Methods: Two commercial RMGICs, RelyX-Luting (RX, 3M-ESPE) and Fuji-Plus (FP, GC), two control in-house liquids and four new liquid compositions (FP1, FP2, RX1, RX2) comprising different percentages of the monomer (tetrahydrofurfuryl-methacrylate) THFM with the originally used monomer (2-hydroxyethyl-methacrylate) HEMA were used in this study. In-house and experimental materials were based on the two commercial materials formulations with the corresponding powder remaining the same. Six discs were prepared for each material (16mm-diameter x 1mm-thickness). Water-uptake was measured gravimetrically. All discs were immersed in DW at 37 ̊C and weighed at regular time intervals. Percentage weight change with time was recorded. When apparent equilibriums were reached, the discs were removed from DW, weighed and placed in an oven at 37 ̊C and then weighed at regular time intervals to minimum weight.
Results: Percentage weight-change for commercial materials ranged from 5.08%±0.22 for RX and 4.75±0.26 in-house RX; 5.93%±0.32 for FP and 4.27±0.19 in-house FP. Desorption ranged from -11.74%±0.25 of RX and -12.49%±0.48 in-house RX; -8.93%±0.27 FP and -8.33%±0.19 in-house FP. All new compositions showed lower water uptake/desorption results than the commercially available products (table below).
Composition |
Weight-change %(SD) |
Desorption %(SD) |
FP1(THFM50%,HEMA50%) |
2.46(0.08) |
8.21(0.13) |
FP2(THFM30%,HEMA70%) |
2.83(0.1) |
8.58(0.09) |
RX1(THFM50%,HEMA50%) |
3.46(0.26) |
10.46(0.16) |
RX2(THFM30%,HEMA70%) |
3.37(0.18) |
10.98(0.24) |
Conclusion: Commercially available RMGIC have a drawback in their applications, due to their water-uptake and swelling, which may result in expansion stresses in both teeth and restorations, and moreover might cause fracture of ceramic restorations. Therefore, decreasing the water-uptake of these materials is highly desirable. Experimental compositions in this study have shown promising results with lower water-uptakes than commercial materials, which may lead to wider applications than commercially available products.