THE EFFECT OF MECHANICAL INTERVENTION ON JAW BONE-DENSITY - AN EXPERIMENTAL-STUDY IN THE RABBIT

The aim of this investigation was to test the hypothesis that jaw bone , subjected to mechanical intervention, will heal with increased densi ty compared with conditions before the traumatic insult, The natural e dentulous area between the incisor and the first molar on both sides o f the maxillary jaw of 8 adult New Zealand white rabbits constituted t he experimental model. On the test side, holes were drilled through th e cortical plate and into the cancellous bone. No drilling was perform ed on the contralateral control side. One transversal ground section f rom each specimen, taken in the centre of and representing both the te st and control site, was prepared to ensure that the same sagittal lev el of the jaw was represented. Morphometric measurements were performe d and comprised assessments of the total cross-sectional area of 1) th e edentulous part of the jaw, 2) the cortical bone plates and 3) the b one trabeculae and marrow spaces of the cancellous bone. The mechanica l intervention resulted in a substantial alteration of the bone tissue morphology, the most conspicuous change being a markedly increased nu mber of bone trabeculae per cancellous bone unit. Thus, the area occup ied by bone trabeculae was about twice as large in the test sites comp ared with the control sites (+103%), whereas the area occupied by bone marrow cavities and cortical bone was significantly smaller. The clin ical implications of the findings for potential treatment of fragile b one tissues and bone sites intended for implant insertion are discusse d.