The Journal of Adhesive Dentistry, 06/2006

Purpose: To examine the effects of the hemostatic agents ViscoStat and ViscoStat Plus on the shear bond strength (SBS) of composite resin (CR) to dentin in the presence and absence of blood. Materials and Methods: Sixty permanent teeth mounted in acrylic were randomly divided into 5 groups (n = 12): (1) control, C; (2) ViscoStat, VS; (3) ViscoStat Plus, VS+; (4) ViscoStat and blood, VS/B; (5) ViscoStat Plus and blood, VS+/B. Groups 2 and 3 were exposed to VS and VS+, respectively. Freshly drawn human blood was placed on groups 4 and 5 immediately followed by VS and VS+, respectively. Specimens remained undisturbed for 1 min and were rinsed with tap water for 1 min. All groups were etched with 35% phosphoric acid and were bonded utilizing the Ultradent bonding clamp, Optibond Solo Plus, and Z-250 composite resin. Following water storage for 48 hrs at 37°C, specimens were debonded in an Instron test frame at a crosshead speed of 0.5 mm/min. Statistical analysis was done with one-way analysis of variance. Results: The mean SBS ± SD in MPa were C: 44.2 ± 4.8, VS: 42.3 ± 8.7, VS+: 46.2 ± 7.8, VS/B: 43.0 ± 6.4, VS+/B: 44.0 ± 8.1. ANOVA revealed no significant difference (p > 0.05) between SBS of VS or VS+ and the control with or without blood present. Conclusion: This controlled laboratory study concluded that the use of ViscoStat or ViscoStat Plus as a hemostatic agent does not have a significant effect on the shear bond strength of composite resin to dentin when using Optibond Solo Plus. Keywords: ViscoStat, ViscoStat Plus, shear bond strength, composite resin contamination

Purpose: The objective of this project was to compare the microtensile bond strengths (µTBS) of five "all-in-one" adhesives using two 2-step adhesives as controls. Materials and Methods: Eighty-four extracted human molars were randomly assigned to one of three substrates: dentin, unground enamel, or ground enamel. For each substrate, specimens were randomly assigned to one of five allin- one adhesives: (1) Adper Prompt L-Pop (AP, 3M ESPE); (2) Clearfil S3 Bond (S3, Kuraray); (3) G-Bond (GB, GC America) (4) iBond (iB, Heraeus Kulzer); (5) Xeno IV (XE, Dentsply Caulk). Adper Single Bond Plus (SB, 3M ESPE) was used as a two-step etch-and-rinse control, while Clearfil SE Bond (SE, Kuraray) was used as a two-step self-etching control. Crowns were built with Filtek Z250 (3M ESPE) and sectioned in x and y directions. The resulting sticks were fractured in tension at a crosshead speed of 1 mm/min. Statistical analysis was computed for each substrate with one-way ANOVA and Duncan's post-hoc test at p 0.05. Results: Means ± SD are given in MPa; pretesting failures are shown in brackets. Dentin - SE: 79.1 ± 20.5, [0/85]; SB: 76.3 ± 19.3, [0/82]; AP: 51.6 ± 21.9, [0/90]; XE: 40.5 ± 22.9, [7/81]; S3: 27.8 ± 13.2, [7/91]; iB: 17.4 ± 15.6, [25/91]; GB: 11.7 ± 7.4, [5/92]. Unground enamel - SB: 33.1 ± 10.5, [0/69]; AP: 27.6 ± 7.5, [0/66]; S3: 24.6 ± 12.0, [0/70]; SE: 16.8 ± 11.7, [3/60]; XE 15.4 ± 14.1, [16/63]; iB: 11.2 ± 11.5, [18/64]; GB: 9.5 ± 12.4, [31/63]. Ground enamel - SB: 33.7 ± 9.1, [0/69]; AP: 33.2 ± 7.9, [0/77]; SE: 26.4 ± 9.5, [0/67]; S3: 25.5 ± 8.9; [0/56]; XE: 21.0 ± 8.9, [3/68]; GB: 18.2 ± 10.3, [4/68]; iB: 12.3 ± 8.9, [11/52]. For dentin, the Duncan's test ranked the means in 6 statistical subsets: GB Keywords: dental adhesion, acid etching, bond strength testing

Purpose: To measure the microtensile bond strength of different pit and fissure sealants in a simplified fissure model. Materials and Methods: Twenty extracted bovine mandibular permanent incisors were randomly divided into 4 groups for treatment: G1: 35% phosphoric acid/Clinpro Sealant; G2: 35% phosphoric acid/Delton; G3: Non-Rinse Conditioner/Dyract Seal; G4: 20% polyacrylic acid/Fuji IILC. Each tooth was sectioned into 6 pieces (4 x 6 mm) of buccal enamel. SEM examination was used to confirm the presence of aprismatic enamel on each tooth. Using a spacer, two pieces of etched enamel were secured to a glass slide at a mean distance of 0.6 ± 0.1 mm. The space between enamel substrates was then etched/conditioned and sealed with different materials according to the tested groups. By serially cutting each double-bonded sample, multiple beam-shaped specimens about 0.8mm2 in cross section were obtained and tested in tension (0.5 mm/min) until failure occurred at either one of the two stressed interfaces. Failure modes were classified by stereomicroscopy. Results: G1 and G2 showed statistically higher bond strengths than G3 and G4. G4 demonstrated the significantly lowest bond strength. Failures were mostly adhesive in G1, G2, G3, and mainly cohesive/mixed in G4. Conclusion: According to this model, resin-based materials (Clinpro Sealant, Delton) showed better microtensile bond strength than compomer (Dyract Seal) or resin-modified glass ionomer (Fuji IILC). Keywords: sealant, aprismatic enamel, bovine enamel, double interface, microtensile bond strength

Purpose: Laser pretreatment of dental hard tissues prior to preventive or restorative procedures has been a subject of research. Unground primary enamel bears a prismless superficial layer which is known to be acid resistant. This in vitro study was conducted in order to evaluate the potential use of Er,Cr:YSGG laser in the pretreatment of occlusal surfaces of primary teeth prior to bonded fissure sealant application. Materials and Methods: Occlusal surfaces of human primary mandibular molars were used (n =140). After pretreatment with Er,Cr:YSGG laser (group A) or not (group B), occlusal fissures were treated with one of the following in each of 7 subgroups (n = 10): 1. phosphoric acid-etch only; 2. Clearfil SE Bond; 3. FL Bond; 4. Adper Prompt L-Pop; 5. NRC+Prime & Bond NT; 6. One-Up Bond F; 7. Xeno III. All teeth were sealed with Fissurit F. The specimens were thermocycled (1000 times) and stored thereafter in distilled water at 37°C for 8 months. Following immersion in 0.5% basic fuchsin solution, three bucco-lingual sections were made from each tooth. They were digitally photographed and the extent of dye penetration along the enamel-sealant interface was measured (in mm) with image analysis software. Results: There was no difference between the Er,Cr:YSGG laser pretreated group (group A) and the nonlased group (group B) (p > 0.05). The lowest microleakage values were observed in subgroups A1 and B1. Within the laser pretreated group, subgroups A1, A4, and A5 showed lower microleakage scores when compared to subgroups A2, A3, A6, and A7 (p 0.05). As for the nonlased group, subgroups B1, B3, B4, and B5 demonstrated significantly lower microleakage scores than subgroups B2, B6, and B7 (p 0.05). Conclusion: Er,Cr:YSGG laser pretreatment was not found to influence the resistance to microleakage of bonded fissure sealant application in primary teeth. Keywords: primary teeth, laser, Er, Cr:YSGG laser, fissure sealant, microleakage, self-etching adhesive

Purpose: This study tested the effect of different drying times on the efficacy of bond for five self-etching adhesives. Materials and Methods: Four marketed and one experimental adhesive were tested in combination with a hybrid-type resin composite (Venus, Heraeus Kulzer): Clearfil Protect Bond (CPB, Kuraray), G-Bond (GBO, GC), Hybrid Bond (HYB, Sun Medical), iBond NG experimental (ING, Heraeus Kulzer), Clearfil S3 Bond (TSB, Kuraray). Three hundred twenty human molars were randomly divided into 40 separate groups. For shear bond strength (SBS) testing, the adhesives were applied to flat peripheral dentin surfaces. Following the manufacturers' specified dwell times, the adhesives were air dried for 0, 5, 10, or 20 s prior to light activation and seating of composite cylinders (n = 8). The specimens were stored for 24 h in 37°C water and submitted to shear bond strength testing at 1 mm/min. For evaluation of marginal adaptation, Venus restorations were bonded in standardized cylindrical dentin cavities (>4 mm in diameter, 1.5 mm in depth) according to the procedure above and immersed in water at 23°C for 10 min prior to removal of excess using #4000 SiC paper and determination of the maximum marginal gap widths (MGW, n = 8). Bond strength data were analyzed by one-way ANOVA and Duncan's ranking (p 0.05), and marginal adaptation by Kruskal-Wallis ANOVA and Mann-Whitney ranking (p 0.05). Results: Both SBSs and numbers of gap-free restorations increased significantly with drying time (p 0.05). All materials performed best after air drying for 10 s or longer. Conclusions: Since the optimal drying times found diverge from the manufacturer's directions for use, recommendations might need to be revised.

Purpose: To evaluate in vitro the effect of clinical primer application errors on human dentin permeability. The null hypothesis is that there is no difference in dentin permeability reduction with the use of a total-etch three-step (TE3) dentin adhesive system among the treatment groups. Materials and Methods: Seventy extracted noncarious human third molars were sectioned to obtain 0.7-mm-thick midcoronal dentin disks. The specimens were randomly assigned to 5 groups and treated with a total-etch three-step (TE3) ethanol/water-based dentin adhesive system, Optibond FL (Kerr; Orange, CA, USA), according to manufacturer's instructions using 4 simulated application errors: short application of primer by immediate drying; no primer application; no drying of primer; aggressive drying of primer. Permeability of dentin was measured as fluid filtration at baseline and after adhesive polymerization. Kruskal-Wallis and Tukey's post-hoc comparisons were used to evaluate permeability reduction differences among groups (α = 0.05). Results: The null hypothesis was rejected (p 0.0001). The data provided strong evidence that the distribution of percentage permeability reduction differed among the 5 treatment groups (p 0.0001). All possible pairwise comparisons of the groups were statistically significant. The highest mean percentage of permeability reduction was observed in the group where manufacturer's instructions were followed (99.4 ± 1.0), followed by the aggressive drying primer group (86.7 ± 11.1), the shortened primer application group (73.01 ± 12.0), the no-drying primer group (48.44 ± 19.9), and, finally, the no-primer group (22.33 ± 7.7). Conclusion: The incorrect primer application allowed significant dentin permeability. Strict adherence to recommended clinical application of dentinal adhesives is fundamental to achieve good dentin tubule sealing. Keywords: dentin bonding, permeability

Purpose: The aim of this study was to evaluate the influence of ultrasonic treatment on the bond strength of glassionomer cements to dentin. Materials and Methods: Conventional (Fuji II: a; Ketac-Fil Plus: b), resin-modified (Fuji II LC Improved: c; Photac-Fil Quick Aplicap: d), and more viscous conventional (Ketac Molar: e) glass-ionomer cements were tested. Fifty human molars were sectioned mesiodistally, embedded in epoxy resin with exposed buccal or lingual surfaces, and ground to obtain a flat dentin surface. A matrix with a central orifice in the shape of an inverted truncated cone was built with a bovine tooth and positioned on the dentin surface. In the control groups, the materials were inserted into the matrix. In the test groups, the ultrasonic treatment was applied to the surface of the matrix and the surface of the glassionomer cements. The specimens were stored in deionized water for 24 h at 37°C and subjected to bond strength tests. Data were analyzed using two-way ANOVA and Tukey's tests. Results: The mean bond strengths in MPa for the control groups were: a: 2.21, b: 1.85, c: 8.65, d: 5.93, and e: 2.10. The results for the test groups were: a: 3.33, b: 2.19, c: 9.95, d: 6.10, and e: 2.65. Ultrasonic treatment statistically increased the tensile bond strength of all tested cements (p 0.05). Conclusion: Ultrasonic treatment improved the bond strength of the glass-ionomer cements to dentin after 24 h. Keywords: ultrasonics, glass-ionomer cements, dentin, tensile strength

Purpose: Fatigue resistance of post and cores is critical to the long term behavior of restored nonvital teeth. The purpose of this in vitro trial was to evaluate the influence of the post material's physical properties on the adaptation of adhesive post and core restorations after cyclic mechanical loading. Materials and Methods: Composite post and cores were made on endodontically treated deciduous bovine teeth using 3 anisotropic posts (made of carbon, quartz, or quartz-and-carbon fibers) and 3 isotropic posts (zirconium, stainless steel, titanium). Specimens were submitted to 3 successive loading phases - 250,000 cycles at 50 N, 250,000 at 75 N, and 500,000 at 100 N - at a rate of 1.5 Hz. Restoration adaptation was evaluated under SEM, before and during loading (margins) and after test completion (margins and internal interfaces). Six additional samples were fabricated for the characterization of interface micromorphology using confocal microscopy. Results: Mechanical loading increased the proportion of marginal gaps in all groups; carbon fiber posts presented the lowest final gap proportion (7.11%) compared to other stiffer metal-ceramic or softer fiber posts (11.0% to 19.1%). For internal adaptation, proportions of debonding between dentin and core or cement varied from 21.69% (carbon post) to 47.37% (stainless steel post). Debonding at the post-cement interface occurred only with isotropic materials. Confocal microscopy observation revealed that gaps were generally associated with an incomplete hybrid layer and reduced resin tags. Conclusion: Regardless of their rigidity, metal and ceramic isotropic posts proved less effective than fiber posts at stabilizing the post and core structure in the absence of the ferrule effect, due to the development of more interfacial defects with either composite or dentin. Keywords: adhesive post and cores, fiber posts, fatigue test, confocal microscopy, scanning electron microscopy

Purpose: The aim of this study was to evaluate the influence of the operator's experience on the outcome of fiber post cementation using an etch-and-rinse acetone-based adhesive. Materials and Methods: Fifteen human anterior teeth were used in the study. One trained operator performed the endodontic procedures and prepared the roots for the insertion and cementation of the posts. At this point, teeth were divided into 3 groups and distributed to 3 operators to lute the posts: an expert operator (EO), a moderately experienced operator (ME), and an operator with a low level of experience (LE). Quartz fiber posts (DT Light Post #1 or #2, RTD) were used. Posts were cemented using Prime&Bond NT Dual Cure adhesive system (Dentsply Caulk) in combination with the dual-curing resin cement Calibra (Dentsply Caulk). The post retention was assessed with the "thin-slice" push-out test. One-way ANOVA was performed to examine the effect of the operator on push-out strength, followed by post-hoc multiple comparisons using Tukey's test, with the significance level set at α = 95%. Results: The results of push-out strength testing were as follows: EO (12.44 ± 3.63 MPa), ME (11.68 ± 2.64 MPa), LE (11.18 ± 3.12 MPa). No statistically significant differences were determined among the three groups. Conclusion: There was no statistically significant difference in the retention measured for fiber posts luted by operators with different levels of clinical experience. Given the parameters of this investigation, the level of operator experience in luting fiber posts does not affect post retention under laboratory conditions. Keywords: operator, variability, bonding, fiber posts

Purpose: The aim of the study was to clinically evaluate Empress II inlays cemented with a dual-curing bonding agent and a self-curing luting system. Materials and Methods: Forty patients were selected to receive one Empress II inlay. Empress II is a heat-pressed glass ceramic containing lithium disilicate and lithium orthophosphate crystals, purported to provide higher stress resistance and improved strength. The restorations were placed between March and May 2000. Recalls were performed after 6, 12, 24, and 36 months. At the 3-year recall, 7 patients were lost to follow-up. Inlays were evaluated for postoperative sensitivity, marginal integrity, marginal leakage, color stability, surface staining, retention, and surface crazing (microcracks). Results: At the 3-year recall, all the restorations were in place and only one showed postoperative sensitivity (at the first recall, 1 week after placement). Only 3 inlays showed slight marginal staining, and 4 inlays showed gaps, with little surface staining or microcracks. Conclusions: No inlay debonded or fractured during the observation period. All the evaluated inlays were in place and acceptable. Keywords: ceramic inlay, Empress II, clinical trial