Department of Cariology and Operative Dentistry, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Department of Cariology and Operative Dentistry, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Department of Operative Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
Dent Mater. 2019 Apr;35(4):e74-e82. doi: 10.1016/j.dental.2019.01.008. Epub 2019 Feb 13.
The purpose of this study was to detect and investigate the association of enamel microcracks with demineralization at proximal contact areas of premolars, using 3D swept-source optical coherence tomography (SS-OCT).
Extracted maxillary and mandibular premolars (n=50 each), without any visible tooth cracks, were examined for demineralization of interproximal contact areas, using the International Caries Detection and Assessment System (ICDAS). SS-OCT was used to evaluate demineralization and detect microcracks. Demineralization progression was divided into 4 types by depth: 0 for sound enamel and Type I, II, and III for enamel demineralization penetrating into the outer third, the middle third, and the inner third of the enamel thickness, respectively. Enamel microcracks were classified according to the predominant crack pattern: Type O, no cracks; Type A, subsurface microdefects; Type B, enamel microcrack running along the direction of the enamel prism; Type C, enamel microcrack running transverse to the enamel prism direction; and Type D, a combination of patterns A, B, and C. SS-OCT findings were confirmed by confocal laser scanning microscopy observation.
Microcracks confined within the superficial enamel in proximal contact areas were seen as bright lines on SS-OCT. There were significant positive correlations among ICDAS codes, demineralization levels, and microcrack distribution (p≤0.001). The mesial side of maxillary premolars showed significantly more demineralization (n=36) and microcracks (n=27) than that of the mandibular premolars (n=20 and n=14, respectively; p<0.001).
The presence of microcracks within the superficial enamel in proximal contact areas could be determined using SS-OCT, and correlated with the level of demineralization. 3D SS-OCT is a valuable diagnostic tool for comprehensive assessment of microstructural changes related to enamel demineralization and crack development.
本研究旨在使用 3D 扫频源光学相干断层扫描（SS-OCT）检测和研究磨牙近中接触区釉质微裂与脱矿的关系。
分别对 50 颗上颌和下颌前磨牙（每颗牙）进行无可见牙裂的近中接触区脱矿检查，采用国际龋病检测与评估系统（ICDAS）进行。使用 SS-OCT 评估脱矿情况并检测微裂。根据深度将脱矿进展分为 4 种类型：0 表示正常釉质，I 型、II 型和 III 型分别表示釉质脱矿穿透釉质厚度的外三分之一、中三分之一和内三分之一。根据主要裂纹模式对釉质微裂进行分类：O 型，无裂纹；A 型，表面下微缺陷；B 型，沿釉柱方向运行的釉质微裂；C 型，与釉柱方向垂直运行的釉质微裂；以及 D 型，A、B 和 C 型的组合。SS-OCT 结果通过共聚焦激光扫描显微镜观察进行确认。
SS-OCT 上近中接触区釉质内的微裂显示为亮线。ICDAS 编码、脱矿程度和微裂分布之间存在显著的正相关关系（p≤0.001）。上颌前磨牙的近中面显示出明显更多的脱矿（n=36）和微裂（n=27），而下颌前磨牙的脱矿（n=20）和微裂（n=14）明显较少（p<0.001）。
SS-OCT 可确定近中接触区釉质表面下微裂的存在，并与脱矿程度相关。3D SS-OCT 是评估与釉质脱矿和裂纹发展相关的微观结构变化的一种有价值的诊断工具。
