Imaging Sci Dent.  2012 Jun;42(2):89-93. 10.5624/isd.2012.42.2.89.

How does duration of curing affect the radiopacity of dental materials?

• Poorsattar Bejeh Mir A
• Poorsattar Bejeh Mir M

• KMID: 1974414
• DOI: http://doi.org/10.5624/isd.2012.42.2.89

Abstract

PURPOSE
Clinicians commonly encounter cases in which it is difficult to determine whether adjacent radiopacities are normal or pathologic. The ideal radiopacity of composite resin is equal to or higher than that of the same thickness of aluminum. We aimed to investigate the possible effects of different curing times on the post-24-hour radiopacity of composite resins on digital radiographs.
MATERIALS AND METHODS
One mm thick samples of Filtek P60 and Clearfil resin composites were prepared and cured with three regimens of continuous 400 mW/cm2 irradiance for 10, 20 and 30 seconds. Along with a 12-step aluminum step wedge, digital radiographs were captured and the radiopacities were transformed to the equivalent aluminum thicknesses. Data were compared by a general linear model and repeated-measures of ANOVA.
RESULTS
Overall, the calculated equivalent aluminum thicknesses of composite resins were increased significantly by doubling and tripling the curing times (F(2,8)=8.94, p=0.002). Notably, Bonferroni post-hoc tests confirmed that the radiopacity of the cured Filtek P60 was significantly higher at 30 seconds compared with 10 seconds (p=0.04). Although the higher radiopacity was observed by increasing the time, other comparisons showed no statistical significance (p>0.05).
CONCLUSION
These results supported the hypothesis that the radiopacity of resin composites might be related to the duration of light curing. In addition to the current standards for radiopacity of digital images, defining a standard protocol for curing of dental materials should be considered, and it is suggested that they should be added to the current requirements for dental material.

Keyword

Radiography, Dental, Digital; Composite Resins; Light-Curing of Dental Adhesives

MeSH Terms

Aluminum
Composite Resins
Dental Materials
Light
Light-Curing of Dental Adhesives
Linear Models
Radiography, Dental, Digital
Aluminum
Composite Resins
Dental Materials

Figure

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  Fig. 1 Each sample is irradiated in the five different poles: upper right, lower right, lower left and upper left plus the central zone.

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  Fig. 2 The random sets of prepared samples are arranged on an occlusal photostimulable phosphor (PSP) receptor along with a 12-step aluminum step wedge.

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  Fig. 3 Varying trends of absorbencies of Filtek P60 and Clearfil with different curing regimens (10, 20, and 30 seconds curing time).

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