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Visual and quantitative analysis of the cariostatic potential and microhardness of resin composite and resin modified glass ionomer activated by argon ion laser compared to halogen light and LED

Grant number: 09/02240-3
Support Opportunities:Regular Research Grants
Duration: September 01, 2009 - August 31, 2011
Field of knowledge:Health Sciences - Dentistry - Dental Materials
Principal Investigator:Alessandra Cassoni Ferreira
Grantee:Alessandra Cassoni Ferreira
Host Institution: Universidade de Guarulhos (UNG). Campus Guarulhos-Centro. Guarulhos , SP, Brazil


An adequate polymerization of resin based dental materials of direct aplication is important for the longevity of clinic restorations. The aim of this study is to evaluate the cariostatic potential by different superficial Knoop microhardness profile in vitro of human enamel and a visual analysis by scores. The region around restorations of resin-modified glass-ionomer (RM), or a composite resin (CR) activated by halogen lamp, argon ion laser and light-emitting diode (LED) after pH challenge will be evaluated by Knoop microhardness and the indirect degree of polymerization in superficial and deeper regions. Seventy two human enamel blocks will be divided into two groups according to restorative material (RM) and (CR). Each group will be divided in three subgroups and activated by halogen lamp (H), argon ion laser (AL) or LED (LED) with 12 blocks. The intensity for halogen lamp will be 700mW/cm2 for 40s. Activation with argon ion laser will be with power of 200mW for 20s. LED intensity will be 1500mW/cm2 for 20s. Enamel blocks will be submited to thermal cicle and the pH challenge to induce caries like lesions. The visual evaluation by scores and a quantitative evaluation by Knoop microhardness profile of the caries like lesions will be carried out. The visual analysis will be performed by three double blind evaluators, previously calibrated in accordance with microleakage score criteria (0 to 3). The scores will be subjected to the Kappa test. Knoop microhardness test will be performed by four indentation 100mm of distance of the cavity restored in each enamel block. The Knoop evaluation will be perfomed at the top of the restoration by five indentation 100mm of distance at central region. The specimens will be longitudinally sectionated and five indentations will be performed 1.5mm deep. The visual analysis will be performed by representative score of each experimental unit and will be subjected to non-parametric statistical test Kruskal-Wallis and Mann-Whitney. The statistical analysis of microhardness values of the average of indentations will be used in the ANOVA followed by Tukey's test . (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FERLA, JULIANA DE OLIVEIRA; RODRIGUES, JOSE AUGUSTO; GALVAO ARRAIS, CESAR AUGUSTO; CORREA ARANHA, ANA CECILIA; CASSONI, ALESSANDRA. Influence of photo-activation source on enamel demineralization around restorative materials. Brazilian Oral Research, v. 27, n. 3, p. 286-292, . (09/02240-3)
DE SENA POPOFF, JOSIANE MARQUES; RODRIGUES, JOSE AUGUSTO; DE FREITAS ARAS, WANESSA MARIA; CASSONI, ALESSANDRA. Influence of Photoactivation Source on Restorative Materials and Enamel Demineralization. Photomedicine and Laser Surgery, v. 32, n. 5, p. 274-280, . (09/02240-3)

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