Influence of Thermal Treatment Conditions on the Properties of Dental Silicate Cements

Georgeta Voicu,Alina Badanoiu,Florin Iordache,Alexandru Popa

doi:10.3390/molecules21020233

Georgeta Voicu, Alina Badanoiu + Show 2 more

Open Access

https://doi.org/10.3390/molecules21020233

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Journal: Molecules	Publication Date: Feb 18, 2016
Citations: 7	License type: CC BY 4.0

Affiliation: Romanian Academy, Polytechnic University of Bucharest

Abstract

In this study the sol-gel process was used to synthesize a precursor mixture for the preparation of silicate cement, also called mineral trioxide aggregate (MTA) cement. This mixture was thermally treated under two different conditions (1400 °C/2 h and 1450 °C/3 h) followed by rapid cooling in air. The resulted material (clinker) was ground for one hour in a laboratory planetary mill (v = 150 rot/min), in order to obtain the MTA cements. The setting time and mechanical properties, in vitro induction of apatite formation by soaking in simulated body fluid (SBF) and cytocompatibility of the MTA cements were assessed in this study. The hardening processes, nature of the reaction products and the microstructural characteristics were also investigated. The anhydrous and hydrated cements were characterized by different techniques e.g., X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR) and thermal analysis (DTA-DTG-TG). The setting time of the MTA cement obtained by thermal treatment at 1400 °C/2 h (MTA1) was 55 min and 15 min for the MTA cement obtained at 1450 °C/3 h (MTA2). The compressive strength values were 18.5 MPa (MTA1) and 22.9 MPa (MTA2). Both MTA cements showed good bioactivity (assessed by an in vitro test), good cytocompatibility and stimulatory effect on the proliferation of cells.

Highlights

Dental silicate cements, known as mineral trioxide aggregate (MTA) cements, are currently used in endodontic procedures for root perforation repairs and root-canal sealing [1,2,3,4,5,6,7,8,9,10,11]
The main steps of the MTA synthesis were: (a) aluminum butoxide and acetyl acetone (1:1 molar ratio) were magnetically stirred for 2 h; calcium nitrate was dissolved in distilled water and magnetically stirred until a clear solution was obtained; zinc acetate was added and the solution was magnetically stirred for 2 h at C; TEOS was added in this clear solution and the mixture was homogenized until a clear solution was obtained; the two solutions were mixed for 3 h at room temperature and kept at 80 ̋ C until a gel was formed
The results presented in this paper show that MTA cements with short setting times can be obtained by a sol-gel synthesis route and an adequate thermal treatment

Summary

Introduction

Known as mineral trioxide aggregate (MTA) cements, are currently used in endodontic procedures for root perforation repairs and root-canal sealing [1,2,3,4,5,6,7,8,9,10,11]. Compared with the solid state reaction route, the usual synthesis method for this type of materials, the sol-gel route presents some advantages like high purity of the resulted products and lower thermal treatment temperatures. The setting time of MTA silicate cements, obtained by our group using this method, is still too. The setting time of MTA silicate cements, obtained by our group using this method, is still too long [14,15], especially if dental applications are the aim; in this paper we present new MTA long [14,15], especially if dental applications are the aim; in this paper we present new MTA cement formulation, with a higher amount of 3CaO∙Al2O3, compound with high reactivity vs water. MTA cement, before and after hardening, is presented in this paper

Discussion

Granulometric

Weight losses recorded

Experimental Section

Conclusions