Wear of Glass Ionomer Restorative Materials

Wear of posterior restorative materials is a significant clinical problem over the life of the restoration.  Objectives: To measure and compare the in vitro wear of three glass ionomer restorative materials (Riva Self-Cure LV/SDI, ChemFil Rock/Dentsply, Fuji IX/GC) and (control) a resin composite (Z100/3M ESPE) restorative material.

Methods: Eight flat disc specimens (n=8) of each material (d=10mm/h=4mm) were prepared using a flexible mold following each manufacturers' instructions.  The capsules of glass ionomer materials were mixed in an amalgamator OptiMix (Kerr) for 8 seconds at 4,000rpm. ChemFil Rock was mixed for 12 seconds and placed in the flexible mold  covered with a glass slide and allow to set. The composite resin was placed in 2mm increments in the same mold and light-cured with an Elipar S10 curing light (3M ESPE/1020mW/cm²). Specimens were stored in distilled water (24h/37șC), mounted in brass holders (d=15mm/self-cured acrylic resin), polished with a series of abrasive disc (320-, 600- and 2000- grit SiC paper) and finished (0.05” alumina slurry+polishing cloth).  The wear test was conducted on a modified UAB wear machine with a 2mm slide for 300,000 cycles using stainless steel tips (d=4.70mm) with load of 50N at 50cycles/min. 50” PMMA beads were used as the third body media (15g beads+9g water). Restorative materials were scanned before and after wear using a non-contact 3D profilometer (PROSCAN2000/Scantron/UK) to determine loss of restorative material (wear-depth and volume) by superimposing the two images (ProForm software). Data were analyzed with ANOVA and Tukey/Kramer post-hoc test (p=0.05).

Results: (Mean±SD)

Material	Volume (mm3)	Depth (”m)
Riva Self-Cure LV/SDI	0.4±0.1	52.8±13
ChemFil Rock/Dentsply	0.3±0.06	40.3±11
Fuji IX/GC	0.2±0.08	24.5±12
Z100/3M ESPE	0.02±0.002	7±3

 

Conclusions: Z100 produced significantly less wear than any of the glass ionomer materials tested (p<.0001).  Fuji IX had significantly less wear than Riva self-cure LV (p<0.05). No other differences were found.