Er：YAG激光与传统机械去腐制备洞形的体外可行性比较

目的　为Er：YAG激光去除龋损和粘接修复的可行性提供更多的证据。方法　选取南京医科大学附属口腔医院口腔颌面外科门诊拔除的36颗龋坏深及牙本质的磨牙。每个离体牙的龋损都被切成大小相等的两份，分别纳入对照组(机械预备组)和实验组(Er：YAG激光组)。通过测量微拉伸粘接强度(mTBS)、微渗漏深度、观察组织学形貌、微观形态和测量操作时间比较了Er：YAG激光与传统机械法在这些方面的特性。结果　实验组的微拉伸粘接强度高于对照组(n=13，P<0.05)，而平均微渗漏深度低于对照组，但差异无统计学意义(n=13，P>0.05)。实验组残留感染牙本质小管少于对照组(n=6，P<0.01)。扫描电镜观察显示，实验组牙本质小管开放、清晰、裸露，而经机械预备的牙本质表面有玷污层(n=4)。实验组的去龋时间明显长于对照组(n=36，P<0.05)。结论　虽然去龋时间较长，但Er：YAG激光用于窝洞预备较传统机械法有更高的微拉伸粘接强度和更少的感染牙本质小管残留。因此，Er：YAG激光是一种合适的临床去龋方法。

An in vitro feasibility study comparing Er:YAG laser and conventional mechanical devices for cavity preparation

Purpose To provide more evidence for the feasibility of an erbium-doped yttrium-aluminum-garnet (Er:YAG) laser in caries removal and adhesive restoration.Methods Thirty-six freshly extracted human molars with dentin caries were used. Each carious lesion of the isolated tooth was cut into equal-sized halves. One half was assigned to the study groups (Er:YAG laser irradiation group) and the other half to the control groups (mechanical excavation group). Five experiments were conducted to compare the characteristics of the Er:YAG laser with those of conventional mechanical devices in terms of microtensile bond strength (mTBS), microleakage, histology, micromorphology, and excavation time.Results The study groups showed higher mTBS than the control groups (n = 13, p < 0.05). The mean microleakage depth of the study groups was lower than that of the control group, but without significant difference (n = 13, p > 0.05). The study group had less remaining infected dentin tubules than the control group (n = 6, p < 0.001). Scanning electron microscope evaluation of samples in the study group showed extensive clear and exposed dentinal tubules, while smear layers were observed on dentin surface treated by a bur (n = 4). However, the study group showed longer times for caries removal than the control groups (n = 36, p < 0.05).Conclusion Although the time for caries removal is longer, the Er:YAG laser used in cavity preparation was superior to conventional mechanical devices in terms of higher mTBS and less remaining infected dentin tubules. Therefore, the Er:YAG laser is a suitable alternative clinical treatment for caries removal.