Stainless Steel Hand Files Research Articles

Comparative Analysis of Endodontic ISO Size 06, 08, and 10 Stainless Steel K-Files Used for Glide Path Procedures.

Small-sized stainless steel hand files are conventionally employed in root canal treatment procedures for canal scouting and for glide path establishment, owing to their superior flexibility and proficiency in navigating confined spaces. Given the diversity of brands available in the market, there exists potential variability in their physical characteristics, thereby influencing clinical performance. Consequently, this study aims to conduct a comparative analysis of the design, metallurgy, and mechanical characteristics among seven stainless steel hand file brands across ISO sizes 06, 08, and 10. A total of 315 new 25 mm length stainless steel hand files with apical sizes of 0.06, 0.08, and 0.10 from seven distinct brands were included in the study. A meticulous inspection of all instruments was undertaken to identify any structural deformations that might render them ineligible for the study. The design inspection involved the random selection of instruments from each group, which were examined under various microscopes, including a dental operating microscope, optical microscope, and scanning electron microscope. Furthermore, two instruments from each group underwent energy-dispersive X-ray spectroscopy analysis for elemental composition documentation. Mechanical tests were conducted to evaluate the instruments' resistance to lateral deformation (buckling) and their microhardness. Statistical analysis was executed using the nonparametric Mood's median test, with a predetermined significance level of 0.05. Regarding the instruments design, all files exhibited an active blade length ranging from 16 to 17 mm. However, variations were observed in the number of spirals, tip designs, and sizes, with the API K-File notably larger in sizes 0.06 and 0.08 compared to the other instruments. Despite uniform elements composition, differences in geometric features and mechanical properties were evident. Concerning buckling strength, the API K-File demonstrated superior performance across all tested sizes, while the Dentsply ReadySteel, SybronEndo, and Mani K-Files exhibited lower results (p < 0.05). In microhardness assessments, both the API and Oro K-Files displayed the lowest outcomes, with medians of 531 HVN and 532 HVN, respectively, whereas the SybronEndo K-File exhibited the highest microhardness (657 HVN). Despite similar metallurgical composition, the observed distinctions in geometric features and mechanical properties underscore the impact of the manufacturing process on the characteristics of glide path stainless steel endodontic files. These disparities may ultimately influence their clinical performance.

Comparative Evaluation of Different Retreatment Files for Gutta-percha Removal from Curved Root Canals Accessed with Novel Ultra-conservative Opening: An In-vitro Study

Introduction: In endodontic retreatment, gutta-percha removal must be done correctly in order to assure a successful outcome following failed procedures. The goal of this study was to compare the effectiveness of stainless-steel hand files with three different nickel-titanium rotary instrument systems for removing guttapercha using ultra-conservative access opening in curved canals. Aim: To compare the efficacy of different rotary instruments for removing obturating material from root canals with Ninja access in mandibular mesiobuccal moderately curved canals measured radiographically using Cone-beam Computed Tomography (CBCT). Materials and Methods: An in-vitro study was conducted in the Conservative and Endodontics department, Karnavati School of Dentistry, Karnavati University, Gandhinagar, Gujarat, India in the time period of June 2022 to July 2022. Forty extracted human mandibular molar teeth were accessed through Ultraconservative opening (Ninja Access). After preparing the root canals, they were sealed using gutta-percha and AH Plus sealer through lateral compaction. The teeth were then stored for one week. The samples were divided into four groups according to the rotary file used: Group I- Hedstrom Files; Group II- Pro taper Universal Retreatment (PTUR) Files; Group III- Neoendo Retreatment Files; Group IV- R-Endo Retreatment. The amount of remaining filling material after the retreatment procedure was checked with CBCT. The statistical analysis was performed using R statistical analysis software version 4.1.0 for windows. Results: In sagittal section, there was significant difference of residual filling material between the four file systems in middle third only (p=0.048) while significant difference was seen only in apical third in the coronal section (p=0.011). However, the three rotary retreatment files left significantly less remnants than Hedström files during removal of the gutta-percha. The time taken for retreatment was significantly higher for Hedström files (398.90±20.717) sec followed by R-endo retreatment files (274.30±14.407). Conclusion: H file was the least effective in removing guttapercha from the canals when compared to the other three file systems. The Neo-Endo rotary retreatment system was faster.

Microbial identification from traumatized immature permanent teeth with periapical lesions using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

BackgroundThis study aims at identifying the microbiota in traumatized immature permanent teeth with periapical lesions using Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).MethodsThe study included 16 immature maxillary central incisors with periapical lesions in 13 patients. Field decontamination and negative control samples were performed before and after access cavity preparation. Root canal samples were taken using sterile stainless-steel hand files following field decontamination. In-office inoculation and pure sub-cultures were performed. Bacterial isolates were prepared for MALDI-TOF MS (Bruker, Billerica, MA USA) analysis using the formic acid extraction method. A comparison of the prevalence of isolated microorganisms was done using a one-sample chi-square test. Comparisons between identified microbial species with the, cone beam computed tomography periapical index (CBCT PAI) scores and lesion volume were also conducted. The Chi-square test was applied to investigate the association between the categorical variables .ResultsOut of the forty isolates recovered from the 16 traumatized teeth included in the present study with the mean patients’ age of 10.93 ± 1.77, 37 isolates were reliably identified by MALDI-TOF MS. Twelve teeth (62.5%) were polymicrobial. The recovered bacteria belonged to five phyla, 15 genera and 25 species. Firmicutes were the predominant phylum (P < 0.001) over Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria. Gram positive bacteria were significantly more prevalent than Gram negative (p = 0.03). Facultative anaerobes were the most prevalent (P < 0.001) compared to the obligate anaerobes and the obligate aerobes. The latter were the least prevalent. Statistically, significant differences existed in the comparison between CBCT PAI scores according to bacterial gram staining.ConclusionTraumatized immature permanent teeth with periapical lesions showed a significant predominance of Gram-positive facultative anaerobes. MALDI-TOF MS provided accurate identification of numerous viable endodontic microbes.

Evaluation of Remaining Dentin Thickness of the Distal Portion of the Mesial Root of Mandibular Molar with Protaper Gold, Neoendo and Stainless Steel (SS) Hand K Files Using Cone Beam Computed Tomography for Analysis.

Aim: To evaluate the remaining dentin thickness of the distal portion of the mesial root of mandibular molar with stainless steel (SS) hand K files, ProTaper Gold and NeoEndo using cone beam computed tomography for analysis.&#x0D; Materials and Methods: Forty-five extracted human mandibular molars were collected. Teeth were randomly assigned to three groups (n=15). Samples were stabilized on blocks of wax. The working length for each sample was determined at 1 mm short from the apical foramen by using a ISO size #15 K file. Preparation was carried out according to the manufacturer’s instructions and canals were instrumented upto apically for each group. After each instrumentation, root canals were irrigated with 5.25% sodium hypochlorite solution followed by 17% EDTA solution. Final irrigation was done with normal saline. Post cleaning and shaping, cone beam computed tomography scans of all samples in the three groups were collected.&#x0D; Result: Protaper Gold and NeoEndo removed more dentin than SS hand file. As the mean remaining dentin thickness for SS K file, Neoendo and Protaper was 1.30, 1.05 and 0.80mm respectively&#x0D; &#x0D; Conclusion: Protaper Gold, NeoEndo and SS Hand files showed statistically significant difference in remaining dentin thickness of root canal length. Therefore, it was concluded that Protaper Gold file system showed a greater amount of removal of dentin as compared to NeoEndo file system &amp; SS Hand K files.

Evaluation of apical extrusion of debris during retreatment: R-Endo rotary instruments versus hand files

Aim: The aim of this ex vivo study was to compare the amount of debris extruded during retreatment using stainless steel hand files (Hedstroem files) and R-Endo Nickel Titanium rotary instruments. Methodology: Eighty single-rooted freshly extracted human mandibular premolars were divided into two groups consisting of 40 teeth each. Retreatment was performed with R-Endo (Micro-Mega, Besançon, France) and Hedstroem files (Dentsply, Maillefer, Ballaigeus, Switzerland). The experimental teeth were obturated with lateral condensation technique. Then, 1.5-mL Eppendorf tubes were used to collecting the material that was extruded during preparation by subtracting post-instrumentation weight from pre-instrumentation weight. Results: There were significant differences in the amount of debris extruded between the groups (p&lt;0.001). The amount of apical extrusion in the R-Endo group was determined to be less than in the hand instrumentation group. Conclusion: Within the limitations of this study, it might be concluded that all tested instruments resulted in apical extrusion of debris. During endodontic retreatment procedures, the hand files extruded a significantly higher amount of debris than the R-Endo. How to cite this article: Yırgın Akgül N, Haznedaroğlu F, Vardar Ç. Evaluation of apical extrusion of debris during retreatment: R-Endo rotary instruments versus hand files. Int Dent Res 2022;12(2):82-7. https://doi.org/10.5577/intdentres.2022.vol12.no2.6 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Evaluation of the Canal Transportation Following Glide Path Preparation with Different Rotary Systems: A Comparative Study.

Objectives Ideal root canal shaping might be more challenging particularly in cases with severely curved canals or complex anatomical variations. Glide path preparation is suggested as a critical step to achieve ideal canal preparation. The present study is aimed at evaluating transportation at different levels of the canal following glide path preparation by five different path finders. Materials and Methods The study was conducted on 100 S-shaped canal simulator blocks. Glide path was prepared in five groups including (1) Scout RaCe (#10 and #15, 0.02), (2) One G (#14, 0.03), (3) PathFile (#13 and #16, 0.02), (4) GPS (#15, 0.03), and (5) K file (#15, 0.02) (Control group). The first four groups were NiTi rotary instruments, while the last group was a stainless steel hand file. The aforementioned files were used after canal negotiation by a #10 stainless steel hand file. Before- and after-preparation photos were taken and were superimposed in Adobe PhotoShop CC 2019. Transportation measurements were conducted in Digimizer. Absolute canal transportation was calculated at 10 cross-sections. Intergroup and intragroup data analysis were conducted using one-way and repeated measures ANOVA tests, respectively, in SPSS 26.0. The significance level was set to 0.05. Results Although K file led to significantly more transportation in the apical and middle thirds (p < 0.001), rotary groups were not statistically different. In the coronal third, K files led to significantly more transportation compared to Scout RaCe and PathFile (p < 0.05). Conclusion Within the limitations of the present study, regardless of the recruited rotary system, glide path preparation using NiTi rotary instruments leads to less canal transportation compared to stainless steel hand files.

Evaluation of dentinal crack propagation, amount of gutta percha remaining and time required during removal of gutta percha using two different rotary instruments and hand instruments - An In vitro study.

One of the most important goal of non surgical endodontic retreatment is the successful removal of gutta percha and sealers from the root canal system. A variety of techniques have been recommended for retreatment procedures for the removal of gutta-percha and sealers with or without the help of adjunctive chemical solvents, by using stainless steel hand files or nickel-titanium rotary files, gate glidden burs, heated instruments, ultrasonic instruments, and lasers 1,3. The current advancements in the design of NiTi instruments have proved efficacious in the removal of filling materials from the root canal wall and various studies have also confirmed their cleaning ability and efficacy 4,5. Nevertheless, the use of rotary instrumentation can lead to the formation of dentinal cracks in the root canal dentin. Many researchers have reported the incidence of crack formation and propagation after the procedure with manual, rotary and reciprocating instruments. The behavior of rotary instruments in the generation of defects have been the point of greatest interest during many years 6. These dentinal cracks can be defined as defects with a complete crack line extending from inner root canal space up to the outer surface of the root when the tensile stress in the root canal wall exceeds the tensile stress of dentin 7. This study was conducted to investigate and to compare the amount of dentinal microcracks formation with various new instrumentation methods and conventional hand filing method. It also looks into amount of gutta-percha removed after retreatment from the canal and the time required for all the instrumentation technique. Sixty extracted human maxillary first molars with curved roots were mounted on addition silicone impression material incorporated in an aluminium hollow block, then instrumented using step-back preparation with 35 size K files. Obturation was done using gutta-percha with AH plus sealer. These were stored for 14 days and divided into three groups Mani GPR, Endostar Re Endo and H file and were subjected to retreatment procedures. Retreatment was considered complete when no filling material was observed on the canal wall and the canal was smooth and free of visible debris. The samples were examined under scanning electron microscope and the number of cracks were calculated. The percentage of root canal filling material and time taken was recorded. The data obtained were analyzed by using descriptive statistics, ANOVA (Analysis of Variance), chi-square test and Scheffe's post hoc test through SPSS for window (version 22.0). All the techniques showed similar amount of crack propagation, with no statistical difference between the group. Retreatment done using H Files required more time and removed less material. The coronal third showed less amount of gutta-percha remnants than the apical third in all groups. All the groups showed a similar amount of crack propagation. Less number of cracks were observed in the coronal one third and more amount of cracks were found at the apical third. Endostar RE Endo rotary instrument proved to be most effective and least time-consuming. Hedstrom Files required more time and removed less material.

The Effect of Glide Path Preparation on Root Canal Shaping Procedures and Outcomes.

The ‘glide path’ in non-surgical root canal treatment refers to a smooth radicular tunnel from the root canal orifice to its terminus. Its establishment is aimed at creating sufficient space to facilitate the subsequent and safer use of engine-driven nickel titanium (NiTi) shaping files. Glide paths were originally prepared using stainless steel hand files to, at least, a loose International Organisation for Standardisation (ISO) size 10 or larger. However, the advent of engine-driven NiTi instrumentation has led to the availability of many engine-driven NiTi glide path files. The aims of this review were to assess the effects of engine-driven and manual glide path preparation (GPP) on root canal shaping procedures and outcomes. An online search of the PubMed, Embase, Scopus and ScienceDirect databases was conducted and 32 studies were identified. The published literature suggests the use of engine-driven glide path files to be beneficial in maintaining the original root canal anatomy, reducing preparation time, decreasing apical extrusion of debris and causing less postoperative pain. However, there was no difference between engine-driven and manual GPP with regards to the physical strain exerted on the shaping files. Future research focused on clinical outcomes is needed to help ascertain the clinical benefits for patients.

What’s new for the clinician? - Excerpts from and summaries of recently published papers

Endodontic files are used to remove intracanal pulpal tissues, microbial biofilm, and toxic by-products and to develop a continuously tapering canal while maintaining the canal geometry that ultimately allows for the delivery of irrigating solutions and intracanal medicaments as well as the three-dimensional filling of the root canal system. Historically, stainless steel hand files have been used to perform canal shaping. However, these files are stiff and associated with increased operator fatigue, and when used in the preparation of curved root canals, the restoring forces of the files tend to return the file back to its original shape, resulting in canal transportation.

Mathematical validation of measurement of root fracture resistance: an in vitro study

BackgroundThe aim of this study was to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems.MethodsEighty human lower molars were selected and randomly divided into four groups (n = 20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentine volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05.ResultsThere were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P < 0.001).ConclusionsConsidering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.

Assessment of Practice of Endodontic Treatment Protocols among General Dental Practitioners in Pokhara, Nepal

Introduction: Endodontics is specialty field, but the majority of endodontic treatment in Pokhara is provided by the general dental practitioners. The aim of this study was to assess the practice of endodontic treatment protocols among general dental practitioners in Pokhara, Nepal. &#x0D; Materials and Methods: A cross sectional questionnaire based study was conducted among all the general dental practitioners working in various government, private hospital and clinic of Pokhara. Information about the materials and techniques used in endodontic treatment was collected and descriptive statistical analysis was done. &#x0D; Results: Out of 89 respondents, only 82 completely filled the questionnaires which were included in the study. Most general dental practitioners (96.34%) regularly treat single rooted endodontic cases. Only 10.97% occasionally use rubber dam during endodontic treatment. Most general dental practitioners (96.34%) used radiographic technique for working length determination. Ninety two percent used stainless steel hand files and step back was the choice of technique by 90.24%. Sodium hypochlorite irrigation and calcium hydroxide intra canal medicaments were used by 93.9% and 98.78% of general dental practitioners respectively. 75.6% used zinc oxide eugenol as root canal sealer and 95.12% obturated root canals with lateral compaction technique. The common complication encountered was mid treatment pain. They seem to overuse antibiotics in cases requiring endodontic therapy. Only 52.43% used autoclave for sterilization of endodontic files. About 92.68% felt the need of further endodontic training and 74.39% preferred post graduate program. &#x0D; Conclusion: This study indicates that many general dental practitioners of Pokhara are not following well acknowledged endodontic quality guidelines; hence there is a need for further endodontic training.

In Vitro Transportation of Curved Canals Following Glide Path Preparation by Path File and Scout RaCe Rotary Systems versus Manual Instrumentation Using Cone-Beam Computed Tomography.

Objectives:This study aimed to assess root canal transportation of curved canals following glide path preparation by PathFile and Scout RaCe rotary systems compared with manual instrumentation with stainless steel (SS) hand files using cone-beam computed tomography (CBCT).Materials and Methods:This in-vitro experimental study was conducted on extracted human mandibular first and second molars (n=51) with 25–45° canal curvature in their mesiobuccal root. All teeth underwent CBCT and were randomly divided into three groups (n=17). In group 1, a glide path in the mesiobuccal canal was created using SS hand files to the working length. In groups 2 and 3, after canal negotiation with a #8 SS hand file, a glide path was created with PathFile and Scout RaCe systems, respectively. The teeth underwent CBCT. Pre- and postoperative CBCT scans were compared to calculate the magnitude of canal transportation at 3, 6, and 9 mm from the apex. The results were analyzed using the Kruskal-Wallis and Freedman tests (P<0.05).Results:Manual instrumentation caused significantly higher canal transportation at 3 and 9 mm from the apex compared with rotary systems (P<0.05). PathFile and Scout RaCe were not significantly different at 3 (P=0.39) or 9 mm (P=0.99). No significant difference was noted in canal transportation among the three groups at 6 mm (P=0.15).Conclusion:Scout RaCe and PathFile cause less canal transportation than manual instrumentation with SS files when used for glide path preparation in curved canals, especially in the apical third.

Cone-Beam Computed Tomography Detection of Separated Endodontic Instruments

IntroductionThis study compared the accuracy, sensitivity, and specificity of different imaging diagnostic protocols, cone-beam computed tomography (CBCT) and digital periapical radiography (DPR), in identifying separated endodontic instruments in filled root canals. MethodsOne hundred eight root canals from 36 mandibular molars were prepared and obturated. Of these, 84 were filled without separated instruments, and 24 were filled with the presence of a separated instrument (stainless steel hand file or reciprocating instrument). Subsequently, different CBCT imaging protocols were acquired: i-CAT Classic (ICC) (0.25-mm isotropic voxel), i-CAT Next Generation (ICN) (0.125-mm isotropic voxel), and PreXion 3D (PXD) (0.09-mm isotropic voxel). Moreover, a DPR exam was obtained (08 mA, 70 kVp, and exposure time of 0.2 seconds). Two calibrated endodontists evaluated each image for the presence or absence of fractured files on a 5-point scale, ranging from definitely absent to definitely present. The accuracy, sensitivity, and specificity measures for each method were estimated. The data were evaluated by Fisher exact test and binomial test. ResultsNine instruments were identified in DPR (37.5%) and none in the CBCT protocols (P > .05). The type of instrument (stainless steel hand file or reciprocating instrument) did not influence the identification of the separated instrument (P > .05). This study showed that DPR is the most accurate and sensitive imaging technique, with 83.3% and 37.5%, respectively. ConclusionsDPR is the better imaging diagnostic exam to evaluate the presence of separated endodontic instruments inside a root canal in comparison with the ICC, ICN, and PXD tomographic protocols. However, most of the separated instruments were not identified.

Apical Transportation of Mesiobuccal Canals of Maxillary Molars Following Root Canal Preparation with Two Rotary Systems and Hand Files: A Cone-Beam Computed Tomographic Assessment

Objectives: This study aimed to compare the transportation of the mesiobuccal canal of maxillary molars following root canal preparation with HyFlex CM (HCM) and Edge Taper Platinum (ETP) rotary systems and stainless steel (SS) hand files using cone-beam computed tomography (CBCT).&#x0D; Materials and Methods: This in-vitro study was performed on 48 maxillary molars in three groups of 16. The teeth were mounted in acrylic blocks, and root canals were prepared using HCM in group 1 (up to #30/0.06), ETP in group 2 (up to F3/0.06), and SS hand files in group 3 (up to #30). CBCT scans were taken before and after root canal preparation. The amount of canal transportation was measured at 0, 3, 6, and 9mm from the apex. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests.&#x0D; Results: The difference in canal transportation at 0 and 6mm from the apex was significant between the HCM and ETP groups (P=0.031 and 0.023) but none of the systems showed any significant difference with hand files at 0- and 6-mm levels (P=0.10, 0.56, 0.22, and 0.50), respectively. At 3mm from the apex, no significant difference was noted among the groups (P=0.30). At the 9-mm level, the amount of canal transportation was not significantly different between HCM and ETP (P=0.83) but they showed significant differences with hand files (P&lt;0.001).&#x0D; Conclusion: ETP and HCM caused less canal transportation at the curvature of the mesiobuccal canal of maxillary molars compared to hand files. ETP showed superior efficacy in root canal preparation compared to HCM.

Simplify pulpectomy in primary molars with a single-file reciprocating system: a randomized controlled clinical trial.

To compare the clinical use of a single-file NiTi reciprocal system (sNiTi) to that of stainless steel hand file (SSH) instrumentation in primary tooth pulpectomy. A prospective randomized clinical trial was conducted in 34 healthy children aged 3-7years. Thirty-seven mandibular primary molars were randomly assigned to two groups: sNiTi and SSH. Instrumentation time, obturation time, quality of obturation, and 6- and 12-month clinical and radiographic outcomes were compared between the two groups. The median instrumentation time using sNiTi (3.23min) was significantly shorter than that for SSH (7.38min). Obturation times were not different. The quality of obturation was significantly different only in the mesial root canals; overfilling was seen more in the sNiTi group, while underfilling occurred more in the SSH group. At 6 and 12months, both groups showed comparable clinical and radiographic success regardless of the type of instrumentation. sNiTi shortens instrumentation time with comparable obturation time, overall quality of obturation, and clinical and radiographic outcomes with SSH. Pulpectomy is indicated to prevent premature loss of primary teeth with irreversible inflamed or infected pulp. However, it is complicated and time-consuming. sNiTi reciprocating system is an alternative to hand filing technique, avoiding multiple steps and simplifying pulpectomy procedures.

Comparative Study of Four Endodontic File Systems to Assess Changes in Working Length during Root Canal Instrumentation and the Effect of Canal Curvature on Working Length Change

IntroductionThe aim of this study was to compare a reduction in working length and area of canal enlargement resulting from instrumentation with Hedström (Kerr Dental, Orange, CA), K (Kerr Dental), ProTaper Next (Dentsply Sirona, York, PA), and TF Adaptive (Kerr Dental) files. The effect of the canal curvature on the working length and area of canal enlargement was also assessed. MethodsA total of 80 plastic canal models were used, 40 with a canal curvature of 10° and another 40 with a canal curvature of 30°. Instrumentation of 10 models with a 10° canal curvature and 10 models with a 30° canal curvature was performed using each of the file systems up to size 25. Working length measurements were taken before and after instrumentation with each file type and size. Twenty composite images were made from superimposition of pre- and postpreparation photographs, and the difference in area was calculated using ImageJ software (National Institutes of Health, Bethesda, MD). ResultsProTaper Next rotary files and TF Adaptive files produced the smallest reduction in the working length and the least canal enlargement followed by Hedström files and K files, respectively. The degree of canal curvature increased the working length reduction by a significant amount when K files and ProTaper Next rotary files were used, and the degree of curvature increased canal enlargement by a significant amount when K files were used. ConclusionsNickel-titanium rotary files produced more favorable results than stainless steel hand files in terms of maintaining a consistent working length and producing minimal canal enlargement. Hedström files performed significantly better than K files in terms of working length reduction and canal enlargement.

Use of the metal artefact reduction tool in the identification of fractured endodontic instruments in cone-beam computed tomography.

To evaluate the influence of the metal artefact reduction (MAR) tool in the diagnosis of fractured instruments in root canals of extracted mandibular molars, with or without root canal fillings. The root canals of 31 mandibular molars were divided into four groups: (i) the control group, without root fillings; (ii) the fracture group, without fillings and with fractured files; (iii) the fill group, with root filling; and (iv) the fill/fracture group, root filled and with fractured files. The following instruments were used as fractured endodontic instruments: stainless steel hand files, NiTi reciprocating files and NiTi rotary files. Each tooth was inserted in a dry mandible to obtain cone-beam computed tomography (CBCT) images using a CBCT OP300 3D Maxio (Instrumentarium Dental, Tuusula, Finland) and Picasso Trio (Vatech, Hwaseong, Republic of Korea), with and without application of the MAR tool. All images were evaluated by three radiologists for the presence or absence of fractured files on a 5-point scale. The diagnostic accuracy (area under ROC curve) was calculated. Image noise was measured in regions of trabecular and cortical bone and soft tissue. The comparison between the ROC curve values with the MAR tool enabled or disabled was performed using a t-test. A t-test was also employed for comparing image noise when the MAR tool was enabled and disabled. The significance level was set at 5%. The use of the MAR tool did not influence the diagnostic accuracy for identifying fractured endodontic instruments in root canals with and without fillings in both CBCT systems (P>0.05), nor did it influence the image noise (P>0.05). The MAR tool on these two devices did not increase the detection of fractured endodontic instruments and did not reduce image noise using extracted mandibular molars. Therefore, the MAR tool is not recommended for evaluation of fractured endodontic instruments in teeth with and without root fillings in mandibular molars.

Apical Transportation of Mesiobuccal Canals of Maxillary Molars Following Root Canal Preparation with Two Rotary Systems and Hand Files: A Cone-Beam Computed Tomographic Assessment.

Objectives:This study aimed to compare the transportation of the mesiobuccal canal of maxillary molars following root canal preparation with HyFlex CM (HCM) and Edge Taper Platinum (ETP) rotary systems and stainless steel (SS) hand files using cone-beam computed tomography (CBCT).Materials and Methods:This in-vitro study was performed on 48 maxillary molars in three groups of 16. The teeth were mounted in acrylic blocks, and root canals were prepared using HCM in group 1 (up to #30/0.06), ETP in group 2 (up to F3/0.06), and SS hand files in group 3 (up to #30). CBCT scans were taken before and after root canal preparation. The amount of canal transportation was measured at 0, 3, 6, and 9mm from the apex. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests.Results:The difference in canal transportation at 0 and 6mm from the apex was significant between the HCM and ETP groups (P=0.031 and 0.023) but none of the systems showed any significant difference with hand files at 0-and 6-mm levels (P=0.10, 0.56, 0.22, and 0.50), respectively. At 3mm from the apex, no significant difference was noted among the groups (P=0.30). At the 9-mm level, the amount of canal transportation was not significantly different between HCM and ETP (P=0.83) but they showed significant differences with hand files (P<0.001).Conclusion:ETP and HCM caused less canal transportation at the curvature of the mesiobuccal canal of maxillary molars compared to hand files. ETP showed superior efficacy in root canal preparation compared to HCM.

Dentinal defects induced by 6 different endodontic files when used for oval root canals: an in vitro comparative study.

ObjectivesTo compare the formation of dentinal defects using stainless-steel hand K-files (HFs), rotary files, reciprocating files, and Self-Adjusting File (SAF), when used for oval root canals.Materials and MethodsOne hundred and forty extracted human mandibular premolar with single root and oval canal were selected for this study. Oval canals were confirmed by exposing to mesio-distal and bucco-lingual radiographs. Teeth with open apices or anatomic irregularities were excluded. All selected teeth were de-coronated perpendicular to the long axis of the tooth, leaving roots segments approximately of 16 mm in length. Twenty teeth were left unprepared (control), and the remaining 120 teeth were divided into 6 groups (n = 20) and instrumented using HF (size 40/0.02), Revo-S (RS; size 40/0.06), ProTaper NEXT (PTN; size 40/0.06), WaveOne (WO; size 40/0.09), RECIPROC (RC; size 40/0.06), and the SAF (2 mm). Roots were then sectioned 3, 6, and 9 mm from the apex, and observed under stereomicroscope, for presence of dentinal defects. “No defect” was defined as root dentin that presented with no visible microcracks or fractures. “Defect” was defined by microcracks or fractures in the root dentin.ResultsThe control, HF, and SAF did not exhibit any dentinal defects. In roots instrumented by RS, PTN, WO, and RC files exhibited microcracks (incomplete or complete) in 40%, 30%, 55%, and 50%, respectively.ConclusionsThe motor-driven root canal instrumentation with rotary and reciprocating files may create microcracks in radicular dentine, whereas the stainless-steel hand file instrumentation, and the SAF produce minimal or less cracks.

Analysis of Apical Transportation and Canal Centering Ability During Root Canal Preparation by Using Cone-Beam Computed Tomography (in Vitro Study)

Objective: One of the goals of root canal preparation is to clean and shape the root canal system while maintaining the original configuration. So, it is essential to keep the instruments centered on providing a correct enlargement, Canal transportation is a common sequel caused by instrumentation, the purpose of this study was to evaluate the canal shaping efficacy of WaveOne® Gold, NiTiflex, and a stainless-steel K-files by CBCT.&#x0D; Methods: Sixty extracted curved single root premolars were selected, from Shorsh dental center and private clinic and divided into three equal groups. Before preparation, all samples numbered and scanned by CBCT. Then, the first group (n=20) were prepared with WaveOne Gold rotary file, the second group (n=20) were prepared by NiTiFlex hand file, and the third group (n= 20) were prepared by stainless steel files. Canal transportation and centering ability before and after root canal shaping assessed using CBCT and Adobe Photoshop CS3 Extended. The amount and direction of canal transportation in the apical third of each instrument determined in three axial sections of 2mm, 3mm, and 4mm from the apex, while the centering ability of each instrument determined in 5 axial sections of 2mm, 4mm, 6mm, 8mm, and 10mm from the apex. The three groups were statistically compared using one way ANOVA test.&#x0D; Results: It was reviled that there were no statistically significant differences in the magnitude of canal transportation between three groups (p &gt; 0.05) at 2 mm, 3 mm as well as 4 mm from the apex, while in group one (WaveOne Gold) showed significantly lower mean canal transportation as compared to other two groups. The centering ability was statistically significant in 2 mm axial section, WaveOne Gold had better-centering ability than NiTiFlex and Stainless steel hand file. While in other sections the difference was nonsignificant. &#x0D; Conclusions: The difference between the three groups was non-significant regarding transportation, while in apical part WaveOne Gold has better-centering ability than the other two groups.