Mesiobuccal Canals Research Articles

The prevalence, configuration, and prediction of second mesiobuccal canals in maxillary second molars in West Bengal population – A cone-beam computed tomography study

Abstract Objective: This study’s objective is to analyze the prevalence as well as the configuration of second mesiobuccal (MB2) in maxillary 2nd molars and predict its existence based on mesiobuccal-palatal (MB-P) distance, MB-P/distobuccal-palatal (DB-P) distance ratio and mesiobuccal, distobuccal, and palatal orifice (MDP) angle with the help of cone-beam computed tomography. Materials and Methods: The presence and absence of MB2 are noted down in 300 maxillary 2nd molars. Canal configuration was observed from the orifice to the apex in the mesiobuccal root. Interorifice distances of MB-DB, MB-P, and DB-P were measured. MB-P and DB-P ratios have been computed. MDP angle was also measured. Then, MB2 existence and the above factors are correlated. Results: The prevalence of MB2 is increased as the values increase in MB-P distance (>5.25 mm), MB-P and DB-P ratio (>1.25), and MDP angle (>95°). Out of 150 MB2 teeth, Vertucci type 2, 4, and 8 Configurations are seen in 103 (68.6%), 46 (30.6%), and 1 (0.67%), respectively. Conclusions: This positive correlation between MB2 presence and these three factors helps clinicians to identify MB2 canals effectively.

Comparative evaluation of different endodontic access cavity designs on canal transportation and centering ability using bondent platinum file system on mandibular molar – An in vitro cone-beam computed tomography study

ABSTRACT Aim: This study aimed to compare the effects of different endodontic access cavity designs on canal transportation (CT) and centering ability (CA) using the bondent platinum file system on mandibular molars, utilizing cone-beam computed tomography (CBCT). Methodology: Thirty extracted human permanent mandibular molars which fulfilled the inclusion criteria were divided into three groups, Group 1 (TEC): Traditional endodontic access cavity (control group), Group 2 (CEC): Conservative endodontic access cavity, and Group 3 (TrEC): Truss endodontic access cavity. The teeth were scanned using CBCT initially followed by random allocation into three groups. Root canals were prepared using Bondent platinum file system in mesiobuccal and mesiolingual canals using #25.06 file and in distal canal #30.06 file. Postpreparation, CBCT scans to assess CT and CA at 3 mm, 5 mm, and 7 mm from the apex. Data analysis was performed using a one-way analysis of variance and Tukey’s post hoc test. Results: Significant differences (P < 0.01) in mean CT and CA were observed between Group 1 (TEC) and Groups 2 (CEC) and 3 (TrEC). Dentin removal was highest at 3 mm, followed by 5 mm and 7 mm. The distal canal showed the greatest dentin loss compared to other canals. Conclusion: Minimal access cavity designs (CEC and TrEC) demonstrated less CT and improved CA compared to the traditional access cavity design (TEC). Study limitations acknowledged that conservative access cavity designs result in less deviation (CT) and better centering of the prepared canals compared to the traditional approach (TEC). These results imply the potential benefits of adopting less invasive access cavity designs in endodontic practice to enhance treatment outcomes.

Shaping ability of HyFlex EDM and ProTaper Gold files with or without using glide path files: An in vitro study

Abstract Introduction: The necessity of using a glide path before the canal preparation is inconclusive. Therefore, this study aimed to assess the shaping ability of two rotary systems in the maxillary first molars’ first mesiobuccal canal (MB1), with or without employing the glide path files. Materials and Methods: The MB1 canals of 100 extracted molars were randomly prepared using either HyFlex EDM (HEDM) or ProTaper Gold (PTG) systems (n = 50 each). Half of the samples in each group were prepared using ProGlider (PG) or HyFlex EDM Glide (HEG). The cone-beam computed tomography scanning was conducted before and after the instrumentation. The canal transportation, centering ability, and remaining dentin thickness were evaluated and compared between the groups using the independent sample t-test and Mann–Whitney U-test (α =0.05). Results: Using HEDM compared to PTG led to greater centering ability at the sub-furcation area (P < 0.05), lower canal transportation at 2 mm below furcation (P = 0.025), and more dentin removed at the middle area (P = 0.011). The systems’ centering ability and canal transportation were comparable when path files were used. Utilizing HEG with HEDM decreased dentin removal at 2 mm below furcation (P = 0.045) and middle area (P = 0.008). Canal preparation with HEDM-HEG caused less dentin removal at 2 mm below furcation than PTG-PG (P = 0.007). Conclusions: The HEDM system outperformed PTG regarding centering ability in the sub-furcation areas and canal transportation 2 mm below the furcation. However, HEDM showed more dentin removal in the middle region than PTG, which was resolved when HEG was used. Therefore, using PathFile with the HEDM system might be suggested.

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.

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.

Cone-beam computed tomographic analysis of canal convolution in mesial root of mandibular second molars and a proposed new classification.

The aim is to evaluate the anatomical characteristics of mesiolingual and mesiobuccal canals in mandibular second molars particularly in terms of its exit direction, distance of confluence from the minor constriction, and the angle of confluence. The cone-beam computed tomography images of hundred mandibular second molars were analyzed. Endodontically treated teeth and those with anatomical variations such as C-shaped canal configuration were excluded from this study. The distance of the confluence from the minor constriction, angle of confluence, and the exit direction of the mesiobuccal and the mesiolingual canals were assessed. Data were analyzed using an independent t-test. The course of the mesiobuccal and mesiolingual canals beyond the confluence was towards the center of the root. The average angle of confluence was 32.75°-35.28°. The average distance of confluence from the minor constriction was 2.19 to 2.68 mm. The mesiolingual canal was straighter whereas the mesiobuccal canal had a tortuous course. Considering the results of the present study, a new classification has been proposed for the root canal morphology of the mesial root of mandibular second molars. The variation in the morphology of mandibular second molars highlights that the mesiolingual canal presented a mild curvature through and beyond the confluence when compared to the mesiobuccal canal which exhibited a tortuous course through the confluence.

The effect of cone beam computerized tomography voxel size and the presence of root filling on the assessment of middle mesial canals in mandibular molar teeth

IntroductionThe study aims to compare the detection of the middle mesial canal (MMC) in mandibular molar teeth using cone beam computed tomography (CBCT) with different voxel sizes when the mesiobuccal (MB) and mesiolingual (ML) canals have three distinct phases (unpreparation, preparation and obturation and the removal of the obturation and repreparation).MethodsTwo hundred forty-two extracted human mandibular molars were collected and kept in a physiological saline solution prior to use. 0.2-, 0.28- and 0.35-mm voxel sizes CBCT (n = 242) were performed in three phases (Ph): Ph1, no MB and ML canal preparation or obturation; Ph2, after MB and ML canals preparation and obturation; and Ph3, after the removal of the obturation of MB and ML canals and canals repreparation. Images were analyzed using OnDemand3D® software. After the CBCT acquisition in Ph3, all the samples were clarified to visualize the presence of the MMC directly. A blinded, previously calibrated examiner analyzed all the images.ResultsThe MMC was detected in 15 of the 242 teeth after the clearing technique. The lowest MMC detection rate was observed at 0.35-mm voxel size regardless of the ML and MB canal condition, while the highest was observed at 0.2-mm voxel size (P < 0.05). There is no statistically significant difference between 0.2-mm and 0.28-mm voxel sizes (P > 0.05). In all voxel sizes, the highest rate of detectability of the MMC was seen in Phase 1, while the lowest was in Phase 2.ConclusionsIt may be appropriate to take a 0.20-mm voxel size CBCT image, especially after the removal of root canal filling.Clinical relevanceAn appropriate CBCT voxel size and the absence of root canal filling in the root canal system help to detect the missing MMC.

Tooth Tissue Loss in Locating Mesiobuccal Canal during Selective Retreatment using Dynamic Navigation System: An In vitro Study

Selective root canal retreatment has demonstrated positive success, but the process is challenging because imprecision compromises the tooth's structural durability. As there is a lack of literature on selective retreatment using DNS, this in-vitro study was designed for comparative evaluation of tooth tissue loss and time taken in locating mesiobuccal (MB)canal using the dynamic navigation system (DNS; Navident, ClaroNav, Toronto, ON, Canada ) to the freehand (FH) method. The null hypothesis was that both methods would have similar tooth tissue loss and time required for the procedure. Twenty root canal-treated human mandibular molar teeth were mounted on Navident manikin. Using the Navident programme, the drilling path and depth were virtually designed using cone-beam computed tomographic (CBCT) scans. A minimal access cavity for locating the MB root was prepared with dynamic navigation in the DNS group and with freehand in the FH group. Volumetric tooth tissue loss was evaluated with the help of postoperative CBCT and On-demand software. Statistical analysis was done with an independent-sample T Test (p&lt;0.05). The time taken for the procedure was recorded with a stopwatch. The tooth tissue loss was significantly less with the DNS group (35.83 mm3) compared to the FH group (52.84 mm3) with a P value of 0.001. The time taken for the DNS group was less with the DNS group (29.00 seconds) compared to the FH group (53.60 seconds) with statistical significance with a P value of 0.001. The DNS resulted in minimal tooth tissue loss with a shorter time compared to the FH group. This technique can be practised for predictable selective retreatment in endodontics.

A Comparative Evaluation of the Efficiencies of Different Rotary File Systems in Terms of Remaining Dentin Thickness Using Cone Beam Computed Tomography: An In Vitro Study.

The aim of this study was to evaluate and compare the dentin thickness of the mesio-buccal canal of the lower first molar after canal preparation with three different rotary file systems using cone beam computed tomography (CBCT). TruNatomy (Dentsply Sirona, USA), 2Shape (Micro-Mega, France), and One Curve(Micro-Mega, France) were the three different rotary files that were employed. A total of 45 excised human permanent first mandibular molars were divided into Groups A (TruNatomy), B (2Shape), and C (One Curve) at random. To measure the residual dentin thickness at 3 mm, 5 mm, and 7 mm from the radiographic apex, the mesial root of the tooth was removed from the tooth, and a mesio-buccal canal was taken. Samples were mounted in clear acrylic resin and were subjected to a pre-instrumentation CBCT scan. The mesio-buccal canal was cleaned and shaped while maintaining the final mesio-buccal canal preparation of Group A - 26/0.04, Group B - 25/0.04, and Group C - 25/0.04. The samples were extensively irrigated with 3% sodium hypochlorite and 17% EDTA, and a post-instrumentation scan was performed on them. Statistics were used to determine the values from CBCT scans that were recorded for pre- and post-instrumentations. The results showed that Group A had the greatest drop in dentin thickness, followed by Group B and Group C. The change in dentin thickness was greatest at 3 mm and 7 mm. In contrast to TruNatomy and 2Shape rotary file systems, One Curve has the advantage of maintaining a tooth's thickness at 3 and 7 millimeters from the radiological apex. Since the TruNatomy file system removes more dentin than the other two combined, it should be used cautiously. Choosing the right instrument is crucial for cleaning and shaping during root canal preparation.

Effect of Movement Kinematics and Heat-Treated Alloys on the Apical Extrusion of Debris: An In Vitro Study

Background: Apically extruded debris can be affected by some features of the file systems such as kinematics or metallurgic properties. Aims: This in vitro study aimed to evaluate the effect of movement kinematics (reciprocation or rotation) and heat-treated alloys (C.Wire) on the amount of debris extrusion. Methods: Seventy-two mesiobuccal root canals were assigned into three experimental groups related to the single-file system used (n = 24): two rotational; One Shape (Conventional Ni-Ti), One Curve (C.Wire), and one reciprocating; and One Reci (C.Wire). The file systems were used according to the advisable speed and torque according to the manufacturers’ suggestion. The weight of debris was calculated by subtracting the preweights from postweights of Eppendorf tubes. Kruskall–Wallis and Mann–Whitney U tests were used to analyze the data (P = 0.05). Results: One Shape produced the greatest amount of extruded debris compared with One Curve (P &lt; 0.001) and One Reci (P &lt; 0.001), respectively. No statistical difference was found between One Curve and One Reci concerning amount of apical debris extrusion (P = 0.489). Conclusion: Metallurgical properties of files may affect apical debris extrusion. Alloy type is an important factor in the amount of debris extrusion. File kinematics does not affect apical debris extrusion.

Micro-Computed Tomography Analysis of Resin and Calcium Silicate Based Sealers Removal in Mandibular Molars Curved Canals.

The removal of the root canal sealer is an important factor in nonsurgical retreatment. The aim of this study was to compare the removal of AH Plus, Well Root ST, and AH Plus Bioceramic Sealer using Protaper Universal retreatment files. The curved mesio-buccal canals of extracted mandibular molars were prepared with the Protaper Gold file system (up to F2). Specimens were randomly divided into 3 groups and filled with the single cone technique using AH Plus, Well-Root ST, and AH Plus Bioceramic Sealer, respectively. After two weeks, the root canal filling of all specimens was removed using Protaper Universal retreatment files. All specimens were scanned using micro-CT. The remaining volume of the root canal filling was recorded in total and the coronal, middle, and apical third of each specimen. Well-Root ST and AH Plus Bioceramic Sealer groups had a higher percentage of total remaining filling material than the AH Plus group (P<0.05). This study has shown that the volume of remaining root canal filling was significantly higher in the samples filled with calcium silicate-based sealers.

Morphology and classification of the second mesiobuccal canal in maxillary first molars: a cone-beam computed tomography analysis in a Chinese population

BackgroundUnderstanding the tooth anatomy is crucial for ensuring effective endodontic treatment. This study investigated the root canal morphology of the second mesiobuccal (MB2) canal in maxillary first molars (MFMs) in a Chinese population using cone-beam computed tomography (CBCT).MethodsThis study evaluated 486 MFMs with MB2 canals from 285 participants undergoing CBCT examination and determined the Vertucci’s classification and position of the MB2 canal orifice. The prevalence of the MB2 canal was correlated with the sex, age, and tooth side. The correlations between the prevalence of the MB2 canal and sex and tooth side were assessed using the Fisher's exact test. The chi-square test was used for evaluating the correlation between the prevalence of the MB2 canal and age.ResultsThe number of type II, III, IV, V, VI, VII, and other root canals in the MFMs was 30.9%, 0.6%, 65.0%, 1.2%, 1.2%, 0.4%, and 0.6%, respectively. Among the 201 cases with bilateral inclusion, 87.6% showed consistent canal configuration. Results of the first clear apparent position (FCAP) of the MB2 canals showed that 434, 44, and 3 teeth had FCAP at the upper, middle, and bottom one-third of the root, respectively. The FCAPs of the MB2 canal in the MFMs with types II, IV, and VI, as well as types III and V canals showed significant differences (p<0.05). The horizontal distance between the MB1 and MB2 canal orifices in the type II canals of MFMs was significantly lesser than those in the type IV canals of MFMs (p < 0.01). The longitudinal distance between the pulp chamber floor plane and MB2 canal orifice significantly correlated with age (p < 0.05).ConclusionsThe morphology of the mesiobuccal root canal in the MFMs is complex. Complete understanding of the anatomical morphology of the root canal combined with the CBCT and dental operating microscope is necessary for the accurate detection of the MB2 canal and consequently improved success rate of root canal treatment. Our study findings can help endodontists improve endodontic treatment outcomes.

Frequency of Second Mesiobuccal Canal in Permanent Maxillary Molars: An Observational Study

Background: The success of root canal therapy in endodontics is heavily dependent on identifying a second mesiobuccal canal (MB2) in permanent maxillary molars. A comprehensive understanding of internal anatomy, particularly the recognition of MB2, is crucial for the effective treatment of this commonly encountered tooth. This study aimed to investigate the prevalence and occurrence of the second mesiobuccal canal in permanent maxillary first and second molars. Methods: This cross-sectional study that was conducted at the Department of Conservative Dentistry &amp; Endodontics, Military Dental Centre Dhaka, Bangladesh from January 2018 to December 2018. The analysis involved a total of 200 maxillary first molars and 200 maxillary second molars. In the initial phase for both groups, teeth were examined with the naked eye followed by microscopic assessment. Data analysis was conducted with MS Office tools. Results: In naked eye observation, the frequency of MB2 canals in the first molar teeth was found 64%, and in the second molar teeth it was found 56%. On the other hand, by microscopic assessment, the frequency of MB2 canals in the first molar teeth was found 96%, and in the second molar teeth, it was found 84%. Conclusion: The occurrence of the second mesiobuccal canal (MB2) in permanent maxillary first molars is more common than in the second molars. Microscopic assessment proves to be more effective than naked eye assessment for detecting the presence of MB2 in both maxillary first and second molars. J Bangladesh Coll Phys Surg 2024; 42: 133-138

An In-Vitro Study to Find the of Frequency of MB2 Canal in Permanent Maxillary Molars

Present in-vitro research conducted to find out the frequency of second mesiobuccal canals in permanent maxillary molars. Eighty extracted, intact maxillary permanent molars were selected for the present study. Following that, a slow-speed diamond disc was used to divide the occlusal sections of the crowns at the cement-enamel junction. Using a safe-end diamond bur, overhanging dentin that covered the canal orifices was removed to allow straight line visibility. Under an x8 magnification, the teeth were photographed from their occlusal side. Result showed that the first and second maxillary molars, MB2 canals were found in 70% and 55%, respectively. In conclusion it is crucial during endodontic procedures on maxillary molars to cautiously check pulpal floor to detect any "extra" canals, notably the second mesiobuccal canal, by scraping away the constrictive dentin above the orifices.

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.

Assessment of Mesiobuccal Canals in Endodontically Treated Teeth in Indore Population by Cone Beam Computed Tomography: A Cross-Sectional Study.

Owing to the complicated anatomical nature of maxillary molars, untreated root canals may directly affect the outcome of root canal therapy. Therefore, cone beam computed tomography (CBCT) scanis an important tool in the evaluation of root canal systems, particularly for the detection of the second mesiobuccal(MB2) canalin maxillary molars. The current study was undertaken to detect and evaluate filled/unfilled MB2 canals in endodontically treated, asymptomatic maxillary molars, and its correlation with periapical pathology by utilizing cone beam computed tomography (CBCT). A retrospective study of 80 CBCTs of patients underwent scanning for various treatment modalities, with asymptomatic endodontically treated permanent maxillary first molars selected. Data collection occurred between January and June 2023. CBCT machine used was KODAK 9000 (Rochester, NY: Carestream Health) (Complementary Metal Oxide Semiconductor {CMOS} sensor, continuous mode and 12-28 sec scan time, 90-500 μm voxel size, and 5x3.5 cm field of view {FOV}). The axial images at mid-root level were used to assess the presence of the MB2 canal. The study included 39 (48.8%) right maxillary first molars and 41 (51.3%) left maxillary first molars. Overall, in 62 (77.5%) maxillary first molars, MB2 was missed by the practicing dentist, and in 13 (16.3%) maxillary first molars MB2 canal was not present. Of all the maxillary first molars with MB2 canal (n=67), 53 (79.1%) canals had a periapical infection, five (7.5%) showed widening of periodontal ligament space whereas nine (13.4%) had no abnormality. MB2 canals were present in the majority of cases and most of the unfilled MB2 canals showed evidence of periapical radiolucencies and showed a direct impact on the prognosis.

Comparative evaluation of the efficacy of the Pro AF Baby Gold and Kedo-S pediatric endodontic files for canal instrumentation, transportation, and centering ratio - A systematic review and meta-analysis.

Traditionally, pediatric endodontics lacked access to the full potential of rotary instruments. These instruments, designed for the permanent root canal system, often presented limitations when used in primary teeth. To address this, exclusive pediatric rotary files with regular improvements have been introduced, featuring superior cutting efficiency with a focus on precise alignment. This design offers the advantage of reduced risk of ledges, perforations, instrument separation, and canal transportation. This study aimed to compare and evaluate the effectiveness of Pro AF Baby Gold and Kedo-S rotary files in preparing primary tooth root canals during pulpectomy procedures through a meta-analysis. The review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. The review searched electronic databases from 2000 to February 2024 for studies evaluating the efficacy of Pro AF Baby Gold and Kedo-S files in terms of canal instrumentation, transportation, and centering ratio. The Cochrane risk of bias (ROB)-2 tool assessed quality, with analyses conducted using RevMan software version 5.3. The standardized mean difference (SMD) served as the summary with a random effects model (P < 0.05). Out of the five studies identified through the eligibility criteria, three were deemed suitable for a meta-analysis, while all five were included in a qualitative synthesis. The quality assessment revealed a presence of moderate-to-low ROB. The pooled analysis using SMD did not show any statistically significant differences between the files, except for the centering ratio in the mesiobuccal canal, where the Kedo-S file performed slightly better. In addition, the absence of any significant asymmetry in the funnel plot suggests that there is likely no publication bias present in the data. Pro AF Baby Gold files can be used as an alternative adjunct in pediatric endodontics to Kedo-S files and manual files.Prospero Registration: CRD42023469406.

Apical periodontitis in endodontically-treated teeth: association between missed canals and quality of endodontic treatment in a Colombian sub-population. A cross-sectional study.

The aim of this study was to evalúate the quality of endodontic treatment and the frequency of missed canals associated with teeth with apicalperiodontitis (AP) through CBCTin a Colombian sub-population. This was a cross-sectional study assessing 318 cone beam computed tomography (CBCT) scans of endodontically treated teeth from Colombian individuals. The scans were taken using J Morita X550 (J Morita Corporation, Osaka, Japan), with voxel size 0.125 to 0.20 mm. All endodontically treated teeth were assessed for quality of treatment, presence of missed canals and AP. Allsamples were analyzed bytwo endodontics specialists and an radiology specialist. Chi-square or Fisher 's test and odds ratio were calculated to identify the association and risk relationship between the presence of AP and the study variables. Missed canals were found in 18.61% (86/462), and 95.3% were associated with AP. The frequency of AP was 62.34% (288/462) for all the evaluated teeth. AP was found in 27.43 % (79/288) of the teeth with adequate endodontic treatment, in contrast to 72.57% (209/288) of the teeth with inadequate treatment (P<0.01). The frequency of missed canals was highest in maxillary molars, with 55.23% (58/105), with 96.55% presenting AP. The second mesiobuccal canal wasthe most frequently missed canal, 88.52%o(54/61), with AP in 90.74% (49/54) of the cases. There was a high frequency of teeth with missed canals and PA. More than half of the teeth with missed canals were maxillary molars, with MB2 being the most common canal, commonly presenting apical periodontitis.

FREQUENCY OF SECOND MESIOBUCCAL CANAL IN PERMANENT MAXILLARY SECOND MOLARS AT A TERTIARY CARE CENTRE OF NEPAL

Background: The success of endodontic treatment relies on the precise identification of root canals followed by cleaning, shaping, and obturating the canals. Mesiobuccal root of maxillary second molar teeth present wide variations with regard to the number and type of root canals. The complexity of the root canal varies widely in different ethnic groups. The study aimed to determine the prevalence of second mesiobuccal canal (MB2 canal) in maxillary second molar. Methods: A descriptive cross-sectional study was conducted at Department of Conservative Dentistry and Endodontics, Universal College of Medical Sciences, Bhairahawa. A total of 100 permanent maxillary second molar undergoing endodontic treatments were studied. After access cavity preparation ultrasonic tips and magnification loupes were used to open the subpulpal groove in a direction from first mesiobuccal (MB1) canal towards the palatal canal to locate the second mesiobuccal (MB2) canal. Radiovisiography (RVG) was taken to confirm the presence of MB2 canals. Results: MB2 canals were detected in 52 teeth out of 100 teeth that were studied. It was found that the younger adult (18-35 years) tends to have a higher proportion of MB2 canals (65.6%) as compared to the middle-aged elderly (36-55years) in whom it could be identified only 33.4% of the time. Conclusions: Based on this study, it can be concluded that the prevalence of MB2 canal in mesiobuccal root of the permanent maxillary second molar is high.

Management of Separated Endodontic Instrument in Mandibular Second Molar with Bypass Technique

One of the most common mishaps in root canal treatment is a separated endodontic instrument. Bypass technique is an effective alternative besides file retrieval while clinical conditions have lack of access and visibility. Other than, this technique gives a more conservative outcome because it prevents more dentin removal. The aim of this case report was to describe management of separated endodontic instruments in the mandibular second molar with bypass technique during endodontic treatment. A 3,5 mm F1 ProTaper Hand Use file was separated in the mesiobuccal canal of the mandibular second molar. Radiograph examination was taken to make sure the level of fragment. Bypass was performed with #10 until #25 K-File to pass the separated instrument through the gap between it and the root canal wall. Obturation has been done with gutta percha and resin-based sealer using cold lateral condensation technique. Direct restoration was chosen as final restoration after 6 days follow up. Bypass technique can be performed as management of separated instrument considering the risks involved fragment extrusion to apical region, secondary separated instrument, and conservative aspect.