Healing at the interface between recipient sites and autologous block bone grafts affixed by either position or lag screw methods: a histomorphometric study in rabbits

ObjectiveTo compare the sequential healing at the interface gap occurring between autologous bone grafts and recipient sites using two types of fixation techniques. Material and methodsTwenty-four adult male New Zealand white rabbits were used. Two bone grafts were collected from the calvaria and secured to the lateral aspect of the angle of mandible in each animal. Cortical perforations at the recipient sites were performed. However, no modifications were applied to the graft for its adaptation to the recipient site. Two types of fixation techniques by position or lag screws were applied. This was done by preparing osteotomy holes smaller or larger than the screw diameter, respectively. The animals were sacrificed after 3, 7, 20, and 40days. ResultsAfter 3days, the distance between the graft and the recipient site was similar between the two different fixations. Due to the anatomical shapes of the recipient sites and grafts, the distance between the two parts was lower in the central region (<0.1mm) compared to the external regions of the graft (0.5-0.6mm). The first evidence of small amounts of new (woven) bone was seen after 7days, forming from the parent bone. The percentage increased after 20 and 40days. After 40days, the grafts were well incorporated within the recipient sites in both groups without any statistically significant difference. ConclusionsThe present study did not show superiority of one method over another. A fixation to a recipient site with perforations may be sufficient for incorporating an autologous bone graft even if its adaptation is not perfect and irrespectively of the fixation method. Distances of approximately half millimeter were bridged with newly formed bone.