In Vitro Wear of Glass-Ionomer Containing Restorative Materials
Advertisements of glass-ionomer-containing restorative materials recommend suitability as load-bearing permanent or semi-permanent restorations. Historically, unacceptably high wear rates limit clinical indications of glass-ionomer-containing restorations in this regard. To compare the in vitro wear of contemporary glass-ionomer-containing dental materials commercially advertised for use in permanent dentition as load-bearing restorations in a chewing simulator. Resin composite was tested as a control. A resin-modified glass ionomer (Ionolux, VOCO gmbH), a high viscosity glass-ionomer hybrid system (Equia Forte HT with Equia Coat, GC America), and a bioactive ionic resin with reactive glass filler (Activa Bioactive Restorative, Pulpdent) were evaluated. Filtek Supreme Ultra (3M ESPE) is a visible light-activated resin composite that served as a control. Standardized flat disk-shaped specimens (n=12/group) were submitted to 500,000 cycles with continuous thermal cycling against steatite antagonists. Volumetric wear was measured at 1000, 10,000, 200,000, and 500,000 cycles. There was a statistically significant difference in mean volumetric wear for Activa Bioactive Restorative (p=0.0081, 95% CI: 0.3973, 0.4982) and Equia Forte HT (p<0.001, 95% CI: 1.2495, 1.8493), but no statistically significant difference in mean volumetric wear for Ionolux (p=0.6653) compared to control. Activa Bioactive Restorative wore approximately 60% less than, and Equia Forte HT twice more than Filtek Supreme Ultra on average, respectively. Compared to a resin composite, contemporary glass-ionomer-containing restorative materials advertised for use as load-bearing restorations display measurably variable in vitro wear rates.SUMMARY
Statement of Problem
Objective
Methods and Materials
Results
Conclusions
Estimated model-based mean wear volume as a result of chewing simulation.
Relative volumetric wear (mm3) compared to resin composite control following chewing simulation intervals. Horizontal bars represent 99.8% confidence intervals. (A) One thousand cycles. (B) Ten thousand cycles. (C) Two hundred thousand cycles. (D) Five hundred thousand cycles.
SEM of cross-sectioned Equia Forte HT and Coat specimen used in this study following chewing simulation.
Contributor Notes
Clinical Relevance
As a class of materials, contemporary glass-ionomer-containing restoratives will likely display variable wear. Until further clinical evidence is available, glass-ionomer-containing restorative materials might be used with caution as load-bearing restorations.