Regenerative Endodontics
Why Biphasic? Assessment of the Effect on Cell Proliferation and Expression

https://doi.org/10.1016/j.joen.2016.12.022Get rights and content

Highlights

  • EndoSequence BC uses 2 cement types in its formulation, making it biphasic. The materials include calcium phosphate as well as tricalcium silicate.

  • The addition of calcium phosphate modifies the material microstructure and hydration kinetics.

  • The deposition of crystalline calcium hydroxide is reduced in the set material, thus potentially limiting the material use.

  • The deterioration of biological properties of biphasic cements was verified.

Abstract

Introduction

Tricalcium silicate (TCS)–based materials are used in endodontics because they are hydraulic and interact with blood, tissue fluids, and phosphate-based root canal irrigants, resulting in biomineralization. Newer-generation materials are biphasic; calcium phosphate is added to the TCS; thus, the material has 2 cementitious phases. The effect of this addition is not known; thus, the aim of this study was to characterize biphasic cements and assess cellular proliferation and expression.

Methods

TCS cement mixed with calcium phosphate monobasic or hydroxyapatite in 1:1 proportion was prepared. The powders and the mixed cements soaked in Hank’s balanced salt solution for 28 days were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy, and X-ray diffraction analysis. Ion leaching was investigated using inductively coupled plasma mass spectroscopy. Cellular interaction with material leachate was investigated by exposing human primary osteoblasts to the leachate from the cements. Cell growth and proliferation were determined using methyltetrazolium assay and SEM.

Results

The addition of a calcium phosphate phase to tricalcium silicate changed the material hydration with a reduction in pH and calcium ion release in the leachate when calcium phosphate monobasic was added. No crystalline calcium hydroxide was formed for both biphasic materials. The biphasic cements exhibited a reduction in cell growth and proliferation. SEM of the materials showed heavy carbonation of the material surface caused by processing for microscopy.

Conclusions

The addition of a second cementitious phase results in modification of the hydration characteristics of TCS cement with deterioration of material and biocompatibility properties.

Section snippets

Materials and Methods

Tricalcium silicate cement (Mineral Research Processing, Meysieu, France) and tricalcium silicate cement mixed with either calcium phosphate monobasic (Sigma-Aldrich, St Louis, MO) or hydroxyapatite (Mineral Research Processing, Meysieu, France) in 1:1 proportion were prepared.

Characterization of Cement Powders

The results of scanning electron microscopy, EDS, and X-ray diffraction (XRD) analysis for characterization of the powders are shown in Figure 1. Tricalcium silicate and hydroxyapatite exhibited a very small particle size distribution compared with calcium phosphate monobasic. Tricalcium silicate was composed of calcium, silicon, and oxygen, and both calcium phosphate monobasic and hydroxyapatite were composed of calcium, phosphorus, and oxygen. The phase identification by XRD analysis showed

Discussion

The current research investigates the effect of the addition of 2 types of calcium phosphate cement to tricalcium silicate. In this study, the addition was done in a 1:1 basis. In the commercial versions, the percentage addition is not known, and, thus, the most extreme case scenario was set up. The unhydrated cements were characterized to gather information regarding particle sizes, shapes, and crystallinity because these features modify the hydration mechanism. The set materials after contact

Conclusions

The addition of calcium phosphate to tricalcium silicate–based materials affects the hydration of the resultant material with a reduction in the formation of crystalline calcium hydroxide and deterioration in the biological properties of the material.

Acknowledgments

The authors thank Ing James Camilleri of the Department of Metallurgy and Materials Engineering for his technical expertise, Gianella Xerri and Lawrence Spiteri for the sample processing, and ERDF (Malta) for the financing of the testing equipment through the project “Developing an Interdisciplinary Material Testing and Rapid Prototyping R&D Facility” (Ref. no. 012).

The authors deny any conflicts of interest.

References (35)

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