Patterns of Enterococcus faecalis in infected root canals: An in vitro study
10.3969/j.issn.1671-167X.2009.06.017
- VernacularTitle:粪肠球菌在根管内定植模式的体外研究
- Author:
Huijie GUO
;
Lin YUE
- Publication Type:Journal Article
- Keywords:
Enterococcus faecalis;
,Dental pulp cavity;
Periapical periodontitis;
Dental models
- From:
Journal of Peking University(Health Sciences)
2009;41(6):699-701
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To establish an in vitro root canal model infected by Enterococcus faecalis and to observe the morphology, distribution and relative position of Enterococcus faecalis in infected root canals.Methods: Ten human healthy premolars extracted for orthodontic reasons were collected. Following sterilization , a total of 5 specimens were aseptically transferred to separate Eppendorf tubes containing 1. 5 mL brain-heart infusion broth (BHI) inoculated with 0.1 mL Enterococcus faecalis suspension that had been adjusted to Mcfarland 5, and were incubated at 37℃ for 21 days. The other 5 specimens were as controls. The roots of all specimens were then split into two halves along the mesiodistal axis. One half was processed with light microscopic ( Brown & Brenn stain) to check the bacteria in dentinal tubules, and the other was observed with SEM to investigate the bacterial status in infected root canals. Results: Enterococcus faecalis could penetrate into the dentinal tubules about 330-1 000μm. A dense bacterial aggregation composed of Enterococcus faecalis and amorphous matrix was observed in the apical third of the root canals, whereas Enterococcus faecalis were seen free-floating or planktonic in the crown and middle third of the root canals . No microorganisms were found in the root canals of the controls. Conclusion:Enterococcus faecalis could form bacterial biofilm on the root canal walls and penetrate into the dentinal tubules. The in vitro model designed was simple, and had good practicability to make a further comparative evaluation of various antimicrobial methods in the reduction of intracanal bacteria.
