Assessment of radiopacity of restorative composite resins with various target distances and exposure times and a modified aluminum step wedge

• Published in: Imaging science in dentistry 2012, 42(3), , pp.163-167
• Main Authors: Poorsattar Bejeh Mir, Arash, Poorsattar Bejeh Mir, Morvarid
• Format: Article
• Language: English
• Subjects: Original; 치의학
• ISSN: 2233-7822; 2233-7830
• DOI: 10.5624/isd.2012.42.3.163

ANSI/ADA has established standards for adequate radiopacity. This study was aimed to assess the changes in radiopacity of composite resins according to various tube-target distances and exposure times. Five 1-mm thick samples of Filtek P60 and Clearfil composite resins were prepared and exposed with six tube-target distance/exposure time setups (i.e., 40 cm, 0.2 seconds; 30 cm, 0.2 seconds; 30 cm, 0.16 seconds, 30 cm, 0.12 seconds; 15 cm, 0.2 seconds; 15 cm, 0.12 seconds) performing at 70 kVp and 7 mA along with a 12-step aluminum stepwedge (1 mm incremental steps) using a PSP digital sensor. Thereafter, the radiopacities measured with Digora for Windows software 2.5 were converted to absorbencies (i.e., A=-log (1-G/255)), where A is the absorbency and G is the measured gray scale). Furthermore, the linear regression model of aluminum thickness and absorbency was developed and used to convert the radiopacity of dental materials to the equivalent aluminum thickness. In addition, all calculations were compared with those obtained from a modified 3-step stepwedge (i.e., using data for the 2nd, 5th, and 8th steps). The radiopacities of the composite resins differed significantly with various setups (p