Localizing the osseous boundaries of micro-osteoperforations.
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INTRODUCTION: The aim of this work was to determine how far the effects of micro-osteoperforations (MOPs) extend within bone by quantifying the damage caused and the short-term bony adaptations that occur in and around the injury site. METHODS: With the use of a split-mouth design, 34 MOPs (Propel) were randomly placed in the mandibular furcal bone of 13 beagle dogs either 2 or 4 weeks before killing them. The control side received no treatment. Vickers hardness microindentation, microscopic computed tomography, and histologic analyses were performed to evaluate the bone surrounding the MOPs. RESULTS: Microfractures produced during insertion extended 0.6mm from the MOP sites. Cortical and trabecular bone were significantly less dense on the experimental than on the control side up to 4.2mm from the edge of the MOP, but side differences were small (<5%) beyond 1.5mm from the MOP. Experimental cortical bone was significantly softer than the control bone up to 0.8mm from the MOP after 2weeks of healing, and up to 0.5mm from the MOP after 4weeks of healing. Hematoxylin and eosin stained sections of cortical and trabecular bone showed small areas of woven bone within the MOP sites after 2weeks, and acellular areas of bone extending 0.5mm from the MOP. After 4weeks of healing, there were greater amounts of woven bone, as well as early signs of lamellar bone, in and around the MOP sites. Markedly increased TRAP activity extending up to 2.5mm from the MOP was evident after 2weeks, but not after 4weeks. Vital fluorescence staining showed diffuse bone deposition on the experimental side up to 1.5mm from the MOP margin. CONCLUSIONS: When MOPs are performed in beagle dogs, demineralization is transient and healing of the injured area, as well as remineralization of bone affected by MOP placement, begins during the first 2weeks. Although the transient effects extend farther, the principal effects extend only 1.5mm from the MOP site.