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

将两种复合树脂，LI和MZ分别填充在V类洞中观察到微边缘渗漏和未观察到微边缘渗漏。实验1：（1）在磨牙上仅用Er：YAG激光预备V类洞，不使用旋转切削器。（2）Er：YAG激光只制备斜面。(3)Er：YAG激光照射底腔和侧壁。实验2：在前磨牙制备近端龋隧道洞。(1)Th用旋转切割器制备隧道洞。（2）用Er：YAG激光去除软质牙本质，修整洞形。这两种型腔的制作方法与试验1相同，结果如下：1. Er：YAG激光在无旋转切割器的情况下很难制备窝洞，Er：YAC激光是去除软质牙本质的有效方法.使用激光蚀刻的方法是不稳定的。因此，需要改变刻蚀时间和刻蚀方法，并研制键合剂。在隧道腔中使用激光会增加微边缘泄漏。3. MZ充填的牙槽窝常在近端釉质颈壁处观察到微边缘渗漏。

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.