Root Canal Microflora: Qualitative Changes after Endodontic Instrumentation

Abstract

The changes in the pattern of bacteria in root canal after repeated washing with NaOCl and endodontic instrumentation were evaluated. Samples were obtained from the root canals of patients before and after endodontic instrumentation, and analyzed according to the usual microbiological techniques. Washing with NaOCl and endodontic instrumentation act against bacteria such as Peptostreptococci, Streptococcus sanguis, Actinomyces israelii, Proteus mirabilis, Bacteroides, whereas Streptococcus lactis and Aerococcus were present before and after endodontic instrumentation. Environmental conditions such as low pH could be responsible for the persistence of gram-positive bacteria. The use of topical treatment and the associated endodontic instrumentation seem useful in the eradication of some bacteria in the root canal.

In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis

“…Enterococcus faecalis , a facultatively anaerobic Gram‐positive coccus, has been implicated in persistent root canal infections (Engström 1964, Cavalleri et al . 1989, Gomes et al .…”

Irradiation of infected root canals with a diode laser in vivo: Results of microbiological examinations

“…Cavalleri et al [5] succeeded in killing a large number of mainly gram-negative bacteria by repeated root canal irrigation with NaOCl. However, gram-positive bacteria, such as Streptococcus lactis and Aerococcus, persisted, probably because of environmental conditions such as acid pH.…”

Evaluation of time required for recontamination of coronally sealed canals medicated with calcium hydroxide and chlorhexidine

“…2002). Indeed, several studies have reported the failure of Ca(OH) 2 to eliminate enterococci effectively (Engström 1964, Cavalleri et al . 1989, Gomes et al .…”

“…The aim of combining Ca(OH) 2 and 2% chlorhexidine gel (CG) is to enhance antimicrobial effectiveness, particularly against resistant microorganisms such as Enterococcus faecalis that are implicated in the failure of root canal treatment (Engström 1964, Cavalleri et al . 1989, Gomes et al .…”

“…However, Ca(OH) 2 cannot be considered as a universal intracanal medicament, as it is not equally e¡ective against all bacteria found in the root canal (Gomes et al2002). Indeed, several studies have reported the failure of Ca(OH) 2 to eliminate enterococci e¡ectively (Engstro« m 1964, Cavalleri et al 1989, Gomes et al 1996c, Molander et al1998, Pinheiro et al 2003, as they tolerate high pH values, varying from 9 to 11.…”