Ridge Preservation With and Without Primary Wound Closure: A Case Series

The purpose of this study was to determine the clinical and histologic efficacy of the combination of alloplastic biphasic calcium phosphate composed of 30% hydroxyapatite and 70% beta-tricalcium phosphate (Osteon II) and a cross-linked collagen membrane used to reconstruct an extraction socket with new bone formation. Twelve patients, from two private dental practices, requiring extraction of maxillary and mandibular nonmolar teeth (n = 30) received both Osteon II (0.5- to 1.0-mm particle size) and the collagen membrane. The primary healing intention group (group A, n = 12) received primary flap closure over the membrane, while in the secondary healing intention group (group B, n = 18), the membrane was left exposed. Early wound healing seemed to be slower in group B when compared to group A, but the difference was not noticeable after 4 weeks. Clinical reentry revealed that the dimensions of the ridge appeared to be maintained in both groups, and internal socket bone fill was evident. The grafted area appeared to be well vascularized, but clinically visible graft particles were noted in some cases. Light microscopic analysis revealed the formation of new bone directly apposing the surfaces of graft particles and bridging the space between them, indicating that the graft material behaved as an osteoconductive scaffold. The mean amount of vital bone in group A was 40.3% +/- 7.8%, while the remaining graft was 6.0% +/- 4.0%. The mean amount of vital bone in group B was 47.3% +/- 11.3%, while the remaining graft was 18.0% +/- 20.0%. The absence of primary flap closure did not affect the percentage of vital bone formation or residual graft.