RESUMEN
Abstract Alternative photoinitiators with different absorption wavelengths have been used in resin composites (RCs), so it is crucial to evaluate the effectiveness of light-curing units (LCUs) on these products. Objective Using Fourier transform infrared analysis (FTIR) in vitro, the effects of varying radiant exposure (RE) values generated by second and third generation LED LCUs on the degree of conversion (DC) and maximum rate of polymerization (Rpmax) of an experimental Lucirin TPO-based RC were evaluated. Material and Methods 1 mm or 2 mm thick silicon molds were positioned on a horizontal attenuated total reflectance (ATR) unit attached to an infrared spectroscope. The RC was inserted into the molds and exposed to varying REs (18, 36 and 56 J/cm2) using second (Radii Plus, SDI) and third generation LED LCUs (Bluephase G2/Ivoclar Vivadent) or a quartz tungsten based LCU (Optilux 501/SDS Kerr). FTIR spectra (n=7) were recorded for 10 min (1 spectrum/s, 16 scans/spectrum, resolution 4 cm-1) immediately after their application to the ATR. The DC was calculated using standard techniques for observing changes in aliphatic to aromatic peak ratios both prior to, and 10 min after curing, as well as during each 1 second interval. DC and Rpmax data were analyzed using 3-way ANOVA and Tukey’s post-hoc test (p=0.05). Results No significant difference in DC or Rpmax was observed between the 1 mm or 2 mm thick specimens when RE values were delivered by Optilux 501 or when the 1 mm thick composites were exposed to light emitted by Bluephase G2, which in turn promoted a lower DC when 18 J/cm2 (13 s) were delivered to the 2 mm thick specimens. Radii Plus promoted DC and Rpmax values close to zero under most conditions, while the delivery of 56 J/cm2 (40 s) resulted in low DC values. Conclusions The third generation LCU provided an optimal polymerization of Lucirin TPO-based RC under most tested conditions, whereas the second generation LED-curing unit was useless regardless of the RE.
Asunto(s)
Fosfinas/efectos de la radiación , Resinas Compuestas/efectos de la radiación , Curación por Luz de Adhesivos Dentales/métodos , Luces de Curación Dental , Dosis de Radiación , Valores de Referencia , Factores de Tiempo , Ensayo de Materiales , Reproducibilidad de los Resultados , Análisis de Varianza , Espectroscopía Infrarroja por Transformada de Fourier , Transición de Fase , Fotoiniciadores Dentales/química , Polimerizacion/efectos de la radiaciónRESUMEN
O avanço científico que vem ocorrendo no Brasil elevou a necessitada de discussão sobre ética em pesquisa envolvendo seres humanos dentro das instituições de ensino superior. Para isso, a associação entre a arte persuasiva do cinema e a ética em pesquisa tem sido uma metodologia eficaz no que diz respeito ao processo de ensino-aprendizagem de alunos de graduação e pós-graduação. Assim, o objetivo deste projeto de extensão foi promover a discussão e o conhecimento sobre a ética em pesquisa envolvendo seres humanos com graduandos, pós-graduandos, professores e servidores públicos da Universidade Estadual de Ponta Grossa. Os resultados mostraram a efetividade do método, concluindo que os filmes contribuíram satisfatoriamente para o aprendizado e posicionamento ético de todos os participantes (AU).
The scientific advance that has occurred in Brazil increases the need to discuss ethics in human research within universities and research institutes. With this in mind, the association between the persuasive art of cinema and ethics research has been an effective methodology regarding the teaching and learning of undergraduate and graduate students. The aim of this extramural education project was to promote the discussion and understanding of ethics in human clinical research among undergraduate and graduate students, professors and public servants at Ponta Grossa State University. The results showed the effectiveness of this method. In conclusion, movies can contribute satisfactorily to the ethical learning and positioning of all participants (AU).