NiTi Rotary Systems Research Articles

Radix Entomolaris in Mandibular First Molars: Report of 3 Cases

The radix entomolaris is an anatomical variation characterized by the presence of an additional root located in the distal-lingual region of mandibular molars. An accurate diagnosis is necessary to plan and institute effective endodontic therapy for teeth with this condition. The aim of this report was to present three cases of endodontic management in permanent mandibular first molars with radix entomolaris using contemporary technical resources. For diagnosis, periapical radiographs indicated the possibility of morphological alterations, which were confirmed in two cases by cone beam computed tomography (CBCT). Ultrasonic tips and magnification with operative microscopy were the auxiliary resources used for locating the root canals, which were prepared with NiTi rotary instrument systems and filled with gutta-percha by using the lateral condensation technique and AH Plus sealer. Resources such as periapical radiography, CBCT, magnification with operative microscopy, ultrasonic devices and NiTi instruments can be extremely valuable for use in the diagnosis and clinical approach to endodontic treatment of mandibular first molars with radix entomolaris.

Evaluation of apical root defects during canal instrumentation with two different nickel-titanium (NiTi) systems by optical coherence tomography (OCT) scan

Background/purposeCanal instrumentation with rotary nickel-titanium (NiTi) instruments might weaken the dentinal wall. This study aims to investigate the apical root defects during canal instrumentation with two NiTi rotary systems by using optical coherence tomography (OCT) scans. Materials and methodsTwenty mandibular incisors were selected and divided into two groups instrumented using HyFlex CM (HCM) and ProTaper Universal (PTU) systems. OCT scans were taken immediately after canal instrumentation with file #25, #30 and #40. Each cross-sectional reconstructed image of 1, 2 and 3 mm from the apex was examined, root cracks were scored, and dentin thickness was measured at 12 sites. The risk sites with dentin thickness less than 0.30 mm were recorded. ResultsIn HCM group, no cracks were observed after instrumentation with file #30/.06, while in PTU group, root cracks were found in 6 teeth with a total score of 9 after using F3 (#30/.09) (P < 0.05). After file #40, 8 teeth with cracks had a score of 14 in PTU group, while one tooth was observed crack with a score of 1 in HCM group (P < 0.05). The number of risk sites in PTU group was 49 (13.16%), which was significantly more than the 28 (7.78%) in HCM group (P < 0.05) when canals were instrumented with file #30. ConclusionWithin the limitations of this study, when the canals of mandibular incisors were instrumented with size #30 and #40 files, OCT scans showed less root defects in HCM group.

Comparative assessment of apically extruded debris using Protaper Next, Hyflex CM and EdgeFile X7 nickel titanium instruments (An in vitro Study)

Aim: To compare the amount of extruded debris with three endodontic NiTi engine driven systems, Protaper Next, Hyflex CM and EdgeFile X7. Material and Methods: A total number of 42 freshly extracted human premolars were selected. Teeth were divided randomly into three equal groups (14 teeth each group) according to type of Ni-Ti rotary file system; (A) Protaper Next, (B) Hyflex CM and (C) EdgeFile X7. Standard Access cavity prepared and checked for patency using K file #10 and #15. Root canal instrumentation on the single canal lower premolars was done. Debris was collected after root canal instrumentation in pre-weighed Eppendorf tubes. The Eppendorf tubes were weighed 2 times on the analytical balance. First weight: Before instrumentation. Second weight: After evaporation of moisture and irrigant and incubation. Welch test was used for comparison between the three groups. Results: There was no statistically significant difference between the amounts of debris extrusion of the three groups Conclusion: All endodontic rotary instruments tested produced apical extrusion of debris.

The comparison of cyclic fatigue resistance of two different reciprocal files according to different access angles into the root canal

Aim: Root canal preparation is one of the most important steps of root canal treatment. Preparation procedure includes disinfection and shaping protocols. Ni-Ti rotary file systems are usually used for shaping. The biggest disadvantage of the usage of Ni-Ti rotary file systems is that the file gets broken during the treatment. There are many reasons for the breakage of files. One of the reasons may be the increase in the access angle. The purpose of this study is to compare the cyclic fatigue of reciprocating Reciproc and WaveOne Gold rotary systems according to different angles of accessing the root canal of Ni-Ti files.&#x0D; Methodology: In our study, 90 root canal files were used, 45 of which is Reciproc R25 (VDW GmbH, Munich, Germany) and the other 45 of which is WaveOne Gold Primary 25/07 (Dentsply, Maillefer, Ballaigues, Switzerland). Specially designed and manufactured stainless steel artificial roots whose curvature angle is 60° and curvature radius is 5 mm, which replicates the clinical conditions, were arranged. By enabling the files access the roots at 0°- 15°- 30° degrees, the lap numbers that they do till they break due to cyclic fatigue were examined.&#x0D; Results: When looking at the lap numbers that the Reciproc and WaveOne Gold root canal files do till they break, at accessing the roots at the same angles WaveOne Gold root canal file makes more lap numbers at all angles when compared with the Reciproc root canal file. Significant results were found when the groups were compared within one another and between groups and among all numeric data in the statistical analysis performed. It was also found that WaveOne Gold root canal file had more cyclic fatigue resistance. When the groups were compared within one another, it was found that the increase in the root access angle decreases the cyclic fatigue resistance of the files (p&lt;0.05). No significant difference was found in the statistical analysis for comparison of the length of the broken file pieces (p=0.01). It was analyzed that when the broken files were examined via scanning electron microscope, file breakages occurred due to cyclic fatigue.&#x0D; Conclusion: Not only do the design features and production technology affect the breakage resistance due to cyclic fatigue of the root canal, the access angle to the roots affects the cyclic fatigue of the root canal files, as well.&#x0D; &#x0D; How to cite this article: Adıgüzel Ö, Dundar M, Kaya S. The comparison of cyclic fatigue resistance of two different reciprocal files according to different entry angles into the root canal. Int Dent Res 2021;11(Suppl.1):114-21. https://doi.org/10.5577/intdentres.2021.vol11.suppl1.18&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Canal Transportation and Volumetric Dentin Removal Abilities of Ni-Ti Rotary File Systems in Curved Primary Root Canals: CBCT Study

Current improvements in nickel-titanium (Ni-Ti) rotary file systems have created a paradigm shift in the root canal therapy of primary teeth. Therefore, it is necessary to perform a comprehensive evaluation regarding the efficiencies of newly manufactured instruments for different parameters. The current study was conducted to evaluate the abilities of RaceEvo, R-Motion, ProTaper Gold (PTG) systems in curved primary root canals with regard to the patterns of canal transportation and volumetric dentin removal by using cone-beam computed tomography (CBCT). Two experimental sets were designed following the determination of experimental groups by using pre- and post-operative CBCT data: canal transportation and volumetric dentin removal. The highest amount of canal transportation was significantly detected in the PTG group in comparison to RaceEvo and R-Motion groups. When the mean values of volumetric dentin removal data were analyzed across all groups, the PTG group again exhibited the significantly highest value of dentin removal volumetrically, compared to RaceEvo, R-Motion and manual instrumentation groups. It is possible to state that R-Motion and RaceEvo rotary systems could be used as reliable alternatives without causing adverse mechanical effects and maintaining the original root canal anatomy of curved primary root canal systems compared with PTG rotary systems and manual instrumentation, with a high diagnostic sensitivity of CBCT in pediatric endodontics when the alternative methods are not adequate.

Principles of techniques for cleaning root canals

Chemomechanical root canal preparation involves both mechanical instrumentation and antibacterial irrigation, and is aimed primarily at removing microorganisms from the root canal system. For this essential step of root canal therapy, a number of devices and procedures have been developed and described. Nickel-titanium (NiTi) rotary devices have been a standard in clinical endodontics since their debut in 1988 because of their excellent ability to form root canals with possibly fewer procedural problems. Basic metallurgy of the alloy, including fracture processes and their relevance to canal anatomy, is required for safe clinical use of NiTi devices. This study examines the biological principles of root canal preparation, with a focus on the proper use of contemporary rotary NiTi instrumentation techniques and systems. The role and properties of contemporary root canal irrigants is also discussed.

Evaluation of postoperative pain and periapical healing after single visit endodontic treatment using Rotary Ni-Ti system

Purpose: This study was designed to evaluate the postoperative pain and periapical healing after single and two visits endodontic treatment using twisted file adaptive “TF Adaptive” Ni-Ti rotary system. Subjects and Methods: Twenty patients requiring endodontic treatment for necrotic single rooted teeth with periapical lesion were enrolled in this study. The selected patients were divided into two groups (10 patients each) according to the number of visits; Group І: single visit endodontic treatment and Group ІІ: two visits endodontic treatment. The root canals were prepared using the TF Adaptive system. In group I the obturation was done by modified single-cone technique in a single visit, while in group II the obturation was done in the second visit. Evaluation of postoperative pain at 24, 48 and 72 hours after obturation and periapical healing after 6 and 12 months was done. Results: There was no statistical significant difference between the two groups either in postoperative pain or in the periapical healing.Conclusion: Single visit and two visits endodontic treatment protocols were comparable regarding the incidence of postoperative pain and periapical healing

A literature review of single file NiTi rotary system in endodontics

The most important step in the success of the root canal treatment is the proper cleaning and shaping of the canal system. Cleaning and shaping means the removal of the entire pulpal tissue from the canal, so that there will be no residue left of any vital structure, that may cause any painful or infectious condition for the future. Some times there occurs difficulty in cleaning as well as shaping of the root canal in the posterior tooth or teeth, where the anatomy of the root is some what curved, and there occur difficulty in removing the vital tissue along with difficulty in achieving the accurate working length of the tooth. In this type of situation use of nickel titanium single file system is quite beneficial.

Evaluation of the Canal Transportation and Centering Ability of Different Rotary NiTi Systems in Simulated Curved Canals (A Comparative Study)

Evaluation of the Canal Transportation and Centering Ability of Different Rotary NiTi Systems in Simulated Curved Canals (A Comparative Study)

Cone-beam computed tomographic analysis of apical transportation and centering ratio of ProTaper and XP-endo Shaper NiTi rotary systems in curved canals: an in vitro study

BackgroundCleaning and shaping of the root canal system is an important step of endodontic treatment. Canal transportation is a common procedural error in preparation of curved canals. This study aimed to compare the canal transportation and centering ratio of two rotary files in curved canals using cone-beam computed tomography (CBCT).MethodsForty-four extracted human mandibular first molars with mature apices and 10° to 30° apical curvature were selected. The samples were randomly divided into two groups (n = 22) with similar curvature. The canals were prepared with ProTaper and XP-endo Shaper file systems according to the manufacturers’ instructions. The CBCT images were obtained using Cranex 3D CBCT scanner before and after root canal preparation, and canal transportation and centering ratio of the files at 3, 4 and 5 mm levels from the apex were calculated. Data were compared between the two groups using independent t-test at 0.05 level of significance.ResultsThe ProTaper Universal caused greater canal transportation and had lower centering ratio than XP-endo Shaper in both mesiodistal and buccolingual directions at all levels from the apex. The difference between the two groups regarding canal transportation was significant at all levels from the apex in buccolingual direction (P < 0.05) except for 3 mm from the apex (P > 0.05). The difference between the two groups regarding centering ratio was not significant (P > 0.05) in mesiodistal direction at all levels except for 4 mm from the apex (P < 0.05).ConclusionThe ProTaper Universal causes greater canal transportation in both buccolingual and mesiodistal directions than XP-endo Shaper.

The Influence of Single and Multiple NiTi Rotary File Systems on Prevalence of Postoperative Pain Following Root Canal Instrumentation Using Mechanical or Manual Glide Path Techniques

Purpose: The current investigation was carried out to estimate the influence of single and multiple NiTi rotary file systems on prevalence of postoperative pain following root canal instrumentation using mechanical or manual glide path techniques. Materials and methods: Forty participants with a sympotomatic irreversible pulpitis of mandibular molars were contributed in this randomized, controlled, clinical double blinded study. The participants were assigned into two main groups according to the gliding path system used then further subdivided into two subgroups according to the shaping system used. After access cavity preparation and working length determination, the glide path was prepared using either the PathFiles or the K-Files then the canal shaping was carried out using either the WaveOne Gold or ProTaper Next systems then the root canals were obturated. The postoperative pain was assessed by means of the modified visual analogue scale following 6, 12, 24, 48, 72 hours and 7 days then the data were collected and analyzed. Results: Postoperative pain was significantly higher after using the WaveOne Gold and the K-Files. Conclusions: Although all systems caused postoperative pain, the mechanical glide path along with the multi-file continuous rotational systems could be considered as a promising and reliable approach in preparing the root canals with less postoperative pain.

Evaluation of Gutta Percha removal from different niti rotary file system: An in vitro study

The main goal of endodontic retreatment is cleaning and shaping of the root canal with removal of old root filling material. Hand instruments and rotary instruments are mainly used for removing this filling material; as hand instruments are time consuming and tedious so we used rotary instrumentation for removal of gutta percha. The main aim of this study is to compare the relative efficacy of three different NI TI rotary instrumentation systems for removal of gutta-percha from root canal during endodontic retreatment. Materials and Methods: Sixty freshly extracted, single-rooted human anterior teeth were instrumented with K-files, and each root canal was filled with gutta-percha and AH Plus (Dentsply Detrey, Konstanz, Germany) sealer using lateral compaction. Specimens were then divided into three experimental groups with ten specimens each. The removal of gutta-percha was performed using Pro-Taper retreatment files, Mtwo retreatment files, and Edge file XR. The amount of root canal filling material remnant in the coronal, middle and apical thirds was measured using stereomicroscope. Result: The data was evaluated statistically using analysis of variance. Pro-Taper group was found to have less remnant filling material as compared to the other groups in coronal and middle thirds, but a significant difference was observed between edge file XR and Mtwo. Conclusions: It was concluded that EDGE FILE XR, rotary retreatment system proved to be the most efficient method of removing gutta-percha and sealer in comparison to the other two retreatment files and M-TWO retreatment files required less time to remove root filling material than the other instruments.

Evaluation of microcrack formation during root canal preparation using hand, rotary files and self-adjusting file in primary teeth: An in vitro study.

Background. Pediatric endodontics is a field with constant evolution, resulting in the shifting of paradigms from the use of conventional hand files to rotary files for biomechanical preparation in primary teeth. Biomechanical preparation plays a crucial role in the success of root canal treatment. Primary teeth need special attention since they differ from permanent teeth in root canal morphology. Cleaning and shaping of the canals damage the root dentin, leading to dentinal cracks. Newer techniques for root canal preparation, including Ni-Ti rotary files and SAF system, have been developed for use in pediatric endodontics to overcome the drawbacks of conventional methods. The present study compared dentinal defects formed by rotary systems in primary teeth.Methods. Eighty primary teeth were included. The teeth were decoronated with a diamond disc. All the roots were inspected for any pre-existing cracks or craze lines under transmitted light under a stereomicroscope. The specimens were then divided into four groups (n=20): group 1: control, group 2: hand files (HF), group 3: ProTaper files, and group IV: SAF files. The samples were instrumented according to the group they were assigned to. Results. The HF and SAF groups exhibited fewer microcracks. Dentinal microcracks were observed in roots prepared with rotary ProTaper files. There were significant differences between HF/SAF and rotary files (P <0.05). Conclusion. Stainless steel hand K-files and SAF instruments resulted in fewer dentinal damage than the ProTaper Universal files. SAF exhibited satisfactory results with minimal or no crack formation.

Comparative evaluation of dentin volume removal and centralization of the root canal after shaping with the ProTaper Universal, ProTaper Gold, and One-Curve instruments using micro-CT.

Background. The main goal of our study was to assess the volume of dentin removed and transportation in root canals using ProTaper Universal (PTU), ProTaper Gold (PTG) and One-Curve (OC). Ni-Ti rotary instruments in extracted human teeth using by micro-CT. Methods: Thirty human upper 1st premolar teeth with two separate root canals and sturdy, mature root tips were used in the present study. Specimens were decoronated and root length was standardized for micro CT scanning before root canal preparation done. The teeth were randomly separated into three categories (n = 10) according to the rotary NiTi system used for canal instrumentation, i.e., PTU (Dentsply, Maillefer), PTG (Dentsply, Maillefer), and OC (Micro-Mega SA). After root canal preparation, samples were scanned again on micro-CT by the same scanning parameters. Surface area, canal volume, structure model index (SMI), percentage of uninstrumented area and transportation parameters were obtained for each sample before and after micro-CT analyse. Results: No significant differences between the PTG and PTU in terms of the total volume of removed dentin, surface area and percentage of uninstrumented areas were found. However, regarding to parameters above, OC showed a lower efficacy than PTG and PTU in coronal section. Regarding canal transportation, PTG and OC showed lower mean transportation values at all levels. Conclusion: This paper demonstrated the root canal shaping abilities of the PTU, PTG, and OC NiTi file systems. The PTG and OC systems were associated less canal transportation and a better ability to preserve dentinal walls than PTU. There was no significance different between all rotary file systems for SMI values however, PTU and PTG showed greater canal volume and surface area change than OC file systems in coronal section.

TO COMPARE AND EVALUATE THE CYCLIC FATIGUE RESISTANCE OF THREE NITI ROTARY FILE SYSTEM-AN INVITRO STUDY

Aim: To compare and evaluate the cyclic fatigue resistance of three NiTi rotary file system&#x0D; Materials and Methods: Three NiTi rotary system (Hyflex EDM, Protaper Gold and One curve) were used in study . All files were tested in simulated constructed apparatus with angle of curvature 60o and radius of curvature 5mm.The rotary files were used in endomotor X smart (Densply) .All the instruments were utilized until fracture occurred, and then the number of cycles to failure (NCF) was calculated. The data were analyzed statistically using Annova test. The statistical significance level was set at P &lt; 0.05.&#x0D; Result: HEDM instruments had the highest cyclic fatigue resistance among all the other instruments (P &lt; 0.05). The one curve instruments had a significantly higher fatigue resistance than the Protaper gold instruments (P &lt; 0.05).&#x0D; Conclusion: Within the limitations of this in vitro study, it was found that the cyclic fatigue resistance was higher for the HEDM instruments than for the, Protaper gold and one curve instruments.&#x0D; Keywords: Cyclic fatigue resistance, heat‑treated NiTi instruments, HyFlex EDM, OneCurve

Evaluation of debris and smear layer formation using three different NI-TI rotary instrument systems: An in vitro scanning electron microscope study.

Aim: The aim of the study is to evaluate of debris and smear layer formation after using rotary ProTaper Universal, Twisted File, and XP Endo file systems under scanning electron microscope.Materials and Methods: Forty freshly extracted mandibular second premolar teeth were taken to decoronate at the cementoenamel junction to make the remaining root length 15 mm. Specimens were divided into four groups of 10 teeth each, Group I (control) – no instrumentation. Group II – ProTaper Universal rotary file (F2), Group III – twisted file (ISO size 0.25 and 6% taper), Group IV – XP Endo file (ISO size 0.25). During instrumentation, 5 ml normal saline was used as irrigating agent. Grooves parallel to the longitudinal axis of the root were made on the mesial and distal surface of each specimen to split it into two halves and examined under scanning electron microscope at ×1500 and ×5000 magnification. Photomicrographs were taken to evaluate debris and smear layer. Evaluation of photomicrographs was done using a score index.Results: One-way analysis of variance (ANOVA) was used to compare more than one means at a time. Tukey's critical difference followed by ANOVA was used to compare the mean values pair wise. P <0.05 was considered to be statistically significant. Among all the file systems, Group II showed maximum amount of debris (3.50 ± 1.109) followed by Group III (2.83 ± 1.238) and least amount was showed by Group IV (2.65 ± 1.122) at all levels (cervical, middle, and apical third). Among all the experimental groups, Group II showed maximum amount of smear layer (2.75 ± 1.149) followed by Group III (2.40 ± 0.982) and least amount of smear layer shown by Group IV (2.10 ± 0.841) at all levels (cervical, middle and apical third), the result was statistically significant (P < 0.05).Conclusions:At all the levels (cervical third, middle third, and apical third), among all the experimental groups, highest amount of debris and smear layer was formed by ProTaper Universal rotary file followed by Twisted file and least amount showed by XP Endo file system. In all the levels, control group showed highest amount of debris but least amount of smear layer.

Comparative Evaluation of Apical Transportation and Centering Ability of 4 NITI Rotary Systems with Different Metallurgy in Severely Curved Root Canals

Comparative Evaluation of Apical Transportation and Centering Ability of 4 NITI Rotary Systems with Different Metallurgy in Severely Curved Root Canals

Advancement of Mechanical Properties of Nickel-Titanium Rotary Endodontic Instruments by Spring Machining on the File Shaft

Nickel-titanium (NiTi) endodontic rotary instruments are used extensively in root canal procedures by both general dentists and specialists. However, their vulnerability to fracture is the major reason for clinicians’ concern regarding their use. The objective of this study was to investigate the potential effects of spring machining of the file shaft on the fatigue and torsional resistances of NiTi rotary instruments. Three types of NiTi rotary systems with (S) and without (NS) spring machining were used in this study (n = 15 each): a spring file (SPR; #25/.06, SPR-S, SPR-NS), a ProTaper Next X2 (PTN; #25/variable taper, PTN-S, PTN-NS), and a ProTaper Gold F2 (PTG; #25/variable taper, PTG-S, PTG-NS). Spring machining was adjusted on the 6 mm of each file system’s shaft via a laser cutting process. The number of rotation cycles until fracture (i.e., cyclic fatigue resistance), ultimate torsional strength, the distortion angle, and the toughness of each subgroup were estimated with specially designed devices. The results were analyzed using a paired t-test at a significance level of 95%. NiTi rotary instruments with spring machining exhibited a higher cyclic fatigue resistance than instruments without spring machining. The groups with spring machining exhibited a higher toughness and larger distortion angle than the groups without it (p < 0.05). In conclusion, spring machining on the shank of NiTi instruments may provide a stress-bearing area and attenuate the torsional and cyclic fatigue of NiTi rotary instruments.

Evaluation of apically extruded debris during the canal preparation using new heat-treated nickel-titanium files in curved canals.

This study compared the amount of apically extruded debris associated with different heat-treated Ni-Ti rotary systems during the preparation of curved root canals of mandibular molars. Sixty extracted human mandibular molars were selected. EdgeFile, K3XF, OneCurve (OC) and ROTATE files were used to prepare both mesial canals of teeth. The initial weight of each Eppendorf tube to be used was calculated using an analytical balance prior to instrumentation. After instrumentation, the tubes were then stored for 5days in an incubator at 70°C. Each tube was reweighed, and the weight of the dry extruded debris was established by subtracting the pre-instrumentation and post-instrumentation weight of the Eppendorf tubes for each group. All files caused apical extrusion of debris. There was no statistical difference between the ROTATE, EdgeFile, OC and K3XF systems (P>0.05). All the heat-treated Ni-Ti rotary systems led to similar apical debris extrusion during the canal preparation.

Comparative Assessment of the Shaping and Cleaning Abilities of M-Pro and Revo-S versus ProTaper Next Rotary Ni-Ti Systems: An In Vitro study

Objective: The aim of the present study was to compare the canal transportation, centering ratio, debris and smear layer score after using 3 rotary Ni-Ti systems, Revo-S (RS; Micro-Mega, Besancon Cedex, France) and ProTaper Next (PTN; Dentsply Tulsa Dental Specialties, Tulsa, OK) and M-Pro system( Guangdong, China, Mainland). Material and methods: Thirty nine mesiobuccal root canals of extracted lower first molars with 20˚ to 45˚ angle of curvature and were divided randomly into 3 groups of 13 samples each: group RS, group M-Pro and group PTN. Root canal transportation and centering ratio were evaluated at 3, 6 and 9 mm from apex using i-CAT CBCT (Hatfield, pennsylvania ,USA) before and after preparation.Thirteen Roots from each group were split longitudinally using diamond disc, by making a groove on buccal and lingual side of root without reaching the lumen of the canal.The root halves were examined under Scan Electron Microscope (SEM) by magnification x 1000 and x 4000 for debris and smear layer respectively The significance level was set at P ≤ 0.05. Results: There was no statistically significant difference in canal transportation, canal centering ratio, debris and smear layer score between the three tested groups. Conclusion: From the obtained results and within the limitations of this study, the following could be concluded:M-Pro Nickel Titanium rotary system had a negligible effect on root canal transportation which was similar to the ProTaper Next and Revo-S systems and no system was able to clean the root canal system completely.