Evaluation of chemical composition and radiopacity of different calcium hydroxide pastes
Author(s): Loureiro MAZ, Barbosa MG, Chaves GS, Siqueira PC, Decurcio DA
Key words: hidróxido de cálcio; medicação intracanal; composição química.
Objective: To evaluate and compare the chemical composition and radiopacity of different calcium hydroxide pastes. Material and methods: Three commercial pastes were evaluated: Ultracal XS®; Hydropast® and Callen®. Calcium hydroxide P.A. was used as a control. To evaluate the chemical composition of the materials, a sample of each paste was evaluated by thermogravimetric analysis and the mass of calcium hydroxide presented was obtained through stoichiometric calculations from the thermal decomposition of its molecules. To evaluate the radiopacity were analyzed 03 samples for each group. Radiopacity was evaluated with an ExpressTM indirect digital radiography system and FocusTM X-ray equipment. The images were analyzed as gray value standards using ImageJ software. Results: The percentages of mass of calcium hydroxide obtained for each material were: calcium hydroxide P.A.: 87.12%; Ultracal XS®: 36.38%; Hydro- past®: 30.66%; Callen®: 50.54%. The gray values of the pastes were: 63.41 for the calcium hydroxide P.A.; 126.35 for Ultracal®; 106.73 for Hydropast®, and 72.23 for Callen®. In the same analysis, the aluminum scale presented in values: Al 1mm: 53,50; Al 4 mm: 98.06; Al 8mm: 162.14; Al 12mm: 205.4. Conclusions: There were differences in all pastes between the amount of calcium hydroxide reported by the manufacturer and the amount found in the thermogravimetric analyzes. The commercial pastes tested showed higher radiopacity than the control group. Ultracal XS®was the material with the highest radiopacity, followed by Hy-dropast® and Callen®.
