Radiopacity and microhardness changes and effect of X-ray operating voltage in resin-based materials before and after the expiration date

Materials Research

Camila Tirapelli¹  Fernanda De Carvalho Panzeri¹  Heitor Panzeri¹  Luiz Carlos Pardini²  Osvaldo Zaniquelli¹ 

[1] ,University of São Paulo School of Dentistry of Ribeirão Preto Department of Dental Materials and Prosthodontics SP ,Brazil

关键词: radiopacity;    expiration date;    composites;    operating voltage;    microhardness;   

DOI  :  10.1590/S1516-14392004000300006

来源: SciELO

【 摘 要 】

This study observed alteration in the radiopacity and microhardness of expired resin-based materials compared to non-expired materials and the operating characteristics of the X-ray source used. Five 2 mm-thick cured specimens were prepared for each material: composite resins (P60®, Z100®), and a compomer (Dyract AP®). Radiopacity of the specimens was evaluated comparing the density of the resin-based material to an equivalent (mm) density of a 99.5% pure aluminum step wedge using a transmission densitometer. Surface microhardness measurements were carried out using a calibrated Vickers indenter on three different points of the same surface. ANOVA and Tukey tests (pre-set alpha = 0.05) revealed that expired materials showed no significant change in radiopacity. One material (Filtek P60) demonstrated lower radiopacity with lower KVp. Change in microhardness wa s statistically significant for Z100: for this material, the microhardness after expiration was significantly lower than before the expiration date.

【 授权许可】

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