ANALYSIS OF POLYMERIZATION CONTRACTION IN COMPOSITES

越来越多的临床和实验室证据表明，关节的弯曲 冠内复合收缩后的牙冠可能是 与一些临床和生物现象有关，包括早期 牙本质粘结失效，裂纹的萌生和扩展，并可能 手术后症状。这项提议的一个主要目标是 这些病变的范围和可能的临床意义的测定 在体外实验模型中伺服液压控制和 直接从完整和修复的人类牙齿中读出。这个 待检验的假设是复合材料的聚合收缩 修复体材料会降低修复体的寿命 由于内应力的发展，早期牙本质粘结失效， 牙合接触的改变与牙合裂纹的萌生和扩展 天然的牙齿结构。复合材料的生物力学研究 聚合动力学及其对牙齿结构的影响将是 研究内容：1)聚合反应的应变片表征 收缩应变和应力，2)变形的评估 应变片测量复合体修复牙3)评价 复合体修复牙在模拟咬合过程中的反应 人工口腔中的载荷及验证有限元分析 修复后的牙齿复合体。希望这些研究能够 在内部增加生物力学相互作用的知识库， 在重要的边界和修复的牙齿表面 很复杂。由此，材料开发中的新标准可以 为材料的选择、治疗计划、 并且可以开发冠内修复体的制造。

There is mounting clinical and laboratory evidence that the flexure of the dental crown following intracoronal composite shrinkage may be related to a number of clinical and biological phenomena, including early dentin bond failure, crack initiation and propagation, and possibly post-operative symptoms. A major goal of this proposal is the determination of the extent and possible clinical significance of these effects in an in vitro experimental model with servohydraulic control and direct strain read out from intact and restored human teeth. The hypothesis to be tested is that polymerization contraction of composite restorative materials results in decreased longevity of the restoration due to internal stress development, early dentin bond failure, alterations in occlusal contacts, and crack initiation and propagation of the natural tooth structure. The biomechanics of composite polymerization kinetics and its effects on tooth structure will be investigated by: 1) strain gage characterization of polymerization contraction strain and stress, 2) evaluation of the deformation of the composite restored tooth through strain gage measurement, 3) evaluation of the response of the composite restored tooth during simulated occlusal loading in an artificial mouth and 4) validated finite element analysis of the restored tooth complex. It is hoped that these studies will increase the knowledge base of the biomechanical interactions internally, at significant boundaries and on the surface of the restored tooth complex. From this, new criteria in materials development can be determined and a sounder basis for materials choice, treatment planning, and fabrication of intracoronal restorations can be developed.