Histologic Comparison of Healing Following Tooth Extraction With Ridge Preservation Using Two Different Xenograft Protocols

Abstract

The objectives of this study are to compare differences in histologic and clinical healing following tooth extraction and ridge preservation using two different xenograft treatment protocols. Forty-four patients with a non-molar tooth that required extraction and planned implant placement were randomly allocated into two ridge preservation protocol groups. Protocol 1 used a xenograft material consisting of 90% anorganic bovine bone in combination with 10% porcine collagen fibers combined with a resorbable bilayer membrane composed of non-cross-linked porcine types I and III collagen. Protocol 2 used a xenograft sponge composed of 70% cross-linked type I bovine collagen coated with a layer of non-sintered hydroxyapatite mineral on its surface combined with a resorbable membrane composed of type I porcine collagen cross-linked by natural ribose glycation. Following 21 weeks of healing, clinical measurements were repeated, and a core biopsy was obtained and prepared for histologic evaluation of percentages of vital bone, residual graft, and connective tissue/other (CT/other). Similar percentages of CT/other were detected between protocols, with no significant difference between groups (P = 0.763). A significantly greater percentage of vital bone was detected in specimens in protocol 2 (P <0.001). Protocol 1 presented with a mean of 32.83% ± 14.72% vital bone, 13.44% ± 11.57% residual graft material, and 53.73% ± 6.76% CT/other. Protocol 2 presented with a mean of 47.03% ± 9.09% vital bone, no detectable residual graft material, and 52.97% ± 9.09% CT/other. Clinically, no significant differences in dimensional changes were evident between ridge preservation protocols. To the best of our knowledge, this study represents the first randomized controlled trial to evaluate clinical and histologic differences seen when using these two xenograft protocols for ridge preservation.