Evaluation of the Smear Layer Removal Ability of Various Rotary Files with/without Chemical Agents on Primary Teeth: An In Vitro Study.

AIM: The aim of the current study was to assess the cleaning and smear layer removal efficacy of two different rotary files with or without chemical agents on primary teeth. MATERIALS AND METHODS: For the study, 90 extracted primary maxillary incisors without internal or external resorption and with at least two-thirds of complete roots were chosen. Then, based on the kind of instruments used to clean and shape the canals, they were randomly assigned to three experimental groups, each consisting of 30 teeth. Group-I: The canal was instrumented manually with K-files, Group-II: The canal was instrumented with Kedo-S files, Group-III: The canal was instrumented with Kedo-SG Blue files. After the canals were finally instrumented, 2 mL of QMixTM solution was used to irrigate 15 samples from each group. The samples were subsequently allowed to remain in the canals for 90 seconds in order to eliminate the smear layer. After that a stereomicroscope was used to assess the cleaning effectiveness. RESULTS: With irrigant solution, the highest mean value was found in manual K-files (2.86 ± 0.34), followed by Kedo-S files group (1.34 ± 0.26) and Kedo-SG Blue files (1.28 ± 0.18). Without irrigant solution, the highest mean value was found in manual K-files (2.92 ± 0.22) followed by Kedo-S files group (1.44 ± 0.18) and Kedo-SG Blue files (1.36 ± 0.14). There was a statistically significant difference found at all the three levels. CONCLUSION: On conclusion, the current study's findings demonstrated that irrigation solution was significantly more effective in cleaning and removing smear layers from pediatric rotary files than manual K-files. CLINICAL SIGNIFICANCE: The effectiveness of endodontic therapy depends on a successful chemomechanical preparation. The canals are instrumented using either hand files or rotary instruments; there are several irrigation and instrumentation techniques. In order to completely sterilize the canals, chemical agents are utilized for irrigation during instrumentation. Due to their numerous biological, antibacterial, anti-inflammatory, and antioxidant qualities, many natural compounds are also utilized as irrigants. How to cite this article: Abushanan A. Evaluation of the Smear Layer Removal Ability of Various Rotary Files with/without Chemical Agents on Primary Teeth: An In Vitro Study. J Contemp Dent Pract 2024;25(4):354-357.

Post-operative pain after root canal preparation with different apical finishing sizes a triple blinded split mouth clinical trial.

BACKGROUND: This is a triple-blinded, prospective split-mouth clinical trial. It is important to shed light on the effect of different apical preparation sizes regarding postoperative pain within the same patient with the same pulpal histological status. The aim is to compare and evaluate the severity of postoperative pain following apical enlargement with two different sizes after the IBF using the visual analogue scale. METHODS: Fifty "teeth" in 25 patients were assigned into two equal groups (25 per group) using E3 Azure rotary files; Group A was prepared two sizes greater than the Initial binding file (IBF) (the largest K file to bind at the actual working length) mesial canals, which were enlarged to 35#/0.04 and 40#/0.04 for the distal canals. Group B was prepared in three sizes larger than the IBF: 40#/0.04 for mesial canals and 45#/0.04 for the distal canals. On a modified VAS form, patients were questioned to indicate the degree of their pain and assisted in narrating their pain intensity during the following periods: 12, 24, and 72 h, and after a week. VAS data were non-parametric and analyzed using the signed-rank test for intergroup comparisons, Freidman's test, and the Nemenyi post hoc test for intragroup comparisons. The significance level was set at p < 0.05. RESULTS: showed that regardless of measurement time, enlargement of apical preparation was significantly associated with higher pain scores (p < 0.001). Within both groups, there was a significant reduction of measured pain score with time, with values measured after 12 and 24 h being significantly higher than values measured at other intervals (p < 0.001) and with values measured after three days being significantly higher than 1-week value (p < 0.001). CONCLUSION: The size of apical preparation had a significant effect on postoperative pain. TRIAL REGISTRATION NUMBER & DATE: NCT05847738, 08/05/2023.

Electrochemical Properties of Nickel-Titanium Rotary Endodontic Instruments.

INTRODUCTION: Nickel-titanium rotary endodontic files have been commercially available for decades, but more recent innovations have introduced heat-treated and surface-treated files. This study investigated the corrosion properties of various nickel-titanium files in normal saline and sodium hypochlorite (NaOCl). METHODS: Ten different file brands of size 40 with a 0.04 taper were subjected to electrochemical testing in 0.9% NaCl (saline) and 5.25% NaOCl at room temperature. The Open Circuit Potential (OCP) was observed for 1 hour followed by a cyclic polarization test from -300 to 700 mV and back to -300 mV (vs OCP). Nonparametric ANOVA and a pairwise comparison (P < .05) were used for statistical analysis of the OCP at 1 hour and the corrosion current (Icorr) obtained via the cyclic polarization test. RESULTS: Significant differences (P < .05) were found between files with respect to OCP and Icorr in both solutions. Nine files exhibited significantly greater (P < .05) Icorrs in NaOCl than in saline. Conversely, pitting corrosion was observed in the saline solution but not NaOCl. Weak and/or moderate correlations existed between OCP and Icorr measures in the 2 solutions. CONCLUSION: Significant differences in electrochemical properties were observed among the 10 brands of files. Overall, there was not a clear trend between conventional, heat-treated, or surface-treated files among OCP or Icorr in either solution.

Comparative Evaluation of Cutting Efficiency of Three File Systems-Kedo-SH Manual, Pedoflex Rotary, and Manual K File: An In Vitro Study.

Aims: The purpose of this study was to comparatively evaluate the cutting efficiency of Pedoflex rotary, Kedo SH manual file, and manual K file systems used in root canal instrumentation while performing pulp therapy of deciduous teeth with a stereomicroscope. Materials and Methods: Forty-five extracted primary human root canals were chosen, and following the removal of pulp tissue, the canals were dyed with Indian ink and left to dry for 2 h. The samples were randomly divided into three groups, Group A: Kedo SH manual file system (n = 15), Group B: Pedoflex rotary file system (n = 15), and Group C: Manual K files (n = 15). After root canal instrumentation, all the root canals were cleared to make them transparent. The teeth after clearing were observed under stereomicroscope and scored according to the amount of dye present in the root canals. The data were tabulated and statistically analyzed with SPSS version 16 using Chi-square, Kruskal-Wallis, and Dunn's test (post-hoc). Results: With regards to cutting efficiency, there was a statistically noteworthy difference among groups A and C [P = 0.000] and groups B and C [P = 0.000]. Furthermore, groups A and B did not differ statistically significantly [P = 0.950]. Conclusions: Cutting efficacy of the Pedoflex rotary files was seen to be superior to that of Kedo SH and manual K files. Clinical Significance: Rotary files in deciduous teeth have various benefits over manual files, resulting in a noticeable reduction in working time, which has aided in maintaining patient participation by reducing the risk for fatigue. We conclude that NiTi rotary devices result in a superior cutting efficiency and, as a result, greater clinical success.

Volumetric Analysis of Various Pediatric Rotary Files in the Preparation of Primary Root Canals Using Cone-beam Computed Tomography.

Aim: This study was planned to evaluate and compare the cleaning efficacy of three pediatric rotary files with the standard Protaper adult file system in primary teeth using cone-beam computed tomography (CBCT). Materials and methods: A total of 40 extracted deciduous second molars, with palatal/mesial roots having at least two-thirds of root length and an intact furcation area, were distributed randomly among four groups, with each group containing 10 teeth. Canal preparation of group I (Pro AF Baby Gold), group II (Kedo SG Blue), group III (Prime Pedo), and group IV (Protaper) was done. Pre- and postoperative CBCT images were taken. The volumetric changes of the root canals were assessed and subjected to statistical analysis using Statistical Package for the Social Sciences (SPSS) version 16 and R Studio 3.1.1. Volumetric changes within the groups were analyzed using paired t-tests and between the groups using analysis of variance (ANOVA). Results: The comparison of mean volume difference between groups using ANOVA was statistically significant with F = 4.467, p = 0.002. A Tukey post hoc test revealed that group IV was statistically significant compared with groups I (p = 0.033) and III (p = 0.008) but was not statistically significant with group II (p = 0.170). There was no statistically significant difference in volumetric changes within the three pediatric rotary file systems. Conclusion: Protaper removed more dentin than all the pediatric rotary files, but it was not statistically significant over Kedo SG Blue. Among the pediatric rotary files, Kedo SG Blue removed more dentin than Pro AF Baby Gold and Prime Pedo, but they were not statistically significant. How to cite this article: Nainer Chidambaram JV, Jayaprakash J, Arangannal P. Volumetric Analysis of Various Pediatric Rotary Files in the Preparation of Primary Root Canals Using Cone-beam Computed Tomography. Int J Clin Pediatr Dent 2024;17(1):15-20.

Comparative evaluation of stress distribution against the root canal wall at three different levels using novel NiTi rotary files - A finite element analysis.

Background: Recent innovations in the physical and mechanical features of endodontic file systems have diminished the prospect of stress generation and fracture risk in novel endodontic files. Aim: The purpose of this research was to comparatively evaluate the stress distribution of recently introduced endodontic rotary files with distinct features and metallurgy at three different levels of the root canal wall by finite element analysis. Materials and Methods: Forty endodontic files were used in this experiment after being inspected through a scanning electron microscope for any surface deformities. Based on their metallurgy and design, the scanned files were divided into four groups, each with 10 samples: Group A-2Shape files, Group B-F360, Group C-One Curve, and Group D-TruNatomy. To assess the mechanical behavior of these files, the stress produced by computer-aided models of these instruments on the dentinal wall of a simulated root canal was numerically analyzed using ANSYS® 15 Workbench finite element software. Results: A one-way ANOVA was used to assess all the raw data with post hoc Tukey analysis, the Shapiro-Wilk test, and Levene's test. F360 files exerted the maximum stress on the dentinal wall, while TruNatomy files exerted the least stress at all the distinct levels of dentinal walls. Conclusions: There was no statistically significant variation in the stress generated between the four groups. Therefore, it can be concluded that improvements in rotary file design and metallurgy have the potential to reduce the stress during canal shaping and the risk of instrument breakage during clinical use.

Analysis of cyclic fatigue resistance of different endodontic nickel-titanium rotary instruments: An in vitro study.

Aims: The aim of this in vitro study was to compare the cyclic fatigue resistance of three different endodontic nickel-titanium rotary instruments using a dynamic testing device. Materials and Methods: Ten files each of ProTaper Gold (PG), Hyflex Electro-discharge Machining (HEDM), and TruNatomy (TN) were tested in a custom-fabricated dynamic cyclic fatigue testing device at 60° curvature having a radius of curvature of 5 mm. The number of cycles to the fracture (NCF) of each instrument was calculated and three continuous groups were compared by the Kruskal-Wallis test and Dunn post hoc test was used for pairwise comparison. Results: Cyclic fatigue resistance of HEDM was the highest, followed by TN. PG had the lowest among the three. Conclusion: Within the limitations of the present in vitro results, it can be concluded that HEDM files appeared to be suitable for shaping complex canals with the greater number of cycles before it fractures.

Effectiveness of Different Rotary Files Systems in Removal of Gutta-percha during Endodontic Retreatment with or without Solvents: A Comparative Study.

AIM: The purpose of the present study was to compare the efficacy of three different file systems in removing gutta-percha during endodontic retreatment with or without solvents. MATERIALS AND METHODS: The current study used 120 freshly extracted, single-rooted human mandibular premolars extracted for orthodontic procedures. The canal was prepared utilizing the step-back technique and obturation was done. The samples were allocated into three experimental groups at random, group I: Hedstrom Files, group II: D-RaCe rotary system, and group III: Mtwo retreatment files system. The three groups were again split into two subgroups of 20 samples each, i.e., with solvent and without solvent. Then, a stereomicroscope with a magnification of × 20 was used to examine the samples. The amount of GP and sealer left was measured in three sections: At apical third (1 mm above the apex), middle third (8 mm from the apex), and coronal third (2 mm below the cementoenamel junction). The obtained data were analyzed using parametric Analysis of Variance (ANOVA). p-values less than 0.05 were considered significant. RESULTS: The overall least debris on the dentinal surface was found in the middle third with/without solvent. The D-RaCe rotary system was 1.24 ± 0.11 and 1.44 ± 0.14, Mtwo retreatment files system was 1.38 ± 0.17 and 1.72 ± 0.09 and Hedstrom files was 2.08 ± 0.21 and 2.18 ± 0.16 respectively and A significant difference was found between the three different file system groups (p < 0.001). CONCLUSION: The current study concluded that, when combined with a solvent, the D-RaCe rotary retreatment system is more effective than the Mtwo rotary retreatment system and Hedstrom Files in removing gutta-percha and sealant from root canal walls. CLINICAL SIGNIFICANCE: When it comes to treating chronic infections, non-surgical retreatment is a more cautious method than periapical surgery. Retreatment should be performed efficiently and with appropriate instruments to ensure effective treatment.

Comparison of Cleaning Efficacy of Different Rotary Files in Primary Teeth-An In vitro Study.

Aim: The aim of the present study was to comparatively assess the cleansing efficiency of dissimilar rotary files in deciduous teeth. Materials and Methods: Forty-five deciduous anterior teeth that had been subjected to extraction were chosen for this research. The teeth were included if they had a minimum of 2/3rd undamaged root portions. Coronal entrée was completed using round diamond burs. All 45 samples were allocated at random to one of the following three groups: Group I: Control group in which the radicular canal was not subjected to any form of instrumentation, Group II: The radicular canal was subjected to instrumentation employing rotary ProTaper files, Group III: The radicular canal was subjected to instrumentation with rotary MTwo files. The samples were subjected to immersion in a succession of diluted ethyl alcohols to permit dehydration: With a change of solution every eight hours, the first 16 hours were spent in 70% alcohol, followed by eight hours in 80% alcohol, eight hours in 95% alcohol, and eight hours in 100% alcohol. The samples thus subjected to dehydration were cleared by immersion in methyl salicylate for six hours. Under a stereomicroscope with a 10x magnification, the root canals were examined by a person who was blinded to the groups in order to look for any traces of ink in the coronal, middle, and apical third of the canals. Results: In the control group, greater residual remains were present in the apical 3rd at 2.16 ± 0.08 followed by the coronal 3rd at 2.02 ± 0.14, and then in the middle 3rd at 1.88 ± 0.10. While using the ProTaper files, greater residual remains were present in the middle portion at 1.68 ± 0.16, followed by the coronal third at 0.94 ± 0.09, then the apical third at 0.98 ± 0.22. Greater residual remains were again noted with the MTwo files in the mid-portion at 1.44 ± 0.18, followed by the coronal part at 0.86 ± 0.10 and then the apical part at 0.82 ± 0.04. Differences among these groups were statistically significant with a P value < 0.001. Conclusion: The present study concluded that either of the file types used exhibited reasonably lower remnant score values in the apical third versus the middle/coronal thirds. Nonetheless, MTwo type files delineated superior capacity at removing debris versus the ProTaper file types at the apical level.

Assessment of Various Reciprocating System in the Extrusion of Debris from Curved Root Canals: An Original Study.

Introduction: The endodontic preparation depends largely on the file systems that are used in the canal preparations. The amount of the intracanal debris that is extruded from the apex may be influenced by the file systems. Hence, the present in vitro study evaluated the amount the debris that is extruded for the two file systems at different working lengths. Methods: Forty human mesiobuccal canals of the first molars were collected that were extracted for various causes. They were equally divided to four groups of Reciproc (full length), Reciproc (short by 1 mm), WaveOne Gold (full length), and WaveOne Gold (short by 1 mm). Routine crown-down technique was followed for the canal preparation with the intermittent irrigation. The extruded debris was weighed and compared for the significance. Results: The amount of the debris that was extruded weighed similarly in all the four groups with no significant variations. The Reciproc extruded lesser material than the WaveOne Gold. Conclusions: The file systems seem not to affect the debris extrusion irrespective of the files' physical properties. Further studies in a clinical setup are warranted.

Adaptive instrumentation of root canals in primary teeth using XP-endo shaper: a case series.

Dental caries is indeed the biggest cause of tooth loss, particularly in the primary dentition. In primary teeth with carious pulp involvements, endodontic intervention in the form of pulpotomy (removal of only the coronal pulp) or pulpectomy (removal of coronal and radicular pulp) is advocated. Pulpectomy can be laborious and time-consuming, especially when using traditional hand endodontic files to shape root canals. In paediatric dentistry, motorised nickel-titanium (Ni-Ti) rotary instrumentation has proved significant in enhancing the quality of pulpectomy. In primary dentition, however, these files may leave more than half of the root canals unaltered by instrumentation, just as they do in permanent dentition. The XP-endo® Shaper is a revolutionary heat-dependent endodontic file that uses an asymmetrical rotating motion to address the maximum area of the root canal space, resulting in anatomic root canal instrumentation. The case series describes the use of this novel XP-endo® Shaper file for anatomic root canal instrumentation in primary molars with irreversible pulpitis. The purpose is to demonstrate the efficacy and advantages of this cutting-edge endodontic treatment method. This case series can be an informative resource for other endodontic specialists by providing a practical illustration of how adaptable instrumentation can be utilised to successfully treat a patient. In conclusion, The use of the XP-endo Shaper® for pulpectomy demonstrated faster and instrumentation that was confined with the original shape of the canals, although further research is required to fully utilise these findings.

Comparative Evaluation of Root Canal Transportation and Centering Ability in Curved Mesiobuccal Canals of Mandibular First Molars after Instrumentation with Different File Systems-An In vitro Study.

Aim: To assess the canal transportation and centering ability in the mandibular first molars' curved mesiobuccal canals after instrumentation with file systems XP endo Shaper, self-adjusting File (SAF), Hyflex EDM, Pro Taper NEXT, WaveOne Gold, and K files with the help of Cone-Beam Computed Tomography (CBCT). Materials and Methods: Ninety recently extracted mandibular first molars with mesiobuccal roots that had a 25-30 degree canal curvature were assessed. Following preoperative CBCT scans, teeth were allocated randomly to six experimental groups of fifteen. After preparation with XP endo Shaper, SAF, Hyflex EDM, Pro Taper Next, WaveOne Gold, and K files, post-instrumentation scans were taken using same parameters as pre operative scans. At 3 mm, 6 mm, and 9 mm from the apex, samples were assessed for canal transportation and centering ratio. Results: Apical transportation was least for XP endo Shaper as compared to other groups except SAF and the results were statistically significant. K file showed the highest apical transportation toward the lateral wall of the root canal. XP endo Shaper was better in maintaining centering ability of middle and apical third of canal and SAF was better in maintaining centering ability of coronal third. Conclusion: In root canal preparation, least apical transportation and better centering ability with XP endo Shaper than other file systems compared. K file showed the highest transportation.

Evaluation of root canal cleaning efficacy of selfadjusting files, protaper rotary, and manual K-Files in primary teeth - An In vitro Comparative study.

Background: The success of pulpectomy depends on complete eradication of microbial load by cleaning and shaping the primary root canals that is difficult to achieve because of anatomical intricacy of primary pulp dentin complex. Numerous instruments were tried, however, they proved to be inadequate. Selfadjusting file (SAF) is a newer file system that facilitates less dentin removal with maximal cleansing of root canals. Aim: To evaluate and compare the in vitro root canal cleaning efficacy with SAF, Protaper Universal, and Hand K-files in primary teeth. Materials and Methods: Sixty extracted primary anterior teeth were randomly divided into three groups by lottery method. Access cavity was prepared, the canals were enlarged up to 20 K file, and an Indian ink was injected into each canal. Then the Group I (n = 20) was treated with SAF, Group II (n = 20) with Rotary Protaper Universal and Group III (n = 20) with Hand K-files and the root canal cleaning efficacy was evaluated based on the amount of Indian ink remaining in the canal walls under stereomicroscopy. Data were analyzed using Kruskal-Wallis one way ANOVA test and post hoc Tuckey test for intragroup and intergroup comparison, respectively. Results: A statistically highly significant difference was observed with SAF (mean = 1.5), Protaper (mean = 2.5), and Hand K-files (mean = 2.9). However, there was no significant difference in root canal cleaning efficacy with Protaper Universal and Hand K-files. Conclusion: The SAFs had shown superior cleaning efficacy compared with rotary Protaper Universal and manual K files.

Comparison of the Effects of WaveOne Gold, TruNatomy, and Conventional Hand Files on Remaining Dentin Volume in the Coronal Part of the Root and Preparation Efficiency in Mandibular Molars.

INTRODUCTION: The use of file systems that work with different principles in root canal treatment is becoming widespread. The aim of this study was to evaluate the remaining dentine volume in the coronal region of the root and preparation efficiency after the use of conventional hand files, WaveOne Gold; which works with reciprocating motion, and TruNatomy; which works with rotational motion in the root canal treatment of mandibular molar teeth. METHODS: All canals of permanent mandibular molars (n = 36) were used. Root canals in each group (n = 12) were prepared with conventional hand files, WaveOne Gold, and TruNatomy. The three-dimensional images were evaluated for remaining dentine volume in the coronal two-millimeter region of the root and change in volume of the entire root canal space. RESULTS: There was no statistically significant difference between the groups in terms of mean differences pre and postpreparation (P > .05). The mean differences after preparation were observed the most in the WaveOne Gold group and the least in the TruNatomy group in the coronal two-millimeter region of the root and entire canal volume, but the differences were not significant (P > .05, P > .05, respectively). CONCLUSIONS: Conventional hand files, WaveOne Gold working with reciprocating motion, and TruNatomy working with rotational motion, which are the file systems used in the study, are not superior to each other in terms of remaining dentin volume in the coronal two-millimeter region of the root and preparation efficiency in the entire root canal space in mandibular molars.

Evaluation of Apically Extruded Debris and Cleaning Efficiency of the Pediatric Rotary File System and the Manual Nickel-Titanium File System.

Background This study aimed to assess and compare the Kidzo pediatric rotary file system with the manual nickel-titanium (NiTi) K-file system used for preparing the root canal of primary mandibular second molars by measuring the total apically extruded debris utilizing a sensitive microbalance and assessing cleaning efficiency using a scanning electron microscope. Methodology A total of 46 mandibular second primary molars were instrumented using a pediatric rotary system (Elephant Kidzo, India) and a manual NiTi K-file system (Endostar, Poldent, Poland). The debris released from the apex was retrieved and dried in Eppendorf tubes that were weighed beforehand. The total extruded debris was determined using a digital electronic scale, following which the molar roots were vertically sectioned, and the canal walls were investigated at the apical, middle, and coronal levels by a scanning electron microscope for debris and smear layer. Results The Kidzo pediatric rotary file system extruded a lesser amount of debris than the manual Endostar file system, but the difference was statistically not significant. Regarding cleaning efficiency, the debris originating in the apical and middle regions by employing the rotary filing technique was significantly less (p < 0.05); however, at the coronal level, there were no notable differences. Conclusions The Kidzo pediatric rotary system produced less apically extruded debris than the manual system and demonstrated better cleaning efficiency.

Effectiveness of pediatric rotary, rotary and reciprocating instrumentations on bacterial load reduction in primary molars: an ex vivo comparative study.

This study aimed to evaluate the efficacy of intracanal Enterococcus faecalis reduction using pediatric rotary (EndoArt Pedo Kit Blue, EasyInSmile X-Baby and Denco Kids), rotary (ProTaper Next) and reciprocating (WaveOne Gold) file systems through microbiological analyses in primary molars. Seventy-five mandibular primary second molars were selected and divided into five instrumentation groups and a negative control group. After incubation, five roots were used to confirm biofilm formation on the root canals. Before and after instrumentation, bacterial samples were collected. The bacterial load reduction was statistically analyzed by using Kruskall-Wallis and Dunn post hoc tests at a significance level of 0.05. Denco Kids and EndoArt Pedo Kit Blue promoted higher bacterial reduction than EasyInSmile X-Baby systems. There was no difference in bacterial reduction between ProTaper Next rotary file systems and other groups. Among the single-file techniques, instrumentation with the Denco Kids rotary system showed a more significant bacterial load reduction than WaveOne Gold (p < 0.05). All systems used in the study reduced bacterial counts from root canals in primary teeth. Further studies are required to generate more information about the use of pediatric rotary file systems in clinics.

Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Instrumented With K3XF Rotary Files Using Different Tapers.

AIM: To compare the effect of different tapers of the K3XF file system on the fracture resistance of endodontically treated mandibular premolars obturated with a three-dimensional (3-D) obturation system. METHODOLOGY: For the study, 80 freshly extracted human mandibular premolars with single well-developed roots without any curvatures were taken and the tooth roots were wrapped in a single layer of aluminum foil, and they were placed vertically in a plastic mold filled with self-curing acrylic resin. The access was opened, and working lengths were determined. The canals were instrumented keeping an apical size of #30 by different taper rotary files: Group 1: un-instrumented (control group), Group 2: 30/.04, Group 3: 30/.06, Group 4: 30/.08 K3XF file system, and teeth were obturated using a 3-D obturation system, and access cavities were filled using composite. Both experimental and control groups were subjected to fracture load using a conical steel tip (0.5mm) attached to a universal testing machine to record force applied in newton until root fracture. RESULTS: Root canal instrumented groups showed lower fracture resistance than the uninstrumented group. CONCLUSION: Hence it could be concluded that endodontic instrumentation with increased taper rotary instruments caused a decrease in fracture resistance of the teeth, and biomechanical preparation of root canal system with rotary or reciprocating instruments caused a significant decrease in fracture resistance of endodontically treated teeth (ETT), thereby decreasing their prognosis and long-term survival.

Cyclic fatigue resistance of EdgeTaper Platinum, Protaper Gold, and TruNatomy Prime rotary files before and after autoclave sterilization.

Background: This in vitro investigation aimed to determine the influence of multiple autoclave cycles on the cyclic fatigue resistance of three heat-treated nickel-titanium (NiTi) files: EdgeTaper Platinum (ETP), ProTaper Gold (PTG), and TruNatomy Prime (TN). Materials: Sixty NiTi files, twenty of each NiTi file type: ETP 25/.06, PTG 25/.08, and TN 26/.04 were randomly divided into four equal subgroups (n = 5). The files for the control group were left un-autoclaved. Different autoclave sterilization cycles (one, five, and ten) were used for the other three groups. The files were then placed in a metal canal block and rotated according to the manufacturer's instructions until fracture. The length of the broken segment and the time taken for fracture were measured. The fractured surfaces were subsequently subjected to SEM imaging. The Kruskal-Wallis test was used to analyze the data, followed by Dunn-Bonferroni pairwise comparisons. Statistical significance was set at p < 0.05. Results: ETP showed significantly greater resistance to cyclic fatigue than TN in all autoclave groups and PTG after five autoclave cycles (p = 0.014). Fatigue resistance was not affected by the number of autoclaving cycles, except for ETP. After the first and tenth autoclaving cycles, they required significantly more rotations to failure than the non-sterilized files (p = 0.039 and p = 0.021, respectively). The fractured segments of the ETP files in these two groups were also longer than those in the control group (p = 0.010). Conclusion: The cyclic fatigue resistance of ETP was greater than that of TN in all tested conditions. Repeated autoclave cycles of sterilization improved the cyclic fatigue resistance of the ETP files only and did not affect the cyclic fatigue resistance of TN and PTG. However, the ETP files separated at a longer distance from the tip with increased autoclaving cycles.

Finite Element Analysis of Stress Distribution in Root Canals When Using a Variety of Post Systems Instrumented with Different Rotary Systems.

It is very important for clinicians to provide restorative treatments that provide durability for endodontically treated teeth. Trauma, occlusal premature contact, and features of teeth are some of the issues that can cause vertical root fractures (VRFs) in root canal-treated teeth. The aim of this 3-D study was to compare stress distribution on mandibular premolar teeth when using a variety of post designs instrumented with different rotary systems. Six mandibular premolar teeth were instrumented with the following tools: ProTaper Next, WaveOne (WO), Reciproc (R), ReciprocBlue (RB), F6-Skytaper, and TF-Adaptive. Teeth were scanned using cone beam computed tomography (CBCT) and the images were transferred to the Catia V5R25 software. Data were recorded in a stereolithography (STL) format. Four different post systems were used, fabricated from metal, fiber, zirconia, and titanium, respectively. Dentin, gutta, post, core, and crown models were added to the solid model. ANSYS V17.2 finite element analysis (FEA) software was used to determine stress distribution on each assembly. Finite analysis models were created that allowed for the calculation of stress distribution of 250-N loading at a 45° angle and vertical in relation to the roots. The maximum principal stress and von Mises values were higher under oblique loading on the roots. The F6-Skytaper and WO systems showed lower stress than other systems. The TF-Adaptive instrument showed higher stress distribution than the other models. Fiber and titanium posts showed lower stress than others. The F6-Skytaper, R, and RB instruments were found to be most effective in terms of displacement of the crown, resulting in the lowest stress values. Fiber and titanium posts showed better results than other post systems, while root canals instrumented with the F6-Skytaper and WO instruments were less likely to result in root fractures.

Comparison of obturation quality, instrumentation time and post-operative pain using manual K-files and pediatric rotary files in primary molars ­ a double blinded randomised clinical trial / Comparação da qualidade de obturação, tempo de instrumentação e dor pós-operatória usando Limas manuais K e Limas rotativas pediátricas em molares decíduos ­ um estudo clínico randomizado duplo-cego

Objective: to compare the quality of obturation, instrumentation time and post-operative pain after pulpectomy in primary molars using manual K-files, Kedo-S and Kedo-S Square rotary file systems. Material and Methods: a double blinded randomized control trial was conducted in 45 children, who were indicated for pulpectomy in any one of the primary mandibular molars. The canal preparation was done using either hand K-files, Kedo-S files, or Kedo-S Square files based on the groups assigned. The time taken for instrumentation was recorded using a stopwatch. The quality of obturation was evaluated using post-operative radiograph and post-operative pain was assessed with modified Wong-Baker Faces Pain scale. Results: instrumentation time was minimum in rotary Kedo-S Square files (53.23 ± 9.60 seconds) followed by Kedo-S files (82.70 ± 11.86 seconds). The preparation time was maximum with manual K-files (121.43 ± 20.18 seconds). Kedo-S square files provided a higher number of optimally filled canals (66.4%). All the three instrumentations equally showed the tendency to produce voids in the obturation. Rotary files Kedo-S Square followed by Kedo-S showed less post-operative pain compared to K-files. Conclusion: the use of pediatric rotary instruments for canal preparation during pulpectomy will result in better quality of obturation in reduced time with least post-operative pain (AU)

Objetivo: comparar a qualidade de obturação, tempo de instrumentação e dor pós-operatória após pulpectomia em molares decíduos usando limas manuais K, limas rotatórias Kedo-S e limas rotatórias Kedo-S Square. Material e Métodos: um estudo clínico randomizado duplo-cego foi conduzido com 45 crianças que foram submetidas à pulpectomia de algum molar decíduo indicado. A preparação do canal foi feita usando limas manuais K, ou limas Kedo-S, ou ainda Limas Kedo-S Square, com base nos grupos que foram selecionados. O tempo para a instrumentação foi registrado com um cronômetro. A qualidade de obturação foi avaliada por meio de uma radiografia após o procedimento e a dor pós-operatória foi avaliada com a escala de dor Wong-Baker Faces modificada. Resultados: o tempo de instrumentação foi mínimo para as limas rotatórias Kedo-S Square (53,23 ± 9,60 segundos) seguido pelas limas Kedo-S (82,70 ± 11,86 segundos). O tempo de preparação foi maior com as limas manuais K (121,43 ± 20,18 segundos). As limas Kedo-S Square promoveram um maior número de canais otimamente obturados (66,4%). Todas as três instrumentações mostraram igualmente a tendência em seproduzir vazios na obturação. As limas rotatórias Kedo-S Square seguidas pelas limas Kedo-S produziram menos dor pós-operatória comparadas às limas manuais K. Conclusão: o uso de instrumentos rotatórios pediátricos para a preparação do canal durante a pulpectomia resultará em melhor qualidade de obturação em tempo reduzido e com menos dor pós-operatória. (AU)