Toothbrush Abrasion Of Resin Coated Glass Ionomers Over 8 Years

Method: The glass ionomers tested were Fuji IX GP eXtra (GC Europe) and Riva Self Cure (SDI, Australia). The coating materials were G-Coat PLUS and Fuji Varnish. Gradia Direct Posterior was used as a control. For every group, 8 samples were tested. The abrasion test was performed according to ISO/TS 14569-1 standards and the samples were kept in SAGF medium saliva of 6.7 pH during all the test period. The samples sizes were 15x7x2 mm. The glass ionomer samples were prepared according to manufacturer’s advices and the composite controls were cured 80 sec with a halogen light. 0.01% of Rhodamine® B isothiocyanate (Merck, Germany) was inserted in the coating resins in order to make them visible. They were applied 3 min after setting and polymerized. The samples were then immersed in epoxy resin and their halves were covered with sticky tapes in order to prevent the abrasion.  The abrasion test was performed with a universal machine (Willytech, Germany) with a force of 1 N and with measurements at 2500, 7500, 20000 and 40000 cycles. The samples were duplicated (Alpha Die, Schütz Dental, Germany) and examined in 3D with a CLSMicroscope (Leica TCS SP2, Germany). The results were compared with ANOVA and Tukey HDS test at a significance level of 0.05.

Result: The difference between the groups and the cycles was significant and the control group abraded the less (p≤0.05). The uncoated groups abraded two times more than the composite group and the G-Coat groups abraded less than the Fuji Varnish groups (p≤0,05).

Conclusion: After 40000 cycles corresponding to 8 years of wear, both G-Coat PLUS covered glass ionomers abraded equally to the resin composite.