الفهرس 
Effect of coffee, carbonated orange juice and artificial saliva on the fracture toughness and hardness of cemented cerasmart laminate veneers :in vitro study
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Abstract
This study designed to investigate the effect of commonly consumed beverages on the fracture toughness and hardness of cemented CERASMART laminate veneers over 24 time period incubation. A total of 36 cemented CERASMART laminate veneer on extracted central incisors were fabricated by CEREC MC XL milling machine The CERASMART ceramic laminate veneers were polished with CERASMART polishing set according to manufacturing instructions. All samples (36 samples) were divided into to three test groups as follows: group A): (12 Samples) stored in artificial saliva group B): (12 samples) stored in coffee group c): (12 samples) stored in carbonated orange juice Surface hardness, crack length and fracture toughness were measured after exposure to aging solutions, where the surface hardness was measured through vicker{u2019}s indentation as follows: Regarding surface hardness :Three indentations were made in each sample and the mean was calculated for each sample It was found thatthe highest mean ± SD value of surface hardness recorded with saliva storage (204.607±6.905 HV) then coffee storage mean value (202.796±6.014 HV) while the lowest mean ± SD value of surface hardness recorded with orange storage (201.867±7.438HV). The difference was statistically non-significant as indicated by one-way ANOVA (F=0.416, P=0.6687>0.05). While the fracture toughness was calculated by the indentation method through this equation KIC = 0.016(E/H) 0.5(P/c1.5). The data was obtained and the results were tabulated. It was found that the highest mean ± SD value of fracture toughness recorded with saliva storage (3.1769±0.2087 MPa.m1/2) then orange storage mean value (2.3216±0.1004 MPa.m1/2) while the lowest mean ± SD value of fracture toughness recorded with coffee storage (1.6975±0.0790 MPa.m1/2). The difference was statistically significant as indicated by one-way ANOVA followed by Tukey{u2019}s pair-wise post-hoc tests (F=165.8, P=0.0001<0.05)