Effect of Healing Time on New Bone Formation After Tooth Extraction and Ridge Preservation With Demineralized Freeze-Dried Bone Allograft: A Randomized Controlled Clinical Trial

Background: Clinicians and patients continually search for procedures to decrease time from tooth extraction to restoration. Evidence to date is limited concerning timing of ridge preservation healing and reentry for implant placement. The first objective of this study is to histologically evaluate new bone formation 8 to 10 weeks versus 18 to 20 weeks after extraction of non-molar teeth and ridge preservation using demineralized freeze-dried bone allograft (DFDBA). The second objective is to compare dimensional changes including ridge width and height at the two healing time points. Methods: Forty-four patients had tooth extraction and ridge preservation with DFDBA that was obtained from a single donor. Clinical measurements were made to evaluate ridge height and width. Patients were randomly allocated to short-term (8 to 10 weeks) and long-term (18 to 20 weeks) healing groups. Sites were reentered at the appropriate healing time, core biopsy was obtained, and a dental implant was placed. The same ridge dimensions were measured at time of implant placement. Histomorphometric analysis was performed to determine percentage of new vital bone formation, residual graft, and connective tissue (CT)/other. Results: A significantly higher percentage (47.41%) of new vital bone formation was found in the long-term healing group compared with the short-term healing group (32.63%) (P = 0.01). There was no significant difference in percentage of residual graft, percentage of CT/other, or ridge dimensional changes. Conclusion: This study indicates significantly greater new vital bone formation occurs after tooth extraction and ridge preservation with DFDBA when sites healed for 18 to 20 weeks compared with 8 to 10 weeks prior to dental implant placement.