Assessment of Mineral Trioxide Aggregate Setting in Simulated Root Canal with Different Root Canal Wall Thickness: In Vitro Study

Radovan Žižka,Jiří Šedý,Kamila Fačevicová,Ondřej Vencálek,David Marinčák,Jan Tomáštík,Radim Čtvrtlík

doi:10.3390/app11041727

Abstract

Setting of mineral trioxide aggregate (MTA) is affected by various factors. The purpose of this in vitro study was to evaluate the influence of root canal wall thickness on mechanical properties of MTA along the whole apical plug. Bovine bone mold tubes with internal diameter of 2 mm, height of 5 mm, and wall thickness of 0.8 mm, 1.2 mm, and 1.6 mm were filled with 3 mm ProRoot MTA and were kept in 37 °C and relative humidity of 100% for 7 days. The indentation hardness and reduced modulus of elasticity were measured in a large overview matrix and detailed matrix placed 1.5 mm from simulated apical foramen in order to obtain particularized information about gradient of altering mechanical properties. The uppermost layer of material in contact with simulated apical foramen had reduced mechanical properties irrespective of root canal wall thickness. The most distinct decrease of microhardness (32%) and reduced modulus of elasticity (27%) in interfacial layer were present in specimen with thinnest root canal wall. This effect could be observed in detailed measurement up to 190 µm in material. The interfacial layer of MTA, which was in contact during setting with root canal wall thinner than 1.2 mm, had reduced mechanical properties.

Highlights

IntroductionMineral trioxide aggregate (MTA) is an essential part of today’s armamentarium for both surgical and nonsurgical endodontic procedures
The microhardness and elastic modulus mapping over the cross-section area along the longitudinal axis were employed in order to determine the possible effect of root canal wall thickness on Mineral trioxide aggregate (MTA) setting
Within limitations of this study, the interfacial layer of MTA which is in contact with root canal wall thinner than 1.2 mm has reduced mechanical properties, the same as in contact with simulated physiological conditions

Summary

Introduction

Mineral trioxide aggregate (MTA) is an essential part of today’s armamentarium for both surgical and nonsurgical endodontic procedures. It is hydraulic calcium silicate cement which sets in the presence of moisture, so it is advantageous to use it in situations, such as root perforation repair, root-end retrofill, and apical plug of immature teeth, and some authors even recommend it for complete root canal obturation [1,2]. Various powder-to-water ratios of MTA do not influence expansion of the material [4] or dimensional stability [5], adding excessive amount of water over the suggested powder-to-water ratio during mixing increases porosity, solubility [6], setting time, calcium release [7], decreases bond strength [8], and diminishes compressive strength [9]

Objectives

Findings

Discussion

Conclusion