Fluorescencia

International Journal of Clinical Dentistry Volume 3, Issue 2

ISSN: 1939-5833 © 2010 Nova Science Publishers, Inc

COMPARATIVE ANALYSIS OF FLUORESCENCE OF RESIN-BASED COMPOSITES SUBJECTED TO ACCELERATED THERMAL CYCLING UNDER VISIBLE LIGHT
K Vellasco1, FBT Pessine2, FM Flório1, GMB Ambrosano3, RT Basting1* 1 São Leopoldo Mandic School of Dentistry and Research Center, Campinas – SP, Brazil 2Institute of Chemistry, University of Campinas, Campinas – SP, Brazil 3 Dentistry School, University of Campinas, Piracicaba - SP, Brazil

Abstract
Purpose. The purpose of this study was analyze the fluorescence of different resinbased composites and dental structures subjected to thermal cycling under visible light. Fluorescence was analyzed at two distinct moments: before and after thermalcycling. Methods. Sixty specimens were made for the resin groups (n=10) of Charisma (C), Durafil (D), Esthet X (E), Herculite (H), Supreme (S), and Filtek Z250 (Z), with ten specimens prepared as a control group (DE) that consisted of sound human incisors. All specimens were submitted to the initial fluorescence analysis at 25°C in a Spectrofluorimeter SLM – AMINCO (SPF – 500F). After that theinitial evaluation, the specimens were submitted to thermal cycling at 5° and 55° C followed by a final Spectrofluorimeter analysis. The result were recorded on graphs, and transformed into numerical values to be submitted to ANOVA. Results. The comparison between groups and teeth, and initial and final values, was made using the Dunnett test (p>0.05). The comparison between resin-based compositegroups was made with Tukey‟s test (p>0.05). The mean initial fluorescence area values were: C: 28444.53; D: 26460.01; E: 14455.51; H: 14480.79; S: 35522.33; Z: 30518.72 and DE: 7265.91. The final fluorescence area values were: C: 14158.76; D: 24887.67; E: 8086.15; H: 13256.38; S: 19489.58; and Z: 17645.40. Esthet X showed similar fluorescence before and after thermal cycling. After thermal cycling,the Charisma and Herculite groups also had fluorescence similar to that of the tooth group. Clinical significance. Thermal cycling influenced resin-based composite fluorescence values. All resin-based composites showed different fluorescence values when compared before and after thermal cycling.

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K. Vellasco, F.B.T. Pessine, F.M. Flório et. al.

Introduction
Resin-based composites havebeen widely used as esthetic restorative materials, to mimic the shade of natural teeth, giving this material physical properties that are infinitely superior to those of other direct restorative materials.[1] The phenomenon of fluorescence occurs when an object absorbs luminous energy and diffuses it to a visible spectrum. In nature, this phenomenon is creased by the ultraviolet (UV) rays ofsunlight, which have a very short wavelength and is invisible to the human eye. Natural teeth exposed to ultraviolet light exhibit fluorescence in an emission spectrum that varies from white to light blue.[2] Anusavice[1] mentioned that sunlight, photographic flashlights, certain types of steam lamps and ultraviolet lights used for decorative lighting are sources of light that contain substantialamounts of almost ultraviolet radiation. The energy that the tooth absorbs is converted into light in longer wavelengths, between 400 – 500 nm, with a bluish-white color, as a fluorescent material. The healthy human tooth emits fluorescent light when excited by 365 nm UV light radiation, presenting a polychromatic fluorescence with greater intensity in the region of 450 nm of the visible lightspectrum.[3] The color of fluorescent substances is influenced by the amount of ultraviolet (UV) component in the illumination. The color of fluorescent dental resin-based composites may change by the amount of UV component in the ambient light.[4] The basic components of restorative materials are not fluorescent.[2] Some restorative materials and ceramics for anterior teeth are formulated with...