The pursuit of resin-dentin bond durability: Simultaneous enhancement of collagen structure and polymer network formation in hybrid layers. Issue 7 (July 2021)

• Record Type: Journal Article
• Authors: Stape, Thiago Henrique Scarabello; Mutluay, Mustafa Murat; Tjäderhane, Leo; Uurasjärvi, Emilia; Koistinen, Arto; Tezvergil-Mutluay, Arzu
• Is Part Of: Dental materials. Volume 37:Issue 7(2021)
• Page Start: 1083
• Page End: 1095
• Publication Date: 2021-07
• Subjects: Dimethyl sulfoxide -- DMSO -- Ethanol -- Adhesive systems -- Bond strength -- Microtensile -- Wet bonding -- Etch-and-rinse -- Micro Raman -- Degree of conversion; Dentistry -- Periodicals; Dental materials -- Periodicals; 617.695
• DOI: 10.1016/j.dental.2021.03.010
• Languages: English
• ISSNs: 0109-5641

Abstract

Abstract: Objective: Imperfect polymer formation as well as collagen's susceptibility to enzymatic degradation increase the vulnerability of hybrid layers over time. This study investigated the effect of new dimethyl sulfoxide (DMSO)-containing pretreatments on long-term bond strength, hybrid layer quality, monomer conversion and collagen structure. Methods: H3 PO4 -etched mid-coronal dentin surfaces from extracted human molars (n = 8) were randomly treated with aqueous and ethanolic DMSO solutions or following the ethanol-wet bonding technique. Dentin bonding was performed with a three-step etch-and-rinse adhesive. Resin-dentin beams (0.8 mm 2 ) were stored in artificial saliva at 37 °C for 24 h and 2.5 years, submitted to microtensile bond strength testing at 0.5 mm/min and semi-quantitative SEM nanoleakage analysis (n = 8). Micro-Raman spectroscopy was used to determine the degree of conversion at different depths in the hybrid layer (n = 6). Changes in the apparent modulus of elasticity of demineralized collagen beams measuring 0.5 × 1.7 × 7 mm (n = 10) and loss of dry mass (n = 10) after 30 days were calculated via three-point bending and precision weighing, respectively. Results: DMSO-containing pretreatments produced higher bond strengths, which did not change significantly over time presenting lower incidence of water-filled zones. Higher uniformity in monomer conversion across the hybrid layer occurred for all pretreatments. DMSO-induced collagen stiffening was reversible in water, but with lower peptide solubilization. Significance: Improved polymer formation and higher stability of the collagen-structure can be attributed to DMSO's unique ability to simultaneously modify both biological and resin components within the hybrid layer. Pretreatments composed of DMSO/ethanol may be a viable-effective alternative to extend the longevity of resin-dentin bonds.