Improving bonding to eroded dentin by using collagen cross-linking agents: 2years of water storage.

Abstract

The aim of this study was to investigate the effects of collagen cross-linking agents on nanomechanical and bonding properties of eroded dentin (ED), 24h and 2years after water storage. Human molar dentin surfaces, eroded by soft drinks or citric acid, were acid-etched and treated with primers containing proanthocyanidin (PA) and riboflavin (RI) or were untreated (control) and tested after 24h and 2years. After acid etching and adhesive application (Prime&Bond Elect (PBE); Scotchbond Universal (SBU); Tetric n-bond Universal (TEU)), specimens were sectioned into beams and tested for microtensile bond strength (μTBS) and silver nitrate deposition (NL) after 24h and 2years. The beams were used to evaluate the 24-h in situ conversion of degree (DC). Nanohardness (NH) and Young's modulus (YM) were evaluated via resin-bonded dentin slices after 24h and 2years. A three-way ANOVA and Tukey's test were used for statistical analysis (5%). For both storage times, ED with citric acid resulted in lower μTBS, NH, and YM and higher NL for each adhesive system than soft drink ED (p < 0.05). After 2years of water storage, cross-linking primers maintained the μTBS, NH, and YM (p < 0.05) when compared with the control group. Althougth, the NL values decreased for all groups after 2 years of water storage, PA and RI treatments showed NI values lower than control group (p < 0.001). No significant differences were observed between PA and RI treatments (p > 0.05). Cross-linking primers maintain or improve DC (p < 0.03). In general, TEU and SBU yielded higher μTBS, DC, NH, and YM and lower NL than PBE. Cross-linking agents improved the results and maintained the resin-ED interface bonding and nanomechanical properties, without jeopardizing adhesive polymerization. Cross-linking agents are a viable alternative for improving and maintaining resin-ED interface bonding and nanomechanical properties.