Effect of Repeated Firings on the Color Change and Surface Roughness of Two All-ceramic Systems

Mohamed, Sherehan A.; Ahmed, Atef F.; Mekkawi, Walaa O.

doi:10.21608/adjg.2020.14214.1185

Effect of Repeated Firings on the Color Change and Surface Roughness of Two All-ceramic Systems

Document Type : Original Article

Authors

¹ Dentist at Ministry of Health, Egypt

² Professor and Head of Crowns and Bridges Department, Faculty of Dental Medicine for Girls, Al-Azhar University, Cairo, Egypt.

³ Lecturer of Crowns and Bridges, Faculty of Dental Medicine for Girls, Al-Azhar University , Cairo, Egypt.

10.21608/adjg.2020.14214.1185

Abstract

Purpose: This study aimed to evaluate the effect of repeated firings on the color change and surface roughness of two all-ceramic systems. Materials and Methods: Forty disc shaped ceramic specimens ( 10 mm x 1 mm ) were fabricated from two commercially available all-ceramic system (IPS E.max press, Ivoclar-Vivadent, Schaan, Liechtenstien, Germany and zirconia Nacera Pearl, DOCERAM Medical Ceramics, Germany) (N=20). Color measurement of the specimens was made using Reflective spectrophotometer and surface roughness (Ra) was measured using USB digital profile guage, (Elcometer 224/2, Elcometer Instruments, Great Britain) after 1, 3, 5 and 7 repeated firing. Results: The mean color change (ΔE) was clinically acceptable for both types of ceramics. As regards the effect of ceramic material on (ΔE), e.max showed statistically significantly higher mean color change (ΔE) than Zirconia. As regards the effect of repeated firings on (ΔE), 7 repeated firings showed statistically significantly higher mean (ΔE) than 5 repeated firings which in turn showed statistically significantly higher mean (ΔE) than 3 repeated firings. Surface roughness measurements showed that there were significant difference between E.max and zirconia and that zirconia showed higher mean (Ra) than e.max. Also the results of the current study showed that there were a significant difference between mean (Ra) and numbers of firing as roughness decrease with increasing the number of firing. Conclusions: Repeated firings negatively affecting the color change and surface roughness and should be minimized as possible.

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