Objective: To determine if similar wear resistance and depth of cure (DOC) is achieved by curing composite resin with an equivalent irradiation dose from a light emitting diode (LED) vs a quartz tungsten halogen (QTH) light. Methods: The emission spectra of a QTH curing light (VIP, Bisco) and a LED light (Freelight, 3M/ESPE) were determined using a spectrograph (Spectra Pro 750, Acton Research Corp). Total power was determined with a laboratory-grade power meter. Power in the 450-490 nm range was determined by calculating the area under the spectral curve. Equivalent energy densities for the LED and QTH lights were achieved by adjusting the curing times of the lights (LED-40s, QTH-30s). DOC was determined by measuring microhardness of the top and bottom surfaces of 2mm thick disks of Esthet-X (Dentsply/Caulk) and Z-100 (3M/ESPE) cured with each light (n=3/group). Specimens were polished to 0.5 micron grit and stored in a light proof container for 24 hours prior to testing. Vickers microhardness was measured by applying a 0.5 kg load with a 15s loading cycle. Wear testing (n=10/group) was performed with the UAB wear device. A 75N contact force was applied at 1.2Hz for 100,000 cycles. Resin samples opposed stainless steel cusp-like styli. Profilometry was used to quantify localized wear of the resin. Differences between groups were assessed with ANOVA with Tukey Kramer comparison as indicated. Results: Z-100 exhibited significantly greater surface hardness (p<.001) and less wear (p<.001) compared with Esthet-X. No significant differences (p>.05) in DOC or wear were noted within each material based on curing method. Conclusions: Within the parameters of this study, LED curing is an acceptable alternative to QTH curing when equivalent energy densities are used.

Back to the Dental Materials: VI - Polymer Materials-Mechanical Properties and Degradation Program
Back to the 32nd Annual Meeting and Exhibition of the AADR (March 12-15, 2003)

Top Level Search