脉冲Nd:YAG激光照射对牙釉质粘结性能的影响

目的 :探讨脉冲Nd :YAG激光作为牙体表面处理技术对牙釉质粘结性能的影响。方法 :分别用 1W、2 0Hz,1W、15Hz,1.5W、2 0Hz,1.5W、15Hz,2W、15Hz共 5个能量输出组照射离体牙釉质表面 ,测定其与复合树脂的抗张粘结强度 ,并与未处理组、35 %磷酸酸蚀组进行对照。结果 :激光照射组中输出能量为 1W、15Hz时抗张粘结强度最高 (3.87± 1.91MPa) ,其次是 1W、2 0Hz(3.4 3± 1.4 8MPa) ,两组间无显著差异 (P >0 .0 5 ) ,但都显著高于其它三个激光照射组及未处理组 (P <0 .0 5 )。酸蚀组的抗张粘结强度最高 (8.5 0± 3.0 2MPa) ,显著高于其它 6个实验组(P <0 .0 5 )。结论 :脉冲Nd :YAG激光处理牙釉质表面可改善粘结性能 ,抗张粘结强度受激光输出能量的影响 ,当激光输出能量为 1W、15Hz时抗张粘结强度最高 ,但低于酸蚀组。脉冲Nd :YAG激光能否作为一种牙釉质表面处理技术应用于临床尚需进一步研究     

Nd:YAG激光对不同水门汀与牙本质间边缘微渗漏的影响

目的:评价Nd:YAG激光对不同水门汀与牙本质之间边缘微渗漏的影响。方法:选用人离体磨牙48颗,间接法制作树脂嵌体,随机分为激光组和对照组,激光组使用80 mJ、10 Hz脉冲Nd:YAG激光照射后,分别用6种水门汀粘结树脂嵌体。全部试件放在37℃生理盐水中7 d,并冷热循环300次后,放置于0.5%的品红溶液中染色24 h,沿嵌体长轴纵剖后在根管显微镜下观察微渗漏情况,采用SPSS 17.0软件包对数据进行统计学处理。结果:6组牙本质经Nd:YAG激光照射后微渗漏程度均有降低趋势,且前2种水门汀有统计学差异(P<0.05)。另外,树脂水门汀与牙本质之间的微渗漏程度比水基水门汀低。结论:80 mJ、10 Hz脉冲Nd:YAG激光照射牙本质壁,可提高洞壁的密合度,减少微渗漏。     

脉冲Nd:YAG激光照射剂量对口腔溃疡组织中SOD活性和MDA含量的影响

目的:探讨脉冲Nd:YAG激光不同照射剂量对大鼠试验性口腔黏膜溃疡组织中超氧化物酶(SOD)、丙二醛(MDA)含量的影响.方法:健康Sprague-Dawley大鼠共56只,随机分为7组,1组作为正常对照组,6组建立口腔黏膜溃疡动物模型.按照分组给予不同剂最激光照射,末次治疗24 h后观察溃疡愈合时间.采用分光光度仪测定大鼠口腔黏膜组织中SOD活性、MDA的含量.结果:1.5 W 60 mJ、1.5w 80mJ激光组较溃疡组SOD活性显著增高(P<0.05).试验剂量范围内,1.5 w 60 mJ、1.5w 80 mJ激光组较溃疡组MDA的含量显著降低(P<0.05).1.5 W 60 mJ、1.5 W 80 mJ激光组与正常对照组SOD活性和MDA含量则没有显著性差异(P<0.05).结论:适合的剂量参数,采用适量脉冲Nd:YAG激光照射口腔黏膜溃疡能有效增加SOD活性.减少MDA含量,起到治疗口腔黏膜溃疡的作用.     

Nd:YAG 激光在直接盖髓术中的应用

目的 :观察研究脉冲Nd :YAG激光照射在直接盖髓术中的作用。方法 :选择门诊意外露髓的患者 10 0例 ,随机分为对照组和试验组。对照组采用传统的氢氧化钙直接盖髓术。试验组首先用脉冲Nd :YAG激光 (设置激光脉冲频率为 2 0Hz ,每脉冲能量 40mJ)照射穿髓孔区 5s,再以氢氧化钙封闭穿髓孔。病人于术后 2周、6月、12月分别复诊检查牙髓活力情况 ,记录盖髓术成功率。结果 :12月复诊时对照组成功率 76 % ,试验组成功率 92 % ,统计学分析两者有显著性差异。结论 :适当能量的Nd :YAG激光照射有助于直接盖髓术的成功。脉冲Nd :YAG激光不仅具有清除穿髓孔区牙体组织碎屑、使暴露的牙体组织表面凝固止血、对穿髓孔区灭菌消毒等功能 ,还具有促进牙髓组织细胞再生修复的作用。     

Nd:YAG激光对水门汀与牙本质剪切强度的影响

目的:评价脉冲Nd:YAG激光对水门汀与牙本质间剪切强度的影响,并观察激光照射前后的牙本质表面结构变化。方法:取人前磨牙30个,暴露牙本质粘接面形成60个测试样本,随机分为激光组和对照组。激光组以0.8W、10Hz脉冲Nd:YAG激光照射牙本质表面25sec,联合3种水门汀充填;对照组直接使用3种水门汀充填于牙本质表面,置于37℃生理盐水24h后,测试剪切强度,并进行统计学分析,在根管显微镜下观察断裂模式并分类。扫描电镜观察激光照射前后的牙本质表面形态。结果:聚羧酸锌组、玻璃离子组和树脂加强玻璃离子组在Nd:YAG激光照射前(后)的剪切强度分别为4.63±1.39(4.77±0.97)MPa、5.15±0.67(5.26±1.21)MPa和0.92±0.46(0.99±0.35)MPa,激光照射前后的差别均无统计学意义(P>0.05)。扫描电镜观察,0.8W、10Hz的Nd:YAG激光照射会使牙本质表面熔融,玷污层基本去除,大部分牙本质小管封闭,且在局部会出现裂纹。结论:Nd:YAG激光(0.8W、10Hz)处理牙本质,对聚羧酸锌和玻璃离子水门汀与牙本质间的粘接强度无影响。     

脉冲Nd:YAG激光照射对人牙釉质光滑面抗酸性的影响

目的：研究单独应用3种不同能量的普通脉冲Nd：YAG激光照射对光滑面牙釉质抗酸性的影响。方法：扫描电镜观察100、150、200mJ激光照射后离体人牙釉质表面的结构变化；并通过人工龋实验测量脱矿液中的釉质钙溶出量，确定单独用激光照射对牙釉质抗酸性的影响；X射线能谱仪(EDX)测量激光照射前后牙釉质中钙磷相对含量的比值的变化，初步探讨激光防龋的机制。结果：不同能量的激光照射可使表面牙釉质发生不同程度的熔化、熔融；100、150、200mJ激光照射组与末用激光照射组之间的釉质钙溶出量无明显差异(P＞0．O5)；激光照射可改变表面釉质的钙磷相对含量，100mJ组与150mJ、200mJ组相比照射前后钙磷比值的变化有显著的统计学差异(P＜0．05)。结论：不同能量的激光照射可使牙釉质表面发生不同程度的改变，但是本研究未发现单独用普通脉冲Nd：YAG激光照射有增强光滑面牙袖质抗酸性的效果。     

脉冲Nd:YAG激光根管内照射与牙根表面温度变化的关系

目的:探讨不同剂量的脉冲Nd:YAG激光根管内照射与牙根表面温度变化的关系及影响因素。方法:108颗离体单根管牙处理后分为3组。A组为同剂量激光根管内照射不同牙位的牙;B、C两组分别在15 Hz和20 Hz频率下分7种功率根管内照射,B组根管壁涂增效剂后再照射,测牙根表面中部的温度;C组加测根表面下部的温度。结果:¹同剂量激光根管内照射,下切牙较上切牙、尖牙和前磨牙根面温度显著升高(P<0101)。º20 Hz和15 Hz 照射组随激光功率增大牙根表面温度升高。»根管壁涂增效剂后各功率激光照射后根面升温显著增加(P< 0101)。¼同剂量激光照射,根尖部较根管中部温度升高更多。结论:在一定范围内,脉冲Nd:YAG激光根管内照射,牙根表面温度变化随功率、频率增大而增加;牙位和增效剂等对牙根表面温度变化有不同程度影响。     

不同参数Er:YAG激光照射对根面形态及粗糙度的影响

目的:探讨不同脉冲能量、不同照射时间的Er:YAG激光对牙根面形态、粗糙度的影响,为Er:YAG激光用于牙周治疗提供依据和参数指导。方法:将收集的牙周病患牙在釉牙骨界质根方2 mm切割制备成5 mm×5 mm×2 mm的牙体组织块共45个,随机分为9组。一组仅进行手工刮治,其余8组在手工刮治后分别接受不同脉冲能量及不同时间的激光照射,表面粗糙度仪测治疗前后粗糙度,扫描电镜观察治疗后根面形态。结果:粗糙度:各组治疗后粗糙度显著降低(P<0.05),单纯手工刮治组的粗糙度最低为(0.58±0.06),手工刮治辅以不同参数激光的粗糙度大于单纯手工刮治组而小于治疗前(P<0.05);相同照射时间,粗糙度200 mJ/P>160 mJ/P>120 mJ/P>80 mJ/P,但80 mJ/P、120 mJ/P、 160 mJ/P 3组差异不显著;相同脉冲能量,粗糙度60 s>30 s,差异显著(P<0.05)。根面形态:单纯手工刮治组的根面光滑但有玷污层,手工刮治辅以激光照射的根面表层消融,形成层状或颗粒状粗糙外观,随脉冲能量增大和照射时间延长,表层组织消融增多。结论:手工刮治、手工刮治辅以不同参数Er:YAG激光均可降低牙周病牙根面粗糙度;Er:YAG激光辅助照射通过清除根面玷污层,消融根面表层组织,形成粗糙表面;粗糙度与照射时间呈正相关;脉冲能量小于160 mJ/P时,增大脉冲能量对根面粗糙度无显著影响。[关键词] Er:YAG激光 根面形态 根面粗糙度     

脉冲Nd:YAG激光促进氟保护漆治疗牙齿敏感症临床观察

目的　观察脉冲Nd :YAG激光促进氟保护漆治疗牙齿敏感症的临床疗效。方法　用计算机程序控制脉冲Nd :YAG激光照射经涂一层氟保护漆的牙齿敏感症患牙 ,并分别与单纯涂一层氟保护漆或单纯脉冲Nd :YAG激光照射的疗效相比较。结果　涂氟保护漆加脉冲Nd :YAG激光照射治疗牙齿敏感症优于单纯涂保护漆或单纯脉冲Nd :YAG激光照射 ,疗效有显著性差异 (P <0 .0 5 )。结论　涂氟保护漆和脉冲Nd :YAG激光照射的联合应用是一种治疗牙齿敏感症较为有效的手段     

脉冲Nd:YAG激光与超声洁刮治联合治疗牙周炎的效果观察

目的　观察Nd:YAG激光与超声洁刮治联合治疗牙周炎的临床效果。方法　选择牙周袋4~7 mm的 26颗同颌对称同名的慢性牙周炎患牙,随机分为实验组(激光加洁刮治)和对照组(洁刮治)。比较两组患牙治疗前后牙周袋内细菌检出总数和主要细菌组成比。结果　实验组患牙激光照射后即刻,细菌检出总数较治疗前显著降低(P<0·05)。完成治疗后两组患牙牙周袋内细菌检出总数较治疗前显著降低(P<0·05);但两组间差异无显著性。两组患牙治疗后牙周袋内G+球菌升高、G-杆菌下降,与治疗前有显著性差异;治疗后1周实验组牙周袋内球杆菌比例与对照组比较差异有显著性。结论　参数为2 W、20 Hz、100 mJ的脉冲Nd:YAG激光牙周袋内照射可明显减少牙周袋内细菌总量;激光与超声洁刮治联合治疗能短期内显著改善龈下微生态环境。     

脉冲Nd:YAG激光根管内照射对狗牙尖周组织的影响

目的：观察脉冲Ｎｄ：ＹＡＧ激光根管内照射对狗牙尖周组织的影响。方法;组织学切片法和超薄切片法。结果;２．１Ｗ,１４０ｍＪ,１５Ｈｚ的脉冲;Ｎｄ：ＹＡＧ激光根管内照射２５ｓ,对尖周组织产生了明显的损伤,并延缓了尖周病变的愈合。１．２Ｗ,８０ｍＪ,１５Ｈｚ的脉冲Ｎｄ;ＹＡＧ激光根管内照射２５ｓ,对尖周组织产生的损伤明显轻于传统根管治疗,有利于尖周病变的愈合。     

Ex vivo study of the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG and Nd : YAG lasers

AIM: To evaluate the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG or Nd : YAG laser at various parameters. METHODOLOGY: Ninety maxillary canine teeth were sectioned transversely at the cemento-enamel junction and at the root tip to leave an 8-mm-long cylinder. The tooth specimen was centred in a metallic ring (16 mm diameter and 8 mm height) and embedded in acrylic resin. The root canals were prepared using a low-speed handpiece and a conical diamond bur, which was attached to a paralleling device. This bur was lowered to a depth previously determined by a silicone stop. Specimens were divided into nine groups: group I, dentine was treated with 2 mL of 17% EDTAC for 5 min. Groups II-V were irradiated with Er : YAG laser at the following parameters: group II - 8 Hz and 200 mJ input (120 mJ output); group III - 8 Hz and 400 mJ input (240 mJ output); group IV - 16 Hz and 200 mJ input (120 mJ output); group V - 16 Hz and 400 mJ input (240 mJ output). Groups VI-IX were irradiated with Nd : YAG laser at the following parameters: group VI - 10 Hz and 1 W input (0.4 W output); group VII - 10 Hz and 2 W input (0.8 W output); group VIII - 15 Hz and 1 W input (0.4 W output); group IX - 15 Hz and 2 W input (0.8 W output). The root canals were filled with an epoxy-based root canal sealer and submitted to a push-out test. RESULTS: Statistical analysis showed significant differences (P < 0.01) between Er : YAG and Nd : YAG laser treatments at the higher frequencies compared with 17% EDTAC. Greater adhesion values were obtained for groups IV and V (Er : YAG laser) and groups VIII and IX (Nd : YAG laser), which were statistically different from groups II and III (Er : YAG laser) and groups VI and VII (Nd : YAG laser). Treatment with only 17% EDTAC had the lowest adhesion values. CONCLUSIONS: An increase in frequency, independent of power settings, of the lasers used in this study increased adhesion of an epoxy-based root canal sealer.     

脉冲Nd：YAG激光照射对牙本质通透性的影响

本实验用不同能量参数的脉冲Ｎｄ：ＹＡＧ激光；分别照射牙本质窝洞底部，电镜观察和测定牙本质通透性，研究激光对牙本质的作用，初步探讨Ｎｄ：ＹＡＧ激光脱敏的机制。结果显示：０．６Ｗ（４０ｍＪ、１５Ｈｚ）组的牙本质通透性与对照组无统计学差异；０．９Ｗ（６０ｍＪ、１５Ｈｚ）和１．２Ｗ（８０ｍＪ，１５Ｈｚ）组的牙本质通透性明显增加。ＳＥＭ示所有激光组牙本质融熔、牙本质小管口模糊不清，洞底小管口部分被融熔物质阻塞。提示Ｎｄ：ＹＡＧ激光脱敏，可能存在其他的生物学脱敏机制。     

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??Objective     To investigate the effect of irradiation with Nd??YAG laser on the surface microstructure and temperature change of dental implants in vitro??in order to provide the reference for clinical parameter setting and operation method. Methods    The titanium discs were irradiated by Nd??YAG laser with different parameter setting. The surface microstructure was observed by scanning electron microscope?? and the temperature elevation was measured by thermocouple. The time to reach a 10?? increase in temperature was recorded as well. Results    ??1??Local areas with surface melting on 0.2W ??20 mJ??10 Hz??and significant melting with crackson 1W setting ??100 mJ??10 Hz or 50 mJ??20 Hz?? were observed after Nd??YAG laser irradiation without cooling??while the surface of the titanium disk is still molten with water vapor cooling.??2??The temperature elevation of titanium discs were less than 10?? with low power setting or water cooling conditions of Nd??YAG laser irradiation for 30 seconds. It took 13.8??6.2 and 7.8 seconds??respectively??to reach a 10?? increase threshold in temperature after being irradiated with 0.5 W ??50 mJ??10 Hz??and 1W??100 mJ??10 Hz or 50 mJ??20 Hz??without cooling conditions. Conclusion    Direct and prolonged exposure to Nd:YAG laser leads to microstructure change of implant surface??and may produce a risk of thermal damage to surrounding tissue. The reasonable parameter setting??mobile radiation mode and cooling are suggested.     

脉冲Nd:YAG激光影响复合树脂修补烤瓷粘接强度实验研究

目的：评价激光进行瓷面处理对复合树脂修补烤瓷的粘接效果。方法：分别用８％氢氟酸及３组能量参数的脉冲Ｎｄ：ＹＡＧ激光（１５Ｈｚ、４０ｍＪ、０．６Ｗ;１５Ｈｚ、６０ｍＪ、０．９Ｗ;１５Ｈｚ、８０ｍＪ、１．２Ｗ）对烤瓷牙粘接表面进行照射,照射时间均为１ｍｉｎ,涂硅烷液及活化剂后,粘接复合树脂。应用电子万能试验机测试复合树脂－烤瓷的抗剪切粘接强度。采用扫描电镜观察瓷处理面的形貌特征。结果：激光０．６Ｗ组、０．９Ｗ组、１．２Ｗ组及酸蚀组的抗剪切粘接强度分别为８．６１、１４．０７、１１．２２及１３．４７ＭＰａ,激光０．６Ｗ组明显低于酸蚀组,两者具有统计学差异,而０．９Ｗ组及１．２Ｗ组与酸蚀组则无显著性差异。扫描电镜显示经激光处理的瓷面粗糙不平,呈浅凹状及火山口状结构。结论：在适当能量参数下,脉冲Ｎｄ：ＹＡＧ激光可代替酸蚀进     

CO2, ER:YAG AND ND:YAG LASERS IN ENDODONTIC SURGERY

Objectives:

CO₂, Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software®) of 108 endodontically treated human permanent canines.

Material and methods:

Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO₂ laser (1 W, CW/CW); C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz); D: 90-degree apicoectomy with bur, and treatment of apical surface with CO₂ laser (1 W, CW/CW); E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz), root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz) and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz); G: apicoectomy with CO₂ laser (5W, CW/SP), root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO₂ laser (1 W, CW/CW); I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz).

Results:

Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%), B (17.24%) and F (17.84%).

Conclusions:

Groups B, C and F represent the best technical sequences to perform endodontic surgery.     

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.     

Temperature rise during Er:YAG and Nd:YAP laser ablation of dentin

This in vitro study compared temperature rises during cavity preparation with an Er:YAG laser, Nd:YAP laser, and a high-speed handpiece. Eighteen teeth were sectioned longitudinally and divided into six groups: group 1 was treated with a carbide bur on a high-speed dental handpiece; group 2 was treated with an Er:YAG laser with an energy of 140 mJ, a pulse repetition rate of 4 Hz; and group 3 was treated with an Nd:YAP laser with an energy of 240 mJ, a pulse repetition rate of 10 Hz. In these groups no water cooling was used. Groups 4 to 6 were treated in the same way, but with water spray. Temperature increases were measured at different dentin thicknesses by a microthermocouple attached to the inner side of the pulp chamber. Water cooling was essential to reduce temperature effects in all groups. Nd:YAP laser induced significantly higher temperature rises than Er:YAG or handpiece. Temperature response to the Er:YAG laser and the handpiece seemed to be similar.     

脉冲Nd:YAG激光辅助极固宁脱敏剂治疗老年牙本质过敏症的临床研究

目的：研究脉冲Nd：YAG激光辅助极固宁脱敏剂治疗老年牙本质过敏症的临床效果。方法：实验组用脉冲Nd：YAG激光1W（30mJ／cm^2、15Hz）照射120sec后，涂擦极固宁脱敏剂3次;对照组强采用极固宁脱敏剂3次。结果：实验组即刻、3个月及6个月有效率分别为87．29％、81．36％和75．42％，对照组的有效率为79．09％、63．64％和52．73％。即刻两组差异无屁著性（P〉0．05），而3个月、6个月差异有显著性（P〈0．01）。结论：脉冲Nd：YAG激光辅助极固宁脱敏荆治疗老年牙本质过敏症是一种高效、作用持久、使用安全的方法。     

Effects of Nd:YAG laser pulpotomy on human primary molars

The purpose of this study was to compare the effects of Nd:YAG laser pulpotomy to formocresol pulpotomy on human primary teeth. Patients with a primary tooth that required pulpotomy because of pulpal exposure to caries, were selected for this study. After removal of coronal pulpal tissue, Nd:YAG laser at 2 W, 20 Hz, 100 mJ or a 1:5 dilution of formocresol was introduced into the canal orifice for complete hemostasis. IRM paste was then placed over the pulp stump, and the tooth was restored either with composite resin or stainless steel crown. Sixty-eight teeth were treated with Nd:YAG laser and followed up for 6 to 64 months. Clinical success was achieved in 66 out of the 68 teeth (97 %), and 94.1 % were radiographically successful. In the control group, 69 primary molars were treated with formocresol and followed up for 9 to 66 months; 85.5 and 78.3% achieved clinical and radiographic success, respectively. The success rate of Nd:YAG laser pulpotomy was significantly higher than that of formocresol pulpotomy. The permanent successors of the laser-treated teeth erupted without any complications.