Radiopacity and microhardness changes and effect of X-ray operating voltage in resin-based materials before and after the expiration date
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 co...
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Veröffentlicht in: | Materials research (São Carlos, São Paulo, Brazil) São Paulo, Brazil), 2004-09, Vol.7 (3), p.409-412 |
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Sprache: | eng |
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Zusammenfassung: | 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. |
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ISSN: | 1516-1439 1980-5373 1516-1439 |
DOI: | 10.1590/S1516-14392004000300006 |