Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, 64108, United States.
Arch Oral Biol. 2012 Dec;57(12):1585-94. doi: 10.1016/j.archoralbio.2012.04.014. Epub 2012 May 19.
To investigate the ultrastructure and chemical composition of the dentine-enamel junction and adjacent enamel of minimally processed third molar tooth sections.
Undecalcified human third molar erupted teeth were sectioned and etched with 4% EDTA or 37% phosphoric acid prior to visualization by scanning electron microscopy. Confocal Raman spectroscopy was carried out at 50 μm and more than 400 μm away from the dentine-enamel junction before and after mild etching.
A novel organic protein-containing enamel matrix layer was identified for the first time using scanning electron microscopy of etched bucco-lingual sections of crowns. This layer resembles a three-dimensional fibrous meshwork that is visually distinct from enamel "tufts". Previous studies have generally used harsher solvent conditions which likely removed this layer and precluded its prior characterization. The shape of the organic enamel layer generally reflected that of sheath regions of enamel rods and extended from the dentine-enamel junction about 100-400 μm into the cuspal enamel. This layer exhibited a Raman CH stretching peak at ∼2931 cm(-1) characteristic of proteins and this signal correlated directly with the presence and location of the matrix layer as identified by scanning electron microscopy.
The enamel protein layer was most prominent close to the dentine-enamel junction and was largely absent in cuspal enamel >400 μm away from the dentine enamel junction. We hypothesize that this protein containing matrix layer could provide an important biomechanical linkage between the enamel and the dentine-enamel junction and by extension, with the dentine, of the adult tooth (246 words).
研究微创第三磨牙牙体组织切片牙本质-釉质交界处及其相邻釉质的超微结构和化学成分。
未脱矿的人类第三磨牙萌出牙体组织切片，用 4% EDTA 或 37%磷酸酸蚀后，用扫描电子显微镜观察。在距牙本质-釉质交界处 50 μm 和 400 μm 以上的位置，用共焦拉曼光谱仪对轻度酸蚀前后的牙釉质进行检测。
首次通过扫描电子显微镜观察牙冠颊舌向酸蚀剖面，发现了一种新型的含蛋白质的牙釉质基质层。该层类似于三维纤维网状结构，与牙釉质“毛簇”明显不同。先前的研究通常使用更苛刻的溶剂条件，这可能会去除该层，从而无法对其进行先前的特征描述。有机牙釉质层的形状通常反映了牙釉质杆鞘区的形状，从牙本质-釉质交界处延伸约 100-400 μm 进入牙尖釉质。该层在约 2931 cm(-1)处表现出 CH 伸缩峰，这是蛋白质的特征峰，该信号与扫描电子显微镜识别的基质层的存在和位置直接相关。
牙釉质蛋白层在靠近牙本质-釉质交界处最为明显，而在距离牙本质-釉质交界处 400 μm 以外的牙尖釉质中则基本不存在。我们假设，这种富含蛋白质的基质层可以为牙釉质和牙本质-釉质交界处，以及成人牙齿的牙本质提供重要的生物力学连接（246 字）。
