三维形貌测量激光显微镜下对早期釉质龋的纳米结构分析

Three-dimensional and laser characterization of incipient in vitro carious lesions in human dental enamel

目的本研究通过三维形貌测量激光显微镜观察早期釉质龋的纳米结构变化,为龋病的预防及临床治疗提供理论依据。方法收集20颗因正畸拔除的新鲜前磨牙,随机分为2组,实验组(A组)与正常对照组(B组),A组暴露于人工脱矿液中4 d制备早期龋模型后,两组均制备纵断与横断面样品,在三维显微镜下进行光学、激光彩色及3D图像观察。结果光学图像可见A组表层完整,表层下白垩色,B组无此分层;激光彩色图像观察到A组表层釉柱晶体排列紧密,釉柱间质正常,釉柱鞘清晰连续,表层下晶体溶解,排列混乱,釉柱间质增宽,釉柱鞘不连续,B组结构正常;3D图像更清晰显示了A、B两组的微结构形貌。结论三维显微镜能够更清晰的显示早期釉质龋的表层及表层下的微晶结构,表层的相对完整性与再矿化有关,表层下以微晶体脱矿为主,是脱矿与再矿化连续动力学过程。

【Objective】To examine the nanostructure of incipient in vitro carious lesions in dental enamel using three-dimensional topography and laser microscope.【Methods】 Twenty fresh premolar teeth in orthodontic pulling were collected and randomly divided into experimental group（group A） and normal control group（group B）. In the group A incipient carious lesions were obtained on the buccal side by exposure to artificial demineralization liquid for 4 days. The teeth in the two groups were then cut in longitudinal section and cross section. The sections were then examined using the three-dimensional and laser morphology. 【Results】The group A showed little evidence of lesion growth on surface or demineralization under the surface in the optical imagery. But under laser microscope, the group A showed that surface enamel rod crystals were aligned closely, enamel rod sheath was clear and continuous; the crystals of subsurface dissolved disorderly,the interval of enamel rod broadened, enamel rod sheath was fuzzy and discrete. However, the group B did not have this performance in the laser color images. 3D images more clearly showed the microstructure characteristics of the two groups. 【Conclusions】 Three-dimensional topography laser stereo microscope can accurately show morphology and structure of surface and subsurface of incipient carious lesions. The integrity of the surface is related to remineralization, and the subsurface mainly undergoes demineralization of micro-crystals.The pathologyical changes of the two layers are through a coupling diffusion process.