Avaliação da microdureza e do potencial antimicrobiano de cimentos para cimentação modificados com diacetato de clorexidina a 0,5%

• Autor(a) principal: Oliveira, Henrique Eduardo
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14035
• topic: Cements; Chlorhexidine diacetate; Antimicrobian activity; Cytotoxic activity; Knoop microhardness test; Biocompatibility; Cimentos; Diacetato de clorexidina; Atividade antimicrobiana; Atividade citotóxica; Testes de microdureza Knoop; Biocompatibilidade; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

The aim of this study was to evaluate, in vitro, the hardness and the antimicrobial potential of three cements for cementation used in dentistry modified with 0.5% chlorhexidine diacetate. For the exhaustion test were used 48 specimens samples with 5 mm in diameter and 2 mm in height, placed in a 96 well plate, divided into 2 specimens samples according to the elution period for each previously determined group. The elution was done with PBS (phosphate buffer), making an isotonic environment for periods of 60, 30 and 15 days, or without exhaustion (immediate), with subsequent exposure to the bacterial inoculum (Streptococcus mutans in 80 Colony Forming Units - UFC) in an isotonic medium to prevent the death of bacteria. After 60 minutes at 37°C exposure, each specimen received 100 μL of agar TSA, for the analysis of the colonies growth. Cell viability was evaluated by colorimetric test Metiltetrazolium (MTT), which was used in a suspension of the cell type L929 (mouse fibroblasts gum), strain recommended by ISO 10993-5 2009 for carrying out the cytotoxicity tests. The samples were eluted in the periods of 24 hours, 72 hours and 7 days, when 200 μL were aliquoted from specimens samples eluting solution, to perform the colorimetric test. In general, four replicates were tested of each obtained samples, distributed into previously defined specimen groups, totalizing 18 specimens samples with a diameter of 5 mm and a height of 2 mm. The Knoop microhardness analysis (KHN) was done preparing five specimens samples for each experimental group with 5 mm in diameter and 2 mm in height, included in 6 pink acrylic resin blocks. Each group was designed according to the treatment to be received. Group 1 (G1) - Zinc phosphate cement without chlorhexidine diacetate; Group 2 (G2) - Ketac Cem Easymyx without clorexina diacetate; Group 3 (G3) - RelyX U 200 without chlorhexidine diacetate; Group 4 (G4) - Zinc phosphate cement with 0,5 % chlorhexidine diacetate; Group 5 (G5) - Ketac Cem EasyMix with 0,5% chlorhexidine diacetate; Group 6 (G6) - RelyX U 200 with 0,5% chlorhexidine diacetate. Regarding to exhaustion test, zinc phosphate cement showed the best antimicrobial activity. With regard to cytotoxicity, there was no significant cytotoxic effect of all tested samples, having only the zinc phosphate cement without adding chlorhexidine diacetate in the elution period of 72 h, stayed slightly above the cell viability bar. Considering the Knoop hardness, zinc phosphate cement showed less behavior than Ketac Cem Easymyx and RelyX U 200, which were not different between them. Thus, the addition of 0.5% chlorhexidine diacetate did not modified the mechanical property of the tested cements.