Angle Of Canal Curvature Research Articles

Dynamic analysis of a NiTi rotary file by using finite element analysis: Effect of cross-section and pitch length.

This study assessed stress distribution, maximum stress values and fatigue life of experimentally designed NiTi rotary files with different cross-sectional geometry and pitch length using finite element analysis (FEA). Four cross-sectional shapes (Convex triangle, S-shaped, Triple helix and Concave triangle) and two pitch lengths (2 mm and 3 mm) were tested in simulated root canals with curvatures of 30°, 45° and 60°. The FEA results indicated that convex triangle and triple helix geometries exhibited lower stress values compared to the S-shaped and concave triangle designs. Increasing the canal curvature angle resulted in higher stress values, with the S-shaped instrument showing the most significant increase (up to 12%). Instruments with shorter pitch lengths showed more even stress distribution enhancing fatigue life. The maximum stress was concentrated 5-8 mm from the tip, varying across cutting edges, with S-shaped sections experiencing the lowest forces but higher stress due to lower moments of inertia.

A Cone-Beam Computed Tomographic Analysis of Mesiobuccal Root Canals of Maxillary First Molars.

The maxillary first molar is crucial for proper bite formation and jaw positioning in adulthood. The prevalence of dental caries in the study's sample population suggests it is a common candidate for endodontic therapy. Multiple studies have shown that the canal and root morphology of the maxillary first molar are abnormal. The distobuccal and palatal roots of 286 maxillary first molars were removed at the furcation. The mesiobuccal roots were then imaged using cone-beam computed tomography (CBCT) on all specimens. The specimens were analyzed in comparison with one another. The following factors were studied. The number and arrangement of canals, as described by Vertucci; the presence or absence of an isthmus, as described by Kim; the canal curvature angle, as measured by the Schneider method; characteristics such as calcified segments, lateral canals, and an apical delta.For the flow analysis, CBCT was utilized to examine the root channel architecture of 286 mesiobuccal (MB) permanent maxillary first molar. Type I canal arrangement was found in 51.6% of teeth, Type II in 33.3%, Type III in 4.6%, Type IV in 4.2%, Type V in 2.5%, and Type VII in 1.5%. Type I, II, III, and V isthmus were each present in 26%, 6.7%, 9.5%, and 10.2% of the samples, respectively. Teeth with MB1 canal angulations of 0-20 degrees, 21-40 degrees, and more than 40 degrees were found in 56, 188, and 41 teeth, respectively. From 0 to 20 degrees, 21 to 40 degrees, and more than 40 degrees, 15 teeth, 88 teeth, and 25 teeth, respectively, had angulations in their MB2 canals. Only 9.8% of the samples had lateral canals, while 16.1% had both accessory canals and apical deltas. There were 19 cases with calcified segments in the coronal third of the MB1 canal and 13 cases in the middle third. There were no calcifications at the distal end of the MB1 canal. Thirteen of the specimens showed calcification only in the most caudal third of the MB2 canal, whereas the middle and distal thirds were uncalcified. Utilizing a noninvasive approach, a CBCT scan has the capacity to provide valuable insights into the root canal configuration.

Effect of the temperature of sodium hypochlorite on the cyclic fatigue resistance of ProTaper Gold rotary files.

Instrument fracture is one of major challenges during root canal treatment. In order to reduce such errors, it seems necessary to investigate the effects of potentially impactful factors. One of such factors could be the temperature of an agitator. This study examined the effects of different temperature of the sodium hypochlorite solution on the cyclic fatigue resistance of ProTaper Gold (PTG) rotary files. Forty-five PTG S1 rotary files were tested in a metal block that simulated a canal curvature angle of 60° and a curvature radius of 5 mm. They were randomly divided into 3 groups of 15 according to sodium hypochlorite temperatures of 22°C (group 1), 4°C (group 2) and 37°C (group 3). Files from each group were rotated at 300 rpm in the block at each temperature. The number of cycles to fracture was calculated and the fragment length was measured. The fractured surfaces were examined by means of scanning electron microscopy (SEM). The statistical analysis was completed using the Kolmogorov-Smirnov and Kruskal-Wallis tests, and the IBM SPSS Statistics for Windows software, v. 22.0, at a significance level of 5%. The cyclic fatigue resistance of the PTG rotary files was not significantly affected by the temperature of sodium hypochlorite (p > 0.05). Increasing the temperature of sodium hypochlorite to 37°C or decreasing it to 4°C did not significantly affect the cyclic fatigue resistance of PTG rotary files.

Shaping ability of 2Shape and NeoNiTi rotary instruments in preparation of curved canals using micro-computed tomography

BackgroundVarious systems of nickel-titanium (NiTi) instrument have long been commercially available. However, the preparation of narrow and curved root canals has always been challenging. The purpose of this study was to compare the shaping ability of two NiTi systems (2Shape and NeoNiTi) in severely curved root canals with different morphological patterns using micro-computed tomography (Micro-CT).MethodsA total of 22 human extracted permanent teeth of mandibular first molars, with the exact mesial angle of curvature of 25 and 35 degrees, according to Schneider’s technique, were distributed randomly into two groups (group I: 2Shape, group II: NeoNiTi) based on the rotary system used (n = 22). The groups were subdivided into two subgroups corresponding to the angle of canal curvature (25° and 35°) (n = 11). Canals were scanned using Micro-CT pre- and post-preparation to assess the volume of dentin removed; canal transportation; and canal centering ratio at 3, 6, and 9 mm from the apex. The Mann–Whitney U test was utilized to determine any significant differences between the two systems. The level of statistical significance was set at p < 0.05.ResultsThere was no significant difference between the two groups in volume of dentin removed; canal transportation; and centering ability for 25° and 35° canal curvatures at 3, 6, and 9 mm from the apex (coronal, middle, and apical) thirds (p > 0.05). At the middle third, the NeoNiTi group demonstrated a statistically significant increase in volume of dentin removed for 35° canal curvatures compared to the 2Shape group.ConclusionWithin the limitation of our in vitro study, 2Shape and NeoNiTi systems with severely curved canals were confirmed to be relatively safe in preparation and to respect original canal anatomy. Nevertheless, NeoNiTi instruments produced more centered preparation and minimal canal deviation compared to the 2Shape system.

Evaluation of the Shaping Ability of Three Thermally Treated Nickel–Titanium Endodontic Instruments on Standardized 3D-printed Dental Replicas Using Cone-Beam Computed Tomography

Background and Objectives: The aim of the present study is to compare the efficacy of three root canal preparation systems in the shaping of 3D-printed root canal replicas of single rooted teeth. Materials and Methods: Sixty 3D-printed root canal replicas were produced and divided into three groups, each consisting of twenty samples. Each group was shaped with a different instrument: Reciproc Blue R25/08 (VDW GmbH, Munich, Gemany), WaveOne Gold Primary 25/07 (Dentsply Sirona, Ballaigues, Switzerland), and ProTaper Gold F2 25/08 (Denstply Sirona). To ensure the reproducibility of pre- and post-operative CBCT images of the root canals, the endodontic printed replicas were placed in a mould of silicon impression material. A cone-beam computed tomography (CBCT) software was used to compare pre- and post-instrumentation images collected at three levels of the root canal length: 3, 6, and 9 mm from the apical foramen. The amount of transportation, centring ability, and curvature angle after shaping were evaluated for each system. The results were statistically analysed and compared using one-way analysis of variance (ANOVA). Results: Regarding the transportation of the root canal after shaping, significant differences between groups at 3 mm (p = 0.010721) and 6 mm (p = 0.000046) were recorded in the mesio-distal direction, while in the bucco-lingual significant differences were only observed at 6 mm (p = 0.000554). Reciproc Blue removed more dentin from the mesial and buccal wall of the root canal. When evaluating the centring ability of the three systems, significant differences were observed between the groups at the level of 9 mm (p = 0.037258) in the mesio-distal direction, and at the level of 6 mm (p = 0.038197) in the bucco-lingual direction. Significant differences of the canal curvature angle after shaping were also observed between groups (p = 0.000001). Reciproc Blue straightened the curvature the most, while ProTaper Gold the least. Conclusions: All systems produced minor root canal transportation. No instrument was able to achieve a perfect centring preparation of the root canal. All systems produced a small degree of root canal straightening.

Plywood Jig—A New Technique for Root Canal Curvature Measurement

The successful outcome of endodontic treatment is dependent on complete cleaning, shaping as well as three dimensional obturation of the root canal system. A conventional radiograph is a two-dimensional replication of a three-dimensional object and does not provide any conclusive evidence for canal curvatures. An accurate knowledge of the tooth anatomy and curvature is essential to avoid procedural errors. 100 freshly extracted human teeth were used in this study. Digital images were obtained using the plywood JIG and Schneider’s technique. These images were analyzed using the VixWin Pro digital image analyzing software (Gendex system). Statistical analysis was done using paired t test. The canal curvature average values measured using Jig method and Schneider method for mandibular teeth are 28.23° (±9.96) and 22.07° (±9.46) respectively. The smallest/largest curvature angles measured using Jig method and Schneider technique are 12/52° and 8/44° respectively. Canal curvature average values measured using Jig method and Schneider method for maxillary teeth were 23.40° (±11.36) and 19.23° (±11.94) respectively. The smallest/largest average curvature angles measured using Jig method, Schneider technique were 9/70° and 5/72° respectively. The values of the canal curvature angle obtained during routine radiographs in clinics have lower curvature angle and higher radius values as compared to the values obtained by this innovative JIG technique. Therefore, a clinician should always keep in mind the difference while measuring the curvature angle on radiographs during root canal treatment.

Root canal curvature as a prognostic factor influencing the diagnostic accuracy of radiographic working length determination and postoperative canal axis modification: an in vitro comparative study

BackgroundRadiographic analysis of tooth morphology is mandatory for accurate calibration of the degree of canal curvature angle and radiographic working length to its real dimensions in case difficulty assessment protocols. This study aimed to determine the impact of the degree of root canal curvature angle on maintaining the real working length and the original canal axis of prepared root canals using a reciprocating rotary instrumentation technique.MethodsRadiographic image analysis was performed on 60 extracted single-rooted human premolar teeth with a moderate canal curvature (10°–25°) and severe canal curvature (26°–70°). Working length and longitudinal canal axis were determined using cone-beam computed tomography (CBCT) and digital periapical radiography. The real canal length was determined by subtracting 0.5 mm from the actual canal length. Root canals were prepared using the WaveOne Gold reciprocating file (Dentsply Maillefer, Ballaigues, Switzerland).ResultsThere was no significant relation of the degree of canal curvature angle to the accuracy of radiographic working length estimated on CBCT and digital periapical radiographic techniques (P > 0.05). Postinstrumentation changes in the original canal axis between moderate and severe canal curvature angles, assessed on CBCT and periapical digital radiographic images were statistically non-significant (P > 0.05).ConclusionsA standardized digital periapical radiographic method performed similarly to the CBCT technique near to its true working length. No significant interaction exists between the diagnostic working length estimation, postoperative root canal axis modification, and the degree of canal curvature angle, using reciprocating rotary instrumentation technique.

Numerical simulation and experimentation of endodontic file using Taguchi DoE

The endodontic file is a tapered, needle shape body used for the preparation of curved human root canals. During the preparation, process files get failed due to the locking action offered by the canal wall. The present study aimed to find the fatigue life of endodontic files at 23°, 33° and 43° root canal curvature angles. Four brands of files were selected for the present study viz. Hyplex CM, Pro-Taper Next, Hero Shaper, Pro-File Vortex. The strain life analysis done using ANSYS showed that the Hyplex CM file gives the highest fatigue life at 23°, 33° and 43° root canal curvature angles. Therefore, Hyplex CM file was selected for DoE Taguchi Optimization study. Each experimental reading was conducted on X Smart Plus experimental setup under purely rotary and combined reciprocating-rotary motion, at 500 rpm, 600 rpm and 700 rpm and 23°, 33° and 43° root canal curvature angles. Hyplex CM file given maximum fatigue life at 23° root canal curvature angle and 500 rpm speed of rotation. But if file motion is combined rotary-reciprocating, life reduces. The ANNOVA study showed that P-value and significance F are very small, which represented that the regression model is effective.

Canal transportation using Mani GPR or HyFlex NT during the retreatment of curved root canals: A micro-computed tomographic study.

This study assessed the apical transportation using Mani GPR or HyFlex NT during the retreatment of curved root canals. Thirty-eight roots were analysed using micro-CT for the comparison of apical transportation produced by two retreatment systems. Longitudinal transportation, horizontal transportation, variation in the canal angle of curvature and variation in the canal/root width ratio were analysed. Longitudinal transportation was frequently observed, regardless of the system used. The canals retreated with Mani GPR showed a significantly higher horizontal transportation at 1mm from the root apex (P<0.01) and greater variation of the canal curvature angle (P<0.01). The canal/root width ratio was similar between groups (P>0.05). In conclusion, longitudinal transportation occurred more frequently in the mesial canal walls. Mani GPR showed greater horizontal transportation at 1mm short of the apex, and higher variation of the canal curvature angle compared with HyFlex NT.

COMPARING THE EFFECTIVENESS OF HYFLEX ROTARY AND HAND – OPERATED&amp;NBSP; INSTRUMENTS IN PREPARING MESIO-BUCCAL ROOT CANALS OF MANDIBULAR PERMANENT FIRST MOLARS

Objectives: To compare the effectiveness of Hyflex rotary and NiTiflex hand-operated instruments in regard to 4 parameters of root canal preparation: the working time, the alteration of canal curvature and working length, obturating efficacy. Materials and methods: A total of 20 mesio-buccal root canals of mandibular first molars were randomly divided into two similar groups. Group 1 root canals were prepared with Hyflex rotary files according to the manufacter’s instructions. Group 2 with NiTi manual instruments in crown-down technique. Based on radiographs taken prior to instrumentation with the initial instruments inserted into the canals, the 2 groups were balanced with respect to the angle of canal curvature and working length. Canals were prepared using a crown - down preparation technique as instructed by the manufacturer. Group 1 was prepared by rotary Hyflex files and group 2 was prepared by NiTiflex hand-operated instruments. The assessment of changes of canal curvature and working length was based on radiographs taken prior and post instrumentation. The time required for canal preparation was recorded for each specimen. Postoperative teeth were examined clinically and radiographically after 1 week and 3 months. Research design was prospective clinical trials, group comparison. Data was statistically analysed using the SPSS 16.0 software. Results: Rotary Hyflex files prepared significantly faster and maintained the original canal curvature better than hand - operated Nitiflex files (p &lt; 0.05). There was no significant differences in maintaining initial working length of two groups (p &gt; 0.05) and both hand NiTiflex and rotary Hyflex instruments showed 1 case of ledge formation for each, 1 NiTiflex file separation and no perforation or apical transportion. Three-month clinical results were equal: in rotary Hyflex group, 90% teeth of successful result, 10% teeth in suspect; in NiTiflex hand-operated group, 80% ratio of successfully- treated teeth, 10% suspect and 10% failing result. Conclusions: Under the conditions of this clinical study, both instruments were safe to use, showed equally efficacy in preparing root canals and endodontic clinical results. However, rotary Hyflex significantly reduced working time and respected original canal curvature better than hand–operated NiTiflex files, with higher treatment cost from 9 to 10 times. Key words: cleaning, shaping, root canals, rotary, canal curvature

Cyclic Fatigue Resistance of XP-Endo Shaper, K3XF, and ProTaper Gold Nickel-titanium Instruments

IntroductionThe aim of this study was to compare the cyclic fatigue resistance of the ProTaper Gold (PTG; Dentsply Maillefer, Ballaigues, Switzerland), K3XF (SybronEndo, Orange, CA), and XP-endo Shaper (FKG Dentaire, La Chaux-de-Fond, Switzerland) nickel-titanium rotary instruments at intracanal temperatures. MethodsEighteen XP-endo Shaper (30.01), 18 K3XF (30.04), and 18 PTG F3 (30.09v) instruments were used to test the cyclic fatigue resistance at an intracanal temperature of 35° ± 2°C. The instruments were tested in a metal block that simulated a canal curvature angle of 60° and a curvature or radius of 5 mm. All instruments were operated until fracture occurred, and then the number of cycles to failure was calculated. The lengths of fractured fragments were measured with a digital caliper. The data were analyzed statistically using 1-way analysis of variance and the Tukey post hoc test with significance set at P < .05. ResultsThe XP-endo Shaper instruments showed a significantly higher number of cycles to fracture than the K3XF and PTG instruments (P < .05). There was no difference between the PTG and K3XF instruments (P > .05). ConclusionsThe XP-endo Shaper instruments exhibited greater cyclic fatigue resistance compared with the other instruments at the intracanal temperature.

Canal shaping of different single-file systems in curved root canals

Background/PurposeThis study compared maintenance of canal anatomy, occurrence of apical transportation, and working time observed after instrumentation with One Shape New Generation rotary system (Micro-Mega), with those observed after instrumentation with Reciproc (VDW) and WaveOne (Dentsply-Maillefer) reciprocating systems. Materials and methodsThe mesial canals of 45 mandibular molars (curvature angles between 35° and 45°) were selected. Specimens were randomly divided into three groups, and canal preparations were performed using One Shape, Reciproc, or WaveOne systems (size #25). A digital double radiographic technique was used to determine apical transportation and change in angle of curvature. Also, working time and instrument failures were recorded. Data were statistically analyzed. ResultsDuring preparation, no file fractured. No statistically significant differences were found among groups. No system showed a significantly faster preparation time than others (P>0.05). All instruments maintained the original canal curvature well and were safe to use. ConclusionBoth continuous rotary instrument and reciprocating systems did not have any influence on the presence of apical transportation or caused an alteration in angle of canal curvature.

Comparison of the shaping characteristics of Neolix and Protaper Universal systems in preparation of severely-curved simulated canals.

BackgroundThe aim of this in vitro study was to compare the shaping characteristics of two types of nickel-titanium endodontic file systems with regard to the following parameters: Canal straightening, Canal deviation and Instrumentation time.Material and MethodsFifty severely curved canals simulated in resin blocks were prepared to an apical size 25 using Protaper Universal orNeolix systems (n=25 canals/group). The angle of canal curvature was determined before and after instrumentation. Pre- and post-operative images were superimposed to determine any canal deviation. The instrumentation time was also recorded. The data were statistically analyzed by using independent sample t-test and the Mann-Whitney U-test.ResultsThere were no significant differences between the groups in terms of the change in canal angle (P > 0.05). The Neolix system produced less canal deviation at 7 of the 12 measuring points (p<0.05). The Neolix system also required less instrumentation time (p<0.05).ConclusionsBoth rotary systems were capable of maintaining the original curvature of the root canal; however, the Neolix system resulted in less canal deviation as well as shorter instrumentation time. Key words:Apical foramen,canal transportation, nickel-titanium instruments, Protaper Universal, root canal preparation.

A COMPARATIVE STUDY OF APICAL TRANSPORTATION AND STRAIGHTENING OF TWO ROTARY NICKEL-TITANIUM SYSTEMS WHEN USING FINAL APICAL BRUSHING

INTRODUCTION: Apical transportation results in an inadequately clean apical area and makes apical seal more difficult thus affecting the final outcome and may lead to failure. OBJECTIVES: The aim of this study was to compare between the effect of two rotary nickel titanium systems after using final apical strokes on canal transportation and apical straightening of the canal. MATERIALS AND METHODS: Sixty mesiobuccal canals of extracted mandibular first molars with root canal curvature angle (25 to 45 degree) were selected. Canals were divided into two groups (n=30). In group I canals were prepared with OneShape file, while in group II, canals were prepared with Revo-S system. Each group was then sub-divided into two sub-groups according to the motion used (pecking or circumferential filing). Sub group Ia (OneShape file) and sub group Ib (Revo-S system) were prepared with pecking motion while sub group II an and sub group II b were prepared with circumferential filing motion. A radiographic platform was used to obtain accurate radiographs. All specimens were radiographed from proximal and mesiodistal views. To measure apical transportation, the pre and post-instrumentation radiographs were exported from the Kodak software into Photoshop program. Then a grading system was used to assess the amount of transportation. Based on apical curvature measured before and after instrumentation (using Image J program), canal straightening was determined as the difference between these two measurements. RESULTS: Regarding apical transportation, no statistical significance was found between both groups and the sub groups. Apical straightening was evaluated, and no statistical significance was found between the groups. However, circumferential filing produced more straightening. CONCLUSIONS: OneShape file and Revo-S system maintained the original canal curvature with no significant differences between the files. Circumferential filing motion with both systems resulted in higher values of straightening when compared to pecking motion.

Prevalence and morphometric analysis of three-rooted mandibular first molars in a Brazilian subpopulation.

ABSTRACTThe knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present.Objectives:To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT) and to analyze the anatomy of mandibular first molars with three roots through micro-CT.Material and Methods:CBCT images of 116 patients were reviewed to determine the prevalence of three-rooted first mandibular molars in a Brazilian subpopulation. Furthermore, with the use of micro-CT, 55 extracted three-rooted mandibular first molars were scanned and reconstructed to assess root length, distance between canal orifices, apical diameter, Vertucci's classification, presence of apical delta, number of foramina and furcations, lateral and accessory canals. The distance between the orifice on the pulp chamber floor and the beginning of the curvature and the angle of canal curvature were analyzed in the distolingual root. Data were compared using the Kruskal-Wallis test (α=0.05).Results:The prevalence of three-rooted mandibular first molars was of 2.58%. Mesial roots showed complex distribution of the root canal system in comparison to the distal roots. The median of major diameters of mesiobuccal, mesiolingual and single mesial canals were: 0.34, 0.41 and 0.60 mm, respectively. The higher values of major diameters were found in the distobuccal canals (0.56 mm) and the lower diameters in the distolingual canals (0.29 mm). The lowest orifice distance was found between the mesial canals (MB-ML) and the highest distance between the distal root canals (DB-DL). Almost all distal roots had one root canal and one apical foramen with few accessory canals.Conclusions:Distolingual root generally has short length, severe curvature and a single root canal with low apical diameter.

Evaluation of a New Nickel-Titanium System to Create the Glide Path in Root Canal Preparation of Curved Canals

IntroductionNickel-titanium rotary instruments recently have been introduced with the purpose of creating an initial glide path. The purpose of this study was to compare the maintenance of canal anatomy, the occurrence of apical transportation, and the working time observed using mechanised instrumentation with the new G-File rotary system (Micro-Mega, Besançon Cedex, France) with those observed using instrumentation with the PathFile system (Dentsply Maillefer, Ballaigues, Switzerland) and manual instrumentation with K-type files (Micro-Mega) to create a glide path in curved root canals. MethodsThe mesial canals of 45 mandibular molars (with curvature angles between 25° and 35°) were selected. The specimens were randomly divided into 3 groups with 15 canals each, and canal preparations were performed by an endodontist using #12-17 G-File rotary instruments (group GF), #13-16-19 PathFile rotary instruments (group PF), and #10-15-20 K-type stainless steel manual files (group M). A digital double radiographic technique was used to determine apical transportation and the change in the angle of curvature. The working time was also calculated. ResultsNo statistically significant differences in the angle of canal curvature and apical transportation were found between the groups. However, concerning the working time, specimens from the group who underwent canal preparation using #12-17 G-File rotary instruments achieved significantly lower mean values when compared with the other 2 groups, whereas the group who underwent canal preparation using the #10-15-20 K-type stainless steel manual files had the highest values. ConclusionsThe G-File rotary instruments, the PathFile system, and the manual instruments did not have any influence on the occurrence of apical transportation nor did they produce a change in the angle of canal curvature. The G-File instruments seemed to be the most rapid system in creating a safe glide path.

Effectiveness of a Manual Glide Path on the Preparation of Curved Root Canals by Using Mtwo Rotary Instruments

Introduction Nickel-titanium rotary instruments reduce procedural errors and the time required to finish root canal preparation. The goal of this study was to evaluate the effectiveness of a manual glide path on the preparation of curved root canals with Mtwo rotary system. Methods Forty buccal root canals with angles of curvature between 25 to 76 degrees were randomly divided into 4 groups (n = 10); 2 groups were instrumented with Mtwo instruments to the full length, and in the other 2 groups a glide path with #08-15 K files was performed before instrumentation with Mtwo system. Digital double radiographic technique was used to determine apical transportation and the change in angle of curvature. Also working time was calculated. Results No statistically significant differences in the angle of canal curvature, apical transportation, and the working time were found between groups with glide path and no glide path. No significant differences were found when comparing the results of 3 variables between degrees of curvature. Conclusion The use of a manual glide path before Mtwo rotary system did not influence the apical transportation in curved root canals.