Chemical Stability and Bond Strength of Endodontic Sealers Exposed to Acidic, Alkaline and Protein-Rich Environments: An In Vitro Investigation

Abstract

The sealing performance of endodontic sealers may be influenced by environmental factors such as pH and blood-derived proteins. This in vitro study evaluated the effects of pH variation and protein contamination on calcium ion (Ca2+) release and push-out bond strength (BS) of a calcium silicate-based sealer (Bio-C Sealer) and an epoxy resin-based sealer (AH Plus). Standardised bovine root dentine discs were immersed for 28 days in phosphate-buffered saline (PBS) at pH 5, 7 or 12, with or without 10% fetal bovine serum (FBS). Bio-C Sealer showed greater Ca2+ release and conductivity than AH Plus, with enhanced ion release in acidic and reduced in alkaline pH. Both sealers exhibited decreased BS in non-neutral pH, though Bio-C Sealer was more affected by FBS. These findings suggest that pH and protein exposure significantly alter sealer performance, with bioceramic materials being more sensitive to environmental changes than epoxy resin-based sealers.