Root Canals Of Molars Research Articles

Evaluation of Root Canal Morphology of the Maxillary Permanent First Molar among Iraqi Population: A Cone Beam Computed Tomography Study (Retrospective Study)

Purpose: Endodontic success mainly depends on the complete root canal system debridement, both mechanically and chemically. The maxillary first molar possesses one of the most complex root canal anatomy. The purpose of this study was to map the maxillary first molar's root canal anatomy and its variations. Cone Beam Computed Tomography (CBCT) was used to determine the prevalence of the Second Mesiobuccal Canal (MB2) and its possible relation to the gender of the patient in the Iraqi population. Materials and Methods: Images from documented archives of CBCT scans for 415 patients who had maxillofacial diagnosis or root canal treatment were used in this study. Totally 656 maxillary first molars (336 females and 320 males) were included. The root canal configuration, frequency of MB2, and its two-sided symmetry were observed. The (chi-square test) was used to calculate the gender correlation. The P-value of less than 0.05 (p < 0.05) was considered significant. Results: In 61.1% of the cases, the MB2 canal was discovered with high bilateral symmetry (73.6%). Genders did not show any statistically significant differences. Conclusion: The existence of MB2 canal in the maxillary first molars is high and approximately more than half of the cases. No relation was found between the existence of the MB2 canal and the gender of the patient. CBCT is a clinically efficient method for the diagnosis and improvement of root canal therapy.

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.

The Impact of Minimum Invasive Access Cavity Design on the Quality of Instrumentation of Root Canals of Maxillary Molars Using Cone-Beam Computed Tomography: An in Vitro Study.

Aim Minimally invasive dentistry has been facilitated by advances in instruments and restorative materials. This study aims to compare the change in the shaping ability of the RECIPROC blue rotary system in both traditional and conservative access cavities, using cone beam computed tomography (CBCT). Material and methods Sixty root canals of 20 artificial maxillary molars were assigned into two groups (n=30 root canals) according to the access cavity design used: Group I: traditional access cavity (TAC) and Group II: conservative access cavity (CAC). CBCT scans of samples were made before and after root canal preparation using the RECIPROC blue rotary system. The shaping parameters are evaluated in root canal transportation and the centering ability. Three CBCT sections per tooth were analyzed at 3, 6, and 9 mm from the apex to assess the canal transportation and centering ability at three levels, apical, middle, and coronal thirds. Data were analyzed using the GraphPad Prism (GraphPad Software, San Diego, CA). Results The results of this study showed a significant difference in transportation within the coronal and middle thirds. However, in apical thirds, there were no significant differences. Both groups observed a significant difference in the centering ability in the coronal third. Conclusion Within the limitations of this study, CAC can be recommended with caution as an alternative access to TAC.

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.

Postoperative Pain Comparison: Manual K-Files vs Pedoflex Rotary Files in Primary Molar Root Canals

This study evaluated postoperative pain in pediatric patients after root canal treatment with two file systems: Manual K-files and Pedoflex Rotary files. Sixty children, aged 6-10, were randomized into two groups of 30. Pain was assessed using a Visual Analog Scale (VAS) at 6, 12, 24, and 48 hours post-treatment. Results showed significantly lower pain levels in the Pedoflex Rotary file group at all time points (mean VAS at 6 hours: 2.4 vs. 3.8; at 12 hours: 1.8 vs. 3.2; at 24 hours: 1.2 vs. 2.5; at 48 hours: 0.6 vs. 1.8). Pedoflex Rotary files provide a more comfortable postoperative experience.

Frequency of C-Shaped Root Canals in Permanent Mandibular Second Molars in a Sample of Pakistani Population using Cone Beam Computed Tomography

Frequency of C-Shaped Root Canals in Permanent Mandibular Second Molars in a Sample of Pakistani Population using Cone Beam Computed Tomography

Root anatomy and canal configuration of human permanent maxillary third molar - systematic review.

Knowledge of the root canals configuration is essential for the success of endodontic treatment. The main aim of the systematic review is to determine the number of roots and the number of root canals in maxillary third molars, in addition, where possible, to determine the Vertucci classification. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guidelines. The study protocol was registered and approved on the International Prospective Register of Systematic Reviews PROSPERO (Reg. No: CRD42022366444) before the start of the study. Twelve studies were included in the analysis, differing in sample origin and methodology. The combined studies were analyzed based on the number of roots, number of canals, and root canal configurations, and the findings were compared with those of other international studies. Analyzing the available research results regarding the root anatomy and canal configuration of the third maxillary molar, the most commonly maxillary third molars had 3 roots (59.00%). Single-rooted teeth (24.20%) or double-rooted teeth (13.80%) were less common. In addition, it was observed that maxillary third molars typically possessed three root canals (47.28%) and the MB (mesiobuccal), DB (distobuccal), and P (palatal) canals most often showed Vertucci Type I (59.53%, 95.83% and 98.61%, respectively) in three-rooted form. Due to the small number of available studies, it is necessary to conduct further analyses taking into account demographic and ethnic differences that may affect the anatomical and morphological structure of the teeth.

Biomechanical impact of different isthmus positions in mandibular first molar root canals: a finite element analysis.

This study used image-based finite element analysis (FEA) to assess the biomechanical changes in mandibular first molars resulting from alterations in the position of the root canal isthmus. A healthy mandibular first molar, characterized by two intact root canals and a cavity-free surface, was selected as the subject. A three-dimensional model for the molar was established using scanned images of the patient's mandibular teeth. Subsequently, four distinct finite element models were created, each representing varied root canal morphologies: non-isthmus (Group A), isthmus located at the upper 1/3 of the root (Group B), middle 1/3 of the root (Group C), and lower 1/3 of the root (Group D). A static load of 200 N was applied along the tooth's longitudinal axis on the occlusal surface to simulate regular chewing forces. The biomechanical assessment was conducted regarding the mechanical stress profile within the root dentin. The equivalent stress (Von Mises stress) was used to assess the biomechanical features of mandibular teeth under mechanical loading. In Group A (without an isthmus), the maximum stress was 22.2MPa, while experimental groups with an isthmus exhibited higher stresses, reaching up to 29.4MPa. All maximum stresses were concentrated near the apical foramen. The presence of the isthmus modified the stress distribution in the dentin wall of the tooth canal. Notably, dentin stresses at specific locations demonstrated differences: at 8mm from the root tip, Group B: 13.6MPa vs. Group A: 11.4MPa; at 3mm from the root tip, Group C: 14.2MPa vs. Group A: 4.5MPa; at 1mm from the root tip, Group D: 25.1MPa vs. Group A: 10.3MPa. The maximum stress in the root canal dentin within the isthmus region was located either at the top or bottom of the isthmus. A root canal isthmus modifies the stress profile within the dentin. The maximum stress occurs near the apical foramen and significantly increases when the isthmus is located closer to the apical foramina.

Elimination of E. faecalis with NaOCl versus chlorhexidine gluconate from primary molar root canal systems: an ex vivo model study

ObjectivesThis ex vivo human study aimed to evaluate the efficacy of NaOCl and chlorhexidine gluconate (CHG) irrigations in eliminating Enterococcus faecalis from the RCS of primary molars.Materials and methodsDisinfected extracted primary molars were inoculated with E. faecalis for 24 h. Then, the RCS samples were then irrigated with either 2.5% NaOCl, 0.2% and 2% CHG, or sham saline. The samples were collected immediately after irrigation; and 24 h later, the bacterial viability and counts were measured using blood agar and qRT-PCR, respectively. Histological sections were used to measure E. faecalis penetration and viability in dentin tubules using fluorescence microscopy.ResultsThe recovery of viable E. faecalis after the irrigation of the primary molars showed more significant bactericidal effects of NaOCl and 0.2% and 2% CHG than of saline. Immediately after the irrigation, the NaOCl group showed the greatest reduction in E. faecalis; and 24 h later, all the groups had lower viable E. faecalis than the saline control. The bacterial penetration was also lowest in the NaOCl group, although there was no difference in bacterial viability in the tubules between the groups.ConclusionIn primary teeth, NaOCl and CHG showed similar degrees of bacterial elimination efficacy in terms of E.faecalis.Clinical relevanceWithin the limitations of this study, NaOCl and CHG have the similar ability to perform endodontic irrigation of primary ex vivo teeth regarding the elimination of E.faecalis, but NaOCl penetrates dentin tubules better.

Molar root canal treatment performed by undergraduate dental students; an observational study of procedural errors and student perception

BackgroundMolar root canal treatment (RCT) is challenging and requires training and specific skills. Rotary instrumentation (RI) reduces the time needed for instrumentation but may increase the risk of certain procedural errors. The aims of this study were to evaluate the quality of molar RCTs provided by undergraduate students, to compare the prevalence of procedural errors following manual and RI, and to assess the students’ self-perceived confidence to perform molar RCT without supervision and their preference for either manual or RI.MethodsMolar RCTs performed by the final year students were evaluated radiographically according to predefined criteria (Appendix 1). The procedural errors, treatment details, and the students’ self-perceived confidence to perform molar RCT and their preference for either manual or RI were recorded. Descriptive statistics were performed, and the Chi-squared test was used to detect any statistically significant differences.Results60.4% of RCTs were insufficient. RI resulted in more sufficient treatments compared with MI (49% vs. 30.3% respectively. X2: 7.39, p = 0.007), required fewer visits to complete (2.9 vs. 4.6 respectively. X2: 67.23, p < 0.001) and was the preferred technique by 93.1% of students. The most common procedural errors were underextension of the root canal obturation (48.4%), insufficient obturation (45.5%), and improper coronal seal (35.2%) without a significant difference between the two techniques. 26.4% of the participating students reported that they did not feel confident to perform molar RCT without supervision.ConclusionThe quality of molar RCT provided by UG students was generally insufficient. RI partially improved the technical quality of RCT compared with MI. UG students need further endodontic training and experience before they can safely and confidently practise molar RCT.

Maxillary second molar with morphologic variations in number of roots &amp; canals: Literature review &amp; report of two cases

The root canal and root morphologies of maxillary second molars might vary. This article details the endodontic treatment of two cases involving unusual root canal morphology in a maxillary second molar. The first case involved a single root and a single canal, whereas the second case had a single root with two separate canals. A literature review was conducted to clarify the prevalence of anatomical changes in the number of roots and canals in the maxillary second molar. The utilisation of a dental operating microscope facilitated the detection of the canal orifices in both cases. The objective of this study is to increase the knowledge of clinicians regarding the atypical structure of root canals by examining the complex differences found in maxillary second molars.

Influence of access cavity design on root canal instrumentation efficacy in molars - An in vitro study.

Several designs of access cavity have been evolved in the recent past with the concept of minimal tooth tissue removal which would improve the root canal treated teeth fracture resistance. To investigate the effect of conservative design access cavity during the instrumentation of maxillary molar root canals. Eighty noncarious maxillary molars were assigned to the traditional and conservative access groups (n = 40 each). After designated access preparations, the teeth were immersed in Lugols's solution for staining the pulp tissue. Root canal instrumentation was performed with TruNatomy file system. Pre- and postinstrumentation nano-computed tomography (CT) images were taken and reconstructed using CT-An software. Root canals volumetric analysis was done with CT-Vol software. The analysis of the data was dealt with Shapiro-Wilk test and independent t-test. The volume of pulp canal space before and after instrumentation changed significantly between the traditional and conservative access design groups, according to an independent t-test. In comparison, the mean volume of dentin removed was much larger in the TAC group (P = 0.0016). The independent t-test manifests difference significantly between traditional endodontic access cavity (TAC) and conservative access cavity (CAC) with percentage of unprepared canal walls. The mean percentage of unprepared area was significantly lesser in TAC group as compared to CAC group (P = 0.0022). The volume of dentin removed was greater in TAC than with the CAC design. The amount of untouched canal wall area was significantly higher in conservative access design than with the traditional access design group.

Microcomputed tomographic evaluation of 6 NiTi files on the pericervical dentin and the smallest dentin thickness zones in mesial root canals of mandibular molars: an in vitro study.

The aim of this study was to evaluate six files on the pericervical dentin (PCD) and the smallest dentin thickness zones (SDTZ) in mesial root canals of mandibular molars. Sixty mandibular molars with two mesial canals and Vertucci configuration were aleatory allocated in 6 experimental groups of 10 molars and 20 root canals. Specimens were scanned before instrumentation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WaveOne Gold (WG), group 2 with Reciproc Blue (RB), group 3 with TRUShape (TS), group 4 with XP-endo Shaper (XP), group 5 with iRace (IR), and group 6 with TruNatomy (TN). After instrumentation, the molars were scanned again and the images recorded were reconstructed with the NRecon v.1.7 (Bruker micro-CT) and analyzed with CTAn v.1.20.8 software (Bruker micro-CT) quantifying the changes produced in the surface, volume, structure thickness, SMI, and centroids at the Pericervical Dentin area of the root canals (PCD) located from the root canal orifices at the floor of the pulp chamber to 4 mm in the apical direction, and the changes in the Smallest Dentin Thickness Zones (SDTZ) located (from the furcation to 4 mm and 7 mm in the apical direction. The data obtained were compared using Wilcoxon and ANOVA with a 5% significance level. XP and TN were similar in all the parameters (P >.05) at the PCD, but TN showed significant differences from WG, RB, TS, and IR (P <.05), while XP showed significant differences from WG (P <.05) in volume, surface, and structure thickness. Regarding the changes in the SDTZ, the amount of dentin removed was similar between the groups in both canals at the middle 1/3, at the cervical 1/3 for MB canals, and in ML canals for RB, TS, XP, IR, and TN (P>.05). The action of WG was significantly different from that of XP and TN in the cervical 1/3 of the ML canal (P <.05). XP and TN rotatory files with small taper and volume maintained better with minor changes at the PCD and SDTZ, while WG reciprocation file produced the largest change. All the files were maintained centered at the PCD, and their performances were safe with a minimal thickness higher 0.5 mm at the SDTZ, and without risk of perforation. No clinical trials were indicated in this study. The choice of endodontic files is a relevant factor in the conservative performance of root canal treatments.

Evaluation of Presence of Enterococcus faecalis in Root Canals of Deciduous Molars with Necrotic Pulp by Agar Culture and Polymerase Chain Reaction.

To assess the presence of Enterococcus faecalis in root canals of deciduous molars with necrotic pulp by agar culture and polymerase chain reaction (PCR) assay. This is an experimental study, where a total of 120 endodontic samples were taken from deciduous molars with necrotic pulps. The presence of Enterococcus faecalis was assessed by culture, using Enterococcus confirmatory agar, and by PCR assay. Statistical analysis of the results was performed using McNemar's test. The presence of Enterococcus faecalis was detected in 20 samples (16.67% of total) by microbial culture and in 45 samples (37.5% of total) by PCR assay, with a statistically significant difference between the two methods (p < 0.001). Microbial culture and PCR both detect Enterococcus faecalis, with the latter detecting an additional 25 positive samples. In this study, PCR assay was significantly more sensitive than agar culture method in detecting the presence of Enterococcus faecalis in root canals of deciduous molars with necrotic pulp, that is, 37.5% of all samples. Importance of presence of Enterococcus faecalis in necrotic pulps of deciduous teeth, as it is primarily responsible for failure of endodontic treatment, thus helping clinicians to advocate the use of local drug delivery in primary teeth endodontics and also aids clinicians in choosing the most effective intracanal medication. Nalawade TM, Bhat KG, Kale AD, et al. Evaluation of Presence of Enterococcus faecalis in Root Canals of Deciduous Molars with Necrotic Pulp by Agar Culture and Polymerase Chain Reaction. Int J Clin Pediatr Dent 2023;16(6):816-819.

Distolingual root prevalence in mandibular first molar and complex root canal morphology in incisors: a CBCT analysis in Indian population

Cone-beam computed tomography was used to understand the possible correlation between the prevalence of distolingual root (DLR) in permanent mandibular first molars (MFMs) and the associated complicated mandibular incisor’s root canal morphology (MIs) in an Indian population. A total of 400 scans were evaluated for MFMs and MIs. The prevalence of DLRs and root canal anatomy of MIs were assessed based on Vertucci’s classification, and then the sample were grouped according to age, sex and side. Statistical analysis was used to evaluate the possible correlation between the presence of DLRs in the first molar and root canal morphology of incisors. Chi square test was used to evaluate the correlation between the root canal configurations of MIs with the existence of DLRs in MFMs. There was no statistically significant difference between sexes or ages for the prevalence of DLRs in the first molars (p > 0.05), which was 6.62%, with the right side having a greater frequency of DLRs (7.8%) than the left (5.5%). Vertucci Type I canal configuration was most common for the mandibular central (66.75%) and lateral incisors (58.62%). Vertucci Type III was the most common complicated canal morphology, followed by Types V, II, and IV for MIs, with no statistically significant difference in the studied sample's age and sex. (p < 0.05). No association was observed between the presence of DLRs in first molars and complicated root canal configurations in MIs. Taken together, the possibility of complicated root canal configuration in MIs was lesser in the presence of DLRs in MFMs among the Indian population.

Micro-computed tomography (micro-CT) evaluation of root canal morphology in immature maxillary third molars.

The endodontic treatment of immature permanent teeth with necrotic pulp is a significant clinical challenge. The success of regenerative endodontic procedure is highly dependent on disinfection of the root canal and an accurate anatomical knowledge of the root canal. The aim of this study was to use micro-computed tomography (micro-CT) analysis to investigate the configuration of root canals in the upper permanent third maxillary molars with incomplete root development in their coronal, apical and middle third portions. Thirty immature third permanent maxillary molars were scanned using a micro-CT system. Then, we measured the diameters and areas of the root canal in the coronal, middle and apical third of the roots. The ratio between the long and short diameter of each root canal was then calculated and the canals were divided into several groups: round, oval, long oval, flat and irregular. The round configuration was not observed in the distobuccal and mesiobuccal roots in any of their anatomical regions. Oval and long oval canals predominated in the distobuccal root. The greatest variations were observed in the mesiobuccal root, with the ribbon-shaped canal predominating in the middle region and an irregular shape in the apical region. In the coronal region of the palatal canal, the round configuration predominated; in the middle third, we observed an almost equivalent distribution between round and oval configurations; apically, the oval shape predominated. In conclusion, we observed significant complexity and variation in the morphology and configuration of root canals in immature permanent molars, thus generating additional obstacles for the success of regenerative endodontics.

Natural canal deviation and dentin thickness of mesial root canals of mandibular first molars assessed by microcomputed tomography.

The aim of this study was to assess the centralization and dentin thickness of mesial root canals of the first mandibular molars by microcomputed tomography (micro-CT). Material and methods: Ninety-nine mandibular molars of Vertucci's type IV canals were scanned by micro-CT. The mesiodistal deviation and centroid were assessed, in both mesiobuccal (MB) and mesiolingual (ML) canals, for the apical 4mm and the full canal length. Results: The dentin thickness was similar for both MB and ML canals. The narrowest thickness was in the distal wall of an MB canal (0.07mm), while the widest was found in the mesial wall of an MB canal (2.46mm). In centroid analysis, both the MB and ML canals exhibited deviations when compared to the root centroid, along the full canal length and the apical 4mm. For the MB canal, the mean deviation was 0.83mm (0.02 mm-2.30 mm) for the full canal and 0.18mm (0.01 mm-1.01 mm) for apical 4mm. Similarly, for the ML canal, the mean deviation measured 0.83 mm (0.05mm-3.99mm) for the full canal and 0.21 mm (0.01mm-1.01mm) for the apical 4 mm. Overall, deviations were observed towards the mesial of the roots, with 69% for MB and 57% for ML canals for the full canal, and 51% for MB canals within the 4 mm. The exception was the ML canal, which exhibited a higher deviation towards distal in the apical 4mm, accounting for 52% of cases. The dentin thickness was consistent between the mesial canals of mandibular molars. However, there is no centrality of mesial canals in their roots, with frequent deviation to mesial.

Residual dentin thickness of root canal transportation by various metallurgical rotary systems: An in vitro study

Introduction: Numerous nickel–titanium (NiTi) rotary systems have been released on the market with noncutting tips, various cross sections, and production techniques. This research was carried out to assess the quantity of remaining dentin thickness of mandibular first molar root canal at 3, 6, and 9 mm far from the anatomic peak that prepared through contemporary rotating systems with different metallurgical properties with a cone-beam computed tomography (CBCT). Materials and Methods: In this investigation, 45 human mandibular first molars that had been extracted were employed. Teeth were accordingly divided into three main groups through the NiTi rotary system that was utilized in canal instrumentation (15 teeth each), such that all ranges of curvatures were equally represented in each group – Group A: EdgeFile X3 rotating system, Group B: ProTaper Next (PTN) rotating system, and Group C: ProTaper (PT) rotating system. The samples were scanned before and after instrumentation using CBCT, and by deducing the instrumented canals from the uninstrumented counterpart, the remaining dentin thickness for each root canal is calculated at three levels of each root (3, 6, and 9 mm away from the root end). Data were statistically analyzed. Results: A significantly higher mean value was scored in PT, followed by PTN, and the lowest value was found in X3 of canal transportation at the level of 3 mm (P &lt; 0.001), whereas at the 6- and 9-mm levels, there was no substantial difference statistically through the levels. Conclusion: The EdgeFile X3 showed the lowest canal transportation at a 3-mm level from the apex in comparison to the other tested files.

Micro-CT Assessment of Filling Removal Effectiveness in the Apical Third of Curved Canals with Different Types of Anatomy.

The aim of this study was to assess the effectiveness of filling removal material from the apical third of curved mesial root canals of mandibular molars. Reciprocating instrumentation followed by additional rotary instrumentation with instruments made of alloys with different heat treatments was evaluated. Thirty-six mesial roots of mandibular molars were divided into two groups: Group Class IV consisted of 16 roots with two independent canals, and Group Class II consisted of 20 roots with two canals that merged into one at their apical level. Each of these two groups were further divided into two subgroups, according to the additional rotary instrument used after the reciprocating instrumentation: Group RH and Group RM for Hyflex and Mtwo, respectively. After each procedural step, the roots were scanned by micro-tomography. After each step of filling removal, the Wilcoxon matched pair test and the Mann-Whitney test were used for the evaluation between groups. The significance level adopted was 5%. Significant differences were observed between groups with different Class II and Class IV anatomies, regarding filling removal after Reciproc (P<0.05). After the use of an additional rotary instrumentation, no differences were observed between the two groups (P>0.05). In the apical third of mesial roots of mandibular molars with Class II anatomy, an additional rotary instrumentation was shown to be necessary for improving the removal of filling material after using the single-file reciprocating instrumentation technique.

Antibacterial ability of different activated irrigation after root canal preparation: intratubular analyses.

This study assessed the intratubular antibacterial ability of different activated irrigations after chemical mechanical preparation. Seventy-two palatal root canals of upper molars were infected with Enterococcus faecalis for 4 weeks, and then initial bacterial collection from the main root canal was performed. The root canals were prepared by using a WaveOne Gold large (45/.05) and distributed into 6 groups according to the activation of the final irrigation: ultrasonic activation (UA), XP-Endo Finisher (25/.00), XP Clean (25/.02), EasyClean (25/.04) in reciprocating motion and continuous rotary motion (ECRot), and conventional irrigation. After final irrigation, another bacterial collection from the main root canal was performed, and the root was sectioned transversely in three-thirds and stained for analysis by confocal laser microscopy. Intratubular bacteria were collected through dentin powder and plated for bacterial viability analysis. Intergroup and intragroup comparisons were performed by using analysis of variance and repeated measures analysis of variance, respectively, both at 5% significance. ECRot had higher antibacterial ability than UA (p<0.05), and both were superior to the other groups (p<0.05) in both methodologies. It can be concluded that activation of final irrigation enhances the disinfection of the root canal system, and activators have different efficacies.