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Effect of Ceramic Thickness and Shade on Mechanical Properties of a Resin Luting Agent
Author(s) -
Passos Sheila Pestana,
Kimpara Estevão Tomomitsu,
Bottino Marco Antonio,
Rizkalla Amin S.,
Santos Gildo Coelho
Publication year - 2014
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/jopr.12140
Subject(s) - knoop hardness test , materials science , ceramic , composite material , elastic modulus , cement , indentation hardness , microstructure
Purpose This study aimed to investigate the influence of ceramic thickness and shade on the Knoop hardness and dynamic elastic modulus of a dual‐cured resin cement. Materials and Methods Six ceramic shades (Bleaching, A1, A2, A3, A3.5, B3) and two ceramic thicknesses (1 mm, 3 mm) were evaluated. Disk specimens (diameter: 7 mm; thickness: 2 mm) of the resin cement were light cured under a ceramic block. Light‐cured specimens without the ceramic block at distances of 1 and 3 mm were also produced. The Knoop hardness number (KHN), density, and dynamic Young's moduli were determined. Statistical analysis was conducted using ANOVA and a Tukey B rank order test ( p = 0.05). Results The bleaching 1‐mm‐thick group exhibited significantly higher dynamic Young's modulus. Lower dynamic Young's moduli were observed for the 3‐mm‐thick ceramic groups compared to bleaching 3‐mm‐thick group, and no difference was found among the other 3‐mm groups. For the KHN, when A3.5 3‐mm‐thick was used, the KHN was significantly lower than bleaching and A1 1‐mm‐thick ceramic; however, no difference was exhibited between the thicknesses of the same shade. Conclusions The dual‐cured resin cement studied irradiated through the 1‐mm‐thick ceramic with the lightest shade (bleaching ceramic) exhibited a better elastic modulus, and there was no effect in KHN of the resin cement when light cured under different ceramic shades and thicknesses (1 and 3 mm), except when the A3.5 3‐mm‐thick ceramic was used. Clinical Significance Variolink II irradiated through ceramic with the lowest chroma exhibited the highest elastic modulus; therefore, the light activation method might not be the same for all clinical situations.