Influence of light curing unit and ceramic thickness on temperature rise during resin cement photo-activation.
The aim of this study was to determine the effect of different ceramic thickness on heat generation during resin cement photo-activation by QTH (quartz-tungsten-halogen), LED (light emitting diode), and PAC (plasma arc-curing) LCUs (light curing units). The resin cement used was Rely X ARC (3M-ESPE), and the ceramic was IPS Empress Esthetic (Ivoclar-Vivadent), of which 0.7-, 1.4- and 2.0-mm thick disks, 0.8 mm in diameter were made. Temperature increase was recorded with a type-K thermocouple connected to a digital thermometer (Iopetherm 46). An acrylic resin base was built to guide the thermocouple and support the 1.0-mm thick dentin disk. A 0.1-mm thick black adhesive paper matrix with a perforation 6 mm in diameter was placed on the dentin to contain the resin cement and support the ceramic disks of different thicknesses. Three LCUs were used: QTH, LED and PAC. Nine groups were formed (n=10) according to the interaction: 3 ceramic thicknesses, 1 resin cement and 3 photo-activation methods. Temperature increase data were submitted to Tukey's test (5%). For all ceramic thicknesses, a statistically significant difference in temperature increase was observed among the LCUs, with the highest mean value for the QTH LCU (p<0.05). For all the LCUs, a thickness of 0.7 mm produced the highest temperatures (1.4 and 2.0mm, p<0.05). There was no difference in temperature values between the latter two thicknesses (p>0.05). The interaction of higher energy density with smaller ceramic thickness showed higher temperature increase values.
Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
Ricardo Danil
RD
Guiraldo
Simonides
S
Consani
Sarina
S
Mastrofrancisco
Rafael Leonardo Xediek
RL
Consani
Mario Alexandre Coelho
MA
Sinhoreti
Lourenço
L
Correr-Sobrinho
D000538:Aluminum Silicates; D017438:Bisphenol A-Glycidyl Methacrylate / Q000528:radiation effects; D055117:Curing Lights, Dental; D003776:Dental Porcelain; D006358:Hot Temperature; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation*; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000528:radiation effects; D011109:Polymethacrylic Acids / Q000528:radiation effects; D019279:Resin Cements / Q000528:radiation effects*
D000538:Aluminum Silicates; C075815:IPS-Empress ceramic; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D003776:Dental Porcelain; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate