ProTaper Gold Research Articles

Effects of Conservative Access and Apical Enlargement on Shaping and Dentin Preservation with Traditional and Modern Instruments: A Micro-computed Tomographic Study

IntroductionThis ex vivo study aimed to evaluate the shaping abilities and preservation of dentin with traditional and modern instruments after using sizes 25 and 40 in oval canals of mandibular incisors with conservative access. MethodThirty mandibular incisors with single straight oval canals were selected and assigned into 2 groups (n = 15) according to the instrument system used during preparation, Slim Shaper (SS) plus Apical Shaper (AS) and Protaper Gold (PG). The samples were subjected to micro-computed tomography before and after preparation with sizes 25 and 40. The shaping parameters evaluated included canal volume and surface area, amount of unprepared root canal walls, and reduction in pericervical dentin. ResultsCanal volume and surface area were significantly increased after enlargement with each instrument size (P < .01). The percentage of unprepared areas showed a significant intragroup decrease after using PG F2 and F4 or SS 3 and AS (P < .05). Intergroup comparison showed no significant differences. Pericervical dentin was reduced in all groups. The intragroup comparison only revealed a significant reduction (P < .01) between PG F2 and F4. In addition, a significant decrease in pericervical dentin (P < .05) was observed between PG F4 40/.06 and AS 40/.03. No significant differences were observed between PG F2 25/.08 and SS 3 25/.04. ConclusionIncreasing the instrumentation size from 25 to 40 significantly reduces the percentage of unprepared areas regardless of the system used. In addition, using a modern system with a regressive taper allows the maintenance of pericervical dentin without compromising shaping efficacy in the apical third of the mandibular incisors with oval canals and conservative access.

Effect of different glide path establishing systems on apically extruded debris in curved root canals – An in vitro study

ABSTRACT Aim: The aim of this study was to evaluate the effect of different glide path establishing systems when used along with WaveOne Gold (WOG) single-file reciprocating system and ProTaper Gold (PTG) rotary multifile system on apically extruded debris in curved root canals. Methods: Eighty extracted mandibular molar teeth with curved mesial roots were selected for this study. Specimens were randomly divided into eight experimental groups according to the root canal preparation (n = 10): Group 1 (WOG + H and K-file), Group 2 (WOG+ G-Files),Group 3 (WOG+ One G), Group 4 (WOG + ProGlider), Group 5 (PTG + Hand K-file), Group 6 (PTG+ G-Files), Group7 (PTG+ One G), and Group 8 (PTG + ProGlider). Roots were attached to preweighed Eppendorf tubes. All instruments were used according to the manufacturers’ instructions. During root canal preparation, 8 mL of distilled water was used for each specimen. Apically extruded debris was collected in Eppendorf tubes. After the completion of root canal preparation, Eppendorf tubes were removed from the specimens and stored in an incubator at 70°C for 5 days. Eppendorf tubes were weighed after evaporation to calculate the amount of extruded debris. The data were subjected to statistical analysis using one-way analysis of variance and post hoc Tukey’s test at a significance level of P &lt; 0.05. Results: A statistically significant difference was observed between the ProGlider and K-file groups. The ProGlider group was associated with significantly less debris extrusion than the K-file group for both the shaping systems used: WOG (P = 0.048) and PTG (P = 0.044). There was no statistically significant difference between NiTi rotary glide path files: ProGlider, G-Files, and One G files. All experimental groups caused apical debris extrusion. Conclusion: Among all mechanical glide path files tested, ProGlider showed the least debris extrusion which was significantly less than K-file. Glide path preparation using NiTi rotary files in combination with rotary shaping files (PTG) was associated with less apical debris extrusion than the rotary glide path files used along with reciprocating file (WOG).

Comparative evaluation of postoperative pain after single-visit endodontic treatment using protaper gold and hyflex electrical discharge machining rotary file system

Background: Endodontics has a widened range due to its increase in success rate and increase in lifespan of individuals. As of today, extracting the tooth has become a rare situation, and endodontic intrusion has become a custom. Although after having detailed knowledge about the internal anatomy of tooth, it is a must to know about the upcoming evolution of instruments as well as materials and complete knowledge regarding techniques of treatment modalities. Postoperative pain could leave a significant control on the quality of life, which will begin after completion of endodontic treatment having a range of 3%–58% cases. Materials and Methods: Twenty-six patients with irreversible pulpitis were selected for single-visit endodontics. The teeth were blindly assigned to two groups based on the instrumentation systems used: Group A (Protaper Gold) and Group B (Electrical Discharge Machining [EDM] Hyflex). Participants were asked to note the incidence of preand postoperative pain on the Visual Analog Scale at different time intervals. Results: The greatest mean pain in both Group A and B was found to be maximum in the first 24 h, with a significant reduction in pain at the subsequent observation time points of 48 h, 72 h, and 7 days. The least painful group was Group A, followed by Group B. Conclusion: In single-visit endodontics, both Protaper Gold and EDM Hyflex both may prove to be a better system, but according to statistics Protaper gold being slightly superior as it produces minimal postoperative pain, thus improving the overall acceptance of endodontic treatment.

Comparison of postoperative pain in single visit endodontics using heat-treated nickel − titanium file systems – A randomized clinical trial

Aim: The aim of the present study was to compare postoperative pain in single visit endodontics using heat-treated nickel − titanium file systems (ProTaper Gold, HyFlex EDM, V Taper 2H). Methods: Sixty patients requiring endodontic treatment in vital permanent lower molars with irreversible pulpitis were included in the study. Patients were divided into three groups each containing 20 patients: Group 1 teeth prepared with ProTaper Gold (Dentsply), Group 2 HyFlex EDM (Coltene), and Group 3-V Taper 2H (SS WHITE). Treatment was performed in a single visit. The severity of the postoperative pain was assessed by the Visual Analog Scale after 2, 4, 8, 12, 24, and 48 h. Data were analyzed using the Kruskal–Wallis tests. Results: There was no significant difference in the incidence of postoperative pain among the three groups. There was significant reduction in pain from preoperative till the end of 2 days, irrespective of the file systems used. When compared between the three groups. There was no significant difference in pain scores at different time intervals. When change in pain from preoperative to different time intervals was compared, there was no significant difference between all three groups. V Taper 2H files showed increased pain scores from 4 to 12 h, however, the pain reduced thereafter till 48 h with no significant statistical difference. Conclusion: Results of this in vivo study showed that there was no significant difference in the incidence of postoperative pain among the three groups.

Incidence of Postoperative Pain after Single Visit Root Canal Treatment using XP-endo Shaper, 2Shape and ProTaper Gold Rotary Systems: A Prospective Randomized Clinical Trial.

To evaluate the incidence of postoperative pain, treatment time and analgesic intake after single visit endodontic treatment of mandibular molars using XP-endo Shaper, 2Shape and ProTaper Gold rotary systems. 150 patients with irreversible pulpitis were scheduled for single visit root canal treatment. Teeth were randomly assigned to one of the three groups: ProTaper Gold (PTG; Dentsply Tulsa Dental Specialties, Johnson City, TN), 2Shape (2S; Micro-Mega, Besancon, Cedex, France) and XP-endo Shaper (XPES; FKG Dentaire, La Chaux-de-Fonds, Switzerland). Preoperative and postoperative pain was rated by the patients at the beginning of treatment and after 24, 48, 72 hours and 7 days on Heft Parker's visual analog scale (HP-VAS). Highest mean postoperative pain score was recorded in PTG (P<0.05), followed by 2S and XPES respectively at all time intervals. XPES exhibited maximum reduction from preoperative pain at 24 (48.67%) and 48 hours (96.90 %) with no pain at 72 hours. Treatment time was significantly least in XPES (P<0.05) followed by 2S and PTG; but no significant difference in analgesic intake was noted. XPES exhibited least postoperative pain at all time intervals and treatment time, followed by 2S and PTG rotary systems respectively. (EEJ-2022-04-053).

Shaping, and disinfecting abilities of ProTaper Universal, ProTaper Gold, and Twisted Files: A correlative microcomputed tomographic and bacteriologic analysis

ABSTRACT Aim: The purpose of this study was to assess the canal shaping ability and reduction of Enterococcus faecalis (E. faecalis) by ProTaper Universal (PTU), ProTaper Gold (PTG), and Twisted File (TF) systems, using microcomputed tomography (µCT). Methods: Distobuccal canals of 36 extracted human maxillary molars were inoculated with E. faecalis American Type Culture Collection 29212 for 28 days. Thirty-three specimens (three excluded due to contamination) were randomly divided into three groups with 11 specimens in each group, according to the instrumentation system that was utilized: PTU, PTG, and TF. Sterile distilled water was used as the irrigant during preparation. Paper points had been used to collect samples from the root canals both pre- and postpreparation, and bacterial quantification was done to examine the bacterial reduction. Pre- and postinstrumentation µCT scanning of roots were done to analyze the shaping ability. Results: After preparation, all three techniques significantly lowered the amount of E. faecalis while also significantly increasing the canal volume (P &lt; 0.001). Intergroup comparison of the % of bacterial reduction and uninstrumented area disclosed no significant differences (P &gt; 0.05), whereas the increase in canal volume of the PTU was significantly higher than PTG and TF, and that of the PTG was significantly higher than TF. Conclusion: It may be concluded, within the constraints of this in vitro study, that PTG and TF had better shaping ability than PTU, whereas no difference was found in their ability to reduce bacterial load.

Quantitative analysis of the obturation of oval-shaped canals using thermoplastic techniques.

One of the aim of root canal treatment is filling the root canals in a 3D way. It is not always possible to achieve due to the existence of anatomical variations. The obturation of oval canal usually provides great difficulties. Its complex anatomy can cause obstacles in instrumentation, irrigation and obturation. Aim: The main aim of this study is to quantify the area filled by gutta-percha, the area filled by cement and the area of voids present in oval canals, treated by thermoplastic filling techniques in comparison with the lateral condensation technique and observe the adaptation of the gutta-percha to the anatomy of the oval root canals according to the obturation technique. 80 mandibular incisors were selected. The teeth were instrumented with Protaper Gold® and divided into 4 groups of 20. Group 1 was filled with Thermafill®; group 2 with GuttaCore®; group 3 with continuous wave vertical condensation and group 4 with the lateral condensation technique. Two horizontal sections were cut at 5mm and 7mm from the apex and they were set in putty silicone. The samples were analyzed with a Leica DMS 1000 digital microscope and processed with Leica Suite for Windows XP. The area of gutta-percha, cement and voids and the percentages, of each one, were calculated. A statistical analysis was performed using the T-Student, ANOVA tests and Kruskal-Wallis tests. All thermoplastic techniques achieved a high percentage of obturation. The percentages of voids in group 4 were the highest. Statistically significant differences were found between thermoplastic techniques compared with lateral condensation. Thermoplastic techniques achieve better adaptation of the gutta-percha in the oval canals and low amount of cement and voids in the middle and coronal thirds respect to the lateral condensation group. Moreover, comparing termoplasthicized techniques among them, continuous wave vertical condensation got the lowest percentage of voids. Key words:Warm gutta-percha, thermoplastic obturation, oval canals, oval-shaped canals.

Apically extruded debris, canal transportation, and shaping ability of nickel-titanium instruments on contracted endodontic cavities in molar teeth.

Apically extruded debris, canal transportation and shaping ability were compared between contracted endodontic cavities (CECs) and traditional endodontic cavities (TECs) after instrumentation with XP-endo Shaper (XPS), ProTaper Gold (PTG), ProTaper for hand-use (HPT) and Hero Shaper. The CECs or TECs groups were sub-divided into 24 groups according to root canal morphology and nickel-titanium (Ni-Ti) instruments. The weight of apically extruded debris was calculated using the Myers and Montgomery model. Pre- and postoperative images of teeth were scanned using micro-CT and the three-dimensional models were constructed and compared. Under CECs or TECs, XPS and PTG produced less apical debris and formed less canal transportation than HPT and Hero Shaper (P < 0.05). XPS group under CECs extruded less apical debris than that under TCEs for round canals with curvature of 20°-35° (P < 0.05). The centering ratios of four tested instruments were higher under TECs than those under CECs (P < 0.05). The HPT and Hero Shaper had more transportation under CECs than that under TCEs (P < 0.05). No statistical difference was found regarding shaping ability among all the groups. Under CECs, XPS preserves the original root canal anatomy, meanwhile it produces less apical debris than the other instruments.

Effective management of mandibular second premolar with root anomalies

The enigma of successful treatment of mandibular second premolars with taurodontism has been explored for very long due to its rarity of occurrence. This case report aimed to enumerate the successful nonsurgical endodontic management of left mandibular second premolar #35 with three roots and taurodontism. A 34-year-old Saudi male patient with a noncontributory medical history was referred from the prosthodontic department for nonsurgical root canal treatment of tooth #35. Clinical examination revealed rotated clinical crown with caries related to tooth #35. Pulp sensibility cold test of the tooth showed no response, with the absence of pain on percussion and/or visible pocket depth. Radiographic examination showed long and deep pulp chamber and rotated and curved roots with broken apical lamina dura. The tooth was diagnosed with necrotic pulp and asymptomatic apical periodontitis. After making an access to the pulp chamber, two orifices were easily detected while the third one was found by the aid of surgical microscope. The canals were cleaned and shaped using ProTaper Gold file and then obturated with BioCeram Sealer and Gutta-Percha points, using hydraulic bonded obturation technique. Tooth immediately received the final crown. Clinical and radiographical examination after a 3-month follow-up revealed successful peri-apical healing with no symptoms. A literature search was organized to review the past publications about management of mandibular second premolar with taurodontism or anomalies in the root canal system. The search was focused on cases reported in Medline, Scopus, and Google Scholar databases. The conclusion of the seven selected studies and reported cases revealed that proper visualization with advanced microscopes or computer imaging radiographs, negotiation of the root canals, and efficient instrumentation and obturation enhance endodontic success.

Evaluation of the Fracture Resistance Offered by Three Different Intraorifice Barriers on Obturated Teeth: An In-vitro Study

Introduction: The mere placement of a restoration after obturation carries the risk of the presence of voids between them. These voids reduce overall strength and allow for leakage. The placement of Intraorifice Barriers (IOB) between the restoration and the obturated material has been known to have several advantages, including the prevention of microleakage, enhancement of strength, and improvement in Fracture Resistance (FR). Aim: To evaluate if, Smart Dentin Replacement (SDR) flow plus, Resin Modified Glass Ionomer Cement (RMGIC), and Biodentine increase the FR of Endodontically Treated Teeth (ETT) as IOB. Additionally, the study aimed to compare the FR between roots sealed using Endosequence and AH Plus sealers. Materials and Methods: This in-vitro study was carried out in the Department of Conservative Dentistry and Endodontics, Goa Dental College and Hospital, Bambolim, Goa, India over a period of four weeks, from October 2020 to November 2020. The study sample consisted of 160 mandibular premolar roots instrumented using ProTaper gold rotary files. These roots were obturated with Gutta Percha (GP) and divided into two groups based on the sealer used (Group I=Endosequence; Group II=AH Plus). Each group was further divided into four subgroups, including a control group, with each subgroup receiving an IOB. FR was tested using a universal testing machine, and the forces were statistically analysed using Two-way Analysis of Variance (ANOVA), One-way ANOVA, and posthoc Bonferroni tests. Results: SDR offered the greatest FR values of 583.08 N and 612.13 N in groups I and II, respectively. Roots sealed with AH Plus showed greater FR than those sealed with Endosequence. In both groups, the differences between IOB and the control group in terms of FR were found to be highly significant (p&lt;0.001). Conclusion: SDR showed the greatest FR when compared with RMGIC and BD as IOB in ETT. Teeth restored with SDR and sealed with AH Plus offered the greatest FR.

A confocal laser scanning microscopic evaluation of nonthermal atmospheric plasma on the dentinal tubule penetration of bioceramic and epoxy resin-based root canal sealers.

Using confocal laser scanning microscopy (CLSM), the current study assessed the impact of nonthermal atmospheric plasma (NTAP) on the dentinal tubule penetration of bioceramic and epoxy resin-based root canal sealers (CLSM). Forty human mandibular premolar teeth with a single root that had just undergone extraction were chosen and biomechanical preparation of root canals was done with ProTaper Gold rotary Nickel-titanium instruments. Samples were divided into four groups (n = 10). Group 1: Bioceramic sealer (BioRoot RCS); Group 2: Epoxy resin-based sealer (AH Plus) without application of NTAP; Group 3: Bioceramic sealer (BioRoot RCS); and Group 4: Epoxy resin-based sealer (AH Plus) with the application of NTAP for 30 s. In Groups 3 and 4, all of the samples underwent obturation with the appropriate sealers following NTAP application. For determination of the sealer's dentinal tubule penetration values, slices with a thickness of 2 mm were taken from the middle third of sample's root and examined using CLSM. The acquired data were statistically analyzed with one-way analysis of variance and the Post hoc Tukey's test. The cutoff for statistical significance was P < 0.05. In comparison to other groups, the maximum sealer penetration values into dentinal tubules were significantly higher in Group 3 for Bioceramic sealer with NTAP application and Group 4 for Epoxy resin-based sealer with NTAP application. NTAP application increased the dentinal tubule penetration of bioceramic and epoxy resin-based sealers in comparison to groups without NTAP application.

In vitro evaluation of apical leakage of three bioceramic materials using glucose leakage model in a simulated open apex

Background: Recently, new calcium silicate-based materials have been introduced as root-end filling material which offers improved color stability and handling characteristics, while exhibiting physical and chemical properties comparable with mineral trioxide aggregate (MTA). Aim: The purpose of this study was to compare the sealability of 3 calcium silicate-based materials - MTA Plus (Prevest Denpro, India), Biodentine (Septodont, St. Maurdes Fossés, France), and TotalFill BC RRM (FKG, Brasseler, Savannah, USA) in a simulated open apex model. Materials and Methods: Thirty-two recently extracted human maxillary anterior teeth with single, straight root canals were selected and after establishing the working length, canals were prepared by Protaper Gold system up to size F3. The apical end was resected at 3 mm to simulate an open apex. Prepared roots were divided into groups according to the root repair materials – MTA (Prevest Denpro, India), Totalfill Bioceramic Root Repair Material (FKG, Brasseler, Savannah, USA), and Biodentine (Septodont, St. Maurdes Fossés, France). The apical plug of the root filling material was placed in the orthograde direction and a glucose leakage model was used to study the sealability of the materials. Results: All three materials showed more leakage at 14 days than at 7 days, however, there was no statistically significant difference between them. Conclusion: All three bioceramic materials exhibited equal amounts of apical leakage at 7 and 14 days.

Investigation of the thermal and physicochemical behavior of two types of gutta-percha cones for back-filling the root canal.

Gutta-percha (Gp) is an inert thermoplastic polymer used as a filling to replace the dental pulp space, which has been reformulated to improve its three-dimensional sealing properties. Therefore, this study aimed to analyze the physical, chemical and thermal properties of two types of gutta-percha filling. As well as measuring the temperature distribution along the cone at the time of cutting through an in-situ test. Two commercially available brands of gutta-percha point were investigated: Conform Fit TM Gutta-Percha for ProTaper Gold® (PTG) (Dentsply Sirona), and Hygenic Gutta-Percha (Coltene whaledent). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were selected for the thermal characterization of materials, and Fourier Transform Infrared Spectroscopy (FT-IR) for the chemical analysis of Gp cones. Regarding temperature distribution, it was evaluated using a thermographic camera (FLIR ONE® PRO by MicroUSB P/N 435-0011-01) at 0 to 20 s after the cutting process (n=11/group). Both materials have three fusion endotherms associated with the three crystalline phases of Gp, with similar temperatures but enthalpies that differ by 60%, the fusion enthalpy being higher for Conform Fit. In the chemical characterization, elements such as Zn, C, O, Ba, S and Si were found in both materials but in different proportions. Regarding the content of fillers, the Conform Fit presented around 30% of Gp polymer and 25% for the Hygenic. The morphological characterization shows a microtexturized coating in the form of bars on a micrometric scale for the Conform Fit, which could favor a better three-dimensional seal. In addition to that, in heat transfer studies they showed greater temperature control. The characterization of the materials allowed us to see the variation in terms of their composition and configuration to the Gp cones of two commercial brands. These variations directly modify the thermal behavior of the material. Key words:Gutta-percha, Conform Fit, Infrared thermography, Differential Scanning Calorimetry, Infrared Spectroscopy.

Cyclic Fatigue Resistance of Hyflex EDM and ProTaper Gold Files at Different Locations of Canal Curvature

Aim: Study's purpose was to evaluate and compare the fatigue resistance of ProTaper Gold and Hyflex EDM files at five different locations of canal curvature.&#x0D; Methods: Two types of NiTi files; ProTaper Gold and Hyflex EDM (n=80) with similar sizes (25/0.08) were used as two main groups (n=40), each group subdivided into five subgroups (n=8) according to distance from the orifice to curvature which are; 11, 10, 8, 6 and 5 mm. Five stainless steel canals were fabricated. Each canal had 16 mm length, 1.5 mm width and single curvature with 3-mm radius and 60° angle. Fractured samples were examined under a scanning electron microscope. Independent t-test, One-way ANOVA and Posthoc tests assessed the data statistically.&#x0D; Results: Number of cycles to fatigue for the Hyflex EDM file was significantly higher than the ProTaper Gold file at all curvature levels (p≤0.05). The files demonstrated significantly higher number of cycles to fatigue in canals of (10 and 11) mm when compared to the canals of (5, 6, and 8) mm (p≤0.05).&#x0D; Conclusion: Hyflex EDM files showed higher fatigue resistance than ProTaper Gold files. The canal curvature position had a substantial impact on the resistance of the NiTi file, with short life coronally.

Characterization of the file-specific heat-treated ProTaper Ultimate rotary system.

To compare design, metallurgy and mechanical performance of the ProTaper (PT) Ultimate system with instruments of similar dimensions from the ProGlider, PT Gold and PT Universal systems. New PT Ultimate instruments (n=248) were compared with instruments of similar dimensions from ProGlider (n=31), PT Gold (n=155) and PT Universal (n=155) systems regarding their number of spirals, helical angle, blade symmetry, tip geometry, surface finishing, nickel/titanium ratio, phase transformation temperatures and mechanical performance. One-way anova and nonparametric Mood's median tests were used for statistical comparison (α=5%). All instruments had symmetrical blades without radial lands or flat sides, similar surface finishing and an almost equiatomic nickel/titanium ratio, whilst the number of spirals, helical angles and the tip geometry were different. PT Ultimate instruments showed 3 distinct heat treatments that matched with the colour of their metal wire. Slider and ProGlider instruments had similar R-phase start (Rs) and R-phase finish (Rf) temperatures. SX, F1, F2, F3 and Shaper instruments showed equivalent heat treatments (Rs ~45.6°C and Rf ~28.3°C) that were similar to their PT Gold counterparts (Rs ~47.9°C and Rf ~28.2°C), but completely distinct to the PT Universal ones (Rs ~16.2°C and Rf ~-18.2°C). Amongst the PT Ultimate instruments, the lowest maximum torques were observed in the SX (0.44 N cm), Slider (0.45 N cm) and Shaper (0.60 N cm) instruments, whilst the highest was noted in the FXL (4.90 N cm). PT Ultimate Slider and ProGlider had similar torsional (~0.40 N cm) and bending loads (~145.0 gf) (p=1.000), whilst the other PT Ultimate instruments showed statistically significantly lower maximum torque, higher angle of rotation and lower bending load (higher flexibility) than their counterparts of the PT Universal and PT Gold systems. The PT Ultimate system comprises instruments with 3 distinct heat treatments that showed similar phase transformation temperatures to their heat-treated analogues. PT Ultimate instruments presented lower torsional strength and superior flexibility than their counterparts, whilst maximum torque, angle of rotation and bending loads progressively increased with their sizes.

Effect of different axial speed patterns on cyclic fatigue resistance of rotary nickel-titanium instruments

BackgroundTo evaluate the effect of pecking motions with faster upward speed on the dynamic cyclic fatigue resistance of nickel-titanium rotary instruments with different metallurgy.MethodsForty each of ProTaper Universal F3 (PTU) and ProTaper Gold F3 (PTG) instruments (size #30/.09) were equally divided into four groups. The test was performed using an 18-mm-long stainless steel artificial canal with a 5-mm radius of curvature, a 45° canal curvature and a 2-mm canal diameter. A downward speed of 100 mm/min was employed, while the upward speed was set at 100, 150, 200 or 300 mm/min. Time to failure (Tf), number of cycles to failure (Nf) and number of pecking motions to failure (Np) were recorded. Statistical analysis was performed using Kruskal Wallis and Mann–Whitney U tests for Tf, Nf, and Np (α = 0.05).ResultsThe 100/300 mm/min group showed significantly higher Np values than the 100/100 mm/min group (p < 0.05), whereas there were no significant differences in Tf and Nf among the tested speed groups (p < 0.05) in either PTU or PTG. PTG exhibited significantly higher Tf, Nf, and Np than PTU (p < 0.05).ConclusionsUnder the tested conditions, the fastest upward speed group showed significantly higher cyclic fatigue resistance, as demonstrated by larger Np, than the same speed group. PTG had significantly higher cyclic fatigue resistance than PTU in all groups.

To Evaluate the Accuracy Between Two Different Electronic Apex Locators to Detect the Root Canal Perforation During Retreatment - An Ex-Vivo Study

Objectives: To evaluate the accuracy between two different electronic apex locators in detecting the root canal perforation in the middle and apical portion during retreatment. Methods: Sixty freshly extracted mandibular premolars were taken in to this study, which were divided into three groups of twenty each. Group I: Control Group, Group II: Positive control without perforation, Group III: Negative control with perforation. In all the groups, access cavity preparation was done followed by cleaning and shaping using X smart Endomotor and Protaper Gold file system (Dentsply Maillefer, Switzerland). The specimens were prepared such that perforation was made in group III on the mesial side of the root at middle portion approximately 5mm from the apex after determining working length by direct visualization and stored for the database. All the specimens were obturated by using AH plus sealer and F3 Protaper gold gutta percha points and later stored in incubator at temperature of 37°C for 7days. After 7 days, gutta percha was removed from group III samples using gutta percha solvent (Xylene), Neo-Endo retreatment files. These teeth were mounted on Protrain Endodontic training kit (Simit Dental, Italy) and perforation were detected using apex locators Dentaport Root ZX (J,Morita) and Propex Pixi (Dentsply Maillefer, Switzerland). The apical perforation were made at a distance 2mm from apex after the middle perforation were restored by using Type II GIC by keeping the 35 K file inside the canal and apical perforations were detected and the reading were recorded and stored for the database. Statistical Analysis: The data obtained were analyzed by using descriptive statistics, ANOVA (Analysis of Variance), Paired t test through SPSS for window (version 22.0). Findings: In case of middle third perforation of the root canal Dentaport Root ZX showed accuracy of 87.37% and Propexpixi 82.89%. In apical perforations the accuracies of Root ZX and Propex Pixi are 89.28% and 79.76% respectively. In the both the perforations, there was a statistically significant difference (P < 0.05). In both the perforations, Dentaport Root ZX showed more accuracy in detecting the perforation when compared with Propex Pixi apex locator. Novelty : This study provides a novel approach as it compares the accuracy between the Dentaport Root Zx and Propex Pixi in detection of middle and apical perforation during retreatment in Ex Vivo study. Keywords: Dentaport root ZX; Electronic apex locator (EAL); Propex pixi; Protrain endodontic training kit; Root canal perforation

Effect of Periodic Changes in Rotation Speed on Torsional Stress and Screw-in Force by Alternative Rotation Technique

IntroductionThis study evaluated the effect of periodic changes in rotation speed on torsional stress and screw-in force using the dedicated alternative rotation technique (ART) motion of the EQ-M (Metabiomed, Cheongju, Korea) endodontic motor. MethodsTwo ART modes of the EQ-M motor in 2 alternative techniques (ART30 and ART50) and continuous rotation were compared using ProTaper Next X2 (Dentsply Sirona, Charlotte, NC) files and simulated resin blocks (n = 12 per group). ART30 and ART50 were operated by continuous rotation of 350 rpm for 360° and then rotated at 30% increased speed from the base speed for 180° and at 50% increased speed for 180°, respectively. Before the test, the simulated resin blocks were pre-enlarged using ProTaper Gold S1 and S2 (Dentsply Sirona) and fixed on a metal stage connected to the force- and torque-measuring unit. During shaping the simulated canal in an automatic up-and-down manner, the parameters of maximum torque, sum of torque, maximum screw-in force, and maximum apical force were measured. The data were statistically analyzed using 1-way analysis of variance and the Tukey post hoc comparison test at the 95% significance level. ResultsThe ART30 and ART50 groups showed a lower maximum torque, sum of torques, screw-in force, and apical drive force than the continuous rotation group. There was no significant difference between the ART30 and ART50 groups (P > .05). When the screw-in force increased suddenly, the torque correspondently increased. ConclusionsUnder the limitations of this study, the ART mode could reduce the torsional stress and apical forces of the screw-in during instrumentation in comparison with continuous rotation.

Effect of Type of Motion on Torque Generated Intra-canally (in Vitro Study)

Objective: To measure cumulative torque values generated during different types of motions during instrumentation by rotary files. Method: Forty extracted human premolar teeth with single canal have been utilised, instrumentation was performed with a single-file procedure with tip end no. 25 and taperness of 6% by two groups of files; Protaper Gold and Wave One Gold. Each group was subdivided into two subgroups; Group A (10 in no.) set at 2.5 N.cm2. Group B (10 in no.) set at 1 N.cm2 using an endodontic motor. A software has been used for precise torque measurements of range of 0.05 N.cm2 for every 30 seconds. Results: The t test showed a highly significant difference between groups 1A and 2A (p≤.01). Cumulative torque also showed non-significant differences by the groups 1B and 2B, (p≥.05) (Table 2). Conclusion: At high torque setting, the preparation mode was affected by cumulative torque values whereas the same comparison was neutral at low torque control motor

Evaluation and comparison of apical bacterial extrusion after instrumentation of the root canals using various endodontic file systems: An in vitro study

Aim: The purpose of this research is to compare the amounts of bacteria that are extruded from their apical surfaces during the instrumentation of root canals utilising the K3XF, Protaper Gold, Edge taper Platinum, and Hyflex CM Rotary systems.Materials and methods: Sixty caries free single rooted human maxillary incisor teeth were divided in six groups of ten teeth each. Teeth in each group were instrumented until the working length with the respective rotary file system. The access cavity was made, and the pulp and debris were removed from the canals. On the device for gathering microorganisms, the teeth were mounted. The Fusobacterium Nucleatum (ATCC 25586) was used to infect the root canals, which were then dried at 37 °C for 24 hours. Group I (Control group), no instrumentation was done. Group II used hand K-files, Group III used Protaper gold, Group IV used K3XF, Group V used Edge taper platinum, and Group VI used Hyflex CM rotary file systems. In. The sample was then collected, cultured in Mueller-Hinton agar for 24 hours, and the number of colony-forming units was counted.Statistical analysis: The Kruskal-Wallis nonparametric test and Mann-Whitney U test were applied to determine if significant differences existed among the groups ( P&lt; 0.05)Results: Comparing hand K-files to the other four rotary systems, the K3XF file system extruded the fewer number of bacteria.Conclusion: Within the limitations of this study, it can be concluded that all instruments tested produced bacteria from intracanal spaces apically. However, compared to the manual method, engine-driven nickel-titanium devices extruded fewer microorganisms. Comparatively, the K3XF rotary file system extruded less microorganisms than other rotary file systems.