Evaluation of pH Variation and the Release of Calcium Ions in three Endodontic Sealing Cements: BioRoot RCS, MTA Fillapex, and Acroseal

Abstract

Introduction: For several years, calcium silicates have proven to be very useful in numerous endodontic or restorative clinical situations. Derived from Portland cement and later from Mineral Trioxide Aggregate (MTA), a new generation of calcium silicate-based cement is marketed. To meet the requirements of endodontic sealing cements, several modifications according to the original formulation of calcium silicate and several additives have been implemented to create materials with excellent physical properties and endowed with the biological properties of MTA. Aim: The objective of the present in vitro study was to evaluate the variation in pH and the release of calcium ions in three endodontic cements over a period of time ranging from 3 hours to 28 days. The evaluation involved the following cements: BioRooT RCS (a pure calcium silicate-based endodontic cement), MTA Fillapex (a Mineral Trioxide Aggregate-based endodontic cement), and Acroseal (a calcium hydroxide-based endodontic cement). Materials and Methods: In this in vitro study, three root canal sealant cements were compared. A total of fifty-eight samples were prepared, and they were divided into three groups: Group 1 included 18 samples of BioRoot RCS, group 2 involved 18 samples of MTA Fillapex, and Group 3 included 18 samples of Acroseal. The samples were prepared and inserted into the molds. Then, the molds were immersed in glass test tubes containing 10 ml of double-distilled deionized water. A control tube, containing no material, was also prepared for each group. After each experimental period, the samples were taken from the tubes using sterile tweezers and weighed after 3 hours, 24 hours, 48 hours, 7 days, 14 days, and 28 days, respectively. The liquid in which the samples were previously immersed was used for measuring pH and the release of Ca ++ ions. Measurements of pH were carried out with a pH meter, previously calibrated using a buffer solution (pH 7). Measurement of the release of calcium ions was carried out using the technique of complexation of calcium ions with ethylene-diamine-tetra-acetic-acid, better known by the acronym EDTA. Statistical analysis was performed using data processing software, SPSS Statistics v.21.0. In this analytical study, two statistical tests were used for data analysis: A two-factor ANOVA test and a linear regression test for comparison of quantitative variables. Results: The results of the present study showed that compared to other materials, BioRoot RCS had the greatest calcium ion release, an ion release that is prolonged over time and which remains markedly high. The analytical study showed that BioRoot RCS had higher pH and calcium ion release values than the other two materials. These values are statistically significant (p<0.05) with a strong correlation between the release of calcium ions and the variation in pH. Conclusion: BioRoot RCS, a cement based on pure calcium silicate, showed an alkalinizing activity and an ion release power clearly superior to those of sealers based on MTA and calcium hydroxide. This is largely correlated with the chemical composition and the physicochemical behavior of the material.