BACKGROUND

To compare the histologic difference in healing between ridge preservation sites treated with a combination allograft of 70% mineralized and 30% demineralized freeze-dried bone allograft (FDBA) evaluated at 8 to 10 weeks versus 18 to 20 weeks post-extraction. Changes in morphological ridge dimensions were also evaluated.

METHODS

Forty-four patients with a single-rooted tooth to be extracted and replaced by a dental implant were recruited for this study. At time of extraction, measurements were taken with a custom acrylic stent, and the extraction socket was grafted with the combination allograft and covered with a nonresorbable membrane. Patients were randomly assigned to the short-term (8 to 10 weeks) or long-term (18 to 20 weeks) healing group. Sites were re-entered for study measurements, a bone core sample, and implant placement. Bone cores obtained during implant placement were analyzed histologically to determine percentages of vital bone, residual graft, and CT/other.

RESULTS

Thirty-eight of the 44 patients completed the study, 19 in each group. There was a significant difference between the two groups for mean percent vital bone formation (short-term = 18.17%, long-term = 40.32%, P = < 0.0001) and percentage of residual graft (short-term = 41.54%, long-term = 23.59%, P = < 0.0001). There was no difference in morphological changes between the two groups.

CONCLUSION

Ridge preservation using combination FDBA resulted in approximately twice as much vital bone and half as much residual graft material after 18 to 20 weeks of healing compared to only 8 to 10 weeks healing.