Root Canal Shaping Research Articles

ASPECTE ALE TRATAMENTULUI BIOMECANIC DE CANAL – TEHNICA STEP-BACK. STUDIU IN VITRO

Evaluation of post-operative root canal shape have been performed using simulated root canals in resin blocks and magnification analysis (stereomicroscope) have been used for the study. The technique selected was stepback with conventional hand stainless steel instruments. The aim of studies on post-operative root canal shape is to evaluate the conicity, taper and flow and maintenance of original canal shape and to record the degree and frequency of straightening, apical transportation, ledging, zipping, teardrops, elbows. Ideal preparation forms for the root canals can be possible without any preparation errors with circular incorporation of the original canal cross section – if the technique starts with adequately precurved negotiating files. Preparation errors (zips, canal transportation, apical perforations, elbows, teardrops, etc) can occur mostly when stainless steel hand instruments (K-file) are used for moderate to severe curved of root canals, especially K-file with cutting tips and not prebent. Ideal preparation shape without any preparation errors could be a final shape and adequate shape even for conventional hand files and step-back technique. For the first area of step back technique, even for the begining, we can usually use various prebent stainless steel hand instruments for pathfinding. In many cases, conventional hand instruments produces adequate shapes for the root canals. For this final shape, is important to use adequately precurved negotiating files. Conventional stainless stell are rigid enough that thay should be precurved to match the curvature of the canal during instrumentation. Conventional hand instruments has two basic design, Kerr-file and Kerr-reamer. Kerr-file could be used to enlarge the canal with a longitudinal filing action. Kerr-reamer may used in a same fashion, but is much more flexible instrument than K-file. Noncutting tip follow the canal better than instruments with active tips – clinically usefull element.

The Impact of Apical Patency in the Success of Endodontic Treatment of Necrotic Teeth with Apical Periodontitis: A Brief Review.

Accumulation of soft tissue or dentinal remnants in the apical region is a common event that can cause blockage of root canals. This event can be avoided if apical patency is performed during the root canal shaping procedures. However, there is no consensus on the role of apical patency in relation to the success of endodontic treatment of necrotic teeth with apical periodontitis. Therefore, the purpose of this paper was to conduct a brief review on the role of apical patency in guaranteeing the success of endodontic treatments of necrotic teeth with apical periodontitis considering two other key points; the root canal anatomy and microbiology.

A Micro Computed Tomography Assessment of New Carrier-Based Root Canal Fillings

Background: The main aim of the present study is to qualify and quantify voids formation of root canals obturated with GuttaCore (GC) and experimental Hydroxyapatite polyethylene (HA/PE) as new carrier-based root canal fillings by using micro computed tomography scan. Materials and methods: In the present study, eight straight single-rooted human permanent premolar teeth are selected and disinfected, then stored in distilled water. The teeth decoronated leaving a root length of 12mm each. The root canals instrumented by using crown down technique and the apical diameter of the root canal prepared to a size # 30/0.04 for achieving standardized measurements. A 5mL of 17% EDTA used to remove the smear layer followed by 5mL of 2.5% NaOCl and rinsing with normal saline. Then the shaped root canals were randomly subdivided into two groups of 4 teeth each according to the carrier-based obturation system use, GuttaCore or experimental HA/PE. Afterwards, the obturated roots stored at 37°C with 100% humidity for 72 hours to allow for complete setting of the sealer. Micro-CT was then scanned to quantify the voids within the root canal space. The data were statistically analyzed by one-way ANOVA and post hoc comparison tests (α=0.05). Results: The root canals obturated with both obturation systems, GuttaCore andexperimental HA/PE showed voids formation, particularly at the apical third of the root canal. GC obturation showed a lower percentage of voids volume (1.54%) than the experimental HA/PE obturation (2.3%). The void volume percentage in the GuttaCore system, however, was non-significantly different (P> 0.05) in comparison with the experimental PE/HA system. Conclusions: GuttaCore and experimental HA/PE obturators exhibited voids formation within the entire root canal space. The experimental HA/PE obturator is comparable to the GuttaCore obturator in terms of voids qualification

Mechanical Behavior of a NiTi Endodontic File During Insertion in an Anatomic Root Canal Using Numerical Simulations

Superelastic NiTi shape memory alloys (SMA) have biomedical applications including rotary endodontic files. These alloys are used thanks to their flexibility, which is due to solid-solid martensitic transformation. Unfortunately, the intracanal file separation can occur during canal preparation. To avoid this problem and to have a good idea of the mechanical behavior of these instruments, finite elements simulations taking into account the real shape of root canals are proposed in this study. This is possible by using a well-adapted model describing all the particularities of SMA and representative limit conditions. The behavior model has been validated in previous studies under complex loadings. It is implemented in ABAQUS® finite elements software. The anatomic shapes of root canals are extracted by microtomography using a real tooth. They are applied as limit conditions in realized simulations to be as near as possible to clinical conditions. The mechanical behavior of an endodontic file is then simulated during insertion in a root canal without and with rotation. This permits to obtain different information like the loading applied to the instrument during its use, the stress, and the phase transformation fields through the file. This is useful not only for clinical use but also for new NiTi endodontic instruments design.

A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques

IntroductionApical extrusion of irrigants and debris is an inherent limitation associated with cleaning and shaping of root canals and has been studied extensively because of its clinical relevance as a cause of flare-ups. Many factors affect the amount of extruded intracanal materials. The purpose of this study was to assess the bacterial extrusion by using manual, multiple-file continuous rotary system (ProTaper) and single-file continuous rotary system (One Shape). MethodsForty-two human mandibular premolars were inoculated with Enterococcus faecalis by using a bacterial extrusion model. The teeth were divided into 3 experimental groups (n = 12) and 1 control group (n = 6). The root canals of experimental groups were instrumented according to the manufacturers' instructions by using manual technique, ProTaper rotary system, or One Shape rotary system. Sterilized saline was used as an irrigant, and bacterial extrusion was quantified as colony-forming units/milliliter. The results obtained were statistically analyzed by using one-way analysis of variance for intergroup comparison and post hoc Tukey test for pair-wise comparison. The level for accepting statistical significance was set at P < .05. ResultsAll the instrumentation techniques resulted in bacterial extrusion, with manual step-back technique exhibiting significantly more bacterial extrusion than the engine-driven systems. Of the 2 engine-driven systems, ProTaper rotary extruded significantly more bacteria than One Shape rotary system (P < .05). ConclusionsThe engine-driven nickel-titanium systems were associated with less apical extrusion. The instrument design may play a role in amount of extrusion.

Dentinal crack formation during root canal preparations by the twisted file adaptive, Reciproc and WaveOne instruments

Objective:This study aimed to compare the frequency of dentinal microcracks after root canal shaping with 2 reciprocating (Reciproc and WaveOne) and 1 combined continuous reciprocating motion twisted files adaptive (TFA) rotary system.Materials and Methods:Ninety molars were chosen and divided into three groups of 30 each. Root canal preparation was achieved by using Reciproc R25, Primary WaveOne and TFA systems. All the roots were horizontally sectioned at 15, 9, and 3 mm from the apex. The slices were then viewed each under a microscope at × 25 magnification to determine the presence of cracks. The absence/presence of cracks was recorded, and the data were analyzed with a Chi-square test. The significance level was set at P < 0.05.Results:Instrumentation with Reciproc produced significantly more complete cracks than WaveOne and TFA (P = 0.032). The TFA system produced significantly less cracks then the Reciproc and WaveOne systems apically (P = 0.004).Conclusions:Within the limits of this study, the TFA system caused less cracks then the full reciprocating system (Reciproc and WaveOne). Single-file reciprocating files produced significantly more incomplete dentinal cracks than full-sequence adaptive rotary motion.

Incidence of dentinal cracks after root canal preparation with ProTaper Gold, Profile Vortex, F360, Reciproc and ProTaper Universal instruments.

To assess the effect of root canal preparation using ProTaper Gold, Profile Vortex, F360, Reciproc and ProTaper Universal instruments on dentinal crack formation. Ninety mandibular central incisor teeth with mature apices and straight canals (<5° ) were selected and stored in distilled water. Fifteen teeth were left unprepared (control group) and the remaining 75 teeth were assigned to the five root canal shaping groups (n=15): ProTaper Gold, ProFile Vortex, F360, Reciproc and ProTaper Universal. All the roots were sectioned perpendicular to the long axis at 3, 6 and 9mm from the apex with a low-speed saw under water cooling. The slices were then viewed through a stereomicroscope at 25× magnification. The presence of dentinal cracks was determined by photographing all samples using a digital camera. All the experimental groups, except F360, produced significantly more cracks than the control group (P<0.05). No significant difference was observed amongst the groups at the 6 and 9mm levels (P>0.05). The ProTaper Universal group produced significantly more cracks than the control, ProTaper Gold, ProFile Vortex, F360 and Reciproc groups at the apical section (3mm) (P<0.05). All the systems that were tested produced dentinal cracks. There was no significant difference between the control and F360 groups in terms of dentinal crack formation.

Incidence of Dentinal Cracks after Root Canal Preparation with Twisted File Adaptive Instruments Using Different Kinematics

IntroductionThe purpose of the present study was to assess the effect of root canal instrumentation using Twisted File Adaptive instruments (Axis/SybronEndo, Orange, CA) with different kinematics (adaptive motion, 90° clockwise [CW]–30° counterclockwise [CCW], 150° CW–30° CCW, 210° CW–30° CCW, and continuous rotation) on crack formation. MethodsOne hundred five mandibular central incisor teeth were selected. Fifteen teeth were left unprepared (control group), and the remaining 90 teeth were assigned to the 5 root canal shaping groups as follows (n = 15): adaptive motion, 90° CW–30° CCW, 150° CW–30° CCW, 210° CW–30° CCW, continuous rotation, and hand file. All the roots were sectioned horizontally at 3, 6, and 9 mm from the apex with a low-speed saw under water cooling, and the slices were then viewed through a stereomicroscope at 25× magnification. Digital images of each slice were captured using a camera to determine the presence of dentinal cracks. ResultsNo cracks were observed in the control group, and the continuous rotation group had more cracks than the reciprocation groups (90° CW–30° CCW, 150° CW–30° CCW, and 210° CW–30° CCW) (P < .05). Both the continuous rotation and adaptive motion groups had significantly more dentinal cracks than the hand file group (P < .05). Regarding the different sections (3, 6, and 9 mm), there was a significant difference between the experimental groups at the 9-mm level (P < .05). ConclusionsThe incidence of dentinal cracks is less with TF Adaptive instruments working in 210° CW–30° CCW reciprocating motion compared with working in continuous rotation and adaptive motion.

Root canal shaping by single-file systems and rotary instruments: a laboratory study.

The aim of this study was to compare the shaping ability of two single-file systems and conventional rotary instruments in severely curved root canals of extracted human molars. Mesiobuccal canals of 120 mandibular molars with angles of curvature ranging between 25(°) and 35(°) and radii of curvature from 5 to 9 mm, were divided into three groups (n=40). In each group the canals were instrumented with either WaveOne (W), Reciproc (R) or ProTaper (P). The time required for canal shaping and the frequency of broken instruments were recorded. The standardized pre and post-instrumentation radiographs were taken to determine changes in working length (WL) and straightening of canal curvature. The presence of blockage or perforation was also evaluated. Data were analyzed using the one-way analysis of variance (ANOVA) and post-hoc Tukey's test. The level of significance was set at 0.05. Both single-instrument systems reduced the canal preparation time by approximately 50% (P<0.05). No incidence of broken instruments from single-file systems was reported; however, two F2 instruments in the P group were broken (P<0.05). Reduction in WL and straightening of canal curvature was observed in all three systems with the highest scores belonging to P system (P<0.05). No case of blockage or perforation was found during shaping in any group. Single-file systems shaped curved canals with substantial saving in time and a significant decrease in incidence of instrument separation, change in WL, and straightening of canal curvature.

A review of instrumentation kinematics of engine‐driven nickel–titanium instruments

Over the years, NiTi alloys have become indispensable materials in endodontic treatment. With technological advancements in metallurgy, manufacturers have attempted to produce instruments with enhanced features. In parallel with these developments, endodontic motors have undergone improvements in terms of torque control and kinematics that are adjustable in different directions. This review presents an overview of the advancements in instrumentation kinematics and the effect of instrumentation kinematics on root canal shaping procedures and instrument performance. The literature search for this narrative review was conducted in Google Scholar, Scopus, PubMed and Web of Science using the keywords 'kinematics and endodontics' and 'reciprocation and endodontics'. In addition, historical literature was searched using the keyword 'nickel-titanium and endodontics'. Overall, 143 articles were included up to 2015.

Minimally Invasive Endodontic Management of a Maxillary Second Premolar with an S-shaped Root Canal using the Self-adjusting File

ABSTRACTThe main objective of an endodontic treatment is thorough shaping and cleaning of the root canal system, with the aim to obtain a fluid tight seal by a biocompatible obturating material. Complex unusual root canal morphology is an often-occurring phenomenon. Knowledge and understanding the unusual root canal morphology predicts the successful outcome in endodontic treatment. One such variant root canal morphology is the ‘S’ shaped root canal.The self-adjusting file (SAF) is a hollow compressible file made up of nickel-titanium lattice. The new concept associated with the SAF is that it adapts itself to the anatomical shape of the root canal and performs mechanical shaping and chemical cleaning with continuous irrigation simultaneously.This case report discusses endodontic treatment of a maxillary second premolar with a ‘S’ shaped root canal and its successful management with the SAF.How to cite this articlePawar AM, Pawar MG, Kokate SR. Minimally Invasive Endodontic Management of a Maxillary Second Premolar with an S-shaped Root Canal using the Self-adjusting File. J Contemp Dent 2015;5(1):35-37.

Single File Niti-Rotary Systems

The cleaning and shaping of root canals is a major step in root canal treatment procedure, which aims at removal of all the tissue debris from the root canal space while removing the inner layers of root canal dentin. With Nickel titanium (NiTi) rotary instruments this goal is easier to achieve, even in curved root canals. The recently introduced Single file NiTi-rotary systems such as WaveOne, Reciproc, OneShape&F360 claim to be able to completely prepare and clean root canals with only one instrument. Use of single file rotary systems, are cost effective, time saving, reduce instrument fatigue and possible crosscontamination. The purpose of this article is to review single file Niti-Rotary systems for canal preparation.

Evaluation of Root Canal Cleaning and Shaping Efficacy of Three Engine-driven Instruments: SafeSider, ProTaper Universal and Lightspeed LSX.

To compare the cleaning effectiveness and shaping ability of SafeSider, ProTaper Universal and Lightspeed rotary instruments during the preparation of curved root canals in extracted human teeth. A total of 63 roots with curved root canals were divided into three groups. Canals were prepared using SafeSider, ProTaper Universal or Lightspeed LSX. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures and loss of working length were determined with a computer image analysis program. The amounts of debris at the apical 5 mm were quantified on the basis of a numerical evaluation scale. The data were analyzed statistically using the two-way analysis of variance (ANOVA). There was significantly more transportation among the Lightspeed LSX group compared to the SafeSider and ProTaper Universal groups only at the 4 mm level (p < 0.05). The ProTaper Universal instruments performed significantly faster than other groups. No significant differences were observed between the three engine-driven instruments with regards to debris removal. SafeSider, ProTaper Universal and Lightspeed LSX rotary instruments maintained the original canal curvature well at the apical 3 mm and were safe to use. No difference was found in cleaning efficacy and none rendered the apical part of the canal free of debris. SafeSider, ProTaper Universal and Lightspeed LSX rotary instruments are safe to use in curved root canals.

Root Canal Shaping by Continuous or Reciprocating Rotation : The Protaper System versus the Endo-Eze Tilos System

Root Canal Shaping by Continuous or Reciprocating Rotation : The Protaper System versus the Endo-Eze Tilos System

Evolution of the role of phototherapy during endodontic decontamination.

A microbe free root canal space before obturation leads to higher success rate and conventional chemo-mechanical debridement might not achieve this goal completely. First trials of laser in dentistry started from surgical intervention on caries and bones of oral cavity and extended to prepare cavities and even shaping root canals. Afterward lasers were implicated soon into direct debridement of root canal space. Anyhow failure of laser to remove debris totally from root canal space is demonstrated recently, additionally it might lead to damages to surrounding tissues or inorganic material of root canal if be used without precaution. Nowadays the theory of light assisted protocols became another start point for laser in endodontics. Laser has been introduced as an adjuvant to conventional debridement of root canals. We used Medline search engine to collect scientific publications to edit this review article in purpose of revealing the evolution of laser position from an ultimate cleaning methodology to an adjuvant to conventional root canal disinfection protocols.

F360 and F6 Skytaper: SEM evaluation of cleaning efficiency.

Root canal preparation may produce a large quantity of smear layer that covers canal walls. Single-file systems have recently appeared, with the aim of reducing the number of steps and files to reach a correct endodontic treatment. The purpose of this study was to evaluate by SEM the root canal walls after instrumentation with F360 (Komet, Brasseler GmbH & Co., Lemgo, Germany) and F6 Skytaper (Komet, Brasseler GmbH & Co., Lemgo, Germany), in order to evaluate the presence/absence of smear layer and the presence/absence of open tubules on the root canal walls at coronal, middle, and apical third of each sample. Twenty single-rooted freshly extracted teeth were selected and divided into 2 groups. For each group root canals were shaped with F360 (Komet, Brasseler GmbH & Co., Lemgo, Germany) and F6 Skytaper (Komet, Brasseler GmbH & Co., Lemgo, Germany) instruments under irrigation with 5,25% NaOCl and 17% EDTA. Specimens were fractured longitudinally and analyzed by SEM at standard magnification of 5000x. The presence/absence of smear layer and the presence/absence of open tubules at the coronal, middle, and apical third of each canal were evaluated using a 5-step scale for scores. Numeric data were analyzed using Kruskall-Wallis and Mann-Whitney U statistical tests and significance was predetermined at P <0.05. This study did not reveal differences among two groups at the coronal and apical third. The apical third showed the highest values of scores for all Ni-Ti systems used. Significant differences in smear layer scores were recorded among the Ni-Ti systems at middle canal level (P < 0.05), where F6 Skytaper showed significantly lower scores than F360. Within the limitation of this study, F360 and F6 Skytaper rotary instruments seem to be effective in shaping root canals with good debridement from canal walls, without significant differences between the two systems as it regards the coronal third and the apical third, the area where more debris is still visible. Instead, in the middle third F6 Skytaper seems to be more effective than F360, with statistically significative differences between the two systems.

Nickel-Titanium Single-file System in Endodontics

This work describes clinical cases treated with a innovative single-use and single-file nickel-titanium (NiTi) system used in continuous rotation. Nickel-titanium files are commonly used for root canal treatment but they tend to break because of bending stresses and torsional stresses. Today new instruments used only for one treatment have been introduced. They help the clinician to make the root canal shaping easier and safer because they do not require sterilization and after use have to be discarded. A new sterile instrument is used for each treatment in order to reduce the possibility of fracture inside the canal. The new One Shape NiTi single-file instrument belongs to this group. One Shape is used for complete shaping of root canal after an adequate preflaring. Its protocol is simple and some clinical cases are presented. It is helpful for easy cases and reliable for difficult canals. After 2 years of clinical practice, One Shape seems to be helpful for the treatment of most of the root canals, with low risk of separation. After each treatment, the instrument is discarded and not sterilized in autoclave or re-used. This single-use file simplifies the endodontic therapy, because only one instrument is required for canal shaping of many cases. The respect of clinical protocol guarantees predictable good results.

Evaluation of Root Canal Shaping Associated with Nickel-titanium File System by Glide Path of ProGlider

Evaluation of Root Canal Shaping Associated with Nickel-titanium File System by Glide Path of ProGlider

A comparative evaluation of two root canal instrumentation techniques for preparation of oval shaped root canals using cone beam computed tomography-an in vitro study

A comparative evaluation of two root canal instrumentation techniques for preparation of oval shaped root canals using cone beam computed tomography-an in vitro study

Clinical Update on Nickel-Titanium Rotary Instruments

ABSTRACT In the last decade, nickel-titanium (NiTi) rotary canal instruments have proved to be valuable for root canal therapy because of their exceptional ability to shape root canals with potentially fewer procedural complications. The purpose of this clinical update article is to bring clinicians up to date with the current and popular endodontic rotary NiTi instrument systems. How to cite this article Jain P, Nayan S, Keswani E, Pawar S. Clinical Update on Nickel-Titanium Rotary Instruments. World J Dent 2015;6(2):97-103.