Polymerization Kinetics, Shrinkage Stress, and Bond Strength to Dentin of Conventional and Self-adhesive Resin Cements

Abstract

Purpose: To evaluate the kinetics of polymerization and shrinkage stress of resin cements, as well as their bond strength to dentin after 24-h or one-year water storage. Materials and Methods: Three conventional resin cements were evaluated: RelyX Ultimate (RUL), Panavia V5 (PNV), and Multilink N (MLN); and three self-adhesive resin cements: RelyX Unicem 2 (RUN), Panavia SA Cement Plus (PSA), and G-CEM LinkAce (GCL). Degree of conversion (DC), maximum polymerization rate (RP<inf>max</inf>) and gel time va ues were obtained using Fourier-transform infrared spectroscopy (FTIR/ATR). Shrinkage stress values were deter mined with a tensiometer, using a universal testing machine (n=5). Indirect resin composite restorations (Solidex) were fabricated and cemented to the dentin surface using self-adhesive resin cements, or conventional resin ce ments with self-etching adhesive (n=5). Bonding performance was evaluated with the microtensile bond strength (μTBS) test after 24 h or one year of water storage. Results: MLN exhibited a higher DC (76.7%), whereas the percentage of other materials differed slightly (ranging from 54% to 58.5%). The RPm and shrinkage stress values differed significantly between the cements. PSA showed the longest gel time. Significantly higher μTBS were observed for conventional resin cements after 24-h and one-year storage; a decrease in μTBS was observed for MLN only. Conclusion: Self-adhesive resin cements may not perform as well as conventional resin cements. Although both categories of cements presented similar polymerization kinetics and shrinkage values, the self-adhesive resin ce ments showed lower μTBS compared to those of conventional resin cements. Nevertheless, storage time only af fected the bonding performance of MLN