An experimental model to study the biomechanical properties of maxillary bone tissue

The study of biomechanical properties of maxillary bone tissue is essential to assess its response to different pathologies and therapies. Post-tooth extraction bone repair in rats is an experimental model of active osseogenesis and bone remodeling. Reports, both clinical and experimental, on the biomechanical properties of the maxillae are scant. A standardized method to obtain and analyze samples has not been described to date and there are no reports evaluating the biomechanical features of cancellous bone of the edentulous alveolar ridge. The aim of this study was to develop a standardized method to obtain samples to evaluate the mechanical properties of mandibular cancellous bone of the edentulous alveolar ridge, formed di novo during the post-tooth extraction bone repair process in rats. Following a previously described technique (Guglielmotti et. al. J. Oral Maxillofac. Surg. 43:359,1985) the lower molars of 4 Wistar rats were extracted. The animals were euthanized 30 days post-extraction in keeping with the NIH guidelines (NIH Publication No 85-23, Rev. 1985) and those established by the Ethics Committee of the School of Dentistry of the University of Buenos Aires. The maxillae were resected, radiographed, dehydrated in graded solutions of alcohol of increasing concentration, and embedded in epoxy resin. The particular anatomical features of these experimental animals were taken into account to obtain the samples. Mandibular rat incisors undergo continuous eruption and are located in the lower portion of the mandibular body, below the molar roots, offering a cleavage plane to separate the edentulous alveolar ridge from the mandibular body. Ground sections parallel to the upper surface of the alveolar ridge were obtained manually using sandpaper (600, 1000 y 1200) and polished using alumina solution. The present model allows evaluating the biomechanical properties of this mandibular cancellous bone by means of nanoindentation of the newly formed cancellous bone tissue, and establishing correlations with histomorphometric and histologic studies.
Grants: UBA O 020 and CONICET PIP 6042