In vitro evaluation of endodontic debris removal as obtained by rotary instrumentation coupled with ultrasonic irrigation

Histological evaluation of the debris removal efficiency of activation of sodium hypochlorite solution at different concentrations

BACKGROUND

This study aims to histologically evaluate the efficiency of debris removal through activation of 2.5% and 5.25% NaOCI using laser, ultrasonic, and intracanal heating methods.

METHODS

Sixty-four maxillary central incisor teeth were randomly divided into two groups according to the irrigation solution (n = 32); 2.5% NaOCI and 5.25% NaOCI. Subsequently, the samples were further divided into four subgroups according to the final irrigation activation technique (n = 8); SubgroupA: Er,Cs:YSGG laser, SubgroupB: Ultrasonic, Subgroup C: Intracanal heating, Subgroup D: no activation. Generalized Linear Models and Bonferroni tests were used for statistical analysis (p < 0.05).

RESULTS

The effect of NaOCI concentration was statistically significant (p < 0.001). Furthermore, the activation of NaOCI by laser exhibited a statistically significant difference compared to the ultrasonic and intracanal heating methods (p < 0.001).

CONCLUSION

The efficiency of root canal cleaning increases with higher NaOCI concentration. Activation of NaOCI also significantly enhances its effectiveness.

Effect of Chemical Debridement and Irrigant Activation on Endodontic Treatment Outcomes: An Updated Overview

Chemical debridement is considered one of the most important steps during root canal treatment to target unreached areas and provide thorough disinfection of the canals. The efficiency of this step efficiency can be increased using different agitation and irrigation techniques/devices. This comprehensive review aimed to summarize the effect of various irrigant activation and agitation techniques/devices on endodontic treatment outcomes. Using mechanical active irrigation, which enables the activation or agitation of the irrigating solution, is beneficial in root canal treatment by increasing the efficiency of delivering the irrigant up to working length and ensuring isthmus cleanliness. However, considerable variation was noticed between the protocols used in each technique with a lack of well-designed randomized clinical trials to focus on the long-term outcome. Moreover, a low level of evidence was noticed regarding the effectiveness of certain activation techniques over others. Therefore, each study needs to be carefully weighed before using its results and embracing its conclusion. Future studies need to focus more on the antimicrobial effect of each technique and its effect on the healing of apical periodontitis. Also, recent advances, such as multisonic and laser activation, are promising tools that need more clinical investigations to show their efficiency.

Novel laser activated photoacoustic streaming for removing pulp remnants from round root canals after single file reciprocating instrumentation: Photoacoustic streaming for removing pulp

BACKGROUND

This study evaluated the efficacy of a new laser-assisted irrigation system, the shock wave enhanced emission photo-acoustic streaming (SWEEPS) technique in removing pulp tissue from single-rooted premolars.

METHODS

Freshly extracted mandibular premolars with round root canals (n=40), scanned using cone beam computed tomography, were randomly divided into control and four experimental (according to the irrigation technique used) groups (n=8/group). Groups 1, 2, and 3 were instrumented using Reciproc Blue (RB25/.06) followed by final irrigation protocol (FIP), activated by SWEEPS, ultrasonically activated irrigation (UAI), and conventional irrigation (CI), respectively. In these groups, 7 mL 3% NaOCl in total was used during instrumentation; for FIP, 3% NaOCl (60 s), ethylenediaminotetraacetic acid (60s), and 3% NaOCl (30s). In group 4, SWEEPS activation of 3% NaOCl for 6 × 30 s alone was performed. The untreated control group specimens were processed for histological evaluation of remaining pulp tissue (RPT) in each canal third. The results were analyzed using the Mann-Whitney U test (α =0.05).

RESULTS

Significant differences were observed between the control group and the experimental groups (p<0.05). In the middle third, the UIA and SWEEPS showed similar efficacy (p=0.171), superior to CI and SWEEPS without instrumentation (p<0.05). In the apical third, SWEEPS was the most efficient (p=0.002), and UIA and CI showed no difference (p=0.643).

CONCLUSION

SWEEPS was superior to UIA and CI in removing RPT in the apical region of round canals after single instrument root canal preparation; SWEEPS without instrumentation was inefficient in removing pulp tissue.

Effect of ultrasonic activation of photosensitizer dye temoporfin (Foscan) on antimicrobial photodynamic therapy: An ex vivo study

Aim:

The aim of this study is to evaluate the effectiveness of ultrasonic activation of photosensitizer (PS) drug Foscan in the elimination of endodontic pathogen from root canal system.

Materials and Methods:

The minimal bactericidal concentration of “Foscan” was determined using disc diffusion and broth dilution method. Forty-eight extracted single-rooted premolars with periapical pathology were used for the study. After access opening, the first microbial sample was taken. The teeth were then randomly divided into four groups: Group 1: Chemomechanical debridement (CMD), Group 2: CMD and passive ultrasonic irrigation (CMD + PUI), Group 3: CMD and antimicrobial photodynamic therapy (aPDT), and Group 4: CMD and aPDT with activation by ultrasonics. After antimicrobial protocols, the second microbiological sample was collected. The samples were analyzed by multiplex polymerase chain reaction for the effectiveness of four antimicrobial protocols on Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, and Treponema denticola.

Statistical Analysis Used:

Wilcoxon signed-rank test and Mann–Whitney U-test with the significant level P < 0.05, using IBM SPSS statistics 20 version software.

Results:

Foscan at concentration of 3.125 μg/ml was chosen for antimicrobial analysis. The prevalence of T. denticola, F. nucleatum, P. gingivalis, and P. intermedia was 79.17%, 70.84%, 70.83%, and 58.33%, respectively. Group 4 showed highest bacterial reduction of 99.51%, followed by Group 1 which showed bacterial reduction of 97.35%.

Conclusions:

Foscan can be used as an effective PS dye at low concentration with minimal tendency for tooth discoloration. Ultrasonic activation of PS dye facilitated better diffusion into dentinal tubules and biofilm obtaining greater bacterial reduction.

Radiographic evaluation of root canal cleaning, main and laterals, using different methods of final irrigation

OBJECTIVE: To evaluate the efficacy of passive ultrasonic irrigation (PUI) using intermittent or continuous flushing and conventional manual irrigation (CMI) on the cleaning of main and simulated lateral root canals.MATERIAL AND METHOD: The root canals of 24 artificial teeth were prepared and simulated lateral canals were made in the medium and apical thirds of the root. The specimens were divided into three groups: G1- CMI, G2- PUI 1 (intermittent flushing) and G3- PUI 2 (continuous flushing). Root canals were filled with contrast solution and the roots were radiographed pre- and post-irrigation. The digital images were transferred to Image Tool 3.0 software and the areas of root canal completely filled with contrast, and after irrigation with contrast remnant, were measured to obtain percentage data. Statistical analysis between groups was performed by ANOVA and Tukey tests.RESULT: In the apical third, G2 and G3 (PUI) groups showed higher percentage of cleaning than G1 (CMI) (p<0.05).CONCLUSION: Passive ultrasonic irrigation using intermittent flushing promoted a higher cleaning of simulated lateral canals than conventional manual irrigation in the apical third. There were no differences between groups in the main root canal and the middle third.

Endodontic treatment of hypertaurodontism with multiple bilateral taurodontism

The term taurodontism is derived from the Latin word tauros, for “bull,” and the Greek term odus, for “tooth,” or “bull tooth.” Taurodontism is a morpho-anatomical developmental anomaly, which is seen infrequently in teeth only. It is characterized by a deficiency in the constriction at the cement-enamel junction, with lengthened pulp chambers and apical displacement of the pulpal floor. This gives the tooth a quadrilateral or cylindrical look. This report presents a case of multiple bilateral taurodontism and the successful endodontic treatment of the tooth that had hypertaurodontism. A male patient was referred to the endodontic clinic with decayed left maxillary first molar. Hypertaurodontism was confirmed after clinical and radiographic examination. Panaromic X-rays revealed that all of the patient's molar teeth were taurodontic. Taurodontism offers challenges to the practitioner during shaping and disinfection and at the time of filling the root canals.

Cleaning capacity promoted by motor-driven or manual instrumentation using ProTaper Universal system: Histological analysis

Aim:

The aim of this study was to assess the cleaning capacity of the Protaper system using motor-driven or manual instrumentation.

Materials and Methods:

Ten mandibular molars were randomly separated into 2 groups (n = 5) according to the type of instrumentation performed, as follows: Group 1 - instrumentation with rotary nickel-titanium (Ni-Ti) files using ProTaper Universal System (Dentsply/Maillefer); and, Group 2 - instrumentation with Ni-Ti hand files using ProTaper Universal (Dentsply-Maillefer). Afterwards, the teeth were sectioned transversely and submitted to histotechnical processing to obtain histological sections for microscopic evaluation. The images were analyzed by the Corel Photo-Paint X5 program (Corel Corporation) using an integration grid superimposed on the image.

Results:

Statistical analysis (U-Mann-Whitney - P < 0.05) demonstrated that G1 presented higher cleaning capacity when compared to G2.

Conclusions:

The rotary technique presented better cleaning results in the apical third of the root canal system when compared to the manual technique.

Morphometrical analysis of cleaning capacity of a hybrid instrumentation in mesial flattened root canals

The cleaning capacity of hybrid and rotary instrumentation techniques in mesial flattened canals of mandibular first molars was evaluated by morphometrical analysis in this study. Twenty human mandibular first molars were randomly assigned into two groups, according to instrumentation technique, as follows: group 1, instrumentation with ProTaper Starter Kit (Dentsply/Maillefer) rotary system; group 2, manual instrumentation using K files (Dentsply/Maillefer) by crown-down technique in middle and apical thirds, cervical preparation with Gates-Glidden #1 and #2 (Dentsply/Maillefer) burs, and to finalise the preparation, ProTaper F2 and F3 rotary files. Serial transverse cross-sections (5 µm) of the apical third, stained with hematoxylin and eosin, were analysed at 100× original magnification. The images were submitted to morphometrical analysis with an integration grid to determine the percentage of root canal area with debris. Statiscal analysis (t-Student, P < 0.05) showed significant difference between the techniques (P < 0.05), although neither completely cleaned the root canal.

Indications for surgical endodontics and findings of an audit into referrals

Peri-radicular surgery is a valuable treatment modality allowing thorough treatment of chronic infection of the peri-radicular tissues. It is important that this treatment option is prescribed appropriately and steps are taken to help improve outcomes of surgery. We discuss the indications for peri-radicular surgery, considerations when planning treatment for teeth where orthograde endodontics has failed and present the findings of an audit into the appropriateness of referrals for peri-radicular surgery to the Department of Oral and Maxillofacial Surgery at a District General Hospital.

CLINICAL RELEVANCE

This article highlights the indications and contra-indications for peri-radicular surgery to general dental practitioners.

Effect of ultrasonication with EDTA or MTAD on smear layer, debris and erosion scores

The purpose of this study was to compare the effects of ultrasonication with ethylenediaminetetraacetic acid (EDTA) and a mixture of tetracycline isomer, an acid, and a detergent (MTAD) as final canal irrigants on the smear layer, debris and erosion scores. Fifty-eight extracted single-rooted human teeth were instrumented with ProTaper rotary files up to size F3. According to the final irrigation regimen, the samples were distributed into the following groups: EDTA, MTAD, EDTA ultrasonicated for 1 min, and MTAD ultrasonicated for 1 min. The smear layer, debris and erosion scores were recorded at the apical, middle, and coronal third of each canal using a scanning electron microscope. Data were subjected to statistical evaluation using the Kruskal-Wallis and Mann-Whitney tests (P < 0.05). There were no significant differences in smear layer or debris removal between the experimental groups. EDTA caused significantly more erosion at the middle level than MTAD. Also EDTA resulted in more erosion at the coronal level than MTAD when subjected to ultrasonication. Ultrasonic activation of EDTA significantly increased its erosive effects at the middle and coronal levels. Based on the present findings, MTAD appears to cause less dentinal erosion while allowing proper removal of the smear layer and debris.

Smear layer removal with passive ultrasonic irrigation and the NaviTip FX: a scanning electron microscopic study

OBJECTIVE

The aim of this study was to compare the effect of continuous, intermittent passive ultrasonic irrigation (PUI) and active scrubbing of irrigants with NaviTip FX (Ultradent, South Jordan, UT) in removing smear layer.

STUDY DESIGN

Forty single-rooted teeth were randomly divided into 5 test groups and subjected to final irrigation with 17% EDTA followed by 2.5% NaOCl for 1 minute each using different activation methods: no activation (control), brushing with NaviTip FX, continuous PUI with irrigant delivered at pulp chamber, continuous PUI with irrigant delivered through the ultrasonic unit, and intermittent PUI. Specimens were examined under scanning electron microscope, and the data were analyzed using Friedman 2-way analysis of variance, Kruskal-Wallis, and Mann-Whitney U tests.

RESULTS

NaviTip FX and intermittent PUI showed significantly lower smear score than other groups at the 3 mm level (P < .05).

CONCLUSIONS

Both brush and intermittent ultrasonic activation were effective in the removal of smear layer from the apical third.

Effectiveness of different final irrigation protocols in removing debris in flattened root canals

This study evaluated in vitro the capacity of debris removal from the apical third of flattened root canals, using different final irrigation protocols. Thirty human mandibular central incisors with a mesiodistal flattened root were prepared using rotary instrumentation by Endo-Flare 25.12 and Hero 642 30.06, 35.02, 40.02 files, irrigated with 2 mL of 1% NaOCl after each file. The specimens were randomly distributed into 5 groups according to the final irrigation of root canals: Group I: 10 mL of distilled water (control), Group II: 10 mL of 1% NaOCl for 8 min, Group III: 2 mL of 1% NaOCl for 2 min (repeated 4 times), Group IV: 10 mL of 2.5% NaOCl for 8 min, and Group V: 10 mL of 2.5% NaOCl for 2 min (repeated 4 times). The apical thirds of the specimens were subjected to histological processing and 6-μm cross-sections were obtained and stained with hematoxylin-eosin. The specimens were examined under optical microscopy at ×40 magnification and the images were subjected to morphometric analysis using the Scion image-analysis software. The total area of root canal and the area with debris were measured in square millimeters. Analysis of variance showed no statistically significant difference (p>0.05) among the groups GI (2.39 ± 3.59), GII (2.91 ± 2.21), GIII (0.73 ± 1.36), GIV (0.95 ± 0.84) and GV (0.51 ± 0.22). In conclusion, the final irrigation protocols evaluated in this study using the Luer syringe presented similar performance in the removal of debris from the apical third of flattened root canals.

Passive ultrasonic irrigation of the root canal: a review of the literature

Ultrasonic irrigation of the root canal can be performed with or without simultaneous ultrasonic instrumentation. When canal shaping is not undertaken the term passive ultrasonic irrigation (PUI) can be used to describe the technique. In this paper the relevant literature on PUI is reviewed from a MEDLINE database search. Passive ultrasonic irrigation can be performed with a small file or smooth wire (size 10-20) oscillating freely in the root canal to induce powerful acoustic microstreaming. PUI can be an important supplement for cleaning the root canal system and, compared with traditional syringe irrigation, it removes more organic tissue, planktonic bacteria and dentine debris from the root canal. PUI is more efficient in cleaning canals than ultrasonic irrigation with simultaneous ultrasonic instrumentation. PUI can be effective in curved canals and a smooth wire can be as effective as a cutting K-file. The taper and the diameter of the root canal were found to be important parameters in determining the efficacies of dentine debris removal. Irrigation with sodium hypochlorite is more effective than with water and ultrasonic irrigation is more effective than sonic irrigation in the removal of dentine debris from the root canal. The role of cavitation during PUI remains inconclusive. No detailed information is available on the influence of the irrigation time, the volume of the irrigant, the penetration depth of the instrument and the shape and material properties of the instrument. The influence of irrigation frequency and intensity on the streaming pattern as well as the complicated interaction of acoustic streaming with the adherent biofilm needs to be clarified to reveal the underlying physical mechanisms of PUI.