Synthesis, characterization, and aging resistance of the polyurethane dimethacrylate layer for dental restorations

Abstract

In this study, polyurethane dimethacrylate (PUDMA) was synthetized from different components and incorporated into a direct resin composite restoration system with the aim to buffer tooth–resin interfacial stresses and maintain the marginal adaptation. The tensile strength, elongation at fracture (ε), and thermal stability of the PUDMA layer were characterized, showing a tensile strength of 22 MPa, an ε of 112%, and a thermal decomposition temperature of about 282°C. In addition, the degree of conversion, water sorption/solubility, hydrophobicity, microtensile bond strength (μTBS), marginal leakage, and cytotoxicity in vitro were evaluated for the PUDMA layer. The data were analyzed using one‐way ANOVA, except for leakage depths (which were analyzed using the Wilcoxon paired‐rank test). The level of significance was set at 0.05. Compared with dental adhesives, PUDMA displayed a higher degree of conversion, lower water sorption/solubility, and improved hydrophobicity and biocompatibility in vitro. After thermocycling, the μTBS of the restoration system containing PUDMA had increased compared with the μTBS at 24 h. Restorations containing PUDMA showed lower leakage depths than those which did not contain PUDMA. In conclusion, because of its hydrophobic and elastic nature, the PUDMA layer, when used as an intermediate between tooth and resin restoratives, may buffer interfacial stresses, improve the stability and durability of the bonding interface, and reduce microleakage.

Cytotoxicity of contemporary resin‐based dental materials in contact with dentin

“…Several factors may play a role in the polymerization of resin‐based materials, and these factors account for the presence of unreacted components. These include material formulation, contact with oxygen, distance from the light‐curing source, degree of polymer crosslinking, and polymer vitrification (4‐11). Unreacted monomers can leach into the mouth or within dentin tubules and cause cytotoxicity problems, such as irritation of pulp or soft tissues surrounding restorations (12,13).…”

In Search of Novel Degradation-Resistant Monomers for Adhesive Dentistry: A Systematic Review and Meta-Analysis

“…After removing the duplicates, 120 articles were selected for the initial screening. After reading the title and abstract, a total of 30 studies were eligible for full-text reading, which included 4 studies retrieved in the manual search [ 26 , 27 , 28 , 29 ]. Out of these 30, 23 studies were excluded, since 11 only tested immediate bond strength (24 h), 4 used bovine teeth and 8 did not perform tensile, microtensile, shear or microshear bond strength measurements.…”

A novel resin cement to improve bonding interface durability

“…Some researchers prepared elastic layers adhesives that partially buffer shrinkage stress and obtained satisfactory aging and bonding properties. 9,10 However, cement-bonded prostheses require adhesives with even better mechanical properties to perform their functions. This research group developed a new PU system by introducing a phenyl ring to increase the rigidity of the PU system, adjusted the elasticity of the system by adjusting the proportions of polyester and polyether, and nally synthesized a novel resin cement.…”