Prevention of the surface resorption of bone grafts by topical application of bisphosphonate on different carrier materials

Material and methods: In eight adult pigs, bone blocks were harvested bilaterally from the mandible and fixed to the lateral cortex of the horizontal ramus to simulate a ridge augmentation. In a split-mouth study design, we used alendronate in aqueous solution (1 mg/ml) on the test-side in three different ways: on a collagen membrane (Bio-Gide®), soaked in bovine bone mineral granules (Bio-Oss®), or applied to the bone graft directly. The same materials without BP were used as controls on the contralateral side. After 3 months, the animals were sacrificed. The evaluation included sequential fluorochromic labeling and measurement of bone height in microradiography and toluidine blue staining.

Objective: The hypothesis of the present study was that topically applied bisphosphonate (BP) on a collagen membrane or alternatively bovine bone mineral prevents surface resorption of onlay bone grafts.

Results: In five cases, necrosis of the overlying periosteal tissues with BP was observed macroscopically. A statistically significantly lower loss in graft height was seen on the test-side for Bio-Gide® + alendronate (0.65 %) versus Bio-Gide® (1.52 %), p = 0.002; Bio-Oss® + alendronate (1.16 %) versus Bio-Oss® (4.20 %), p = 0.001; and bone graft + alendronate (1.25 %) versus bone graft alone (6.01 %), p = 0.006. An inhibitory effect on bone remodeling was observed by a statistically significantly lower number of resorption lacunae.

Conclusion: The hypothesis was accepted that a bisphosphonate-treated membrane reduced bone graft resorption; however, periosteal necrosis requires better adaptation of the dosage.

Clinical relevance: A bisphosphonate membrane could be a helpful tool to preserve augmentation height of onlay bone grafts.