Wound healing after ridge preservation: A randomized controlled trial on short-term (4 months) versus long-term (12 months) histologic outcomes.

BACKGROUND: The amount of time it takes for bone allograft particles to be replaced with new vital bone during ridge preservation is unclear. The purpose of this article was to compare the wound healing and vital bone formation following ridge preservation using a combination allograft of 70% mineralized and 30% demineralized freeze-dried bone allograft at 4 months (short-term, ST) versus 12 months (long-term, LT). METHODS: Fifty-seven patients were enrolled in the study who required extraction of a single tooth (excluding second and third molars) and were planned for replacement with a dental implant. After tooth extraction, all sites were grafted with a combination allograft procured from a single donor, and patients were randomized into the ST or LT healing groups. Patients returned for implant placement and an 8-mm bone core biopsy was harvested using a trephine drill during initial implant osteotomy preparation. The cores were then analyzed histologically to determine the percentages of vital bone formation, residual graft particles, and connective tissue/other. RESULTS: There was significantly greater vital bone formation in the LT group (51.38%) compared with the ST group (31.39%) (p = 0.0025) and significantly fewer residual graft particles in the LT group (18.04%) compared with the ST group (40.38%). CONCLUSIONS: A longer healing time following ridge preservation results in more vital bone formation and less residual graft particles at the time of implant placement. However, residual allograft material still remains at 12 months after ridge preservation.

Long-term preservation of ridge dimension following tooth extraction and ridge preservation: A randomized controlled trial of healing at 4- and 12-month healing time points.

BACKGROUND: To date, the efficacy of ridge preservation in the maintenance of the residual alveolar ridge dimension beyond 6 months after treatment is unknown. The purpose of this study was to compare the differences in alveolar ridge dimensional change following ridge preservation between 4- and 12-month healing time points using cone-beam computed tomography (CBCT). METHODS: Fifty seven patients planned for tooth extraction and implant placement were enrolled. Following extraction, ridge preservation was performed. CBCT scans were taken within 72 hours following extraction with a customized resin stent containing a fixed radiographic marker. At either 4 months (short-term, ST group) or 12 months (long-term, LT group) after ridge preservation, patients had a second CBCT taken and an implant placed. Changes in ridge height and width were measured using the standardized radiographic marker. RESULTS: No significant differences were detected between the ST and LT groups in loss of buccal and lingual ridge height. Similarly, when adjusted for baseline ridge width, no significant differences were detected in ridge width loss at 3, 5, and 7 mm apical to the crest between the ST and LT groups. CONCLUSIONS: The efficacy of ridge preservation in the maintenance of ridge width and height at the 12-month time point is similar to that of the 4-month time point. Clinicians may feel confident that a delay in implant placement for up to a year has no significant negative impact on the height and width of the healed ridge.