Interorifice Distance Research Articles

Comprehensive Analysis of Mandibular First Molar Root and Canal Morphology in Saudi Patients Using Cone Beam Computed Tomography (CBCT).

BACKGROUND The goal of conventional endodontic therapy is to clean the root canal system thoroughly, restore tooth function, and prevent re-infection. Success depends on understanding root canal morphology, resolving apical periodontitis, and using proper techniques. Studies highlight variations in root canal anatomy, with cone-beam computed tomography (CBCT) being crucial for accurate diagnosis despite its high cost and limited availability. MATERIAL AND METHODS This retrospective study reviewed CBCT images of 1820 (907 male, 913 female) patients aged 18 to 78 years. Analysis included 2081 mandibular first molars for variations in root and canal morphology and right- and left-side symmetry. Inter-orifice distance was measured, along with distance from the cementoenamel junction (CEJ) to the level of canal bifurcation. RESULTS In this study, 96.01% of teeth had 2 roots and 3.89% had 3 roots. The percentages of canal configuration were 77.70% for 3 canals, 21.58% for 4 canals, 0.67% for 2 canals, and 0.05% for 1 canal. The inter-orifice distance was 2.07 mm for 2 canals in 1 root and 2.86 mm for 2 canals in separate distal roots. Distance from the CEJ to canal bifurcation varied significantly between 2 canals within 1 distal root (3.35 mm), 2 canals in separate distal roots (1.60 mm), as well as between distal (3.35 mm) and mesial roots (1.10 mm). CONCLUSIONS In mandibular first molars, only 3.89% have additional distolingual roots. Sex and ethnicity showed no influence on number of roots and canals. Distal canals showed a deeper bifurcation and greater inter-orifice distance than did mesial canals.

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.

Evaluation of interorifice distance in permanent mandibular first molar with middle mesial canal in Bengaluru city, Karnataka: A cone-beam computed tomography study

Aim: Analysis of interorifice distance (IOD) between mesiobuccal and mesiolingual canals in the presence of middle mesial canal (MMC) variants in mandibular first permanent molar (MFPM) in an Indian subpopulation. To categorically assess the prevalence of MMC variants considering variation in factors of age and gender. Methods: Analysis of preoperative cone-beam computed tomography (CBCT) images was performed on 256 MFPM. MMCs were classified as fin, confluent, or independent as per the classification given by Pomeranz et al. (1981). Orthogonal slices from pulpal floor to 4 mm below were used to measure mean IOD using the CBCT software tool. Data were subjected to descriptive statistics. The Chi-square test was used for further analysis. Results: The prevalence of independent MMC was 4.7% (n = 12), confluent 14.6% (n = 37), and fin 8.7% (n = 22). The mean IOD measured for fin variant was 3.12 ± 0.512 mm, 3.31 ± 0.402 mm for confluence variant, 3.72 ± 0.493 mm for independent MMC, and 3.36 mm ± 0.579 for two-canal variant. Significant association (P = 0.001) was observed between age, gender, and overall detection of MMC, wherein the presence of fin (8.6%) and confluent (12.9%) configurations was higher (P = 0.003) in individuals ≤40 years. There was increased IOD in females (17.9%) than males (10.3%), for confluent, independent, and two-canal configuration (P = 0.04; =0.01, =0.001). Decreased IOD was observed in individuals >40 years for two-canal configurations (P = 0.05). Conclusion: Preoperative CBCT assessment of MFPM aids in the detection of MMC. According to the results of this study, individuals aged ≤40 years have shown higher prevalence of fin and confluent variants. Increased IOD was seen in females for confluent, independent, and two-canal configurations. Decreased IOD was seen in individuals aged >40 years having two-canal configuration. Thus, root canal complexities vary with age and gender, and should be taken into consideration before endodontic treatment.

3D geometric analysis of second mesiobuccal canal in permanent maxillary first molar tooth.

Cone-beam computed tomography scans exhibiting a second mesiobuccal (MB2) canal were examined. The vertical distance of the MB2 orifice from the pulp floor (depth), inter-orifice distance (IOD) of MB2 from mesiobuccal (MB) and palatal (P) orifices, the horizontal distance of the MB2 orifice from the line joining MB-P orifices [mesial deviation (MD)] and root canal configuration (RCC) were evaluated on 330 scans. The Student's t-test, ANOVA, Spearman's correlation and linear regression analysis were applied. The MB2 depth was 1.69 ± 0.86 mm. IOD (MB-MB2, MB2-P) was 2.18 ± 0.58 mm and 4.63 ± 1.06 mm, respectively. MD was 1.02 ± 0.37 mm. The predominant RCC was Vertucci's type II (75.5%). No correlation of depth with IOD of MB-MB2 (rho=0.0367, p=0.506) was observed. Significant correlation of depth with IOD of MB2-P (rho=0.696, p < 0.001) and MD (rho=0.174, p=0.001) was established. No association of depth with age and IOD (MB-MB2) was observed on linear regression analysis. However, a significant positive association was established with IOD (MB2-P) (p < 0.001) and MD (p=0.001).

Radiographic analysis of interorifice distance and canal configuration in mesial roots of mandibular first molars

Introduction: The Middle Mesial Canal (MMC) is an additional root canal that can be present in the mandibular molars of some patients with high chances of being missed. The aim of this study is to determine the inter orifice distance between Messiobuccal (MB) and Mesiolingual (ML) canal orifice and its association with the presence or absence of MMC using CBCT to help the operator clinically in identifying the presence of MMC. Methods: 50 CBCT samples consisting of 100 permanent mandibular first molar teeth were analysed. The distance between the mesiobuccal and mesiolingual orifice was recorded. Statistical Analysis such Independent T test and Pearson correlation were used to determine the association between MB and ML interorifice distance and presence of MMC and variation in the prevalence of MMC among male and female and different age groups. Results: The mean distance between MB and ML canal orifice was 3.19 ± 0.42mm, in the presence and absence of MMC the mean distance was 3.66±0.24mm and 3.07±0.38 mm respectively. The mean inter orifice distance in males was 3.29 ± 0.38 mm and in females was 3.08 ± 0.45 mm.

Root and canal-specific features of maxillary first molars with fused roots

Background/Aim. Maxillary first molars are one of the most challenging teeth for endodontic therapy. There are certain disparities in the number of roots and canals and canal interrelationships within the same root, particularly those with fused roots. The aim of the study was to assess ex vivo features of roots, root canals, and canal walls in maxillary first molars with fused roots. Methods. Out of the total of 366 maxillary first molars, 64 extracted maxillary first molars with fused roots were included in the study using cone-beam computed tomographic and microscopic examining. Tooth dimensions at the level of pulp chamber floor, number, location and distance between orifices, number and canal morphology, canal wall thickness, and features of apical foramina were examined and measured. Results. The incidence of maxillary first molars with root fusion was 17.5%, of which 60.0% was palatal fused to distobuccal root. At the level of the pulp chamber floor, the bucco-palatal dimension was significantly larger at 10.4 mm than M-D with 7.0 mm. Four canal orifices were detected in 65.6%, with the shortest distance of 1.95 mm between MB1 and MB2. In fused roots, two or three canals most frequently correlated strongly with the number of major apical foramina. No fusion of canals was found in fused roots. The thinnest canal wall in the mesiobuccal and distobuccal fused root was mesial with 1.25 mm, and distal with 1.31 mm, while for the palatal root, the thinnest was the palatal wall with 1.97 mm. Two or three large apex foramina were registered with a significant correlation with the number of canals in the fused root. Conclusion. The most frequent type of fusion was between the palatal and distobuccal roots. Bucco-palatal dimension at the level of the pulp chamber floor was significantly larger than the mesiodistal, with the shortest inter-orifice distance between the MB1 and MB2 orifice. The number of canals was either two or three, coinciding with the number of major apical foramina. There was no fusion of the canals in fused roots. The thinnest canal wall was either mesial or distal.

Abstract 11516: Quantification of Regurgitation Through Dual Orifices: Pulsatile in Vitro Analysis with Echocardiography and MRI Assessment

Introduction: Proximal Isovelocity Surface Area (PISA) measurement is widely accepted to quantify mitral regurgitant volume (RVol), but flow convergence (FC) zones are complicated with dual orifices, seen with mitral clipping. This study seeks to investigate how flow through one orifice affects PISA measurement across the other to better quantify RVol in dual orifice conditions. Methods: 3D-printed dual circular orifice models with varying relative areas were integrated into a pulsatile flow phantom simulating left heart flow. One orifice (A) was standardized at 19.6 mm 2 while the other (B) was 1X, 2X, and 3X the area of A in three models. Inter-orifice distance was 5 mm to emulate mitral clipping. Continuous wave doppler echocardiography measured peak velocity and velocity time integral. PISA was performed at four aliasing velocities normalized to peak velocity (V a /V peak ) (10%, 8%, 4%, 2%) to compute RVol with 2D phase contrast MRI as reference. In each model, PISA RVol and percent error was calculated to see how varying the area of B impacts PISA accuracy of A. 4D flow MRI FC data was also collected to visualize the 3D formation of FC zones. Results: Using a high V a /V peak to create distinct FC zones provides a better RVol estimation with PISA, as low V a /V peak will merge the FC zones, overestimating flow across individual orifices. Single factor analysis of variance (ANOVA) of percent error of A across the three models showed no significant difference at high V a /V peak (8%: p=0.80, 10%: p=0.23), but significant difference at low V a /V peak (2%: p=0.010, 4%: p=0.005). High V a /V peak FC zones of orifices are independent from each other; PISA can be measured with standard practices and added together for an accurate total RVol. At low V a /V peak , FC orifice zones overlap with overestimation error increasing with larger B area. This finding suggests that resolving two separate FC zones to minimize flow interference is important for accurate RVol estimate in a dual orifice setting.

CBCT evaluation of root canal morphology and anatomical relationship of root of maxillary second premolar to maxillary sinus in a western Chinese population

BackgroundTo evaluate the root anatomy, root canal morphology and the anatomical relationship between the roots and maxillary sinus of maxillary second premolars by CBCT in a western Chinese population.MethodsA total of 1118 CBCT scans of the maxillary second premolars were collected from West China Hospital of Stomatology, Sichuan University. Information below were measured on axial, coronal and sagittal sections, recorded and evaluated properly: the number of roots and canals, the morphology of canal system classified by Vertucci standard, the inter-orifice distance of canal orifices, the curvature of each canal and the distance from root tip to maxillary sinus floor.ResultsAmong the 1118 teeth, 94.2% (1053) are single-rooted and 55.1% (616) have one canal. Type I (55.1%) is the commonest root canal morphology followed by Type II (31.9%). The mean inter-orifice distance (IOD) for multi-canal teeth ranging from 2.72 ± 0.32 to 3.41 ± 0.11 mm. Of 1622 canals, 38.8% (630) curvature are mesiodistal and 30.9% (501) are straight canals. The distance from root tip to maxillary sinus floor increased with age and the mean distance of single-rooted ones is 2.47 ± 3.45 mm.ConclusionsAll kinds of canal morphology category can be detected in maxillary second premolars. The IOD might be a predictable factor for root canal morphology. Roots of maxillary second premolars are related to maxillary sinus which should be treated carefully.

Assessment of Mesiobuccal Canal Configuration, Prevalence and Inter-Orifice Distance at Different Root Thirds of Maxillary First Molars: A CBCT Study.

AimThe aims of this study were to assess the prevalence and configuration of the second mesiobuccal (MB2) canal in the mesiobuccal MB root of permanent maxillary first molars at different root levels in a Saudi sub-population using cone‑beam computed tomography (CBCT) and to measure the inter-orifice distance between MB & MB2 at the pulpal floor level.Materials and MethodsThis retrospective study was carried out on CBCT images of Saudi patients seen at King Abdul Aziz University. A total of 106 maxillary first molars were evaluated using a specialized software program (iCAT CBCT software). The prevalence of MB2, canal configuration and location of joining (apical-middle-coronal), if present was calculated. Also, the inter-orifice distance between both canals was measured at the level of the pulpal floor. Chi‑square and one-way analysis of variance (ANOVA) were used.ResultsThe MB2 canal was found in 92 (86.8%) maxillary first molar teeth. The MB and MB2 canals were joined in 61 (58%) cases, where the location of joining was 14 (23%), 17 (27%), and 31 (50%) in the coronal, middle, and apical third, respectively. The mean inter-orifice distance between both canals at the level of the pulpal floor was 2.52±0.76 mm.ConclusionThe prevalence of MB2 canal in this Saudi sub-population was high. The prevalence decreased as the root canal approached the apical third. There was no correlation between the average distance and occurrence of canal joining. CBCT is useful in detecting and mapping the mesiobuccal root canal system, with a likelihood of enhancing the quality of root canal treatment.

Mesiobuccal and Palatal Interorifice Distance May Predict the Presence of the Second Mesiobuccal Canal in Maxillary Second Molars with Fused Roots

IntroductionThe aim of this study was to evaluate if the configuration of canal orifices can predict the presence of a second mesiobuccal canal (MB2) in maxillary second molars with fused roots. MethodsMaxillary second molars with fused roots (N = 150) were scanned in a micro–computed tomographic device (pixel size = 9 μm) and evaluated regarding the root fusion type and the incidence of the MB2 canal. The centers of the canal orifices were connected, and the angles formed by the intersection of these lines as well as their distances were measured and statistically compared (1-way analysis of variance). Specimens were then assigned to 2 groups according to the presence (n = 65) or absence (n = 50) of the MB2 canal and compared regarding the angles and interorifice distances using the Welch t test. A binary logistic regression model estimated the association between the interorifice distance, the fusion type, and the presence of the MB2 canal, whereas receiver operating characteristic curve analysis was performed to evaluate the diagnostic abilities of significant variables. The significance level was set at 5%. ResultsThe most common fusion types were 1 and 6, and MB2 canal incidence was 47.3%. No statistical difference was observed in the angles or interorifice distances among teeth with different fusion types (P > .05). Distances from the mesiobuccal (MB) to the distobuccal and palatal (P) canal orifices as well as the MB and P angles were significantly higher in the presence of an MB2 canal (P < .05). A binary logistic regression model revealed that MB-distobuccal and MB-P distances were significant in the presence of an MB2 canal (P < .05). Receiver operating characteristic analysis indicated that MB-P distance had acceptable diagnostic accuracy for the prediction of MB2 canal presence. Sensitivity (specificity) calculated from the MB-P distances of 4.0, 4.5, and 5.0 mm were 89.2% (36.5%), 76.9% (58.4%), and 44.4% (71.4%), respectively. ConclusionsMB-P interorifice distance is a strong predictor of the presence of the MB2 canal in maxillary second molars with fused roots.

Association between the Mesiobuccal Canal Configuration, Interorifice Distance, and the Corresponding Root Length of Permanent Maxillary First Molar Tooth: A Cone-beam Computed Tomographic Study

IntroductionThe aim of this cone-beam computed tomographic study was to evaluate the association between the mesiobuccal root canal configuration (RCC), interorifice distance (IOD), and the corresponding root length of a permanent maxillary first molar tooth. MethodsOne hundred cone-beam computed tomographic scans obtained from the computerized data bank of the institute were studied. The IOD between the first mesiobuccal and second mesiobuccal canal was measured in the axial section where the second mesiobuccal canal was first visualized. The root length was measured from the cementoenamel junction to the root apex in the coronal and sagittal section. The associations of these parameters with the RCC (based on Vertucci’s classification) were evaluated. ResultsThe predominant RCC was observed to be Vertucci type II (89%). The mean root length with this configuration was 11.19 ± 1.35 mm. In type IV RCC, the mean root length was 9.13 ± 0.52 mm. A statistically significant association was established between the root length and RCC (P < .05). In roots with type II and type IV RCC, the mean IOD was 2.58 ± 0.04 mm and 2.62 ± 0.1 mm, respectively. No statistically significant relation was established between the IOD and the type of RCC (P > .05). ConclusionsThe length of the mesiobuccal root is an important anatomic parameter for predicting the type of RCC in the permanent maxillary first molar tooth.

Root canal isthmi and interorifice distance in human permanent teeth of an Indian subpopulation using cone-beam computed tomography: A retrospective cross-sectional study.

Objective:The aim of the study was to evaluate the prevalence of root canal isthmus (RCI) and measure the interorifice distance (IOD) between the root canals. Additionally to correlate IOD with the RCI in human permanent teeth using conebeam computed tomography (CBCT) in an Indian sub-population (Chennai).Materials and Methods:A total of 5881 teeth from 280 CBCT full mouth scans were analyzed. The presence or absence of complete and incomplete RCI of each tooth was identified using the map-reading strategy. IOD was calculated by measuring the distance between the center of each root canal orifice to that of the center of the adjacent orifice at the level of the cementoenamel junction using the axial and sagittal sections. Chi-square analysis and correlation statistics using Spearman's rank-order test was done (P < 0.05).Results:High prevalence of RCI was found in maxillary first premolars, mesial root of mandibular molars, and mesiobuccal root of maxillary first molars, while its prevalence was low in maxillary canines and mandibular premolars and absent in maxillary incisors. RCI was predominantly seen in the cervical and middle third of the root canal in all the teeth evaluated. A weak negative correlation was established between the IOD and RCI for maxillary premolars, whereas a weak positive correlation was seen in maxillary first molars and mandibular second molars.Conclusion:The prevalence of RCI was high in the posterior teeth in comparison to the anterior teeth in the present study. There was no strong correlation between IOD and RCI in all the teeth evaluated.

Prevalence and Configuration of the Second Mesiobuccal Canal in the Permanent Maxillary First Molar in Jordanian Population Sample.

Missing a root canal during endodontic treatment implicates the persistence of microbial infection within the root canal system. This study aims to evaluate the incidence and morphology of the second mesiobuccal canal in the maxillary first molars in the Jordanian population. Consecutive cone-beam computed tomography (CBCT) scans taken at Jordan University Hospital were assessed in this retrospective study. A total of 200 scans that were examined, 111 were included in this study. The scans that were included had to have a full view of the maxilla with at least one permanent maxillary first molar. The following data were collected: the presence of a second mesiobuccal canal, the configuration of the mesiobuccal canals, the status of the apical area and the mesiobuccal inter-orifice distance, if applicable. The prevalence and morphology of the second mesiobuccal canal was determined and its association with biological sex and right or left sidedness was measured using the Chi-Square test. The prevalence of the second mesiobuccal canal in our sample of the Jordanian population was 87%, with the most common canal configuration being Vertucci type II. The average inter-orifice distance between first and second mesiobuccal canals was 1.9 ± 0.4 mm. This retrospective study is the first in Jordan to document the prevalence of the second mesiobuccal canal using CBCT, and it shows that the vast majority of teeth have a second mesiobuccal canal. The proper location and negotiation of this canal is of dire importance for endodontic therapy.

Friction-mediated flow and jamming in a two-dimensional silo with two exit orifices.

We show that the interparticle friction coefficient significantly influences the flow and jamming behavior of granular materials exiting through the orifice of a two-dimensional silo in the presence of another orifice located in its vicinity. The fluctuations emanating from a continuous flow through a larger orifice results in an intermittent flow through the smaller orifice consisting of sequential jamming and flowing events. The mean time duration of jammed and flow events, respectively, increase and decrease monotonically with increasing interparticle friction coefficient. The frequency of unjamming instances (n_{u}), however, shows a nonmonotonic behavior comprising an increase followed by a decrease with increasing friction coefficient. The decrease on either side of the maximum, then, represents a system moving progressively towards a permanently jammed or a permanently flowing state. The overall behavior shows a systematic dependence on the interorifice distance, which determines the strength of the fluctuations reaching the smaller orifice leading to unjamming instances. The probability distributions of jamming and flowing times are nearly similar for different combinations of friction coefficients and interorifice distances studied and, respectively, exhibit exponential and power-law tails.

Inter-orifice distance dependence of flow rate in a quasi-two-dimensional hopper with dual outlets

We have experimentally investigated granular flow through a quasi-two-dimensional hopper with two symmetric outlets on a flat bottom. The relationship between the flow rate and inter-orifice distance, namely the spacing between two outlets, for the whole range of outlets studied, is well described by an empirical equation we have presented. We have also measured the velocity and packing density profiles in the flow of particles above the outlets. We find that the packing density has a small fluctuation with respect to the inter-orifice distance, which may be considered as a constant based on zero order approximation. On the assumption of continuous flow and a constant packing density, we prove that the relation between the flow rate and the inter-orifice distance is mainly attributed to the velocity above each outlet, which is affected by a repulsive interaction between two outlets.

Morphological Characteristics and Classification of Mandibular First Molars Having 2 Distal Roots or Canals: 3-Dimensional Biometric Analysis Using Cone-beam Computed Tomography in a Korean Population

IntroductionThe aim of this study was to determine the morphologic characteristics of mandibular first molars having 2 canals in distal roots. Interorifice distance, buccal bone thickness, and root curvature were evaluated using cone-beam computed tomography images in a Korean population. MethodsIn total, 1958 mandibular first molars were evaluated in axial, coronal, sagittal, and paraxial planes. Distal roots having 2 canals were classified according to their root and canal shapes (2 roots, 2 canals [2R2C]; 1 root, 2 canals with 2 apical foramina [1R2C(2-2)]; and 1 root, 2 canals with 1 apical foramen [1R2C(2-1)]). The distances between orifices and the distance from the apex to the buccal bone plate were measured for each root canal shape (2R2C, 1R2C[2-2], and 1R2C[2-1]). The curvature of distolingual (DL) roots was classified according to severity using 3-dimensional reconstructed images, and the direction of curvature was determined. The relationships of these characteristics to sex and side were evaluated. ResultsThe prevalences of 2R2C, 1R2C(2-2), and 1R2C(2-1) were 25.89%, 10.32%, and 14.15%, respectively. The distances between distobuccal (DB) and DL orifices were 3.77 ± 0.74 mm for 2R2C, 3.02 ± 0.65 mm for 1R2C(2-2), and 2.44 ± 0.64 mm for 1R2C(2-1). The distances from the buccal plate to the DB canal were 3.84 ± 1.35 mm for 2R2C, 5.33 ± 1.41 mm for 1R2C(2-2), and 5.96 ± 1.63 mm for 1R2C(2-1). The distance from the buccal plate to the DL canal was 9.85 ± 1.46 mm for 2R2C, and 8.28 ± 1.50 mm for 1R2C(2-2). All distances differed significantly according to root canal configurations, and all were greater in men than women (P < .05), except for the DB-DL orifice distance in 1R2C(2-2) and the DB to buccal cortical plate distance in all root configurations (P > .05). No significant difference between the left and right sides was found (P > .05). The prevalence of most severely curved DL roots (type III) was 62.92%, and the direction was commonly toward the buccal side (69.03%). ConclusionsThe prevalence of mandibular first molars having 2 canals in distal roots was more than 50% in a Korean population. Interorifice distances between DB and DL canals and distances from the apex to the buccal cortical plate differed according to root and canal numbers and shapes.

Assessment of the Second Mesiobuccal Root Canal in Maxillary First Molars: A Cone-beam Computed Tomographic Study

IntroductionThe purpose of this study was to investigate the incidence and location of the second mesiobuccal (MB2) root canal of the maxillary first molar and the relationship between the presence of an MB2 canal and the distribution of canal orifices on the pulpal floor with the aid of cone-beam computed tomographic (CBCT) technology. MethodsA total of 1008 maxillary first molars (548 patients) were randomly selected and analyzed through CBCT imaging. The association between the incidence of MB2 canals and potential impacting factors including sex, side, age, and the distribution of the main root canal orifices on the pulpal floor was explored. The interorifice distances (ie, the length of a line between the center point of any 2 orifices) at the pulpal floor level were measured using Mimics 10.01 software (ImageWorks, Materialise, Belgium). ResultsThe majority of 3-rooted maxillary first molars showed 2 root canals (85.4%) in the mesiobuccal root. The incidence of MB2 canals had no statistically significant difference between the left and right sides (P > .05) but had a significant association with the patients' sex and age (P < .05). Receiver operating characteristic curve analysis showed a high diagnostic accuracy (the area under the receiver operating characteristic curve = 0.92) of using the distance ratio of the interorifice distance between the main mesiobuccal and the palatal root canal orifices to the interorifice distance between the distobuccal and the palatal root canal orifices to predict the presence of an MB2 canal. A larger distance ratio (>1.26) indicated a highly probable existence of an MB2 canal. In this study, no molar presented an MB2 canal with a distance ratio of less than 1.16, whereas all molars with a ratio greater than 1.37 presented an MB2 canal without exception. A Bland-Altman scatterplot showed great agreement between the distances of the main mesiobuccal and the distobuccal canal orifices and the second mesiobuccal and the distobuccal canal orifices. ConclusionsUnderstanding the incidence of MB2 canals and the distribution pattern of canal orifices on the pulpal floor may help clinicians to quickly identify and locate MB2 canals.

Geometric features of second mesiobuccal canal in permanent maxillary first molars: a cone-beam computed tomography study

Background/purposeInadequacy to locate the second mesiobuccal canal (MB2) canal leads to the highest probability of endodontic failure in permanent maxillary first molars (PMFMs) and still remains a constant challenge for many clinicians. The aim of this study was to characterize the geometrical features between MB2 and other orifices of examined PMFMs using cone-beam computed tomography images. Materials and methodsA total of 108 teeth qualified in the cone-beam computed tomography image archives were enrolled in the present study. The intersecting point (T) was determined as the perpendicular line (h, altitude of triangle) projected from the vertex of the MB2 canal orifice to mesiobuccal canal orifice-palatal canal orifice line (MB1-P). We measured the geometric features of PMFMs with the MB2 canal, including the interorifice distances, area, altitude, and the ratio between the canal orifices. ResultsThe average interorifice distance was found to be 1.91±0.59 mm for MB1-MB2, 5.73±0.66 mm for MB1-P, and 4.11±0.79 mm for MB2-P, with significant gender difference for MB1-MB2 distance. For the MB1-T distance, a significant difference was found between genders (P=0.02), with males averaging 1.78±0.07 mm, and females 1.48±0.11 mm. For the MB1-P distance, the majorities of both genders were found in the 20–40% cut-off. A portion of the males exhibited a tendency towards the 40–80% cut-off, while females shifted in the reverse direction towards the 0–20% cut-off. ConclusionIn clinical scenarios, these anatomical characteristics of the root canals system could be beneficial to locating the MB2 canal.

Spontaneous jamming and unjamming in a hopper with multiple exit orifices.

We show that the flow of granular material inside a two-dimensional flat bottomed hopper is altered significantly by having more than one exit orifice. For hoppers with small orifice widths, intermittent flow through one orifice enables the resumption of flow through the adjacent jammed orifice, thus displaying a sequence of jamming and unjamming events. Using discrete element simulations, we show that the total amount of granular material (i.e., avalanche size) emanating from all the orifices combined can be enhanced by about an order of magnitude difference by simply adjusting the interorifice distance. The unjamming is driven primarily by fluctuations alone when the interorifice distance is large, but when the orifices are brought close enough, the fluctuations along with the mean flow cause the flow to unjam.

Prevalence of Three-Rooted Mandibular First Molars among Indians Using SCT.

Undetected extra roots or root canals are a major reason for failure of endodontic treatment. Failure to recognize an extra distolingual (DL) root in mandibular first molar may lead to incomplete debridement of the root canal system and eventually treatment failure. Therefore, it is crucial that atypical anatomy is identified before and during dental treatment. Spiral computed tomography (SCT) images can show 3D images, and therefore much detail can be used when traditional methods prevent adequate endodontic treatment. The overall incidence of DL roots on the mandibular first molars was 6.40% for all patients and 5.00% for all teeth, respectively. The occurrence of DL roots on the right side and on the left side showed a statistically significant difference. The bilateral incidence of symmetrical distribution of DL roots was 56.25%. The DL root canal orifice was separated from DB canal orifice by 2.79 ± 0.34 mm, from the MB canal orifice by 4.23 ± 0.81 mm, and from the ML canal orifice by 3.29 ± 0.52 mm. The high prevalence of the DL root in permanent mandibular first molars among the Indian population by using SCT and estimations of the interorifice distance of such teeth might be useful for successful endodontic treatments.