Effect of silver diamine fluoride on the longevity of the bonding properties to caries-affected dentine.

OBJECTIVES: This study aimed to evaluate the adhesive properties in dentine after the application of silver diamine fluoride (SDF) on carious dentine lesions immediately and after 2 years of water storage. METHODS: 96 human molars used were subjected to artificial dentine caries production, and then randomly divided into 12 experimental groups according to 1. application of an SDF solution (carious dentine lesion without SDF treatment [control], with 12 % silver diamine fluoride [SDF 12 %] or 38 % silver diamine fluoride [SDF 38 %]); 2. Universal adhesives (Clearfil Universal Bond Quick [CUQ] and Single Bond Universal [SBU]); 3. adhesive strategy (etch-and-rinse [ER] and self-etch [SE]). After restoration, the specimens were sectioned and submitted to the microtensile bond strength test (µTBS) and energy-dispersive X-ray spectrometry analysis (SEM/EDX). All tests were performed immediately and after 2 years of water storage. Data from the µTBS were analyzed using four-way ANOVA and Tukey's test (α = 0.05). RESULTS: Only the interaction of factors 'SDF' vs 'time' was significant (p = 0.03). After 2 years of storage, the groups where SDF was applied showed higher µTBS values compared to the control group. No significant decrease in µTBS values was observed for SBU when comparing immediate and 2-year results, but a significant reduction in µTBS values was observed after 2 years for CUQ. CONCLUSION: Independent of the adhesive strategy, the use of SDF may be a promising alternative to maintain the bonding of universal adhesives to carious dentinal lesions. CLINICAL SIGNIFICANCE: This study may clarify and support clinicians regarding the longevity of resin-based restoration in caries-affected dentine treated with silver diamine fluoride.

Effect of the Absence of HEMA on the Bonding Properties of Universal Adhesive Systems Containing 10-MDP: An In Vitro Study.

OBJECTIVES: To evaluate the absence of 2-hydroxyethyl methacrylate (HEMA) on the adhesive properties with enamel and dentin of universal adhesive systems containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP). METHODS AND MATERIALS: One hundred and twelve caries-free third molars were used to test adhesion to dentin (n=64) and enamel (n=48). For each substrate, teeth were divided into eight experimental groups: four different adhesives each using two adhesive strategies. The adhesives used were: (1) Scotchbond Universal (SBU, 3M Oral Care, St Paul, MN, USA) as a HEMA-containing universal adhesive; (2) Gluma Bond Universal (GBU, Kulzer, Hanau, Germany); (3) Solare Universal Bond (SUB, GC, Tokyo, Japan); and (4) Zipbond Universal (ZIP, SDI, Victoria, Australia) as HEMA-free universal adhesives. The adhesive strategies used were etch-and-rinse (ER) and self-etch (SE). For dentin tests, the occlusal third of the crown of all teeth was removed and an adhesive protocol was applied. After completing the restoration, specimens were sectioned into bonded sticks (0.8 mm 2) and tested for microtensile bond strength (µTBS), in situ degree of conversion (DC), and nanoleakage (NL) by scanning electron microscopy. For enamel tests, teeth were sectioned into four parts (buccal, lingual, and proximal), and an adhesive protocol was applied. After completing the restoration, the specimens were tested for their microshear bond strength (µSBS). For in situ degree of conversion (DC) and nanoleakage (NL) evaluation of enamel, the specimens were sectioned in slices to be evaluated. The data for each substrate were subjected to two-way ANOVA and Tukey's test (α=0.05) for each property evaluated. RESULTS: The SBU and ZIP adhesives showed the highest µSBS, and DC (dentin and enamel) and lower NL (dentin) values compared to GBU and SUB (p=0.001). However, SBU showed better results in terms of µTBS and µSBS (SE strategy), and DC (dentin and enamel) than ZIP. Strategy ER presented higher values of µTBS and µSBS when compared to strategy SE (p=0.001), except for SBU. CONCLUSION: The effect of the absence of HEMA in commercial universal adhesive systems on enamel and dentin adhesive properties appears to be material-dependent.

Are universal adhesives in etch-and-rinse mode better than old 2-step etch-and-rinse adhesives? One-year evaluation of bonding properties to dentin.

OBJECTIVES: This study compared the bonding properties of dentin of three 2-step etch-and-rinse adhesives (2-ERAs) to those of three universal adhesives (UAs) applied with an etch-and-rinse strategy (ER), immediately and after 1 year of water storage. METHODS: Sixty caries-free molars were divided into 6 groups according to the adhesive systems used (n = 10). The 2-ERA systems included were: 1) Adper Single Bond 2 (SB), 2) Tetric N-Bond (TB), and 3) Ambar (AM); and the UAs systems were: 4) Single Bond Universal (SBU) 5) Tetric N-Bond Universal (TBU), and 6) Ambar Universal (AMU). The occlusal third of each tooth was removed and the adhesives were applied. After the composite build-up, specimens were sectioned and tested for microtensile bond strength (µTBS) and nanoleakage (NL) immediately and after 1 year of water storage. In situ degree of conversion (DC) was only evaluated in the immediate time. For water sorption (WS), solubility (SO), and mass change (MC) tests, 48 disk-shaped specimens were prepared (n = 8) and assessed according to ISO 4049:2009. RESULTS: UAs showed higher µTBS and lower NL values than 2-ERAs did after 1 year of water storage (p = 0.001). Regarding DC, 2-ERAs showed higher DC values than UAs (p = 0.001). Regarding WS, 2-ERAs showed higher WS values than those of UAs (p = 0.00001), except for AM and AMU. Lower WS was observed for AM than for other 2-ERAs (p = 0.00001). CONCLUSION: The use of UAs applied with the ER strategy seems to be a more effective technique for maintaining adhesion to dentin substrate than 2-ERAS. CLINICAL SIGNIFICANCE: This study may support clinicians in selecting the most adequate adhesive system to be used in ER strategy in dentin, demonstrating that UAs were more effective, considering the longevity of the resin restorations.