Antibacterial activity of intracanal medications based on calcium hydroxide and zinc oxide micro- or nanoparticles: an ex vivo study

AbstractIntroduction Nanoparticles and associations to calcium hydroxide can be used to increase antimicrobial activity.Objective To evaluate antibacterial activity against Enterococcus faecalis and pH of intracanal medications (IM) based on calcium hydroxide (CH) and zinc oxide (ZnO) micro- or nanoparticles, and their association with 0.4% chlorhexidine (CHX).Material and method Root canals from single-rooted human teeth were inoculated and incubated for 21 days. After sample (S1), the root canals were filled with the medications for 7 days and samples were collected immediately after medication (S2) and 7 days later (S3). Counting of CFU mL-1 was performed. Polyethylene tubes filled with the medications were used for the pH evaluation after 3, 7, 14 and 28 days. Data were submitted to ANOVA and Tukey tests (p<0.05).Result All IM promoted elimination of E. faecalis immediately after medication (S2). All the pastes promoted a similar pH increase.Conclusion CH/ZnO micro- or nanoparticles associated with CHX promoted greater bacterial reduction in the root canals and similar pH.

Abstract (portuguese)

ResumoIntrodução Nanopartículas e associações ao hidróxido de cálcio podem ser usados para aumentar a ação antimicrobiana.Objetivo Avaliar a atividade antibacteriana sobre Enterococcus faecalis e o pH de medicações intracanal (MI) à base de hidróxido de cálcio (HC) e óxido de zinco (OZn) micro- e nanoparticulado, e suas associações com clorexidina (CHX) a 0,4%.Material e método Canais radiculares de dentes humanos unirradiculados foram inoculados e incubados por 21 dias. Após coleta (C1), os canais radiculares foram preenchidos com os medicamentos durante 7 dias e as amostras foram coletadas imediatamente após a medicação (C2) e 7 dias depois (C3). Contagem de UFC mL-1 foi realizada. Os tubos de polietileno preenchidos com os medicamentos foram utilizados para a avaliação do pH após 3, 7, 14 e 28 dias. Os dados foram submetidos aos testes de ANOVA e Tukey (p<0,05).Resultado Todas as MI promoveram eliminação de E. faecalis imediatamente após a medicação (C2). Todas as pastas promoveram similar aumento de pH.Conclusão HC/OZn micro- ou nanoparticulado associado com CHX promove maior redução bacteriana nos canais radiculares e pH similar.