The comparative evaluation of the color stability of two ceramic systems with varying thickness and frequency of firing: an invitro study.
Journal Title: International Journal of Dental Science and Innovative Research (IJDSIR) - Year 2019, Vol 2, Issue 3
Abstract
Introduction : Color matching between ceramic restorations has become a major challenge in dentistry. Usually completed restorations do not match the shade guide , as esthetics of many ceramics gets affected by translucency . Ceramic translucency can be affected by many factors , including thickness , microstructures and the number of firing cycles. Failure in achieving appropriate shade of theprosthesis may result in great esthetic inconvenience for both the patient as well as the clinician. Aim : To evaluate the color stability of two Ceramic systems Aluminium oxide and Zirconium oxide and to study the effect of ceramic thickness (0.5mm , 1mm , 1.5mm ) and number of firings (3,5,7) on the color stability of Aluminium oxide and Zirconium oxide Ceramic systems. Materials and methods: 21 disc shaped specimens 10mm in diameter and 0.6mm core thickness are made from Aluminium oxide Ceramic systems as well as Zirconium oxide ( 4mm diameter and 10mm core thickness). These two Ceramic systems are divided into 3 groups (n=7) veneering with dentin ceramic thicknesses as 0.5,1,1.5mm . Repeated firing (3,5,7) are performed and color of the specimens is compared with the color after the initial firing. Color differences among Ceramic specimens are measured using a spectrophotometer (SpectroshadeTM micro-MHT s.p.a) and data expressed in CIE lab system coordinates.Results: Increase in Ceramic thickness resulted reduction in L* values and increase in a* and b* values for both Aluminium oxide and Zirconium oxide. Increase in number of firings resulted decrease in L* values making the specimen darker. Increase in a* and b* values making the specimens redder and yellower in Chroma. Discussion: This invitro study measured the color changes of ceramic specimens prepared at different thicknesses (0.5, 1, 1.5mm) and fired at 3, 5, 7 times. The results of this study support the hypothesis that color differences would be noted relative to firing times and dentin ceramic thicknesses. There were significant differences in color changes within groups. In the current study, the specimens had ceramic thicknesses of 0.5, 1, or 1.5 mm, with a core thickness of 0.6 mm for Aluminium oxide and 1mm for Zirconium oxide.Conclusion: Lab values of Aluminium oxide and Zirconium oxide were affected by number of firings and Ceramic thicknesses . Lab values of Aluminium oxide and Zirconium oxide were affected by number of firings and Ceramic thicknesses.
Authors and Affiliations
Dr. Keerthi Palagiri
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