NiTi Rotary Files Research Articles

Evaluation of the stress generated during biomechanical preparation with nickel–titanium rotary endodontic file using finite element analysis

Introduction: Adequate biomechanical preparation of root canals is the essence of successful endodontic therapy. Roots with curved canal framework led to endodontic complexity. The hassles in the preparation of such complex canals have prompted the inauguration of nickel–titanium (Ni-Ti) instruments with properties of shape memory and superelasticity. They benefit root canal preparation with causing less aberration, yet intracanal separation due to fatigue remains a concern. The study was intended to evaluate and compare the stresses developed during biomechanical preparation with Ni-Ti rotary file in straight, moderate, and severely curved root canals using finite element analysis (FEA). Materials and Methods: Six real sizes, three-dimensional root models were designed in SolidWorks software with varying angles of curvature (2°–45°), and using the same software, ProTaper Gold F2 rotary file was developed. All the designed root models with the rotary file inserted into each model were subjected to FEA. ANSYS Software (version 17.2 Company, Commonwealth of Pennsylvania, USA) 2015 was used to simulating root canal shaping, and the stresses generated in all the root canal models were observed. Results: Highest mean stress was observed with 45° models which was 235.95 MPa, followed by a 30° simulated model showed 220.36 MPa and least stress of 125.22 MPa was observed with 2° models (P > 0.05). Conclusions: Increased canal curvature has definitely resulted in generation of more amount of stress.

Comparative Evaluation of Stress Distribution Against the Root Canal Wall at Three Different Levels by Using TruNatomy, XP-endo Shaper, F360, and 2Shape Files-A Finite Element Analysis.

The aim of this in vitro study was to assess the stress distribution of novel endodontic rotary files of different cross sections and metallurgy against the root canal wall at three different levels by using finite element analysis. A total of 60 novel NiTi rotary files were included in this study after being scanned for any surface deformities using a scanning electron microscope. The scanned files were assigned into 4 groups of 15 samples each based on their metallurgy and design: Group A-TruNatomy, Group B-XP-endo Shaper, Group C-F360, and Group D-2shape files. ANSYS® 15 Workbench finite element software (Canonsburg, Pennsylvania, United States) was used to numerically analyse the stress created by computer-aided models of these instruments on the dentinal wall of a simulated root canal to test the mechanical behaviour of these files. All data were analysed using one-way ANOVA with post hoc Tukey analysis, the Shapiro Wilk test, and Levene's test. The significance level was set at 5%. XP-endo Shaper files employed minimal stress on the surface of dentine during instrumentation, and F360 files exerted maximum stress on the dentinal wall. However, no statistically significant difference was found among the groups in relation to the amount of stress produced at the distinct levels of the root canal wall (p>0.05). There was no discernible difference in stress generation among the four groups in the current investigation. Therefore, it can be inferred that the upgrade in design and metallurgy of rotary files has the potential to downgrade the stress during the shaping of the canal and the menace of instrument breakage during their clinical usage.

Assessment of fracture resistance of mesial roots of mandibular molars prepared by NiTi rotary files of different tapers and alloys (A Comparative in-vitro study)

Assessment of fracture resistance of mesial roots of mandibular molars prepared by NiTi rotary files of different tapers and alloys (A Comparative in-vitro study)

Cyclic fatigue resistance of ProTaper gold and two replicalike rotary systems. An in vitro study

Introduction: As a new phenomenon in endodontics, it was observed that nickel–titanium (NiTi) rotary systems closely replicate the systems created by the original companies are manufactured and available in the market for clinicians. These replica systems are usually sold at lower prices than the original rotary systems, which attracted end-user clinicians. Although clinicians widely use these replica systems, their mechanical performance has not been evaluated in any scientific literature. The aim of the current study was to analyze the cyclic fatigue resistance of two lower prices replica NiTi rotary file systems involving 0.25/0.08 v of MG3 Gold Perfect® and V TAPER Gold Fanta versus ProTaper Gold®. Materials and Methods: The NiTi rotary instruments (n = 15 of each) were allowed to rotate continuously, in dynamic mode, in a simulated stainless steel canal having a 6 mm radius and 60° curve till fracture. Time to fracture (TTF) in seconds was recorded, and the number of cycles to failure (NCF) was calculated. TTF and NCF were compared between the three groups. Results: The V TAPER Gold Fanta instrument showed significantly longer TTF than the ProTaper Gold instrument (mean = 1130.30 ± 244.42 vs. 354.30 ± 52.01 s), accounting for a three-fold difference in NCF (mean = 6593.42 ± 1425.79 vs. 2066.75 ± 303.40 cycles, P < 0.001). However, an insignificant difference in TTF was observed between the MG3 Gold Perfect® and ProTaper Gold instruments (P = 1.00). Conclusions: The V TAPER Gold Fanta instrument is a safe and cost-effective alternative to the ProTaper Gold instrument.

Impact of Different Kinematics on Debris Extrusion Using Two Different Full Sequences Rotary NiTi Files: An In Vitro Study

Impact of Different Kinematics on Debris Extrusion Using Two Different Full Sequences Rotary NiTi Files: An In Vitro Study

Effect of NaOCl on cyclic fatigue resistance.

The impact of 5.25 percent NaOCL on the resistance offered by TruNatomy, Hero Gold and ProtaperGold against cyclic fracture as against the treatment of NiTi rotary files with distilled water is of interest to dentists. Inside the stainless steel blocks, man-made canals were created for the purpose of testing the cyclic fatigue. 60 endodontic files were taken as study specimens. It was observed that values of number of cycles to fracture in NaOCl among three file systems were in the order of TruNatomy (1053.50 ± 134.81)>Hero Gold (652.66 ± 58.66) > ProtaperGold (494.50 ± 47.69). The TruNatomy file system reflected greatest cyclic fatigue resistance. It was also found that cyclic fatigue resistance in NiTi rotary files studied here is not hampered by 5.25% NaOCl.

Efficiency and complications in root canal retreatment using nickel titanium rotary file with continuous rotation, reciprocating, or adaptive motion in curved root canals: a laboratory investigation

BackgroundIt is currently unknown whether rotary file motion affects the best outcome of root canal retreatment. This experimental study compared the efficacy, efficiency, and complications of single-use NiTi rotary files using continuous rotation, reciprocating, and adaptive motions in root canal filling removal in curved root canals. Reciproc blue R25 was used with reciprocating motion (RB), VDW.ROTATE retreatment files with continuous rotation (VR), and ProTaper NEXT X2 with continuous rotation (PTNc) or adaptive motion (PTNa).MethodsForty mesial root canals of extracted mandibular first and second molars with an angle of curvature between 20°–40° and a radius of curvature between 5 and 10 mm were collected. The specimens were instrumented and obturated with gutta-percha and AH Plus sealer using the continuous wave of condensation technique. The specimens were randomly divided into 4 retreatment groups (n = 10), RB, VR, PTNc, and PTNa. The percentage of root canal filling removal in each group was analyzed using Micro-Computed Tomography (µCT). The motor running time, total time, root canal complication, and instrument complication were recorded and statistically analyzed (p-value < 0.05).ResultsThe pre-operative root canal curvature and root canal filling volume were comparable among groups. The percentage of root canal filling removal from the whole canal in the PTNc, RB, PTNa, and VR group was 98%, 96%, 95%, and 93%, respectively. A significant difference was observed between the PTNc and VR groups for the whole canal and the apical-third part. The motor running time and total time were significantly different between the groups. Instrument fracture was observed at 40% in the VR and 20% in the PTNa group, but none in the RB and PTNc groups.ConclusionsThe ProTaper NEXT X2 with continuous rotation and RB files can be used with high efficacy and efficiency in curved root canal retreatment. Continuous rotation is more efficacious and efficient than adaptive motion when using the NiTi rotary file. Single file retreatment can be used in small canals with high efficacy, cost-effectiveness, and less time consumption.

Factors Affecting the Cyclic Fatigue of Heat-Treated NiTi Rotary File: A Review

Clinicians face a major problem when a Nickel-Titanium (NiTi) rotary endodontic instruments fracture occurs inside the canal during treatment. It is time consuming for removal of these separated instruments, in addition to its technical difficulty. So for these reasons it is important to reduce the risk of file fracture. As a sequel, several attempts have been made to improve the mechanical features of NiTi rotary files, like changes in speed of operation, changing the geometric and dimensional characteristics, and several different metal treatments. The revolution of new heat-treated NiTi instruments opens a new era for basic, clinical and scientific research. This article concerns mostly with environmental and heat-treated factors, irrigation and type of rotation and their effects on heat-treated NiTi instruments found in most studies.

Evaluation Of the Antibacterial Effect of MTAD And Vanillin Against Root Canal Bacteria Running Title: MTAD And Vanillin Against Root Canal Bacteria

Objective: Comparison of the effectiveness of Bio pure MTAD (mixture of Doxycycline, citric acid and a detergent) versus vanillin(V) as an endodontic aqueous solutions for tested canals infected with E. faecalis and S. Mutans. Materials and methods : Fourty human extracted lower bicusped teeth (single-rooted) unit at the cementoenamel junction (CEJ) were decoronated. Thereafter, the teeth were prepared with Protper NiTi rotary files till (F3 [30/.06). Then samples are often divided into “2” main groups (18/each), infected by bacteria and incubated in brain heart infusion (BHI) for forty-eight hours at “37°C”. Then the teeth were sub-divided into three groups(N=6) according to the irrigation protocol (MTAD, V, and Distilled water”DW”, which was the control group ”Gp.”).-ve control(N=4). Dentin chips were removed from the canals by sterile low-speed handpiece spherical bur, transfered to BHI, then cultured to count the growing colonies which were recorded as colony forming unit (CFU).Results : Siginficant differences were found in the bactericidal efficacy of (Bio pure MTAD, V and DW) irrigations. Conclusion:Bio pure MTAD had the maximum antibacterial efficacy on E.faecalis and S. mutans as compared to vanillin and DW. Significance and impact of the study: Understanding the mode of action of natural antimicrobials(V) on endodontic therapy may facilitate their application as natural endodontic solutions, particularly for their potential use in endodontic irrigation protocol employing multiple hurdles.Additionally compared these natural compound with artificial one like MTAD and so on.

Comparing the EdgeFile X3, GenEndo, HeroGold, and ProTaper Gold Rotary Instruments Regarding the Effect of Different Concentrations and Temperature of NaOCl on Cyclic Fatigue Resistance.

This research was carried out with the objective of comparison between GenEndo, Protaper Gold, Hero Gold and EdgeFile X3 regarding the effect of different concentrations of NaOCl. About 720 study specimens were included in the study. They were divided into four groups. Each group consisted of 180 files. Group A: GenEndo, Group B: Protaper Gold, Group C: Hero Gold, Group D: EdgeFile X3. Each group of instruments were further subdivided into nine subgroups (n = 20 for each subgroup). Testing of the cyclic fatigue was carried out in artificial canals which were prepared inside the blocks of stainless steel. The stainless steel blocks with artificial canals were established in a receiver that was packed with experimental solutions like distilled water, 5.25% NaOCl and 2.5% NaOCl. The adjustment of temperature was done at 25, 37, and 60°C. The rotation of the instrument was carried out inside the artificial canal as per the instructions of the manufacturer. The instrument was rotated until it got fractured. The time taken by the instrument to fracture was recorded in seconds. The number of cycles to fracture (NCF) was analyzed with the help of the equation (NCF = time to fracture × rpm/60). Surfaces at the site of fracture were examined with the help of a scanning electron microscope (EVOLS10, ZEISS) at magnification (300x and 2000x). It was noticed that there was a statistically significant increase in cyclic fatigue when sodium chloride was used as an endodontic irrigant instead of distilled water. The increase in cyclic fatigue was also observed when 5.25% sodium chloride was used instead of 2.5% sodium hypochlorite. Cyclic fatigue increased on change in temperature from 25 to 37°C and from 37 to 60°C. The difference was statistically significant (p < 0.05). It was observed that resistance against cyclic fatigue on treatment with different irrigation solutions at different temperatures was in the order of GenEndo > Protaper Gold > Hero Gold > EdgeFile X3. The resistance against cyclic fatigue in new NiTi rotary files can be affected significantly by different concentrations of sodium hypochlorite irrigant solution and the GenEndo rotary endodontic instrument has the maximum resistance against cyclic fatigue. Irrigation of the root canal with irrigants, such as sodium hypochlorite (NaOCl) has been recommended strongly. NaOCl is used in the range of 0.5 and 6.5% concentration owing to its antimicrobial activity and tissue dissolution activities, particularly at higher temperatures. It has been postulated that fatigue of rotary endodontic instruments can be influenced by adjoining medium and their concentration.

An In Vitro Comparative Study of the Push-out Bond Strengths of Various Endodontic Sealers to Radicular Dentin.

The bond strength of an endodontic sealer to the root dentin is an important factor in maintaining the integrity of the root canal seal. The present study aimed to assess the push-out bond strength of three endodontic sealers used with the single-cone obturation technique. The root canals of 40 central maxillary incisors were instrumented using ProTaper Universal NiTi rotary files. The roots were divided into 4 groups (N = 10) according to the type of root canal sealers: Group 1 (control group): AH Plus/Gutta-percha lateral condensation technique (LC); Group 2: AH Plus/Gutta-percha single-cone technique (SC); Group 3: GuttaFlow 2/SC; Group 4: Realseal SE/SC. After obturation, each tooth was prepared for push-out assessment. The total and sectional push-out bond strengths were measured and statistically analysed. Furthermore, failure modes were identified microscopically. The results indicated that samples in the first group showed the highest total and sectional bond strengths. Samples from other groups showed statistically similar total bond strengths. The highest sectional bond strength was found mainly in the apical root sections. Cohesive failure was predominant for the first group, whereas adhesive failure was predominant in the other groups. It could be concluded that the dentin bond strengths of the tested sealers used with the single-cone technique were nearly similar but lower than those of AH Plus/LC. The highest sectional bond strength was observed in the apical thirds. The failure mode was mostly cohesive for AH Plus/LC and adhesive for sealers used with the single-cone obturation technique.

Cyclic fatigue in endodontics: A bibliometric analysis

The aim of this study is to measure the effects and relationships of cyclical fatigue in scientific studies with bibliometric analysis methods in the field of endodontics, and to identify the main trends supported by visualization.Studies on "cyclic fatigue" in the field of endodontics were searched in Web of Science (WoS) and Scopus academic databases on 30 August 2022, including publications for 2022. The Pandas Library, one of the Python libraries, was used to compile the data obtained from two different data sources, the Biblioshiny program was used in the analysis of the data, and the Tableau program was used to visualize the data.As a result of the first search on the WoS, 554 articles were reached. If the same search strategy in the PubMed database was searched, 452 articles were reached. By using PubMed ID numbers of the articles in the data set downloaded from the PubMed, 364 more articles were found by searching the WoS again. By combining both data sets, duplicates were extracted and 682 articles were obtained from the WoS database. As a result of the scans, a total of 905 articles were reached, including 682 articles in the WoS and 223 articles in Scopus. Since it is assumed that any article can be indexed in more than one data source, duplicate data control were performed in the combined data set, and it was determined that there were 171 duplicate data points deleted from the data set. As a result, 734 studies were obtained.It is seen that the effort of endodontists to develop new formations and designs of NiTi rotary files in order to facilitate the cleaning and shaping of root canals during root canal treatment, and the number of articles on this subject continues to increase.

Endodontic retreatment of mandibular molars with the presence of missed middle mesial root canals: An important clinical lesion

Aim: Untreated root canals may have a direct impact on root canal treatment (RCT) outcome. The aim of this case report is to describe the nonsurgical root canal retreatment of two mandibular first molars in a patient's mesial roots that had previously missed middle mesial root canals (MMC). Methodology: A 14-year-old female was referred to the our clinic with the complaint of pain in the posterior areas of the right and left mandibula. During the examination, previous RCTs [teeth 36 (mandibular left first molar) and 46 (mandibular right first molar)] were observed. Besides, these teeth have periradicular lesions in the mesial roots probably due to unsuccessful previous treatment. Nonsurgical retreatment was suggested and accepted. Access cavities were prepared and the unnoticed MMCs were detected at the isthmus connecting both mesiobuccal and mesiolingual canals. All the root canals were shaped with NiTi rotary endodontic files. During the shaping, the root canals were irrigated copiously with NaOCl, EDTA, clorhexidine, and saline solutions under a certain protocol. Calcium hydroxide was used for intracanal dressing. Gutta-percha and a resin-based root canal sealer were used for filling. Coronal restorations of the teeth were completed with a composite resin. Conclusion: At follow-up examinations after 3-, 6-, and 12-months, the teeth were asymptomatic and radiographically showed repair of the lesion. Healing was achieved without any need for further endodontic surgical intervention. How to cite this article: Başoğlu A, Harorlı H, Er K. Endodontic retreatment of mandibular molars with the presence of missed middle mesial root canals: an important clinical lesion. Int Dent Res 2023;13(2):99-103. https://doi.org/10.5577/idr.2023.vol13.no2.8 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Assessment the impact of operator experience on cyclic fatigue resistance in reciprocating and rotary NiTi files: a comparative study between dental students and pediatric dentistry specialists

Introduction: Devices reducing clinical practice time, and which get minimally affected by user experience are invaluable in pediatric dentistry. Additionally, knowing the fracture resistance of different nickel-titanium (NiTi) files for root canal preparation of primary teeth is important for treatment success. Thus, the present study aimed to compare the instrumentation time (IT) and fracture resistance of reciprocating T-endo MUST (TEM) and continuously rotating AF Baby File (ABF) NiTi files according to the use of pediatric dentistry specialists.Methods: According to their clinical experience level, 3 experimental groups (EG)s were formed namely: no experience, 2-years (less-experienced), and 10-years experienced pediatric dentistry specialists' groups. The fourth group was the control group (CG). In each EGs, 10 TEM (25/.06) and 10 ABF 20/.04, and 10 ABF 25/.04 NiTi file systems were used in 20 artificial resin teeth. Instrumentation time was recorded for each tooth. In the CG, the same number of files were not used for instrumentation. The files in all groups were subjected to a dynamic cyclic fatigue test, and the data were analyzed using the Kruskal–Wallis test at 5% significance level.Results: In all groups, TEM files showed a significant higher fatigue resistance as compared to ABF files. However, fatigue resistances were significantly lower in (EG)s both in TEM and ABF compared to (CG)s. The instrumentation time was found to be significantly lower in TEM compared to the ABF. Also, for both file systems, the experience level did not affect the fatigue resistance, and instrumentation time.Discussion: The experience level of the pediatric dentist did not affect the cyclic fatigue resistance of the reciprocating and rotating NiTi files, but the instrumentation time was lower for the reciprocating NiTi files.

Evaluation of shaping performance and surface changes of two different minimally invasive shaping file systems used in resin blocks

Aims: This study aimed to compare the shaping ability of T-endo MIS and TruNatomy (TRN) file systems in J-shaped resin root canals and to investigate the deformation of the files after two acrylic block preparation and two sterilization cycles.&#x0D; Methods: Forty acrylic blocks were numbered, then four file groups (n=10) were established: T-endo MIS glider (15.04) + T-endo MIS Finisher (25.04) (first and second usage) and TRN Glider (17.02) + TRN Prime (26.04) (first and second usage). Preoperative and postoperative images after the root canal preparation of simulated acrylic blocks were taken for each sample, and superimposed. The amount of resin removed from both the inner and outer walls of the canal to the level of 3, 5, and 7 mm from the apical point was measured, and the amount of transportation was calculated. Additionally, the deformation of the files was examined under a scanning electron microscope before and after usage and sterilization process.&#x0D; Results: Tip deformation of TRN files increased with the number of uses (p=0.007). With the second use, the surface deformation of the MIS files increased (p=0.015). There was no difference in cutting-edge deformation in either file type according to the number of uses (p&gt;0.05). There was no difference in transportation values between the MIS and TRN file systems at any level (p&gt;0.05). The file systems did not show a significant difference in the amount of transportation between first and second use (p&gt;0.05).&#x0D; Conclusion: When TRN (26.04) and MIS (25.04) NiTi rotary files were used twice on acrylic blocks, the amount of deformation did not differ. Both file types were similar in terms of transportation values.

Morphological Analyses of Effects of Endodontic Irrigant Solutions Using a Root Canal Model and an Immersion Model.

This study aimed to compare an experimental model simulating clinical root canal irrigation (root canal model) with a conventional experimental model immersing dentin sample to irrigants (immersion model) to evaluate removal of the smear layer and decalcification of the root canal dentin using sodium hypochlorite (NaOCl) and two different concentrations of ethylenediaminetetraacetic acid (EDTA) solution. Forty-five single-rooted extracted human teeth were prepared using a Ni-Ti rotary file. EDTA, NaOCl, and citric acid were used in the root canal models and the immersion models. After the irrigation protocol, root canal surfaces were observed under scanning electron microscopy. Residual smear and decalcification of the root canal dentin were evaluated objectively by measuring the percentage of the area occupied by visible dentin tubules, the number of visible dentin tubules, and the mean area of a visible single dentin tubule. Root canal and immersion models with the same irrigation protocol showed significantly different results for smear residues and decalcification of root canal dentin. In the root canal model, neither different EDTA concentrations nor the order of EDTA and NaOCl applications significantly impacted smear residues or decalcification of root canal dentin. Furthermore, no erosion of the root canal dentin surface was observed in any experimental groups in the root canal model using EDTA and NaOCl compared to intact dentin. Experimental design affected results for residual smear layer and decalcification of root canal dentin. The order of EDTA and NaOCl use and the concentration of EDTA did not affect results. EDTA and NaOCl irrigation did not cause erosion in the root canal model in this study.

The effects of chelation on the intratubular penetration depth of mineral trioxide aggregate.

The penetration depth and extent of mineral trioxide aggregate (MTA) crystallisation into dentinal tubules at 2, 4 and 6 weeks after chelation and MTA obturation were investigated. Standardised 12 mm human root specimens (45) were prepared with NiTi rotary files using 4% NaOCl irrigation. They were randomly allocated to three irrigants (n = 15: 4% NaOCl, 15% ethylenediaminetetraacetic acid or Edgemix) and obturated with sodium fluorescein tagged ProRoot MTA. One millimetre thick apical, middle and coronal sections were examined using confocal laser scanning microscopy to determine MTA penetration depth and area. Depths varied from 352 to 1821 μm at 6 weeks depending on section level and were unaffected by chelation. No differences (p > 0.05) were found in mean maximum penetration depth or dentine area (%) between the 3 irrigants at all time intervals. MTA mineralisation penetrated up to 90% of dentinal tubules and can extend to the cementum in roots with patent, non-infected tubules.

Effect of Immersion in Disinfectants on Cyclic Fatigue Resistance of Nickel-Titanium Instruments: An in Vitro Study.

Objectives: The current study aimed to assess the cyclic fatigue resistance of two nickel-titanium (NiTi) rotary files after immersion in 5% sodium hypochlorite (NaOCl) and Deconex. Materials and Methods: In this in vitro study, 90 new M3 Pro Gold size 25.06 and size F2 SP1 files were tested. Forty-five files of the same brand were randomly distributed into three groups (n=15) and submitted to the following immersion protocol for 5 minutes at room temperature: no immersion (control group), immersion in 5% NaOCl, and immersion in Deconex. The cyclic fatigue resistance of the files was then measured in a custom-made tester. Two-way ANOVA was applied to compare the cyclic fatigue resistance of SP1 and M3 NiTi rotary files based on the type of disinfectant solution. Post-hoc LSD test was used for pairwise comparisons and P<0.05 was considered significant. Results: Two-way ANOVA indicated a significant difference in the mean cyclic fatigue resistance of M3 and SP1 NiTi rotary files. The M3 files immersed in NaOCL displayed the lowest and the SP1 files immersed in Deconex showed the maximum cyclic fatigue resistance. The effect of type of disinfectant solution (P<0.001) and type of NiTi file (P<0.001) on cyclic fatigue resistance was statistically significant. Conclusion: The cyclic fatigue resistance of NiTi rotary instruments can be affected by immersion in disinfectants, and the specific type of file and disinfectant used will ultimately determine the extent of this impact.

OUTCOME EVALUATION OF ENDODONTIC TREATMENT WITH PROTAPER ROTARY INSTRUMENT SYSTEM ON MAXILLARY INCISORS

In recent years, thanks to the rapid advancement of science and technology and a better understanding of the anatomy of the root canal system, many new endodontic instruments and materials have been introduced with the desire to minimize complications in the process of preparing the root canal, help the cleaning and shaping process to complete well. It is noteworthy that the emergence of new endodontic files made of Nickel-Titanium alloy (NiTi files), which, according to the recommendations of manufacturers, make the preparation of root canals faster and more efficient, with a much simpler shaping technique than previous stainless-steel files. This is the topic that attracts great interest from clinicians. Therefore, it is necessary to conduct studies to evaluate these types of instruments. Over the years, there has been a lot of research on NiTi instrument systems carried out in the world, which mainly focused on the current types of rotary NiTi files. In Vietnam, although the NiTi instrument system appears a lot on the market and is increasingly employed by many dentists and endodontic experts, the amount of research on them is limited.&#x0D; Therefore, in order to contribute to more understanding and improve the effectiveness of endodontic treatment with niti rotary instrument systems we carry out the research: “Outcome Evaluation of endodontic treatment with Protaper rotary instrument system on maxillary incisors" with two aims:&#x0D; &#x0D; To evaluate root canal sealing results with cone beam computed tomography (CBCT)&#x0D; To evaluate the outcomes of maxillary incisor root canal treatment with the Protaper rotary instrument system.&#x0D;

Evaluation of cyclic fatigue resistance of nickel titanium rotary instruments: A systematic review and meta- analysis

A number of different thermomechanical treatments of NiTi have been developed to overcome some of the drawbacks of the traditional NiTi alloy, namely, separation and distortion of instruments. The present study analyzes the data on nickel-titanium instruments and their cyclic fatigue resistance. Online electronic data base such as PubMed, Cochrane and Google scholar through 31 January 2000 to 31 January 2020 with only English language literature. Clinical study of 9 article review &amp; stated that the Cyclic Fatigue Resistance Of Nickel Titanium Rotary Instruments tested in artificial blocks or canals ,tested with different NiTi rotary files between 200-500 rpm and accordingly torque under controled/uncntroled temperature in curved canls fracture occure. The findings of this systematic review and meta-analysis point to the possibility that the temperature at which the instruments are tested may affect the results of cyclic fatigue resistance on NiTi files with a different behavior depending on the heat treatment of the alloy and that an increase in the angle of curvature of artificial canals has a detrimental effect on the cyclic fatigue resistance. Reciprocal movement exhibited the best performance with regard to cyclic fatigue resistance. The thermal treatment of the instrument’s alloy, its cross section, and the glide path seem to influence the cyclic fatigue resistance. The cyclic fatigue resistance of instruments manufactured with the gold heat treatment is not influenced by room or intracanal temperature.