The study aimed to compare shrinkage displacements of fully and partially bonded resin composite restorations (RCRs). Two groups (n=5) Class-I RCR evaluated: Group 1 (G1) fully bonded and Group 2 (G2) debonded at the floor. Experimental results were compared with predictions from simple theory and finite element analysis (FEA). The experimental linear surface displacement (LSD) was G1 62.5±5.2 µm and G2 32.8±4.0 µm. Theoretically-predicted LSD for G1 60.1±7.4 µm and G2 31.3±7.5 µm. FEA-predicted LSD were G1 65.2 µm and G2 34.6 µm. The experimental volumetric surface displacement (VSD) was G1 1.22±0.2 mm3 and G2 0.63±0.2 mm3. Theoretically-predicted VSD for G1 1.36±0.2 mm3 and G2 0.67±0.2 mm3. No significant difference (p>0.05) was found in LSD and VSD among the experimental, theoretical and FEA in the same group. Significant differences (p<0.05) were noted between the two groups, with LSD and VSD of G2 values being almost half of G1. This pattern gave an insight of a debond restoration characteristics.
Keywords: Finite element analysis; Micro-computed tomography; Polymerization shrinkage; Restoration debonding.