Clinical wear of approximal glass ionomer restorations protected with a nanofilled self-adhesive light-cured protective coating.

Daniela Hesse,Cornelis Johannes Kleverlaan,Clarissa Calil Bonifácio,Daniela Prócida Raggio

doi:10.1590/1678-7757-2018-0094

Abstract

High viscous glass ionomer cement (GIC) has gained popularity as a restorative material; however, high wear is pointed as one of the major drawbacks of this material. Protective surface coatings were developed to protect GIC from water contamination with the additional advantage of occluding any surface cracks or porosities commonly found in this material, possibly resulting in an increased wear resistance of the restorations.Objective:The objective of this study was to investigate the clinical wear of GIC approximal restorations in primary molars protected either with a nanofilled self-adhesive light-cured protective coating (NPC) or with petroleum jelly.Material and Methods:Approximal caries lesions in primary molars from 32 schoolchildren previously enrolled in another clinical trial were included in this investigation. GIC restorations were performed according to the Atraumatic Restorative Treatment approach and protected with either petroleum jelly or a NPC. Impressions of the restored hemiarch were done after 1 day and 6, 12, 24 and 36 months. The impressions were scanned in a 3-D appliance and the obtained images were superimposed using an appropriate computer software. Two-way ANOVA for repeated measures and Tukey's post-hoc test were used to analyze the wear of restorations (α=5%).Results:A significant difference was found between the two groups, with a wear protection offered by the application of a NPC. Conclusion: These results suggest that the application of a NPC has a protective effect on the clinical wear of approximal GIC restorations in primary teeth.

Highlights

High viscous glass ionomer cement (GIC) has gained popularity in contemporary dentistry, especially in pediatric dentistry, where this material is considered a viable option to restore dental caries lesions.3 The main advantages attributed to this material are the ease of use due to its bulk application and acceptable physical-mechanical properties, the last property is a result from its high powder/liquid ratio (3:1 to 4:1)
The setting of GIC occurs in the presence of water, as the polymeric acids needs this medium to releases protons, starting the acid reaction and setting of the material
The objective of this study was to investigate the clinical wear of approximal GIC restorations in primary molars protected with a nanofilled self-adhesive light-cured protective coating (NPC) compared to restorations protected with petroleum jelly

Summary

Introduction

High viscous glass ionomer cement (GIC) has gained popularity in contemporary dentistry, especially in pediatric dentistry, where this material is considered a viable option to restore dental caries lesions. The main advantages attributed to this material are the ease of use due to its bulk application and acceptable physical-mechanical properties, the last property is a result from its high powder/liquid ratio (3:1 to 4:1). The setting of GIC occurs in the presence of water, as the polymeric acids needs this medium to releases protons, starting the acid reaction and setting of the material. During this reaction, the hydrated protons of the acid interact with the glass particles and release metal ions. Some soluble salts such as calcium polyacrylates are formed and gradually replaced by insoluble aluminum polyacrylate salts, leading to the hardening of the cement This process occurs 24 h after the material’s mixing and during this period the GIC is sensitive to water exchanges, which may interfere in the material’s mechanical properties.. If the setting reaction happens in a dry environment, the GIC tends to lose water, which results in dimensional changes, adhesion problems and the formation of internal cracks, reducing the material’s strength.

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