Synthesis and application of a novel star-hyperbranched poly(acrylic acid) for improved dental restoratives

Jun Zhao,Dong Xie,Yiming Weng

doi:10.4236/jbise.2010.311136

Abstract

A new star-hyperbranched poly(acrylic acid) has been synthesized and incorporated into dental glassionomer cement for enhanced mechanical strengths. The effects of arm number and branching on viscosity of the polymer aqueous solution and mechanical strengths of the formed experimental cement were evaluated. It was found that the higher the arm number and the more the branching, the lower the viscosity of the polymer solution as well as the mechanical strengths of the formed cement. It was also found that the experimental cement exhibited significantly higher mechanical strengths than commercial Fuji II LC. The experimental cement was 51% in CS, 55% in compressive modulus, 118% in DTS, 82% in FS, 18% in FT and 85% in KHN higher than Fuji II LC. The experimental cement was only 6.7% of abrasive and 10% of attritional wear depths of Fuji II LC in each wear cycle. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations.

Highlights

There are three major dental filling restoratives including dental amalgam, composite resins and glass-ionomer cements
The experimental cement was only 6.7% of abrasive and 10% of attritional wear depths of Fuji II LC in each wear cycle. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations
The strategy of increasing molecular weight (MW) of the polyacid by either introducing amino acid derivatives or N-vinylpyrrolidone has shown enhanced mechanical strengths [16,17,18]; the working properties were somehow decreased because strong chain entanglements formed in these high MW linear polyacids resulted in an increased solution viscosity [16,17]

Summary

Introduction

There are three major dental filling restoratives including dental amalgam, composite resins and glass-ionomer cements. One is to incorporate hydrophobic pendent (meth)acrylate moieties onto the polyacid backbone in GIC to make it become light- or redox-initiated resin-modified GIC (RMGIC) [12,13,14,15,17] and the other is to directly increase molecular weight (MW) of the polyacid [16,17,18]. As a result, the former has shown significantly improved tensile and flexural strengths as well as handling properties [12,13,14,15,17]. All the polyacids used in commercial GIC formulations have been linear polymers and using high MW of these linear polyacids has been limited due to the viscosity issue

Results

Discussion

Conclusion