Abstract
To evaluate the effect of preheating glass-ionomer cement (GIC) restorative materials on stabilization time (ST) of their metal carboxylate bonds and on microhardness. Two conventional high-viscosity GICs, Ketac Universal (3M ESPE) and Equia Forte (GC), were evaluated. The thermographic camera was used to measure the temperature inside the glass-ionomer cement capsules before and after heating. The preheating of capsules was performed at 54°C for 30 seconds in a commercial device. Characterization of ST in the GICs was determined by Fourier Transform Infrared (FTIR) spectroscopy. For this, 10 samples of each material were prepared, five in the non-preheated group (control) and five with preheating. FTIR spectra were obtained 10 minutes after mixing (control group) or after heating and then every 10 minutes for 120 minutes. For the microhardness test, 20 cylindrical specimens (3 mm height x 6 mm diameter) were prepared for each material (10 preheated, 10 control). The microhardness was determined at three time intervals: 10 minutes after mixing, after the ST as detected through the FTIR part of the study, and after one week. Knoop microhardness was assessed using a diamond indenter with a 25 g load and 15 seconds dwell time. Ketac Universal showed an increase in temperatures of 15.7°C for powder and 3.6°C for liquid, while Equia Forte showed 16.4°C for powder and 8.5°C for liquid. FTIR spectra indicated that preheating reduced the ST for Equia Forte but increased it for Ketac Universal. Preheating increased the initial microhardness (T1) of Equia Forte. With maturation over one week, it was observed that preheating significantly improved the microhardness of both materials compared with the control specimens. Preheating influenced the ST and the microhardness of Ketac Universal and Equia Forte. The ST and microhardness of Ketac Universal increased after seven days, whereas Equia Forte showed a reduced ST and increased microhardness from the outset.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
