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Proceedings Paper

Study of the degree of photoactivation of the Z250 resin by photoacoustics
Author(s): Rick Rocha; Daniel Acosta-Avalos; Paulo Roxo Barja; Elaine Cristina dos Reis Coloiano; Airton Abrahao Martin; Luis Eduardo Silva Soares; Antonio Guillermo Jose Balbin Villaverde; Marcos Dias da Silva
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Paper Abstract

The aim of this work was to characterize the degree of photoactivation of the Z250 resin through photoacoustics. In this technique, the signal detected is proportional to the heat produced in a sample as a consequence of light absorption. This technique has been used for more than 20 years as a work tool in diverse fields of biological and biomedical sciences. Through photoacoustic measurements, it is possible to study optical and thermal properties of samples, and to obtain information on the characteristic times involved in photoinduced processes, as the photoactivation of composed resins. After application on the surface, the Z250 resin is photoactivated by incidence of continuous light (λ = 475 ± 15 nm) coming from a photodiode. This leads to the polymerization of the resin, modifying its thermal properties. The experimental method employed in this work was the following: a) the resin was applied on an aluminum sheet placed in contact with the photoacoustic cell (front incidence); b) modulated white light was applied in the lower surface of the aluminum sheet, black-painted to increase the light absorption; c) the photothermal signal was observed. Polymerization was evaluated through the alteration of the photoacoustic signal caused by the activation of the resin promoted by the incidence of the continuous light, for different activation times. The results show that the polymerization of the resin substantially modifies the photoacoustic signal, indicating that the degree of photoactivation can be evaluated through photoacoustic measurements.

Paper Details

Date Published: 3 July 2003
PDF: 5 pages
Proc. SPIE 4950, Lasers in Dentistry IX, (3 July 2003); doi: 10.1117/12.476473
Show Author Affiliations
Rick Rocha, Univ. do Vale do Paraiba (Brazil)
Daniel Acosta-Avalos, Univ. do Vale do Paraiba (Brazil)
Paulo Roxo Barja, Univ. do Vale do Paraiba (Brazil)
Elaine Cristina dos Reis Coloiano, Univ. do Vale do Paraiba (Brazil)
Airton Abrahao Martin, Univ. do Vale do Paraiba (Brazil)
Luis Eduardo Silva Soares, Univ. do Vale do Paraiba (Brazil)
Antonio Guillermo Jose Balbin Villaverde, Univ. do Vale do Paraiba (Brazil)
Marcos Dias da Silva, Instituto Nacional de Pesquisas Espaciais (Brazil)

Published in SPIE Proceedings Vol. 4950:
Lasers in Dentistry IX
Peter Rechmann; Daniel Fried; Thomas Hennig, Editor(s)

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