82.5+/-5.0% in the control group (P>0.05, t-test). In both groups the newly formed bone exhibi ted significantly less mineralized tissue than the old bone (P<0.05, t-test ). It is concluded from this study that new bone formation was enhanced by the additional use of an ePTFE membrane under a periosteum-lined mucoperios teal flap when space maintenance was excluded as a critical factor.