Demineralization of the Contacting Surfaces in Autologous Onlay Bone Grafts Improves Bone Formation and Bone Consolidation

Background: Autologous bone grafts are usually well consolidated after 4 to 5 months but can be incompletely interlocked with the native bone. This study investigated the effect of acid demineralization of the graft-bed interface on graft consolidation.

Methods: Onlay bone grafts were performed on the calvaria of 36 guinea pigs. Half of the animals had the graft-bed contacting surfaces demineralized with 50% citric acid (pH 1.0) for 3 minutes (test group). The other half received no demineralization (control group). The bone grafts were immobilized by a resorbable membrane glued to the recipient bed with cyanoacrylate. After 7, 30, and 90 days, specimens (n = 6) were obtained for light microscopy. Data from qualitative analysis and computerized histomorphometry were statistically processed at a significance level of 5%.

Results: Osteogenesis was not seen at the interface after 7 days. After 30 days, the test group showed 34.39% ± 13.4% of the interface area filled with mineralized tissue, compared to 17.14% ± 8.6% in the control group (P = 0.026). After 90 days, the mean percentages of mineralized tissue at the interface in the test and control specimens were 54.00% ± 11.23% and 38.65% ± 7.76% (P = 0.041), respectively. Within groups, a higher percentage of the area filled with mineralized tissue was seen at 90 days compared to 30 days (P = 0.004 for control and 0.041 for test).

Conclusions: Demineralization of the contacting surfaces between autologous bone graft and bone bed improved new bone formation and bone consolidation. These data need to be confirmed in humans.