Lee Chulsung, Hsu Dennis J, Le Michael H, Darling Cynthia L, Fried Daniel
University of California, San Francisco, San Francisco, CA 94143-0758.
Proc SPIE Int Soc Opt Eng. 2009 Mar 6;7162(1). doi: 10.1117/12.816863.
Previous studies have demonstrated that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to image the remineralization of early artificial caries lesion on smooth enamel surfaces of human and bovine teeth. However, most new dental decay is found in the pits and fissures of the occlusal surfaces of posterior dentition and it is in these high risk areas where the performance of new caries imaging devices need to be investigated. The purpose of this study was to demonstrate that PS-OCT can be used to measure the subsequent remineralization of artificial lesions produced in the pits and fissures of extracted 3(rd) molars. A PS-OCT system operating at 1310-nm was used to acquire polarization resolved images of occlusal surfaces exposed to a demineralizing solution at pH-4.5 followed by a fluoride containing remineralizing solution at pH-7.0 containing 2-ppm fluoride. The integrated reflectivity was calculated to a depth of 200-μm in the entire lesion area using an automated image processing algorithm. Although a well-defined surface zone was clearly resolved in only a few of the samples that underwent remineralization, the PS-OCT measurements indicated a significant (p<0.05) reduction in the integrated reflectivity between the severity of the lesions that were exposed to the remineralization solution and those that were not. The lesion depth and mineral loss were also measured with polarized light microscopy and transverse microradiography after sectioning the teeth. These results show that PS-OCT can be used to non-destructively monitor the remineralization potential of anti-caries agents in the important pits and fissures of the occlusal surface.
先前的研究表明，偏振敏感光学相干断层扫描（PS-OCT）可用于对人和牛牙齿光滑釉质表面早期人工龋损的再矿化进行成像。然而，大多数新发龋齿见于后牙牙合面的窝沟处，正是在这些高风险区域需要研究新型龋齿成像设备的性能。本研究的目的是证明PS-OCT可用于测量拔除的第三磨牙窝沟处人工龋损的后续再矿化情况。使用一台工作在1310纳米的PS-OCT系统获取牙合面的偏振分辨图像，该牙合面先暴露于pH值为4.5的脱矿溶液中，随后再暴露于pH值为7.0、含2 ppm氟化物的含氟再矿化溶液中。使用自动图像处理算法计算整个病变区域200微米深度范围内的积分反射率。尽管在仅少数经过再矿化的样本中能清晰分辨出明确的表面区域，但PS-OCT测量结果表明，暴露于再矿化溶液的病变与未暴露的病变相比，积分反射率有显著（p<0.05）降低。在牙齿切片后，还使用偏振光显微镜和横向显微放射摄影测量了病变深度和矿物质流失情况。这些结果表明，PS-OCT可用于无损监测牙合面重要窝沟处抗龋剂的再矿化潜力。
