IADR Abstract Archives
pH and Thermal Challenges on Marginal Fit of Veneers
Objectives: To assess the effect of pH and thermal challenges on CAD/CAM materials regarding marginal defect and fit.
Methods: Four groups (n= 10) were prepared with CAD/CAM products (Table 1). The labial surface of tooth #9 was prepared on a Typodont. A standard preparation for a ceramic laminate veneer was made as follows: a) incisal edge reduction of 1.5 mm, b) labial reduction of 0.7 mm extended to proximal contact regions, and c) a deep chamfer finish line at the cervical margin. A metal cast duplicate was then made. The preparation was scanned with the CEREC Omnicam. The digital impression was sent to the CEREC® milling unit, a new set of burs for each 10 veneers. Veneers underwent a crystallization process according to the manufacturer’s recommendations. Each veneer was placed on the master die and secured with a clamp. Fit measurements were performed using Olympus® SZX16 Stereo Microscope under a magnification of 14× with OmniMet™ 9.0 (Buehler) analysis program. Vertical marginal gap was measured at 4 previously-marked points on the facial surface. Number of marginal defects of veneers were counted.
Veneers were subjected to pH cycling solutions for 10 days, 5.0 pH solution for 6 hours and a 7.0 pH solution for 18 hours. Then thermo-cycled for 10,000 cycles between 4-5°C and 55-60°C. Statistical analysis was conducted using one-way ANOVA, the Kruskal-Wallis, the Dunn test, and the Wilcoxon sign-rank test. Bonferroni correction method was used for post-hoc pairwise comparisons. Statistical significance was predetermined at p<0.05.
Results: Emax was statistically lower in marginal gap than Vita, Grand and Celtra before cycling (Figure 1a). Grand was statistically lower in marginal gap than Vita, Emax and Celtra after cycling.
Conclusions: Grand had lower defects than Vita, Emax, and Celtra (Figure 1b). Veneers subjected to acidity may have clinical implications in the longevity of the final restoration.
Methods: Four groups (n= 10) were prepared with CAD/CAM products (Table 1). The labial surface of tooth #9 was prepared on a Typodont. A standard preparation for a ceramic laminate veneer was made as follows: a) incisal edge reduction of 1.5 mm, b) labial reduction of 0.7 mm extended to proximal contact regions, and c) a deep chamfer finish line at the cervical margin. A metal cast duplicate was then made. The preparation was scanned with the CEREC Omnicam. The digital impression was sent to the CEREC® milling unit, a new set of burs for each 10 veneers. Veneers underwent a crystallization process according to the manufacturer’s recommendations. Each veneer was placed on the master die and secured with a clamp. Fit measurements were performed using Olympus® SZX16 Stereo Microscope under a magnification of 14× with OmniMet™ 9.0 (Buehler) analysis program. Vertical marginal gap was measured at 4 previously-marked points on the facial surface. Number of marginal defects of veneers were counted.
Veneers were subjected to pH cycling solutions for 10 days, 5.0 pH solution for 6 hours and a 7.0 pH solution for 18 hours. Then thermo-cycled for 10,000 cycles between 4-5°C and 55-60°C. Statistical analysis was conducted using one-way ANOVA, the Kruskal-Wallis, the Dunn test, and the Wilcoxon sign-rank test. Bonferroni correction method was used for post-hoc pairwise comparisons. Statistical significance was predetermined at p<0.05.
Results: Emax was statistically lower in marginal gap than Vita, Grand and Celtra before cycling (Figure 1a). Grand was statistically lower in marginal gap than Vita, Emax and Celtra after cycling.
Conclusions: Grand had lower defects than Vita, Emax, and Celtra (Figure 1b). Veneers subjected to acidity may have clinical implications in the longevity of the final restoration.
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