Resin-Coated Glass Ionomer Cement Abrasion and Wear Resistance

Objectives: The objective of this study was to measure the abrasion/wear resistance and hardness of a resin coated high strength glass ionomer compared to other current restorative materials.

Methods: Four materials were evaluated: EQUIA(EQ), Fuji IX GP Extra(IX), Fuji II LC(LC) and Z-100(Z1). EQ coating, Z1, and LC were activated with 820 mW/cm² using a LE Demetron II. Toothbrush abrasion specimens (2mm x 2mm x 25mm, n=6) were tested for 20,400 cycles and the amount of volume loss calculated. Alabama wear specimens (9.5mm diameter, n=8) were tested under a load of 75 Newtons for 400,000 cycles. Four surface profiles were obtained from each specimen and volume loss was calculated using integration. Wear specimens were finished through 800 grit SiC. Knoop microhardness specimens were made (6mm diameter x 1mm thick, n=5) and values determined using the mean of the three measurements from the top surface of the specimen. Specimens for all tests were stored at 37^oC for 24h before testing. Data was evaluated using ANOVA, Tukey’s, and Wilcoxon tests (α=0.05).

Results: Abrasion loss ranged from 3.2-4.6 mm³ with LC>IX=Z1=EQ. Alabama loss ranged from 0.1-2.6 mm³ with LC>IX>EQ=Z1. Microhardness ranged from 24.2-82.3 KHN with Z1>IX>LC=EQ.

Conclusions: Coating the surface of glass ionomer restorations with a nano-filled resin coat results in increased wear resistance and decreased microhardness of the material.