Analysis of the Interface between calcium silicate-based endodontic materials and root canal dentine: a pilot study

Abstract

This study evaluated by scanning electron microscopy the interface between calcium silicate-based endodontic materials (MTA and Biodentine™) and root canal dentine using three different irrigation protocols. Root canals of 66 human teeth were subjected to biomechanical preparation with ProTaper rotary instruments up to a finish file F4. The teeth were assigned into six groups according to the irrigation protocol and obturation material employed: 1A. NaOCl + MTA; 1B. NaOCl + Biodentine ™; 2A. NaOCl/NaCl/EDTA + MTA; 2B. NaOCl/NaCl/EDTA + Biodentine™; 3A. NaOCl/NaCl/CHX + MTA; 3B. NaOCl/NaCl/CHX + Biodentine™. After obturation teeth were stored for 5 days at 37⁰C in a moist environment to allow the set of sealers. One section of 3mm thick was obtained from the apical third. The specimens were immersed in PBS for 5 days. After this period of time, one specimen of each group was sectioned longitudinally into two symmetrical pieces. One of the two halves - the one with the material - was processed for morphological observation, element mapping and chemical analysis along the dentine-material interface using SEM and EDS. Along the material-dentine interface, both materials formed a tag-like structure that was more evident in groups where EDTA was used for final irrigation protocol. Apatite crystal formation was visible along the interface and within the interfacial dentine in all groups. The Ca depth was constantly larger than the Si depth but the uptake of Si was more prominent in all groups for Biodentine™. Both Biodentine™ and MTA caused the uptake of Ca and Si in the adjacent root canal dentine in the presence of PBS. The dentine element uptake for Si was more prominent in Biodentine™ than in MTA.