02 June 2023

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Bioactivity, solubility of a new root canal sealer

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Introduction

The main function of root canal sealer is to create an adhesive mass with gutta-percha core and fill the gaps within the obturating material to eliminate the bacterial micro leakage as a guarantee of successful endodontic treatment. To satisfy the requirements Grossman outlined in 1988, various types of sealers with different compositions have been created. Bioceramic sealer is widely used in endodontics due to its biological characteristics. Bioactive calcium-phosphate-silicate material is the main component of bioceramic BC-sealers. Endosequence BC-sealer (Brasseler Boulevard) has been available since 2009. In several studies, it turned out to be biocompatible and nontoxic, and it boosted osteogenesis. It also encourages the production of an alkaline pH medium, which is critical for both bioactivity and antibacterial properties. However, it possesses a prolonged setting time and great solubility when immersed in water.

Objectives

This study aimed to analyze the effect of using phosphate buffer solution (PBS) on the solubility, pH changes, surface structure, and elemental composition of a new bioceramic Cerafill sealer compared with Endosequence sealer and AH26 resin-based sealer.

Methods

A fresh mixture of each sealer moistened with either deionized water or PBS was subjected to a setting time test. Set discs (n = 10) were submerged in either deionized water or PBS to evaluate pH changes and solubility at 1, 7, 14, 21, and 28 days. Surface characterization of the sealers was done before and after solubility tests using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy analyses.

Results

An analysis of variance revealed a significant delay in setting of BC-Endosequence (P < .001) with no significant difference when each sealer was moistened with deionized water or PBS (P > .05). Both bioceramic sealers exhibited highly alkaline pH (range, 9.47–10.72). When the sealer was submerged in deionized water, Endosequence exhibited significantly greater solubility, whilst Cerafill and AH26 gained weight. When the sealers were submerged in PBS, both bioceramic sealers gained more weight, with significantly greater values for Endosequence (P < .001). Hydroxyapatite formation was revealed by SEM/EDX and FTIR.

Conclusions

PBS promoted the formation of hydroxyapatite crystals that protect the bioceramic sealers from dissolving. The new bioceramic root canal sealer Cerafill can resist the solubility when immersed in water or PBS. However, the solubility of Endosequence sealer improved after submerging in PBS. Hence, the authors conclude that the latter is desirable for use in solubility testing studies in comparison to water, to simulate a clinical situation.

As the solubility percentage markedly decreased when the sealer was submerged in PBS, the latter may promote good apical seal and be considered as a guarantee for successful endodontic treatment. Further studies are needed to evaluate the adaptation ability of Cerafill root canal sealers.

Sawsan T. Abu Zeid, Arwa Alnoury, "Characterisation of the Bioactivity and the Solubility of a New Root Canal Sealer," International Dental Journal, 2023, ISSN 0020-6539, https://doi.org/10.1016/j.identj.2023.04.003.