Shear Bond Strength of RMGIC to Tooth Surface

Objectives: Paste-type resin-modified glass ionomer cements (RMGIC) are widely used because of advantages such as their ease of use.
The durability of the RMGIC is important for their long-term stable adhesion and clinical performance.
The purpose of this study was to investigate the initial adhesion of different RMGIC to teeth and their durability after thermocycling (TC).
Methods: FujiCEM Evolve (FCE; GC), Riva Cem Automix (RCA; SDI), and RelyX Luting Plus (RX; 3M ESPE) were used. Bovine teeth were embedded in acrylic resin and polished with 600-grit SiC-sandpaper to expose enamel or dentine. In addition, the adherend surfaces of stainless-steel rods were sandblasted. RMGIC was mixed, placed on the rod, and bonded to the bovine tooth, then 10N load was applied for 10sec. After excess cement was removed, the specimens were stored in an incubator at 37°C and 90%R.H. for 1hour, then at 37°C in water for 23hours. The other group was thermocycled 5000 cycles times (5-55°C, dwell time 30 sec).Shear bond strength (SBS) tests were performed (N=8, 1mm/min) and statistically analyzed (Tukey-HSD, p<0.05).
Results: Results showed that FCE and RX had comparable initial adhesion to both enamel and dentin. Also, SBS of FCE did not significantly decrease to enamel and dentin after TC. RCA had very low initial adhesion and did not adhere to dentin at all.
Conclusions: Initial adhesion strength and durability evaluation indicated that FCE had the highest SBS to dentin and enamel after TC. Therefore, it is a suitable material for clinical cases in which bond strength is required, such as low-retention preparations or high-stress locations.