The influences of N-acetyl cysteine (NAC) on the cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA)-based dental resin.

Yang Jiao,Meng Li,Yanwei Yang,Sai Ma,Jihua Chen,Jing Li,Lequn Shan

doi:10.7717/peerj.868

Abstract

Objectives. This study aimed to investigate the influences of N-acetyl cysteine (NAC) on cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA) dental resins.Methods. Experimental PMMA resin was prepared by incorporating various concentrations of NAC (0, 0.15, 0.3, 0.6 and 0.9 wt.%). MTT assay was performed to investigate viability of human dental pulp cells after exposure to extract of PMMA resin with or without NAC. Cell adhesion on resin specimens was examined with scanning electron microscopy. Degree of conversion was studied with Fourier Transform Infrared Spectroscopy (FTIR). Flexural strength, microhardness and surface roughness was evaluated using a universal testing machine, microhardness tester and optical profilometer, respectively.Results. Incorporation of NAC into PMMA resin significantly reduced its cytotoxicity and enhanced cell adhesion on its surface. NAC induced negative influences on the mechanical and physical properties of PMMA resin in a dose-dependent manner. The degree of conversion for all experimental PMMA resins reached as high as 72% after 24 h of polymerization. All the tested properties were maintained when the concentration of incorporated NAC was 0.15 wt.%.Conclusion. The addition of 0.15 wt.% NAC remarkably improved biocompatibility of PMMA resin without exerting significant negative influence on its mechanical and physical properties.

Highlights

Self-polymerizing poly-methylmethacrylate (PMMA)-based dental resin, consisting of a polymer powder and a liquid monomer, is one of the most frequently-used materials inHow to cite this article Jiao et al (2015), The influences of N-acetyl cysteine (NAC) on the cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA)-based dental resin
Identification of the analyte, NAC, was made based on the retention time of the NAC peaks registered for the standard solutions
This study investigated the biocompatibility and mechanical properties of PMMA resin containing different concentrations of NAC

Summary

Introduction

Self-polymerizing poly-methylmethacrylate (PMMA)-based dental resin, consisting of a polymer powder and a liquid monomer, is one of the most frequently-used materials inHow to cite this article Jiao et al (2015), The influences of N-acetyl cysteine (NAC) on the cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA)-based dental resin. It can be used for fabrication of temporary crowns, denture repair, and the temporary seal of prepared cavities. It has been reported that dental monomers reduced the intracellular levels of glutathione (GSH), an important non-enzymatic anti-oxidant that protects the cell against oxidative stress, and induces the over-production of reactive oxygen species (ROS). Such disturbance of cellular redox balance would eventually result in cell function abnormality and even cell death (Bakopoulou, Papadopoulos & Garefis, 2009; Schweikl, Spagnuolo & Schmalz, 2006)

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