In vitro compressive strength and edge stability testing of directly repaired glass-ionomer cements

Jing Zhang,Avijit Banerjee,Peter Braun

doi:10.1007/s00784-019-03170-x

Jing Zhang, Avijit Banerjee + Show 1 more

Open Access

https://doi.org/10.1007/s00784-019-03170-x

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Abstract

ObjectiveTo study the repair potential of seven commercial glass-ionomer cements (GICs) using an in vitro edge compression test model.Materials and methodsA total of 448 normal and 192 repaired cylindrical specimens (6 × 4 mm) were produced from 6 GICs and one resin-modified GIC. Repaired samples consisted of a base aged for 1 month before repaired by an overlying layer. All samples were matured for 1 day, 1 week, 1 month or 3 months before compression, and edge tests were performed respectively on the whole surface (compressive strength, CS) or on the edge (edge stability, ES) using a universal testing machine.ResultsFor normal specimens, Ketac Universal (KU) illustrated a significantly higher CS than other groups at all time points (p < 0.001). ES of KU was weaker than EQUIA Forte (EQF), FIX (Fuji IX) and RSC (Riva Self Cure) after 1 day, increasing after 1 week. Repaired specimens showed CS comparable to normal specimens (p > 0.05). Repaired KU significantly improved CS compared to repaired EQF and Fuji II (FII) after 1 day. No statistical difference was found in ES among these groups (p > 0.05).ConclusionsKU provided the fastest maturation and greatest CS and ES in both normal and repair models after short-term ageing. Repair of GICs could potentially be achieved directly onto the fractured substrate and the subsequent improved mechanical performance could be maintained for at least 3 months.Clinical relevanceThis study provides a potential alternative in-vitro method to assess GIC restoration failure as well as provide insight into the mechanisms of GIC restoration repair.

Highlights

Glass-ionomer cement (GIC) is widely used as a biointeractive dental restorative material due to its aesthetic [1]Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.and anti-cariogenic properties, biocompatibility and direct adhesion to dental tissues [2]
A more recent report by Ilie [12] introduced a simplified edge testing method to evaluate GIC’s edge toughness. The results suggest this method to be reliable and could be indicative regarding the tendency of GIC materials towards chipping
ChemFil Rock (CFR), Fuji® IX GP Capsule (FIX), IonoStar Plus (ISP) and Riva Self Cure (RSC) exhibited a decrease in Compressive strength (CS) at 1 month

Summary

Introduction

The clinical use of restorative GICs includes Class I, II, III and V cavities in primary teeth as well as Class III and V cavities in permanent teeth [3]. Modern GICs have shown some clinical success in their use in posterior Class I load-bearing scenarios [4]. The major criticism of GIC is its weaker mechanical properties which limit its application in posterior load-bearing Class II restorations. A comparative study exhibited that mechanical properties, such as compressive strength, flexural strength and flexural elastic modulus, of GICs are significantly weaker than those of resin composites [5]. Bulk or margin fractures account for the predominant number of GIC tooth-restoration complex (TRC) failures [6,7,8].

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