Comparison of opacity and transmission of veneered ceramic restorative materials using three instruments

Abstract

Purpose: This study aims to compare the mean opacity and direct transmission of different veneered ceramic materials and study the change of translucency as a function of thickness. Materials and methods: Ten core materials were measured: 1. Cercon (Dentsply); 2. IPS e.max CAD (Ivoclar, vivadent); 3. Everest (Kavo); 4. InCoris ZI (Sircona) 5. In-Ceram Spinell (Vita Zahnfabrik); 6. In-Ceram YZ (Vita Zahnfabrik); 7. In-Ceram Zirconia (Vita Zahnfabrik); 8. In-Ceram A1 cubes AL-20 (Vita Zahnfabrik); 9. Lava Zirconia (3M ESPE); 10. In-Ceram Alumina (Vita, Zahnfabrik). Specimens were prepared according to manufacturers' instructions. Each core material was veneered with Mark II 1M1 in different thicknesses (0.5 mm, 1 mm, 1.5 mm and 2 mm) resulting in three sets of 0.5 mm core material + 0.5 mm MarkII 1M1, 0.5 mm core material+1mm Mark II 1M1, 0.5 mm core material + 1.5 mm and 0.5 mm core material + 2 mm MarkII 1M1; N=3. Lava Zirconia (3M ESPE) and In-Ceram Alumina (VITA Zahnfabrik) had an extra set of veneered MarkII 1M1 (0.5, 1, 1.5 and 2 mm); N=4. Each set of specimens was measured using three Spectrophotometers Color i5 (Gretag Macbeth), EasyShade (Vita) and EasyShade compact. All specimens were measured with air (between core and veneer layers), then Canada balsam and measured, then cleaned with Ethanol and cemented with RelyX cement (3M ESPE) and measured again. Statistical analysis: One-way analysis of variance (ANOVA) was performed to determine the presence of significant differences among mean opacity and direct transmission values of each veneer thickness group. Tukey's multiple comparison tests were used to analyze the data at 0.05 1evel of significance. Results: ANOVA test revealed differences within veneer thickness groups of materials. At [alpha]=0.05 Tukey multiple comparison tests indicated that increasing the thickness of veneer materials (0.5, 1, 1.5 and 2 mm) resulted in a significant increase in opacity (P[less than]0.05) and significant decrease in direct transmission (P[less than]0.05) for all veneered core materials tested using Spectrophotometer Color i5. Linear regression test revealed a strong negative correlation between opacity and direct transmission at [alpha]=0.05.