Bond Strength of RMGI to Dentin using a No-Rinse Conditioner

A new paste-paste resin-modified glass-ionomer (RMGI) restorative material has been introduced recently with a new conditioner that reportedly requires no rinsing.  Objective:  The purpose of this study was to compare the shear bond strength of encapsulated RMGI (Fuji II LC, GC) and a new paste-paste RMGI (Fuji Filling LC, GC) to dentin conditioned with 20% polyacrylic acid (Cavity Conditioner, GC) or a new no-rinse conditioner (Self Conditioner, GC).   Methods:  The coronal enamel of 120 extracted human third molars was removed with a low-speed saw.  The teeth were mounted in PVC pipe with dental stone, and randomly divided into 6 groups of 20 each (n=20).  Group combinations:  1) Fuji II LC/Cavity Conditioner, 2) Fuji II LC/Self Conditioner, 3) Fuji II LC/No conditioner, 4) Fuji Filling LC/Cavity Conditioner, 5) Fuji Filling LC/Self Conditioner, 6) Fuji Filling LC/No conditioner.  The flat, sanded, dentinal surface was conditioned according to the manufacturer's instructions.  The conditioned specimens were placed in a jig (Ultradent) and the RMGI restorative materials were mixed and inserted into a mold per manufacturer's instructions in 2mm increments to a height of 3-4mm and cured for 20 seconds per increment.  All specimens were stored 24 hrs in 37⁰C distilled water before testing in shear on a universal testing machine (MTS, Insight).   A mean shear bond strength (MPa) and standard deviation were determined per group.  Data was analyzed with a two-way ANOVA/Tukeys (alpha=0.05).  Results:  A significant difference was found based on RMGI restorative material (p<0.001) and surface treatment (p<0.001), with no significant interactions (p=0.847).  Conclusions:  Fuji II LC had significantly greater bond strength to dentin than Fuji Filling LC.  The use of Cavity or Self Conditioners resulted in bond strengths which were not significantly different from each other; however, both produced greater bond strengths than the absence of conditioner.