Curved Root Canals Research Articles

Features of endodontic treatment of teeth with curved root canals according to a survey of dentists

Purpose: to identify difficulties of endodontic treatment of teeth with curved root canals according to a survey of dentists. Materials and methods: 90 dentists (26 men, 64 women) participated in the survey. 68 people had a therapeutic certificate, 19 people had an orthopedic certificate, 10 people had a surgical certificate, 6 people had a certificate in pediatric dentistry, and 43 people had a certificate in general dentistry (some respondents indicated that they had several certificates). The average age of respondents is 32 years (23–60). The interviewed dentists conduct practical work in public medical institutions, private dental clinics, and rented offices. The questionnaire included 20 questions (6 questions were aimed at collecting demographic data, 14 questions were aimed at obtaining information about the treatment of teeth with curved root canals). The questionnaire was submitted electronically to Google Forms. Statistical analysis of conjugacy tables using the Pearson chi-square test was performed using the program StatTech (Russia). Results: this survey reliably showed that dentists often experience difficulties in treating teeth with curved root canals. Dentists working in state institutions are significantly more likely to note that the rubberdam latex interferes (p= 0.049) and the clamp bow (p= 0.029) compared to doctors working in other institutions. Dentists working in a rented office are significantly more likely to report that a rubberdam latex interferes (p= 0.024) compared to doctors working in other institutions. Dentists who report difficult access when working with the mesial buccal canal of the lower molars are significantly more likely to note that a rubberdam latex interferes (p= 0.036). Dentists who use the approach «first negotiation to the working length – then coronal flaring» significantly more often experience difficulties when working with the mesial buccal first canal of the upper molars. Conclusions: the results of the survey demonstrated a number of differences in the performance of endodontic treatment of teeth with curved root canals. Based on the survey, statistically significant relationships were identified between some work features and difficulties encountered by doctors at the stages of treatment.

Influence of Root Canal Size and Curvature on Insertion Depth of Three Different Endodontic Irrigation Needles

Influence of Root Canal Size and Curvature on Insertion Depth of Three Different Endodontic Irrigation Needles

Comparative analysis of the effectiveness of mechanical treatment of root canals by various Ni-Ti file systems

INTRODUCTION. One of the main stages of successful endodontic treatment is high-quality mechanical treatment of root canals. А large number of various rotary Ni-Ti files in the dental market poses a difficult choice for the doctor, especially in the context of import substitution. It is necessary to have knowledge about the effectiveness of different system of instruments in a particular clinical case. AIM. With the help of scanning electronic mycoroscopy and computer microtomography, to analyze the quality of mechanical treatment of the root canal with files of domestic and foreign production.MATERIALS AND METHODS. During the study, single-root and multi-root teeth with different root canal curvature were selected, which were distributed according to the Ni-Ti file system used: group 1 – RM files (RusMed), group 2 – ProTaper Universal (Dentsply Mallifier), group 3 – M-two (VDW).RESULTS. The analysis of scanning electron microscopy of tooth showed that the largest number of open dentine tubules is determined when treating the root canal with instruments of the group 1 (55.4±1.37) and group 3 (60.25±1.59). The centering ability with a curvature of the root canal of 20–25° had no significant differences between the tools used. With a curvature of the root canal of 40–45°, the value of this parameter decreased significantly in all groups of instruments, it was greatest in the groups 1 and 3.CONCLUSION. It was revealed that the best quality of mechanical treatment of the root canal was obtained using RM-files and Mtwo in samples with a channel curvature of up to 25°.

Effect of Spring Machining of Rotary Nickel-Titanium Preparation Systems on Canal Transportation in Curved Root Canals Using Cone Beam Computed Tomography

Effect of Spring Machining of Rotary Nickel-Titanium Preparation Systems on Canal Transportation in Curved Root Canals Using Cone Beam Computed Tomography

Cyclic Fatigue Resistance of Four Heat-Treated Nickel-Titanium Files in Severely Curved Simulated Canals: An In Vitro Study.

Background: Rotary Ni-Ti files are susceptible to sudden intra-canal separation due to cyclic fatigue stress, particularly in curved canals. To increase resistance to cyclic fatigue, new heat-treated files have been introduced. This study aimed to compare the performance of four heat-treated Ni-Ti files in two simulated curved root canals by evaluating the effect of the alloy, rotation speed, and diameter of the files on their resistance to cyclic fatigue. Methods: The Ni-Ti files included in the study were the ProTaper Gold® (Dentsply Sirona) F2, ProTaper Ultimate® (Dentsply Sirona) F2, FQ® (Komet) 25.06, and Blueshaper® (Zarc4Endo) Z4 25.06. Two groups of 30 files were selected for each system and were tested in two simulated canals milled in a specific metal template. One group was tested in a 60° curved canal and the other in a 90° curved canal. Results: In the 60° simulated canal, there were no instrument fractures within the 15 min time limit. In the 90° simulated canal, the Blueshaper Z4 demonstrated a lower resistance to cyclic fatigue, while FQ 25.06 showed statistically higher fatigue resistance based on both the Kruskal-Wallis and Games-Howell tests (p < 0.05). Conclusions: No differences were found between files when tested in a 60° curved canal for up to 15 min. However, in a 90° canal, the FQ® files showed significantly higher resistance to cyclic fatigue, especially compared to the Blueshaper® Z4. The ProTaper Ultimate and ProTaper Gold produced intermediate results, with the ProTaper Ultimate F2 slightly outperforming the ProTaper Gold F2.

Evaluation and Comparison of Dentin Thickness, Centering Ability, Canal Transportation, and Instrumentation Time of Pro AF Baby Gold and Pedoflex Files in Primary Root Canals Using a Cone Beam Computed Tomographic Analysis: An In Vitro Study.

Pediatric rotary systems have the advantage of improved canal centricity and conservative canal preparation with better obturation quality. Pro AF Baby Gold and Pedoflex files are two exclusive pediatric rotary file systems that were introduced in recent times. The aim of the present study is to compare and evaluate the dentine thickness, centering ability, canal transportation, and instrumentation time of Pro AF Baby Gold and Pedoflex files using cone beam computed tomography (CBCT). A total of 40 extracted human primary molar teeth with a minimum 7 mm root length were included in the study and randomly divided into two groups: group I, Pro AF Baby Gold; group II, Pedoflex files. Teeth were imaged preoperatively with CBCT, then root canal preparation was done in both groups with respective files, followed by postoperative CBCT imaging to evaluate the dentin thickness, centering ability, and canal transportation of both groups. Instrumentation time was noted using a stopwatch. There is a statistically significant difference in the instrumentation time; Pedoflex took a shorter time when compared to Pro AF Baby Gold files. Regarding canal transportation, there was no significant difference between the two files, with Pedoflex showing a better value than the other files. Regarding centering ability, there was no significant difference between the two files, with Pro AF Baby Gold having a better value than the other files (p < 0.001). From the findings of our present study, it was found that both systems were able to effectively shape curved root canals in terms of canal transportation and centering ability. Busi S, PJ N, Deoghare A, et al. Evaluation and Comparison of Dentin Thickness, Centering Ability, Canal Transportation, and Instrumentation Time of Pro AF Baby Gold and Pedoflex Files in Primary Root Canals Using a Cone Beam Computed Tomographic Analysis: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(8):892-897.

Comparative analysis of methods for measuring root canal curvature based on periapical radiography: A laboratory study.

To evaluate the agreement between six currently available periapical radiography-based methods for measuring the root canal curvatures in mesial roots of mandibular first molars, assessed by two examiners with different proficiency levels. Non-endodontically treated mesial roots of 41 human mandibular first molars were radiographed using the parallelling technique. Two independent observers (a specialist in endodontics and radiology and a final-year dental student) assessed their root canal curvature using the methodologies described by Schneider (1971, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 32, 271), Weine (1982, Endodontic therapy), Berbert and Nishiyama (1994, Revista Gaúcha de Odontología, 356), Luiten etal. (1995, Journal of Endodontics, 21, 26), Hankins and ElDeeb (1996, Journal of Endodontics, 22, 123) and Pettiette etal. (1999, Journal of Endodontics, 25, 230). Intra- and inter-examiner reliability was assessed using the intraclass correlation coefficient. The differences in curvature angle measured by the different methods were compared using the one-way anova for repeated measures test, followed by Tukey's post hoc analysis. The effect was calculated using the Cohen's d method. To determine the agreement between methods, the Bland-Altman analysis was used. The significance level was set at 5%. Agreement for the observers was excellent (>0.81) for the six methods considered. For the angle comparisons between methods, the maximum differences were for Schneider versus Weine (35.77°) and Luiten versus Hankins (35.14°), whilst the highest percentage of angles with a difference >10° were Weine versus Luiten and Berbert versus Pettiette (90%) and the comparison Weine versus Hankins presented with the lowest frequency (15%). Excellent agreement was found for five comparisons: Weine versus Luiten (0.940), Berbert versus Pettiette (0.917), Weine versus Pettiette (0.907), Luiten versus Pettiette (0.904) and Berbert versus Luiten (0.812). Compared to Schneider's method, the other methods showed a tendency of increasing difference as the angles became more acute. The other methods exhibited linear differences, remaining constant for smaller and larger angles. Reliability was excellent for all methods assessed separately. Maximum differences in curvature angles were found when comparing Schneider versus Weine and Luiten versus Hankins. Excellent agreement was found for Weine versus Luiten, Berbert versus Pettiette, Weine versus Pettiette, Luiten versus Pettiette and Berbert versus Luiten. In the presence of dilacerations, the method by Schneider was less sensitive.

Effect of repetitive up-and-down movements on torque/force generation, surface defects and shaping ability of nickel-titanium rotary instruments: an ex vivo study

BackgroundThe screw-in effect is a tendency of a nickel-titanium (NiTi) rotary endodontic file to be pulled into the canal, which can result in a sudden increase in stress leading to instrument fracture, and over-instrumentation beyond the apex. To reduce screw-in force, repeated up-and-down movements are recommended to distribute flexural stress during instrumentation, especially in curved and constricted canals. However, there is no consensus on the optimal number of repetitions. Therefore, this study aimed to examine how repeated up-and-down movements at the working length affect torque/force generation, surface defects, and canal shaping ability of JIZAI and TruNatomy instruments.MethodsAn original automated root canal instrumentation device was used to prepare canals and to record torque/force changes. The mesial roots of human mandibular molars with approximately 30˚ of canal curvature were selected through geometric matching using micro-computed tomography. The samples were divided into three groups according to the number of up-and-down movements at the working length (1, 3, and 6 times; n = 24 each) and subdivided according to the instruments: JIZAI (#13/0.04 taper, #25/0.04 taper, and #35/0.04 taper) or TruNatomy (#17/0.02 taper, #26/0.04 taper, and #36/0.03 tape) (n = 12 each). The design, surface defects, phase transformation temperatures, nickel-titanium ratios, torque, force, shaping ability, and surface deformation were evaluated. Data were analyzed with the Kruskal-Wallis and Dunn’s tests (α = 0.05).ResultsThe instruments had different designs and phase transformation temperatures. The 3 and 6 up-and-down movements resulted in a smaller upward force compared to 1 movement (p < 0.05). TruNatomy generated significantly less maximum torque, force, and surface wear than JIZAI (p < 0.05). However, TruNatomy exhibited a larger canal deviation (p < 0.05). No statistical differences in shaping ability were detected between different up-and-down movements.ConclusionsUnder laboratory conditions with JIZAI and TruNatomy, a single up-and-down movement at the working length increased the screw-in force of subsequent instruments in severely curved canals in the single-length instrumentation technique. A single up-and-down movement generated more surface defects on the file when using JIZAI. TruNatomy resulted in less stress generation during instrumentation, while JIZAI better maintained the curvature of root canals.

Mineral trioxide aggregate obturation quality with two obturation techniques in severe curved root canals – a micro-CT study

BackgroundThe existence of voids within the mineral trioxide aggregate (MTA) composition is one of the factors that can influence the treatment outcome. The primary objective of this study was to quantitatively assess and compare the MTA orthograde obturation quality in severe curved root canals using two different MTA compaction techniques: manual compaction with K-file, or Auger technique using micro-computed tomography (micro-CT) imaging.MethodsFor this study, 26 mandibular first molar teeth with severely curved mesiobuccal root canals were selected. These samples were randomly divided into two groups. All root canals were instrumented using ProTaper Gold rotary files up to the F3 file at the working length. In one group, OrthoMTA was compacted using a stainless steel K-file, while in the other group, the Auger technique was employed for compaction into the root canals. Once the MTA had completely set, the filled root canals were subjected to scanning using a high-resolution micro-CT scanner. The porosity volume was determined as a percentage in relation to the overal volume of the canal, and the collected data were subjected to analysis using SPSS software, with the significance level set at P < 0.05.ResultsThe two techniques had no significant difference in open, closed, and total mean porosity. In both groups, the mean of open porosity was significantly more than closed porosity.ConclusionsAccording to the results of the present study, neither of these two techniques is preferred to the other, and factors such as working time, etc., can be considered to choose the more appropriate clinical technique.

Evaluation of the shaping ability of different rotary file systems in severely and abruptly curved root canals using cone beam computed tomography

BackgroundWhen selecting an instrument for canal preparation, it is important to consider several parameters that influence the shaping efficiency, including instrument design, metallurgy, and operating motion. This study aimed to evaluate the shaping ability of the ProTaper Next (PTN), WaveOne Gold (WOG), and XP-endo Rise Shaper (XPRS) rotary systems in severely and abruptly curved root canals using cone beam computed tomography (CBCT) and ImageJ software. Materials and MethodsForty-eight mesial root canals of the mandibular first molars were assigned equally to three groups: PTN, WOG, and XPRS. Using ImageJ software, CBCT images were acquired pre- and post-instrumentation to assess dentin removal, remaining dentin thickness (RDT), canal transportation, and centering ratio at the coronal, middle, and apical levels. Statistical analyses were conducted on all numerical data. ResultsAll rotary systems removed significantly more distocoronal dentin in the danger zone (DZ), than the mesiocoronal area. PTN removed significantly more dentin and caused less RDT than XPRS (p < 0.05). However, there were no significant differences between PTN-WOG and WOG-XPRS. In the DZ, the highest percentage of specimens with an RDT < 0.5 mm was observed when using PTN (50%), followed by WOG (31.3%), and XPRS (6.3%). Compared with PTN and WOG, XPRS demonstrated less coronal transportation. Among all rotary systems, there was no significant difference in apical transportation or centering ratio. ConclusionsBased on our observations, all rotary instruments exhibited a tendency to remove dentin in the DZ, but to different degrees. XPRS demonstrated better results in terms of coronal transportation and dentin thickness in the DZ. Comparable centering abilities and minimal apical transportation were demonstrated using all rotary instruments.

Comparison of hand, rotary, reciprocating and self-adjusting files in cleaning mesio-buccal canals of maxillary first molars.

The smear layer removal capability of different instrumentation techniques on the mesio-buccal root canals of maxillary first molars is of interest to dentists. Sixty extracted maxillary first molars with fully developed apices, curved root canals, and curvatures between 30 to 45 degrees were selected. The teeth were divided into four groups (n=15) based on the instrumentation technique used. The samples were analyzed using a thermal field emission scanning electron microscope to assess smear layer removal at the apical, middle, and coronal thirds of the canals. The Wave One file system showed superior performance in smear layer removal across all three regions of the canal compared to hand files, Hyflex CM rotary files and SAF.

Unveiling the fatigue life of NiTi endodontic files: An integrated computational–experimental study

Nickel–titanium (NiTi) rotary files used in root canal treatments experience fatigue and shear damage due to the complex curved geometries and operating conditions encountered within the root canal. This can lead to premature file fracture, causing severe complications. A comprehensive understanding of how different factors contribute to file damage is crucial for improving their functional life. This study investigates the combined effects of root canal curvature radius, file canal curvature, and rotational speed on the fatigue life and failure modes of NiTi endodontic files through an integrated computational and experimental approach. Advanced finite element simulations precisely replicating the dynamic motion of files inside curved canal geometries were conducted. Critical stress/strain values were extracted and incorporated into empirical fatigue models to predict the functional life of endodontic files. Extensive experiments with files rotated inside artificial curved canals at various canal curvatures and speeds provided validation. Increasing the canal curvature beyond 60∘ and shorter curvature radii below 5 mm dramatically reduced the functional life of the endodontic file, especially at rotational speeds over 360 rpm. The Coffin–Manson fatigue model based on strain amplitude showed the closest agreement with experiments. Shear stresses dominated damage at low canal curvatures, while the combined shear-fatigue loading effects were prominent at higher canal curvatures. This conclusive study elucidates how operational parameters like canal curvature radii, canal curvature, and rotational speed synergistically influence the fatigue damage processes in NiTi files. The findings offer valuable guidelines to optimize these factors, significantly extending the functional life of endodontic files and reducing the risk of intra-operative failures. The validated computational approach provides a powerful tool for virtual testing and estimation of the functional life of the new file designs before manufacturing.

Does Root Canal Shaping Effect the Accuracy of Electronic Apex Locators in Curved and Straight Root Canals?

Objective: To assess the influence of root canal preparation (RCP) on the precision of electronic apex locators (EALs) in both straight and curved root canals. Methods: The experimental setup included forty-two extracted human mandibular molars featuring both straight distal canals (0-10 degrees) and curved mesial root canals (30-50 degrees). Initial working length (AWL1) measurements were conducted under a stereomicroscope at X15 magnification prior to root canal preparation (RCP). Subsequently, electronic working length (EWL1) was determined using two different electronic apex locators (EALs) – Propex-Pixi and EndoRadar. RCP was carried out with ProTaper Ultimate F1, F2 files in mesial canals, and F1, F2, F3 files in distal straight root canals. The RCP procedure involved the implementation of a standard irrigation protocol along with the use of a sonic device for activation. Following RCP, measurements were repeated under a stereomicroscope and documented as AWL2. EWL measurements were also repeated and recorded as EWL2 after the preparation. The variation was calculated by subtracting AWL from EWL for each tooth (EWL1-AWL1 and EWL2-AWL2). Statistical analysis employed Paired Sample t-test and Wilcoxon tests. Results: There was no statistically significant difference observed in the accuracy of Propex-Pixi and EndoRadar Pro before and after root canal preparation for both straight and curved canals. Conclusion: Root canal preparation did not alter the accuracy of the electronic apex locators (EALs) used in this study, whether applied to curved or straight root canals.

Assessment of Mesiobuccal Root Canal Curvature in Maxillary Molars of Egyptian Population: A Standardized CBCT-Based Radiographic Protocol

Assessment of Mesiobuccal Root Canal Curvature in Maxillary Molars of Egyptian Population: A Standardized CBCT-Based Radiographic Protocol

Quality of Root Canal Filling in Curved Canals Utilizing Warm Vertical Compaction and Two Different Single Cone Techniques: A Three-Dimensional Micro-Computed Tomography Study.

Successful endodontic treatment depends on three-dimensional (3D) root canal filling to prevent the leakage of residual bacteria. Different obturation techniques with different sealers should be compared by employing advanced assessment tools. This study compared the obturation quality of warm vertical compaction (WVC) and two different single-cone (SC) techniques using micro-computed tomography (micro-CT). Thirty-three extracted maxillary molars with mesial root canal curvature of 20‒40º were prepared in vitro with One-Curve files and randomly assigned to three groups (n=11) for root canal obturation with WVC, SC technique with AH Plus sealer (SC-AH), or SC technique with SureSeal bioceramic (BC) sealer (SC-Su). The root canals underwent micro-CT examinations before and after obturation to determine the volume percentages (VPs) of voids and gaps at different distances from the apex (coronal, middle, and apical thirds). Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. The highest VP of voids and gaps was recorded in the SC-Su group, with no significant difference from other groups (p> 0.05). There were significant differences in VP of gaps at different distances from the apex (p<0.05). The VPs of gaps in the apical third of all the samples were significantly higher than in the coronal and middle thirds. However, the difference in VP of voids was not significant at different distances from the apex (p>0.05). None of the tested techniques could provide a void-free and gap-free filling. The apical third of the canals showed the highest VP of gaps in all obturation techniques.

Comparative Analysis of Cyclic Fatigue Resistance of NeoEndo Flex Vs Protaper Gold Rotary Files: An In-Vitro Study

Background: During the endodontic process, cleaning and shaping are essential steps. The fracture of nickel-titanium (NiTi) tools is a procedural issue that significantly impedes therapy in normal endodontic therapy. Efficient and reliable endodontic therapy requires rotary NiTi files that demonstrate superior cyclic fatigue resistance to prevent file separation within the canal. This study aimed to investigate the in-vitro cyclic fatigue resistance of two commonly used rotary NiTi files: NeoEndo Flex file and ProTaper Gold file. Methods: The cyclic fatigue tests were carried out by determining the lifespan of each file type in a controlled environment mimicking a curved root canal. A total of 30 files (15 NeoEndo Flex and 15 ProTaper Gold) were subjected to continuous rotation until fracture occurred. The numbers of cycles until failure (NCF) were recorded for statistical comparison. Results: The ProTaper Gold files showed significantly higher NCF, indicative of stronger cyclic fatigue resistance when compared to NeoEndo Flex files (p &lt; 0.05). The variance in fatigue resistance is attributable, in part, to differences in alloy composition and proprietary heat treatment processes. Conclusion: ProTaper Gold rotary NiTi files exhibited enhanced cyclic fatigue resistance in comparison to NeoEndo Flex, suggesting that they may be the preferred choice for clinical procedures where greater stresses are anticipated on the file. However, clinicians should balance file strength with other clinical factors when choosing the appropriate file for endodontic treatment.

Micro-computed tomography analysis of shaping ability of nickel-titanium instruments activated by continuous rotation or adaptive motion.

This study assessed the ability of Twisted File Adaptive (TFA), TruNatomy (TRN) and VDW.Rotate (VR) instruments activated by continuous rotation (CR) and adaptive motion (AM) to shape curved root canals. Thirty mandibular molars with two separate mesial canals 20°-40° curved were collected and scanned using micro-computed tomography (μCT). The canals were then randomly assigned into six groups (n = 10): TRN, VR or TFA instruments activated by CR or AM. TRN groups 17.02, 20.04 and 26.04; VR groups 15.04, 20.05 and 25.06; TFA groups were shaped consecutively using 15K-file, 20.04 and 25.06. After they were shaped, the canals were scanned again. The volume of removed dentin, canal transportation and centring ratio were calculated μCT images. All data were analysed using the Kruskal-Wallis test or one-way analysis of variance (p < 0.05). With both kinematics, the TRN instrument removed the least amount of dentin, the VR-CR and the TFA-AM removed the most (p < 0.05). The transportation and centring ratios among all groups were similar (p > 0.05). The volume of dentin removed, the diameter or design features of the instruments and different kinematics did not affect the centring ratio and the amount of transportation and remained within safe limits. All three instruments activated by either kinematics were found to have similar effectiveness in shaping curved root canals.

Assessment of Biomechanical Preparation Influence on Various Root Canal Curvatures.

To determine the influence of biomechanical preparation on various parameters of root canal curvature. A total of 72 tooth roots with moderate (10-25°) and severe canal curvature (26-75°) were selected and embedded in autopolymerizing acrylic resin for which cone-beam computed tomography (CBCT) image analysis was performed. Schneider angle, canal access angle (CAA), and the radius of curvature were determined preoperatively using auto-computer-aided design (CAD) 2021 software. Protaper gold rotary nickel-titanium (Ni-Ti) files were used to prepare the root canals. All angular and linear values were measured in auto-CAD and compared using postoperative CBCT pictures. The difference in pre- and postoperative values was assessed using paired samples t-test and independent samples t-test. There was a statistically significant difference between the Schneider angle (p = 0.002), (p < 0.001), CAA (p < 0.001), (p = 0.001), and radius of curvature (p = 0.01), (p = 0.001) pre- and postoperatively in both moderate and severe canal curvature groups, respectively. This difference was greater in the severe curvature group (p-value = 0.027) than in the group exhibiting moderate curvature. Among the parameters tested, Schneider angle has shown maximum difference pre- and post before and after mathematical processing (BMP) compared to other parameters. This approach is a new and objective way of measuring root canal geometric changes. The current findings suggest that the Schneider angle, CAA, and the radius of curvature can be used as parameters to evaluate the changes in canal geometry following biomechanical preparation. Nekkanti H, Enuganti S, Avula JSS, et al. Assessment of Biomechanical Preparation Influence on Various Root Canal Curvatures. Int J Clin Pediatr Dent 2024;17(2):130-135.

Deviation of Root Canal Curvature Using Three Types of Rotary Instruments: An In Vitro Study

One of the essential requirements for a successful endodontic treatment is efficient cleaning and shaping. Since its introduction, the nickel-titanium rotary system has gained popularity due to its elasticity and suppleness in the creation of curved root canals. To assess the deviation in root canal curvature in severely curved root canals following three different rotary file system preparations. Thirty-six human permanent mandibular first molars were chosen and stored in regular saline after being newly extracted with the curve mesial root. To standardize length at 13 mm, the mesial roots were separated from the tooth and the crown was removed. The three groups of teeth were A, B, and C. Groups A, B, and C were equipped with rotary variable taper instruments, reciprocating variable taper instruments, and rotary constant taper control memory instruments, respectively, in their mesio buccal canals. The instruments were never pressed apically; instead, they were employed in the canal with a constant, gentle passive movement. With frequent and copious irrigation using 5.25% sodium hypochlorite solution and 17% ethylene diamine tetra acetic acid, all canals were shaped and cleansed. To assess the curvature deviation, periapical radiographs were taken both before and after preparation. By using the Schneider method to measure the pre- and post-instrument canal curvatures, the deviation was found. The Wilcoxon test was employed for numerous pairwise comparisons across distinct groups, and the Kruskal-Wallis test was used to conduct statistical analysis among three groups. The p-value of less than 0.05 was deemed statistically significant. Compared to groups A and B, group C had the least variation of canal curvature. The current study concludes that a 4% rotating constant taper control memory instrument works better than a rotary variable taper instrument or a reciprocating variable taper instrument for shaping a curved canal.

Endodontic treatment of severely curved root canals – A case series

Background: It is not uncommon for a dentist to encounter endodontic cases of severely curved root canals. Performing endodontic treatment on severely curved root canals can be a daunting task due to the notable risk of creating an iatrogenic error including ledge, perforation, or even instrument separation. Therefore, radiograph image analysis, proper endodontic treatment planning, selection of appropriate instruments and technique is essential to ensure success in endodontic treatment of severely curved root canals. Purpose: This case series aims to elaborate the instruments and technique to safely negotiate, clean, shape, and seal root canals with severe curvature. Cases: Three patients came to Universitas Airlangga Dental Hospital due to a severe toothache. After anamnesis and examination, diagnosis was established, and endodontic treatment was deemed necessary. During radiographic image analysis, it is visible that the root canal had a severe curvature. Case Managements: Access opening was performed to allow a straight-line access, orifices were preflared, root canals were negotiated, and glide path was established. Then, shaping, cleaning, and sealing can be performed conveniently until the root canal terminus. Subsequently, coronal restoration was fabricated to restore function and esthetics. Conclusion: With proper knowledge, case analysis, appropriate instruments and techniques, severely curved root canals can be safely and predictably negotiated, cleaned, shaped, and sealed.