The effect of mechanical intervention on jaw bone density

The aim of this investigation was to test the hypothesis that jaw bone, subjected to mechanical intervention, will heal with increased density compared with conditions before the traumatic insult. The natural edentulous area between the incisor and the first molar on both sides of the maxillary jaw of 8 adult New Zealand white rabbits constituted the experimental model. On the test side, holes were drilled through the cortical plate and into the cancellous bone. No drilling was performed on the contralateral control side. One transversal ground section from each specimen, taken in the centre of and representing both the test and control site, was prepared to ensure that the same sagittal level of the jaw was represented. Morphometric measurements were performed and comprised assessments of the total cross-sectional area of 1) the edentulous part of the jaw, 2) the cortical bone plates and 3) the bone trabeculae and marrow spaces of the cancellous bone. The mechanical intervention resulted in a substantial alteration of the bone tissue morphology, the most conspicuous change being a markedly increased number of bone trabeculae per cancellous bone unit. Thus, the area occupied by bone trabeculae was about twice as large in the test sites compared with the control sites (+103%), whereas the area occupied by bone marrow cavities and cortical bone was significantly smaller. The clinical implications of the findings for potential treatment of fragile bone tissues and bone sites intended for implant insertion are discussed.