Effects of Different Acid Etching Times on the Compressive Strength of Three Calcium Silicate-based Endodontic Materials

Background: Calcium silicate cements (CSCs), if used for pulp capping or furcation repair, are covered with a restoration. The role of different time intervals of the conditioning process used for final restorations for new CSCs has not been studied. The aim of this study was to evaluate the effects of acid etching on the compressive strengths of biodentine (BD), endosequence bioceramic root repair material-fast set putty (ERRM-FSP), and ProRoot mineral trioxide aggregate (PMTA) at 24 h or 7 days. Materials and Methods: A total of 144 specimens were prepared (48 per material). For each material, 12 specimens were subjected to acid etching at 24 h or 7 days. Compressive strengths were evaluated in accordance with ISO 9917-1:2007 recommendations. Specimens were crushed along their long axis using a universal testing machine. The maximum load required to fracture each specimen was recorded in megapascals. Compressive strengths were compared with the unetched control groups. Results: For all materials, the compressive strengths were significantly higher at day 7 than at 24 h. There were no statistically significant differences between the control and etched groups at 24 h or 7 days for the materials tested. Overall, the compressive strength was significantly lower for ERRM-FSP than for PMTA and BD. Conclusion: The acid-etching procedure did not affect the compressive strength of BD, ERRM-FSP, or PMTA. However, the postponement of the acid-etching procedure until 7 days after CSC placement is suggested to reduce the possibility of displacement.