Effect of Passive Ultrasonic Irrigation on Enterococcus faecalis from Root Canals: An Ex Vivo Study

Abstract

Endodontic irrigation aims to clean and disinfect the root canal system. Passive ultrasonic irrigation (PUI) is based on the use of an ultrasound-activated instrument into the root canal filled with irrigant. The aim of this study was to evaluate, ex vivo, the effectiveness of PUI in eliminating Enterococcus faecalis from root canals. Seventy-five extracted human single-root teeth were used. After root canal preparation, specimens were inoculated with E. faecalis and incubated at 37 °C for 21 days. Specimens were distributed into five groups (n=15), according to the irrigation method: PUI + saline solution (PUI/SS); PUI + 1% NaOCl (PUI/NaOCl); conventional needle irrigation (CNI) + saline solution (CNI/SS); CNI + 1% NaOCl (CNI/NaOCl); No irrigation (control). Microbiological samples were collected at three time points: initial (21 days after inoculation), post-irrigation (immediately after irrigation), and final (7 days after irrigation). Data were obtained in CFU mL-1 and subjected to analysis by ANOVA and Tukey's tests at 5% significance level. The post-irrigation samples did not demonstrate statistical difference between PUI/SS and CNI/SS nor between PUI/NaOCl and CNI/NaOCl (p>0.05), but PUI/NaOCl and CNI/NaOCl had lower CFU mL-1 number than the other groups (p>0.05). Statistically significant difference was observed between the initial and post-irrigation samples and between the post-irrigation and final samples (p<0.05) in all groups, except in the control. The final samples of all groups presented bacterial counts similar to the initial samples. PUI or CNI with 1% NaOCl contribute to disinfection, but are unable to eradicate E. faecalis from the root canal system.

Efficacy of the photon‐initiated photoacoustic streaming combined with different solutions on Enterococcus faecalis in the root canals

“…Enhanced ATP assay kit can be used to detect the levels of ATP in common solutions, and different cells or tissues. Previous studies used paper points for sampling of bacteria from contaminated root canals (Guerreiro‐Tanomaru, Chavez‐Andrade, de Faria‐Junior, Watanabe, & Tanomaru‐Filho, ). Our study revealed no significant differences among the six subgroups in the CNI or LAI group after irrigation, and significantly greater reduction of ATP level in LAI than that in CNI ( p < .05), which is consistent with the results of a recent study that reported no significant differences in CFU value between the 3% NaOCl and CHX groups (Zhu et al, ).…”

Instrument Design May Influence Bacterial Reduction During Root Canal Preparation

“…The plate culture method was used in this study because of its simplicity and efficiency (5,7,(8)(9)(10)(11)(13)(14)(15)(16)(17)(18)(19). Molecular methods has been highlighted because of their high sensibility to detect microorganisms, but such a feature would not be necessary in this study as there was no total absence of bacterial growth in the collection.…”

“…However, it is known that the endodontic treatment is performed in association with chemical substances, which are aimed to assist instrumentation and enhance disinfection (5,13,15,22). Previous studies (17,22) observed that chemical substances used as irrigant have antimicrobial activity and reduce the bacterial number in the root canal, while other authors (23) confirmed that sodium hypochlorite penetrates into dentinal tubules, and found that bacteria on root canal surface and dentinal tubules were significantly reduced when the antimicrobial agents were used (18). Moreover, bacterial remaining was found at S2 and S3 collection, the chemical substances could reduce the bacterial amount.…”

Filling Material Removal with Reciprocating and Rotary Systems Associated with Passive Ultrasonic Irrigation

“…The impact caused by the phenomenon promotes smear layer removal, mainly in the areas where instruments cannot reach (19)(20)(21). Thus, it is valid to state that the same phenomenon may occur with the filling material (19,20).…”