Kr:F准分子激光对釉质表面粘结强度的影响

目的 :探讨在粘接技术中应用Kr:F准分子激光的可能性。方法 :经Kr:F激光照射和酸蚀后的牙齿釉质面 ,分别与窝沟封闭剂粘接 ,比较两组的粘接强度。结果 :Kr:F激光处理组与酸蚀组粘接强度无显著性差异 (p >0 0 5 )。结论 :Kr:F准分子激光可替代化学酸蚀法处理釉质表面 ,并具有操作简便、抗酸力增强等独特的优越性     

Kr:F准分子激光作用釉质所产生的形态学变化

目的 :探讨Kr :F激光对牙釉质作用的机制及合适的能量参数。方法 :扫描电镜 (SEM)观察六种不同能量密度的Kr:F激光照射釉质表面产生的形态学变化。结果 :Kr:F准分子激光对釉质产生切割作用。随着能量密度的增加 ,由酸蚀状改变到产生光洁熔融的表面。结论 :Kr:F激光产生的不同釉质形态学变化 ,在牙科学领域有着良好的应用前景。     

Nd：YAG牙科激光刻蚀釉质和磷酸酸蚀釉质后粘接强度之比较

本文比较了Ｎｄ：ＹＡＧ牙科激光刻蚀釉质和常规磷酸酸蚀釉质后粘接强度的变化，发现常规酸蚀组的粘接强度高于激光照射３０ｍＪ－１０ｐｐｓ和８０ｍＪ－１０ｐｐｓ组，激光处理的二组间粘接强度无明显差异，另外，酸蚀剂的剂型对粘接强度无明显影响。     

局部应用氟化物对酸蚀釉质作用的体外研究

目的：评价局部应用氟化物对酸蚀釉质的作用。方法：收集正畸减数拔除的年轻前磨牙40个，制备釉质样本，随机分成对照组，lg／L氟化钠液组，含氟牙膏组，联合应用组。用饮料对釉质间断性酸蚀1周，然后使用不同的氟化物处理酸蚀的釉质表面1周。采用显微硬度计检测釉质表面显微硬度值（SMH），原子力显微镜（AFM）、扫描电镜（SEM）观察牙体硬组织表面的结构。结果：饮料浸泡后釉质的SMH明显下降。与对照组相比，氟化物处理后各氟化物处理组的釉质SMH均有明显增加（P＜0．001）。AFM和SEM均可见酸蚀后的釉质表面呈典型的蜂窝状结构，SEM观察显示氟化物处理后，各组釉质表面均有一定沉积物。结论：饮料会导致体外釉质表面的脱矿，氟化物能够促进体外酸蚀釉质的再矿化。     

不同酸蚀条件对釉质表面的影响研究

目的　探究不同pH值的盐酸溶液和酸蚀时间对釉质表面的影响。方法　制作40个釉质片样本，每个样本表面分为未处理面和处理面。根据处理面酸蚀条件分为8组，其中酸蚀时间为30 s，pH值分别为1.6、2.4、3.2、4.0的4组记为A1、A2、A3、A4组；酸蚀时间为60 s，pH值分别为1.6、2.4、3.2、4.0的4组记为B1、B2、B3、B4组。利用显微硬度计测量样本表面显微硬度；激光共聚焦显微镜测量样本未处理面和处理面之间形成的高度差（即釉质丧失量）。对结果进行两因素析因设计资料的方差分析。结果　酸蚀后，A1～A4组样本表面显微硬度值分别下降（42.1 ± 5.8）、（23.6 ± 5.7）、（10.9 ± 6.9）和（-0.6 ± 2.6）MPa；B1～B4组样本表面显微硬度值分别下降（59.3 ± 6.6）、（35.4 ± 9.2）、（15.7 ± 5.1）和（7.7 ± 3.1）MPa。A1～A4组样本未处理面和处理面之间的高度差分别为（793.4 ± 43.0）、（319.2 ± 20.4）、（15.8 ± 2.4）和（-1.4 ± 3.3）nm；B1～B4组样本未处理面和处理面之间的高度差分别为（1366.6 ± 174.8）、（437.2 ± 41.0）、（75.1 ± 6.4）和（1.3 ± 3.2）nm。方差分析结果显示，酸蚀时间和盐酸溶液的pH值对釉质表面显微硬度值下降量及釉质丧失量均有显著影响。结论　酸蚀时间和盐酸溶液的pH值均是影响釉质表面显微硬度值下降量及釉质丧失量的因素，且酸蚀时间和盐酸溶液的pH值对釉质丧失量的影响存在交互作用。     

正畸不同用氟方法预防釉质粘接面早期龋的超微结构观察

目的;测定应用氟化物的不同方法对釉质吸收氟离子的影响。方法：采用因固定正畸需要而拔除的双尖牙１２颗,随机分成对照组,酸蚀中用氟组和酸蚀后用氟组,每组牙釉质经酸蚀和不同用氟方法处理后,做扫描电镜检查。结果;酸蚀后用氟组釉质表面的反应产物最多,釉质吸收的氟离子最多。     

Longhurst釉质微打磨后漂白牙釉质表面形态的扫描电镜观察

目的：观察牙齿Longhurst法釉质微打磨以及与家庭漂白联合应用后釉质表面形态的变化。方法：24个离体牙随机分为3组,组为对照组,B组采用Longhurst釉质微打磨,即35%磷酸酸蚀,然后钨钢车针打磨,组采用ACLonghurst法打磨后家庭漂白4周,通过扫描电镜观察釉质表面形态的变化。结果：Longhurst法釉质微打磨后牙釉质表层釉柱结构消失,继续漂白4周,釉质不规则孔隙增多。结论：Longhurst是釉质表面的机械磨除,而随后的漂白可造成釉质的脱矿表现。     

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1牙体粘接修复术1.1定义借助于牙体硬组织表面处理,使材料与牙体粘接的方法。1.2牙釉质的粘接目前对釉质的粘接主要采用酸蚀技术,即通过酸蚀刻釉质表层,获得树脂修复体的微机械固位,从而增强复合树脂与釉质的粘接强度。     

Er,Cr:YSGG激光照射对窝沟封闭剂粘结性的影响

目的 :探讨Er,Cr:YSGG激光照射作为窝沟封闭前釉质预处理方式的可能性。方法 :以 40颗离体前磨牙做为标本 ,随机分成 4组 ,唇面釉质分别采用下列方式处理 ,A组 :杯状刷处理 酸蚀 ,B组 :钻切割 酸蚀。C组 :Er ,Cr :YSGG激光照射 ,D组 :Er,Cr :YSGG激光照射 酸蚀。测试窝沟封闭剂与釉质面的抗剪强度 ,并用扫描电镜观察 4种方式处理后釉质表面的形态特征。结果 :Er ,Cr :YSGG激光照射与传统杯状刷或钻处理后酸蚀的釉质面抗剪强度相似无显著性差异 (P >0 .0 5 ) ,Er ,Cr:YSGG激光照射后酸蚀也不增大抗剪强度。SEM观察Er ,Cr :YSGG激光照射后的釉质面不规则 ,鱼鳞状 ,无玷污层。结论 :Er ,Cr :YSGG激光照射可代替传统杯状刷或钻处理后酸蚀 ,是一种较好的窝沟封闭前预处理方式     

酸蚀与未酸蚀对金属托槽再次粘接效果的影响

目的:探讨金属托槽脱落后重粘接前釉质表面的处理方法以及重粘接的时间.方法:60 颗离体牙随机分成未酸蚀组和酸蚀组,分别在即刻、24 h内、4 d进行托槽重粘接,24 h后托槽粘接强度达最大时进行抗剪强度测试,记录粘接材料残余指数. 结果:即刻、24 h内托槽重粘接酸蚀组、未酸蚀组之间无显著性差异,而4 d托槽重粘接酸蚀组、未酸蚀组之间有显著性差异,酸蚀组中4 d托槽重粘接抗剪强度最大.结论:即刻、24 h内托槽重粘接不需要酸蚀,4 d及4 d后粘接需要酸蚀;建议托槽脱落后尽早重粘接.     

Bond strengths of orthodontic bracket after acid-etched, Er:YAG laser-irradiated and combined treatment on enamel surface

Laser ablation has been proposed as an alternative method to acid etching: however, previous studies have obtained contrasting results. The purpose of this study was to compare the bond strengths after acid etching, laser ablation, acid etching followed by laser ablation, and laser ablation followed by acid etching. Forty specimens were randomly assigned to one of the four groups. Two more specimens in each group did not undergo bond test and were prepared for observation with scanning electron microscope (SEM) after the four kinds of surface treatment. After the bond test, all specimens were inspected under the digital stereomicroscope and SEM to record the bond failure mode. Student's t-test results showed that the mean bond strength (13.0 +/- 2.4 N) of the laser group was not significantly different from that of the acid-etched group (11.8 +/- 1.8 N) (P > .05). However, this strength was significantly higher than that of the acid-etched then laser-ablated group (10.4 +/- 1.4 N) or that of the laser-ablated then acid-etched group (9.1 +/- 1.8 N). The failure modes occurred predominantly at the bracket-resin interface. Er:YAG laser ablation consumed less time compared with the acid-etching technique. Therefore, Er:YAG laser ablation can be an alternative tool to conventional acid etching.     

Effectiveness of an Er:YAG laser in etching the enamel surface for orthodontic bracket retention

The purpose of this study was to test the effectiveness of an Er:YAG laser in etching the enamel surface for orthodontic treatment. Bovine incisors were either acid-etched or laser-treated. An orthodontic bracket was attached on each treated surface using one-step dentin adhesive and self-curing resin. Tensile bond strength was then evaluated. In addition, the surface morphology of specimens treated with phosphoric acid/laser and self-etching primer, as well as the cross-section of enamel-primer-resin interfaces, were observed. One-Up Bond F-treated specimens after Er:YAG laser ablation showed statistically similar tensile bond strength (9.9 +/- 1.3 MPa) to that of phosphoric acid-etched specimens (11.8 +/- 1.7 MPa). Surface roughness and thickness of the enamel-primer-resin interfaces did not much affect the tensile bond strength of the tested specimens. In conclusion, Er:YAG laser ablation achieved clinically acceptable level of tensile bond strength when used with One-Up Bond F.     

Er:YAG激光照射对牙本质粘结强度的影响

目的探讨Er:YAG激光照射对牙本质粘结强度的影响。方法选取离体磨牙或前磨牙40颗,随机分为4组:A:酸蚀(35%磷酸)组;B:Er:YAG激光组;C:Er:YAG激光+磷酸酸蚀组;D:空白对照组。每组随机选取2颗制备成3 mm厚的牙本质盘,相应预处理后扫描电镜观察;每组剩余8颗牙制备统一标准粘结面,相应预处理后与树脂粘结测量剪切粘结强度。结果扫描电镜结果显示牙本质面经相应预处理后发生明显改变;统计分析结果显示A组剪切粘结强度最大(16.03±6.56)MPa,其次为C组(13.21±6.08)MPa,两组间差异无统计学意义(P>0.05);D组剪切粘结强度最低(4.52±1.02)MPa,与B组(7.91±4.56)MPa比较差异无统计学意义(P>0.05),与A、C组比较差异有统计学意义(P<0.05)。结论 Er:YAG激光照射联合磷酸酸蚀较单纯Er:YAG激光照射可提高牙本质剪切粘结强度。     

Er:YAG激光预备对牙釉质表面性能及树脂粘结强度的影响

目的:探讨Er:YAG激光预备对牙釉质表面性能及树脂粘结强度的影响。方法:选取50颗无龋坏、无充填物的人离体前磨牙或磨牙,用涡轮手机按近远中方向将离体牙切割成颊/舌两部分,最终选取84个样件,按不同的表面处理方法随机分为7组(A-G组),每组12个样件。每组2个样件扫描电镜观察,其余10个样件分别在处理后的牙釉质表面粘结光固化复合树脂,进行剪切强度测试。结果:A组剪切强度最高(20.51±3.33) MPa。B、C、D组剪切强度次之,与A组比差异无统计学意义。E、F、G组剪切强度较弱,其中E组剪切强度与B、C、D组无显著差异,F、G组与其他组有显著差异。扫描电镜观察:随着激光能量的增加,牙釉质表面粗糙度增加。激光处理后再进行酸蚀处理,牙釉质表面整体结构均匀,釉柱结构清晰可见,无玷污层。结论:Er:YAG激光处理牙釉质表面不能达到类似酸蚀的效果。激光加酸蚀能达到类似酸蚀的效果。牙釉质剪切粘结强度随着激光能量的增加而增加。[关键词] Er:YAG激光 酸蚀 牙釉质 剪切粘结强度     

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     

Etching enamel for orthodontics with an erbium, chromium:yttrium-scandium-gallium-garnet laser system

OBJECTIVE: To test the shear bond strength, surface characteristics, and fracture mode of brackets that are bonded to enamel etched with an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser operated at different power outputs: 0.5 W, 1 W, and 2 W. MATERIALS AND METHODS: Human premolars that had been extracted for orthodontic purposes were used. Enamel was etched with an Er,Cr:YSGG laser system operated at one of three power outputs or with orthophosphoric acid. RESULTS: The shear bond strength associated with the 0.5-W laser irradiation was significantly less than the strengths obtained with the other irradiations. Both the 1-W and 2-W laser irradiations were capable of etching enamel in the same manner. This finding was confirmed by scanning electron microscopy examination. The evaluation of adhesive-remnant-index scores demonstrated no statistically significant difference in bond failure site among the groups, except for the 0.5-W laser-etched group. Generally, more adhesive was left on the enamel surface with laser irradiation than with acid etching. CONCLUSION: The mean shear bond strength and enamel surface etching obtained with an Er,Cr: YSGG laser (operated at 1 W or 2 W for 15 seconds) is comparable to that obtained with acid etching.     

Comparative evaluation of surface topography of tooth prepared using erbium,chromium: Yttrium,scandium, gallium,garnet laser and bur and its clinical implications

Background:

Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique.

Materials and Methods:

Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3–0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine.

Results:

The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer.Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength.

Conclusions:

Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.Key Words: Acid etching, bond strength, erbium, chromium: Yttrium, scandium, gallium, garnet laser, laser etching, scanning electron microscope     

Enamel demineralization and bracket bond strength when etching with acid and /or Er:YAG laser

Background:  Enamel etching for brackets is usually done with phosphoric acid. Er:YAG lasers have been recently used for this purpose with conflicting results. The effects of lasers on tooth demineralization and the effects of different combinations of laser treatments and bonding agents were evaluated in this study. Methods:  The enamel contents of fluorine, calcium oxide and phosphorus pentoxide (P₂O₅) were analysed using acid etching, laser treatment or both. The tensile bond strength of metallic and ceramic brackets using Transbond^® XT and Fuji Ortho^® LC were also tested, using acid etching, laser treatment or a combination of both. Results:  All treatments reduced the contents of fluorine, P₂O₅ and calcium oxide, and acid reduced P₂O₅ levels more than laser. The bond strength with laser was weaker than with acid, and stronger when combining both. When using laser, the best adhesive was the Fuji Ortho^® LC. The combination of laser and acid produced the best results when using Transbond^® XT. Conclusions:  The demineralization promoted by laser was lower than the one produced with acid. Laser treatment produced lower tensile stress strength than acid, but still enough to produce clinically efficient retention. The combination of laser and acid produced the best retention results.     

A comparative evaluation of shear bond strength of porcelain and composite using different bonding agents — An in vitro study

Objective

The purpose of the present in vitro study is to compare and evaluate the shear bond strength of porcelain and composite using different bonding agents.

Materials and methods

Sixty-three porcelain pellets were prepared and were divided into 9 groups. Three surface treatment and two bonding agents were evaluated. The surface treatment were: 1) sandblasting; 2) etching with 35% phosphoric acid; and 3) etching with 8% hydrofluoric acid. Applying bonding agents Scotch bond adhesive and clearfil liner bond 2V and combination of these treatments. Composite resin was condensed and light cured for 60 seconds on the porcelain specimens which were stored in distilled water at 37°C for 24 hours before mechanical testing.

Results

The bond strength were significantly different according to ANOVA F-test (F = 6.28, p < 0.01) and Duncan’s Multiple Range Test. Eight percent hydrofluoric acid showed higher bond strength when compared to 35% phosphoric acid etching and sandblasting by 50 micron aluminum oxide. Highest bond strength was observed with hydrofluoric acid + clearfil.

Conclusion

Etching with 8% hydrofluoric acid + clearfil liner bond showed higher bond strength when compared to hydrofluoric acid alone. This is indicative that effect of silane and etching can be use to improve mechanico chemical bonding. Among bonding agents used clearfil liner showed higher bond strength when compared to scotch bond adhesive.