A New Solution for the Removal of the Smear Layer

Journal of Endodontics, 2010

Introduction: Oval-shaped root canals might represent a great challenge for proper disinfection. This study compared the capability of a newly developed instrument, the self-adjusting file (SAF), and rotary nickeltitanium (NiTi) instrumentation to eliminate Enterococcus faecalis populations from long oval root canals of extracted human teeth. As a secondary purpose, the ability of a modification in sampling technique to recover bacteria lodged in recesses of oval canals was evaluated. Methods: Long oval canals from mandibular incisors and maxillary second premolars were infected with E. faecalis (ATCC 29212) for 30 days and then randomly distributed into 2 experimental groups. In group 1, canals were prepared up to a 40/04 rotary BioRaCe instrument by using irrigation with NaviTip needles; in group 2, canals were prepared by using the SAF system with continuous irrigation. NaOCl and ethylenediaminetetraacetic acid were used as irrigants. Bacteriologic samples were taken before (S1) and after preparation (S2a and S2b). Results: Reduction in the bacterial populations was highly significant in both groups (P < .001). Preparation of long oval canals with the SAF was significantly more effective than rotary NiTi instrumentation in reducing intracanal E. faecalis counts (P = .01). Frequency of positive cultures in S2 samples was 11 of 20 (55%) for rotary instrumentation and 4 of 20 (20%) for SAF instrumentation (P = .048). S2b samples (modified method) yielded more positive samples than S2a (12/40 vs 5/40), but this difference reached no statistical significance (P > .05). Conclusions: The SAF system was significantly more effective than rotary NiTi instrumentation used with syringe/needle irrigation in disinfecting long oval root canals in vitro. A modified sampling technique might be necessary for oval canals. (J Endod 2010;36:1860-1865

Clinical Oral Investigations

Objectives The impact of conservative instrumentation on the disinfection of root canals with different curvatures has not yet been determined. This ex vivo study aimed to evaluate and compare the effect of conservative instrumentation with TruNatomy (TN) and Rotate and a conventional rotary system, ProTaper Gold (PTG), on root canal disinfection during chemomechanical preparation of straight and curved canals. Materials and methods Ninety mandibular molars with straight (n = 45) and curved (n = 45) mesiobuccal root canals were contaminated with polymicrobial clinical samples. Teeth were divided into three subgroups (n = 14) according to the file systems and the curvature. Canals were instrumented with TN, Rotate, and PTG, respectively. Sodium hypochlorite and EDTA were used as irrigants. Intracanal samples were taken before (S1) and after (S2) instrumentation. Six uninfected teeth were used as negative controls. The bacterial reduction between S1 and S2 was measured by ATP assay, f...

The Alpha omegan, 2008

Australian Dental Journal, 2007

Chemomechanical preparation of the root canal includes both mechanical instrumentation and antibacterial irrigation, and is principally directed toward the elimination of micro-organisms from the root canal system. A variety of instruments and techniques have been developed and described for this critical stage of root canal treatment. Since their introduction in 1988, nickel-titanium (NiTi) rotary instruments have become a mainstay in clinical endodontics because of their exceptional ability to shape root canals with potentially fewer procedural complications. Safe clinical usage of NiTi instruments requires an understanding of basic metallurgy of the alloy including fracture mechanisms and their correlation to canal anatomy. This paper reviews the biologic principles of preparing root canals with an emphasis on correct use of current rotary NiTi instrumentation techniques and systems. The role and properties of contemporary root canal irrigants is also discussed.

Journal of Endodontics, 2011

Introduction: This study compared the ability of different approaches to supplement the antibacterial effects of chemomechanical preparation in ovalshaped root canals. Methods: Long oval canals from extracted teeth infected with Enterococcus faecalis (ATCC 29212) were chemomechanically prepared up to a 40/04 rotary BioRaCe instrument using 2.5% NaOCl irrigation and then subjected to two supplementary protocols. In the passive ultrasonic irrigation (PUI)/ chlorhexidine (CHX) group, canals were subjected to PUI for the activation of NaOCl followed by a final rinse with 0.2% CHX digluconate solution. In the Hedstr€ om group, canals received additional Hedstr€ om filing directed towards the buccal and lingual canal recesses. Bacteriological samples were taken before and after preparation, after PUI or Hedstr€ om instrumentation, and after CHX final rinsing. Results: Chemomechanical preparation and the supplementary steps promoted a highly significant bacterial reduction (P < .001). Quantitative (reduction in levels) and qualitative (frequency of negative cultures) analyses showed that PUI alone or Hedstr€ om filing did not significantly increase bacterial reduction (P > .05). Further rinsing with CHX also failed to significantly increase bacterial elimination when compared with post-PUI samples. However, the cumulative antibacterial effects of PUI and CHX final rinse were effective in significantly reducing bacterial counts to levels below those achieved after preparation (P = .03). This combined PUI/CHX approach also resulted in a significant increase in the incidence of negative cultures (P = .04). Conclusions: Findings suggest that there may be a benefit of using the PUI for the activation of NaOCl followed by a final rinse with CHX as supplementary steps in the treatment of infected oval-shaped root canals. (J Endod 2011;37:496-501)

Objectives: The aim of this in vitro study was to compare the efficacy of different irrigating solutions on root canal system and analyzing smear layer using scanning electron microscope (SEM). Materials and Methods: Fifty mandibular premolars were decoronated and split longitudinally. Each root half was divided into five groups (n = 10): Group I ‑ 3 ml of physiological saline, Group II ‑ 3 ml of 2.5% sodium hypochlorite (NaOCl), Group III ‑ 1 ml of 10% citric acid, Group IV ‑ 2% chlorhexidine (CHX) gluconate (Vishal Dentocare, India), Group V ‑ Largal Ultra (ethylenediaminetetraacetic acid [EDTA] 15% + cetrimide 0.75%), Septodont (Saint‑Maur‑des‑fosses, France), and Group VI ‑ Smear Clear (Sybron Endo, Orange, CA, USA) (17% EDTA, cetrimide, and a special surfactant). Irrigation regimens were performed for 1 min. The presence or absence of smear layer at the coronal, middle, and apical portion of each canal were examined under an SEM. Results: A significant difference (P < 0.001) in smear layer removal between smear clear and Largal Ultra at the apical and middle third of the canal was observed. The presence of debris is more obvious in the apical third rather than in the middle and coronal part of the root canals. Conclusion: Largal Ultra, Smear Clear, and the citric acid removed the smear layer more efficient way as compared to CHX, NaOCl, and saline solutions.

Journal of Endodontics, 1999

Journal of Forensic Medicine, 2020

Root canal treatment is a procedure done to remove the infected pulp of the tooth to prevent infection. Themost important step in root canal treatment is cleaning and shaping which is done to disinfect the root canal.Persistent microorganisms after root canal treatment, can lead to failure of the endodontic treatment. Surveyquestionnaires were prepared, using an online survey portal it was distributed randomly to 100 participantsvia social media application. Responses were tabulated and graphs were plotted. From the survey resultsit was evident that knowledge regarding the recent advancements of root canal disinfection is notable.There was no significant association between the field of practice (specialists / general practitioners) andtheir response to the questions. Overall, the survey showed a good knowledge and awareness among theresponders about the recent advancements in irrigants, used in the root canal treatment

World Journal of Dentistry

The success of an endodontic treatment involves cleaning and shaping, disinfection, and three-dimensional obturation of the root canal system. Thorough debridement of the root canal system of necrotic or infected pulp tissues, microorganisms, and complete sealing of the root canal space prevents the persistence of infection and reinfection of the root canal space. 1 Because of the complex anatomy of the root canal system, which includes lateral canals, ramifications, and deltas, it is impossible to completely disinfect the root canal using instrumentation alone. Irrigation is a critical complement to instrumentation because it removes bacteria, debris, and necrotic tissue present in the smear layer. 2 The literature also reports that the chemomechanical cleaning and shaping of the root canal greatly reduces the number of bacteria. 3,4 Root canal instrumentation produces a layer of inorganic and organic material called the smear layer. It comprises attached microbiota, their by-products, and toxins from root canal walls. It can prevent the penetration of intracanal medicaments into dentinal tubules and interfere with the close adaptation of root-filling materials to canal walls. 1 Therefore, removal of the smear layer is imperative for more thorough disinfection of the root canal system and better adaptation of materials to the canal walls. Chelating

Journal of Endodontics, 2001

The effect of tetracycline hydrochloride as an endodontic irrigant on smear layer removal was examined by scanning electron microscopy and compared with bidistilled water, 2.5% sodium hypochlorite (NaOCI), and 50% citric acid in 20 extracted teeth. Five teeth, as a control, were irrigated with bidistilled water only in group 1. All the other groups were irrigated with NaOCl during instrumentation. The final rinses were NaOCl in group 2, citric acid in group 3, and 1 % tetracycline hydrochloride in group 4. Scanning electron microscopic results and statistical analysis revealed that bidistilled water and NaOCl were ineffective in removing the smear layer, whereas citric acid and tetracycline hydrochloride were significantly more effective (p c 0.001). No statistically significant difference was detected between tetracycline hydrochloride and citric acid (p > 0.05). However tetra-