Bacteriological Evaluation of Passive Ultrasonic Activation

doi:10.1097/00004770-200301000-00004

Journal of Endodontics

Volume 29, Issue 1, January 2003, Pages 12-14

https://doi.org/10.1097/00004770-200301000-00004 Get rights and content

The purpose of this study was to evaluate the influence of passive ultrasonic activation on root canal disinfection. Sixty human teeth (group A: upper incisors, group B: upper canines, and group C: distobuccal root of first upper molars) were selected and sterilized in an autoclave. A standardized inoculum was placed into the canals, and they were incubated for 72 h at 37°C. Then, they were divided into subgroup 1, which received sterile saline (SS) as an irrigant, and subgroup 2, which received sterile saline with passive ultrasonic activation (SU). The endodontic treatment was performed with a crown-down technique. Bacteriological identification of surviving colonies was carried out.

Surviving colonies were higher when ultrasonics was not used (group A: SS:

32.13, SU:

13.53; group B: SS:

53.70, SU:

44.60; group C: SS:

39.16, SU:

29.40). The homogeneity proportion tests to compare the results of both subgroups showed that the surviving proportions were higher (p = 0.01) when the ultrasonic activation was not used.

Section snippets

MATERIAL AND METHODS

A representative sample of teeth, regardless of age and gender of the patient, with different root canal anatomy were selected after vitality diagnosis. They were upper incisors, upper canines, and first upper molars that were extracted for periodontal reasons. Only the distobuccal root of the first upper molar was involved in this work.

The teeth were sterilized in an autoclave according to the Centers for Disease Control and Prevention standards (⁷) and the proposals of Tate and White (⁸)

RESULTS

Surviving colonies were observed in all the teeth of the sample. In one upper canine, the development of contaminant bacillus was observed, probably due to a technical error. The number of surviving colonies was lower when ultrasonic activation was used (Table 1).

‡ A: central upper incisors; B: upper canines; C: distobuccal root first upper molar.

§: contaminated.

*: Subgroup 1: sterile saline; subgroup 2: sterile saline + ultrasonics.

The proportion of contaminated canines was significantly

DISCUSSION

When sterile saline was ultrasonic activated, there were less surviving bacteria. Ultrasound seems to improve the disinfection of infected root canals, probably because organic tissues entering the streaming field generated by ultrasound are disrupted, as proposed by Walmsley (⁹).

The teeth that had more surviving colonies were the upper canines, probably due to the complexity of the pulpal cavity. In addition, a general problem with all rotary techniques is their inability to form round

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Cited by (40)

Evaluation of various irrigation activation systems to eliminate bacteria from the root canal system: A randomized controlled single blinded trial
2020, Journal of Dentistry
To evaluate the effect of NaOCl irrigant activation using passive ultrasonic activation, F-files, XP-endo Finisher files and or needle irrigation alone on the reduction of intracanal bacteria from root canals in teeth undergoing root canal treatment.
Eighty patients with asymptomatic apical periodontitis were randomly divided into four groups. Access cavities were prepared and pre-treatment samples were taken (S1). Canals were then prepared and post-instrumentation samples (S2) taken. NaOCl was then activated with the various irrigant activation systems and post-irrigation samples (S3) taken. The samples were processed and colony forming units (CFUs) of bacteria were determined. The reduction in CFUs among the experimental groups were analysed using the Kruskal Wallis test and pairwise comparisons with the Mann-Whitney test. The Friedman test was used to compare the differences in the reduction of CFUs within the groups.
Overall, for all groups there was a significant reduction in the CFUs from S1 to S2 (P < 0.05) and from S2 to S3 (P < 0.05). Both XP-endo Finisher and passive ultrasonic activation techniques were associated with the greatest reduction in CFUs with no significant difference between them (P = 0.24). However, both were associated with significantly lower CFUs when compared to F-file activation and needle irrigation (P < 0.05). F-file activation reduced the CFUs significantly more compared to needle irrigation (P = 0.04).
XP-endo Finisher file activation and passive ultrasonic activation were equivalent in terms of reduction in CFUs. F-file activation did not reduce the CFUs to the same extent as the XP-endo Finisher file and ultrasonic activation but reduced the CFUs more than needle irrigation.
The present study highlights the effect of new XP-endo Finisher file and passive ultrasonic activation in reducing the bacterial load from the root canal system which is important for the success of root canal treatment.
Ultrasonic Irrigant Activation during Root Canal Treatment: A Systematic Review
2019, Journal of Endodontics
Citation Excerpt :
The age of the teeth (donors) was unknown in all but 1 of the studies on the antimicrobial effect of the irrigation methods (35); this parameter determines the amount of sclerotic dentin (68) and could have affected the infection/disinfection procedures (69). Six studies did not describe random allocation of the specimens to the different groups (21, 23, 26, 27, 34, 48), so their findings may have been affected by selection bias. Furthermore, 6 studies tried to establish baseline equality of the compared groups after randomization by statistical testing of preoperative anatomic parameters (20, 40, 41, 43, 63, 65), an approach of questionable validity (70, 71).
The aim of this study was to systematically review the evidence on the cleaning and disinfection of root canals and the healing of apical periodontitis when ultrasonic irrigant activation is applied during primary root canal treatment of mature permanent teeth compared with syringe irrigation.
An electronic search was conducted of the Cochrane Library, Embase, LILACS, PubMed, SciELO, and Scopus databases using both free-text key words and controlled vocabulary. Additional studies were sought through hand searching of endodontic journals and textbooks. The retrieved studies were screened by 2 reviewers according to predefined criteria. The included studies were critically appraised, and the extracted data were arranged in tables.
The electronic and hand search retrieved 1966 titles. Three clinical studies and 45 in vitro studies were included in this review. Ultrasonic activation did not improve the healing rate of apical periodontitis compared with syringe irrigation after primary root canal treatment of teeth with a single root canal. Conflicting results were reported by the in vitro microbiological studies. Ultrasonic activation was more effective than syringe irrigation in the removal of pulp tissue remnants and hard tissue debris based on both clinical and in vitro studies. Ultrasonic activation groups were possibly favored in 13 studies, whereas syringe irrigation groups may have been favored in 3 studies.
The level of the available evidence was low, so no strong clinical recommendations could be formulated. Future studies should focus on the antimicrobial effect and healing of apical periodontitis in teeth with multiple root canals.
In Vitro Efficacy of XP-endo Finisher with 2 Different Protocols on Biofilm Removal from Apical Root Canals
2017, Journal of Endodontics
The purpose of this study was to evaluate the effectiveness of the XP-endo Finisher (XPF; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) in biofilm removal in comparison with conventional needle irrigation (CNI) and passive ultrasonic irrigation (PUI) using an infected tooth model with an artificial apical groove.
Fifty-four extracted human single-rooted premolars were selected. Each tooth was split longitudinally into 2 halves, with a groove made in the apical segment of the canal wall. After growing mixed bacteria biofilm for 4 weeks, the split halves were reassembled and instrumented using Vortex Blue files (Dentsply Tulsa Dental, Tulsa, OK) to size 40/.06. The instrumented teeth were randomly assigned to 6 groups (n = 8) according to the final irrigation protocol. Three different techniques (CNI, PUI, and XPF) were performed each with either continuous irrigation or 3-step irrigation. Scanning electron microscopic images were taken to evaluate the amount of residual biofilm inside and outside the groove.
Robust growth of biofilm was observed in each canal of the controls after 4 weeks. XPF showed the best biofilm removal efficacy inside and outside the groove followed by PUI and CNI (P < .05). The XPF 2 group using the 3-step protocol showed better antibiofilm efficiency than the XPF 1 group with continuous irrigation inside the groove (P < .05).
The XP-endo Finisher, as an irrigation agitation technique, may help to remove biofilm from hard-to-reach areas in the root canal system. The 3-step irrigation protocol was more effective than continuous irrigation when XPF was used.
MTAD combined with endosonic irrigation as a new approach for the disinfection of Enterococcus faecalis biofilm
2015, Journal of Dental Sciences
Citation Excerpt :
Although it has been suggested that adding 1.3% NaOCl could promote the antimicrobial activity of MTAD,7 there is still controversy on the antimicrobial efficacy of 1.3% NaOCl/MTAD versus 5.25% NaOCl/15% EDTA.8 Traditionally, irrigants are delivered using needles, which have been reported to inadequately remove the smear layer and incompletely disrupt biofilms from the canal wall.9,10 Mechanical agitation has been shown to improve the removal of the smear layer and increase the antimicrobial effects of irrigants.
Enterococcus faecalis plays a major role in continuing refractory apical periodontitis. The purpose of this study was to investigate the antibacterial effects of sodium hypochlorite (NaOCl) combined with MTAD [a mixture of tetracycline isomer (doxycycline), an acid (citric acid), and a detergent (Tween 80)] as an endosonic irrigation protocol against E. faecalis biofilm.
The dentin blocks were incubated with E. faecalis and randomly assigned to five irrigation groups (n = 10): MTAD, 1.3% NaOCl with MTAD, 1.3% NaOCl, 5.3% NaOCl, and 5.3% NaOCl with 17% EDTA using Endoactivator oscillation for 30 seconds and 1 minute, respectively; saline without agitation as a control. The bacterial samples were measured by colony-forming counting. The percentage of viable cells and the thickness of the biofilms were evaluated using confocal laser scanning microscopy. Specimens were observed via scanning electron microscopy.
When Endoactivator was applied for 30 seconds, viable counting of the 5.3% NaOCl/17% EDTA group and 1.3% NaOCl/MTAD group were lower than the MTAD group (P < 0.05), whereas the differences between the former two are not significant. There were no statistically significant differences in the number of colony-forming counting unit between 30 seconds and 60 seconds (P > 0.05). The 1.3% NaOCl/MTAD group and the MTAD group appeared to preserve the structure of the dentin surface and cause efficient removal of the smear layer.
Endoactivator could improve the synergistic antimicrobial action of 1.3% NaOCl and MTAD against E. faecalis biofilm and removal of the smear layer with less erosion of the dentin surface. The combination could be a safe and efficient irrigation regimen.
Fluid dynamics and biofilm removal generated by syringe-delivered and 2 ultrasonic-assisted irrigation methods: A novel experimental approach
2015, Journal of Endodontics
Thorough understanding of fluid dynamics in root canal irrigation and corresponding antibiofilm capacity will support improved disinfection strategies. This study aimed to develop a standardized, simulated root canal model that allows real-time analysis of fluid/irrigation dynamics and its correlation with biofilm elimination.
A maxillary incisor with an instrumented root canal was imaged with micro–computed tomography. The canal volume was reconstructed in 3 dimensions and replicated in soft lithography-based models microfabricated from polyethylene glycol–modified polydimethylsiloxane. Canals were irrigated by using a syringe (SI) and 2 ultrasonic-assisted methods, intermittent (IUAI) and continuous (CUAI). Real-time fluid movement within the apical 3 mm of canals was imaged by using microparticle image velocimetry. In similar models, canals were inoculated with Enterococcus faecalis to grow 3-week-old biofilms. Biofilm reduction by irrigation with SI, CUAI, and IUAI was assessed by using a crystal violet assay and compared with an untreated control.
SI generated higher velocity and shear stress in the apical 1–2 mm than 0–1 and 2–3 mm. IUAI generated consistently low shear stress in the apical 3 mm. CUAI generated consistently high levels of velocity and shear stress; it was the highest of the groups in the apical 0–1 and 2–3 mm. Biofilm was significantly reduced compared with the control only by CUAI (two-sample permutation test, P = .005).
CUAI exhibited the highest mechanical effects of fluid flow in the apical 3 mm, which correlated with significant biofilm reduction. The soft lithography-based models provided a novel model/method for study of correlations between fluid dynamics and the antibiofilm capacity of root canal irrigation methods.
Photodynamic therapy versus ultrasonic irrigation: Interaction with endodontic microbial biofilm, an ex vivo study
2014, Photodiagnosis and Photodynamic Therapy
Citation Excerpt :
There is no one unique irrigant that can possess all required criteria for the best root canal disinfection, so dual irrigant protocols using NaOCl and EDTA solutions are mainly used in Endodontics [20–22]. The use of ultrasonic devices during irrigation has been proposed to confront the problems observed during cleaning and disinfection of the root canal system [22] and the results are significant in reducing survival bacteria [23,24]. Passive ultrasonic irrigation (PUI) seems to enhance theses results [19], due to an acoustic streaming into the root canal [23].
Photodynamic therapy was introduced as an adjuvant to conventional chemo-mechanical debridement during endodontic treatment to overcome the persistence of biofilms. The aim of this study was to evaluate the ability of photodynamic therapy (PDT) to disrupt an experimental microbial biofilm inside the root canal in a clinically applicable working time.
Thirty extracted teeth were prepared and then divided in three groups. All samples were infected with an artificially formed biofilm made of Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis and Prevotella intermedia bacteria. First group was treated with Aseptim Plus® photo-activated (LED) disinfection system, second group by a 650 nm Diode Laser and Toluidine blue as photosensitizer, and the third group, as control group, by ultrasonic irrigation (PUI) using EDTA 17% and NaOCl 2.6% solutions. The working time for all three groups was fixed at 3 min. Presence or absence of biofilm was assessed by aerobic and anaerobic cultures.
There was no statistically significant difference between results obtained from groups treated by Aseptim Plus® and Diode Laser (P < 0.6267). In cultures of both groups there was a maximal bacterial growth. The group that was treated by ultrasonic irrigation and NaOCl and EDTA solutions had the best results (P < 0.0001): there was a statistically significant reduction of bacterial load and destruction of microbial biofilm.
Under the condition of this study, Photodynamic therapy could not disrupt endodontic artificial microbial biofilm and could not inhibit bacterial growth in a clinically favorable working time.

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SCIENTIFIC ARTICLESBacteriological Evaluation of Passive Ultrasonic Activation

Section snippets

MATERIAL AND METHODS

RESULTS

DISCUSSION

Oral Surg Oral Med Oral Pathol

J Endodon

J Endodon

J Endodon

J Endodon

Changing concepts in endodontic therapy

J Am Dent Assoc

SCIENTIFIC ARTICLES
Bacteriological Evaluation of Passive Ultrasonic Activation