Effect of water aging on microtensile bond strength of dual-cured resin cements to pre-treated sintered zirconium-oxide ceramics

ObjectivesTo evaluate the hydrolytic stability of different dual-cure resin cements when luted to zirconia ceramic.MethodsEighteen cylinder-shaped zirconia blocks (Cercon Zirconia, Dentsply) were conditioned with: Group 1, no treatment; Group 2, sandblasting (125 μm alumina–Al₂O₃-particles); Group 3, tribochemical silica coating (50 μm silica-modified Al₂O₃ particles). Ceramic blocks were duplicated in composite resin (Tetric Evo Ceram, Ivoclar-Vivadent). Composite disks were luted to pre-treated ceramic surfaces using: (1) Clearfil Esthetic Cement (CEC; Kuraray); (2) Rely X Unicem (RXU; 3M ESPE); (3) Calibra (CAL; Dentsply Caulk). After 24 h, bonded samples were cut into microtensile sticks (1 mm²). Half of the sticks were loaded in tension until failure (cross-head speed of 0.5 mm/min). The remaining half was tested after 6 months of water storage at 37 °C. Data was analyzed with three-way ANOVA and Tukey’s test (P <0.05). Fractographic analysis was performed by SEM.ResultsAfter 24 h, bond strength of CEC to zirconia was significantly higher than that of RXU and CAL, independently from the ceramic pre-treatment (P <0.001). Using CAL, all samples failed prematurely except when luting to sandblasted surfaces. After 6 months of water aging, bond strength of CEC significantly decreased. RXU did not significantly alter bond strengths. Adhesion of sandblasted specimens luted with CAL fell over time. Micromorphological alterations were evident after water storage.SignificanceResin–ceramic interfacial longevity depended on cement selection rather than on surface pre-treatments. CEC and RXU were both suitable for luting zirconia. Water aging played an important role in the durability of zirconia-to-composite chemical bonds.     

氧化锆陶瓷与三种树脂粘接剂粘接剪切强度比较

目的探讨适合牙科氧化锆陶瓷的粘接材料。方法将烧结后的氧化锆陶瓷片分为3组,每组32片,分别采用三种自酸蚀粘接剂RelyX Unicem、PanaviaTM F、Superbond C﹠B与喷砂后的氧化锆陶瓷片粘接,水浴24h和水浴30d后,测试其粘接剪切强度。数据用SAS9.12软件进行统计学分析,粘接断面用扫描电镜观察。结果 PanaviaTMF树脂粘接材料粘接强度最好,分别为（31.36±3.49）MPa（水浴24h）、（29.52±3.44）MPa（水浴30d）。Superbond C﹠B能够取得较好的初期粘接强度（31.85±3.61）MPa（水浴24h）,但水浴30d后明显下降至（21.32±2.58）MPa,P〈0.05。RelyX Unicem的初期（水浴24h）粘接强度最小为（13.29±3.05）MPa,P〈0.0001,但水浴30d后粘接强度为（12.06±2.28）MPa,未见明显降低,P（0.05。结论含有MDP磷酸单体的树脂粘接材料可以使牙科氧化锆陶瓷获得最好的粘接效果。使用不含无机填料的化学固化型纯树脂粘接剂可以取得较好的初期粘接强度但长期效果欠佳。一步法自酸蚀树脂粘接剂虽然没有很高的初期粘接强度,但粘接效果尚能持久。     

Shear bond strength of composite resin cements to lithium disilicate ceramics

The aim of this study was to evaluate the shear bond strength of different commercial composite resin cement systems to lithium disilicate all-ceramic substrate. Five adhesive resin cement systems Panavia 21 and Panavia F (Kuraray), Variolink 2 (Ivoclar-Vivadent), RelyX Unicem Applicap and RelyX ARC (3M ESPE) were used on all-ceramic (IPS Empress 2; Ivoclar-Vivadent) substrate. Shear bond strength of adhesive resin cement to substrate was tested after thermocycling, or without thermocycling (n = 10). Substrate surfaces of the specimen after loading were SEM microscopically examined. The highest bond strengths in water stored conditions were obtained with RelyX ARC (28.7 +/-3.9 MPa), while in thermocycled conditions the highest bonding values were obtained with Variolink 2 (23.2 +/- 7.5 MPa). The lowest values in both water stored (5.8 +/- 4.0 MPa) and thermocycled (2.4 +/- 2.9 MPa) conditions were obtained with Panavia 21. Shear bond strengths appeared to be affected significantly by thermocycling (anova, P < 0.05). It was concluded that there were significant differences between the bond strengths of adhesive resin cements to lithium disilicate substrate.     

氧化物陶瓷与3种树脂水门汀初期粘接强度比较

目的:通过对2 种修复用氧化物陶瓷与3 种树脂水门汀的粘接抗剪强度比较,探讨适合牙科氧化物陶瓷的粘接材料.方法: 分别用3 种树脂水门汀Superbond C&B、RelyX~(TM)Unicem、Panavia~(TM) F与喷砂后的氧化锆(ZrO2)及三氧化二铝(Al_2O_3)陶瓷的粘接面粘接,37 ℃水浴24 h后测试其粘接抗剪强度,数据用SAS 9.12 软件进行统计学分析.结果: Al_2O_3陶瓷组间均有显著性差异(P<0.000 1), Superbond C&B粘接强度最高为(37.60±2.06) MPa. ZrO2陶瓷组中Superbond C&B与Panavia~(TM) F的粘接强度差异无显著性(P>0.05),RelyX~(TM)Unicem粘接强度最低为(13.29±3.05) MPa.结论: Superbond C&B、Panavia~(TM) F与氧化物陶瓷均具有较高的粘接强度,一步法自酸蚀粘接剂RelyX~(TM)Unicem虽然操作简便、提高了工作效率,但不如多步法系统获得的粘接强度大.     

Effect of thermocycling on the bond strength between dual-cured resin cements and zirconium-oxide ceramics

The present study evaluated the durability of bond strength between zirconia and 3 different resin cements. Thirty stabilized tetragonal zirconium-dioxide blocks were duplicated in dual-curing resin core build-up material specimens. Resin blocks were randomly luted to zirconium surfaces using 1) Clearfil Esthetic Cement (CLF), 2) RelyX Unicem Aplicap (RELX), or 3) Multilink Automix (MLA). After 24 h, half of the specimens from each of the 3 groups were loaded in tension until fracture (0.5 mm/min). The remaining half were tested after 6,000 thermal cycles (5 to 55°C). Data were analyzed using 2-way ANOVA and the Tukey test (α = 0.05). Fractographic analysis was performed using a stereomicroscope. Tensile bond strength values were significantly affected by the luting agent system employed and by thermal aging (P < 0.001). The highest tensile bond strength values in non-thermal-aged groups were observed for specimens from the RELX and CLF groups. In contrast, in the thermal-aged groups, the highest tensile bond strength values were for the MLA and RELX groups. Moreover, while thermocycling significantly affected bond strengths in the RELX and CLF groups, the mean strength of the MLA group did not significantly change after aging. There was little difference in the distribution of failure modes in any group.     

Determining efficacy of monitoring devices on ceramic bond to resin composite

Objectives: This paper aims to assess the effectiveness of 3D nanoroughness and 2D microroughness evaluations, by their correlation with contact angle measurements and shear bond strength test, in order to evaluate the effect of two different acids conditioning on the bonding efficacy of a leucite-based glass-ceramic to a composite resin. Study Design: Ceramic (IPS Empress) blocks were treated as follows: 1) no treatment, 2) 37% phosphoric acid (H3PO4), 15 s, 3) 9% hydrofluoric acid (HF), 5 min. Micro- and nano-roughness were assessed with a profilometer and by means of an atomic force microscopy (AFM). Water contact angle (CA) measurements were determined to assess wettability of the ceramic surfaces with the asixymetric drop shape analysis contact diameter technique. Shear bond strength (SBS) was tested to a resin composite (Z100) with three different adhesive systems (Scotchbond Multipurpose Plus, Clearfil New Bond, ProBOND). Scanning electron microscopy (SEM) images were performed. Results: Nanoroughness values assessed in 50x50 μm areas were higher for the HF group, these differences were not detected by profilometric analysis. HF treatment created the nano- roughest surfaces and the smallest CA (p<0.05), producing the highest SBS to the composite resin with all tested adhesive systems (p<0.05). No differences existed between the SBS produced by the adhesive systems evaluated with any of the surface treatments tested. Conclusions: Nano-roughness obtained in a 50x50 µm scan size areas was the most reliable data to evaluate the topographical changes produced by the different acid treatments on ceramic surfaces. Key words:Dental ceramic, acid etching, bonding efficacy, resin composite, adhesive systems, contact angle, roughness.     

4种黏结材料与氧化锆陶瓷黏结剪切强度的比较

目的:探讨适合牙科氧化锆陶瓷的黏结材料。方法:将烧结后的氧化锆陶瓷片分为4组,每组16片,分别采用RelyXTM ARC、PanaviaTM F、RelyXTM Luting、Fuji plus4种黏结材料与喷砂后的氧化锆陶瓷片黏结,水浴24h和水浴30d后,测试其黏结剪切强度,数据用SAS6.12软件进行统计学分析,黏结断面用扫描电镜观察。结果:PanaviaTMF树脂黏结材料黏结强度最好,分别为(34.7±3.44)MPa(水浴24h)、(31.5±3.44)MPa(水浴30d),与其他组黏结强度差别有统计学意义(P<0.01)。RelyXTM Luting,Fuji plus2种树脂改良型玻璃离子可以获得较好的初期(水浴24h)黏结强度,分别为(15.5±2.71)MPa和(16.0±1.77)MPa,但水浴30d后明显下降至(6.80±1.24)MPa和(3.38±2.32)MPa,P<0.05。结论:含有MDP磷酸单体的树脂黏结材料可以使牙科氧化锆陶瓷获得最好的黏结效果,使用树脂改良型玻璃离子可以产生较好的初期黏结强度,但黏结效果不能持久。     

Mechanical properties and bond strength of dual-cure resin composites to root canal dentin.

OBJECTIVES: To evaluate the regional mechanical properties of dual-cure resin composites and their regional bond strengths to root canal dentin. METHODS: One of the following dual-cure resin composites was placed in artificial post spaces: Unifil Core (UC), Clearfil DC Core (DC), Build-It FR (BI), Clearfil DC Core-automix (DCA), and photo-cured for 60s. After 24h storage, each specimen was serially sliced to harvest eight hour-glass shaped specimens for measurement of regional ultimate tensile strength (UTS), and the remaining eight semi-circular slabs were polished for the measurement of Knoop Hardness Number (KHN). For the microtensile bond strength (muTBS) test, post cavities were prepared in human premolar roots, and the cavity surfaces treated with Clearfil SE Bond and photo-cured for 10s. The post spaces were then filled with one of the above resin composites and photo-cured for 60s. After 24h storage, each specimen was serially sliced into 8, 0.6x0.6 mm-thick beams for the muTBS test. The data were divided into coronal and apical regions and analyzed using ANOVA and post hoc test (alpha=0.05). RESULTS: UTS and KHN were affected by the type of dual-cure resin composite and region (p<0.0001). There was no relationship between UTS and KHN for each material. The auto-mix type of resin composite possessed superior UTS to that of the hand-mix type. muTBS among the four composite materials were not significantly different at both apical and coronal regions (p>0.05). Regional differences in bond strengths were found for all materials (p<0.05). SIGNIFICANCE: The UTS and KHN of the dual-cure resin composites varied among each material, however, differences in the mechanical properties of the resin core materials did not affect their adhesion to root canal dentin.     

Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

Objective

The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs) and resin-modified glass ionomer cements (RMGICs).

Material and Methods

Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene''s tests and by two-way ANOVA and Tukey''s post hoc test at a significance level of 5%.

Results

Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post level did not influence the bond strength of fiber posts to root dentin (P=0.148). The major cause of failure was cohesive at the cement for all GICs and RMGICs.

Conclusions

Except for Ionoseal, all cements provided satisfactory bond strength values.     

Microtensile bond strength of a dual-cure resin core material to glass and quartz fibre posts

OBJECTIVES: To evaluate the microtensile bond strength (microTBS) of a dual-cure resin core material to different regions of fibre posts using different surface treatments. MATERIALS AND METHODS: Twenty-five silica zirconium glass fibre posts (Snowpost) and 25 quartz fibre posts (Aestheti-Plus) were used and randomly divided into five groups according to the surface treatments: (1) no surface treatment (Control) (2) dual-cure bonding agent, Clearfil Liner Bond 2V (LB) (3) LB followed by light curing for 20 s (LB and C) (4) silane coupling bonding agent agent, Clearfil Photobond with Porcelain Bond Activator (PB+PBA) (5) PB+PBA followed by light curing for 20 s (PB+PBA and LC). Treated posts were cemented into artificial post cavities using a dual-cure composite core material (Clearfil DC Core) and cured for 60 s from the top of the cavity. After 24 h storage in water, each specimen was serially sliced into 8, 0.6 x 0.6 mm2-thick beams for the microTBS test. The data were divided into three regions (upper/middle/bottom) and analyzed using three-way ANOVA and Dunnet's T3 multiple comparisons (alpha=0.05). RESULTS: There were no significant differences in bond strength between the three regions (p>0.05). The bond strengths were enhanced by the application of a silane coupling agent. For Snowpost, photoirradiation of the dual-cure bonding agent applied to the post surface significantly improved the bond strength (p<0.05) whereas it did not affect the bond strength of Aestheti-Plus post (p>0.05). CONCLUSION: The bond strength between fibre post and dual-cure resin core material depends upon the type of post and surface treatment. There were no regional differences in microTBS of the bonded post.     

填料含量对实验双固化树脂水门汀与纤维桩黏结强度的影响

目的:比较二氧化硅填料含量对EAM树脂材料黏结性能的影响,为研制纤维桩树脂核修复材料奠定基础.方法:根据二氧化硅填料在EAM树脂中添加含量的不同分为4组(A组:40%、B组:50%、C组:60%、D组:70%),E组(对照组)LuxaCore-Dual树脂,将各组树脂水门汀在圆筒形模具内分别与纤维桩黏结后,制备成微拉伸试件.用微拉伸试验机进行拉伸,直至试件破坏,并作统计学处理.结果:4个不同二氧化硅无机填料组的微拉伸强度分别为:A组(10.15±2.72)MPa,B组(11.48±2.81)MPa,C组(12.03±2.78)MPa,D组(10.07±2.06)MPa,E组(10.88±2.85)MPa,B、C两组的黏结强度显著高于A、D、E组(P<0.05).结论:60%左右无机填料含量的复合树脂微拉伸黏结强度较为理想.     

溶胶-凝胶法制备硅涂层提高牙科高强度陶瓷与复合树脂的粘接强度

目的:探讨溶胶-凝胶法在牙科高强度陶瓷表面改性对陶瓷和复合树脂粘接强度的影响。方法:喷砂玻璃氧化铝陶瓷和氧化锆陶瓷片各72片,每种陶瓷随机分为4组,每组18片,采取以下处理:A组,硅烷偶联剂;B组,20%硅溶胶涂层+硅烷偶联剂;C组,30%硅溶胶涂层+硅烷偶联剂;(D)40%硅溶胶涂层+硅烷偶联剂,制作陶瓷-复合树脂粘接体;每组样本再分为2个亚组,分别在37℃水浴中放置24 h和30 d后,测定陶瓷和树脂的剪切粘接强度。结果:2种陶瓷水浴24 h后,各涂层组粘接强度与单纯硅烷偶联剂组相比差异有统计学意义,其中30%硅溶胶处理组的粘接强度最高(P<0.05)。水浴30 d后,各组粘接强度均和水浴初期(24 h)相比差异无统计学意义,30%硅溶胶处理组的粘接强度最高(P<0.05)。结论:牙科氧化铝陶瓷和氧化锆陶瓷经过溶胶凝胶法纳米硅涂层表面改性结合硅烷偶联剂的处理可以显著提高陶瓷和树脂的粘接强度,并保持较好的粘接耐久性,30%硅溶胶提高粘接强度的效果最好。     

Micro-tensile bond testing of resin cements to dentin and an indirect resin composite.

OBJECTIVES: Micro-tensile bond strength (microTBS) evaluation and fractographic analysis were used to compare four resin cement systems (AC: All-Bond 2/Choice; RX: Single Bond/RelyX ARC; SB: Super-Bond C & B; and PF: Panavia F) in indirect composite/dentin adhesive joints. METHODS: Flat dentin surfaces were created on extracted human third molars. The resin cements were used according to the manufacturers' instructions for bonding silanized composite overlays to deep coronal dentin. 0.9x0.9 composite-dentin beams prepared from the luted specimens were stressed to failure in tension. Dentin sides of all fractured specimens were examined by scanning electron microscopy (SEM) to examine the failure modes. In group PF, morphologic features that could not be resolved at the SEM level were further validated by transmission electron microscopy (TEM) examination of the SEM specimens. RESULTS: Statistical analyses revealed significant difference (p<0.05) among microTBS and failure modes in the resin cement groups. The two groups (AC and RX) with highest microTBS failed predominantly along the composite overlay/cement interface. Cohesive failure in resin cement was primarily observed in group SB that exhibited intermediate microTBS values. In group PF with the lowest microTBS, failure occurred mostly along the dentin surface. Globular resin agglomerates seen by SEM on PF-treated dentin were distinguished from silica fillers by TEM. SIGNIFICANCE: The bond between the processed composite and the luting resin cement was the weak link in indirect composite restorations cemented with AC or RX. Super-Bond C&B exhibited intermediate tensile strength and Panavia F is less reliable when used in conjunction with a self-etching primer for bonding indirect restorations to dentin.     

Shear bond strength of resin cements to both ceramic and dentin

STATEMENT OF PROBLEM: All ceramic restorations benefit from resin cement bonding to the tooth. However, the literature is unclear on which cement, ceramic conditioning treatment, and dentin bonding agent produce the highest and longest-lasting bond strength. PURPOSE: This in vitro study evaluated immediate and 6-month shear bond strengths between a feldspathic ceramic and 4 different resin cements with the use of 6 different surface-conditioning treatments. Shear bond strengths between the 4 resin cements and dentin also were measured. MATERIAL AND METHODS: Four hundred eighty discs (10 mm in diameter and 4 mm thick) of Ceramco II porcelain were randomly divided into 6 main groups (n = 80). The ceramic specimens received 6 different surface conditioning treatments before the application of resin cement. These surface treatments were sanding with 600-grit silicon carbide paper, microetching with aluminum oxide, sanding followed by silane application, microetching followed by silane application, hydrofluoric acid-etching, and hydrofluoric acid-etching followed by silane application. Each group then was subdivided into 4 subgroups (n = 20) for the application of 1 of 4 cements: Nexus, Panavia 21, RelyX ARC, and Calibra. All cemented specimens were tested under shear loading until fracture on a universal testing machine; the load at fracture was reported in MPa as the bond strength. Bond strengths were determined at 24 hours and after 6 months of specimen storage in a saline solution. For dentin-resin cement shear bond strength testing, dentin specimens were treated with dentin bonding agents, and a thin layer of resin cement was applied according to the manufacturer's directions. Prodigy composite was bonded to the cement. Shear bond strengths were determined as above and reported in MPa at fracture. Data were analyzed with 3-way analysis of variance (P<.01). RESULTS: Hydrofluoric acid-etching followed by silane application produced bond strengths (15.0 +/- 7.4 to 21.8 +/- 5.8 MPa) in the highest statistical group with all 4 cements at both 24 hours and 6 months (P<.01). Sanding with 600-grit silicon carbide paper and microetching with aluminum oxide produced the lowest bond strengths (0.0 to 4.0 +/- 3.5 MPa). At 24 hours and 6 months, there were no significant differences among the 4 cements when hydrofluoric acid-etching was followed by silane application. Both auto- and light-polymerized dentin bonding agents bonded better to dentin than dual-polymerized bonding agents. CONCLUSION: Within the limitations of this study, hydrofluoric acid-etching followed by silane application produced the best bonds at 24 hours and 6 months with all 4 cements. Auto- and light-polymerized adhesives were associated with higher bond strengths to dentin than dual-polymerized adhesives.     

Human and bovine pulp-derived cell reactions to dental resin cements

Objectives

The objective of this study was to evaluate the cytotoxic reaction of transfected human pulp derived cells (tHPDC) and transfected bovine pulp derived cells (tBPDC) after exposure to resin cements [RelyX UnicemClicker (RX), MaxCem (MC), Panavia F 2.0 (PF), BisCem (BC), and Bistite II DC (BII)] and to compare it to the generation of reactive oxygen species (ROS).

Materials and methods

Set materials were extracted in culture medium, cell survival as a measure of cytotoxicity was determined photometrically using crystal violet after cells were exposed to the extracts for 24?h. The generation of ROS was detected by flow cytometry after cells were exposed to extract dilutions for 1?h.

Results

The ranking of the least to the most cytotoxic material was: RX < BII < PF < BC < MC for both cell lines, but for tHPDC, only MC and PF eluates were different from untreated controls. Generally, tBPDC were more susceptible to materials than tHPDC, but only for RX and BC was this difference statistically significant. All undiluted extracts increased ROS production in both cell lines but to a higher amount in tHPDC than in tBPDC.

Conclusions

tHPDC reacted less sensitive than tBPDC in the cytotoxicity test but with the same rank order of materials. In contrast, the cellular oxidative stress reaction was more pronounced in tHPDC than in tBPDC.

Clinical relevance

Depending on the residual dentine layer in deep cavities, biologically active resin monomers or additives released from resin cements may influence the dentine–pulp complex, for instance, its regenerative and reparative capacities.     

摩擦化学法硅涂层对氧化锆陶瓷粘接强度的影响

目的： 评估摩擦化学法硅涂层对氧化锆陶瓷粘接强度的影响。方法： 将切割烧结后的Lava氧化锆瓷块60件分为6组,每2组分别经喷砂/硅烷偶联剂、喷砂/CoJet Sand/硅烷偶联剂、无处理3种表面处理后,相同表面处理的2组中,每组分别用RelyX Unicem或Panavia F2.0与牙釉质粘接。各组随机抽取5件共30件进行24 h水浴,其余30件进行5000周水热循环,然后进行剪切粘接强度测试。采用SPSS 23.0软件包对数据进行双因素方差分析、Tukey HSD多重比较法及t检验。结果： 喷砂/CoJet/硅烷组的剪切强度均显著高于其他2组（P<0.001）;经老化试验后,喷砂/CoJet/硅烷组使用RelyX Unicem仍保持较高的剪切强度[(21.374±4.433)MPa],与其他各组相比有显著差异（P<0.001）。结论： 摩擦化学法硅涂层能够有效提高氧化锆的粘接强度及耐久性,表面处理方式与粘接剂之间的相互作用需得到临床关注。     

Effects of etching and adhesive applications on the bond strength between composite resin and glass-ionomer cements

Objective

This study determined the effects of various surface treatment modalities on the bond strength of composite resins to glass-ionomer cements.

Material and Methods

Conventional (Ketac^TM Molar Quick Applicap^TM) or resin-modified (Photac^TM Fil Quick Aplicap^TM) glass-ionomer cements were prepared. Two-step etch-rinse & bond adhesive (Adper^TM Single Bond 2) or single-step self-etching adhesive (Adper^TM Prompt^TM L-Pop^TM) was applied to the set cements. In the etch-rinse & bond group, the sample surfaces were pre-treated as follows: (1) no etching, (2) 15 s of etching with 35% phosphoric acid, (3) 30 s of etching, and (4) 60 s of etching. Following the placement of the composite resin (Filtek^TM Z250), the bond strength was measured in a universal testing machine and the data obtained were analyzed with the two-way analysis of variance (ANOVA) followed by the Tukey''s HSD post hoc analysis (p=0.05). Then, the fractured surfaces were examined by scanning electron microscopy.

Results

The bond strength of the composite resin to the conventional glass-ionomer cement was significantly lower than that to the resin-modified glass-ionomer cement (p<0.001). No significant differences were determined between the self-etching and etch-rinse & bond adhesives at any etching time (p>0.05). However, a greater bond strength was obtained with 30 s of phosphoric acid application.

Conclusions

The resin-modified glass-ionomer cement improved the bond strength of the composite resin to the glass-ionomer cement. Both etch-rinse & bond and self-etching adhesives may be used effectively in the lamination of glass-ionomer cements. However, an etching time of at least 30 s appears to be optimal.