Original scientific paper

Comparison Between Standard and Pulsed Coherent Light Polymerization

Zrinka Šutalo ; Zagreb University School of Dentistry, Zagreb, Croatia
Andrej Meniga ; Zagreb University School of Dentistry, Zagreb, Croatia
Jozo Šutalo ; Zagreb University School of Dentistry, Zagreb, Croatia
Davorka Azinović ; Institute for Physics, University of Zagreb, Croatia
Goran Pichler ; Institute for Physics, University of Zagreb, Croatia

Abstract

An ever growing amount of photo-curable materials is being used in different fields of dentistry. Standard photopolymerization devices produce about 60% o f monomer conversion in composite resin fillings. In order to improve the quality of polymerization, a series of experiments was made using pulsed laser, because continuous coherent light leads to a higher polymerization shrinkage caused by a temperature rise in the material. Three different experiments were carried out with different shades of composite resins Helioprogress and Heliomolar (Vivadent, Liechtenstein). In the first experiment, the wavelength was changed from 465 to 495 nm in steps o f 5 nm with 30s exposition time. In the second one, the wavelength was constant (470 nm) and the illumination time was changeable (10, 20, 30 and 40s). The cured part of the sample, situated in a specially prepared aluminum mould, was measured with Vernier micrometer. The best results were achieved at 470 nm regardless of the amount of filler and pigment. The results were compared with a commercial device (Heliomat). It is expected that pulsed laser polymerization will improve the degree of monomer conversion, decrease a temperature rise in the composite and in that way avoid wall-to-wall contraction.

Keywords

composite resins; polymerization; pulsed laser

Hrčak ID:

99881

URI

https://hrcak.srce.hr/99881

Publication date:

15.6.1993.

Article data in other languages: croatian

Visits: 1.456 *