Dentin bond strength evaluation between a conventional and universal adhesive using etch-and-rinse strategy

Aim: The aim of this study was to compare the microtensile bond strength (μTBS) and the characteristics of the adhesive interface of Scotchbond Universal - SU – etch-and-rise mode (3M ESPE) and Adper Scotchbond Multi-Purpose - MP (3M ESPE) to dentin over time. Methods: Class I cavity preparations were performed in 60 human molars that were randomly divided according to the dentin bonding system (DBS) used (n=30): (1) Acid conditioning + SU and (2) Acid conditioning + MP. For bonding strength (BS) analysis, 30 teeth (n = 15) were sectioned into sticks and submitted to the microtensile test in a universal testing machine after 24 hours and 12 months. The adhesive interface of the others 30 teeth was analyzed in a confocal microscope after 24 hours and 12 months. The data of μTBS were analyzed by two-way repeated measures ANOVA and Tukey’s HSD (α = 0.05). Results: SU presented the lowest DBS compared to MP (p=0.000). Time did not influenced DBS for both adhesive systems (p=0.177). Confocal microscopy analysis showed no cracks between both adhesive systems tested. Conclusion: The results indicate that MP - μTBS showed a better performance compared to SU in total-etch mode.

Influence of different photoinitiators on the resistance of union in bovine enamel: an in vitro study

To evaluate the action of photoinitiators on the microtensile resistance of adhesive systems and resins composed in bovine enamel. Forty dental fragments, with flat and smooth enamel surfaces, obtained from the coronary buccal face of healthy bovine incisors, were randomly assigned to 4 experimental groups (n = 10) according to the different adhesive systems and composite resins used: Group 1- Ambar APS + Vittra APS; Group 2- Ambar APS + Opallis; Group 3- Ambar + Vittra APS; Group 4- Ambar + Opallis. After composite restoration, the samples were sectioned to obtain toothpicks that were subjected to the microtensile test (1.0 mm/min). The data obtained were subjected to statistical analysis. The Kruskal-Wallis test revealed no significant differences between groups (p <0.05). Values ​​in MPa were: G1- 18.58 MPaa; G2 - 19.83 MPaa; G3- 19.87 MPaa; G4- 20.99 MPaa. The result of the Mann-Whitney test showed no significant differences due to the adhesive (Ambar Universal- 19.58 MPaa, Ambar APS Universal- 19.87 MPaa) and the composite resin used (Vittra APS- 19.52 MPAa, Opallis - 20.56 MPAa). The use of different photoinitiators in the composition of adhesive systems and restorative composites did not influence their adhesive resistance values ​​due to the standardization of the factors that influence their cure pattern.

Effect of Methods of Biosilicate Microparticle Application on Dentin Adhesion

Restorative procedures associated with bioglasses have shown to be a strategy to satisfy the contemporary concept of minimally invasive dentistry. Thus, the aim of this study was to evaluate bond strength to dentin treated by two different methods of biosilicate microparticle application. Dentin surfaces from 30 sound human molars were exposed and randomly assigned into three groups (n = 10) according to the surface treatment: (1) blasting with biosilicate microparticles (distance = 1 cm/pressure = 5 bar/time = 1 min); (2) 10% biosilicate microparticles paste; and (3) control (no treatment). After, dentin surfaces were restored with self-etch adhesive (Adper Easy Bond) and nanofilled composite (Filtek Z350). Specimens were sectioned perpendicularly to the adhesive interface to obtain sticks (cross-section area = 1 mm2), which were submitted to microtensile test (0.5 mm/min; 50 kgf). Data were analyzed by ANOVA and Tukey’s test (α = 5%). Dentin/adhesive interfaces were morphologically analyzed by scanning electron microscopy (SEM). Data analysis showed that biosilicate-treated groups reached similar results (p > 0.05) and both of them demonstrated higher values (p < 0.05) than control group. SEM micrographs revealed hybridization with clear resin tags and no separation between resin-dentin adhesive interfaces. Within the limitations of this study, surface treatment with biosilicate positively influenced the adhesion to dentin and does not alter the morphology of the adhesive interface.

Self-etching Primers vs Acid Conditioning: Impact on Bond Strength Between Ceramics and Resin Cement

SUMMARY This study tested whether a self-etching surface agent and the conventional hydrofluoric acid (HF) would provide the same bonding capacity between resin cement and feldspathic (Fd) and lithium disilicate (Ld) ceramics. Ceramic blocks were cut with a low-speed diamond saw with water cooling (Isomet 1000, Buehler, Lake Bluff, IL, USA) into 20 blocks of 5 × 7 × 4 mm, which were ground flat in a polishing machine (EcoMet/AutoMet 250, Buehler) under water cooling. The blocks were randomly divided into eight groups (n=5), according to ceramic type (Ld or Fd), surface conditioning (HF + Monobond Plus or Etch and Prime), and aging by thermocycling (TC or absence-baseline). After 24 hours in 37°C distilled water, blocks were embedded into acrylic resin and 1-mm2 cross-section beams composed of ceramic/cement/composite were obtained. The microtensile test was performed in a universal testing machine (DL-1000, EMIC, São José dos Campos, Brazil; 0.5 mm.min−1, 50 kgf load cell). Bond strength (MPa) was calculated by dividing the load at failure (in N) by the bonded area (mm2). The fractured specimens were examined under stereomicroscopy, and one representative sample of each group was randomly selected before the cementation and was further used for analysis using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). The self-etching agent showed the highest bond strength for Fd (24.66±4.5) and Ld (24.73±6.9) ceramics and a decrease in surface wettability. SEM and EDS showed the presence of similar components in the tested materials with different topographies for both. Therefore, the self-etching primer was able to deliver even higher bonding than HF+silane to a resin cement.

Degradation of Multimode Adhesive System Bond Strength to Artificial Caries-Affected Dentin Due to Water Storage

SUMMARY The purpose of this study was to evaluate the influence of water storage on bond strength of multimode adhesive systems to artificially induced caries-affected dentin. One hundred twelve sound bovine incisors were randomly assigned to 16 groups (n=7) according to the dentin condition (sound; SND, artificially induced caries-affected dentin; CAD, cariogenic challenge by pH cycling for 14 days); the adhesive system (SU, Scotchbond Universal Adhesive; AB, All-Bond Universal; PB, Prime & Bond Elect; SB, Adper Single Bond 2; and CS, Clearfil SE Bond), and the etching strategy (etch-and-rinse and self-etch). All adhesive systems were applied under manufacturer's instructions to flat dentin surfaces, and a composite block was built up on each dentin surface. After 24 hours of water storage, the specimens were sectioned into stick-shaped specimens (0.8 mm2) and submitted to a microtensile test immediately (24 hours) or after six months of water storage. Bond strength data (MPa) were analyzed using three-way repeated-measures analysis of variance and post hoc Tukey test (α=5%), considering each substrate separately (SND and CAD). The etching strategy did not influence the bond strength of multimode adhesives, irrespective of the dentin condition. Water storage only reduced significantly the bond strength to CAD. The degradation of bond strength due to water storage was more pronounced in CAD, regardless of the etching strategy.

Role of Proteolytic Enzyme Inhibitors on Carious and Eroded Dentin Associated With a Universal Bonding System

SUMMARY Objectives: The aim of this study was to evaluate the effect of proteolytic inhibitors on the bond strength of a universal adhesive system (etch-and-rinse mode) applied to artificial carious and eroded dentin. Methods: Ninety molars were prepared and randomly divided into three groups according to the substrate: N, no challenges; ACD, artificial carious dentin simulation and ERO, artificial erosion simulation with orange juice. All groups were redivided into three subgroups according to the dentin pretreatment: W, water; CHX, 2% digluconate chlorhexidine; and E-64 (trans-epoxysuccinyl-L-leucylamido-[4-guanidino] butane), 5 μM E-64 inhibitor. They constituted a total of nine groups (n=10): N-W, N-CHX, N-E64, ACD-W, ACD-CHX, ACD-E64, ERO-W, ERO-CHX, and ERO-E64. All specimens were restored with Adper Single Bond Universal/Filtek Z250. Beams (0.64 mm2) were obtained and subjected to the microtensile test (μTBS) in a universal testing machine at 0.5 mm/min. The failure mode of the interfaces was determined by optical microscopy (40× magnification). Data were statistically analyzed by three-way analysis of variance and Tukey tests (p&lt;0.05). Results: All individual factors (p&lt;0.0001) and the interaction between substrate and treatment (p=0.0011) and between substrate and time (p=0.0003) were statistically significant. The caries substrate contributed negatively to bond strength. Chlorhexidine reduced bond strength for normal and eroded conditions. Only the normal substrate was negatively affected by time despite the pretreatment. Conclusions: The universal bonding system appears to be a promising bonding strategy for the maintenance of bond strength to affected dentin. E-64 did not affect bonding to the dentin in contrast to the use of chlorhexidine, which, when associated with the universal system, did affect the microtensile bond strength for artificial carious dentin.

CVD and diamond tips: can then influence the bond strength of a total-etch adhesive to dentin?

Data (MPa) were analyzed by two-way ANOVA (Surface treatment X Etching time) and Tukey's test (5%). Results and conclusions: Surface treatment with CVD tips (27.70 ± 4.04a) produced significantly higher bond strength values compared to diamond tips (23.96 ± 5.83b), and 5 second etching time on dentin produced similar bond strength values when compared to 10 and 15 second etching times. Objectives: Evaluate the microtensile bond strength of a total-etch adhesive to dentin, using a CVD tip and a diamond tip to use in dentin preparation and varying the etching time. Material and method: The dentin from the buccal face of sixty bovine teeth was exposed and prepared using two different methods (n=30): Group 1 (DT) – a diamond tip on a high-speed handpiece; and Group 2 (CVD) – a CVD tip on an ultrasonic handpiece. Each group used 37% phosphoric acid and was divided into three subgroups, according to the etching time (n=10): Subgroup 5 - 5 seconds; Subgroup 10 - 10 seconds; and Subgroup 15 - 15 seconds. The teeth were restored with Single Bond adhesive and the composite resin Herculite Classic. The specimens were subjected to thermomechanical wear (mechanical cycling/100.000 cycles, thermal cycling/1.000 cycles). Stick-like specimens were obtained and submitted to a microtensile test in a universal testing machine.