Root canals shaped by nickel-titanium instrumentation with automated computerized numerical control systems

Abstract Background To investigate the efficacy of a nickel-titanium (NiTi) file with an automated computerized numerical control (CNC) system for root canal shaping. Methods The movement of the automated device and the insertion angle were investigated. In Experiment 1, simulated resin root canals were randomly divided into four groups (n = 20): manual downward movement using a handpiece (Group 1), vertical downward movement by CNC (Group 2), reciprocating up and down movement by CNC (Group 3), and spiral up and down movement by CNC (Group 4). In Experiment 2, five different insertion angles of the NiTi file were evaluated (n = 20). Four parameters were used to evaluate the shaping ability: change in the working length, central axis offset, curvature variation, and preparation time. Groups were compared using one-way analysis of variance (ANOVA) with significance was set at P < 0.05. Results The change in central axis position in the curved part of the root canal was found to be smaller in Group 4 than in other groups (P < 0.05). The curvature changes and preparation time of Groups 1 and 4 were significantly reduced compared with Groups 2 and 3 (P < 0.05). The variation in working length and curvature in the 5° insertion angle group was significantly smaller than in the other groups (P < 0.05). Conclusions A spiral up and down movement, controlled by the CNC machine, and 5° insertion angle, maintained original root canal shape more precisely than other methods.

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Shaping Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Hybrid and Reciprocating Nickel Titanium Endodontic Instruments

Metals ◽

10.3390/met10020172 ◽

2020 ◽

Vol 10 (2) ◽

pp. 172 ◽

Cited By ~ 1

Author(s):

Saulius Drukteinis ◽

Vytaute Peciuliene ◽

Ruta Bendinskaite ◽

Vilma Brukiene ◽

Rasmute Maneliene ◽

...

Keyword(s):

Fatigue Resistance ◽

Root Canal ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Significance Level ◽

Root Canals ◽

Working Length ◽

Before And After ◽

Canal Transportation ◽

Shaping Ability

The aim of this study was to investigate the shaping ability and cyclic fatigue resistance of Genius (GN) and WaveOne (WO) nickel-titanium (NiTi) instruments. Forty mesial root canals of mandibular molars were randomly divided into two groups, according to the instrument system used for root canal preparation (n = 20): GN and WO. Root canals were prepared to the full working length using the crown-down technique, with up to 40.04 instruments for GN group and 40.08 instruments for WO group. Specimens were scanned with a µCT before and after instrumentation. The changes in 3D parameters and degree of canal transportation were evaluated in the apical, middle and coronal thirds of root canals. Size 25, taper 0.04 (GN) and 0.08 (WO) instruments (n = 20) were used in simulated root canals until fracturing, and the number of cycles to failure (NCF) was recorded. The fractured files were investigated under a scanning electron microscope to characterize fractured surfaces. Data were analyzed using ANOVA post hoc Tuckey’s tests with the significance level set at 5%. The GN system was able to prepare the higher percentage of the canal surface with less canal transportation in all root canal thirds and displayed the higher resistance to cyclic fatigue in comparison to WO instruments (p < 0.05). However, the length of the fractured segments was not significantly different among the groups; meanwhile, SEM investigations revealed the typical topographic characteristics of fractured surfaces. Hybrid GN instruments demonstrated superior shaping ability and resistance to cyclic fatigue. However, both NiTi instrument systems prepared the root canals with no significant shaping errors, considerable changes in 3D parameters and no significant differences in the topographic appearances of the instrument surfaces after fractures.

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Apical extrusion of debris by manual and mechanical instrumentation

Brazilian Dental Journal ◽

10.1590/s0103-64402007000100004 ◽

2007 ◽

Vol 18 (1) ◽

pp. 16-19 ◽

Cited By ~ 10

Author(s):

Lilia E. Leonardi ◽

Diana M. Atlas ◽

Guillermo Raiden

Keyword(s):

Root Canal ◽

Significance Level ◽

Root Canals ◽

Group 4 ◽

Apical Extrusion ◽

Working Length ◽

Significant Difference ◽

Group 3 ◽

Group 2 ◽

Group 1

The aim of the present study was to assess the presence of apically extruded debris and evaluate the influence of canal curvature on the amount of debris produced by manual and mechanical techniques. Forty single-rooted mature teeth with 15 to 30 degree of root canal curvature were selected. The presence of only one foramen was confirmed using a magnifying lens. A size 15 K-file was placed up to the apical foramen to determine the patency. Working length was determined with the same instrument, 1 mm short of the foramen. According to the employed technique, the groups were labeled as follows: Group 1 - Manual instrumentation with Mor-flex files; Group 2 - Mechanical instrumentation with Cursor and Mor-flex files; Group 3 - Manual instrumentation with Flexi-cut files; Group 4 - Mechanical instrumentation with Cursor and Flexi-cut files. During instrumentation, the root canals were irrigated with 20 mL. Debris extruded through the apical foramen was collected using the Myers and Montgomery technique. The values (in mg) were: Group 1: 0.422 ± 0.683; Group 2: 0.688 ± 0.795; Group 3: 0.409 ± 0.323; Group 4: 0.810 ± 0.708. Data were analyzed statistically by ANOVA at 5% significance level. There was no statistically significant difference among the groups (p<0.05). No statistically significant differences were found between slight and moderate curvatures in terms of the amount of extruded debris (p>0.05).

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Assessment of Different Root Canal Preparation Techniques with Rotary Nickel-Titanium Instruments by Novice Students

Dentistry Journal ◽

10.3390/dj6030046 ◽

2018 ◽

Vol 6 (3) ◽

pp. 46 ◽

Cited By ~ 1

Author(s):

Andreas Bartols ◽

David Christofzik ◽

Matthias Krummel ◽

Christian Friedrichs ◽

Tim Pousset ◽

...

Keyword(s):

Root Canal ◽

Nickel Titanium ◽

Technical Quality ◽

Root Canals ◽

Technical Preparation ◽

Working Length ◽

Novice Students ◽

Preparation Strategy ◽

Preparation Techniques

This study investigated which preparation strategy for root canals leads to the best technical preparation quality, and moreover, which is perceived to be performed best by novice students. Sixty-four students were recruited to prepare one simulated root canal with each of the following: FlexMaster files (F), Mtwo files (M), and Reciproc files (R). After preparation, the students assessed the different instrument systems through a questionnaire. The technical quality of the root canal preparations was evaluated by the centering ratio of the preparation. A total of 186 prepared root canals were submitted for evaluation. With R, significantly better centered preparations were achieved when compared to M and F (p < 0.001). The students evaluated R faster than M and F, and evaluated F significantly (p < 0.05) slower than R and M. M was rated as the easiest system to learn and to handle, as well as the best at reaching the working length; therefore, it was evaluated as the overall favorite of the students. A difference was found between the students’ perceptions and their achieved technical quality of root canal preparations.

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Efficacy of a Nickel-Titanium Ultrasonic Instrument for Biofilm Removal in a Simulated Complex Root Canal

Materials ◽

10.3390/ma13214914 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4914

Author(s):

Young-Ryul Oh ◽

Hye-Min Ku ◽

Dohyun Kim ◽

Su-Jung Shin ◽

Il-Young Jung

Keyword(s):

Stainless Steel ◽

Enterococcus Faecalis ◽

Root Canal ◽

Nickel Titanium ◽

Complex Root ◽

Root Canals ◽

Biofilm Removal ◽

Working Length ◽

Before And After ◽

Main Canal

This study evaluated the effectiveness of NiTi ultrasonic tips for Enterococcus faecalis (E. faecalis) biofilm removal in simulated complex root canals. Sixty root canal models consisting of a 30-degree curved main canal and two lateral canals were constructed from polydimethylsiloxane and incubated with E. faecalis. Irrigants in root canals were activated using a manual syringe (SI), a stainless steel (SS) instrument, a nickel-titanium (Ni-Ti) ultrasonic instrument, or a sonic instrument (EA). Instruments of SI, SS, and NiTi-9 groups were placed 9 mm from the apex, whereas those in NiTi-2 and EA groups were placed 2 mm from the apex. The efficacy of each method was determined as the ratio of fluorescence concentration before and after activation. In the apical curved canal, the highest efficacy was found in the NiTi-2 group (99.40%), followed by SI (84.25%), EA (80.38%), SS (76.93%), and NiTi-9 (67.29%) groups. In lateral canals 1 and 2, the efficacy was the highest in the NiTi-2 group and the lowest in the SI group. The NiTi ultrasonic instrument could effectively remove biofilms in the curved canal and lateral canals. This instrument should be introduced close to the working length. An up-and-down motion of the activation instrument is recommended.

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Root canal curvature as a prognostic factor influencing the diagnostic accuracy of radiographic working length determination and postoperative canal axis modification: an in vitro comparative study

BMC Oral Health ◽

10.1186/s12903-021-01446-x ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Bestoon Mohammed Faraj

Keyword(s):

Root Canal ◽

Radiographic Images ◽

The Real ◽

Root Canals ◽

Length Estimation ◽

Working Length ◽

Length Determination ◽

Case Difficulty Assessment ◽

The Impact

Abstract Background Radiographic analysis of tooth morphology is mandatory for accurate calibration of the degree of canal curvature angle and radiographic working length to its real dimensions in case difficulty assessment protocols. This study aimed to determine the impact of the degree of root canal curvature angle on maintaining the real working length and the original canal axis of prepared root canals using a reciprocating rotary instrumentation technique. Methods Radiographic image analysis was performed on 60 extracted single-rooted human premolar teeth with a moderate canal curvature (10°–25°) and severe canal curvature (26°–70°). Working length and longitudinal canal axis were determined using cone-beam computed tomography (CBCT) and digital periapical radiography. The real canal length was determined by subtracting 0.5 mm from the actual canal length. Root canals were prepared using the WaveOne Gold reciprocating file (Dentsply Maillefer, Ballaigues, Switzerland). Results There was no significant relation of the degree of canal curvature angle to the accuracy of radiographic working length estimated on CBCT and digital periapical radiographic techniques (P > 0.05). Postinstrumentation changes in the original canal axis between moderate and severe canal curvature angles, assessed on CBCT and periapical digital radiographic images were statistically non-significant (P > 0.05). Conclusions A standardized digital periapical radiographic method performed similarly to the CBCT technique near to its true working length. No significant interaction exists between the diagnostic working length estimation, postoperative root canal axis modification, and the degree of canal curvature angle, using reciprocating rotary instrumentation technique.

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The ability of Reciproc instruments to reach full working length without glide path preparation: a clinical retrospective study

PeerJ ◽

10.7717/peerj.3583 ◽

2017 ◽

Vol 5 ◽

pp. e3583 ◽

Cited By ~ 9

Author(s):

Andreas Bartols ◽

Bernt-Peter Robra ◽

Winfried Walther

Keyword(s):

Retrospective Study ◽

Root Canal ◽

Primary Root ◽

Primary Treatment ◽

Endodontic Treatment ◽

Binary Logistic Regression Model ◽

Root Canals ◽

Maxillary Molars ◽

Glide Path ◽

Working Length

Background Reciproc instruments are the only contemporary root canal instruments where glide path preparation is no longer strictly demanded by the manufacturer. As the complete preparation of root canals is associated with success in endodontic treatment we wanted to assess the ability and find predictors for Reciproc instruments to reach full working length (RFWL) in root canals of maxillary molars in primary root canal treatment (1°RCTx) and retreatment (2°RCTx) cases. Methods This retrospective study evaluated 255 endodontic treatment cases of maxillary molars. 180 were 1°RCTx and 75 2°RCTx. All root canals were prepared with Reciproc instruments. The groups were compared and in a binary logistic regression model predictors for RFWL were evaluated. Results A total of 926 root canals were treated with Reciproc without glide path preparation. This was possible in 885 canals (95.6%). In 1°RCTx cases 625 of 649 (96.3%) canals were RFWL and in 2°RCTx cases 260 of 277 (93.9%). In second and third mesiobuccal canals (MB2/3) 90 out of 101 (89.1%) were RFWL with Reciproc in 1°RCTx and in the 2°RCTx treatment group 49 out of 51 cases (96.1%). In mesio-buccal (MB1) canals “2°RCTx” was identified as negative predictor for RFWL (OR 0.24 (CI [0.08–0.77])). In MB2/3 canals full working length was reached less often (OR 0.04 (CI [0.01–0.31])) if the tooth was constricted and more often if MB2/3 and MB1 canals were convergent (OR 4.60 (CI [1.07–19.61])). Discussion Using Reciproc instruments, the vast majority of root canals in primary treatment and retreatment cases can be prepared without glide path preparation.

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Root Canal Stripping: Malpractice or Common Procedural Accident—An Ethical Dilemma in Endodontics

Case Reports in Dentistry ◽

10.1155/2016/4841090 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5

Author(s):

Ionela Elisabeta Ciobanu ◽

Darian Rusu ◽

Stefan-Ioan Stratul ◽

Andreea Cristina Didilescu ◽

Corina Marilena Cristache

Keyword(s):

Risk Factors ◽

Ethical Dilemma ◽

Root Canal ◽

Tooth Extraction ◽

Nickel Titanium ◽

Middle Section ◽

Root Canals ◽

Legal Consequences ◽

Curved Root Canals

Root canal stripping is defined as an oblong, vertical perforation that appears especially in the middle section of curved root canals during endodontic treatments with nickel-titanium (Ni-Ti) instruments. Its occurrence may drastically affect the outcome of the treatment, transforming a common otherwise efficient endodontic procedure into a complication such as tooth extraction. In order to discuss the ethical and legal consequences, two cases of dental strip perforations are herewith presented. Due to the existence of risk factors for dental strip perforation, experience of the clinician and the use of magnification and modern imagistic methods (CBCT) may avoid or reduce the frequency of this type of accidents. Under correct working circumstances, dental stripping should not be regarded as a malpractice but as a procedural accident. However, the patient must always be informed, before and during the endodontic procedure, about the event and the possible complications that may occur.

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The Influence of Cervical Preflaring of Root Canal on Determination of Initial Apical File using Gates Glidden Drills, Protaper, Race and Diamond-Coated Galaxy Files

The Journal of Contemporary Dental Practice ◽

10.5005/jcdp-13-4-554 ◽

2012 ◽

Vol 13 (4) ◽

pp. 554-558 ◽

Cited By ~ 1

Author(s):

TS Ashwini ◽

Sonam Bhandari

Keyword(s):

Root Canal ◽

Accurate Determination ◽

Size Determination ◽

File Size ◽

Root Canals ◽

Multiple Comparison Test ◽

Rotary Instruments ◽

Working Length ◽

Maxillary Premolars

ABSTRACT Aim To investigate the influence of cervical preflaring on apical file size determination using four different rotary instruments. Materials and methods Fifty root canals from extracted human maxillary premolars with complete root formation, straight roots were used for the study. Access opening was done and the working length established with 8 no K-file for each canal. Teeth were randomly divided into five groups of 10 canals. In Group 1- no preflaring was done and acted as control and in Groups 2, 3, 4 and 5 cervical and middle third preflaring of the root canals were done using Gates Glidden drills, Protaper instruments, Race instruments and Galaxy files respectively. After preflaring, the apical file size determination was done and the initial apical file (IAF) was fixed at the working length. Teeth were sectioned transversally 1 mm from the apex, with the binding file in position. The samples were imaged under stereomicroscope with 30× magnification. Root canal and file maximum diameters were recorded for each sample. The readings were subjected to analysis of variance test and Scheffe's multiple comparison test. Results Preflaring with Race instruments lead to most accurate determination of the IAF. It was followed by Protaper, Galaxy files and Gates Glidden drills. Conclusion Traditional method of apical size determination may lead to a substantial underestimation of actual canal size. Cervical preflaring increases the accuracy of apical size determination. Clinical significance Thus, cervical preflaring is recommended before selection of IAF as it increases the accuracy of apical size determination. How to cite this article Ashwini TS, Bhandari S. The Influence of Cervical Preflaring of Root Canal on Determination of Initial Apical File using Gates Glidden Drills, Protaper, Race and Diamond-Coated Galaxy Files. J Contemp Dent Pract 2012; 13(4):554-558.

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Microbial Leakage of Cavit, IRM, and Temp Bond in Post-prepared Root Canals Using Two Methods of Gutta-percha Removal: An In Vitro Study

The Journal of Contemporary Dental Practice ◽

10.5005/jcdp-6-3-53 ◽

2005 ◽

Vol 6 (3) ◽

pp. 53-61 ◽

Cited By ~ 9

Author(s):

Hanan Balto ◽

Saad Al-Nazhan ◽

Khulood Al-Mansour ◽

Moneera Al-Otaibi ◽

Yunus Siddiqu

Keyword(s):

Root Canal ◽

Bacterial Suspension ◽

Control Group ◽

Endodontically Treated Teeth ◽

Root Canals ◽

Gutta Percha ◽

Working Length ◽

Significant Difference ◽

Post Space

Abstract The aim of this study was to evaluate the integrity of the coronal seal of Temp-Bond and compare it to Cavit and IRM after post space preparation using S. faecalis as a microbial tracer. In addition, the affect of two methods of gutta percha removal on the apical seal of root canal fillings was also evaluated. Forty extracted human single rooted teeth were prepared chemomechanically and obturated with gutta percha and AH26 sealer cement using the lateral cold condensation technique to a standardized working length of 15 mm. About 10 mm of the coronal gutta-percha was removed with either Peeso-reamer or a hot plugger. The roots were divided into three experimental groups of 10 roots and a control group. Each experimental group was subdivided equally into two groups of 15 each according to the method of post space preparation. Cavit, IRM, and Temp-Bond were used to seal the access opening. Each root was fixed in a cuvette containing Tryptic Soya Broth which, covered 2 mm of the root apex. Bacterial suspension was introduced through pipette. Fresh bacterial suspension was added every week, and the system was monitored daily for the growth of microorganisms for a period of one month. The results showed there was no significant difference in terms of coronal leakage between the three coronal materials used (P=0.478), but the methods of gutta-percha removal did have an impact on the apical leakage (P=0.047). The mean value showed the Peeso-reamer provided less leakage compared to using a hot plugger during the 30-day experimental time period. It was concluded the temporary type of coronal seal of endodontically treated teeth will not prevent coronal leakage if left for a long period of time. In addition, permanent cementation of the post with the coronal restoration should be carried out as soon as possible to prevent recontamination of the root canal. Citation Balto H, Al-Nazhan S, Al-Mansour K, Al-Otaibi M, Siddiqu Y. Microbial Leakage of Cavit, IRM, and Temp Bond in Post-prepared Root Canals Using Two Methods of Gutta-percha Removal: An In Vitro Study. J Contemp Dent Pract 2005 August;(6)3:053-061.

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Clinical features and endodontic treatment of two-rooted mandibular canines: Report of four cases

Srpski arhiv za celokupno lekarstvo ◽

10.2298/sarh1410592s ◽

2014 ◽

Vol 142 (9-10) ◽

pp. 592-596 ◽

Cited By ~ 2

Author(s):

Igor Stojanac ◽

Milica Premovic ◽

Milan Drobac ◽

Bojana Ramic ◽

Ljubomir Petrovic

Keyword(s):

Root Canal ◽

Case Reports ◽

Anatomical Variation ◽

Anatomical Variations ◽

Endodontic Treatment ◽

Careful Examination ◽

Root Canals ◽

Working Length ◽

Canal Systems ◽

Root Canal Morphology

Introduction. Predictable endodontic treatment depends on the dentist?s knowledge about root canal morphology and its possible anatomic variations. The majority of mandibular canines have one root and root canal, but 15% may have two canals and a smaller number may have two distinct roots. The following clinical reports describe endodontic treatment of mandibular canines with two roots and two root canals. Outline of Cases. Four clinical case reports are presented to exemplify anatomical variation in the human mandibular canine. Detailed analysis of the preoperative radiographs and careful examination of the pulp chamber floor detected the presence of two root canal orifices in all canines. Working length was determined with an electronic apex locator and biomechanical preparation was carried out by using engine driven BioRaCe Ni-Ti rotary instruments in a crown-down manner, followed by copious irrigation with 1% sodium hypochlorite. Definitive obturation was performed using cold lateral condensation with gutta-percha cones and Top Seal paste. The treatment outcome was evaluated using postoperative radiographs. Conclusion. Endodontists should be aware of anatomical variations of the treated teeth, and should never presume that canal systems are simple.

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