The Journal of Adhesive Dentistry, 05/2011

Purpose: To evaluate the long-term outcome of all-ceramic resin-bonded fixed dental prostheses (RBFDPs) made with a two-retainer design or a cantilever single-retainer design. Materials and Methods: Overall, 38 anterior RBFDPs were made from a glass-infiltrated alumina ceramic (In-Ceram). Sixteen RBFDPs had a two-retainer design, while 22 RBFDPs had a cantilever single-retainer design. Phosphate monomer containing luting agents were used either after silica coating and silanation or after air-abrasion only. The mean observation time in the two-retainer group was 120.2 months and in the single-retainer group 111.1 months. Results: No restoration debonded. In the two-retainer group unilateral and bilateral fractures of the connectors occurred. In the case of unilateral fracture, the pontic remained in situ as a cantilever RBFDP for several years. In the single-retainer group, only one FDP fractured and was lost 48 months after insertion. The 10-year survival rate was 73.9% in the two-retainer group and 94.4% in the single-retainer group. When unilateral fracture of a FDP was taken as a criterion for failure, the 10-year survival rate decreased to 67.3% in the two-retainer group. Conclusion: Cantilever all-ceramic RBFDPs are an adequate alternative to two-retainer RBFDPs. Keywords: adhesive, all-ceramic restoration, alumina ceramic, cantilever fixed dental prosthesis, ceramic bonding, ceramic fracture, resin-bonded fixed dental prosthesis, survival rate

Purpose: To investigate the effect of Colloidal Platinum Nanoparticles (CPN) on the bond strength between dentin and 4-META/MMA-TBB resin using different concentrations of CPN. Materials and Methods: Twenty-five extracted human third molars were stored in 0.5% chloramine T. The occlusal dentin slices were prepared by grinding occlusal surfaces of each tooth and polishing with 600-grit silicon carbide paper under running water. One control and four experimental groups (2 specimens per group) were used as follows: a) dentin surfaces treated with 10-3 solution, followed by rinsing with water and subsequently an acrylic rod bonded with hand-mixed 4META/MMA-TBB resin (Super-Bond C&B, Sun Medical) (control); b) dentin surfaces treated with 10-3 etching solution, followed by rinsing with water and application of CPN (100% or 10%) as a primer solution for 60 s and rinsed with water for 20 s, then an acrylic rod bonded with Super-Bond C&B(Etch-CPN [100% or 10%]); c) dentin surfaces treated with CPN (100% or 10%) for 60 s, rinsed with water for 20 s, followed by application of 10-3 solution, then an acrylic rod bonded with Super-Bond C&B (CPN-Etch [100% or 10%]). After storage in 37°C water, specimens were sectioned into beams (cross-sectional area: 1 mm2) for microtensile bond strength testing at a crosshead speed of 1mm/min. The data were analyzed using the Games-Howell method (p 0.05; n = 15). Results: Etch-CPN (100), CPN-Etch(100) and CPN-Etch (10) showed significantly higher bond strengths compared to the control. When using 10% CPN, the highest bond strength was demonstrated. The bond strength of 4META/MMA-TBB resin was approximately doubled by CPN application. Conclusion: The results of this study showed that higher bond strengths are obtained when treating dentin with a lower concentration of CPN. Further evaluation to optimize conditions such as the application time and rinsing time are required. Keywords: dentin adhesion, nano-technology, microtensile bond strength, 4META/MMA-TBB resin

Purpose: To evaluate the association between the resin-dentin bond strength (microtensile bond strength, µTBS) and the physical properties (ultimate tensile strength [UTS] and microhardness [VHN]) of the cured adhesive resin using five commercial one-step self-etching systems. Materials and Methods: Futurabond NR, Go, G Bond, 1-step All Bond SE and Clearfil S3 Bond were applied on flat superficial dentin surfaces. Each adhesive system was applied in five teeth. A resin buildup was then made. After 24 h, resin-dentin beams (0.9 mm2) were prepared to be tested immediately at 0.5 mm/min. For the UTS measurement, hourglass specimens were prepared with each adhesive system (n = 5) to be tested under tensile stress at 0.5 mm/min. The fractured specimens from the UTS test were taken to a Vickers microhardness tester (25 gf/20 s). µTBS, UTS, and VHN values were submitted to a one-way ANOVA and Tukey's test (α = 0.05) for pairwise comparisons. Correlations between µTBS, UTS and VHN were analyzed using the Pearson product moment correlation test (α = 0.05). Results: Significantly higher µTBS values were observed for 1-step All Bond SE and Clearfil S3 Bond (p > 0.05). The adhesive All Bond SE showed the highest UTSmean among all systems (p 0.05). The adhesives All Bond SE and G-Bond showed the highest microhardness mean among all systems (p 0.05). A strong (r = 0.93) and significant (p = 0.021) correlation was only found between the µTBS and UTS values. Conclusion: The ultimate tensile strength of one-step self-etching systems correlates with the resin-dentin bond strength values. Keywords: resin-dentin bond strength, ultimate tensile strength, microhardness, adhesive systems, one-step self-etching, correlation

Purpose: To test the marginal adaptation of Class IV restorations made of different composite materials designed for anterior use. Materials and Methods: Forty-two extracted caries-free human maxillary central incisors were randomly divided into 7 experimental groups - one per composite tested - for which Class IV cavities were prepared. The microfilled composite materials tested (SolidBond/Durafill [D/SB], Syntac classic/Heliomolar [H/SC], Scotchbond1/ Experiment127 [EXI/SB1], Optibond FL/Point 4 [P4/OBFL], Prime&Bond NT/Esthet-X [EX/PBNT], ART Bond/ Miris [MIR/ART], SE Bond/Clearfil ST [CLE/SE-B]) were inserted in two increments after polymerization of their respective adhesive systems. While under simulated dentinal fluid pressure, specimens were submitted to cyclic incisal stress (1,200,000 cycles, maximum load 49 N) and thermal loading (3000 cycles). Both after polishing and after thermomechanical loading, impressions were made of the surface of each restoration, and epoxy replicas were prepared for the marginal adaptation evaluation using SEM. Results: Perfect margins before loading in enamel ranged from 49.9% (EXI/SB1) to 98.2% (MIR/ART) and after loading from 25.3% (EXI/SB1) to 91.9% (MIR/ART). For margins located in dentin, perfect margins ranged from 16.8% (EXI/SB1) to 100% (CLE/SE-B) before loading and from 4.6% (EXI/SB1) to 67.1% (CLE/SE-B) after loading. Conclusion: The poor results obtained in this in-vitro test with the microfilled composites suggest avoiding their use in large Class IV restorations with margins in dentin. Keywords: Class IV, marginal adaptation, adhesive restorations, SEM

Purpose: The aim of this study was to evaluate the influence of dentin abrasion on the microshear bond strength of two self-etching adhesive systems, using either an ultrasound diamond bur or a high-speed diamond bur. Materials and Methods: Twenty noncarious human third molars were sectioned mesiodistally into halves. The enamel was ground to expose a flat dentin surface on both sections. The dentinal surfaces were randomly assigned to two groups, depending on the method of smear layer preparation: ultrasound diamond bur (UB) or conventional diamond bur (CB). The prepared dentin surfaces received one of two self-etching systems: Clearfil SE Bond (CF) and One-Up Bond F (OB). A composite cylinder with a 0.95-mm diameter was bonded to each specimen and the microshear bond test was performed. The results were expressed in MPa and were subjected to two-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). Results: There was no significant difference in dentin bond strength when comparing the conventional and ultrasonic abrasion methods. When the adhesive systems were compared, Clearfil SE Bond achieved higher bond strength means than did One-Up Bond F. Conclusion: The dentin surface preparation method did not influence the microshear bond strength and the Clearfil SE Bond adhesive system, independent of bur type used, Clearfil SE Bond showed higher bond strengths than did the One-Up Bond F adhesive system. Keywords: microshear bond strength, self-etching adhesive systems, ultrasound, diamond bur

Purpose: Because studies have shown that adherence to dentin of resin-modified glass ionomers (RMGI) can be improved by surface treatment with a self-etching adhesive (SEA), the purpose of this in vitro study was to evaluate the water and saliva tolerance of this combination before and after application of SEA. Materials and Methods: Seventy cylinders of an RMGI (Fuji II LC) were bonded to the dentin of human teeth: 10 without any surface treatment, 10 after polyalkenoic acid conditioning, 10 after application of SEA, 10 after application of SEA on water contaminated dentin, 10 after application of SEA on saliva contaminated dentin, 10 on water contaminated light-cured SEA, and 10 on saliva contaminated light-cured SEA. The shear bond strength (SBS) was determined in a universal testing machine and the site of bond failure recorded. A Kruskal-Wallis test was performed followed by Games-Howell post-hoc pairwise comparison tests on the SBS results (p 0.05), and a chi-square test was used for the fractographic analysis (p 0.05). Results: The lowest SBS was obtained without conditioning (5 ± 1 MPa). Polyalkenoic acid improved SBS (8 ± 2 MPa) and SEA increased it very significantly (15 ± 2 MPa), even in the case of water contamination (16 ± 2 MPa before application of SEA, 21 ± 4 MPa after application of SEA), or saliva contamination (20 ± 7 MPa before application of SEA, 19 ± 6 MPa after application of SEA). The group bonded without conditioning resulted in only adhesive fractures, showing a statistically significant difference from the other groups. Conclusion: SEA in association with the Fuji II LC RMGI increased the SBS very significantly, even in the case of water or saliva contamination. Keywords: glass ionomer, self-etching adhesive, moisture, saliva contamination, shear bond strength

Purpose: To determine the adhesion of resin-modified glass-ionomer cement to bovine dentin under contaminated and decontaminated conditions. Materials and Methods: Forty-five bovine mandibular incisors were used. The surfaces of bovine dentin specimens were subjected to Temp-bond, dental handpiece lubricant (contamination), Hibiscrub, chlorhexidine or pumice (decontamination), as well as contamination followed by decontamination. From these, 14 test groups were created to investigate the effects of these variables on the microtensile bond strength of a resin-modified glassionomer cement to dentin. In addition, scanning electron microscopy was performed to examine the effects of contamination and decontamination procedures on the dentin surfaces. The data were analyzed by one-way ANOVA, Kruskal-Wallis, and Mann-Whitney tests. Results: SEM examination showed visible differences between the control group and dentin contaminated with Temp-bond or handpiece lubricant. All the contamination and decontamination test agents when used alone - except Hibiscrub - showed significant reductions in bond strength when compared to the control (p 0.001). All the test groups subjected to contamination followed by decontamination showed a significantly reduced bond strength (p 0.001) when compared to the control, with the exception of the handpiece lubricant/Hibiscrub combination. Conclusion: Under the conditions tested, Temp-bond, handpiece lubricant, chlorhexidine, and pumice may have an adverse effect on the bonding of resin-modified glass ionomer to dentin. Hibiscrub was effective in decontaminating handpiece lubricant but not Temp-bond. Keywords: dentin bonding, microtensile bond strength, contamination, decontamination

Purpose: To investigate regional shear bond strength to lateral walls of ceramic inlays in occlusal and occlusoproximal cavities using etch-and-rinse and self-adhesive resin cements and a glass-ionomer luting agent. Materials and Methods: IPS e.max Press ceramic inlays were made in 50 Class I and 50 Class II standardized cavities in intact extracted human molars and divided into 5 luting agent subgroups (n = 10): Variolink II (VL); Multilink Sprint (MLS); Multilink Automix (MLA); RelyX Unicem (RLX), and Ketac Cem Aplicap (KC). Inlays were pre-etched with IPS Ceramic etching gel for 60s. After 48 h, two disks of ca 1.0 mm thickness, one of superficial and the other of deep dentin, were push-out tested in a universal testing machine at a crosshead speed of 1.0 mm/min. The mode of failure was determined under a stereomicroscope at 20X. Data were analyzed with oneway ANOVA, and Scheffé's test was used for post-hoc comparisons (α = 0.05). Results: There were no significant differences in shear bond strength between Class I and Class II cavities for the dual-curing system in light-curing mode (VL=MLS=RLX), except that RLX demonstrated greater bond strength to deep dentin in Class II cavities. Bond strength values were significantly higher on deep than on superficial dentin. KC showed the worst result. Failures were mixed (adhesive/cohesive) for the resin luting cements and solely adhesive (cement/ceramic) for the glass-ionomer luting agent. Conclusion: Dual-curing etch-and-rinse or self-etching self-adhesive resin luting cements achieved greater bond strength when light curing was applied, with no differences between Class I and Class II cavities but higher values for deep vs superficial dentin. The weakest adhesion was obtained with glass-ionomer luting agent in both cavity types. Keywords: ceramic inlays, push-out, bond strength, etch-and-rinse, self-etching, resin cement

Purpose: To examine the availability of sol-gel processed silica coating for alumina-based ceramic bonding, and determine which silica sol concentration was appropriate for silica coating. Materials and Methods: Sixty disks of In-Ceram alumina ceramic were fabricated and randomly divided into 5 main groups. The disks received 5 different surface conditioning treatments: Group Al, sandblasted; Group AlC, sandblasted + silane coupling agent applied; Groups Al20C, Al30C, and Al40C, sandblasted, silica coating via sol-gel process prepared using 20 wt%, 30 wt%, and 40 wt% silica sols, and then silane coupling agent applied. Before bonding, one-step adhesives were applied on pre-prepared ceramic surfaces of all groups. Then, 60 dentin specimens were prepared and conditioned with phosphoric acid and one-step adhesive. Ceramic disks of all groups were cemented to dentin specimens with dual-curing resin cements. Fracture strength was determined at 24 h and after 20 days of storage in water. Results: Groups Al20C, Al30C, and Al40C revealed significantly higher fracture strength than groups Al and AlC. No statistically significant difference in fracture strength was found between groups Al and AlC, or among groups Al20C, Al30C, and Al40C. Fracture strength values of all the groups did not change after 20 days of water storage. Conclusion: Sol-gel processed silica coating can enhance fracture strength of In-Ceram alumina ceramic after bonding to dentin, and different silica sol concentrations produced the same effects. Twenty days of water storage did not decrease the fracture strength. Keywords: ceramic, alumina, sol-gel, dental bonding, silica coating, fracture strength

Purpose: To evaluate the influence of four surface treatments on the bond strength of a self-adhesive resin cement to an yttria-stabilized zirconia (Y-TZP) ceramic material (Lava Frame zirconia). Materials and Methods: Forty plates (8 x 6 x 1 mm) of a Y-TZP ceramic restorative material were randomly assigned to four groups (n = 10) according to the surface treatments: control, no treatment; airborne-particle abrasion with 50-µm Al2O3; coating with an MDP-based primer; conditioning with Rocatec System. The ceramic plates treated with each of the four methods were further divided into 2 subgroups according to the resin cement tested: RelyXTM ARC (ARC, conventional) and RelyXTM Unicem (Ucem, self-adhesive). The resin cements were put into PVC tubes (diameter 0.75 mm, 0.5 mm height) placed on the ceramic plate surfaces. After water storage at 37°C for 24 h, the specimens were submitted to a microshear bond strength (µSBS) test at a crosshead speed of 1.0 mm/min. Results: The surface treatments significantly influenced the µSBS (p 0.05). For the four surface treatments, UCem presented significantly higher µSBS than ARC (p 0.05). For both resin cements, the best result was produced by the MDP-based primer: ARC 15.9 ± 5.0 MPa and UCem 36.2 ± 2.1 MPa. The highest µSBS values were presented by UCem on ceramic plates treated with the MDP-based primer (36.2 ± 2.1 MPa) and Rocatec system (37.4 ± 2.3 MPa). Conclusion: Irrespective of the surface treatment, the self-adhesive resin cement performed better in terms of bond strength to yttria-stabilized zirconia ceramic than did conventional resin cement. Keywords: yttria-stabilized zirconia ceramic, microshear bond strength, surface treatment, resin cements, SEM, EDS

Purpose: To determine the effect of resin surface treatment with dissolved maleic anhydride in butanone added into primer on the tensile bond strength between an acrylic denture base resin and a silicone soft liner. Materials and Methods: To test tensile bond strength, standard dumbbell-shaped acrylic specimens were prepared. Five experimental groups, including the control, were tested (n = 5). Maleic anhydride solutions prepared in butanone at concentrations of 1%, 5%, 10% or 20% were then mixed with 1 ml of Primo adhesive and the mixtures were applied onto the resin bonding surfaces. Silicone liner material was applied to resin surfaces in the conventional manner. Tensile bond strength of the specimens was measured in a universal testing machine. Fractured surfaces were observed under the scanning electron microscope, and resulting chemical changes with the solutions used were analyzed spectroscopically. Results: The highest bond strength value was obtained for the group treated with 5% maleic anhydride (2.53 ± 0.48 MPa); the lowest value was for the group treated with 20% maleic anhydride (1.59 ± 0.29 MPa). Mixed failure was the dominant type seen in the experimental groups. Spectroscopic analysis showed the interaction of the anhydride carbonyl groups with the Primo primer. Conclusion: The treatment of resin surfaces with maleic anhydride added to Primo adhesive effectively increased bond strength between silicone soft liner and denture base resin. Keywords: PMMA, silicone soft liner, tensile bonding, SEM, FTIR, maleic anhydride

Purpose: The aim of this clinical study was to investigate the influence of salivary exposure on microtensile bond strength of one self-etching adhesive resin. Materials and Methods: Thirty carious premolars were divided into two groups: a rubber-dam was either inserted before or after cavity preparation and the cavities were restored using direct composite resin. After extraction, the teeth were sectioned into microbars and the microtensile bond strength (MTBS) test was conducted (a = 0.05). Scanning electron microscopy (SEM) and silver nitrate staining to detect nanoleakage were conducted to evaluate the sealing quality of the bonded interface. Results: Statistical analysis revealed that placement of rubber-dam before cavity preparation resulted in significantly higher MTBS values (24 ± 2 MPa) and predominantly cohesive failures (85%). SEM of specimens exposed to saliva revealed the presence of structural defects at the tooth/resin interface and pull-out of shorter resin tags. Silver nitrate nanoleakage confirmed these findings as well. Conclusion: It is recommended to insert a rubber-dam before commencing with cavity preparation in order to ensure strong and durable bond strength. Keywords: salivary contamination, microtensile bond strength, SEM