Studies on Marginal Leakage of Cavities Prepared by Er : YAG Laser

对V类窝洞出现微边缘渗漏的Li和未发现微边缘渗漏的MZ两种复合树脂进行充填。实验1：(1)仅用Er：YAG激光制作V类窝洞，磨牙不使用旋转切割器械。(2)仅用Er：YAG激光制作斜面。(3)对地洞和侧壁进行Er：YAG激光照射。采用酸蚀或不酸蚀两种方法分别对三种窝洞进行充填。试验二：对邻面龋病患者在前磨牙内制作隧道洞。(1)用旋转切割机制备Th隧道空洞。(2)用Er：YAG激光去除软牙本质，完成窝洞。这两种空洞的制作方法与试验1相同。结论：1.没有旋转切割器，Er：YAC激光很难制备出空洞。Er：YAC激光是去除软牙本质的有效方法。采用激光刻蚀的方法不稳定。有必要改变刻蚀时间和刻蚀方法，开发粘结剂。在隧道空洞中使用激光会增加微边缘渗漏。充填MZ的管腔常见于近端牙釉质颈壁的微小边缘渗漏。

Two kinds of Composite resin, LI that were seen micro-marginal leakage in class V cavities and MZ that were not recognized micro-marginal leakage, were filled. After 200 thermal scycles, Marginal leakage was tested by Mercox-Rohdamin Method.Test 1 : (1)The class V cavities were prepared only by Er : YAG Laser without rotar cutting instrumens in molar.(2)Only bevel were prepared by Er : YAG laser.(3)Er : YAG laser were irradiated at the floor cavity and the side wall. These thre kinds of cavities were filled with composite resin with or without etching method.Test 2 : The tunnel cavities were prepared in premolar for proximal caries. (1)Th tunnel cavities were prepared by rotaly cutting instrument. (2)Soft dentin was removet by Er : YAG laser, and cavities were finished. These two kinds of cavities were done th ame way as in Test 1.Results were as follows.1. It is difficult to prepare cavity by Er : YAG laser without rotary cutting instrument Er : YAC laser is useful for removing soft dentin.2. The method using laser etching is unstable. It is necessary to change etching tim and etching method, and to develop bonding agents. Using Laser in tunnel cavit incresed micro-marginal leakage.3. unnel cavities filled with MZ are often observed micro-marginal leakage at th proximal enamel cervical wall.