Bioactivity evaluation of calcium silicate‐based endodontic materials used for apexification

This study aims to compare the bioactivity of Biodentine, ProRoot MTA and NeoMTA Plus with regard to their element uptake (Ca, Si and Ca/P) by root canal dentine in a simulated apex (n = 30 each) and evaluate the correlation between the dentine fracture resistance (n = 30 each) and interfacial layer thickness. Specimens immersed in a corrected simulated body solution (c‐SBF) for 1, 30 and 90 days were used. In all test materials, the Ca and Si concentrations in the root dentine were found to be significantly higher, whereas the Ca/P and Si concentrations increased over time (P < 0.05). The dentine fracture resistance showed a difference at only day 30. The dentine fracture resistance of Biodentine and ProRoot MTA was positively correlated with the Si and Ca/P values, and the mean interfacial layer thickness of all specimens. A high biomineralisation capacity of ProRoot MTA and Biodentine, and their positive effects on the dentine fracture resistance during the first 30 days suggest that they may present more advantages than NeoMTA Plus in apexification treatment.     

The effect of bleaching agents on the compressive strength of calcium silicate‐based materials

The present study aimed to evaluate the effect of sodium perborate on the compressive strength of calcium silicate‐based materials. ProRoot wMTA, MTA Plus, NeoMTA Plus and Biodentine discs with 5 mm thickness and 4 mm diameter were prepared. Thirty discs from each material were used for compressive strength testing and divided into two groups: control and bleaching (n = 15). The sodium perborate was mixed with 30% hydrogen peroxide in a creamy consistency and placed on the surface of the specimens. Specimens were tested in an Instron machine, and compressive strength values were recorded and compared. The data were analysed using one‐way anova and post hoc Tukey tests. Compressive strength of all tested materials significantly decreased after bleaching (P < 0.05). SEM examination revealed deterioration on materials’ surfaces after bleaching. Application of sodium perborate and hydrogen peroxide reduced the compressive strength of ProRoot wMTA, MTA Plus, NeoMTA Plus and Biodentine.     

Effect of phytic acid on the setting times and tensile strengths of calcium silicate‐based cements

This study aimed to evaluate and compare the effect of 1% phytic acid as a mixing medium on the setting times and diametral tensile strengths of different calcium silicate‐based cements. Specimens for four experimental groups (n = 20/each) were fabricated by mixing ProRoot MTA^® (Dentsply) and Biodentine^® (Septodont) powders with their original liquids or with 1% phytic acid. Half of the samples in each group were immediately subjected to setting time tests, whereas the remaining half was subjected to the diametral tensile strength test after 3 weeks. When mixed with their original liquids, the setting time of MTA was significantly longer than that of Biodentine^® (P < 0.05). When mixed with phytic acid, the initial and final setting times of both test materials significantly decreased (P < 0.05). The diametral tensile strength of Biodentine^® was significantly greater than that of MTA (P < 0.05). However, phytic acid had no effect on this outcome (P > 0.05).     

Efficacy and retrievability of root canal filling using calcium silicate‐based and epoxy resin‐based root canal sealers with matched obturation techniques

This study aimed to compare the efficiency of root canal filling procedures and the retrievability of the filling material with various sealers. Forty‐three patients assigned to endodontic treatment with (i) continuous wave of condensation technique (CTW) with AH‐plus (ii) single‐cone technique (SCT) with EndoSeal MTA. The spent time, voids entrapping and postoperative symptoms were evaluated. To evaluate the retrievability, mandibular premolar (n = 60) were divided into four groups: AH‐plus/CTW, EndoSeal MTA/SCT, MTA Fillapex/SCT and EndoSequence BC Sealer/SCT. The time required removing the filled materials and remnant score were examined. EndoSeal MTA/SCT showed significantly shorter time of filling procedure. The number of void did not show significant differences between two techniques. No patients showed clinical signs during the follow‐up periods. There were no significant differences between group AH‐plus and EndoSeal MTA for remnant score. A certain calcium silicate‐based sealer with SCT may give similar clinical efficiencies as much as continuous‐wave technique using AH‐plus sealer.