Effect of insertion method on knoop hardness of high viscous glass ionomer cements

Daniela Prócida Raggio,Willem Evert Van Amerongen,Clarissa Calil Bonifácio,José Carlos P Imparato,Marcelo Bönecker,Anton J De Gee

doi:10.1590/s0103-64402010000500011

Daniela Prócida Raggio, Willem Evert Van Amerongen + Show 4 more

Open Access

https://doi.org/10.1590/s0103-64402010000500011

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Abstract

The aim of this study was to assess the Knoop hardness of three high viscous glass ionomer cements: G1 - Ketac Molar; G2 - Ketac Molar Easymix (3M ESPE) and G3 - Magic Glass ART (Vigodent). As a parallel goal, three different methods for insertion of Ketac Molar Easymix were tested: G4 - conventional spatula; G5 - commercial syringe (Centrix) and G6 - low-cost syringe. Ten specimens of each group were prepared and the Knoop hardness was determined 5 times on each specimen with a HM-124 hardness machine (25 g/30 s dwell time) after 24 h, 1 and 2 weeks. During the entire test period, the specimens were stored in liquid paraffin at 37ºC. Significant differences were found between G3 and G1/G2 (two-way ANOVA and Tukey's post hoc test; p<0.01). There was no significant difference in the results among the multiple ways of insertion. The glass ionomer cement Magic Glass ART showed the lowest hardness, while the insertion technique had no significant influence on hardness.

Highlights

Glass ionomer cements (GICs) were first described 40 years ago by Wilson and Kent [1]
GIC became the material of choice for Atraumatic Restorative Treatment (ART) due to its well-known properties, i.e. chemical bonding to enamel and dentin, fluoride release and uptake, biocompatibility and chemical set reaction [1,2]
The GIC used in ART restorations is called “condensable” or “highly viscous” [3] and was developed for use in occlusal bearing areas

Summary

Introduction

Glass ionomer cements (GICs) were first described 40 years ago by Wilson and Kent [1]. GIC became the material of choice for Atraumatic Restorative Treatment (ART) due to its well-known properties, i.e. chemical bonding to enamel and dentin, fluoride release and uptake, biocompatibility and chemical set reaction [1,2]. Even though manufactures have reduced the wear rate and the setting time required for this material [4], hand-mixing is not very easy. If the mix is too thick or dry, it will not bond satisfactorily to the tooth structure due to the lack of polyacrylic acid available to wet the tooth substance. This is in line with the conclusion that insufficient polyacrylic acid reduces the bond strength [5]

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