McIntyre J M, Featherstone J D, Fu J
Department of Dentistry, University of Adelaide.
Aust Dent J. 2000 Jun;45(2):97-102. doi: 10.1111/j.1834-7819.2000.tb00248.x.
Artificial caries lesions were produced in roots of teeth using an acetate buffer system, when the layer of cementum was either normal in thickness, excessively thickened by hypercementosis, or had been removed completely. The rates of lesion progression were measured in each case using polarized light microscopy to measure lesion depth. Analysis of calcium (Ca) and phosphorus (P) loss during the demineralizing process was carried out. The removal of cementum was found to significantly increase the initial rate of penetration of the lesion into the root, although this rate progressively reduced to a level consistent with that found in normal roots after seven days of demineralization. The overall depth remained consistently greater than that observed in normal roots, or when lesions were produced entirely within hyperplastic cementum. Chemical analysis also showed removal of cementum resulted in an initial doubling of the Ca and P lost from the root surface. Prior direct exposure of segments of normal roots to the oral environment was found not to significantly alter the rate of artificial lesion progression, in comparison with that in the originally protected segment of the root surface. It was concluded that an intact cementum layer has the intrinsic ability to protect the underlying dentine of exposed tooth roots against acidic demineralization and that prior exposure to the oral environment does not significantly alter this ability.
使用醋酸盐缓冲系统在牙齿根部制造人工龋损，此时牙骨质层的厚度要么正常，要么因牙骨质增生而过度增厚，要么已被完全去除。在每种情况下，使用偏光显微镜测量龋损深度来测定病变进展速率。对脱矿过程中钙（Ca）和磷（P）的流失进行了分析。发现去除牙骨质会显著增加病变侵入牙根的初始速率，尽管在脱矿七天后，该速率会逐渐降低至与正常牙根中发现的速率一致的水平。总体深度始终大于在正常牙根中观察到的深度，或者大于在增生性牙骨质内完全形成病变时的深度。化学分析还表明，去除牙骨质会导致牙根表面钙和磷的流失量最初增加一倍。与牙根表面原本受保护的部分相比，发现正常牙根部分预先直接暴露于口腔环境不会显著改变人工病变的进展速率。得出的结论是，完整的牙骨质层具有保护暴露牙根下方牙本质免受酸性脱矿的内在能力，并且预先暴露于口腔环境不会显著改变这种能力。
