Method: β-tricalcium phosphate grafts (Vitoss®) with the following dimensions 6mm width x 3mm height x10mm length- were placed directly onto decorticated cortical bone on the lateral aspect of the left maxillary diastema of New Zealand white rabbits (n=6). The graft was secured to the underlying bone using an 8mm titanium screw, covered with a resorbable collagen membrane and the surgical site closed over. Tissue blocks were harvested at 3 weeks and 6 weeks.
Two non-decalcified sections were scanned using a micro tomographic imaging unit. Four sections were embedded in resin, stained with Pyronin-G and evaluated histologically. Graft vascularisation was examined on one decalcified frozen section labelled with anti-CD31 monoclonal antibody.
Result: All six sites healed well with one site showing some minor wound dehiscence. The micro-CT analysis demonstrated that the central screw appeared to help retain the graft material in place with the graft height around the titanium screw being maintained. The periphery of the graft however showed some loss of height.
Histological evaluation demonstrated cellular invasion of the graft with osteoblasts and connective tissue infiltration noted. The anit-CD31 labelling demonstrated vascular infiltration of the grafted region.
Conclusion: The study concluded that the model was appropriate for testing the use of a synthetic bone graft material for augmentation of a reduced alveolar ridge. The histological examination demonstrated evidence of colonisation of the graft by bone forming cells. A longer observation time period with a greater number of test sites using a centrally placed titanium implant in place of the screw is recommended for further evaluation of bone tissue regeneration.