Varijacije rendgenske slike cementnih materijala i kompozitnih kočića zavisno od njihovog sastava i primenjene radiografske metode

Objectives. According to the International Standard Organization (ISO), the radiopacity of luting cements and dental posts should be equal to or greater than that of aluminum. The aims of these in vitro studies were: to determine the radiopacity of 13 commercially available dental luting cements and compare it with that of human enamel and dentin, to investigate the capacity of various radiopacifying agents to produce the difference in radiopacity on film and a CCD - based digital sensor, to evaluate the radiopacity of seven commercially available dental posts and determine the minimum radiopacity value necessitated for their clinical evaluation and to determine the threshold radiopacity value for detection of small thicknesses of dental luting cements in adjacent to implant abutment. Materials and Methods. Five classes of luting cements were evaluated: zinc phosphate (Cegal N and Harvard Zinc Phosphate), zinc polycarboxylate (Harvard Polycarboxylate and Hoffmann’s Carboxylate), glass ionomers (Ketac Cem Easymix, Ketac Cem Radiopaque and Fuji I), resin-modified glass ionomer (Rely X Luting), and resin cements (Multilink Automix, Variolink II, Speed CEM, Rely X Unicem Automix and Variolink Veneer). Teeth slices served as controls. Five specimens of each material measuring 8 mm in diameter and 1 mm thick were prepared and radiographed alongside tooth slices and an aluminum stepwedge using a Trophy Radiovisiography (RVG) sensor (Trophy Radiology, Cedex, France). The radiopacity values were expressed in mm Al and analyzed by the ANOVA and Tukey tests (P lt 0,05). For determination of radiographic system capacity to detect material's radiopacity depending on the radiopacifier present within experimental cements were formulated by mixing metacrylate with the following radiopacifying agents: zinc oxide (ZnO), zirconium oxide (ZrO2), titanium dioxide (TiO2), barium sulphate (BaSO4), iodoform (CHI3), bismuth oxide (Bi2O3) and ytterbium trifluoride (YbF3). Five specimens of each material were radiographed alongside an aluminum stepwedge on E speed film (Eastman Kodak Company, Rochester, NY) and a CCD - based digital sensor (Trophy Radiology). Radiopacity values were calculated by converting the radiographic densities of the specimens expressed as a mean optical densities or mean grey scale values into equivalent thickness of aluminum...U skladu sa ѕahtevima koje propisuje međunarodna organizacija za standardizaciju (ISO) rendgenkontrastnost dentalnih cemenata i dentalnih kočića treba da bude veća od rendgenkontrastnosti iste debljine aluminijuma. Ciljevi sprovedenih in vitro istraživanja bili su da se: utvrdi rendgenkontrastnost različitih vrsta dentalnih cemenata na digitalnoj radiografiji uz upotrebu CCD digitalnog senzora, ispita kapacitet različitih radiografskih metoda da se ispita rendgenkontrastnost materijala zavisno kontrastnog sredstva prisutnog u materijalu, ustanovi rendgenkontrastnost različitih vrsta dentalnih kočića i njihova minimalna klinički prihvatljiva rendgenkontrasnost i da se ispitaju mogućnosti konvencionalne i digitalne radiografije u dijagnostikovanju zaostalog viška cementa na abatmentu nakon cementiranja protetskih restauracija. Materijali i metode. Pet kategorija cemenata za cementiranje protetskih nadoknada je korišćeno: dva cink fosfatna cementa (Cegal N i Harvard Zinc Phosphate), dva cink polikarboksilatna cementa (Harvard Polycarboxylate i Hoffmann’s Carboxylate), tri glas jonomerna cementa (Ketac Cem Easymix, Ketac Cem Radiopaque i Fuji I), jedan smolom modifikovani glas jonomerni cement (Rely X Luting) i pet kompozitnih cemenata (Multilink Automix, Variolink II, Speed CEM, Rely X Unicem Automix i Variolink Veneer). Uzorci gleđi i dentina su korišćeni kao kontrola. Po pet uzoraka svakog materijala prečnika 8 mm i debljine 1 mm je pripremljeno i radiografisano zajedno sa uzorcima humanih zubnih tkiva i aluminijumskim etalonom uz pomoć Trophy RVG digitalnog senzora (Trophy Radiology, Cedex, France). Rendgenkontrastnost materijala je izražavana u ekvivalentnoj debljini aluminijuma i analizirana uz pomoć ANOVA i Tukey testa (P lt 0,05)..