Original scientific paper

Some Properties of Composite Resins Cured by Pulsed Blue Laser

Zrinka Tarle ; School of Dental medicine University of Zagreb, Croatia
Andrej Meniga ; School of Dental medicine University of Zagreb, Croatia
Alena Knežević ; School of Dental medicine University of Zagreb, Croatia
Jozo Šutalo ; School of Dental medicine University of Zagreb, Croatia
Goran Pichler ; nstitute of Physics, Zagreb, Croatia
Mira Ristić ; Institut Ruđer Bošković, Zagreb, Croatia

Abstract

The purpose of the study was to analyse some properties of composite resin samples cured by pulsed laser in comparison with standard halogen light. Three hybrid and three microfilled commercial composite materials were polymerized in the experimental conditions using an excimer laser pumped dye laser (XeCl Lambda Physik LPX 100/ LPD 3002) and a standard curing unit (Heliolux GTE). The samples were spectroscopically analysed (FTIR) for the degree of conversion, scanning electron microscopy (SEM) was performed for characterising the structure of the material, and volumetric shrinkage behaviour was tested using density bottle method. Statistical analysis of the data (ANOVA p<0.05) shows that the degree of conversion values obtained by excimer laser was significantly higher for all the materials and shades tested while the polymerization shrinkage values were significantly lower compared with the conventional curing unit. Those results are clinically very important in situations whenever close approximation of the light curing tip to the composite surface is impossible. The monochromatic pulsed dye laser set at 468 nm allows high penetration into the sample and the nature of the pulse allows homogenous high quality curing with decreased shrinkage of the composite resin. The sensitivity of the tooth after the placement of direct composite restoration is mainly connected with the polymerization contraction. Adhesive and cohesive fractures appear in dentin, hybrid layer and material itself The amount of volumetric increase is in accordance with the degree of cure, the type of composite material and the nature of the activating light.

Keywords

composite resins; laser; monomer conversion; polymerization shrinkage

Hrčak ID:

94756

URI

https://hrcak.srce.hr/94756

Publication date:

15.3.1999.

Article data in other languages: croatian

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