Post-instrumentation Cone-beam Computed Tomography Research Articles

Compare the Centering Ability, Canal Transportation and Root Canal Area Increase of XP Endoshaper, Hyflex CM and K3 XF File System by using Cone Beam: An Original Research

ABSTRACT Objective: Using cone beam computed tomography (CBCT), this study compared three rotary file systems—XP Endoshaper, Hyflex CM, and K3 XF—for centering, canal transportation, and root canal area growth. Materials and Methods: The rotating file system randomly separated 60 removed human mandibular molars into three groups (n = 20). Manufacturer-recommended root canal instrumentation was done. Specialized software examined pre- and post-instrumentation CBCT scans. Centering ability was measured by canal transportation and root canal area expansion at different levels from the apex. Results: The Hyflex CM file system had the best centering and the least canal transit at all levels (P < 0.05). XP Endoshaper increased the root canal area the most (P < 0.05). The K3 XF file system had average centering and canal transfer results. Conclusion: The Hyflex CM system centered well, whereas the XP Endoshaper system increased the root canal area the most. The clinical context and therapeutic goals should determine the rotating file system.

Assessment of Apical Pressures in Single and Joining Canals - An Ex Vivo Study Based on Computational Fluid Dynamic Analysis.

Computational fluid dynamic analysis (CFD) is claimed to be a reliable tool for analysing the fluid flow and the generated apical pressures in the simulated root canal. The current study aimed to analyse the apical pressures in extracted teeth with single and joining canals. Forty-six freshly extracted teeth were collected for the present study. The power was set at 95%, with an effect size of 0.55 (1-β=95%, α=0.05). Once the root canal anatomy was confirmed with cone-beam computed tomography (CBCT), they were divided into two groups: group I: mandibular second premolars with Vertucci type-I (n=23), and group II: maxillary second premolars with Vertucci type-II (n=23). The instrumentation of the specimens was carried out to a 0.04-taper using rotary instruments. A post-instrumentation CBCT was obtained, and computer-aided design models were obtained. The CFD simulations were then con- ducted with simulated 30-gauge side vented needles at 25, 50, and 75% short of the working length (WL). Group I recorded significantly (p<0.05) higher apical pressures at needle positions 25% short of the WL. However, no significant differences were elicited in the groups at other needle positions. Single canal specimens recorded higher apical pressures at needle positions 25% short of the WL. However, no differences were elicited between single and joining canals at higher needle positions.

Evaluation of Canal-centering Ability and Apical Transportation of Hyflex-EDM, OneShape, WaveOne Gold, and Reciproc Files: An Ex Vivo Study.

To evaluate and compare canal-centering ability (CCA), canal transportation (CT), and dentinal crack formation by using Hyflex-electrical discharge machining (EDM), OneShape, WaveOne Gold, and Reciproc single file system in the mesiobuccal root of maxillary first molar at coronal, middle, and apical third using cone-beam computed tomography (CBCT) and scanning electron microscopy (SEM). Mesiobuccal roots of 120 freshly extracted maxillary molar teeth were divided into four experimental groups; Hyflex-EDM, OneShape, WaveOne Gold, and Reciproc (n = 30/group). Preinstrumentation scanning was done using CBCT for all samples at coronal one-third (4 mm), middle one-third (8 mm), and apical one-third (12 mm). After cleaning and shaping with standard irrigation protocol, the specimens were again scanned. Canal-centering ability and CT were calculated using pre- and postinstrumentation CBCT values. A scanning electron microscope was used to identify dentinal crack formation. No significant difference was found for CCA by any of the systems at coronal, middle, and apical third, respectively. However, OneShape was found to have better CCA at the coronal third and WaveOne Gold at the middle and apical third. There was a significant difference in canal transportation at the apical third (p = 0.004) with WaveOne Gold having the least CT followed by Reciproc at the apical third. OneShape resulted in more dentinal cracks in the coronal and middle thirds. Also, Hyflex-EDM was better in the apical third. No difference in CCA was observed between the groups. The lowest values for CT were obtained for WaveOne Gold (similar to Reciproc) whereas both rotary files showed higher values for CT. Also, OneShape showed the most dentinal at all levels. Furthermore, Hyflex-EDM and WaveOne Gold produced the least dentinal cracks at all levels. Given that the Reciprocating file system had the least CT and least dentinal cracks, the clinical success rate of root canal treatment (RCT) with the Reciprocating file system can be a better choice to improve the longevity of root canal-treated teeth.

Comparative Evaluation of Root Canal Centering Ability of ProTaper, Mtwo, WaveOne, and Reciproc Using Cone-beam Computed Tomography: In Vitro Study

To compare the centering ability of rotating (ProTaper and Mtwo) and reciprocating (WaveOne and Reciproc) file systems using cone-beam computed tomography (CBCT). Eighty extracted human mandibular molars with curvature within 15-45° were selected and randomly divided into four groups (n = 20): group I (ProTaper), group II (Mtwo), group III (WaveOne), and group IV (Reciproc). The selected teeth were arranged in a template, and pre-instrumentation and post-instrumentation CBCT scans were taken using Kodak Carestream CS 9300 machine. The centering ability was measured in four planes namely, at furcation, 3 mm apical to furcation (coronal), 6 mm apical to furcation (middle), and 3 mm coronal to the apex (apical), wherein dentin thickness was measured from pre- and post-instrumentation CBCT scans and recorded for each canal (mesiobuccal and mesiolingual) separately and statistically analyzed. Mtwo and Reciproc remained better centered followed by WaveOne and least by ProTaper in different-level comparisons. In the mesiodistal dimension (MD) at the 3 mm, 6 mm, and 3 mm apical level, Mtwo and Reciproc showed better centering, meanwhile, in the buccolingual dimension, only in the 3 mm apical level, Mtwo and Reciproc remain better centered. A significant difference was seen between the group and type of canal. Mtwo and Reciproc showed better centered preparation than ProTaper and WaveOne. Significant differences were seen between the groups and types of canal. Root canal instrumentation should maintain the original canal anatomy. The proper enlargement keeping in mind the remaining strength in the tooth structure is essentially decided by how the selected instrument is centered. The alloy used for instrument manufacture and its design (taper, cross-section, and tip) will influence the centered preparation. The type of instrument and the instrumentation techniques should be chosen based on root canal anatomy.

Evaluation of centralization ability and canal transportation of root canals prepared with three commercially available pediatric rotary files.

The complex root canal anatomy of primary root canals is considered to be most challenging. The quality of the root canal preparation plays a significant role in the success of endodontic treatment. Now, there are very few root canal instruments that are capable of cleaning the canal three dimensionally. To evaluate the efficacy of root canal instruments, various technologies have been used; one of the most reliable strategies was cone-beam computed tomography (CBCT). The aim of this study is to compare the centralization ability and canal transportation of three commercially available pediatric rotary file systems using CBCT analysis. Thirty-three extracted human primary teeth with a minimum 7 mm root length were randomly divided into three groups (group I - Kedo-SG Blue, group II - Kedo-S Square, and group III - Pro AF Baby Gold). Biomechanical preparation was done according to the manufacturers instructions. Pre- and postinstrumentation CBCT images were taken for each group to evaluate the remaining dentin thickness thereby assessing the centering ability and the canal transportation ability of different file systems. Significant difference was noticed in canal transportation and centering ability between the three tested groups. Mesiodistal canal transportation was significant at all three levels, whereas buccolingual canal transportation was significant only at the apical third of the root. However, Kedo-SG Blue and Pro AF Baby Gold showed lesser canal transportation compared to Kedo-S Square rotary file system. Mesiodistal centering ability was significant at cervical and apical thirds of the root with Kedo-S Square rotary file system maintaining less canal centricity. All three file systems tested in the study were effective in removing the radicular dentin. However, Kedo-SG Blue and Pro AF Baby Gold rotary file systems showed comparatively less canal transportation and more centering ability than Kedo-S Square rotary file system.

Comparative evaluation of canal transportation and centering ability between 4% and 6% rotary files using cone beam computed tomography — An invitro study

Aim of the study was to evaluate the canal transportation and centering ability of 4% and 6% rotary systems by cone beam computed tomography (CBCT).: Sixty permanent mandibular first molar mesio-buccal canals were chosen and divided into two groups (n=30) according to the bio mechanical preparation method used: Vortex blue and XP Endo Shaper. Following after placed on a customized wax sheet substrate, the samples were scanned using CBCT and then subjected to instrumentation according to the group selected. Then post instrumentation CBCT was taken. Slices from the axial slice were obtained at 3 mm, 6 mm, and 9 mm from the root apex, corresponding to the apical, middle, and coronal thirds, respectively, from both exposures. The results showed that there were no statistically significant differences in canal centering and transportation between both the groups. However vortex blue group showed less transportation and less amount of untouched dentin. It was concluded that " 6% taper group though having higher taper showed better centering ability and less amount ofuntouched dentin and 4% taper file group thoughan adaptive core technology showed more transportation because of its non-uniform expansion to thermal changes.

A comparative evaluation of remaining dentin thickness following biomechanical preparation of teeth using different rotary file systems: An in vitro study.

Aim:The aim of the study is to compare and evaluate the remaining dentin thickness following biomechanical preparation of teeth using different rotary file systems.Materials and Methodology:Sixty noncarious mandibular premolar teeth were collected and decoronated at the level of cementoenamel junction with a diamond disc. All specimens were randomly divided into 5 experimental groups – ProTaper Next (Dentsply Mallifer), Mtwo (VDW, Antaeus, Munich, Germany), RaCe (FKG, La Chaux-de-Fonds, Switzerland), Hyflex electro-discharge machining (EDM) (Coltene-Whaledent, Allstetten, Switzerland), NeoNiTi (Neolix, France) and 1 control group of 10 teeth each. After mounting the samples on a modeling wax sheet, preoperative cone-beam computed tomography (CBCT) scans were taken. Biomechanical preparation of canals was done following the assigned protocol of manufacturers. Postoperative CBCT scans were taken and comparison was carried out with preoperative scans.Statistical Analysis Used:Difference among the groups was analyzed by post hoc Turkey and analysis of variance tests. A P < 0.05 was considered statistically significant for all tests.Results:A comparison of preinstrumentation and postinstrumentation CBCT images revealed ProTaper Next group to remove more dentin at 7 mm as opposed to other groups in mesiodistal direction. However, no statistical difference was evident between ProTaper Next, MTwo, Race, Hyflex EDM, NeoNiTi file systems at 3 mm, 5 mm, and 7 mm in buccolingual direction. A statistically nonsignificant difference was evident between MTwo, Race, Hyflex EDM, NeoNiTi file systems at 3 mm, 5 mm, and 7 mm in both mesiodistal and buccolingual direction.Conclusion:Race file system performed better and removed lesser dentin in both buccolingual and mesiodistal directions. More dentin was removed at the coronal in mesiodistal direction with the use of ProTaper Next, and significant difference was seen between Protaper Next group and other groups in the study.

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.

Cone beam computed tomography assessment of canal transportation, centering ability, and radius change of two single file systems in curved root canals

Objective: assessment the canal transportation and centering ability of two single file systems (Reciproc and Neoniti) in curved mesiobuccal (MB) root canal of natural lower first molars, by cone beam computed tomography (CBCT) scanning. Methods: Forty non-calcified Mesio-buccal root canals with complete formed root and apical curvature of 20-45o and Radius ≤ 15mm were chosen from extracted human lower first molars. The samples were divided based on the instrument (n=20) into two main groups group I (Reciproc R 25/08) and group II (Neoniti R 25/08). Each group has another subdivided based on the motion into (n=10) Subgroup A: reciprocation motion Subgroup B: full rotation motion. The apical transportation, centering ability and radius change were measured by pre- and post-instrumentation CBCT scans by superimposing in four section (2, 4, 6 and 8 mm from apical foramen). Values were recorded, tabulated for each group and statistically analyzed. Results: The ability of instruments to remain centered in prepared canals at 2and 4 mm levels was higher in Neoniti reciprocation in MD dimension. The centering ratio at 6 and 8 mm level and in BL dimension were not significantly different between the tested subgroups. The change of the radius values and percentage produced no significant difference. Conclusion: Both Neoniti and Reciproc systems haven’t significant difference in canal transportation, centering ability and change in curvature radius expect when using reciprocation motion Neoniti produced significantly better results than Reciproc especially in the apical third.

An in vitro Comparative Evaluation of Volume of Removed Dentin, Canal Transportation, and Centering Ratio of 2Shape, WaveOne Gold, and ProTaper Gold Files Using Cone-Beam Computed Tomography.

Objectives:The aim of this study was to compare the shaping ability of three file systems – 2Shape (2S), WaveOne Gold (WOG), and ProTaper Gold – using cone-beam computed tomography (CBCT).Materials and Methods:Forty-five freshly extracted mandibular teeth were chosen and instrumented using the following brands of NiTi files: 2S, WOG, and ProTaper Gold. Pre- and post-instrumentation CBCT imaging was performed to measure mesial and distal distance of the dentin walls and calculate the volume of removed dentin, apical transportation, and centering ratio. A statistical analysis of the data was performed using independent t-test. Statistical significance was set at 5%.Results:There were no significant differences between the 2S and WOG in terms of the total volume of removed dentin, apical transportation, and centering ratio, whereas ProTaper showed a greater significant difference when compared to 2S and WOG.Conclusion:Both 2S and WOG maintained the original canal anatomy better and did not remove excess dentin while chemomechanical preparation as compared to ProTaper Gold. Instruments that use rotary movement achieved an effect similar to that of the reciprocating instruments in relation to change in angle. 2S which is a two-file system and WOG which is a single-file system might perform better clinically and might show enhanced shaping ability with less canal transportation and more centered preparation when compared to ProTaper Gold that is a multiple file-system.

Influence of Motion Pattern on Shaping Ability of Two Single File Systems in Curved Root Canals

Purpose: This study was conducted to compare and evaluate the influence of motion pattern on shaping ability of two single file systems (Reciproc and Neoniti) in severely curved mesiobuccal (MB) root canal of human mandibular first molars using cone beam computed tomography (CBCT) scanning. Materials and Methods: Forty non-calcified Mesio-buccal root canals with mature apices and apical curvature of 20-45o and Radius less than 15mm were selected from extracted human mandibular first molars. The samples were divided according to the instrument (n=20) into group I (Reciproc R 25/08) and group II (Neoniti R 25/08). Each group was subdivided according to the motion (n=10) Subgroup A: reciprocation motion (RM) Subgroup B: full rotation motion (CM). After preparation, the amount of apical transportation, centering ability and radius change were assessed by evaluating pre- and post-instrumentation CBCT scans by superimposing in four section (2, 4, 6 and 8 mm from apical foramen). the significance level was set at P ≤ 0.05. Results: There was no ststistical significant difference in canal transportation among the subgroups at three studied levels (2, 4, and 8 mm from the root apex) (P>0.05) in both Bucco-Lingual and Mesio-Distal directions, but at 6mm level where Neoniti CM peroduced significantly more amount of canal transportation than Neoniti RM in MD direction. The ability of instruments to remain centered in prepared canals at 2 and 4 mm levels was significantly higher in Neoniti RM (P 0.05). The change of the radius values and percentage produced no statistically significant difference. Conclusion: The motion pattern has an impact on the shaping ability of the severly curved root canal. Reciprocation motion enhances transition of the file inside the canal with minimal procedural errors.It seems that the difference between Neoniti and Reciproc is of little importance concerning apical transportation and centering ability and Radius change. Also both files preserve the root canal anatomy.

EFFICACY OF RECIPROC R40 AND REVO-S IN PREPARATION OF OVAL ROOT CANALS- AN EX-VIVO CONE BEAM COMPUTED TOMOGRAPHY STUDY

Aim: To evaluate the efficacy of Revo-S and Reciproc R40 NiTi files in preparation of oval root canals using Cone Beam Computed Tomography (CBCT). Methodology: Forty extracted single rooted premolars were divided into 2 groups (n=20). Group 1 (R-S) were prepared with Revo-S up to size #40/.06. Group 2 (R40) were prepared to the same size with a single file R40. Pre- and post-instrumentation CBCT scanning was done. Calculated parameters were: increase (D) in canal volume and surface area. Transportation, centering ability, and untouched canal areas were tested at 3, 6, 9 mms axial sections. Statistical analyses were made using Mann-Whitney U and Friedman’s test (P ≤ 0.05). Results: Significant increase in D volume (P =.000 and P=.003 for R-S and R40 respectively) and D surface area (P =0.048 and P =0.038 for R-S and R40 respectively) was found for both instrumentation kinematics with no significant differences between them. Canals’ transportation and decreased centering ratio were detected in both groups at all tested levels with insignificant smaller values in the M-D direction. Exception was found at 9mm level where a significantly highest transportation was found in R-S group (P= 0.022). Both instruments left untouched canal areas which were insignificantly greater in R-S group (26.5 ± 8.93% for R40 and 31.7 ± 4.96% for R-S). Conclusions: The tested systems caused small canal transportation with a comparatively better centering for Reciproc R40. Irrespective of the instrumentation kinematic, circumferential preparation of oval canals remains an inherent incapability. CBCT is a valuable tool allowing calculation of the canals’ volume.

Transportation and Centering Ability of Neoniti and ProTaper Instruments; A CBCT Assessment.

Introduction:Transportation is an important iatrogenic endodontic error which might cause failure. This study evaluated the canal transportation caused by Neoniti and ProTaper instruments, using cone-beam computed tomography (CBCT) cross sections. Methods and Materials:This in vitro experimental study was performed on 40 mesiobuccal roots of maxillary first molars. The teeth were scanned with CBCT. They were randomly divided into 2 groups (n=20) that were prepared using either Neoniti or ProTaper files. An endodontist prepared the canal according to the manufacturer’s guidelines. Prepared canals were re-scanned. The pre-instrumentation and post-instrumentation CBCT volumes were sectioned at 1 to 9-mm distances from the apex. The extent of canal dentine removal in mesial and distal directions were measured in each cross-section. Canal transportation and instrument centering ability were estimated based on the extents of root wall removal and were compared in both groups. Results:The groups were rather similar in terms of transportation and centering ability (P>0.05). However, canal preparation on mesial and distal walls was statistically significantly less in the Neoniti group, at most cross-sections. Transportation of both groups was not significantly different (P>0.05). Centering ability of both instruments was not significantly different (P>0.05). Conclusion:Neoniti and ProTaper instruments might have proper centering ability and minimum transportations. Both instruments might cause similar extents of transportation and centering abilities.

Comparative evaluation of effect of rotary and reciprocating single-file systems on pericervical dentin: A cone-beam computed tomography study.

Aim and Objective:The aim of this study is to evaluate and compare the effect of one shape, Neolix rotary single-file systems and WaveOne, Reciproc reciprocating single-file systems on pericervical dentin (PCD) using cone-beam computed tomography (CBCT).Materials and Methods:A total of 40 freshly extracted mandibular premolars were collected and divided into two groups, namely, Group A – Rotary: A1 – Neolix and A2 – OneShape and Group B – Reciprocating: B1 – WaveOne and B2 – Reciproc. Preoperative scans of each were taken followed by conventional access cavity preparation and working length determination with 10-k file. Instrumentation of the canal was done according to the respective file system, and postinstrumentation CBCT scans of teeth were obtained. 90 μm thick slices were obtained 4 mm apical and coronal to the cementoenamel junction. The PCD thickness was calculated as the shortest distance from the canal outline to the closest adjacent root surface, which was measured in four surfaces, i.e., facial, lingual, mesial, and distal for all the groups in the two obtained scans.Results:There was no significant difference found between rotary single-file systems and reciprocating single-file systems in their effect on PCD, but in Group B2, there was most significant loss of tooth structure in the mesial, lingual, and distal surface (P < 0.05).Conclusion:Reciproc single-file system removes more PCD as compared to other experimental groups, whereas Neolix single file system had the least effect on PCD.

CBCT Assessment of Root Dentine Removal by Gates-Glidden Drills and Two Engine-Driven Root Preparation Systems.

Introduction:The aim of this study was to compare the dentine removing efficacy of Gates-Glidden drills with hand files, ProTaper and OneShape single-instrument system using cone-beam computed tomography (CBCT). Methods and Materials:A total of 39 extracted bifurcated maxillary first premolars were divided into 3 groups (n=13) and were prepared using either Gates-Glidden drills and hand instruments, ProTaper and OneShape systems. Pre- and post-instrumentation CBCT images were obtained. The dentin thickness of canals was measured at furcation, and 1 and 2 mm from the furcation area in buccal, palatal, mesial and distal walls. Data were analyzed using one-way ANOVA test. Tukey’s post hoc tests were used for two-by-two comparisons. Results:Gates-Glidden drills with hand files removed significantly more (P<0.001) dentine than the engine-driven systems in all canal walls (buccal, palatal, mesial and distal). There were no significant differences between OneShape and ProTaper rotary systems (P>0.05). Conclusion:The total cervical dentine removal during canal instrumentation was significantly less with engine-driven file systems compared to Gates-Glidden drills. There were no significant differences between residual dentine thicknesses left between the various canal walls.

Efficacy of LA Axxess burs, Gates Glidden drills and Protaper Sx in obtaining straight line access in mesiobuccal roots of mandibular first molars: A cone-beam computed tomography assessment.

Objective:This study aims at cone-beam computed tomography (CBCT) evaluation of the ability of Gates Glidden (GG) drills, Protaper Sx, and LA Axxess burs to produce a straight line access (SLA) in mesiobuccal canals of mandibular first molars.Methodology:Forty-five freshly extracted mandibular teeth with a canal curvature of 10-20° were taken for the study and divided into three groups according to the instruments used for cervical preflaring: Group I (LA Axxess burs), Group II (GG drills), and Group III (Protaper Sx). Pre- and post-instrumentation CBCT images were evaluated for comparing the ability of GG drills, Protaper Sx and LA Axxess burs to produce an SLA in mesiobuccal canals of mandibular first molars.Results:There was no significant change (P = 0.06) in the angle in the preSLA images of LA Axxess Group I (12.37 ± 1.01), GG Group II (13.39 ± 1.74), and Protaper Sx Group III (13.90 ± 1.74). The mean decrease in the angle from preSLA to postSLA was significant for all the three groups (P = 0.0001). However, the mean change was highest in Group I (4.25 ± 1.14), followed by Group II (3.28 ± 1.22) and Group III (2.89 ± 1.53).Conclusion:LA Axxess burs were the most effective in reducing the coronal curvature and produced a straighter access to apical third compared to GG Drills and Protaper Sx.

Influence of motion pattern on apical transportation and centering ability of WaveOne single-file technique in curved root canals.

Background:The aim of this study was to evaluate apical transportation and centering ability of single-file instruments, WaveOne primary, with full rotation versus reciprocation movement using cone-beam computed tomography (CBCT) analysis in curved mesiobuccal (MB) root canal of human mandibular molars.Materials and Methods:Thirty MB canals of mandibular molars were randomly divided into two groups according to the instrument motion (n = 15): Group 1, reciprocation/WaveOne primary; Group 2, continuous rotation/WaveOne primary. After preparation, the amount of apical transportation and centering ability were assessed by evaluating pre- and post-instrumentation CBCT scans in three section (1, 3, and 5 mm from apical foramen). Statistical analysis of the data was performed using Mann-Whitney U-test and Friedman test (α = 0.05).Results:There was no statistically significant difference between two experimental groups in terms of apical transportation and centering ratio at 1, 3, and 5 mm from apical foramen (P > 0.05).Conclusion:Apical transportation and centering ability of WaveOne primary reciprocating instrument did not significantly differ between two motion patterns.

Cone-Beam Computed Tomography Assessment of Root Canal Transportation by Neoniti and Reciproc Single-File Systems.

Introduction:The aim of this in vitro study was to compare the canal transportation of two single-file engine-driven systems, Neoniti and Reciproc, using cone-beam computed tomography (CBCT). Methods and Materials:Forty-five non-calcified roots with mature apices and apical curvature of 15-30 degrees were selected from extracted human maxillary molars for this study. Samples were randomly divided into two groups (n=20) and a control group (n=5) and canal preparation with either system was performed according to manufacturers' instructions. Pre- and post-instrumentation CBCT images were captured and the amount of canal transportation within the files was calculated at levels of 3, 4, and 5 mm from the apex. The independent sample t-test was used to analyze the statistical significance between the two groups. The level of significance was defined at 0.05. Results:Reciproc created more canal transportation compared to Neoniti in both mesiodistal and buccolingual directions. The difference between the two systems was statistically significant in all evaluated distances from the apex (P<0.001). During this study fracture of one file (25/0.08) in the Neoniti group occurred. Conclusion:Neoniti and Reciproc systems have significant difference in terms of creating canal transportation. Reciproc created more canal transportation in buccolingual and mesiodistal dimensions.

Alterations of the Danger Zone after Preparation of Curved Root Canals Using WaveOne with Reverse Rotation or Reciprocation Movements.

Introduction:The aim of this study was to compare the changes that occur in the danger zone (DZ) after preparation of curved mesiobuccal (MB) canals of mandibular first molars with WaveOne instruments in two different movements [reciprocation (RCP) and counter-clockwise rotation (CCWR)] by means of cone-beam computed tomography (CBCT). Methods and Materials:MB canals of 30 mandibular molars were randomly divided into 2 groups (n=15); WaveOne/RCP and WaveOne/CCWR. Pre- and post-instrumentation CBCT images were assessed for changes in the dentin thickness in DZ (2 and 4 mm below the highest point of the root furcation) in both groups. Data was analyzed using the repeated measures ANOVA test. Results:There was no statistically significant difference between two experimental groups in terms of remaining dentin thickness at 2 and 4 mm levels below the highest point of the furcation (P>0.05). Conclusion:The efficacy of WaveOne instrument on changes of the dentin thickness in the DZ was not affected by different file movements.