Guedes-Pinto paste is the filling material most employed in Brazil for endodontic treatment of deciduous teeth; however, the Rifocort® ointment has been removed. Thus, the aim of this study was to investigate the antimicrobial potential of filling pastes, by proposing three new pharmacological associations to replace Rifocort® ointment with drugs of already established antimicrobial power: Nebacetin® ointment, 2% Chlorhexidine Gluconate gel, and Maxitrol® ointment. A paste composed of Iodoform, Rifocort® ointment and Camphorated Paramonochlorophenol (CPC) was employed as the gold standard (G1). The other associations were: Iodoform, Nebacetin® ointment and CPC (G2); Iodoform, 2% Chlorhexidine Digluconate gel and CPC (G3); Iodoform, Maxitrol® ointment and CPC (G4). The associations were tested for Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), Enterococcus faecalis (E. faecalis), Escherichia coli (E. coli), and Bacillus subtilis (B. subtilis), using the methods of dilution on solid medium – orifice agar – and broth dilution. The results were tested using statistical analysis ANOVA and Kruskal-Wallis. They showed that all the pastes had a bacteriostatic effect on all the microorganisms, without any statistically significant difference, compared with G1. S. aureus was statistically significant (multiple comparison test of Tukey), insofar as G2 and G3 presented the worst and the best performance, respectively. All associations were bactericidal for E. coli, S. aureus, S. mutans and S. oralis. Only G3 and G4 were bactericidal for E. faecalis, whereas no product was bactericidal for B. subtilis. Thus, the tested pastes have antimicrobial potential and have proved acceptable for endodontic treatment of primary teeth.

OBJETIVO: Este estudo avaliou a ação antimicrobiana de pastas, uma à base de iodofórmio conhecida por Pasta Guedes-Pinto (PGP) e outra modificada pela adição de digluconato de clorexidina (CHX) a 2% em substituição ao paramonoclorofenol canforado da formulação original da PGP. METODOLOGIA: A ação antimicrobiana das duas pastas foi testada contra Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus oralis, Enterococcus faecalis, Escherichia coli e Bacillus subtilis. O método empregado foi o de Diluição em Meio Sólido, Difusão em Ágar. Dezoito placas de Petri com 20 mL de BHIA foram inoculados com 0,1 mL das suspensões microbianas. Discos de papel foram imersos nas soluções experimentais por 1 min e colocados sobre a superfície de BHIA em cada placa. As placas foram mantidas em temperatura ambiente por 1 h e então incubadas a 37ºC por 48 h. O diâmetro da inibição microbiana foi medida ao redor dos discos de papel. Os dados foram pelo teste U de Mann-Whitney (α=0,05). RESULTADOS: A PGP teve ação bacteriostática contra todos os microrganismos e também bactericida exceto para Enterococcus faecalis e Bacillus subtilis. A CHX apresentou ação bacteriostática e bactericida contra todos os microrganismos. Não houve diferença estatística significante quanto à efetividade antimicrobiana entre as pastas avaliadas. CONCLUSÃO: Ambas as pastas apresentaram ação antimicrobiana contra quase todos os microrganismos encontrados em infecções endodônticas de dentes decíduos.

PURPOSE: This study assessed the antimicrobial effectiveness of an iodoform-based paste (Guedes-Pinto Paste, GPP) and a paste modified by the addition of a 2% chlorhexidine gluconate gel (CHX) to replace the camphorated parachlorophenol component of the original GPP. METHODS: The antimicrobial action was tested against the following microorganisms: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus oralis, Enterococcus faecalis, Escherichia coli and Bacillus subtilis. In the agar diffusion test, 18 Petri plates with 20 mL of BHIA were inoculated with 0.1 mL of the microbial suspensions. Paper disks were immersed in the experimental solutions for 1 min and were then placed over the BHIA surface in each agar plate. The plates were maintained for 1 h at room temperature and then incubated at 37ºC for 48 h. The diameters of the microbial inhibition halos were measured around the paper disks containing the substances. Data were analyzed using the Mann-Whitney U-test (α=0.05). RESULTS: Antimicrobial action was observed for the GPP and CHX pastes, which presented absence of turbidity for almost all microorganisms. No statistically significant difference in the antimicrobial action was found between GPP and CHX. CONCLUSION: Both pastes present similar antimicrobial effectiveness against several microorganisms commonly found in endodontic infections in deciduous teeth.