Avaliação da eficácia da desinfecção de instrumentos usados durante o período transoperatório do tratamento endodôntico / Evaluation of the desinfection efficacy of instruments used during the transoperatory period in endodontic treatment

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

10/01/2012

RESUMO

This investigation aimed to evaluate the antimicrobial efficacy of disinfectant agents used to maintain the disinfection of endodontic instruments during the transoperatory period in endodontic treatment. The antimicrobial activity of disinfectants isopropyl alcohol, acetone and peracetic acid were evaluated upon planktonic micro-organisms by time kill assay (contact test) using inoculums from 9,9 X 109 to 1,2 X 1012 colony forming units (CFU) and determination of minimal bactericidal concentration (MBC), using inoculums of 106 CFU. Chemical agents were also evaluated upon Enterococcus faecalis (E. faecalis) ATCC 29212 strain grown on matrix dentin (ex vivo) for biofilm formation. Biofilm (sessile organisms) were removed with Kerr files until the blades were visually filled and contaminated K files used as carriers (shortly after contamination or dried inside a flow chamber for 10 minutes). K files carriers were immersed in 80% isopropyl alcohol, 80% acetone or in 2% peracetic acid for 30 or 60 seconds. The files were subsequently dispensed into test tubes containing Enterococcosel broth to observe the growth of viable enterococci. Thereafter, in vivo experiments were performed with K files contaminated with pulp necrotic material from cervical region of teeth indicated to endodontic treatment. The contaminated K files were immersed for 30 or 60 seconds in 80% acetone, 80% isopropyl alcohol and 2% peracetic acid. The files were then inoculated into test tubes containing tioglycolate medium. The organisms that grew after peracetic acid treatment were identified. The corrosion mediated by the chemical agents was also tested after incubation of stainless steel and NiTi K files for 60 minutes, by measuring the weight of K-files before and after immersion, and by scanning electron microscopy (SEM). All chemical agents were capable to eliminate or reduce bacterial viability of planktonic Gram-negative and Gram-positive species, though the activity of chemicals upon sessile E. faecalis in K-file carrier tests demonstrated that isopropyl alcohol or acetone were incapable to eliminate bacterial contamination, especially when the files were dried previously to the exposition to the chemicals for 15 or 30 seconds. Peracetic acid demonstrated the best antimicrobial activity, and eliminated the viability of sessile E. faecalis cells from both wet and dried K-endodontic files after exposition for 15 seconds (100% elimination). The experiments developed in vivo demonstrated that peracetic acid was the most effective agent (p<0,05), capable of eliminating the viability of organisms in 92% of K files immersed after 60 seconds, when compared to acetone (64%) or isopropyl alcohol (50%). The microbial grown after contact with peracetic acid demonstrated that only Lactobacillus sp group was resistant to this chemical. The chemical agents demonstrated to be non-corrosive after immersion for 1 hour, by both weighing and SEM. The results indicated that peracetic acid was the most effective agent to be used as disinfectant of instruments during transoperatory period of endodontic treatment.

ASSUNTO(S)

acetona atividade antimicrobiana biofilmes tratamento odontológico desinfetantes Álcool isopropílico Ácido peracético endodontia canal radicular - tratamento desinfetantes de equipamento odontológico desinfecção e desinfetantes instrumentos odontológicos instrumentos e aparelhos odontológicos acetone antimicrobial activity biofilms dental therapy disinfectants isopropyl alcohol peracetic acid

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