Mesiobuccal Canals Of Maxillary Molars Research Articles

Location of the Second Mesiobuccal Canal of Maxillary Molars in a Brazilian Subpopulation: Analyzing Using Cone-beam Computed Tomography.

This study aimed to evaluate the spatial location of the second mesiobuccal canal (MB2) of maxillary molars (MMs), using cone-beam computed tomography (CBCT), in a Brazilian subpopulation. The CBCT examination of 250 patients performed on the Eagle 3D device was analyzed, totaling 787 MMs. Using the Radiant Dicom Viewer software, measurements were made of the distances, in millimeters (mm), between the first mesiobuccal canal (MB1), MB2, and palatal (P) canal inputs, from the axial sections. The Image J software evaluated the angle formed by the lines. The data obtained were analyzed statistically by Fisher's exact and Chi-square tests with a significance of 5%. The prevalence of MB2 canals observed was 76.44 and 41.73% in the first and second molars (1MMs and 2MMs), respectively (p < 0.05). The average of the distances and angles performed, for the location of the MB2 canals of the analyzed teeth, were MB1-P = 5.83 mm, MB1-MB2 = 2.31 mm, and MB2 for the intersection of the connecting distance from MB2-T = 0.90 mm. The average angle formed between the MB1-P and MB1-MB2 distances was 25.89° and 19.68° for the 1MMs and 2MMs, respectively. It was also observed that 91.4 and 75.4% of the maxillary 1MMs and 2MMs, respectively, presented the MB2 canals mesially located at the line connecting the MB1-P canals (p < 0.0001). The MB2 canals were located mesially to the MB1 canal with an average distance of 2 mm between the canals. The anatomical knowledge of the spatial location of the MB2 canal in different ethnicities is important for the planning and execution of endodontic treatment.

Negotiability of mesiobuccal canals in maxillary first molars using different path file systems

Background: In endodontics, glide path creation has been extensively considered a mandatory clinical step to improve the safety and efficiency of rotary nickel–titanium instruments. The high anatomic variations in the mesiobuccal (MB) root of the maxillary molars are observed in the form of canal configuration, number, and position.The aim of this study was to evaluate the negotiability of MB canals in maxillary molars using different pathfiling systems (ProGlider, R-pilot, HyFlex electrical discharge machining [EDM], WaveOne Gold Glider, and C-Pilot).Materials and Methods: This in vitro study included 125 maxillary first molars with closed apex. Before preparation, all teeth were scanned by periapical radiograph for review of the presence of second MB (MB2) canals, without any resorption or calcification, and moderate curve of MB root canal. Subsequently, the access cavity was prepared with a Diamond Fissure Bur. Then, the samples were divided into five groups (ProGlider, R-pilot, HyFlex EDM, WaveOne Gold Glider, and C-Pilot). Certain relevant indices were recorded for analysis, such as the negotiability of the glide path file in the MB canals, file fracture rate, and negotiation speed. The level of significance P value was set at 0.05.Results: In this study, HyFlex EDM was the only path file that could not reach the full working length (WL) in some cases. The highest frequency of file fracture in the MB2 was observed with HyFlex EDM (24%); nevertheless, R-Pilot presented an intermediate fracture rate (16%), and both ProGlider and WaveOne Gold Glider were the safest files (4%) in this regard. However, there were no significant differences between the groups (P = 0.065). The lowest and the highest average time of reaching full WL was observed with WaveOne Gold Glider and HyFlex EDM; nonetheless, there was no significant difference between the four rotary groups. The average number of pecks in HyFlex EDM was significantly higher in comparison to those reported for WaveOne Gold Glider and ProGlider.Conclusion: Path files used for glide path preparation in the MB2 canals of maxillary molars should be flexible with low taper. The use of HyFlex EDM in the MB2 canals is not recommended due to its high taper.

Location angle of second mesio-buccal canal in maxillary molars of an Indian population: an in vivo retrospective CBCT evaluation and proposal of a new classification.

BackgroundThe current investigation was designed for predicting the location angle of second mesio-buccal root canal in permanent maxillary (first and second) molars with the aid of proposed measuring points and line using cone beam computed tomography in an Indian population.MethodsThree-hundred and twenty-four scans of permanent maxillary (first (n = 162) and second (n = 162)) molars with mesio-buccal 2 root canals and unassociated to the current evaluation were acquired. The maxillary molars were viewed with CSI imaging software. The images were captured and were further assessed using 3D Slicer. The assessment included of measuring the distance between the main mesio-buccal and mesio-buccal 2 canal and the angle at which the MB2 it is located utilizing proposed lines joining the disto-buccal and palatal canals. The data was tabulated for the incidence of various angles where the MB2 is located and MB-MB2 distance was determined. The angles denoted were either positive; I (0.1° to 1.9°), II (2° to 4°), III (>4°) or negative I (−0.1° to −1.9°), II (−2° to −4°), III (>−4°). On the data tabulated a new Banga Vhorkate and Pawar’s (BVP’s) angular classification for maxillary molars was proposed.ResultsThe existence of positive angle III was found in 41.35% of maxillary first molars (36 right and 31 left of 162), whereas positive angle II appeared in 41.98% of maxillary second molars (32 right and 36 left of 162). The MB1–MB2 in maxillary 1st molar is seen to be 3.12–3.31 mm and this distance in maxillary 2nd molar is 2.8–3.1 mm. The disto-buccal to palatal canal orifice mean distance was 5.06–5.22 mm in maxillary first molars and 4.9–5.8 mm in maxillary second molars.ConclusionAccurate diagnosis of the location of second mesio-buccal canal increases the success rate of endodontic treatment and a better prognosis. The new proposed classification may be considerably helpful in the urge to locate the mesio-buccal 2 canal.

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.

The Article Abstract is not available.

XP Endo Finisher-R and PUI as supplementary methods to remove root filling materials from curved canals.

This study assessed the ability of XP-endo Finisher R (FKG, La Chaux-de-Fonds, Switzerland) to remove filling remnants from curved mesiobuccal canals of maxillary molars, using the passive ultrasonic irrigation (PUI) technique as a comparison. Twenty-four curved main mesiobuccal canals (MB1) of maxillary molars were instrumented with Wave One (#25/07) and filled with gutta-percha points and AH Plus Sealer. Samples were then re-treated with a standardized protocol with Wave One (#35/06) as the master apical file. Micro-CT scans measured baseline volume of remaining filling material (in mm3). Samples were divided into two groups (n = 12) according to the supplementary cleaning approach: (PUI) or XP-endo Finisher R. Statistics compared baseline and final volume of filling material (within-group); and the percentage of filling material reduction (between-group). Mean baseline volumes, final volumes, and percentages of reduction (%) of filling material for XP-endo Finisher R and PUI were respectively: 0.060 mm3, 0.042 mm3, and 31.28%; and 0.064 mm3, 0.054 mm3, and 16.57%. Both tested protocols reduced the amount of filling material (p < 0.05). XP-endo Finisher R had higher percentage of reduction as compared to PUI (p < 0.05). XP-endo Finisher R and PUI used as supplementary cleaning protocols during re-treatment improved the removal of root filling material in curved canals; but XP-endo Finisher R was approximately twice more efficient. The complete filling material removal during re-treatment procedures is still a challenge. Supplementary cleaning protocols may help to remove the remaining material after the complete mechanical preparation of curved canals. XP-endo Finisher R was approximately twice more efficient than PUI.

Metallurgical characterisation and torsional resistance of blue thermomechanically treated nickel titanium instruments after simulated exvivo retreatment procedure.

To compare used and unused Reciproc Blue and Reciproc after retreatment, the instruments were used in the mesiobuccal canals of maxillary molars with curvature. The torsional resistances were tested and then unused instruments were subjected to XRD, DSC and microhardness tests. Student's t, ANOVA and Tukey's tests were performed (α-level 0.05). The torsional strength of used Reciproc Blue was not significantly different than unused ones (P > .05), while torsional strength of Reciproc decreased significantly (P < .05). DSC and XRD indicated that Reciproc Blue exhibited prominent transformation peaks corresponding austenite to R-phase. Microhardness of Reciproc was significantly higher (P < .05). A second reuse of Reciproc Blue for retreatment could be considered safe in terms of torsional strength. Blue treatment also decreased surface microhardness of the instrument and changed phase composition by increasing the R-phase.

In vitro study to compare the accuracy of four diagnostic methods for locating the second mesiobuccal canal in maxillary molars

The aim of this in vitro study is to compare the efficacy of three diagnostic methods, Direct visual method, Magnifying loupes and Dental operating microscope in recognising all the canals of the root canal system in maxillary first molars using CBCT and reference standard method. A total of 65 maxillary first molars were selected for this study. Teeth selected were evaluated by Periapical radiographs and CBCT. Access cavities of selected extracted human maxillary first molars were prepared, and the floor of the pulp chamber was then explored to locate the MB2 canal in five stages: Stage I (Direct Visual Method), Stage II (under ×3.5 Magnifying Loupes with light-emitting diode [LED] light), Stage III (Under Dental Operating Microscope), and Stage IV (Cross-sectioning was done below CEJ and the sections were evaluated using stereomicroscope at 10x magnification). The descriptive statistics were tabulated using Chi square test to compare the efficacy between the diagnostic methods. Senstivity, specificity, Positive /Negative predictive values were calculated for each method. The results obtained in this study showed that CBCT was most accurate with the dimensional accuracy of 96% followed by Dental operating microscope which performed better (with the diagnostic accuracy of 76%) than the magnifying loupes (with the diagnostic accuracy of 64%) direct visual method (with the diagnostic accuracy 60%). The dental operating microscope was most effective in the detection of MB2 canals followed by magnifying loupes and direct visual method. Additionally, CBCT could be used as a supplementary diagnostic tool in cases in which canals are not found using the methods available in the dental office.

A comparative evaluation of canal transportation, centering ability, and volumetric increase in the curved canals using thermally treated three nickel-titanium rotary files: A cone-beam computed tomography study

Aims: The aim of this study was to evaluate and compare canal transportation (CT), centering ability (CA), and volumetric changes in the curved canals prepared using Hyflex Electrical Discharge Machining (HEDM), ProTaper Gold (PG), and NeoEndo Flex rotary file systems through cone-beam computed tomography (CBCT).Materials and Method: Sixty mesiobuccal canals of maxillary molars were selected. Pre- and postinstrumentation CBCT scans were taken in the same position. CT and CA were calculated at 1 mm, 4 mm, and 7 mm from the apex; change in volume for the whole canal was measured and analyzed statistically.Results: The results showed that mean CT of HEDM and NeoEndo was less than PG at all levels, with significant differences at 4 mm and 7 mm. Regarding CA, no significant differences were found among the file systems. PG showed maximum volumetric increase with no statistically significant differences between the groups.Conclusion: All the experimental file systems respected the canal anatomy, although in the middle third, PG showed significantly more CT than HEDM and NeoEndo, whereas in the coronal third, PG showed significantly greater CT than NeoEndo. Regarding CA, no significant differences were found among the file systems. PG showed maximum volume of dentin removal.

Shaping ability of ProTaper Gold, One Curve, and Self-Adjusting File systems in severely curved canals: A cone-beam computed tomography study.

Aim:The aim of the study was to evaluate and compare canal transportation (CT), centering ability (CA), and volumetric changes in severely curved canals prepared using ProTaper Gold (PTG), One Curve (OC), and Self-Adjusting File (SAF) systems via cone-beam computed tomography (CBCT).Materials and Methods:Sixty mesiobuccal canals of maxillary molars were selected. Pre- and postinstrumentation CBCT scans were taken in the same position. CT and CA were calculated at 1 mm, 4 mm, and 7 mm from the apex; change in volume for whole canal was measured and analyzed statistically.Results:SAF showed the least mean CT at all the levels with no statistically significant differences at 1 mm and 4 mm when compared to other groups while statistically significant differences were observed at 7 mm with PTG and OC. Regarding CA, SAF better maintained canal centricity than PTG and OC at all the levels assessed, though the differences were not statistically significant except at 7 mm where statistically significant difference was observed between SAF and OC. SAF removed less volume of dentin followed by PTG and the highest removal was shown by OC.Conclusion:SAF showed promising behavior with the least CT, most centered preparation, and minimal dentin removal.

A review on significance of second mesio-buccal canal in maxillary molars

Maxillary molars present a wide range of root canal configurations ranging from three canals to seven canals. Very few authors have found maxillary molars with seven canals but the incidence of the fourth canal is considered very common now. Therefore, second mesiobuccal canal is no longer considered an accessory canal. This review article describes the anatomy of the maxillary first molar, prevalence, and incidence of MB2 canals, ways to negotiate the hidden MB2, and its significance.

Influence of endodontic cavity access on curved root canal preparation with ProDesign Logic rotary instruments.

This study evaluates whether endodontic cavity access into molars influences the chemomechanical preparation of curved root canals. Twenty mesiobuccal canals of maxillary molars were randomly divided into two experimental groups (n = 10), according to the type of endodontic access analyzed (conventional and minimally invasive). The preparations were made by a single operator, and the canals, after access, were prepared with Logic system (0.25, 0.04 taper) along the working length. Samples were scanned before and after canal preparation (SMX-90CT Plus (Shimadzu® microtomograph operated with 70 kV, 100 uA, FOV (XY) 13.3 mm, FOV (Z) 7.0 mm, and voxel size 0.013 mm/Pix)) to match canal volumes. Images were analyzed to evaluate surface areas, transport, and centralization at 3 mm from the canal entrance and 3 mm from the apex (OnDemand3DTM Dental software). Student's t test with a significance level of 5% was used for the statistical analysis. Regardless of the position of the analyzed canals, there was no difference in the prepared area regarding the transport and centralization of the endodontic instrument between the two types of cavity accesses performed. The conventional and minimally invasive access did not influence the action of the 0.25 and 0.04 taper instrument during the curved root canal preparation. The type of endodontic access did not influence the action of the rotary instrument during the curved root canal preparation.

Evaluation of the Amount of Root Canal Dentin Removed and Apical Transportation Occurrence after Instrumentation with ProTaper Next, OneShape, and EdgeFile Rotary Systems

IntroductionThe aim of this study was to evaluate the amount of root canal dentin removed and apical transportation occurrence after instrumentation of mesiobuccal canals of maxillary molars with ProTaper Next (PTN [Dentsply Maillefer, Ballaigues, Switzerland]), OneShape (OS [MicroMega, Besançon, France]), and EdgeFile (EF [Edge Endo, Albuquerque, NM]) rotary systems. MethodsTwenty-seven mesiobuccal canals of maxillary molars were used. Canals were randomly divided into 3 groups for canal preparation: PTN, EF X3, or OS (n = 9 for each group). Micro–computed tomographic imaging was used to measure apical transportation (mm) and the volume of dentin removed (mm3). The amount of dentin removed was measured for the coronal portion and for the whole canal length. Superposition of pre- and postoperative cross-sectional apical slices were used to measure apical transportation at 1 mm from the apex; the differences were evaluated using the Kruskal-Wallis test and Wilcoxon analysis. The Spearman correlation coefficient was used to display the relationship between variables for each group. The significance level was set at P < .05. ResultsThe percentages of the amount of dentin removed on the coronal portion and the amount removed for the whole canal length were statistically similar between groups (P > .05). The average amount of apical transportation for the PTN, OS, and EF X3 were 0.197, 0.263, and 0.218 mm, respectively. Statistically, there were no significant differences between the 3 rotary instruments for apical transportation. ConclusionsThe amount of dentin removed for the coronal third portion and the whole canal length was similar for the PTN, OS, and EF X3 rotary instruments. Although there were differences in the sizes of apical enlargement, no apical transportation was observed in any of the instrumentation systems.

Evaluation of canal transportation and centering ability in mesiobuccal canals of maxillary molars using two Ni-Ti file systems: An ex-vivo micro-computed tomographic study

Aim: This study aims to evaluate and compare the canal transportation and centering ability of two nickel–titanium file systems, ProTaper Next and WaveOne Gold, in comparison with ProTaper Universal in mesiobuccal canals of maxillary molars using micro-computed tomography. Materials and Methods: Seventy-five permanent maxillary first and second molars having mesiobuccal canals with curvatures between 20° and 30° were selected and subjected to pre-operative micro-computed tomographic scans. They were then divided into three groups (n = 25) based on the file system to be tested: Group 1-ProTaper universal (control), Group 2: ProTaper Next, and Group 3-WaveOne Gold. Access cavities were prepared, following which each specimen was instrumented using the specific file system. Post-instrumentation micro-computed tomographic scans were then carried out for each specimen. Pre- and post-instrumentation measurements of mesiobuccal canals were performed using the ImageJ 1.8.0 software. Canal transportation and centering ratio were calculated at three cross-section levels that corresponded to 3-mm, 6-mm, and 9-mm distance from the apical end of the root. The data obtained were then subjected to statistical analysis using ANOVA and Tukey's post-hoc tests. Results: It was seen that WaveOne Gold caused the least overall canal transportation and exhibited the highest centering ability, followed by ProTaper Next and ProTaper Universal, though the difference was not significant. Furthermore, there was no significant difference between the canal transportation and centering ability of ProTaper Universal, ProTaper Next, and WaveOne Gold at all three levels. Conclusion: None of the systems evaluated exhibited perfect centering ability and zero canal transportation. All file systems caused root canal transportation and minor changes in the root canal anatomy.

Impact of dental operating microscope, selective dentin removal and cone beam computed tomography on detection of second mesiobuccal canal in maxillary molars: A clinical study.

Maxillary molars may frequently require root canal therapy and can have complex anatomy. It is important to locate and treat the second mesiobuccal canal to significantly improve prognosis. The purpose of this study was to evaluate direct vision, dental operating microscope (DOM), selective dentin removal under DOM, and cone beam computed tomography (CBCT) in clinical detection of second mesiobuccal root canal (MB2) in maxillary molars. A total of 122 maxillary first and second molars indicated for root canal treatment were included in our study. Following access cavity preparation, the presence of MB2 canal orifice was assessed in four stages. Stage I: with direct vision. Stage II: under DOM, Stage III: after selective dentin removal under DOM and Stage IV: teeth in which MB2 canal was not identified by Stage III were further investigated with CBCT. The number of canals identified during each stage was analyzed statistically. Clinical detection of MB2 canal in our study was 90%, with 93% in maxillary first molar and 86% in maxillary second molar. 64% MB2 canals were located at Stage I (direct vision) which improved to 84% at Stage II (under DOM) and 90% at Stage III (selective dentin removal under DOM). CBCT investigation (Stage IV) further improved the identification of MB2 canal leading to overall prevalence of 93%. The results of our study demonstrated that MB2 canal can be clinically detected in up to 90% of maxillary molars by the use of DOM and selective dentin removal. CBCT investigation is indicated when MB2 canals are not clinically detected.

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.

Negotiation, Centering Ability and Transportation of Three Glide Path Files in Second Mesiobuccal Canals of Maxillary Molars: A CBCT Assessment.

The aim of this study was to compare negotiation, centering ability and transportation of three path finder rotary instruments (ProGlider, ScoutRace and M3 Pro-Gold Path File) to create glide path in second mesiobuccal (MB2) canals of maxillary molars with cone-beam computed tomography (CBCT). In this in vitro study, 66 maxillary molars with separate second MB2 canals were selected with the following criteria: having 18-21 mm root length, without any resorption or calcification in radiography, without previous treatment and 20-40º curve according to Schneider's method. Then MB2 canals were randomly divided into three groups (n=22). CBCT scan before and after root canal negotiation was taken. A #10 K-file for determination of working length was inserted into all canals. In group1; ProGlider file, group2; ScoutRace file and in group 3; M3 Pro-Gold Path file was implemented. The calculated data from CBCT based on reaching full working length (RFWL) or not (NRFWL) were analyzed using the Pearson Chi-square test. Centering ability was calculated by Fisher's exact test and amount of transportation was determined with the Pearson Chi-square test in SPSS software. ProGlider file had the least RFWL and ScoutRace was the best, but the results were not statistically significant (P>0.05). Regarding the centering ability and transportation, all 3 groups showed no significant differences (P>0.05), except at level of 2 mm from the apex in buccopalatal direction for ProGlider and ScoutRace files (P<0.05). In spite of insignificantly different results, ScoutRace file was better than other groups in negotiating and centering ability in mesiodistal direction of the MB2 canal in maxillary molars. Also, ProGlider file was significantly better than ScoutRace regarding transportation at level of 2 mm from apex in buccopalatal direction.

Canal Transportation and Centering after Using PathFile and R-Pilot in Mesiobuccal Canals of Maxillary Molars Using Cone-Beam Computed Tomography.

This study aimed to compare the changes in root canal anatomy following the use of PathFile and R-Pilot using cone-beam computed tomography (CBCT). In this in vitro, experimental study, 60 extracted maxillary first and second molars with 20 to 40° mesiobuccal root curvature, minimum of 19 mm of root length, no calcified root canals and no history of previous treatment were divided into two groups (n=30). CBCT scans were taken before and after the treatment, and sections at 1, 2 and 3 mm from the apex were compared. Pairwise comparisons were carried out using the Mann Whitney-U test. The centering ratio data were analyzed using the Chi-square test and Fisher's exact test. All statistical analyses were carried out using Sigma Stat 4 software. The difference between PathFile and R-Pilot in canal transportation in mesiodistal direction was significant at 1 and 2 mm from the apex (P<0.01). The R-Pilot file was significantly superior to PathFile in centering ability in mesiodistal direction at 1 mm from the apex (P<0.05). Canal transportation direction was towards the mesiolingual and distobuccal in R-Pilot and PathFile groups, respectively. Within the limitations of this study, the results showed that R-Pilot with reciprocal movement is a safe and easy to use instrument for creating a glide path.

Comparison of Canal Transportation and Centric Ability of Two Nickel-Titanium Rotary Systems Using Cone Beam Computed Tomography: An In Vitro Study

Abstract Aim The aim of this study was to compare the canal transportation and canal centric ability of One Shape (Micro Mega, Besançon, France) and Mani Silk (Mani Utsunomiya, Tochigi, Japan) nickel-titanium (NiTi) rotary files in curved canals with the help of cone beam computed tomography (CBCT). Materials and Methods Total 40 mesiobuccal canals of maxillary molars with an angle of curvature ranging between 25 and 45 degrees were divided according to the instrument used in canal preparation into two groups 20 samples each: One Shape (group 1) and Mani Silk (group 2). Pre- and post-instrumentation scans were performed using CBCT (Carestream CS 9300 scanner) to evaluate the transportation and centric ability at apical, middle, and coronal levels using unpaired Student's t-test. Results Mani Silk file showed significantly less canal transportation and better canal centric ability compared to One Shape system. Conclusion Mani Silk file maintained original canal curvature better than One Shape NiTi rotary file.

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.

Efficacy of a thermally treated single file compared with rotary systems in endodontic retreatment of curved canals: a micro-CT study.

This study aimed to compare WaveOne Gold with ProTaper and RaCe systems regarding remaining filling material, apical transportation (AT), and working time (WT) after (i) filling removal and (ii) shaping of curved canals. Thirty mesiobuccal canals of maxillary molars were prepared and filled. After 30days, they were randomly assigned into three groups (n = 10), according to the instruments used for filling removal and shaping, respectively: WOG-WaveOne Gold Primary and Medium; PTG-ProTaper Retreatment and ProTaper Next; RCG-D-RaCe and RaCe. Micro-CT analysis assessed the residual filling material and AT. WT was recorded. Data were statistically analyzed (α = .05). There was no significant difference between groups in the amount of filling material at any evaluated moment (P > .05). All groups presented low AT values. The WT was similar in all groups in filling removal (P > .05), and in shaping step WOG was faster than PTG and RCG (P < .05). Neither system could completely remove the filling material. The instruments evaluated were safe and the reciprocating system was faster than the rotary systems in shaping the canals. This study provided consistent information on filling material removal capacity of WaveOne Gold. Considering that all tested systems were safe, WaveOne Gold may be an alternative with cost-effectiveness and shorter learning curve for endodontic retreatment.