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Objectives: The purpose of this study was to synthesize chlorhexidine (CHX)-encapsulated aluminosilicate clay nanotubes (Halloysite®, HNTs) and to incorporate them into the primer/adhesive components of an etch-and-rinse adhesive system (SBMP; Scotchbond Multipurpose, 3M ESPE) and to test their effects on degree of conversion, viscosity, immediate and long-term bonding to dentin., Methods: CHX-modified HNTs were synthesized using 10% or 20% CHX solutions. The primer and the adhesive components of SBMP were incorporated with 15wt.% of the CHX-encapsulated HNTs. Degree of conversion (DC) and viscosity analyses were performed to characterize the modified primers/adhesives. For bond strength testing, acid-etched dentin was treated with one of the following: SBMP (control); 0.2%CHX solution before SBMP; CHX-modified primers+SBMP adhesive; SBMP primer+CHX-modified adhesives; and SBMP primer+CHX-free HNT-modified adhesive. The microtensile bond strength test was performed after immediate (24h) and long-term (6 months) of water storage. Data were analyzed using ANOVA and Tukey (α=5%) and the Weibull analysis., Results: DC was greater for the CHX-free HNT-modified adhesive, whereas the other experimental adhesives showed similar DC as compared with the control. Primers were less viscous than the adhesives, without significant differences within the respective materials. At 24h, all groups showed similar bonding performance and structural reliability; whereas at the 6-month period, groups treated with the 0.2%CHX solution prior bonding or with the CHX-modified primers resulted in greater bond strength than the control and superior reliability., Significance: The modification of a primer or adhesive with CHX-encapsulated HNTs was an advantageous approach that did not impair the polymerization, viscosity and bonding performance of the materials, showing a promising long-term effect on resin-dentin bonds., (Copyright © 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the effect of the cementation strategy and mechanical cycling (MC) on the microtensile bond strength (MTBS) of feldspathic inlays cemented to premolars., Materials and Methods: Forty-eight human premolars were prepared and porcelain inlays were produced. Specimens were allocated into 3 groups, based on the cementation strategy: 1) conventional adhesive cementation (RelyX ARC, 3M ESPE): application of etch-and-rinse single bottle adhesive to dentin / ceramic surface treated with hydrofluoric acid (HF) and silane (S) / cementation with resin cement; 2) simplified cementation using a self-adhesive resin cement (RelyX U100, 3M ESPE); 3) modified simplified cementation using a self-adhesive resin cement (RelyX U100, 3M ESPE) with HF+S treatment. Half of the specimens from each group were submitted to MC (2x106 pulses, frequency = 4 Hz, load = 100 N). Each specimen was serially sliced for MTBS and the failures were classified. The stress distribution analysis using FEA was verified., Results: All of the bar-samples from G2 were lost during cutting of the specimens. Mechanical-cycling had no significant effect on bond strength, whereas cementation strategy significant affected MTBS results. The most common type of failure was cohesive of cement. FEA showed that stresses were concentrated mainly at the loading region going up to the root fixation., Conclusion: Porcelain inlays cemented with conventional resin cement or self-adhesive resin cement should be associated with ceramic surface treatment. FEA showed the most critical zone for failure is located in the cement region close to the marginal crest.

Purpose: To evaluate the effect of the cementation strategy and mechanical cycling (MC) on the microtensile bond strength (MTBS) of feldspathic inlays cemented to premolars. Materials and Methods: Forty-eight human premolars were prepared and porcelain inlays were produced. Specimens were allocated into 3 groups, based on the cementation strategy: 1) conventional adhesive cementation (RelyX ARC, 3M ESPE): application of etch-and-rinse single bottle adhesive to dentin / ceramic surface treated with hydrofluoric acid (HF) and silane (S) / cementation with resin cement; 2) simplified cementation using a self-adhesive resin cement (RelyX U100, 3M ESPE); 3) modified simplified cementation using a self-adhesive resin cement (RelyX U100, 3M ESPE) with HF+S treatment. Half of the specimens from each group were submitted to MC (2x106 pulses, frequency = 4 Hz, load = 100 N). Each specimen was serially sliced for MTBS and the failures were classified. The stress distribution analysis using FEA was verified. Results: All of the bar-samples from G2 were lost during cutting of the specimens. Mechanical-cycling had no significant effect on bond strength, whereas cementation strategy significant affected MTBS results. The most common type of failure was cohesive of cement. FEA showed that stresses were concentrated mainly at the loading region going up to the root fixation. Conclusion: Porcelain inlays cemented with conventional resin cement or self-adhesive resin cement should be associated with ceramic surface treatment. FEA showed the most critical zone for failure is located in the cement region close to the marginal crest. [ABSTRACT FROM AUTHOR]