Distobuccal Canals Research Articles

Endodontic treatment in a maxillary second molar with four root canals: A case report

Endodontic treatment is based on an understanding of the internal anatomy, which facilitates the precise exploration of the canals. The present study aimed to report a clinical case referring to the endodontic treatment of the upper left second molar, presenting the mesiopalatal canal and communication with the periodontal tissues in the distal region of the pulp chamber, in the furcation region, due to dental caries. The 41-year-old patient did not present any systemic health problems. The treatment was divided into three sessions. In the first consultation, the diagnosis of pulpal necrosis was obtained with a periapical area without changes in normality, no pain on vertical and horizontal percussion, in addition to no pain on palpation at the bottom of the sulcus and around the tooth. The radiographic examination revealed a vast region suggestive of caries in the distal region of the tooth crown, so the carious tissue was removed and the pulp chamber was accessed. In the second session, disinfectant penetration, working length determination, and instrumentation of the root canals were performed with the Reciproc R25 system for the mesiopalatal, mesiobuccal, and distobuccal canals, and R50 for the palatal canal. Bio-C Temp was used as an intracanal medication. After 18 days, the root canals were filled with apical gutta-percha cones and Bio-C Sealer, a silicate-based cement. Then, the communication in the furcation region was sealed with the repair cement, Biodentine. The pulp chamber floor was sealed with light-curing glass ionomer, and the pulp chamber was filled with composite resin.

Root Canal Preparation of a Commercial Artificial Tooth versus Natural Tooth—A MicroCT Study

This study aimed to evaluate by microCT the preparation of the artificial teeth (ATs), TrueTooth®, versus natural teeth (NTs): (1) the time and number of pecking movements needed for preparation; (2) the root canal volume increase; (3) if the pulp-colored medium has any effect on the 3D analysis. Material and Methods: Artificial and natural maxillary molars were used. Fourteen AT distobuccal canals and fourteen NT buccal canals were used for the first and second aim and fourteen AT mesiobuccal canals for the third aim. Results: No statistically significant differences were observed regarding the time and number of pecking movements (p > 0.05); for the root canal volume increase, a statistically significant difference was observed (p < 0.05) with a higher mean value for NTs; however, in the group of ATs, there was a volume decrease in three cases. The AT mesiobuccal root canal mean volume increase was also negative. Conclusions: There are no differences between the time and number of pecking movements between NTs and ATs, so TrueTooth® can potentially be used in endodontic training. The volume increase between ATs and NTs was higher in NTs. However, some samples showed negative values, also seen in the AT mesiobuccal canal, confirming that the pulp-colored medium has an effect on the 3D analysis.

Effect of the progressive taper enlargement of buccal root canals of three-rooted maxillary molars: A stepwise micro-CT study.

This study evaluated unprepared canal areas, volume of dentine removal, and dentine thickness after the progressive enlargement of the buccal canals of 22 maxillary molars, with and without the MB2, using instruments with the same tip size (0.25 mm) but 4 different tapers (0.03, 0.05, 0.06 and 0.08 v). Micro-CT scans were performed after each instrument. Data were compared using a general linear mixed model post hoc comparisons with Kenward-Roger for Wald F tests (α = 5%). After each treatment step, it was observed an increase in the percentage volume of removed dentine and a decrease in the unprepared areas and dentine thickness at the pericervical region of all canals (p < 0.05). The percentage reduction of dentine thickness in MB2 canal was higher than in the mesiobuccal and distobuccal canals (p < 0.05). Knowledge of pre-operative dimensions and dentine thickness before enlargement of buccal canals of maxillary molars is an important factor to avoid excessive dentine removal.

Finite element analysis of maxillary first molar with mesial-occlusal-distal-palatal defect restored with different post-and-core strategies

PurposeTo explore which restoration strategy generates the most favorable stress distribution in an endodontically-treated maxillary first molar with mesial-occlusal-distal-palatal defect. MethodsModels with one post in palatal canal (PP), each post in palatal and distobuccal canals (PDP), each post in palatal and mesiobuccal canals (PMP), and each post in all canals (PDMP) were established for an endodontically-treated maxillary first molar with mesial-occlusal-distal-palatal defect either with fiber-reinforced composite (FRC) post or gold alloy cast (GAC) post. A 400-N vertical force and a 225-N lateral force were respectively applied. The Mohr-Coulomb stress ratio (σMC ratio) in the residual tooth structure (RTS), the resin cement, and the crowns, the tensile stress (σt) and compressive stress (σc) in the FRC posts, the von-Mises stress ratio (σvM ratio) in the GAC post-and-cores, and the σt and shear stress (σs) at the adhesive interfaces were calculated using finite element analysis. ResultsFRC posts generated lower σMC ratio than GAC posts in the RTS (0.3274–0.3643 vs. 0.3399–0.4118). Among the FRC post groups, the PDMP group got the lowest σs at the dentin-post interface (14.92 MPa) and the abutment-crown interface (8.242 MPa) under vertical loading, as well as the lowest σMC ratio in the RTS (0.3381) and the lowest σs at the dentin-post interface (38.00 MPa) under lateral loading. ConclusionsFrom the point of stress distribution, placing FRC posts in the palatal, distobuccal, and mesiobuccal canals is the optimal strategy in restoring a severely damaged maxillary first molar, provided that lateral occlusal force is reduced.

The Biomechanical Behaviour and life span of a Three-Rooted Maxillary First Premolar with Different Access Cavity Designs: A Finite Element Analysis.

The present study aimed to evaluate the influence of different access cavity designs on the biomechanical behaviour of a three-rooted maxillary first premolar using finite element analysis (FEA). Three experimental FEA models were generated: the intact tooth (IT) model, the traditional access cavity (TAC) model, and the conservative access cavity (CAC) model. In both TAC and CAC models, root canals preparation was simulated as follows: the mesiobuccal and distobuccal canals with a final tip size of 30 and taper of 0.04 and the palatal canal with a final tip size of 35 and taper of 0.04. Cyclic loading of 50 N was simulated on the occlusal surface of the three models. The number of cycles until failure (NCF), the location of failure, stress distribution patterns, maximum von Mises (VM), and maximum principal stress (MPS) were all evaluated and compared. Both types of access cavity preparation caused a reduction in the lifelog of the tooth; when compared to the IT model the TAC model had a lifelog of 94.82% while the CAC model had a lifelog of 95.80%. The maximum VM stresses value was registered on the occlusal surface of the TAC model (7 MPa), while the minimum was on the occlusal surface of the IT (6.2 MPa). MPS analysis showed that the highest stress value was recorded on the occlusal surface of the CAC model (7.71 MPa), while the least was recorded on the occlusal surface of the TAC model (3.77 MPa). Radicular stresses were always of minimal value regardless the model. The relation between the access cavity margins and the functional load points is a deciding factor that influences the biomechanical behaviour and fatigue life of endodontically treated teeth. (EEJ-2023-01-03).

Influence of Apical Patency on the Adaptation of the Master Filling Cone: A Cone-beam Computed Tomography Assessment.

This study aimed to evaluate if the apical patency can influence the adaptation of the master cone of gutta-percha, quantifying the volume of voids and areas at the last 2 mm of the working length (WL). Sixty distobuccal canals of extracted upper molars were divided into 3 groups (n=20) based on the patency length (A: passed 1 mm beyond the apical foramen (AF), B: at the AF and C: 1 mm short of the AF) with the Easy ProDesign Logic 25/0.01 file. Each group was subdivided into 2 subgroups (n=10) based on the WL established to prepare the root canal (1: 1 mm short of the AF or 2: at the AF) with the Easy ProDesign Logic 25/0.05 file. After the scan, void volumes were calculated from the last 2 mm of the WL and void areas at 0 mm, 1 mm and 2 mm of the last of WL, as well as the relation between the tip and taper of the master cone with the amount of void volume and areas. To investigate statistically significant differences, we used the Kruskal-Wallis statistical test. There were more voids in volume when patency was achieved 1 mm beyond the AF and the root canal preparation was conducted at 1mm short of the AF (A1 group). Furthermore, the same group showed more voids areas, mainly on the last millimeter of WL. Achieving apical patency at 1 mm beyond the AF followed by instrumentation 1 mm short of the AF created more voids between the master gutta-percha cone and the root canal wall, especially on the last millimeter of WL.

Micro-CT Analysis of the Root Canal Configuration of Maxillary Second Molars with Fusion

Purpose: The present study investigated the root canal configuration of maxillary second molars with root fusion using micro-computed tomography (micro-CT).&#x0D; Materials &amp; Methods: A total of 136 fused maxillary second molars were scanned with micro-computed tomography. Images were transferred to CTAn v.1.18.8 software (Bruker-microCT) to obtain three-dimensional models. The specimens were classified according to the fusion type. According to Vertucci, classification of the root canal configuration of fused roots was determined using CTVol v. 2.3.2.0 (Bruker-microCT) and DataViewer v.1.5.6 (Bruker-microCT) softwares. The specimens that could not be represented were also specified. The frequency of canal configuration according to the fusion type was calculated.&#x0D; Results: For Type 1 fusion (n=40) and Type 2 fusion (n=22), the most common canal configuration for mesiobuccal (MB), distobuccal (DB) and palatal (P) canals was Type I. In type 3 fusion specimens (n = 21), DB and P canals were completely fused in 1 sample in accordance with Vertucci type IV, while in the remaining specimens, types II, I, V, VI and IV were observed in decreasing order in the MB canal. In type 4 fusion, MB and DB canals were completely fused in 4 of 21 specimens and showed Vertucci type VI, II, I and III configurations. In the remaining 17 samples, MB had Vertucci type I, II, IV, V, VI, VII configurations, while DB showed type I, V and III configurations. In 7 samples with type 5 fusion all canals displayed different configurations. In type 6 fusion, the canal configurations of 6 samples could not be classified. Type II, I, and V configurations were seen in 9 of the remaining 19 samples with a single canal.&#x0D; Conclusion: Vertucci type I was the dominant canal configuration in the P and DB, however, MB showed much more diverse configurations either independently or when included in fusion.

Assessment of the prevalence and configuration of middle distal canals in the mandibular molars in a Saudi subpopulation using Cone-Beam computed tomography

PurposeThe prevalence of the middle distal (MD) canal in the mandibular molar is significantly low among countries including the USA, Spain, Turkey, and Jordan; however, analysis of its prevalence and configuration has not been performed in Saudi Arabia. Therefore, we aimed to assess the prevalence and configuration of the MD canal in Saudi Arabia. MethodsA retrospective analysis of 132 cone-beam computed tomography (CBCT) images was performed to evaluate the presence of the MD canal in patients visiting the Radiology Department of The College of Dentistry in King Saud University between July 2018 and July 2019. The canal was examined if it was confluent with the distobuccal (DB) or distolingual (DL) canals, fin, or independent. Moreover, the distances from the MD canal to the DL and DB canals and cementoenamel junction (CEJ) were recorded. ResultsOne MD canal (0.7%) was observed in 145 teeth. It was confluent with the DL canal. No statistical significance was observed among sex and age. The distances from the MD canal to the DL canal, DB canal, and CEJ were 1.4 mm, 1.9 mm, and 3.1 mm, respectively. ConclusionsThe prevalence of the MD canal was significantly low in a Saudi subpopulation (0.7%). Careful evaluation of CBCT images and the pulpal floor is significantly important to detect the MD canal to ensure a good prognosis.

Fracture Incidence of Kedo-S Square Pediatric Rotary Files: A Prospective Clinical Study.

Objective The primary focus of this clinical study was to analyze the probability of occurrence of instrument fracture after root canal preparation of primary molars with the help of Kedo-S Square pediatric rotary file. Materials and Methods Three experienced specialists treated 100 primary maxillary and mandibular molars (335 root canals) using a standardized protocol over 2 months. Biomechanical preparations were carried out using Kedo-S Square file, as per the suggestions given by the manufacturer. Every instrument in Group A helped handle three clinical cases, while for groups B, C and D, they helped in handling 5, 9, and 12 cases, respectively. Making use of an operational microscope, the rotary files, after being pulled out from the canal, were observed. The values were tabulated, and descriptive statistics were performed. Results There were two fractures (2%), of which 1 occurred in group C in the apical 1/3rd of distobuccal canal of maxillary molar, and the other occurred in group D in the apical 1/3rd of mesiobuccal canal of maxillary molar. Conclusions The fracture rate of Kedo-S Square rotary file is quite low. It is primarily in the buccal canals of the maxillary molars and the apical third of the root canal that the instrument has a greater probability of separation.

Er:YAG Laser-Activated Irrigation in Comparison with Different Irrigation Systems for Cleaning the Apical Root Canal Area Beyond Ledge.

Objective: To evaluate the effectiveness of erbium:yttrium aluminum garnet (Er:YAG) laser-activated irrigation (LAI) for cleaning the apical root canal area beyond a ledge. Background data: This was the first study that evaluated the efficacy of LAI in debris and smear layer removal from such hard-to-reach canal areas in human teeth. Methods: Eighty-eight human maxillary molars with either a mesiobuccal or distobuccal canal with 25°-35° curvature and mature apices were used. Following instrumentation to a size 25/0.02 taper, a ledge was created at 2.2 ± 0.7 mm short of the apex and checked using microcomputed tomography. Samples were divided into four groups: syringe irrigation (SI), ultrasonic-activated irrigation (UAI), agitation with the XP-endo Finisher (XP), and LAI. Each group was subdivided based on the irrigation regimen: 9 mL of 6% sodium hypochlorite (NaOCl), and 6 mL of 6% NaOCl +3 mL of 14.3% ethylenediaminetetraacetic acid (EDTA) (n = 11). The apical 1-mm region was examined using scanning electron microscopy to evaluate the remaining debris and smear layer. Data were analyzed using the Kruskal-Wallis test and Mann-Whitney U test (a = 0.05). Results: Regardless of the irrigants used, LAI showed significantly lower smear layer scores than SI and XP (p < 0.05), with insignificant difference as compared with UAI. LAI showed significantly better debris removal than SI (p < 0.05) when NaOCl alone was used. Conclusions: In the apical area of ledged canals, the cleaning efficacy of Er:YAG LAI with/without EDTA was higher than SI and XP, but was comparable with UAI. Clinical Trial Registration number D2014-33.

Three-dimensional analysis of coronal root canal morphology of 136 permanent mandibular first molars by micro-computed tomography

Background/purposeMinimally invasive endodontic approach become a research hotspot and may prevent the fracture of endodontically-treated teeth. This research aims to measure the coronal root canal morphology of permanent mandibular first molars in 3D and propose a new minimally invasive endodontic approach based on this measurement.Materials and methodsData of 136 permanent mandibular first molars were involved and reconstructed in 3D models with canals. Then, the morphology characteristics of the coronal root canal were measured.ResultsOverall, the distribution of root canal orifices was more centralized than other landmarks. The landmarks were located more mesiobuccally to the center of the occlusal plane of molars. Specifically, the measurements of the maximum curvature of coronal root canals in the axial direction were: in 3-canals 2-rooted teeth, the average angles of curvatures were 23°,25°,11° for mesiobuccal (MB), mesiolingual (ML) and distobuccal (DB) canals, respectively; in 4-canals 2-rooted teeth were 23°,25°,12°,16°for MB, ML, DB, and distolingual (DL) canals, respectively; in 4-canals 3-rooted teeth were 25°,27°,17°,39° for MB, ML, DB, and DL canals, respectively. The degrees of coronal root canal curvatures in the horizontal direction were: in 3-canals teeth, the average angles of curvatures were −1°,47°,-2° for MB, ML and DB canals, respectively; in 4-canals 2-rooted teeth were −4°,41°,-25°,48° for MB, ML, DB, and DL canals, respectively; in 4-canals 3-rooted teeth were −3°,33°,-43°,79° for MB, ML, DB, and DL canals, respectively.ConclusionThe results of this study are similar to those previously obtained using CBCT and can help us design endodontic approaches.

Endodontic guides and ultrasonic tips for management of calcifications

Aim: To describe the role of guided endodontics with ultrasonic tips in management of calcified canals. Summary Case 1: A 23-year old female presented with esthetic complaint related to the maxillary left central incisor with a history of trauma. Radiographic examination revealed internal resorption and apical calcification. A silicone impression of the maxillary jaw was obtained and scanned to plan for access of the calcified canal by means of implant planning software. Guides were fabricated through rapid prototyping and allowed for the correct orientation of an ultrasonic tip to provide access through the calcifications. An access cavity was done, the calcified canal was accessed by the help of the fabricated guide, and the root canal was prepared and obturated using warm vertical technique apical to the resorptive defect. The rest of the canal was filled with mineral trioxide aggregate (MTA). One-year follow-up revealed no symptoms and evidence of radiographic healing. Case 2: A 43-year old male was referred for endodontic treatment of the maxillary right first molar. The mesiobuccal and palatal canals were prepared by the referring dentist who failed to locate the distobuccal canal. Radiographic examination revealed a previously initiated root canal therapy, widening of the periodontal membrane space and coronal calcification of the distobuccal canal. A silicone impression of the maxillary jaw was obtained and scanned similar to the first case. The distobuccal canal was located using the ultrasonic tip through the guide, prepared, and obturated using warm vertical technique. One-year follow-up revealed no symptoms and evidence of radiographic healing. Key Learning Points Endodontics guides with ultrasonic tips are reliable in management of root canal calcifications. Three-dimensional imaging using CBCT and CAD/CAM provides accurate 3D guides.

Role of Comprehensive Diagnostic, Imaging and Treatment Strategies in Endodontic Retreatment of a Maxillary Molar with Unusual Anatomy: A Case Report

An appreciation of the anatomic complexity of the root canal system is essential at every step of endodontic treatment. Endodontic treatment of teeth with unusual root canal anatomy presents a unique challenge. This clinical case report presents the application of cone beam computed tomography as a useful imaging technique in endodontics for the management of teeth with aberrant anatomy. Failure to detect an extra canal may lead to treatment failure. The current report presents the management of a previously endodontically treated maxillary first molar with missed additional mesiobuccal and distobuccal canals. Keywords: CBCT, Canal Morphology, Maxillary molar, Missed canal, Retreatment.

Prevalence of Missed Canals and Their Association with Apical Periodontitis in Posterior Endodontically Treated Teeth: A CBCT Study.

Background This study aimed to assess the prevalence of missed canals in endodontically treated teeth and their association with apical periodontitis in a Saudi Arabian population using CBCT. Materials and Methods A total of 208 CBCT radiographs were investigated. For each tooth, radiographs of axial, coronal, and sagittal segments were acquired to appraise the external as well as the internal structure of the root canal system and apical area. In root canal-treated teeth, unfilled canals appearing from the cementoenamel junction to the apex were defined as missed untreated canals; and a periapical lesion was considered when disruption of the lamina dura was detected, and the low-density area associated with the radiographic apex was at least twice the width of the periodontal ligament space. The data were presented as frequencies and percentages. The Z-test was used to analyze the differences in proportions with the significance level set at P value <0.05. Results The overall prevalence of missed canals among endodontically treated teeth was 18%. The prevalence of missed canals was higher in maxillary first molars with 40.6%. The overall prevalence of apical periodontitis among teeth with missed canals was 90%. It was 84.2% in the maxilla and 100% in the mandible. The second mesiobuccal canal in the maxillary first molars and mesiobuccal and distobuccal canals in mandibular teeth were the most missed canals. Conclusion Apical periodontitis in root canal-treated teeth with missed canals was high (90%), with most identified missed canals in maxillary and mandibular first molars.

Examination of root canal morphology of teeth affected by Molar Incisor Hypomineralization (MIH): Frequency of accessory canals

Aim: The aim of this study was to investigate the incidence of the presence of accessory canals in the root canal of the maxillary first molar teeth affected by Molar Incisor Hypomineralization (MIH).Methodology: A total of 12 maxillary first molar teeth affected by MIH were obtained from 10 children aged from 10 to 12 years. The frequency of the presence of accessory canals was examined by using microcomputed tomography and 3D image software. Results: Accessory canals were observed in the mesiobuccal (MB) canal in all of the samples with a statistically significant difference.(p&lt;0.05) It was observed that the accessory canals were mostly in communication with the canals in the MB root and that furcal accessory canals were found in 10 (83.33%) teeth. The incidence of accessory canals was 75% in the distobuccal (DB) canal and it was 66.66% in the palatal (P) canal.Conclusion: The incidence of the presence of accessory canals in DB and P canals and furcation is higher in the teeth affected by MIH.&#x0D; &#x0D; How to cite this article: Özükoç C. Examination of root canal morphology of teeth affected by Molar Incisor Hypomineralization (MIH): Frequency of accessory canals. Int Dent Res 2021;11(1):12-5. https://doi.org/10.5577/intdentres.2021.vol11.no1.3&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Comparison of Obturation Quality after MTA Orthograde Filling with Various Obturation Techniques.

This study aimed to quantify and compare the obturation quality after mineral trioxide aggregate (MTA) orthograde fillings with three different obturation techniques. Thirty-three extracted human maxillary molars were collected. Distobuccal and palatal canals were prepared to an apical size of #40/06 with a Profile Ni-Ti system. All 66 canals were divided into two groups according to the material (EZ-seal or OrthoMTA) and then obturated using three different techniques: manual compaction using S-kondenser (group H), compactor activation (group C), or reverse rotary motion of Ni-Ti file (group R). The obturated roots were scanned using micro-computed tomography (micro-CT). The percentage of voids located in the apical 5 mm was measured separately, that is, closed, open, and total porosity. There was no relation between the filling material and obturation technique (p > 0.05). The percentage volume of open and total porosity was higher in EZ-seal than in OrthoMTA (open: p = 0.002, total: p = 0.001). Group H showed higher open and total porosity than groups C and R. Micro-CT analysis showed that the void volume after orthograde MTA fillings significantly decreased when the additional activation was accompanied by hand condensation. Obturation with a Ni-Ti file using reverse motion could be recommended as an MTA orthograde filling technique.

The Efficacy of Reciproc Blue® For Canal Cleanliness Following the Retreatment of Maxillary First Molar: In Vitro Analysis

Nonsurgical retreatment involves removing mechanical barriers such as gutta-percha to achieve proper cleaning and disinfection. The complexity of the anatomy of molar tooth gives challenge in retreatment procedure. Thus, this study evaluates the amount of residual gutta-percha after retreatment with rotary files (Reciproc Blue®) from each maxillary first molar canal using cone-beam computed tomography (CBCT) and the time required to accomplish it. Nine freshly extracted maxillary molars were instrumented and obturated. Preoperative CBCT was taken, and retreatment was done using Reciproc Blue®. CBCT was taken post retreatment, and the residual volume percentage of gutta-percha from each canal was calculated. The total retreatment time was recorded, and the data were statistically analyzed. The result shows no statistically significant difference in the amount of residual filling material in mesiobuccal, distobuccal, and palatal canal for maxillary first molar and total time used for retreatment with Reciproc Blue® system.

Geometric Analysis of the Distolingual Root and Canal in Mandibular First Molars: A Micro–computed Tomographic Study

IntroductionThe purpose of this study was to comprehensively assess by micro–computed tomographic imaging the anatomic features of distolingual (DL) roots and canals in mandibular first molars collected from 1 population. MethodsOne hundred two specimens were examined for the location and initial direction of the DL canal and the relationship between the distance of apical deviation and the angle of root curvature. ResultsAll DL roots had only 1 canal. A new 7-category classification system is proposed for the DL roots of mandibular first molars. Most DL roots were type IV (28 teeth), type III (26 teeth), and type V (25 teeth). The average canal curvature in all root types was over 25°. There was a positive correlation between the angles of root and canal curvature for types II, IV, and V (P < .05) but not for types I and III (P > .05). In the buccolingual view, most DL roots were straight, whereas in the mesiodistal view the root curvature was close to the maximum value. The orifice of the DL canal was 4 times further from the line that bisects a line between the mesiobuccal and mesiolingual canal orifices than the distobuccal canal. The angle between the mesiobuccal-mesiolingual line and the horizontal projection of the coronal third of the DL canal on the pulp floor was 8.1° ± 10.0° and 6.1° ± 8.2° for teeth from the left and right side, respectively. The angle between the inserted simulated file and the cementoenamel junction was 57.9° ± 6.3°. Seventy-three percent of the DL canals had no constriction in the apical area. The DL canals were narrow and had a conical frustum-like shape with a 0.04 taper at the apical portion. ConclusionsThe novel classification of the DL roots helps to better understand the clinically challenging anatomy of the root and canal.

Safety of large preparation with different instruments in the buccal canals of maxillary molars.

This study aimed to evaluate the influence of large apical preparations with Reciproc (REC), Hyflex CM (HCM) and Twisted File Adaptive (TFA) systems using micro-computed tomography (MCT). Ninety mesiobuccal (MB) and distobuccal (DB) root canals of maxillary molars (n=45) were scanned using MCT before and after the shaping procedures. The root canals (n=15) were prepared until REC 40.06, HCM 40.04 and TFA 35.04. The root canal transportation (RCT), centring ability (CA), change in volume of the root canal and at different levels (VC), remaining dentine thickness (RDT), removal of dentine wall (RDW) and working time (WT) were evaluated. Data were analysed using the Kruskal-Wallis and Dunn tests, and the one-way ANOVA and Tukey tests with a level of significance set at 5%. No significant difference among the instruments was found regarding the RCT, CA, RDT, RDW and WT (P>0.05), in larger apical preparations in curved MB and straight DB canals of maxillary molars.

Guided Endodontic Access in a Maxillary Molar Using a Dynamic Navigation System

The treatment of calcified root canals is challenging in endodontic practice. A 63-year-old man was referred to the postgraduate endodontic clinic at the University of Maryland School of Dentistry, Baltimore, MD, for the treatment of tooth #3. Because of the patient’s history of head and neck radiation and the high risk of developing osteoradionecrosis, a nonsurgical endodontic approach was found to be the most reasonable treatment option despite the questionable prognosis of the tooth. During the endodontic treatment, the distobuccal canal appeared to be partially calcified and was not possible to be located freehand even with use of the dental operating microscope and cone-beam computed tomographic approximated approach. Therefore, the dynamic navigation system using the X-Guide system (X-Nav technologies, LLC, Lansdale, PA) was used, which allowed for the successful location of the canal. Conventional endodontic treatment was completed following standardized instrumentation, irrigation, and obturation. Details on how to use the dynamic navigation system are described including its advantages, disadvantages, and limitations.