Radiopacity of Flowable Composite by a Digital Technique

Abstract

SUMMARY The aim of this in vitro study was to evaluate the radiopacity of 19 current dental flowable composite materials by a digital technique. Digital radiographs were obtained with a CCD sensor using an aluminum step wedge, a 1-mm-thick tooth slice, and a 1-mm-thick flowable composite specimen using five different combinations of exposure and voltage. The radiopacity in pixels was determined using Digora 2.6. software. The equivalent thickness of aluminum for each material was then calculated based on the calibration curve. All of the tested flowable composite materials had higher radiopacities than that of dentin, but in almost every combination of exposure and voltage, there were some composite materials that exhibited radiopacities equal to or slightly greater than enamel p>α; α=0.01). Of the flowable composite materials tested, 37% showed lower radiopacities than enamel, and 21% of the tested materials had higher radiopacities than the 3-mm aluminum equivalent. The highest radiopacity at all exposure values was produced by the Majesty Flow and Charisma Opal Flow materials, which had radiopacities almost twice that of enamel. Flowable composite materials should have radiopacities greater than that of enamel (ISO 4049), an important consideration for the introduction of new materials to the market. The digital radiopacity analysis techniques used in this study provide an easy, reliable, rapid, and precise method to characterize radiopacity of dental flowable composite materials.

Radiopacity of Composite Luting Cements Using a Digital Technique

“…The study design was similar to previous studies . Commercially available and commonly used composite luting cements were evaluated in this study (Table ).…”

“…The aluminium step wedge (99.5% aluminium) was used as an internal standard for measuring the comparative equivalent radiopacity of different materials. In 30 random radiographs, each of the 10 steps of the aluminium step wedge was measured for density, and a graph of the density versus the thickness of the aluminium alloy at each step was constructed …”

“…The study design was similar to previous studies. 28,29 Commercially available and commonly used composite luting cements were evaluated in this study (Table 1). Three specimens of each material were prepared according to the manufacturer's instructions and injected into 1-mm-thick stainless-steel cylinders with an internal diameter of 4.1 mm.…”

“…In 30 random radiographs, each of the 10 steps of the aluminium step wedge was measured for density, and a graph of the density versus the thickness of the aluminium alloy at each step was constructed. 28,29,42 Subsequently, a calibration curve was plotted for selected data using a best-fit logarithmic regression analysis. The equivalence in thickness of aluminium for each material was calculated based on the calibration curve ( Fig 2).…”

“…In the digital imaging technique, the greyscale is inverted relative to the optical density, such that white is assigned a value of 255 (for an eight-bit image) and black is assigned a value of 0. 28 The digital technique for analyzing resin-based dental materials is a proven technique. 21,23,[28][29][30][31][32][33][34][35][36][37][38][39][40][41] Because of the increasing use of resin-based luting materials for tooth-or implant-supported restorations, it is important to analyze their radiopacity.…”