Evaluation of Root and Canal Morphology of Maxillary Permanent First Molars in a North American Population by Cone-beam Computed Tomography

Introduction

The purpose of this study was to evaluate the number of roots and canal morphology of maxillary permanent first molars in a North American population.

Methods

Three hundred seventeen cases with bilateral maxillary first molars were included. All images from cone-beam computed tomography were carefully reviewed by 2 endodontists. Frequency of number of roots, presence of an additional mesiobuccal canal (MB2), and Vertucci canal type for each root were tabulated. Age, gender, and ethnicity differences were calculated with the χ² test. The intra-rater reliability was assessed by using the Cohen kappa statistic.

Results

The fused root rate was 0.9%. The occurrence of 3-rooted maxillary first molars differed between left and right sides (P = .03). MB2 occurrence only showed statistically significant differences among age groups (P = .005). In the mesiobuccal roots, the most common Vertucci classifications of canal types were type IV (2-2, 41.9%), type I (1, 28.3%), and type II (2-1, 26.3%). There was a statistically significant difference in Vertucci classification of canal type among 5 ethnic groups (African American, Asian, Hispanic, Other, and Non-Hispanic white, P < .001).

Conclusions

Cone-beam computed tomography facilitates the identification of root and canal configuration. The information gained about the tooth anatomy and canal morphology before treatment could potentially facilitate root canal therapy.     

Differences on the Root and Root Canal Morphologies between Asian and White Ethnic Groups Analyzed by Cone-beam Computed Tomography

Introduction

Populations from different geographic regions and ethnic backgrounds may present differences in dental morphology. The aim of this study was to compare the differences in root and root canal configurations on Asian and white subpopulations using cone-beam computed tomographic imaging.

Root Canal Shape of Human Permanent Teeth Determined by New Cone-Beam Computed Tomographic Software

IntroductionThe purpose of this study was to determine root canal cross-sectional shapes (RCCSSs) of human permanent teeth using new cone-beam computed tomographic (CBCT) software.MethodsRCCSS was determined on CBCT scans of 1400 teeth (422 patients) as follows:(1) circular,(2) conical/pyramidal,(3) oval/long oval,(4) flat/ribbonlike,(5) 8 shaped,(6) C shaped,(7) calcified,(8) trapezoidal,(9) drop shaped, and(10) other shapes. Root canal shapes were evaluated in the coronal and middle thirds, 2 mm below their beginning, and in the apical third, 1 and 2 mm short of the apical foramen. Categoric variables were described as frequencies and percentages and analyzed using the chi-square test. The level of significance was set at P = .05.ResultsMaxillary anterior teeth and maxillary first and second premolars had a circular RCCSS at 1 and 2 mm from the apical foramen in more than 45% of the cases. The most frequent RCCSS in the buccal canal of maxillary first premolars at 1 mm from the apical foramen was circular (71%) followed by flat/ribbonlike (10%) and oval/long oval (6%). In mesiobuccal roots of maxillary and mandibular first molars at 1 mm from the apical foramen, the circular shape was found in 52% and 49%, respectively.ConclusionsThe RCCSSs in human permanent teeth are variable according to the tooth group and root thirds. The highest frequency of the circular-shaped canal at 1 and 2 mm from the apical foramen was found in maxillary central incisors and mandibular first and second premolars. Oval-shaped canals were detected in practically all tooth groups and root thirds.     

Influence of the Intracanal Material and Metal Artifact Reduction Tool in the Detection of the Second Mesiobuccal Canal in Cone-beam Computed Tomographic Examinations

IntroductionThe aim of this study was to evaluate the influence of different intracanal materials and the metallic artifact reduction (MAR) tool of cone-beam computed tomographic (CBCT) imaging on the detection of the second mesiobuccal (MB2) canal in maxillary first molars.MethodsForty maxillary first molars were selected; half of them had the MB2 canal in the mesiobuccal root confirmed by micro–computed tomographic imaging. All teeth were instrumented, except for the MB2 canal, and filled with gutta-percha, which was passively inserted up to the working length. Each tooth was individually inserted into a dry human skull, and CBCT scans were performed using the OP300 device (Instrumentarium Dental, Tuusula, Finland) with and without the use of the MAR tool. For each scanned tooth, the following intracanal materials were used in the palatal root: gutta-percha, silver palladium, nickel chromium, and cobalt chromium. Five examiners assessed the images for the detection of the MB2 canal using a 5-point scale. The weighted kappa test was applied to evaluate intra- and interexaminer reproducibility. The diagnostic values (sensitivity, specificity, and area under the receiver operating characteristic curve) were calculated in the different groups and compared using 2-way analysis of variance and the Tukey post hoc test.ResultsThe intra- and interobserver agreement ranges for the different conditions were studied. The diagnostic values were not significantly different (P > .05) regardless of the intracanal material and the use of the MAR tool.ConclusionsThe presence of different intracanal materials and MAR activation does not influence CBCT-based detection of MB2 canals.     

A Cone-beam Computed Tomographic Study of Root and Canal Morphology of Maxillary First and Second Permanent Molars in a Thai Population

Introduction

Understanding tooth anatomy is crucial for effective endodontic treatment. This study investigated the roots and root canal morphology of maxillary first and second permanent molars in a Thai population using cone-beam computed tomographic (CBCT) imaging.

CBCT法研究上颌第一磨牙根管形态

目的：探讨应用锥形束CT研究上颌第一磨牙牙根及根管形态的价值。方法选取70例患者83颗上颌第一磨牙的锥形束CT（cone beam computed tomogaphy,CBCT）影像,分析其牙根数目、根管数目及根管系统的解剖结构。参照Vertucci分类法对根管形态进行分类,统计近中颊根第二根管（the seconal mesiobuual canal, MB2）率。结果83颗上颌第一磨牙均为3个独立牙根,其中MB2的发生率为38.6%,近中颊根根管VertucciⅠ型（1?1）、Ⅳ型（2?2型）、Ⅱ型（2?1）、Ⅲ型（1?2?1）所占百分比分别为61.4%、18.1%、15.7%和4.8%。结论上颌第一磨牙根管系统复杂,CBCT影像可反映真实根管形态,为根管治疗提供参考。     

Endodontic management of a maxillary first molar with eight root canal systems evaluated using cone-beam computed tomography scanning: a case report

Introduction

Root canal treatment of maxillary molars presenting with complex root canal configurations can be diagnostically and technically challenging.

Methods

Nonsurgical endodontic therapy of a left maxillary first molar with three roots and eight root canals was successfully performed. This unusual morphology was diagnosed using a dental operating microscope (DOM) and confirmed with the help of cone-beam computed tomography (CBCT) images.

Results

CBCT axial images showed that both the mesiobuccal and distobuccal root contained a Sert and Bayirli type XV canal, whereas the palatal root showed a Vertucci type II canal configuration.

Conclusions

The use of a DOM and CBCT imaging in endodontically challenging cases can facilitate a better understanding of the complex root canal anatomy, which ultimately enables the clinician to explore the root canal system and clean, shape, and obturate it more efficiently.     

Three Root Canals in the Mesiobuccal Root of Maxillary Molars: Case Reports and Literature Review

Introduction

The knowledge of root canal anatomy is essential to ensure a successful outcome of surgical and nonsurgical root canal treatment. The aims of this article were to present 2 cases of maxillary molars with 3 mesiobuccal root canals and to review the available literature on this anatomic variation.

Methods

The first case described a nonsurgical root canal treatment of tooth #16 in a 29-year-old man with the aid of a dental operating microscope. In the second case, an extracted maxillary right first molar was scanned by a micro–computed tomographic system and reconstructed 3-dimensionally using modeling software.

Results

In both cases, the mesiobuccal root had 3 canals (type 3-2 in case I and type 3-3 in case II), whereas the distobuccal and palatal roots had a single canal. The literature review showed that the overall incidence of 3-canaled mesiobuccal roots in maxillary molars ranged from 1.3%–2.4% and that the most common root canal configuration was type 3-2.

Conclusions

Clinicians should always anticipate the presence of extra canals in maxillary molars and use all the available tools to locate and treat these.     

A cone-beam computed tomography study of root canal morphology of maxillary and mandibular premolars in a Turkish population

Aim. The aim of this study was to evaluate the root canal number and configuration of maxillary and mandibular premolar teeth by gender, intervals for decades, tooth position and unilateral or bilateral occurrence in a Turkish population using Cone Beam Computed Tomography(CBCT) scanning. Methodology. CBCT images of 5496 maxillary and mandibular premolars from 849 patients were evaluated. The following was evaluated in all the images: numbers of roots and root canals, the morphology of the root canal configuration according to the Vertucci classification, male–female differences in the tooth position and male–female differences in unilateral or bilateral occurrence. The reliability data were analyzed with a chi-square test. Results. The most prevalent root canal frequency was the two canals (86.2%) and type IV (76.9%) configuration for maxillary first premolar, one canal (59.7%) and type I (54.5%) canal configuration for second premolar. The incidence of one canal was higher in females and the occurrence of two or three canals was more common in males. The incidence of one canal was higher on the left side of maxillary premolars and the incidence of two canals was higher on the right side. Most mandibular first (93.5%) and second (98.5%) premolars had one canal. In general, females had one root canal of the mandibular premolar, whereas males had two or three canals. The type I configuration was most common and the incidence was higher on the right side. There were some differences found in the frequency distribution of the number of root canals and configuration of maxillary and mandibular premolar teeth according to intervals for decades. Conclusion. CBCT scanning provides comprehensive information about the root canal morphology of maxillary and mandibular premolar teeth. These data may help clinicians in root canal treatment of premolar teeth.     

Evaluation of Root Canal Configuration of Maxillary Molars in a Brazilian Population Using Cone-beam Computed Tomographic Imaging: An In Vivo Study

Introduction

The aim of this study was to analyze and characterize root canal morphology of maxillary molars of the Brazilian population using cone-beam computed tomographic (CBCT) imaging.

Methods

Patients referred for a CBCT radiographic examination for accurate diagnosis and treatment planning were enrolled in the study. A total of 620 healthy, untreated, fully developed maxillary first and second molars were included (314 first molars and 306 second molars). The following observations were recorded: (1) number of roots and their morphology, (2) number of canals per root, (3) fused roots, and (4) primary variations in the morphology of the root canal systems.

Results

First and second molars showed a higher prevalence of 3 separate roots, mesiobuccal, distobuccal, and palatal, with 1 canal in each root (52.87% and 45.09%, respectively). Two canals in the mesiobuccal roots represented 42.63% of teeth, whereas mesiobuccal roots of second molars presented 2 canals in 34.32%. The most common anatomic variation in the maxillary first molar was related to the root canal configuration of the mesiobuccal root, whereas the root canal system of the maxillary second molar teeth showed more anatomic variables.

Conclusions

Mesiobuccal roots of maxillary molar teeth had more variation in their canal system than the distobuccal or palatal roots. The root canal configuration of the maxillary second molars was more variable than the first molars in a Brazilian population. CBCT imaging is a clinically useful tool for endodontic diagnosis and treatment planning.     

上颌第二磨牙根管解剖形态的初步研究

目的: 利用透明牙技术和锥形束CT(cone-beam computed tomography, CBCT)体层扫描技术对上颌第二磨牙根管解剖形态进行研究, 比较CBCT对根管形态的识别与透明牙有无一致性。方法: 对50颗离体牙进行CBCT扫描, 数据导入用计算机软件, 根据Vertucci根管分型, 记录每颗离体牙每个牙根的根管分型。用改良根管染色技术对离体牙进行透明牙制作, 根据Vertucci分类, 将离体牙按每个牙根进行根管类型统计。采用SPSS17.0软件包对所得数据进行统计学处理。结果: 经过对透明牙的观察, 上颌第二磨牙远中颊根和腭根根管形态以Ⅰ型(1-1)为主, 发现新的根管分型(3-2-2)。近颊根的变异比较复杂, 主要以Ⅰ型居多(54.4%), Ⅱ型(2-1)、Ⅳ型(2-2)、Ⅴ型(1-2)和Ⅵ型(2-1-2)均有发生。近颊第二根管发生率为41.3%;经一致性检验, CBCT与透明牙在根管分型上具有一致性(P<0.001)。结论: 上颌第二磨牙根管解剖形态复杂, 尤其近颊根根管类型多变。CBCT与透明牙对根管的识别具有一致性, 其提供的三维影像技术对临床工作具有指导意义。     

A study of the distobuccal root canal orifice of the maxillary second molars in Chinese individuals evaluated by cone-beam computed tomography

As is commonly understood, the root canal morphology of the maxillary molars is usually complex and variable. It is sometimes difficult to detect the distobuccal root canal orifice of a maxillary second molar with root canal treatment. No literature related to the distobuccal root canals of the maxillary second molars has been published.

Objective

To investigate the position of the distobuccal root canal orifice of the maxillary second molars in a Chinese population using cone-beam computed tomography (CBCT).

Material and methods

In total, 816 maxillary second molars from 408 patients were selected from a Chinese population and scanned using CBCT. The following information was recorded: (1) the number of root canals per tooth, (2) the distance between the mesiobuccal and distobuccal root canal orifice (DM), (3) the distance between the palatal and distobuccal root canal orifice (DP), (4) the angle formed by the mesiobuccal, distobuccal and palatal root canal orifices (∠ PDM). DM, DP and ∠ PDM of the teeth with three or four root canals were analyzed and evaluated.

Results

In total, 763 (93.51%) of 816 maxillary second molars had three or four root canals. The distance between the mesiobuccal and distobuccal orifice was 0.7 to 4.8 mm. 621 (81.39%) of 763 teeth were distributed within 1.5-3.0 mm. The distance between the palatal and distobuccal orifice ranged from 0.8 mm to 6.7 mm; 585 (76.67%) and were distributed within 3.0-5.0 mm. The angle (∠ PDM) ranged from 69. 4º to 174.7º in 708 samples (92.80%), the angle ranged from 90º to 140º.

Conclusions

The position of the distobuccal root canal orifice of the maxillary second molars with 3 or 4 root canals in a Chinese population was complex and variable. Clinicians should have a thorough knowledge of the anatomy of the maxillary second molars.     

Analisi della morfologia radicolare e canalare di molari superiori ed inferiori in una popolazione Caucasica: studio in vivo alla CBCT

AimTo investigate the root and canal morphology of maxillary and mandibular permanent molar teeth in a Caucasian population by using Cone Beam Computed Tomography (CBCT).MethodsA total of 596 permanent molars were included. The number of roots, the number of canals per root and the root canal configurations according to the method of Vertucci were recorded.ResultsAlmost all of maxillary first molars (95.7%) had three separate roots; however, 40.3% of mesiobuccal roots had two canals (MB2). Of 157 maxillary second molars, 88.5% had three roots. Among the mesiobuccal roots, 15.1% had two canals. The majority of mandibular molars (100% of first molars, 89.4% of second molars) had two separate roots. Most distal roots had a simple type I configuration, whereas mesial roots had more complex canal systems, with more than one canal.ConclusionsCBCT is an efficient method of studying root canal systems.     

A retrospective study of initial root canal treatment failure in maxillary premolars via using cone-beam computed tomography

BackgroundThis case-series study examined canal morphology and common factors for endodontic failure in maxillary first and second premolars that were referred for retreatment owing to clinical symptoms or radiographic signs.MethodsRecords were retrospectively searched using Current Dental Terminology codes to identify maxillary first and second premolars with endodontic failure. Periapical and cone-beam computed tomographic images were examined to determine Vertucci classifications and suspected factors related to treatment failure.ResultsA total of 235 teeth from 213 patients were included for evaluation. The following Vertucci classification of canal configurations were observed for maxillary first and second premolars: type I (1-1) (4.6% and 32.0%, respectively), type II (2-1) (15.9% and 27.9%, respectively), type III (2-2) (76.1% and 36.1%, respectively), type IV (1-2) (0% and 2%, respectively), and type V (3) (3.4% and 2%, respectively). More treatment failures were noticed in maxillary second premolars than first premolars and in females than in males. The 4 most common factors related to failure were inadequate filling, restorative failure, vertical root fracture, and missed canals. Missed canals were more frequently identified in maxillary second premolars (21.8%) than first premolars (11.4%) (P = .044).ConclusionsMultiple factors are associated with primary root canal treatment failures in maxillary premolars. Variations in canal morphology appear to be underappreciated in maxillary second premolars.Practical ImplicationsMaxillary second premolars have more complicated canal configurations than first premolars. Besides adequate filling, clinicians should give extra attention to anatomic variability in second premolars owing to higher failure incidence.     

上颌前磨牙牙根及根管形态的锥形束CT研究

目的研究上颌前磨牙牙根形态、三根管的发生率和根管解剖形态,为临床诊疗提供参考。方法选取珠海市口腔医院412名患者,共779颗上颌第一前磨牙,728颗上颌第二前磨牙的锥形束CT(cone-beam computed tomography,CBCT)扫描数据,分析上颌前磨牙的牙根及根管形态,三根管的发生率、双侧对称性、根管分叉位置等。结果上颌第一前磨牙三根管发生率为1.8%,上颌第二前磨牙三根管发生率为0.3%,上颌第一前磨牙三根管发生率显著高于上颌第二前磨牙(X^2=8.304,P=0.004)。上颌第一前磨牙三根管对称率为27.3%,上颌第二前磨牙无对称三根管结构出现。上颌前磨牙解剖形态可为单根、双牙根或三牙根,其内部根管形态复杂,存在七种Vertucci根管类型,上颌第一前磨牙以VertucciⅣ型为主,上颌第二前磨牙则以VertucciⅠ型常见。三根管上颌前磨牙的根管分叉位置多见于根中或根上1/3,16颗三根管上颌前磨牙都具有三个独立的根尖孔。结论上颌前磨牙根管形态复杂多变,CBCT对发现变异和额外根管具有重要辅助作用。     

Proximity of Vascular Bone Channel in the Lateral Sinus Wall to Root Apices of Maxillary First Molars: A Cone-beam Computed Tomographic Analysis

IntroductionApical surgery is frequently indicated in maxillary first molars. Occasionally, a vascular anastomosis in the lateral maxillary sinus wall can be observed during surgery. The aim of this study was to examine the distance between the vascular bone channel (VBC) and the root apices of maxillary first molars using cone-beam computed tomographic imaging.MethodsCone-beam computed tomographic images of 104 maxillary first molars were oriented in the coronal plane to evaluate the distance between the roots and the VBC. The measurements were only recorded in relation to the buccal roots. In addition, demographic parameters and further measurements such as the diameter of the VBC and the proximity to the periapical pathology were evaluated.ResultsA total of 210 VBCs were assessed. The mean distance from the VBC to the apices of the buccal roots of the maxillary first molars was 6.18 mm ± 3.84 mm. The VBC was mostly located intrasinusally (74.3%) and only rarely superficially (0.5%). The diameter of the VBC was on average 0.88 ± 0.32 mm.ConclusionsIn this study, the VBC was usually found closer to the mesiobuccal than to the distobuccal root apex. During preparation of the access window, the existence of the VBC should be kept in mind because the mesiobuccal roots of maxillary first molars undergo apical surgery to the buccally positioned roots only.     

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.     

Use of Cone-beam Computed Tomography to Evaluate Root Canal Morphology and Locate Root Canal Orifices of Maxillary Second Premolars in a Chinese Subpopulation

Introduction

The aim of this study was to investigate root canal morphology and locate root canal orifices of maxillary second premolars in a Chinese subpopulation using cone-beam computed tomographic imaging.

Methods

A total of 392 cone-beam computed tomographic images of maxillary second premolars were obtained from 238 patients who required a preoperative assessment for implant surgery or orthodontic treatment. The number of roots and root canals and root canal configuration were investigated and categorized using Vertucci's criteria. The distance between the root canal orifice and the anatomic apex and the distance between root canal orifices in those teeth with 2 root canals were measured and evaluated. The Fisher exact test was used to analyze the correlation between the number of roots and sex.

Results

Among the 392 teeth, 86.5% (n = 339) had 1 root; 45.4% (n = 178) of the teeth had 1 root canal, and 54.3% (n = 213) had 2 root canals that ranged from type II–type V. The majority of teeth with 2 root canals showed a type IV canal configuration (n = 79, 20.2%) followed by type II (n = 64, 16.3%), type III (n = 45, 11.4%), and type V (n = 25, 6.4%). Only 1 tooth had 3 root canals. No significant difference was found between the number of roots and sex (P > .05). Among the 213 teeth with 2 root canals, the most frequent distribution of the distance between the root canal orifice and the anatomic apex was 5–10 mm (n = 157). The distance between the 2 orifices of 189 teeth was 1–4 mm.

Conclusions

The frequency of teeth with 2 root canals was high in maxillary second premolars. The internal morphology of teeth with 2 root canals was variable. This study provided useful information about the root canal morphology of maxillary second premolars in a Chinese subpopulation.     

Prevalence of Second Mesiobuccal Canals in Maxillary First Molars Detected Using Cone-beam Computed Tomography,Direct Occlusal Access,and Coronal Plane Grinding

Introduction

The purpose of this study was to determine the prevalence of the second mesiobuccal canal (MB2) in 100 maxillary first molars using 3 independent methods and a combination method.

Anatomic Analysis of Palatal Roots of Maxillary Molars Using Micro–computed Tomography

IntroductionThe morphology of the palatal root of maxillary first and second molars was analyzed and compared using micro–computed tomographic scanning.MethodsForty-seven extracted maxillary molars were scanned with a micro–computed tomographic device to analyze the palatal radicular dentin dimensions, canal working width, root length, canal curvature, lateral canals, and apical constriction anatomy. Quantitative data were analyzed with mean and standard deviation for first and second molars, respectively. Comparison was made between first and second molars using an unpaired t test.ResultsThe palatal root of maxillary first molars was found to have statistically significantly thinner dentin than second molars on the palatal aspect of the root 8–11 mm from the apex, correlating to the coronal and middle thirds of the root. First molar palatal roots also had a statistically significantly wider canal mesiodistally than second molars at 13–15 mm from the apex, correlating approximately to the level of the cementoenamel junction and pulpal floor. Significant canal curvature was present. These findings suggest the need for conservative coronal flaring and instrumentation.ConclusionsThe absence of an apical constriction in 76.6% of the specimens highlights the importance of creating an apical seat through instrumentation to maintain obturation materials. A minimum master apical file size of 40 is recommended based on preoperative working widths in the apical 0.5–1.0 mm. A root-end resection of 3.5 mm would remove a greater majority of lateral canals.