3种粘接剂分别粘接金属托槽至抛光及上釉锆瓷的粘接强度

目的:研究3种粘接剂对抛光及上釉锆瓷与正畸金属托槽粘接强度和耐久性的影响。方法:选用2种通用型粘接剂Single Bond Universal(SBU)和Prime&Bond Universal(PBU),以Transbond^TM MIP(TM)为对照分别将抛光组、上釉组锆瓷与上颌中切牙金属托槽粘接,试样共6组(n=20)。水浴或水浴+冷热循环储存后测试全部试件剪切粘接强度(SBS),分析断裂形态以及粘接剂残留指数(ARI)。结果:粘接剂(P<0.001)和储存条件(P<0.001)显著影响锆瓷与托槽的剪切粘接强度;抛光或上釉(P=0.09)组间无统计学差异。SBU在各组中都表现出较强的粘接强度和较低的ARI,3种粘接剂间的ARI分数存在显著差异(P<0.001)。结论:粘接金属托槽与抛光及上釉锆瓷时,SBU较PBU和TM有更好的粘接性能。     

人工唾液条件下3种自酸蚀粘接剂与牙本质粘接耐久性研究

目的　探讨Single bond™ Universal等3种不同类型自酸蚀粘接剂与牙本质的粘接强度和耐久性。方法　选取 2016年5—7月解放军总医院口腔颌面外科拔除的24颗新鲜人离体第三磨牙,随机分为3组,每组8颗,分别选用Clearfil SE Bond（SE组）、G-Bond plus（GBp组）、Single bond™ Universal（SBU组）等3种自酸蚀粘接剂与新鲜牙本质粘接并制备试件。每组挑选出完整试件160个,再分为两个亚组（各80个试件）,分别在即刻与人工唾液浸泡6个月后行微拉伸粘接强度实验,体视显微镜下观察试件断裂类型。 结果　SE组、GBp组、SBU组即刻牙本质粘接强度分别为（55.70 ± 11.07）、（52.85 ± 7.54）和（62.82 ± 8.70）MPa,其中SBU组高于SE组和GBp组,差异有统计学意义（P < 0.05）。人工唾液保存6个月后,SE组、GBp组、SBU组牙本质粘接强度分别为（13.51 ± 4.99）、（43.53 ± 6.82）和（49.13 ± 6.58）MPa,3组之间差异均有统计学意义（P < 0.05）。6个月时粘接界面观察,SE组断裂模式均为粘接界面断裂;GBp组16个试件为牙本质内聚断裂,4个试件为复合树脂内聚断裂;SBU组28个试件为牙本质内聚断裂,8个试件为复合树脂内聚断裂。 结论　Single bond™ Universal即刻牙本质粘接强度和人工唾液老化后6个月粘接强度均显著高于Clearfil SE Bond、G-Bond plus;Single bond™ Universal粘接强度大,稳定耐久,可提供良好的粘接效果。     

不同浓度单宁酸在不同酸蚀模式下对通用型粘接剂粘接强度的影响

目的研究不同浓度单宁酸在全酸蚀与自酸蚀条件对通用型粘接剂在牙本质表面粘接强度的影响。 方法将60颗无龋离体人磨牙置于存储盒中随机盲取分成2组（全酸蚀A组与自酸蚀B组,n = 30）,再将每组随机分为5个亚组（n = 6）。在使用通用型粘接剂Single Bond Universal（SBU）前,在牙本质面分别涂抹浓度为0%（对照组）、25%、50%、75%和100%的单宁酸3 min并冲洗吹干。实验试件在37 ℃水中保存24 h后进行微拉伸强度测试（μTBSt）。使用Two-Way ANOVA与Games-Howell对数据进行统计学分析。用体式显微镜观察断裂面模式并在扫描电镜（SEM）下观察微拉伸试件的牙本质断端。 结果在全酸蚀模式下,75%单宁酸组粘接强度[（34.51 ± 8.43）MPa]与100%单宁酸组粘接强度[（36.16 ± 5.20）MPa]显著高于其他各组（F = 32.301,P<0.001）;在自酸蚀模式下,25%单宁酸[（31.06 ± 3.41）MPa]可显著提升SBU与牙本质粘接强度（F = 23.570,P<0.001）。双因素分析结果证实,单宁酸浓度（F = 23.134,P<0.001）与酸蚀模式（F = 4.465,P = 0.036）对粘接强度具有显著影响且两要素间显著相关（F = 28.231,P<0.001）。断裂模式分析与电镜观察结果表明,在牙本质表面不同酸蚀模式与不同浓度单宁酸所形成的界面形态差异显著。 结论在不同酸蚀模式下,不同浓度的单宁酸均可显著改善SBU与牙本质的粘接强度。     

通用型粘接剂和树脂水门汀对氧化锆剪切粘接强度的影响

目的 研究通用型粘接剂和树脂水门汀对氧化锆陶瓷剪切粘接强度和耐久性的影响。方法 氧化锆陶瓷烧结制作20 mm×10 mm×10 mm和10 mm×10 mm×10mm两种尺寸的试件,实验分为12组,将这2种试件分别采用不同的树脂水门汀（RelyX Ultimate树脂水门汀、Clearfil SAC自粘接树脂水门汀）和通用粘接剂（无粘接剂、Scotchbond通用粘接剂、Clearfil SE One粘接剂）在不同的储存条件（水浴、水浴+冷热循环）下进行粘接。测试剪切粘接强度,分析断裂形态。结果 水门汀（F=8.41,P<0.01）和粘接剂（F=30.34,P<0.01）对氧化锆剪切粘接强度的影响有统计学意义;储存条件对剪切粘接强度的影响无统计学意义（F=1.83,P=0.18）。RelyX Ultimate树脂水门汀、无粘接剂、水浴+冷热循环储存时的剪切粘接强度最低（14.02 MPa±6.86 MPa）,RelyX Ultimate树脂水门汀、Scotchbond通用粘接剂、水浴+冷热循环储存时的剪切粘接强度最高（54.12 MPa±8.37 MPa）。结论 通用型粘接剂可提高树脂水门汀对氧化锆的粘接耐久性。非自粘接的树脂水门汀如不使用通用型粘接剂则其粘接耐久性下降。     

通用型粘接剂和树脂水门汀对氧化锆 剪切粘接强度的影响

目的 研究通用型粘接剂和树脂水门汀对氧化锆陶瓷剪切粘接强度和耐久性的影响。方法 氧化锆陶瓷烧结制作20 mm×10 mm×10 mm和10 mm×10 mm×10mm两种尺寸的试件,实验分为12组,将这2种试件分别采用不同的树脂水门汀（RelyX Ultimate树脂水门汀、Clearfil SAC自粘接树脂水门汀）和通用粘接剂（无粘接剂、Scotchbond通用粘接剂、Clearfil SE One粘接剂）在不同的储存条件（水浴、水浴+冷热循环）下进行粘接。测试剪切粘接强度,分析断裂形态。结果 水门汀（F=8.41,P<0.01）和粘接剂（F=30.34,P<0.01）对氧化锆剪切粘接强度的影响有统计学意义;储存条件对剪切粘接强度的影响无统计学意义（F=1.83,P=0.18）。RelyX Ultimate树脂水门汀、无粘接剂、水浴+冷热循环储存时的剪切粘接强度最低（14.02 MPa±6.86 MPa）,RelyX Ultimate树脂水门汀、Scotchbond通用粘接剂、水浴+冷热循环储存时的剪切粘接强度最高（54.12 MPa±8.37 MPa）。结论 通用型粘接剂可提高树脂水门汀对氧化锆的粘接耐久性。非自粘接的树脂水门汀如不使用通用型粘接剂则其粘接耐久性下降。     

POSS纳米填料对复合树脂与牙本质粘接强度的影响

目的：评价自制POSS纳米填料复合树脂经冷热循环后粘接强度的变化,为新型树脂的研发和应用提供参考依据。方法：160颗人类离体前磨牙随机分为5组,牙体近中面牙本质预备后选用Prime＆BondNT粘接剂分别粘接5种复合树脂（自制POSS纳米复合树脂、未添加POSS填料复合树脂、FiltekTMZ250、FiltekTMZ350、DU-RAFILLVS）。80个试件经10000次冷热循环后,万能材料试验机测试所有试件粘接强度。结果：冷热循环前后粘接强度测试结果分别为：POSS纳米树脂组（27.84±2.19,27.01±2.19）MPa,无POSS填料树脂组（26.73±3.37,20.28±3.30）MPa,FiltekTMZ250（27.56±1.95,26.77±2.74）MPa,FiltekTMZ350（27.68±2.28,24.47±3.04）MPa,DURAFILL○RVS（27.40±1.83,21.49±2.92）MPa。冷热循环前五组树脂粘接强度差异无显著性,经冷热循环各组材料粘接强度差异有显著性（P〈0.05）。结论：5种复合树脂牙本质粘接强度差异显著,添入POSS纳米树脂组冷热循环前后粘接强度均优于未添入组,其耐温度老化性能优于部分临床常用复合树脂。     

不同表面处理对LAVA树脂纳米瓷剪切强度的影响

目的 研究不同处理方式对树脂纳米瓷(LAVA Ultimate)与树脂水门汀粘接后剪切强度的影响。方法 本次实验分为喷砂实验和粘接实验两部分。将LAVA Ultimate切削成大小约 6 mm×6 mm,高度约为2 mm的样本80片,依照不同的喷砂时间和喷砂气压随机分为4组,每组10个试件,使用3M Single Bond Universal+3M RelyX Ultimate与纳米树脂柱粘接后在万能试验机上测试断裂载荷,计算剪切强度,选出最高组。同等喷砂条件下40个样本随机分为A(Single Bond Universal(3M)+RelyX Ultimate(3M)) ,B (Porcelain Primer(Bisco)+ All-bond Universal(Bisco)+RelyX Ultimate(3M))与纳米树脂柱进行粘接。粘接后再分成两个亚组,分别进行冷热循环5 000次和恒温水浴24 h。在万能试验机上测试断裂载荷,计算剪切强度,采用单因素方差分析对数据进行统计分析。结果 单因素方差分析结果表明不同喷砂条件的分组对剪切强度差异有统计学意义(第2组和第4组)(P=0.037);冷热循环后,A组和B组试件的剪切强度均有明显下降(P=0.003,P<0.01);A、B组不同粘接方式的剪切强度差异无统计学意义(P=0.062,P=0.671)。结论 0.2 MPa压力下喷砂14 s可明显提高树脂纳米瓷与树脂水门汀的剪切强度;冷热循环会明显降低剪切强度;粘接方式对剪切强度无明显影响。     

3种粘接材料与氧化锆陶瓷粘接抗剪切强度的比较

目的研究3种粘接材料与氧化锆陶瓷材料的初期及耐久粘接抗剪切强度。方法将预烧结氧化锆陶瓷片试件喷砂后分为3组,每组20个,分别采用玻璃离子水门汀(GIC组)、Panavia F 2.0树脂粘接剂(PF组)、Clearfil SA Luting树脂粘接剂(SAC组)与核树脂块粘接,每组随机选取10个试件进行冷热循环实验(10 000次,5～55℃),用计算机控制万能材料试验机测定其粘接抗剪切强度。结果未经冷热循环处理的GIC组、PF组、SAC组试件的粘接抗剪切强度值分别为(21.98±1.78)MPa、(30.26±1.73)MPa、(28.63±2.02)MPa,GIC组试件的粘接抗剪切强度低于其他两组(P<0.01),PF组与SAC组的试件相比差异无统计学意义(P>0.05);而冷热循环后,GIC组、PF组、SAC组试件的粘接抗剪切强度值分别为(10.72±2.03)MPa、(28.50±1.54)MPa、(27.02±1.79)MPa,GIC组试件经冷热循环后,其粘接抗剪切强度值明显下降(P<0.05),而其他两组试件经冷热循环后其粘接抗剪切强度值无明显改变(P>0.05)。结论使用玻璃离子可获得较好的初期粘接抗剪切强度,但耐久粘接强度欠佳;含磷酸酯单体的树脂粘接剂可使氧化锆陶瓷获得良好的初期粘接抗剪切强度及耐久粘接抗剪切强度;自粘接型树脂粘接剂操作简便,粘接抗剪切强度与自酸蚀型树脂粘接剂相当,且粘接效果持久。     

3种树脂粘接水门汀与铸造纯钛粘接强度研究

目的：研究3种复合树脂粘固剂与铸造纯钛的粘接强度。方法：用牙科铸钛的方法制作直径分别为4mm和5mm的钛棒,切割成长度为4mm的小钛片。2种规格的钛片配对粘接面用400～1200目碳化硅砂纸在流水下打磨抛光,使之呈均匀一致的平面。50μm氧化铝喷砂,另一组表面不喷砂作为对照,分别使用Super-BondC＆B、Panavia F、Rely X Unicem 3种复合树脂粘固剂粘接。扫描电镜观察喷砂前后铸造纯钛的表面形态。复合树脂粘接剂固化后经37℃恒温水浴24h以及5000次5～55℃冷热循环,测试剪切强度。用SAS的ANOVA过程对各组数据进行分析。结果：喷砂前后纯钛与Panavia F的剪切强度最高,分别为（26.62±3.40）MPa、（23.71±5.28）MPa;5000次冷热循环后,喷砂组的铸造纯钛与Panavia F的剪切强度最高（27.12±8.68）MPa;未喷砂的铸造纯钛与Super-Bond C＆B、Rely X Unicem的粘接强度最低,并且有12.5%的脱落率。结论：本实验结果表明喷砂可以提高Super-Bond C＆B、Panavia F、Rely X Unicem的粘结力和粘结耐久力。不喷砂时,Panavia F与铸造纯钛之间能获得较高的粘接强度和良好的粘接耐久性,喷砂以后优势不再明显。     

氯已定预处理对两步法自酸蚀粘接剂牙本质粘接界面稳定性的影响

目的：探讨氯已定预处理对两步法自酸蚀粘接剂的牙本质粘接界面稳定性的影响.方法：40颗离体人磨牙沿垂直于牙长轴的方向切割,暴露冠中部牙本质作为粘接面,牙本质试件随机分为两组,一组在粘接处理前涂布0.2％氯已定为实验组,一组无预处理为对照组,两组经两步法自酸蚀粘接剂SE Bond处理后,堆积复合树脂制备成粘接试件.每组随机抽取2个试件借助微拉曼光谱仪分析粘接剂的双键转化率,剩余的18个试件随机分为两个亚组,分别于即刻和冷热循环5000次后检测微拉伸粘接强度和界面的纳米渗漏情况.结果：0.2％氯已定预处理对SE Bond的树脂双键转化率无显著性影响（P＞0.05）.即刻测试时,对照组和实验组间的微拉伸粘接强度和纳米渗漏差异无统计学意义（PP ＞0.05）.冷热循环老化处理后,实验组的微拉伸粘接强度显著高于对照组,纳米渗漏程度显著低于对照组（P＜0.05）.结论：0.2％氯已定预处理不会干扰SE Bond的树脂聚合,且可提高其与牙本质粘接界面的稳定性.     

树脂水门汀与氧化锆陶瓷剪切粘接强度的研究

目的评估不同实验条件下树脂水门汀与氧化锆瓷之间的剪切粘接强度（SBS）。 方法使用计算机辅助设计与制作（CAD/CAM）设备切割并烧结制作6个边长为2 cm的正方体氧化锆试件。按不同实验条件将8种双固化树脂水门汀分为13组（n = 20）：（1）Monobond N + Multilink N（MMN组）;（2）Ivoclean + Monobond N + Multilink N（IMM组）;（3）Ivoclean + Monobond N + Multilink N[无喷砂,IMM（ns）组];（4）Tetric N-Bond Universal + Multilink Speed（TUM组）;（5）Multilink Speed（MLS组）;（6）Z-Prime Plus + TheraCem（ZPT组）;（7）Z-Prime Plus + Duo-Link（ZPD组）;（8）Single Bond Universal + RelyX U200（SRU组）;（9）RelyX U200（RXU组）;（10）Single Bond Universal + RelyX Ultimate Clicker（SRU组）;（11）OptiBond Versa + Kerr NX3（OVK组）;（12）Clearfil Universal Bond + Clearfil SAC（CUS组）;（13）Clearfil SAC（SAC组）。将每组树脂水门汀自混合注入透明模具并将其无压力置于氧化锆面后进行光照固化。所有试件在37 ℃水中存储24 h后进行SBS测试。采用SPSS 19.0软件One-Way ANOVA（P<0.05）对SBS进行统计学分析。利用电子体视显微镜观察氧化锆端断裂界面。 结果本实验中13组树脂水门汀的SBS（单位：MPa）降序排列依次为：OVK（27.51 ± 3.65）>IMM（27.28 ± 3.79）>SRC（26.77 ± 3.62）>CUS（25.36 ± 3.10）>TUM（25.22 ± 4.88）>ZPD（23.96 ± 6.25）>MLS（23.13 ± 2.74）>MMN（23.07 ± 3.71）>SAC（22.20 ± 3.59）>IMM（ns）（21.99 ± 3.50）>SRU（19.19 ± 2.27）>ZPT（18.62 ± 2.08）>RXU（15.04 ± 4.02）。 结论（1）不同树脂水门汀的SBS具有材料依赖性;（2）在氧化锆表面进行喷砂处理、使用专用清洗剂或将通用型粘接剂作为底漆使用有利于提高树脂水门汀的SBS。     

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??Objective    To study the effect of different surface treatment for hybrid ceramic on bonding strength of adhesive resin. Methods    The Vita Enamic block was cut by CAD/CAM. The specimens??36 pieces??size??10 mm × 10 mm ×3 mm??were randomly divided into six groups??6 pieces per group????control group??sandblasting group??etching group??silane group??etching+silane group and sandblasting+silane group. The adhesive area was circle of radius 2 mm??on the center of surface treated. The adhesive resin??EmbracTM??dual cure??was placed on the adhesive area??up to height 4 mm. The bonding strength of each group was detected by the universal material testing machine after 24 h of  adhesive resin cure. Results    The bonding strength was as follows at the speed of 0.5 mm/min??control group??6.2199 ± 0.9662??MPa??sandblasting group??8.3043 ± 1.2074??MPa??etching group??7.2266 ± 1.1112??MPa??silane group??15.0703 ± 1.1033??MPa??etching+sliane group??9.6446 ± 1.1725??MPa and sandblasting+silane group??13.1765 ± 2.312??MPa. Statistical analysis was performed using AVOVA. There was singnificant difference in the bonding strength between each group??except between etching and sandlasting group??etching and control group??P < 0.05??. Conclusion    The surface of hybride ceramic treated by sandblasting??etching and silane??alone or combined??can enhance the bonding strength of adhesive resin. The result of sandblasting group is better than etching group??and the silane is the best among them for the bonding strength of  adhesive resin with hybrid ceramic.     

Effects of surface treatments on bond strength of glass-infiltrated ceramic

The purpose of this study was to evaluate the effects of various surface treatments on the bond strength at the In-Ceram/resin composite interface. Ninety-eight In-Ceram specimens were divided into seven groups and exposed to various surface treatments as follows: (A) control (B) saliva contamination (C) saliva contamination plus aluminum oxide sandblasting (D) glove powder contamination (E) glove powder contamination plus aluminum oxide sandblasting (F) rough aluminum oxide sandblasting and (G) excess glass infiltration. A resin composite cylinder was cemented to each In-Ceram specimen with Panavia 21 resin luting cement. Half of the cemented specimens in each group were stored in water for 24 h, and the other half were stored in water for 2 weeks and then were thermo-cycled for 2000 cycles. Shear bond strengths (SBS) of seven specimens in each subgroup were determined and analysed using analysis of variance (ANOVA) and Tukey HSD test as well as Student's t-test. Scanning electronic microscopy was used to identify the type of bond failure. Shear bond strength was significantly decreased by saliva and glove powder contaminations (P < 0.05). Sandblasting treatment did not improve the saliva-contaminated specimens. However, the glove powder plus sandblasting group showed no significant difference in SBS compared with the control group. There was no significant difference in SBS between the excess glass-infiltrating group and the control group. The SBS was significantly decreased by rough aluminum oxide sandblasting (P < 0.05). The SBS values of groups without thermocycling were significantly greater than those of groups with thermocycling (P < 0.05). There were no significant differences among SBS values of the seven groups with thermocycling. Combined cohesive and adhesive bond failures were seen in every group. Various surface treatments or contaminants may significantly influence the bond strength of In-Ceram restorative in clinical use.     

Bonding interface and dentin enzymatic activity of two universal adhesives applied following different etching approaches

ObjectivesEtching approaches [37% phosphoric acid, self-etching, 10–3 solution (3% ferric chloride dissolved in 10% citric acid), or 1.4% nitric acid] were evaluated regarding enamel shear bond strength (24 h), dentin microtensile bond strength (24 h and 2 years), failure mode, enzymatic activity of the hybrid layer, and nanoleakage (24 h and 2 years) of Prime&Bond Universal (PBU, Dentsply-Sirona) and Gluma Bond Universal (GBU, Kulzer).MethodsAdhesives were applied on blot-dried (wet-bonding, positive control) or air-dried (remaining groups) dentin after acid-etching (15 s) or in self-etch mode. Enamel and dentin bond strength tests used 160 human teeth (n = 10). Failure mode of tested samples and nanoleakage within the dentin-adhesive interface (n = 5) were analyzed by scanning electron microscopy. Dentin enzymatic activity was investigated by in situ zymography (n = 3).ResultsEnamel bond strengths did not differ statistically among groups. Wet-bonding with 37% phosphoric acid showed similar dentin bond strength compared to 10–3 solution or 1.4% nitric acid at 24 h for both adhesives. None of the etchants inhibited enzymatic activity, and all groups showed dentin bond strength reduction after 2-year storage. GBU showed higher nanoleakage. Experimental etchants did not affect enamel bond strength. Dentin bond strength was not stable after 2 years, despite promising 24-hour results.SignificanceThis study suggests multiple etching approaches to optimize and achieve stable dentin bonding, while also offering in-depth information about the performance of recently released universal adhesive systems.     

不同表面处理方法在纳米混合树脂复合材料修复中的应用

目的： 分析不同表面处理方法和粘接剂自酸蚀功能单体对树脂-复合材料界面即时修复粘结强度和完整性的影响。方法： 采用纳米树脂复合材料制作98个树脂复合材料,随机分为A1、A2、B1、B2、C、D组,各14个试件。表面未处理的试件作为阳性对照组（14个试件）。A1组用Gluma 通用粘接剂系统抛光,A2组用Gluma 通用粘接剂系统抛光、喷砂,B1组用Tokuyama Bond ForceⅡ^TM粘结系统抛光,B2组用Tokuyama Bond ForceⅡ^TM抛光、喷砂,C组仅经抛光样品组。D组仅做喷砂。采用与底物相同的树脂复合材料,对修复后试件进行剪切粘结强度（shear bond strength,SBS）测试,所有样本均进行电子显微镜扫描、测定表面轮廓,进行失效分析。采用SPSS 20.0软件包对数据进行统计学处理。结果： D组修复粘结强度显著高于阴性对照组（P<0.05）,A1、A2、B2、B1组粘结强度显著高于C、D组（P<0.05）;B1、D或A1组相比,粘结强度无显著差异（P>0.05）;B2组、阳性对照组粘结强度无显著差异（P>0.05）。除喷砂、TBFⅡ外,阳性对照组粘合强度值显著高于A1、C组（P<0.05）。抛光后表面粘合失效率高于喷砂样本（P<0.05）;抛光、Gluma处理样品粘合失败率高于抛光、TBFⅡ处理样品（P<0.05）;喷砂、TBFⅡ处理的表面内聚破坏率高于抛光、TBFⅡ处理（P<0.05）。抛光技术的表面粗糙度与喷砂技术相比,较规则且粗糙度较低（P<0.05）。结论： 经喷砂处理的复合材料基材加TBFⅡ,其修复粘结性最强,且表面内聚破坏率较高,TBFⅡ处理粘合失败率低。但经喷砂处理后的材料易堆积食物残渣,而抛光后的材料则不易发生。使用喷砂处理的复合材料基材上加TBFⅡ的患者,需正确有效地维护口腔卫生。     

Influence of application method on surface free‐energy and bond strength of universal adhesive systems to enamel

The aim of the present study was to determine the influence of different adhesive application methods and etching modes on enamel bond effectiveness of universal adhesives using shear bond strength (SBS) testing and surface free‐energy (SFE) measurements. The adhesives Scotchbond Universal, All‐Bond Universal, Adhese Universal, and G‐Premio Bond were used. Prepared bovine enamel specimens were divided into four groups, based on type of adhesive, and subjected to the following surface treatments: (i) total‐etch mode with active application; (ii) total‐etch mode with inactive application; (iii) self‐etch mode with active application; and (iv) self‐etch mode with inactive application. Bonded specimens were subjected to SBS testing. The SFE of the enamel surfaces with adhesive was measured after rinsing with acetone and water. The SBS values in total‐etch mode were significantly higher than those in self‐etch mode. In total‐etch mode, significantly lower SBS values were observed with active application compared with inactive application; in contrast, in self‐etch mode there were no significant differences in SBS between active and inactive applications. A reduction in total SFE was observed for active application compared with inactive application. The interaction between etching mode and application method was statistically significant, and the application method significantly affected enamel bond strength in total‐etch mode.     

The effect of nonvital bleaching on the shear bond strength of composite resin using three adhesive systems

PURPOSE: To evaluate the effect of nonvital bleaching on the shear bond strength of composite resin using three adhesive systems. MATERIALS AND METHODS: Two hundred seventy bovine teeth were assigned to 3 groups (n = 90): SP, paste of sodium perborate and water; CP, 37% carbamide peroxide; CO, control group (no treatment). After the bleaching treatment, the teeth in each group were cut into enamel (E) and dentin (D) sections. The teeth were embedded in polyester resin and polished in order to obtain a flat E or D surface. Each group was divided into 6 subgroups (n = 15) according to substrate (E and D) and adhesive system: SB, Single Bond (solvent: water/alcohol); PB, Prime & Bond NT (solvent: acetone); CLF, Clearfil SE Bond (solvent: water). The adhesive system was applied on each flat surface according to the manufacturer's instructions and a cylinder of composite resin Z-250 was overlaid. The specimens were stored in distilled water for 7 days at 37 degrees C. The SBS test was performed in a universal testing machine with crosshead speed of 0.5 mm/min. The data obtained (in MPa) were statistically analyzed with two-way ANOVA and Tukey's test (p < or = 0.05). RESULTS: The bleaching treatment influenced the SBS, regardless of the adhesive system used. On enamel, the SP and CP bleaching treatments reduced the SBS values. On dentin, the SP bleaching agent reduced the SBS values, but the CP bleaching did not. CONCLUSION: Nonvital bleaching treatment with sodium perborate may adversely affect shear bond strength of composite resin for both enamel and dentin. Similar effects can be expected from 37% carbamide peroxide bleaching agent on enamel but not dentin bonding strength. The use of water/alcohol and acetone-based adhesive systems cannot reverse the effects of bleaching treatments on bond strengths.     

Effects of a torsion load on the shear bond strength with different bonding techniques

The purpose of this study was to test the hypothesis that a torsional load applied after bracket bonding does not affect the shear bond strength (SBS) with different bonding techniques. Sixty human premolars were divided into two groups (experimental and control) to investigate the effects of a torsion load, and the two groups were further subdivided into three groups of 10 for the evaluation of different adhesive systems (one etch-and-rinse adhesive, Transbond XT; two self-etching primer adhesives, Transbond Plus and Beauty Ortho Bond). A torsion load (1.45 N/cm) was applied by beta-titanium wire at 15 minutes after bracket bonding in the experimental groups. All specimens were then thermocycled between 5 and 55°C for approximately 1 week (6000 cycles). The SBS for each sample was examined with a universal testing machine and the adhesive remnant index (ARI) score was calculated. Data were compared by two-way analysis of variance, Student's t-test, and a chi-square test. The SBS for Transbond XT after thermocycling with a torsion load was significantly lower than that without a torsion load. For Transbond Plus and Beauty Ortho Bond, there was no significant difference in the mean SBS between specimens thermocycled with and without a torsion load. No significant difference in the distribution of frequencies among the ARI categories was observed among the six groups, although the ARI scores for specimens with a torsion load tended to be higher than those without a torsion load. In conclusion, the SBS of the conventional etch-and-rinse adhesive system significantly decreased under a torsion load with thermocycling.     

Effect of interchanging two composite resin system with a dentine adhesive

There is a tendency to interchange dentine adhesives and composite resins when using composite resins for restorations. This study used marginal contraction gaps to test the effect of changing composite resins with a dentine adhesive. Cylindrical butt-joint cavities were prepared entirely in dentine using extracted human teeth. Two groups of control cavities (30 cavities per group) were restored with Prisma-Bond/Prisma-Fil and Heliobond/Heliomolar respectively. Two groups of test cavities (30 cavities per group) were restored using the dentine adhesive. Prisma Universal Bond with Prisma-Fil on one group and Prisma Universal Bond and Heliomolar in the other. Following thermocycling the marginal contraction gaps were measured and assessed. The results showed a significant reduction in marginal contraction gaps when using either composite resin with Prisma Universal Bond. This indicates a compatibility of both resins with the adhesive in this instance.     

Shear Bond Strength of Dicor Using Resin Adhesive Systems and Light Activated Cement

A laboratory study was conducted to determine the shear bond strength to dentin of etched and silane-treated Dicor castable ceramic glass using a resin cement and newer generation adhesive systems. scanning electron microscopy (SEW examinations were also completed to evaluate the failure sites. The mean shear bond strength of the control (resin cement only, no adhesive system) was 2.1 ± 1.2 MPa. The shear bond strength values determjned for the adhesive systems and resin cement are as follows: Prisma Universal Bond 2, 18.7 ± 2.9; XR Primer/XR Bond, 16.9 ± 6.4: Scotchbond 2, 15.8 ± 6.2; Tenure Solution. 15.4 ± 4.5; and Gluma, 14.8 ± 5.5 MPa. SEM examinations of the debonded specimens attached with prisms Universal Bond 2 and Tenure Solution showed a complex failure pattern with cohesive failure in the glass ceramic material and adhesive failure between the resin cement and the etched and silane-treated glass surface. The debonding pattern of specimens attached with XR Primer/XR Bond. Scotchbond 2 and Gluma were primarily adhesive between the dentin and resin materials. The results of thfs study support the use of an adhesive system in conjunction with a resin cement for placement of Dim castable ceramic restorations.