The Biomechanics Characters And The Morphological Changes Of The Mandible Cancellous Bone When Being Compressed

Objectives: 1. one objective of this study is to investigate the biomechanics performance of the mandible cancellous bone when it was compressed under a certain velocity. Comparing the differences of the biomechanics performance among the anterior teeth area, the premolar teeth area, and the molar teeth area. 2. Observing the morphologic parameter of the cancellous bone after compressed for a certain distance, investigating the changes before and after compression. It provides fundamental knowledge for the advanced experiments.Material and the methods: 1. In the first part of the study, five jaws was divide into three groups: the anterior teeth area, the premolar teeth area, and the molar teeth area.. The compact bone of the 5 mandibles should be wiped off, then divided cancellous bone into test pieces. Compress the test pieces at a rate of 1mm/min, and the laboratorial machine gave out the results. Then status analysis should be applied to the experiment data. 2. Compressed the test piece with the biting direction to the extent of 0.3mm。Prepare the non-decalcification sections of the cancellous bone. Use the semi-automatic—LEICA to observe the sections and the software Osteomeasure to do the statistics analysis.Results: 1. Use statistics analysis method to analyze the three groups' Young's modulus and maximal load value. The results shows that the anterior teeth area group's Young's modulus is smaller than the premolar teeth area group's, and the molar teeth area is the maximal. The discrepancy has statistical significance. The results shows that the anterior teeth area group's maximal load value is smaller than the premolar teeth area group's, and the molar teeth area is the maximal. The discrepancy has statistical significance. 2. After being compressed for 0.3mm, the bone tissue morphologic parameters, like the Tb.N,T.Ar,Tb.Ar, augment. And the Tb.Th,Tb.Pm, show no changes. The distance between the trabecular bones, grows down.Conclusion: l.The of the premolar teeth area and can hold more pressure than the anterior teeth area, the molar teeth area has the maximal EM and UL. The biomechanic behavior of the between left and right of the same area is similar.2.After the cancellous bone was compressed for a certain distance, the changes of the morphological parameters show a phenomenon of elevation of bone density.The observation of the sectiones tells no significant bone morphous change.