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Aim: The literature has not yet reported investigations about the effect of laser photobiomodulation (LPBM) over the cytotoxicity of drugs for endodontic treatments. Thus, the aim of this study was to evaluate, in vitro, the effect of the association between LPBM and intracanal medications on fibroblasts viability in different exposure times. Methods: Calcium hydroxide (Ca(OH)2) and iodoform (IO) were used pure or associated to LPBM. Eluates of medications were prepared and placed in contact with the cells in three different periods: 24h, 48h and 72h. Laser irradiation (emitting radiation λ 660nm, power density of 10mW, energy density of 3 J/cm²) has been performed in two sessions within a six hour interval, for 12s per well. After each experimental time, the colorimetric assay (MTT) has been performed. Statistical analysis was applied for Mann-Whitney test with 5% α error admitted test. Results: At 24h, the use of LPBM did not increase cell viability while after 72h cell proliferation was stimulated in the group without medications. LPBM application did not increase cell viability in Ca(OH)2 group and IO at any tested time. Ca(OH)2 cytotoxicity at 24h was higher than iodoform, while at 72h not difference was observed. Therefore, after 72 hours was no statistical difference between the IO and Ca(OH)2 groups. Conclusion: LPBM was able to increase cell viability in 72h in the group without medication, although no improvement was observed in the other groups. Thus, LPBM was not able to reduce the cytotoxic effects of the materials on fibroblasts in vitro

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Introduction: Endodontic medications contain toxic components that cause varying degrees of inflammation. Objective: This study evaluated the effect of laser therapy on the inflammatory response induced by intracanal medications implanted into the subcutaneous tissue of rats using a quantitative analysis of mast cells. Material and Method: Polyethylene tubes containing the medications were implanted in the dorsum of 60 rats divided into six groups, including HS (P.A. calcium hydroxide paste), HL (P.A. calcium hydroxide paste and laser therapy), HPS (P.A. calcium hydroxide paste with camphorated paramonochlorophenol), HPL (P.A. calcium hydroxide paste with camphorated paramonochlorophenol and laser therapy), IS (iodoform with saline) and IL (iodoform with saline and laser therapy). The animals were euthanized eight or fifteen days after surgery, and samples were removed and embedded in paraffin. Histological sections were stained with 0.2% toluidine blue for the quantification of mast cells. Analysis of variance (ANOVA) and Tukey's post-hoc test were applied to determine significant differences in the number of mast cells between groups (p<0.05). Result: There was a decrease in mast cells for the HL, HPL and IL groups when compared with the HS, HPS and IS groups at both time points. There was no statistically significant difference between the HPS and HPL groups at the eight-day time point. Conclusion: Laser therapy was effective at modulating the inflammatory response induced by endodontic medications by significantly reducing the number of mast cells. .

Introdução: Medicamentos endodônticos apresentam componentes tóxicos que provocam algum grau de reação inflamatória. Objetivo: Este estudo avaliou o efeito da laserterapia na resposta inflamatória causada por medicações intracanais, em tecido subcutâneo de ratos, por meio da análise quantitativa de mastócitos. Material e Método: Tubos de polietileno contendo as medicações foram implantados no dorso de 60 ratos, distribuídos em seis grupos: HS (pasta de hidróxido de cálcio P.A.); HL (pasta de hidróxido de cálcio P.A. e laserterapia); HPS (pasta de hidróxido de cálcio P.A. com paramonoclorofenol canforado); HPL (pasta de hidróxido de cálcio P.A. com paramonoclorofenol canforado e laserterapia); IS (iodofórmio e soro fisiológico) e IL (iodofórmio, soro fisiológico e laserterapia). Os animais foram eutanasiados oito e quinze dias após a cirurgia, as peças cirúrgicas foram removidas, processadas para inclusão em parafina e os cortes histológicos corados em Azul de Toluidina 0.2%, para quantificação dos mastócitos. A análise de variância (ANOVA) e o teste de Tukey post hoc foram aplicados para determinar diferenças significativas entre os grupos quanto ao número de mastócitos (p<0.05). Resultado: Nos grupos HL, HPL e IL houve uma diminuição de mastócitos em ambos os períodos experimentais em relação aos grupos HS, HPS e IS, porém não se observou diferença estatística significativa entre o grupo HPS e o HPL aos oito dias. Conclusão: A laserterapia foi eficaz em modular a intensidade da resposta inflamatória induzida pelos medicamentos endodônticos a partir da redução significativa na quantidade de mastócitos. .

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O propósito deste estudo foi comparar a alteração dimensional linear de materiais de moldagem elastoméricos utilizados na transferência de posicionamento de implantes. Uma matriz metálica contendo dois implantes na região de caninos foi moldada com um silicone de adição, um poliéter, um silicone de condensação e uma mercaptana. Foram realizadas 10 moldagens e confecção de respectivos modelos, com os análogos em posição para cada material estudado. Os modelos obtidos foram mensurados na região inter-implantes em um microscópio e comparado com as distâncias mensuradas na matriz. As análises estatísticas e teste de Tukey indicaram que o poliéter e o silicone de adição são os materiais que menos sofreram alterações dimensionais, concluímos então que estes dois materiais são os mais indicados para a transferência do posicionamento de implantes.

The purpose of this study was to compare the linear dimensional accuracy of elastomericimpression materiais used in the transfer of placement of implants. A stainless still matrix containing two implants in the canine region was shaped with an addition silicone, a polyether, a condensation silicone and a polysulfide. Ten impressions were made and theirs respective casts models with the analogous ones in position for each kind of materiais studied. The obtained models were measured in the inter-implants region under a microscope and compared with the distances measured in the matrix. Statistical analysis and Tukey's test indicated that the polyether and addition silicone materiais that are less unchanged dimensional, then we conclude that these two materiais are most indicated for the transfer of the placement of implants.

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