Er：YAG激光在龈下楔状缺损治疗中的临床应用

目的评价Er：YAG激光在治疗龈下楔状缺损中的应用。方法选择有两个洞缘位于龈下1mm～2mm的楔状缺损患牙的患者共20例。对照组以车针预备窝洞,电刀切除牙龈的方法进行牙体预备,实验组以Er：YAG激光预备窝洞并同时切除牙龈的方法完成预备。以VAS评分记录术中不舒适程度,术后随访12个月检查充填体情况。结果试验组VAS平均值为42.3±12.1,对照组VAS平均值为61.1±17.0,两组间差异有显著性（P〈0.01）。术后1周,对照组有1例发生龈退缩。12个月,试验组和对照组分别有2例和3例出现边缘不密合和边缘着色（P〉0.05）。结论激光行龈下楔状缺损牙体预备的方法可以有效减轻术中不适,对充填体质量无副作用。     

不同参数的Er：YAG激光离体牙窝洞预备的形态学观察

目的：观察Er：YAG激光对离体人牙进行窝洞预备后的形态学改变,比较不同的能量设置及不同的水气比作用下的预备效果。方法：将10个无龋的离体磨牙随机分为5组（n＝2）,分别用不同Er：YAG激光参数进行窝洞预备。扫描电镜下观察牙釉质和牙本质的形态学改变。结果：经Er：YAG激光照射后,牙釉质呈现出一个粗糙不平的表面,牙本质层清洁,小管开放。在总功率相近的情况下,当水冷却降到50％或切割牙釉质时脉冲能量增加到700 mJ、切割牙本质时脉冲能量增加到400 mJ时,牙釉质及牙本质表面可发生部分熔融改变。结论：Er：YAG激光使用合适的参数进行牙体硬组织的切割安全有效,但在功率相近的情况下,水冷却不足或能量过大（牙釉质＞700 mJ,牙本质＞400 mJ）可损伤牙体组织。     

Er：YAG激光在龋病治疗时消除疼痛疗效观察

目的：探讨Er:YAG激光在龋病治疗中的止痛效果。方法：使用Er:YAG激光治疗9例龋齿、观察临床效果及疼痛情况。结果：治疗过程中实验组患者疼痛得分平均为0．22且均未麻醉,而牙钻组疼痛得分平均为1．6,且2例进行麻醉。结论Er:YAG激光可以较好地解决龋齿治疗中的疼痛问题。     

Er:YAG激光在龋病诊治应用方面的研究进展

Er：YAG激光是一种新型的牙体硬组织切割激光,在龋病诊治中的应用正不断深入。本文就Er：YAG激光切割牙体硬组织的机制、牙髓反应,以及在龋病诊断、预防、治疗方面的应用作一综述。     

Er：YAG激光备洞与树脂充填微渗漏的实验研究

目的：评价Er：YAG激光备洞对树脂充填材料边缘微渗漏的影响。方法：选择48颗年轻前磨牙随机分成4组,每组12颗牙,用Er：YAG激光或高速牙钻制备ⅴ类洞。对照组：牙钻备洞＋35%磷酸酸蚀;实验1组：激光备洞＋35%磷酸酸蚀;实验2组：激光备洞＋自酸蚀粘接;实验3组：单纯激光备洞。树脂充填,经冷热循环试验后染色24h,体视显微镜下观察微渗漏,统计学处理数据。结果：龈壁的染料渗透,4组间无统计学差异;壁的染料渗透,以实验3组较明显,与对照组、实验1、2组有统计学差异（P〈0.05）;各组内壁的染料渗透均比龈壁轻,但没有统计学差异。结论：Er：YAG激光备洞,35%磷酸酸蚀或自酸蚀粘接处理可减少洞壁与树脂充填边缘的微渗漏。     

Nd：YAG激光照射对牙周病患牙根面的影响

目的：研究Nd:YAG激光照射对未处理过的和用超声波或手工器械辞治过的牙周病患牙根面的影响,方法：选择因严重牙周病而须除除的单根牙18颗,随机平均分为6组,在临床麻醉下分别先后作如下治疗：超声波刮治＋激光照射,激光照射＋超声波刮治;手工器械刮治＋激光照射,激光照射＋手工器械刮治;超声波刮治;手工器械刮治,然后拔除患牙作扫描电镜观察,结果：单纯用超声波或手工器械刮治过的牙根表面均有明显的涂层,而用激光（20pps,2.0W,3min)照射,无论是在辞治前还是刮治后,均有助于根面涂层的去除,但激光对牙根表面结构有不同程度的影响。结论：先用Nd:YAG激光照射,再行龈下辞治,牙根表面的涂层被清除,而结构改变最小。     

Er: YAG激光在口腔医学中的应用

Er：YAG激光属于中红外线激光,是新一代水动力生物激光系统,拥有适合切除口腔软硬组织的特点,与传统治疗方法相比具有许多优点,可减轻治疗过程中的不适感和疼痛,患者更易接受。因铒激光在牙科治疗中的研究和应用的不断深入,本文对其工作原理及其在口腔治疗中的优势和应用进行综述。     

Nd：YAG激光清除龋坏牙本质的作用：扫描电镜研究

清除龋坏牙本质是Ｎｄ：ＹＡＧ激光在口腔科的重要应用之一。本研究目的的评价Ｎｄ：ＹＡＧ激光应用于清除龋坏牙本质的效果以及对龋坏下正常牙本质形态改变的应用。实验用Ｎｄ：ＹＡＧ激光照射处理离体牙牙本本质浅龋区,然后对实验区作扫描电镜观察。结果发现：激光参数在１５ｐｐｓ,６０ｍＪ／ｐ时,牙本质表面龋坏组织基本清除干净,牙本质小管口缩小,管间牙本质粗糙。     

脉冲Er：YAG激光照射对窝沟封闭微渗漏的影响

目的观察脉冲Er：YAG激光照射对窝沟封闭微渗漏的影响。方法选用因正畸需要拔除的上颌第一双尖牙30颗,随机分为A、B、C组,每组10颗。A组为对照组,采用35%磷酸酸蚀后窝沟封闭;B组采用脉冲Er：YAG激光扫描式照射面窝沟,吹干后直接进行封闭;C组先采用脉冲Er：YAG激光扫描式照射面窝沟,再进行35%磷酸酸蚀后窝沟封闭。三组样本通过染料浸染后使用光学显微镜观察窝沟封闭微渗漏。结果 B组微渗漏显著高于A组和C组,A组和C组微渗漏差别无统计学意义。结论在窝沟封闭操作中,脉冲Er：YAG激光照射不能替代磷酸酸蚀。     

根管治疗中应用Nd:YAG 激光的扫描电镜观察

目的 探讨Nd：YAG激光在根管治疗中的应用。方法 选用28个离体单根牙，随机分为4组。对照组不做处理。常规组进行根管扩大和根管冲洗，激光组经根管扩大后，用Nd：YAG激光1．5W，20pps分别照射15s和30s，并用扫描电镜观察。结果 激光照射15s组玷污层被去除，牙本质小管封闭和半封闭。激光照射30s组牙本质过分熔融，牙本质小管口开放。结论 Nd：YAG激光在根管治疗中的应用是可行的。     

Nd:YAG激光和Er:YAG激光对根管内粪肠球菌杀灭效果的研究

［摘要］ 目的 观察Nd:YAG激光、Er:YAG激光及两者联用对根管内粪肠球菌的杀灭效果。方法 选取离体牙建立粪肠球菌感染模型,随机分为五组：A组：生理盐水组;B组：1%次氯酸钠溶液组;C组：Nd:YAG激光组;D组：Er:YAG激光组;E组：Nd:YAG激光+Er:YAG激光组。通过细菌培养和扫描电镜观察对比各组的杀菌效果。结果 细菌培养和扫描电镜结果显示：A组杀菌率最低,B组杀菌率最高,E组次高。除C组和D组间杀菌率相近外（P>0.05）,各组间均有统计学差异（P<0.05）。结论 Nd:YAG激光和Er:YAG激光均有一定的根管杀菌效果,两者联用效果更佳,可作为传统消毒方法的补充。     

Efficacy of subgingival calculus removal with Er:YAG laser compared to mechanical debridement: an in situ study

OBJECTIVES: The aim of the present study was to compare the effectiveness of subgingival calculus removal from periodontally involved root surfaces with an Er:YAG laser compared to hand instrumentation in situ. METHODS: The mesial and distal surfaces of 30 single-rooted teeth with untreated periodontitis were treated either by hand instrumentation (scaling and root planing (SRP)) or by Er:YAG laser irradiation with the aim of achieving a calculus-free root surface. Subgingival plaque samples were obtained before and immediately after treatment for microbiological evaluation by culture and DNA probe analysis. The teeth were extracted and the residual calculus was measured by means of digitized planimetry. The morphology of the root surface was evaluated by scanning electron microscopy, and undecalcified sections were analyzed to determine residual calculus and the extent of cementum removal following both treatments. RESULTS: Following laser irradiation, 68.4+/-14.4% of the root surface was calculus free in contrast to 93.9+/-3.7% after SRP when both treatments were performed for the same time (2:15+/-1:00 min). If laser irradiation was allowed twice the time used for hand instrumentation, 83.3+/-5.7% of the root surface was devoid of calculus. The effectiveness of both treatments was not related to initial probing depth. The histologic evaluation showed that after SRP 73.2% of root dentin was completely denuded from cementum, while only a minimal cementum reduction was apparent after laser irradiation. Both treatment modalities resulted in a similar reduction of periodontopathogens. DISCUSSION: The present investigation could demonstrate the in vivo capability of the Er:YAG laser to remove calculus from periodontally involved root surfaces, although the effectiveness did not reach that achieved by hand instrumentation. The lack of cementum removal in contrast to SRP may qualify the laser as an alternative approach during supportive periodontal therapy.     

Morphology, chemical structure and diffusion processes of root surface after Er:YAG and Nd:YAG laser irradiation

OBJECTIVES: The aim of this in vitro study was to evaluate the effects of Er:YAG and Nd:YAG lasers on morphology, chemical structure and diffusion processes of the root surface. MATERIAL AND METHODS: 60 root samples were irradiated for 1 min each either with 60 mJ/p, 80 mJ/p and 100 mJ/p using Er:YAG laser or with 0.5W, 1.0W and 1.5W using Nd:YAG laser. Scanning electron microscopy (SEM) was used to determine the morphology, infrared (IR) spectroscopy to assess the alterations in chemical structure and one dimensional electron paramagnetic resonance imaging (1-D EPRI) was used to estimate the diffusion coefficients in dental root samples. RESULTS: Er:YAG laser treatment resulted in deep crater formation with exposed dentin. Morphological alterations of root surface after Nd:YAG laser irradiation included cracks, crater formation, meltdown of the root mineral and resolidified porous globules formation. Er:YAG laser failed to alter the intensity of Amide peaks I, II or III. In contrast, treatment with Nd:YAG laser, using the highest power setting of 1.5W, reduced the intensity of Amide peak II and III in comparison to the control. The diffusion coefficients were increased significantly in all Er:YAG and Nd:YAG treated root samples. CONCLUSION: This study demonstrated that Er:YAG laser influences only on morphology and diffusion processes of root surfaces, while Nd:YAG laser also alters the chemical structure of root proteins.     

Evaluation of selective calculus removal by a fluorescence feedback-controlled Er:YAG laser in vitro

OBJECTIVES: To evaluate the removal of subgingival calculus and dental hard tissues depending on the threshold level of a fluorescence feedback-controlled Er:YAG laser. MATERIAL AND METHODS: Twenty teeth with calculus on the root surface were treated with an Er:YAG laser. Laser settings were 140 mJ and 10 Hz. The initial fluorescence threshold level of 5 [U] was reduced at intervals of 1 [U] for every laser treatment. Areas of residual calculus (RC) were evaluated using a surface analysis software. Loss of dental hard tissues was assessed by histomorphometric analysis of undecalcified ground sections. RESULTS: Using a threshold value of 5 [U], the median amount of RC was 11% (0-78%). By lowering the threshold levels, the amount of RC decreased [level 1 [U]: 0% (0-26%)]. The laser-treated root surfaces revealed a statistically significant reduction of the cementum thickness [median: 80 microm (0-250)] compared with the non-treated opposite side [median: 90 microm (30-250)] (p<0.05). CONCLUSION: The amount of RC following laser irradiation depends on the fluorescence threshold level for a feedback-controlled Er:YAG laser. It might be suggested that this laser system may be used with a threshold level even lower than 5 [U] without removing a clinically relevant amount of root cementum.     

Er:YAG激光联合生物活性玻璃对封闭牙本质小管效果的研究

目的 研究Er:YAG激光联合生物活性玻璃脱敏剂对牙本质小管的封闭率和抗老化效果,探讨两者联合应用时的最佳顺序.方法 制作45个敏感牙本质模型,将样本随机分成5组,前四组平均每组10颗,应用不同方法进行牙本质脱敏处理:A:Er:YAG激光组;B:生物活性玻璃组;C:Er:YAG激光+生物活性玻璃组;D:生物活性玻璃+E...     

Visualization of irrigant flow and cavitation induced by Er:YAG laser within a root canal model

Introduction

Laser-activated irrigation (LAI) has recently been introduced as an innovative method for root canal irrigation. However, there is limited information about the cleaning mechanism of an Er:YAG laser. In this study, we visualized the action of laser-induced bubbles and fluid flow in vitro to better understand the physical mechanisms underlying LAI.

Methods

An Er:YAG laser was equipped with a novel cone-shaped tip with a lateral emission rate of approximately 80%. Laser light was emitted at a pulse energy of 30, 50, or 70 mJ (output energy: 11, 18, or 26 mJ) and a repetition rate of 1 or 20 pulses per second, without air or water spray. Fluid flow dynamics in a root canal model were observed by using glass-bead tracers under a high-speed camera. Moreover, laser-induced bubble patterns were visualized in both free water and the root canal model.

Results

Tracers revealed high-speed motion of the fluid. A full cycle of expansion and implosion of vapor and secondary cavitation bubbles were clearly observed. In free water, the vapor bubble expanded for 220 microseconds, and its shape resembled that of an apple. In the root canal model, the vapor bubble expanded in a vertical direction along the canal wall, and bubble expansion continued for ≥700 microseconds. Furthermore, cavitation bubbles were created much more frequently in the canal model than in free water.

Conclusions

These results suggest that the cleaning mechanism of an Er:YAG laser within the root canal might depend on rapid fluid motion caused by expansion and implosion of laser-induced bubbles.