A study of the cavity design in restoration with adhesive composite resin in primary molars

目的：在1998~1999年的研究中，我们试图建立洞穴的轮廓形状，尽量减少从边缘微渗漏，不留下未聚合的树脂，将切割保持在最小的量，并确定足够的棒材来准备这样的洞穴。在本年度，由于上述试棒已经制作完成，我们在幼犬身上进行了窝洞制备，并比较了用常规棒材和试验棒制备的试棒对牙髓组织的影响。材料和方法：选用2个月龄杂种犬9只。在戊巴比妥钠腹内麻醉下，用试验杆在右下第三磨牙上制作深度约为0.5 mm的牙洞，而在左侧磨牙上用FG301钻杆制作牙洞。接下来，在这些空洞的地板上放置止动块，并填充高粘结碳素水泥来覆盖它。在…的第3、14和28天S进一步做好窝洞准备后，拔除下颌骨，用Plank-Rychlo液固定后脱钙。然后，标本脱水，石蜡包埋，切成30μm厚的切片，苏木素和曙红染色。观察牙髓组织的变化。结果与讨论：空洞制备后3d，对照组和实验组均可见空洞附近毛细血管扩张、成牙本质细胞消失或空泡化。这些变化在对照组中更为显著。14天时，成牙本质细胞空泡样变性消失，但邻近洞底的牙髓组织可见明显的炎性细胞浸润和毛细血管扩张。这些变化在对照组中也有更强烈的表达。在28天时，这些炎性体征仅在对照组中持续存在。根据目前的结果，该粘接复合树脂的实验测试棒适用于临床使用。较少

PURPOSE : In our studies from 1998 to 1999, an attempt to establish the outline form of the cavity was made minimizing microleakage from the margin, without unpolymerized resin leaving behind, keeping the cutting to a minimum amount, and to decide the kind of bar adequate to prepare such a cavity. During the concerned year, since the trial bar as above mentioned had already been made, we performed the cavity preparation in infantile dogs and compared the effects on the pulpal tissues between those prepared with a conventional bar and with the trial bar. MATERIAL AND METHODS : Nine 2-month-old mongrel dogswere used. Under intra-abdominal anesthesia with pentobarbital, tooth cavities of approximately 0.5 mm depth were prepared in the right lower third molars using the trial bar, whereas in the left teeth the cavities were formed with a FG301 diamond bar. Next, a stopping was placed in the floor of these cavities and High-bond Carbo-cement ^<TM> was filled to cover it. At 3, 14 and 28 day … More s after the cavity preparation, mandibles were extirpated and decalcified with Plank-Rychlo solution following fixation. Then, the specimens were dehydrated, embedded in paraffin, cut into 30 μm-thick sections and stained with hematoxylin and eosin. Observation was made on the pulpal tissue changes. RESULTS AND DISCUSSION : At 3 days after the cavity preparation, dilatation of the blood capillaries and disappearance or vacuolar degeneration of the odontoblasts in the proximity of the cavities were observed in both the control and experimental groups. These changes were more significant in the control group. At 14 days, although the vacuolar degeneration of odontoblasts was no more observed, marked inflammatory cell infiltration and capillary dilatation were revealed in the pulpal tissue adjacent to the cavity floor. These changes were also more intensely expressed in the control group. At 28 days, these inflammatory signs still persisted only in the control group. Base on the present results, it is concluded that this experimentally tested bar for the adhesive composite resin is applicable to the clinical usage. Less