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

这项研究是在我们早期研究的基础上进行的。一种利用人摘出的乳牙形成理想腔的方法，该方法可确保防止充填材料脱离和防止牙髓死亡。空腔的理想形式被定义为在任何测量点在空腔和浆腔之间具有至少约1mm的距离，并且在有效位置具有保留槽。然后，对现有的空腔制备方法进行了评价，并对落叶太阳中嵌体脱落的原因进行了研究。所得结果如下：(1)在中央齿槽处形成深度为1.0 mm的空腔（在第一乳牙三角脊处增加深度为1.5 mm）。上、下两颗第一乳牙的龈壁宽度为0.6 ~ 0.7 mm，外固位形态为理想的牙洞。(2)上、下第二乳磨牙的理想牙槽形态为中颊三角脊与中央沟交点处1.4 mm和龈壁宽度1.0 am。(3)常规牙槽结构在中窝深度为1.5 mm时，牙槽壁过深，部分牙髓外露。(4)导致嵌体脱落的空腔形态主要是由于空腔宽度过大、深度过浅、保留形式不足。

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.