New Cavity Forms in Deciduous Molars which maximized Dentin Thickness between Cavity and Pulp Chamber

本研究是在前人研究的基础上进行的。一种使用人的拔除乳磨牙，确保防止充填材料脱落和防止牙髓坏死的理想洞的形成方法。空腔的理想形式被定义为在任何测量点处空腔与牙髓室之间具有至少约1 mm的距离并且在有效位置处具有固位凹槽的空腔。然后，对现有的窝洞制备方法进行了评价，并对乳牙嵌体脱落的原因进行了分析。(1)在第一乳磨牙牙槽嵴三角形处加1.5mm深的窝洞，窝洞深度为1.0mm。上、下第一乳磨牙龈壁宽度0.6 ~ 0.7mm，外固位形式，其洞形较理想。(2)近中颊三角嵴与中央沟交界处1.4mm处和龈壁宽度1.0mm处的洞型是上、下第二乳磨牙理想的洞型。(3)传统的窝洞制备深度为1.5mm的洞型，洞壁过深，部分牙体牙髓外露。(4)导致嵌体脱落的腔体结构是由于腔体宽度较大，深度过浅和固位形式不足。

This study was carried for the purpose to contrive on the basis of our earlier studies. a method for formation of ideal cavity which ensures prevention of detachment of the filling material and prevention of pulp death, using human extracted deciduous molars. The ideal form of cavity is defined as one which has a distance of at least approximately 1 mm between the cavity and the pulp chamber at any point of measurement and which has a retentional grooves at the effective positions. And then, the evaluation of existing methods for cavity preparation and the causes of inlay detachment in deciduous solars, were also studied.Results obtained were as follows.(1) When a cavity was formed to the depth of 1.0 mm at the central foosa (adding the depth of 1.5 mm at the triangular ridge in the first deciduous molar). the width of 0.6 - 0.7 mm at the gingival wall and the outer retentional forms in the upper and lower first deciduous molars, their cavity fores were ideal.(2) The cavity forms which was set at 1.4 mm at the intersection of mesiobuccal triangular ridge and the central groove and at 1.0 am at the width of the gingival wall, were desired forms for both upper and lower second deciduous molars.(3) The conventional cavity forms which were prepared to the depth of 1.5 mm at the central fossa, had too deep cavity walls and the pulp was exposed in some teeth.(4) The cavity configuration that resulted in the falling-out of inlay was due to the larger cavity width, being too shallow in depth and insufficient retentional form.