Root Of Maxillary First Molar Research Articles

Comparative analysis of incidence of dentinal defect with different taper of rotary instrument use stereomicroscope

Aims: Study the effect of canal preparation with different Niti rotary system (Edge x7 file and F-one file) with different taper (0.04 and 0.06) on the incidence of dentinal defect. Methods and Material: 75 straight palatal root of maxillary first molar were collected, the instrumentation was done to 11 mm root length for all sample except control group, the sample were divided randomly into five group (n=15), Group (A) was a control, Group (B) with Edge x7 taper (0.04), Group (C) with Edge x7 taper (0.06), Group (D) with F-ONE taper (0.04), and Group (E) with F-ONE taper (0.06) Every sample had a horizontal section from the apex at 2 mm, 4.5 mm, and 7 mm, dentinal defect was evaluated with 25x stereomicroscope. Statistical analysis used: The data were statistically evaluated at significance levels of 5% or more using Fisher's exact test. Results: Ther is no significant difference between different taper and between different file, in general taper 0.04 showed less dentinal defect than taper 0.06, and Edge x7 showed less defect than F-ONE. Conclusions: Dentinal defects were present in all experimental groups, but not in control group. Key-words: Edge x7, AF Fanta, dentinal defect, stereomicroscope

Quantitative Measurement of Buccal Cortical Bone Thickness in Infrazygomatic Crest Area at Different Alveolar Bone Heights and Insertion Angles of Infrazygomatic Crest Screws: A CBCT Study

Introduction Skeletal anchorage devices for the efficient orthodontic treatment mechanics can be placed at various interradicular and extraradicular sites intra orally. However, their placement in the infrazygomatic crest area can broaden the horizon of orthodontic treatment. The bone thickness in the infrazygomatic crest (IZC) area can vary at different heights and insertion angles during the placement of IZC screws between maxillary second premolar and second molar region. Aims and objectives The purpose of our study was to evaluate the variation in bone thickness in the IZC area at different insertion angles along the mesiobuccal root of maxillary first molar and at different heights from the crest of the alveolar bone in the apical direction between maxillary second premolar and second molar region using cone beam computed tomography, so as to determine the best possible site where the bone thickness will be maximum that will suit to a particular size of IZC screw. Materials and Methods CBCT images of 50 subjects were analyzed by a single observer, the bone thickness in the IZC area was measured and interpreted at different heights from the alveolar crest in the apical direction, that is, 5 mm, 7 mm, 9 mm, 11 mm at six regions between maxillary second premolar and second molar. Bone thickness was also measured at different insertion angles ranging from 55º to 75º to occlusal plane of permanent maxillary first molar along its mesiobuccal root. Results The bone thickness in the IZC area was 4.5 mm–3.5 mm, when it was measured at different angles ranging from 55º to 75º to the occlusal plane of maxillary first molar along its mesiobuccal root with maximum bone thickness at 75° with a mean ± SD of 4.56 ± 1.4. Statistically significant differences in bone thickness were found between maxillary first and second molar on both right and left sides at different heights with maximum bone thickness at 11 mm apical from the alveolar crest with a mean ± SD of 2.03 ± 0.76 and 1.91 ± 0.88, respectively, and along the mesial root of maxillary second molar on right and left sides at 11 mm apical from the alveolar crest with a mean ± SD of 2.12 ± 0.80 and 1.95 ± 0.75, respectively. Conclusions The best site and safe zone for miniscrew insertion in IZC area is at 7 mm to 9 mm distance from the alveolar crest apically along the mesial root of maxillary second molar and at an angle of 55°–75º to the occlusal plane of maxillary first molar, so as to ensure the adequate stability of the miniscrew and without causing any damage to the adjacent anatomical structures.

Evaluation of Canal-centering Ability and Apical Transportation of Hyflex-EDM, OneShape, WaveOne Gold, and Reciproc Files: An Ex Vivo Study.

To evaluate and compare canal-centering ability (CCA), canal transportation (CT), and dentinal crack formation by using Hyflex-electrical discharge machining (EDM), OneShape, WaveOne Gold, and Reciproc single file system in the mesiobuccal root of maxillary first molar at coronal, middle, and apical third using cone-beam computed tomography (CBCT) and scanning electron microscopy (SEM). Mesiobuccal roots of 120 freshly extracted maxillary molar teeth were divided into four experimental groups; Hyflex-EDM, OneShape, WaveOne Gold, and Reciproc (n = 30/group). Preinstrumentation scanning was done using CBCT for all samples at coronal one-third (4 mm), middle one-third (8 mm), and apical one-third (12 mm). After cleaning and shaping with standard irrigation protocol, the specimens were again scanned. Canal-centering ability and CT were calculated using pre- and postinstrumentation CBCT values. A scanning electron microscope was used to identify dentinal crack formation. No significant difference was found for CCA by any of the systems at coronal, middle, and apical third, respectively. However, OneShape was found to have better CCA at the coronal third and WaveOne Gold at the middle and apical third. There was a significant difference in canal transportation at the apical third (p = 0.004) with WaveOne Gold having the least CT followed by Reciproc at the apical third. OneShape resulted in more dentinal cracks in the coronal and middle thirds. Also, Hyflex-EDM was better in the apical third. No difference in CCA was observed between the groups. The lowest values for CT were obtained for WaveOne Gold (similar to Reciproc) whereas both rotary files showed higher values for CT. Also, OneShape showed the most dentinal at all levels. Furthermore, Hyflex-EDM and WaveOne Gold produced the least dentinal cracks at all levels. Given that the Reciprocating file system had the least CT and least dentinal cracks, the clinical success rate of root canal treatment (RCT) with the Reciprocating file system can be a better choice to improve the longevity of root canal-treated teeth.

Morphometric relationships in mesio-buccal roots of maxillary first molars in Saudi subpopulation: A CBCT study.

This CBCT-based study analysed morphometric relationships in Mesio-Buccal (MB) roots of maxillary first molars (MFM). 133 MFM with two MB canals were assessed and classified using Vertucci's classification. MB roots' length and MB1-MB2 canals inter-orifice distances (IOD) were noted. The data were analysed using SPSS software. The most frequently present canal was type IV (59.4%) followed by type II (40.6%). Mean MB roots' length for canals exhibiting type IV was 9.26 ± 0.21 mm and of those exhibiting type II was 12.8 ± 0.42 mm. Statistically significant relationship was found between MB root length and canal type. Mean IOD for type II and type IV canals was 2.4 ± 0.47 and 3.8 ± 0.21 mm, respectively. Statistically significant relationship was found between IOD and canal type. Length of MB root and IOD had a significant association with canal type present in MFM. This knowledge can enhance clinicians' understanding of canal morphology which can increase predictability and success rate of endodontic treatment.

Evaluation of mesiobuccal root canal morphology and interorifice distance in maxillary first molar teeth: a CBCT study on Southeast Anatolian population

Aims: The aim of this study was to evaluate the mesiobuccal root canal morphologies and interorifice distances of maxillary first molars using cone-beam computed tomography (CBCT). 
 Methods: CBCT images of 477 patients who had undergone CBCT for various reasons were examined and 654 maxillary first molars were included in the study according to the study criteria. 
 Results: The most common canal configuration observed in mesiobuccal roots was type II (p < 0.05). The median interorifice distance was 2.28 mm in roots with type II canal configuration, while it was measured as 2.55 mm in roots with type IV canals, and a significant difference was found depending on the presence of canal in the apical third of the root (p < 0.001). The median interorifice distance was found to be 2.58 mm in males and 2.34 mm in females, and a significant difference was detected (p < 0.001). 
 Conclusion: Various canal variations can be observed in the mesiobuccal roots of maxillary first molars, and the length of interorifice distance can predict the canal type. This information can increase the success rate of endodontic treatment.

Analysis of apical third root canal morphology of the palatal root of maxillary first molar and its proximity to maxillary sinus: A cone-beam computed tomographic study

ABSTRACT Aims: The aim of this study was to assess the angulation of the apical exit from radiographic apex of palatal root of maxillary first molar, to measure the distance between radiographic apex and apical exit of palatal root of maxillary first molar and to measure the distance of apical exit of palatal root of maxillary first molar from maxillary sinus floor. Materials and Methods: A total of 118 untreated, well-developed maxillary first molars were selected on cone-beam computed tomography scans. Data were collected and viewed by invivo5 software. Descriptive statistical analysis was given as mean value. Results: Radiographic apex and apical exit did not coincide in the large number of samples. The palatal root of maxillary first molar was found to be in direct contact with the floor of maxillary sinus in maximum samples. Conclusion: Apical exit does not coincide with the radiographic apex in all the cases. The distance between radiographic apex and apical foramina or apical exit ranges from 0 to 1.43 mm. The apical exit or apical foramina are in direct contact with maxillary sinus floor in 75% cases.

Relationship of Maxillary Sinus and Maxillary First Molar Root Using Cone Beam Computed Tomography

Background: Cone beam CT (CBCT) is an advancement of conventional CT that uses a divergent pyramidal or conical X-ray beam for imaging the craniofacial complex. Studies on the maxillary sinus and its relationship with the roots present within its close proximity are mostly based on computed tomography imaging and rarely being based on cone-beam computed tomography (CBCT). This study aims to determine the relationship of maxillary sinus and the mesiobuccal root of maxillary first molar using cone beam computed tomography (CBCT).
 Methods: The study was conducted in Armed Forces Institute of Dentistry (AFID) from Sept, 2019 to Feb, 2020. 142 CBCTs were studied in the duration of six months. The distance between the maxillary mesiobuccal root and floor of maxillary sinus was measured using the built in software. The data collected was analyzed using SPSS 23. p-value of <0.005 was considered significant. 
 Results: The mean distance was -0.85 mm ± 2.56 on left side and -0.74mm ± 2.40 on right side. There was no significant difference between left and right side. The correlation between age and left and right-side measurements was statistically significant, p-value 0.000.
 Conclusion: The relationship of maxillary sinus and the mesiobuccal root of maxillary first molar is significant. The study shows that in dentate healthy patients, the maxillary mesiobuccal molar root is nearly in contact with the sinus floor. These findings lead to the conclusion that performing surgical procedures in maxillary molar region may invariably lead to sinus perforation if one is not care full.
 Keywords: Cone beam computerized tomography, Dental implant, Maxillary sinus, Molar

Shaping Ability of F6 SkyTaper®, Hyflex® EDM One File, and One Curve®: A Micro-computed Tomographic Evaluation in Curved Root Canals.

The present study aimed to compare the shaping ability of the F6 SkyTaper® (F6S), HyFlex® EDM OneFile (HEDM), and One Curve® (OC) nickel-titanium single-file instruments using micro-computed tomography. Fifty-two mesiobuccal roots of maxillary first molars, with a degree of curvature between 20° and 42°, were randomised into three experimental groups (n=15 per group): F6S, HEDM, and OC, and a non-instrumented control group (n=7). All specimens were scanned by micro-computed tomography before and after instrumentation. The following parameters were evaluated: preparation time, volume of dentine removed, cutting efficiency, unshaped surfaces, and canal transportation. Cutting efficiency was analysed using an ANOVA parametric test and Tukey's multiple comparison post hoc test. Other parameters were analysed using a non-parametric Kruskall-Wallis test followed by Dunn's multiple comparison post hoc test. No instrument separation occurred during instrumentation. No significant differences were found between the instrument groups with respect to all the parameters (p>0.05). All the instruments induced morphological changes in the root canal dentine (p<0.05) and tended to increase canal transportation toward the coronal portion of the root canals (p>0.05). All instruments were able to shape curved canals and preserve their original anatomy. Single-file endodontic procedures with these instruments can be used with comparable changes in the root canal shape with minimal transportation. (EEJ-2022-01-06).

Evaluation of Canal Preparation Using One NiTi Instrument with Reciprocating Motion Compared Standard ProTaper File to Gold protaper File (An in vitro study)

The present study compared the shaping efficiency of universal system F2 one file NiTi to one NiTi file gold system with reciprocating motion in curved mesiobuccal roots of maxillary first molars, were randomly divided into two groups, each one 15 roots according to the NiTi system using during shaping the roots, after use of each instrument, the canal was flushed with 5 ml of NaOCL and final rinse with EDTA 17% for 1 minute. Parameter were evaluated: Straighten the curved canals, pre and post canals curvatures images were taken using Standarization technique and analyzed using digital radiography (Digora system), the significant level was set at P&lt;0.05. The result showed that NiTi universal Protaper file produced higher amount and percentage of reduction of canal curvature than gold NiTi file system.

Comparison of Infrazygomatic Crest Dimension Above Mesiobuccal Roots of Maxillary Molars in South Indian Subjects: A Retrospective Cone Beam Computed Tomography Study

Aim and Objective: The aim of the study was to compare the full-depth bone thickness and the cortical bone thickness in the infrazygomatic crest (IZC) region above the mesiobuccal (MB) root of maxillary first molar and second molar and thus find the ideal site for the placement of IZC screw. Materials and Methods: Pretreatment cone-beam computed tomography images of 30 orthodontic patients were collected and IZC bone thickness and cortical bone thickness were measured above the MB root of maxillary first and second molar at an angle of 70° to the molar occlusal plane. Measurements were done on both right and left sides. Independent sample t test was done to compare the bone thickness between the right and left sides and also to compare the bone thickness above the first and the second molar. Results: Mean bone thickness at the IZC region of 5.48 ± 2.2 mm and 7.78 ± 2.35 mm and a cortical bone thickness of 2.24 ± 0.46 mm and 2.13 ± 0.46 mm was obtained above the MB root of maxillary first molar and second molar, respectively. IZC bone thickness was significantly higher above the second molar than above the first molar ( P &lt; .001), whereas there was no significant difference in the cortical bone thickness measured on both the sites ( P = .22). Conclusion: Significantly higher IZC bone thickness was noted above the MB root of the maxillary second molar, which may ensure better stability and safety of the miniscrew.

Location of the Maxillary Posterior Tooth Apices to the Sinus Floor in an Egyptian Subpopulation Using Cone-beam Computed Tomography.

The aim of this study was to evaluate the location of the apices of the maxillary posterior teeth to the maxillary sinus floor (MSF), the symmetry between both sides and the possible variations between males and females using cone-beam computed tomography (CBCT) in an Egyptian subpopulation. CBCT images were collected from 120 patients (240 second premolars, 480 1st and 2nd molars, 1680 roots). The proximity of roots of maxillary second premolar and 1st and 2nd molars to the floor of the sinus was categorized into three categories: inside the sinus floor (IS), touching the sinus floor (TS) or outside the sinus floor (OS). The correlation of the distance with gender was analyzed as well as for symmetry. Friedman's test was used to compare between different roots and the Dunn's test was used for pair-wise comparisons when Friedman's test was significant. The Mann-Whitney U test was used to compare males and females. The significance level was set at P≤0.05. The highest prevalence of roots outside the sinus was found with second premolar (right and left) followed by palatal roots of right and left second molar. In addition, the highest prevalence of roots inside the sinus was found with mesiobuccal roots of maxillary second molar followed by the palatal root of maxillary first molar. There was no statistically significant difference between males and females or between both sides. Neither gender nor side variations regarding the proximity to the maxillary sinus floor were observed.

Dentine Thickness of Second Mesibuccal Canals in First Maxillary Molars Prepared with Rotary Instruments.

The purpose of this study was to evaluate the thickness of the remaining dentine wall in the danger zone of the second mesiobuccal (MB2) canals using cone-beam computed tomography (CBCT) in maxillary first molars following preparation by means of HERO 642 rotary instruments with different tapers. The study samples included twenty-five mesiobuccal roots of maxillary first molars. A two-step method was employed to prepare the MB2 canals applying HERO 642 instruments: using a 0.02 taper (step 1), and a 0.04 taper (step 2). The roots were scanned before preparation, and after each step. The thickness of the dentine wall was recorded at the CEJ level, as well as 2 mm and 4 mm below the CEJ. The repeated-measures ANOVA in conjunction with the Cochran tests were used to compare the changes in the thickness of the root canal wall. There was no area with dentine thickness of <0.5 mm before preparation. A significant reduction in dentine thickness occurred following the preparation with both 0.02 and 0.04 files at all three levels compared with the pre-instrumentation values (P< 0.05). However, areas with dentine thickness of < 0.5 mm after preparation using 0.04 files were significantly more than those resulting from the application of 0.02 files both at the CEJ and 2 mm-below-CEJ points, but the differences were not significant at the 4mm-below-CEJ level. Within the limitations of the present in vitro study, the use of larger taper instruments in MB2 root canals of maxillary first molars increased the quantity of samples with dentine thickness less than 0.5 millimeter at the coronal level of the root canal. It was concluded that instruments with large tapers, should be used with caution in troughing or preparing such root canals to reduce the risk of strip perforation.

Maxillary First Molars with Two Palatal Root Canals

Understanding the anatomical variations in the roots and root canal systems of a tooth is important for the success of root canal treatment. The palatal roots of the maxillary molars have fewer anatomical variations than the other roots, and fewer variations occur in the first molars than in the second molars. This case report describes two distinct cases of maxillary first molars with two palatal canals. For the root canal treatment of teeth with anatomical variations, it is essential to plan specific treatment strategies using cone-beam computed tomography and to execute them using a dental operating microscope. Knowledge of the anatomical variations in the palatal roots of maxillary first molars will help to increase the success rate of root canal treatments.

Cone beam computed tomography analysis of residual dentin thickness after virtual post placement in the palatal roots of maxillary first molars

Statement of problemIn endodontically treated maxillary first molars, post space preparations in the palatal roots can compromise the residual dentin thickness (RDT) and increase the risk of perforations or root fractures. This can be attributed to the direction of the buccopalatal curvature that cannot be viewed with conventional 2D imaging. PurposeThe purpose of this clinical study was to investigate the RDT of palatal roots following the placement of digital post analogs of different diameters positioned at various distances from the radiographic apex by using cone beam computed tomography (CBCT). Material and methodsA total of 122 deidentified CBCT data sets containing both maxillary permanent first molars were randomly selected from a private radiology practice. Digital parallel-sided post analogs were superimposed onto the CBCT coronal images at distances of 3 mm, 4 mm, and 5 mm from the radiographic apex and at a depth equal to the height of the anatomic crown (1:1 crown/post ratio). Post analogs of 0.9 mm, 1.0 mm, and 1.14 mm in diameter were matched with safety zone analogs representing 1 mm of circumferential RDT. The minimum RDT for each analog was determined and grouped into 3 categories: RDT≤0 mm, 0 mm<RDT<1 mm, and RDT≥1 mm. The statistical significance between post diameters and post depth was analyzed with the Friedman test and Conover post hoc test (α=.05). ResultsSignificant differences in RDT were found at all tested depths and diameters of post analogs (P<.001). Generally, the amount of RDT increased as the post length was reduced. Most teeth (>50.0%) had inadequate or no RDT. The depth of the post (P<.001) had a greater impact on RDT than the post diameter (P>.017). No similarities were found in the RDT between contralateral molars in 86.9% of the images. ConclusionsThe risk of insufficient RDT (<1 mm) after the placement of parallel-sided posts in the palatal roots of maxillary first molars is minimized if the post is inserted to a depth equaling the height of the crown compared with 3, 4, and 5 mm from the radiographic apex. The RDT of the palatal root of a maxillary first molar is not a reliable predictor of the contralateral palatal root RDT in the same patient.

The antimicrobial effect of different ozone protocols applied in severe curved canals contaminated with Enterococcus faecalis: ex vivo study

The aim of this study was to evaluate 3 different irrigation protocols using ozone on monoculture biofilm of Enterococcus faecalis. Fifty disto-buccal roots of maxillary first molars were instrumented up to the size 25.08, sterilized and then incubated with Enterococcus faecalis for 21days for biofilm maturation in the root canal walls. After contamination, the initial collection (S1) was performed and the 50 samples were divided in 3 experimental groups (n = 15) and 1 positive control group (n = 5) as follows: Group1: Ozonated water (40µg/ml); Group2: gaseous ozone (40µg/ml); Group3: Ozonated water (40µg/ml) under continuous ultrasonic irrigation (CUI) and, Group 4: 2.5% sodium hypochlorite (positive control). The final collection (S2) was performed using hedstroem files # 25 by scraping the root canal wall and absorbed paper cone. The collected samples were analyzed by CFU/ml count and qPCR. To compare the effect of irrigation methods and to investigate E. faecalis count data, Kruskal-Wallis and Wilcoxon nonparametric tests were used at p < 05. The values of the differences between the S1 values and the S2 values revealed that the groups did not differ significantly for either E. faecalis CFU count data (p = 0.713) or q-PCR (p = 0.185), however, it is observed that for all groups, the CFU count of E. faecalis decreased over 99%. For the q-PCR assay, the reduction was on the order of 74-95%. Only the NaOCl positive control group presented total elimination of CFU/mL bacterial counting. The ozone protocols assessed were similar in regard to Enterococcus faecalis reduction.

Assessment of the presence of a second mesiobuccal canal in maxillary first molars according to the location of the main mesiobuccal canal-a micro-computed tomographic study.

To investigate the root canal morphology of mesiobuccal (MB) roots in maxillary first molars, and to assess the presence of a second mesiobuccal canal (MB2) according to the location of the main MB canal. A total of 72 extracted permanent maxillary first molars were collected from dental clinics and were scanned with micro-CT and reconstructed three-dimensionally. The root canal systems were recorded according to Vertucci's classification, and the occurrence of accessory canals was also recorded. The root canal dimensions were measured at the coronal (furcation plane), middle, and apical root levels. The long (D) and short (d) diameters as well as the palatal (P) and buccal (B) distances from the center of the first mesiobuccal canal (MB1) to the root surface were measured, and the ratios of D/d and P/B were calculated. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic accuracy of using the ratio of P/B for predicting the presence of an MB2 canal. The best cut-off point was determined according to the sensitivity and specificity. The MB roots most frequently had a type 2-2 root canal with an incidence of 37.5% (27/72), followed by the type 1-1 (23.6%, 17/72) and type 2-1 (16.7%, 12/72) canal forms. Type 1-2 canals were detected only in 5 molars (6.9%), and type 2-1-2 canals were detected in 6 molars (8.3%). The other 5 cases included 1 case of type 1-2-1 canal and 4 cases of triple canals. MB2 canals were detected in 76.4% (55/72) of the total sample teeth. The incidence of accessory canals was 56.9% (41/72). The mean ratio of D/d was generally "greatest to least": coronal level > middle level > apical level for different root levels and MB single > MB1 > MB2 for different canals, which reflected a trend from a flat to a circular cross-sectional shape. ROC curve analysis showed that at the coronal and middle root levels, areas under the ROC curve (AUC) were greater than 0.99 (P < 0.01), and the best cut-off point was 1.58 and 1.55, respectively; at the apical level, the AUC was 0.94 (P < 0.01), and the best cut-off point was 1.77. The MB2 canals may be present in the MB roots of maxillary first molars with a high occurrence rate at various levels, and the P/B ratio of the MB1 is a good index for predicting the presence of an MB2. However, since all the sample teeth were collected from a Chinese population, clinicians have to be cautious while trying to apply the conclusions on teeth of other ethnic populations. By calculating the P/B ratio, an index reflecting the buccal deviation of the MB1, clinicians can predict the presence of an invisible MB2 in cone-beam computed tomography images with inadequate resolution.

Root Canal Morphology of Maxillary First and Second Molars in a Qatari Population: A Cone-Beam Computed Tomography Study

Abstract Objective The purpose of this study was to evaluate the number of roots and canal configuration of maxillary first and second molars in Qatari population. Materials and Methods A total of 544 cone-beam computed tomography (CBCT) records of Qatari patients were included in this study. The CBCT images were reviewed by two endodontists. The age, sex, bilateral symmetry, root number, and canal configuration according to Vertucci were tabulated. Results About 97.5% maxillary first molars had three roots and 2.5% had two roots. Maxillary second molar showed 88.2% three roots, 7.3% two roots, 3.3% single root, and 1.2% four roots. For maxillary first molars, the most common Vertucci classifications for the mesiobuccal root were type IV (2-2, 35.9%) and type II (2-1, 21.1%). For maxillary second molars, the most common Vertucci classifications for the mesiobuccal root were type IV (2-2, 27%), type III (1-2-1, 21.3%), type I (1, 19.6%), and type II (2-1, 18.9%). In maxillary first molar, 53.1% right is different from the left and in maxillary second molars, 60.2% right is different from the left. Conclusions In Qatari population, three roots are common in maxillary molars. Mesiobuccal root of maxillary first molars is predominant with Vertucci type IV (2-2) and type II (2-1). Maxillary second molars showed variable Vertucci classification. High bilateral asymmetry was found in canal configuration of the same individuals that should be considered during root canal treatment of two opposite molars.

Micro-CT evaluation of maxillary first molars: interorifice distances and internal anatomy of the mesiobuccal root.

This study aimed to describe the morphometric relationship of root canal orifices on the pulp floor in the presence/absence of mesiobuccal second canal (MB2) in the maxillary first molars and other aspects of its internal anatomy. Sixty-two maxillary first molars were scanned by micro-CT. The presence of the MB2 canal was verified. The distance between the center points of the MB1, MB2, distobuccal (DB), and palatal (P) canal orifices on the pulp floor were measured (MB1-MB2, MB1-DB, MB2-DB, MB1-P, and DB-P). The MB1-P to DB-P ratio was calculated. The distances between the anatomic apex and the MB1 and MB2 apical foramina were measured. The length of the band-shaped isthmus was also measured. Student's t-test was applied to verify the association between the presence of an MB2 canal, the interorifice distances, and the ratio of the MB1-P to DB-P distance (α = 5%). The MB2 canal was present in 43 roots (69.35%). Statistics showed significant differences when MB2 was present for the largest MB1-P distance (p < 0.05) and higher values for the MB1-P to DB-P ratio (p < 0.05). A band-shaped isthmus was detected in 25.8% of MB roots. The mean distance from the apical foramen to the isthmus floor ranged from 1.74 for MB1 canals to 1.42 for MB2 canals. Canal orifice distances on the pulp floor may predict the presence of MB2 canals. There was a high incidence of isthmus, accessory canals, and apical delta in the critical apical zone in MB roots of maxillary first molars.

Prevalence and morphology of root canal isthmus in human permanent teeth using micro-computed tomography: A systematic review

Introduction: The isthmus is a communication between two or more root canals that contains pulp tissue. Its unpredictable location, variable prevalence, and anatomic complexity often result in challenging debridement. The knowledge of these factors may prove beneficial for successful endodontic treatment. The primary aim of this systematic review was to assess the prevalence and morphology of root canal isthmus (RCI) in human permanent teeth using micro-computed tomography (micro-CT) studies. The secondary aim was to assess the influence of demographic factors such as age, gender, and geographic region on the prevalence and morphology of the isthmus. Materials and Methods: An electronic search was conducted until January 2020. Studies published in the English language using micro-CT for the evaluation of isthmus prevalence and morphology were included. Sixteen articles met the inclusion criteria and were subjected to qualitative synthesis. Results: The prevalence of isthmus in the mesiobuccal root of maxillary first molars ranged from 8.9% to 70.8%, with maximum prevalence in the middle third of the root (49.50%–73%). The mesial root of mandibular molars had a prevalence ranging from 80.6% to 100% on full root analysis and 85%–88.89% in the apical third. Conclusion: The prevalence of RCI was higher in the mesiobuccal roots of maxillary molars and the mesial roots of mandibular molars, extending in the corono-apical direction with a complex and variable morphology. The influence of demographic factors on the prevalence of RCI could not be established clearly.

Evaluation of root and canal morphology of maxillary permanent first molars in an Emirati population; a cone-beam computed tomography study

BackgroundThe aim of this study was to analyze the root and canal morphology of the maxillary permanent first molars in an Emirati population using cone-beam computed tomography (CBCT).MethodsTwo hundred and sixty-one CBCT scans were acquired. The data were extracted and anonymized to remove all patient identifiers. Two observers (an endodontic resident and an endodontist) evaluated all scans on diagnostic quality monitors.ResultsThe prevalence of a second mesiobuccal canal (MB2) was 80.1% in all examined samples. Type II Vertucci classification, was the most common canal configuration (59%) in the mesiobuccal root, followed by Types I (19.9%) and IV (15.3%), while Type III was the least common (5.7%). Types I, II, and IV were significantly more common in the 21–40-year age group (P < 0.001), while Type III was observed significantly more often in the < 20-year age group (P < 0.001). No significant effect of gender on the prevalence of Vertucci classification in the mesiobuccal root of maxillary first molars (P = 0.74) was found. Analysis of bilateral symmetry showed that 80% teeth had perfect bilateral symmetry, whereas 20% were asymmetrical. Type II canal configuration showed the highest prevalence of bilateral symmetry (48.7%), followed by Type I (15%) and Type IV (10%), while Type III showed the least prevalence of symmetry (3%).ConclusionsThis was the first study to analyze the prevalence of MB2 canal in an Emirati population. Our results indicate high prevalence of MB2 (80.1%) and emphasize the importance of using advanced techniques to locate the MB2 canal.