title: Effect of LED curing on the microleakage, shear bond strength and surface hardness of a resin-based composite restoration.
abstract: To determine the effect of Light emitting diode (LED) curing on dental resins, microleakage, shear bond strength and surface hardness of a dental composite cured with different LEDs were determined and compared with conventional halogen curing. For microleakage, Class V cavities were restored with Esthet-X, divided into groups, and exposed to one of the curing protocols (Elipar Freelight in soft start and standard modes; Ultra-Lume 2; Spectrum 800). Standard dye penetration tests were performed and the data summarised in a 2-way contingency table of observed frequencies. The Chi-square test was used (p<0.05) to test for significant differences between the lights. For surface hardness, samples of Esthet-X were exposed to the light-curing units (LCUs). Vickers hardness was determined on the upper and the bottom surfaces. Data was subjected to statistical analysis using ANOVA (p<0.05). Shear bond strength was determined using a push out method. Comparisons (ANOVA, p<0.05) were made between the different curing protocols. No significant difference in microleakage could be demonstrated between the different LCUs at the enamel side (p=0.60). At the dentin side only the Elipar Freelight (soft start), could significantly reduce microleakage (p<0.01). The hardness score for the halogen light was significantly lower than for the LED lights (p<0.01). The Spectrum 800 and the Elipar Freelight (soft start) have significantly higher shear bond strengths than the others (p<0.01). It was concluded that the LED source is more efficient for a comparable overall power output.
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Medical University of Southern Africa, South Africa. tgo@medunsa.ac.za
authors.forename: Theunis G
authors.initials: TG
authors.lastname: Oberholzer
authors.forename: Ignatius C
authors.initials: IC
authors.lastname: Du Preez
authors.forename: M
authors.initials: M
authors.lastname: Kidd
mesh_terms: D000268:Adhesiveness / Q000528:radiation effects; D001641:Bicuspid / Q000503:physiopathology* / Q000601:surgery*; D002484:Cementation / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects / Q000627:therapeutic use*; D003763:Dental Leakage / Q000175:diagnosis* / Q000503:physiopathology; D003793:Dental Restoration, Permanent / Q000379:methods*; D004058:Diffusion / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D006244:Hardness / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D008027:Light; D010777:Photochemistry / Q000379:methods; D011829:Radiation Dosage; D012666:Semiconductors; D033081:Shear Strength; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D003188:Composite Resins; C466112:Esthet-X