Canal Centering Research Articles

Comparative Evaluation of Canal Centering Ability between Protaper Rotary and Self Adjusting File in Oval Shaped Canals – A Cone Beam Computed Tomographic Analysis

Comparative Evaluation of Canal Centering Ability between Protaper Rotary and Self Adjusting File in Oval Shaped Canals – A Cone Beam Computed Tomographic Analysis

Morphometry of the human clavicle and intramedullary canal: A 3D, geometry-based quantification.

Midshaft clavicle fractures are a very common occurrence. The current treatment of choice involves internal fixation with superior or anterior clavicle plating, however their clinical success and particularly patient satisfaction are decreasing. The implementation of intramedullary devices is on the rise, but data describing the intramedullary canal parameters are lacking. The aim of this study is to quantify the geometry of the clavicle and its intramedullary canal, and to evaluate the effect of gender and anatomical side. This study used three-dimensional image-based models with novel and automated methods of standardization, normalization, and bone cross-section evaluation. The data obtained in this study present intramedullary canal, and clavicle diameter and center deviation parameterized as a function of clavicle length as well as its radius of curvature and true length. Results showed that both right-sided and female clavicles were shorter and thicker, but only females showed a statistically significant difference in size compared to males (p < 0.0001). The smallest clavicle and intramedullary canal diameters were seen at different clavicle lengths (45% and 52%), suggesting that the narrowest region of intramedullary canal cannot be appreciated based on external visualization of the clavicle alone. The narrowing of the intramedullary canal is of special interest because this is a potential limiting region for surgical planning and intramedullary device design. Furthermore, the location and value of maximum lateral curvature displacement is different in the intramedullary canal, implying there exists an eccentricity of the intramedullary canal center with respect to the clavicle center. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2191-2202, 2017.

Computed Tomography Assessment of Canal Centering Ability Using Hand and Rotary Instruments - an In Vitro Study

Abstract Aim: The present in vitro study aims to evaluate canal preparation comparing centering ability of ProTaper, Mtwo, Wave One, Hand Ni-Ti K-files using Computed Tomography(CT). Materials and Methods: Sixty extracted permanent teeth were selected and decoronated at 11 mm from the apical end. Samples were randomly divided into 4 groups as ProTaper, Mtwo, Wave One, Hand Ni-Ti K-files. Teeth were scanned by CT Scanner. Sectioning was started at 1 mm from the apex up to coronal orifice. Nine levels at 1 mm each were chosen for evaluation in the Computed Tomography. The canals were prepared and a post instrumentation scan was again taken. The pre and postoperative CT images were superimposed at all nine levels. The canal centering ability was calculated. Statistical data was evaluated using One Way Analysis Of Variance test. Results: Amongst the rotary and reciprocal groups the best canal centering ability at the apical third was seen with Wave one. All the three groups behaved similarly in the middle and coronal thirds of the root canal. Conclusion: Keeping in mind the importance of apical third preparation and consistent behaviour in all directions, Wave One may be considered by far the best in the apical third.

Root Canal Surface Strain and Canal Center Transportation Induced by 3 Different Nickel-Titanium Rotary Instrument Systems

IntroductionRoot canal anatomy and canal preparation instruments affect the outcome of endodontic treatment. The purpose of this study was to determine the root surface strain (SS) generated and the extent of canal center transportation during canal shaping using 3 different nickel-titanium instruments. MethodsSimulated root canals in resin blocks (n = 10 per group) were prepared using adaptive rotary motion with twisted files (Twisted File Adaptive [TFA]; SybronEndo, Orange, CA), reciprocating rotary motion with WaveOne (WO; Dentsply Maillefer, Ballaigues, Switzerland) files, and continuous rotary motion with ProTaper Next files (PTN, Dentsply Maillefer). Electrical strain gauges at 3 sites recorded SS real time during canal shaping, and the blocks were scanned by micro–computed tomographic imaging to assess the canal center deviation at 3 sections after root canal instrumentation. The mean maximum SS and the canal center transportation for all groups and sites were derived and analyzed for a possible correlation between them. ResultsAn overall increase in root SS was observed after root canal instrumentation. A significant difference in the induced mean maximum SS between TFA, WO, and PTN at specific sites of curved root canals was observed. A statistically significant difference in the mean distance of canal center transportation was observed among the 3 shaping techniques at the apical section. Finally, the mean maximum SS values induced during canal shaping strongly correlated with canal center transportation in the apical section and the coronal section. ConclusionsThe curved canals prepared using TFA exhibited lower SS and less canal center transportation at the apical section than the WO and PTN systems. SS generated during canal shaping correlated with canal center transportation in a site-specific manner.

Canal Transportation and Centering Ability of ProTaper next versus ProTaper Universal

Canal Transportation and Centering Ability of ProTaper next versus ProTaper Universal

Evaluating Transportation by Comparing Several uses of Rotary Endodontic Files.

To evaluate the frequent use of ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) systems on shaping ability of root canal utilizing Solidworks (2014, Dassault Systemes) software. Thirty-six root canals in clear resin blocks (Dentsply-Maillefer) were allocated into six experimental groups (n = 36). Six new sets of PTN instruments (Dentsply Maillefer, Ballaigues, Switzerland) were used six times to shape the resin blocks. A #15 K-file was inserted to the working length (WL), followed by ProGlider (PG) to create a glide path. Sequential use of PTN instrumentation in a crown-down technique was used to reach size (30/07) apically. Macroscopic photos of the blocks were taken before and after instrumentation, layered by Paint Shop Pro 9 from JascSoftware, and then canal transportation was measured using Solidwork 2014. The data were analyzed by SPSS software version 22. Multivariate statistical analysis general linear model (GLM) was also applied. Bonferroni correction test was used in multiple comparisons and the statistical significance was set to 0.05. There was no difference in canal transportation resulted from utilizing PTN files after six multiple uses; in addition, the PTN files showed ability to maintain the original canal anatomy, especially in the apical level, where lowest total mean value of canal center displacement was seen (3 mm level) (0.019 ± 0.017). ProTaper Next files can be used to prepare single and multiple canals in a single furcated tooth. ProTaper Next nickel-titanium (NiTi) file system is a safe instrument that respects the canal shape, allows practitioners to treat difficult cases with good results, and low risk of separation.

Comparative Analysis of Canal Centering Ability of Different Single File Systems Using Cone Beam Computed Tomography- An In-Vitro Study

The ability of an endodontic instrument to remain centered in the root canal system is one of the most important characteristic influencing the clinical performance of a particular file system. Thus, it is important to assess the canal centering ability of newly introduced single file systems before they can be considered a viable replacement of full-sequence rotary file systems. The aim of the study was to compare the canal transportation, centering ability, and time taken for preparation of curved root canals after instrumentation with single file systems One Shape and Wave One, using cone-beam computed tomography (CBCT). Sixty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20(o) to 35(o) were divided into three groups of 20 samples each: ProTaper PT (group I) - full-sequence rotary control group, OneShape OS (group II)- single file continuous rotation, WaveOne WO - single file reciprocal motion (group III). Pre instrumentation and post instrumentation three-dimensional CBCT images were obtained from root cross-sections at 3mm, 6mm and 9mm from the apex. Scanned images were then accessed to determine canal transportation and centering ability. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference test. It was observed that there were no differences in the magnitude of transportation between the rotary instruments (p >0.05) at both 3mm as well as 6mm from the apex. At 9 mm from the apex, Group I PT showed significantly higher mean canal transportation and lower centering ability (0.19±0.08 and 0.39±0.16), as compared to Group II OS (0.12±0.07 and 0.54±0.24) and Group III WO (0.13±0.06 and 0.55±0.18) while the differences between OS and WO were not statistically significant. It was concluded that there was minor difference between the tested groups. Single file systems demonstrated average canal transportation and centering ability comparable to full sequence Protaper system in curved root canals.

Assessment of canal centering ability and topography of three nickel- titanium rotary systems

Objective: This study aimed to evaluate the canal centering ability and topography of BioRaCeTM (BR), Wizard CD PlusTM (WP), and Wizard NavigatorTM (WN) instruments. Materials and method: mesiobuccal roots of upper first molars were selected and randomly distributed in three groups (n=10), according to the rotary system used for instrumentation. Canal transportation was assessed at 2, 4, 6, and 8 mm from the root apex, by subtracting cone bean computed tomography (CBCT) images taken before and after preparation. The root canal center was marked in pre- and post-preparation images, and the distance between these points was measured in bucco-palatal (BP) and mesio-distal (MD) directions. New instruments were analyzed under scanning electron microscopy (SEM) regarding their surface finishing, topographical features, and surface defects. The SEM images were obtained at the tip of the instrument, and at 5 mm from the tip. Data of the canal centering ability were analyzed by two-way ANOVA (α = 0.05). Results: regardless of root level (2, 4, 6, and 8 mm), all groups presented canal transportation in both directions. Significant differences were not detected (p > 0.05). Surface finishing was regular in the BR group with rounded transitional angle. Cutting edges had a sharp angle in BR and WN groups, while WP instruments had a flattened angle. Conclusion: despite such topographical differences between the rotary instru- ments tested, none of them were able to exactly maintain the original root canal center, and no significant differences were observed among groups. Keywords: Root canal preparation. Endodontics. Scanning electronic microscopy. Rotary instruments.

An Evaluation of Canal Transportation and Centering Ability at Different Levels of Root Canals Prepared by Self - Adjusting File Using Computed Tomography : A Comparative Study

An Evaluation of Canal Transportation and Centering Ability at Different Levels of Root Canals Prepared by Self - Adjusting File Using Computed Tomography : A Comparative Study

Evaluation of a New Filing System's Ability to Maintain Canal Morphology

IntroductionThe manufacturer of the Hyflex CM endodontic files claims the files remain centered within the canal, and if unwound during treatment, they will regain their original shape after sterilization. The purpose of this study was to evaluate and compare the canal centering ability of the Hyflex CM and the ProFile ISO filing systems after repeated uses in simulated canals, followed by autoclaving. MethodsSixty acrylic blocks with a canal curvature of 45° were stained with methylene blue, photographed, and divided into 2 groups, H (Hyflex CM) and P (ProFile ISO). The groups were further subdivided into 3 subgroups: H1, H2, H3; P1, P2, P3 (n = 10). Groups H1 and P1 were instrumented to 40 (.04) with the respective file system. Used files were autoclaved for 26 minutes at 126°C. After sterilization, the files were used to instrument groups H2 and P2. The same sterilization and instrumentation procedure was repeated for groups H3 and P3. Post-instrumentation digital images were taken and superimposed over the pre-instrumentation images. Changes in the location of the center of the canal at predetermined reference points were recorded and compared within subgroups and between filing systems. ResultsStatistical differences in intergroup and intragroup transportation measures were analyzed by using the Kruskal-Wallis analysis of variance of ranks with the Bonferroni post hoc test. There was a difference between Hyflex CM and ProFile ISO groups, although it was not statistically significant. Intragroup differences for both Hyflex CM and ProFile ISO groups were not significant (P < .05). ConclusionsThe Hyflex CM and ProFile ISO files equally maintained the original canal's morphology after 2 sterilization cycles.

Discovering the Past in the Panama Canal Center of Excellence at the University of Florida

Discovering the Past in the Panama Canal Center of Excellence at the University of Florida

Comparison of Air-driven vs Electric Torque Control Motors on Canal Centering Ability by ProTaper NiTi Rotary Instruments

Cleaning and shaping is one of the most important phases in root canal therapy. Various rotary NiTi systems minimize accidents and facilitate the shaping process. Todays NiTi files are used with air-driven and electric handpieces. This study compared the canal centering after instrumentation using the ProTaper system using Endo IT, electric torque-control motor, and NSK air-driven handpiece. This ex vivo randomized controlled trial study involved 26 mesial mandibular root canals with 10 to 35° curvature. The roots were randomly divided into 2 groups of 13 canals each. The roots were mounted in an endodontic cube with acrylic resin, sectioned horizontally at 2, 6 and 10 mm from the apex and then reassembled. The canals were instrumented according to the manufacturer's instructions using ProTaper rotary files and electric torque-control motors (group 1) or air-driven handpieces (group 2). Photographs of the cross-sections included shots before and after instrumentation, and image analysis was performed using Photoshop software. The centering ability and canal transportation was also evaluated. Repeated measurement and independent t-test provided statistical analysis of canal transportation. The comparison of the rate of transportation toward internal or external walls between the two groups was not statistically significant (p = 0.62). Comparison of the rate of transportation of sections within one group was not significant (p = 0.28). Use of rotary NiTi file with either electric torquecontrol motor or air-driven handpiece had no effect on canal centering. NiTi rotary instruments can be used with air-driven motors without any considerable changes in root canal anatomy, however it needs the clinician to be expert.

A methodology to standardize the evaluation of root canal instrumentation using cone beam computed tomography

The evaluation of root canal instrumentation is important to observe the action of endodontic instruments in the root canal walls. Aim: This study introduces a method to standardize the acquisition of images before and after preparing root canals by using cone-beam computed tomography (CBCT). Methods: Sixteen mandibular molars were included in acrylic resin blocks. Samples were inserted in a stable wood box, which was filled with plaster and served as a guide to reinsert the samples. The apparatus was used for the CBCT examination before and after cervical flaring of root canals. The software IcatVision® was used to equalize the images before and after instrumentation with two computers operating at the same time. The measurements between root canal center and the furcation area were determined. The statistical analysis was performed using the t-test for paired samples (a=0.05). Results: The values for dentin thickness in the risk zone before and after root canal flaring with Gates-Gliden drills were 1.096 (± 0.27) mm and 0.742 (± 0.24) (p<0.01), respectively. Conclusions: The proposed method assures the same positioning of the samples before and after root canal preparation. It is extremely important, as any mesiodistal or buccolingual movement can produce a different topogram for comparison procedures.

Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography

The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT). Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections), teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre- and postoperative sections were photographed and analyzed. In G2 (µCT), teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF) system (SybronEndo, Orange, USA), and mesiolingual canals, with the EndoSequence (ES) system (Brasseler, Savannah, USA). Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitney's test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05). The canal transportation results were significantly lower (0.056 mm) in G2 than in G1 (0.089 mm) (p = 0.0012). The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

Comparison of root canal transportation induced by three rotary systems with noncutting tips using computed tomography

The purpose of this study was to compare the shaping ability (apical transportation and straightening) of 3 nickel-titanium rotary instruments (ProTaper Universal, Hero 642 Apical, FlexMaster) with noncutting tips in curved root canals of extracted human teeth using cone beam computed tomography (CBCT). Sixty mesiobuccal root canals of maxillary molars with curvatures of 25° to 47° were equally divided into 3 groups and embedded in silicone impression material. The root canals were scanned using CBCT (Next Generation i-CAT) and after scanning working length was determined with a hand file to preserve the original curvature. After preparation, teeth were placed into their original positions on the silicone impression material and postinstrumentation scans were performed using the same parameters (4-cm field of view at 0.125-mm voxel). Pre- and postinstrumentation images obtained from root cross-sections located 2, 3, and 4 mm above the apical foramen were compared using Adobe Photoshop software. Transportation was measured by superimposition of final and initial images. Any distance (mm) between prepared and anatomic canal centers was defined as apical transportation. Canal curvatures were measured before and after instrumentation using computed tomography and images were exported to ImageJ software. Differences in the degree and radius of curvature were regarded as straightening. Data were analyzed by ANOVA. Mean transportation values were 0.10 ± 0.03 mm for ProTaper Universal, 0.09 ± 0.03 mm for Hero 642 Apical, and 0.07 ± 0.02 mm for FlexMaster, and the differences were not significant. Mean values for straightening among the groups were not significantly different (P > .05). The performances of all instruments were similar. Apical transportation occurred with all the instruments despite their noncutting tips.

Solar radiative heating of fiber‐optic cables used to monitor temperatures in water

In recent years, applications of distributed temperature sensing (DTS) have increased in number and diversity. Because fiber‐optic cables used for DTS are typically sheathed in dark UV‐resistant materials, the question arises as to how shortwave solar radiation penetrating a water column influences the accuracy of absolute DTS‐derived temperatures in aquatic applications. To quantify these effects, we completed a modeling effort that accounts for the effects of radiation and convection on a submersed cable to predict when solar heating may be important. Results indicate that for cables installed at shallow depths in clear, low‐velocity water bodies, measurable heating of the cable is likely during peak solar radiation. However, at higher velocities, increased turbidity and/or greater depths, the effects of solar heating are immeasurable. A field study illustrated the effects of solar radiation by installing two types of fiber‐optic cable at multiple water depths (from 0.05 to 0.8 m) in the center and along the sidewall of a trapezoidal canal. Thermistors were installed at similar depths and shielded from solar radiation to record absolute water temperatures. During peak radiation, thermistor data showed small temperature differences (∼0.003°C–0.04°C) between depths suggesting minor thermal stratification in the canal center. DTS data from cables at these same depths show differences of 0.01°C–0.17°C. The DTS differences cannot be explained by stratification alone and are likely evidence of additional heating from solar radiation. Sidewall thermistor strings also recorded stratification. However, corresponding DTS data suggested that bed conduction overwhelmed the effects of solar radiation.

In-rive study of rotational characteristic of human lumbar segments

Objective To measure the vertebral rotational centers in sagittal and transverse plane. These data may be quite valuable for the design of artificial disc. Methods Ten healthy volunteers of 40-60 years old were recruited under IRB approval and informed consent. Three-dimension lumbar spine models of L_2, L_3 and L_4 were reconstructed from MR scans. Spine motions were then reproduced using combined dual fluoroscopic imaging system (DFIS) and MR scan technique during flexion-extension and left-right twisting of the body. Based on the geometrical features of the vertebrae, ranges of motion (ROM) of 3 representative lo-cations were measured from anterior to posterior, the vertebral body center, the spinal cord canal center and the spinous process tip. Rotational centers of the vertebral segments were then located by calculating the point of zero ROM. Results Motion patterns: The ROMs of L_2 with respect to L_3 (L_(2,3)) and L_(3,4) increased pro-portionally from anterior to posterior locations. During flexion-extension motion, the vertebral body center moved within a range of 0.6 mm, while the spinous process tip moved within 7.5 mm in the sagittal plane. During left-right twisting, the vertebral body center moved within 1.0 mm, while the tip moved within 1.6 mm in the transverse plane. No statistical differences were found in the ROMs between L_(2,3) and L_(3,4). Rotational centers: the rotational centers of flexion-extension in sagittal plane for both L_(2,3) and L_(3,4) segments were located at posterior one-third of the vertebral body. The rotational centers of both L_(2,3) and L_(3,4) segments were located approximately 30 mm anterior to the front edge of the vertebral body. Conclusion The anterior portion of the vertebrae was found to have smaller ROM than the posterior portion. The vertebra rotates with the center of rotation located at approximately the posterior one-third of the vertebral body in sagittal plane. However, the vertebra rotates in transverse plane with respect to a point about 30 mm in front of the vertebra. The data indicated that the different portions of the vertebra have distinct motion characters during different motions. Key words: Lumbar vertebrae; Rotation; Intervertebral disk; Prosthsis design

Three-dimensional analysis of the intramedullary canal axis of tibia: clinical relevance to tibia intramedullary nailing

The aim of this study was to evaluate the appropriate insertion point for a tibial intramedullary nail by measuring the intramedullary canal axis of the tibia in three dimensions. Forty-three pairs (14 males and 29 females) of cadaveric low extremities (mean age 51 years, range 21-60 years) were analyzed to evaluate the appropriate insertion point for a tibial intramedullary nail by measuring the intramedullary canal axis of the tibia in three dimensions. Computed tomography was performed on 86 lower extremities from the hip to the ankle on cadavers. The location of the intramedullary canal axis of the tibia passing through the tibial plateau, the canal axis center (CAC), was measured. The correlations between the lateral tibial spine (LTS) and the mediolateral coordinates of the CAC were analyzed. The CAC was located at 56.5% distance from the medial cortex. On average, the CAC was located 1.1 mm medial from the LTS. The mean length from the surface center to the CAC was lateral 4.5 mm. The appropriate insertion point for a tibial nail was the slightly medial aspect of the LTS. However, it led to the point with a broad range, increasing the necessity to take individual variations into consideration.

Comparison of shaping ability using LightSpeed, ProTaper and Hybrid technique in simulated root canals

The purpose of this study was to compare the shaping abilities of LightSpeed, ProTaper-Universal, and hybrid technique using S-series of ProTaper-Universal and LigthSpeed. The 72 simulated root canals of J-shape were used and classified as flowing 3 groups according to the instrumentation methods; Group P of 24 canal blocks were prepared with ProTaper-Universal, Group L was prepared with LightSpeed, and Group H was prepared with hybrid technique (initial shaping with ProTaper-Universal SI and S2 and apical shaping with LightSpeed from #25 to #50). A second-year resident of Endodontic department prepared the resin block canals to apical size #50 (F5 in Group P). The time lapses for instrumentation and the reduction of root canal curvature after shaping were measured. The pre- and post-instrumented root canals were scanned and superimposed to evaluate and calculate the increased canal width and apical centering ratio. The results were as followings: Group Land H showed significant less instrumentation time than Group P (p &lt; 0.05). The ProTaper system showed greater reduction of root canal curvature and working length diminishment than other methods (p &lt; 0.05). LightSpeed system showed best canal curvature preserving characteristics. The Group P had greater instrumented widths at all levels examined (p &lt; 0.05). Group L and Group H showed lower centering ratio (ability to preserve the canal center; the lower ratio means the better canal center preservation) than Group P (p &lt; 0.05). Group H had the lowest centering ratio at the 1 mm level.

Parallel post‐space preparation in different tooth types ex vivo: deviation from the canal centre and remaining dentine thickness

To determine the deviation of parallel-sided twist-drills during post-channel preparation and relate this to tooth type and position. Human teeth with single root canals were selected: maxillary second premolars (group i); maxillary lateral incisors (group ii); mandibular canines (group iii); mandibular first premolars (group iv; all groups n = 16). The teeth were reduced to 17 mm length by sectioning the crown, and the root canals prepared and filled. Microradiographs were made in two directions. The teeth were individually embedded in a gypsum jaw and placed in a phantom head. Two operators performed parallel post-space preparation (12 mm length, 1.25 mm diameter) to the following protocol: gutta-percha removal with Gates Glidden drills numbers 2 and 3 and post-space enlargement with parallel drills numbers 3, 4 and 5, consecutively. Subsequently, microradiographs were re-exposed. The original and post-operative microradiographs were digitized and superimposed, and deviation of the post-space from the filled canal and remaining dentine thickness measured. Overall, the mean deviation was 0.07 mm to the mesial (95% CI: 0.01-0.12), and 0.27 mm to the buccal (95% CI: 0.18-0.35). Group ii had significantly more buccal deviation than other groups (P = 0.004-0.008). A remaining dentine thickness of <0.5 mm occurred 16 times in 14 teeth, and of <1 mm occurred 97 times in 52 teeth. Deviation during parallel post-preparation was common, predominantly in mesial and buccal directions, especially in maxillary incisors. This deviation increased the risk of perforation considerably.