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The effect of different power densities and method of exposure on the marginal adaptation of four light-cured dental restorative materials

Paper ID Volume ID Publish Year Pages File Format Full-Text
12531 795 2003 6 PDF Available
Title
The effect of different power densities and method of exposure on the marginal adaptation of four light-cured dental restorative materials
Abstract

Purpose: To determine whether marginal adhesion is sensitive to different irradiation parameters, we investigated the in vitro adhesion values of four dental resins on metal surfaces.Methods: Four groups of eight specimens each of Z250, Filtek flow, Dyract AP and Dyract flow were placed in pre-treated stainless steel cavities and irradiated using different methods of exposure. The curing lights used were a Spectrum 800 halogen curing light at settings of 800 and 450 mW/cm2 and an Optilux 501 ramping light. The maximum amount of push-out force required to displace the resin from the metal cavity was equated with adhesive value (shear bond strength). Comparisons (ANOVA, p<0.0001) were made within the same material and between the different materials when using different curing protocols.Results: Significant lower bond strengths were recorded when curing was done by gradually increasing the intensity (ramping method) compared to curing with the fixed intensities (p>0.0001) Comparing the fixed intensities, significant lower bond strength values were obtained at 800 mW/cm2 compared to 450 mW/cm2 (p<0.0001). For all exposures, the two flowable materials demonstrated weaker values when compared to the higher filled materials.Clinical significance: The advantage of initial slow polymerization (more elasticity and less tension) obtained by the so-called “soft start” method, was offset by a rise in total polymerization shrinkage, when final curing was completed at 1130 mW/cm2. These tests demonstrated that using halogen units, exposure for 40 s with an intensity of 450 mW/cm2 appeared to be the most promising for light-curing dental resin composites.

Keywords
Adhesion; Polymerization shrinkage; Dental resins; Shear bond strengths
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The effect of different power densities and method of exposure on the marginal adaptation of four light-cured dental restorative materials
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 24, Issue 20, September 2003, Pages 3593–3598
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us