A measure for quantifying the radiopacity of restorative resins

Abstract

Objective To evaluate the utility of the X-ray attenuation coefficient as a measure for quantifying the radiopacity of restorative resins at different exposure times and film speeds. Materials and methods Five restorative resins were made into disks, measuring 10 mm in diameter with thicknesses of 0.5, 1.0, 1.5, 2.0, and 2.5 mm. These resin disks, an aluminum step wedge, and a lead disk were placed on size 4 Ultraspeed Ò D and Insight Ò E/F films. X-ray parameters were 65 kVp, 10 mA, and 30-cm focus-to-film distance. Exposure times were 0.3, 0.15, and 0.10 s for the D-speed films and 0.15, 0.10, and 0.05 s for the E/F-speed films. At each exposure setting, three D-and E/F-speed films were exposed and processed immediately with an automatic processor. The optical density was measured with a transmission densitometer. The net optical density (D) was used to calculate the linear attenuation coefficients (l) using lnD = -lx ? lnD 0 , where D and D 0 denote the optical density of the specimen and background, respectively. Results The linear attenuation coefficients (mm -1 ) of the five restorative resins were 0.24-0.27 for Sorare Ò , 0.30-0.34 for Estelite Ò , 0.36-0.39 for Gradia Ò , 0.51-0.54 for Clearfil AP-X Ò , and 0.52-0.56 for Beautifil Ò . These were all higher than that of dentin (0.15-0.19). There was no significant difference in the attenuation coefficients at different exposure times or film speeds. Conclusions Attenuation coefficients can be used instead of aluminum wedges of equivalent thickness to quantify the radiopacity of restorative resins.

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

“…Unlike Gu et al11 and Sur et al,2 we determined that the setup changes had influenced the effect on the radiopacities of dental materials. Applying a charge-coupled device (CCD), Gu et al11 concluded that altering the exposure time and tube-target distance would not significantly change the radiopacity 11.…”

“…Applying a charge-coupled device (CCD), Gu et al11 concluded that altering the exposure time and tube-target distance would not significantly change the radiopacity 11. Moreover, using D, E, and F speed films and by means of the attenuation coefficient method, Sur et al reported that the different exposure times would not remarkably modify the radiopacity of dental materials 2. Notably, they did not consider target-tube distance as another confounder.…”

Digital evaluation of the influence of interruption of the fixation process on radiographic contrast and base-plus-fog density in three commercial brands of radiographic films

“…However, some researches have shown that under-processing occurs in a large portion of dental offices [10][11][12][13][14] , which may undoubtedly induce diagnostic errors. Lemke et al 15 , in their research, verified that the majority of professionals evaluated were performing radiographic overexposure, in order to under-process the radiographs afterwards, with the aim of reducing working time.…”

<b>Optical density evaluation around the zirconia granules used as graft in rat calvaria

“…Grafts with the use of synthetic material have various benefits, such as availability, sterilization, abundance of donors, and reduced morbidity. This eliminates many of the deficiencies of autogenous grafts (SUR et al, 2011). Synthetic materials for these purposes may be metals, polymers, composites, ceramics, and glass.…”

“…Synthetic materials for these purposes may be metals, polymers, composites, ceramics, and glass. Zirconia is a frequently used synthetic material at present, particularly in the fields of medicine and dentistry, promoting functional reestablishment with prosthetic parts in hip and femur prostheses, dental implants, and copings (AL RUHAIMI, 2001;SUR et al, 2011) as it is a highly biocompatible and inert biomaterial, like ceramics (HISBERGUES et al, 2009).…”