Multipopulation evaluation of the internal morphology of mandibular first premolars from different South American countries. A micro-computed tomography study.

OBJECTIVE: To evaluate and compare several anatomical parameters of mandibular first premolars from individuals from different Latin American countries using micro-computed tomography. DESIGN: Five hundred extracted mandibular first premolars from Brazilian, Argentinian, Chilean, Colombian, and Ecuadorian individuals were scanned using micro-computed tomography (n = 100 teeth/country). Root canal configurations were classified according to established parameters. Analyses also included: canal volume and surface area, structure model index, distances from the apical foramen to the root apex or the cementoenamel junction, major/minor apical canal diameters, canal orifice shape, and prevalence of ramifications. RESULTS: A single root was the most common anatomy in all countries (range, 97%-100%). Vertucci's type-I canal was the most frequent configuration (range, 36%-66%), followed by C-shaped and type-V canals. The oval-shaped canal orifice was the most predominant in all countries (range, 34%-58%), followed by the circular shape (range, 16%-47%). C-shaped canals occurred in all subpopulations (range, 14%-26%), always associated with radicular grooves. Ranges for canal ramifications were as follows: accessory canals, 36%-73%; lateral canals, 4%-12%; and apical delta, 4%-14% of the teeth. Many anatomic parameters differed significantly between countries (P < .05). CONCLUSIONS: Vertucci's types-I and -V, and C-shaped canals were the most prevalent configurations in the subpopulations investigated. Accessory canals and several complex anatomies were found, with some significantly different frequencies between countries.

CBCT and Micro-CT analysis of the mandibular first premolars with C-shaped canal system in a Chinese population author.

OBJECTIVES: The purpose of this study was to survey the prevalence of C-shaped root canal system in mandibular first premolar in Chinese population by reading Cone-beam computed tomography (CBCT) images and to analyze its anatomical characteristics by CBCT and Micro-computed tomography (Micro-CT). METHODS AND MATERIALS: The prevalence and the morphologic features of C-shaped root canal system were evaluated by observing CBCT images of 760 patients (1520 mandibular first premolars). 66 mandibular first premolars with C-shaped root canal system were scanned by Micro-CT. The morphologic features including radicular groove, C-shaped root canal categories in the cross-sections and in the 3D models, accessory and connecting canals, apical foramina and accessory foramina, were analyzed using image software. RESULTS: C-shaped root canal system was identified in 16.9% of mandibular first premolars. The minimum mesial wall thickness most commonly occurred at the lingual site (69.7%). Regarding to the cross-sectional classification, the maximum was C2 (41.5%). In the 3D classification, the most common was S (34.8%). Accessory canals were observed in 36.4% of the samples and occurred mostly in the middle and apical regions. 42.4% samples had 1-3 variable connecting canals, and 40.9% samples had only one apical foramen. CONCLUSIONS: The incidence of C-shaped root canal system in mandibular first premolars was 16.9% in the Chinese population. The anatomy was very complex and variable, mostly distributed in the middle and apical regions of the root canal. The mesial wall of C-shaped canal was extremely thin on the lingual side.

Endodontic Management of Three-rooted Mandibular First Premolar Using Cone-beam Computed Tomography: A Case Report.

The anatomy of the root canal system always affects endodontic treatment outcomes. Mandibular premolar teeth demonstrate extreme variations in root canal morphology. Mandibular first premolars typically exhibit basic single-root and single-canal anatomy. The occurrence of three roots in the mandibular first premolar has not been commonly reported in the literature. This article reported a case of a 26-year-old male with spontaneous pain of the mandibular first premolar representing the presence of an extra canal on the periapical radiograph. Cone-beam computed tomography (CBCT) was used to assess the root canal details which led to the finding of three canals. Further, a periapical bone defect was detected, and finally, the nonsurgical endodontic management of the mandibular first premolar with three canals and three different apical foramina was performed in one session.

Root canal narrowing patterns of mandibular first premolars on panoramic radiographs according to the number of root canals diagnosed on cone beam computed tomographic images.

Understanding the variations in root canal morphology is important for successful endodontic treatment. Mandibular first premolars have a single root in 98% of cases, and multiple root canals are found in approximately 20% of cases. However, the details of these characteristic findings in panoramic radiography and their diagnostic accuracy are unknown. This study aimed to investigate the characteristic radiographic findings of mandibular first premolars possessing multiple root canals and determine the diagnostic accuracy using panoramic radiography. Four radiologists evaluated 347 mandibular first premolars in 186 patients who underwent panoramic radiography and dental cone beam computed tomography (CBCT). Two radiologists confirmed the existence of single or multiple root canals using CBCT. The remaining two radiologists evaluated the imaging findings of the root canal morphology and classified them into two patterns: gradual narrowing and sudden narrowing. In the case of the sudden narrowing pattern, the location of sudden narrowing was also evaluated. A gradual narrowing pattern was observed in 56% of teeth with a single root canal, and a sudden narrowing pattern was observed in 83% of teeth with multiple root canals. When sudden narrowing between the cervical and apical 1/4 of the root canal was used as the diagnostic criterion for multiple root canal teeth, the highest diagnostic performance was observed (sensitivity, 76.1%; specificity, 73.9%). The sudden narrowing between the cervical level and the apical 1/4 level of the root canal is a practical diagnostic criterion for mandibular first premolar with multiple root canals.

A micro-CT analysis of radicular dentine thickness in mandibular first premolars presenting C-shaped root canals: Identification of potential danger zones.

AIM: To describe the radicular dentine thickness in mandibular first premolars presenting C-shaped root canals, to identify the canal walls with less thickness as potential danger zones. In addition, to describe the internal and external anatomical characteristics of these teeth and associate them with the dentine thickness. METHODOLOGY: A total of 70 mandibular first premolars presenting C-shaped root canals were examined. Their internal morphology was analysed using Vertucci's and Fan's criteria, and their external morphology was analysed using the ASUDAS score. Besides, the dentine thickness around the root canals was two/three-dimensionally determined at five root planes and quantified in the distal and the mesial aspects. RESULTS: According to Fan's, ASUDAS, and Vertucci's classifications, the most common canal configurations were category C3, grade 3, and type V, respectively. In Vertucci's type III anatomy, the mesial root wall of the lingual canal showed significantly less dentine thickness than the distal wall in the middle plane (p = .031). Similarly, in Vertucci's type V anatomy, significantly less dentine thickness was observed in the mesial root wall of the buccal and lingual canals in the middle plane (p < .001) and the buccal canal in the middle-apical plane (p = .014) than the distal root wall of these canals. In teeth with ASUDAS grade 3 and 4 scores, significantly less dentine thickness was observed in the mesial in comparison with the distal root wall of these canals. These differences were demonstrated in the middle and middle-apical planes (p < .001) of grade 3 teeth and the middle-apical plane (p < .001) of grade 4 teeth. In these root planes, the Ver1-AS3 and VerV-AS3 combinations presented a 4-times greater risk of presenting walls with a critical dentine thickness of 0.6 mm (odds ratio [OR] = 4, p = .025) than the combinations Ver1-AS2, VerV-AS2, VerV-AS4, and VerIII-AS3. CONCLUSIONS: The root canal system configuration of mandibular first premolars with C-shaped canals showed a wide range of anatomical variations. The lowest dentine thickness was located in the mesial wall of the canals in the middle and apical root thirds of Vertucci's type III and V anatomies and in teeth with deep radicular grooves scored as ASUDAS grades 3 and 4. In the middle and middle-apical planes, the presence of the combinations Ver1-AS3 and VerV-AS3 showed a high risk of presenting a critical dentine thickness of 0.6 mm. Therefore, these root canal walls with less dentine thickness represent potential instrumentation danger zones in mandibular first premolars with C-shaped canals.

Mandibular pre-molars endodontic anatomy and role in sex dimorphism for Western Asia population using CBCT 3d imaging technique / Anatomía endodóntica de premolares mandibulares y papel en el dimorfismo sexual para la población de Asia Occidental utilizando la técnica de imagen 3d CBCT

SUMMARY: Cone Beam Computerized Tomography (CBCT) imaging technique can be used for identifying the root canal anatomy and its use in determining sexual dimorphism. The aim of current study was to identify the commonly found root canal morphology and gender dimorphism for mandibular pre-molars in Western Asia population according to Vertucci's classification using CBCT 3D imaging technique. On ethical approval 470 patients from Western Asia population with intact healthy mandibular first and second pre-molars were included in the study. The selected patients were sent to radiology department of Riyadh Elm University, Saudi Arabia for CBCT images. The observations recorded included: i) number of roots; and ii) type of root canal morphology based on Vertucci's classification. All the mandibular first and second pre-molars had single root both in males and females. The type of Vertucci's classification commonly observed was Type I both in males (88.94 %) and females (100 %) in mandibular first pre-molars. Similarly Type I was identified as a common root canal configuration in mandibular second pre-molars for males (82.77 %) and females (100 %). The two canal configurations Type IV and V were only observed in the males. It can be concluded from the results mandibular first and second pre-molars in the Western Asia population are single rooted with common Vertucci's Type I canal configuration in the females with rare evidence of two canals in males. Additionally CBCT is an effective technique and should be used for detection of root canals in the mandibular pre-molars which can aid dentists in providing a successful endodontic therapy.

RESUMEN: La imagen de la tomografía computarizada de haz cónico (CBCT) se puede utilizar para identificar la anatomía del conducto radicular y para determinar el dimorfismo sexual. El objetivo del estudio fue identificar la morfología del conducto radicular y el dimorfismo de sexo, comúnmente encontrados en los premolares mandibulares en la población de Asia occidental, de acuerdo con la clasificación de Vertucci, utilizando la técnica de imágenes CBCT 3D. Tras la aprobación ética, se incluyeron en el estudio 470 pacientes de la población de Asia occidental con primeros y segundos premolares mandibulares sanos intactos. Los pacientes seleccionados fueron enviados al departamento de radiología de la Universidad de Riyadh Elm, Arabia Saudita, para las imágenes CBCT. Las observaciones incluyeron: i) número de raíces; y ii) tipo de morfología del conducto radicular según la clasificación de Vertucci. Se observó solamente una raíz en los primeros y segundos premolares mandibulares tanto en hombres como en mujeres. El tipo de clasificación de Vertucci comúnmente observado fue Tipo I tanto en hombres (88,94 %) como en mujeres (100 %) en los primeros premolares mandibulares. El Tipo I se identificó como una configuración común del conducto radicular en los segundos premolares mandibulares para hombres (82,77 %) y mujeres (100 %). Ambas configuraciones de canal Tipo IV y V solo se observaron en los varones. Se puede concluir a partir de los resultados de los primeros y segundos premolares mandibulares en la población de Asia occidental, que éstos tienen una sola raíz con una configuración de canal de Vertucci Tipo I común en mujeres con una evidencia de dos canales infrecuente en los hombres. La CBCT es una técnica eficaz y debe usarse para la detección de conduc- tos radiculares en los premolares mandibulares, lo que puede ayu- dar a los dentistas a proporcionar una terapia endodóntica exitosa.

Endodontic Management of a Two-rooted Mandibular First Premolar with Five Root Canals with Cone-beam Computed Tomography: A Case Report.

Proper knowledge of the anatomic structure of the root canal system is a vital prerequisite for successful root canal therapy. This report presents the endodontic management a two-rooted lower first premolar with five root canals. A similar case has not been reported to date. The use of cone beam computed tomography (CBCT) in rare and doubtful cases helps establish an accurate diagnosis and render successful endodontic treatment thereafter. This article helps broaden our knowledge about the possible anatomic diversities as to teeth with more roots and root canals than expected normally.

Preparation of the lingual canal in mandibular first premolar with canal bifurcation.

The aim of this study was to establish an effective method of locating and negotiating the lingual canal in mandibular first premolars with two canals during root canal preparation. A total of 125 mandibular first premolars with radicular grooves were collected, and after micro-computed tomography scanning, 50 mandibular first premolars with a Vertucci V/III canal form were selected based on the inclusion criteria. Access cavities were prepared, and the lingual canals (LCs) were searched in four following steps: step 1 direct vision and a straight K-file; step 2 stereomicroscopy and a straight K-file; step 3 stereomicroscopy and a pre-curved K-file; and step 4 a long-neck bur. After localization, the LCs were instrumented. In most cases, access to the LC was achieved by step 2 (19/50, 38%) or step 3 (22/50, 44%). In three cases (6%), step 1 alone was enough to achieve access to the orifice, and in six cases (12%), access to the lingual canal was not achieved until step 4. Overall, 43 of the 50 mandibular first premolars (86%) were successfully instrumented, and the remaining seven failed. Two cases failed in the process of negotiating the canal to full length and five cases failed due to procedural errors (ledge formation, canal perforation, vertical fracture, or instrument separation). The LC in mandibular first premolars is a major endodontic challenge. A stereomicroscope and a pre-curved K file are suggested to be valuable tools for detecting and accessing the extra LC.

Primer premolar inferior con dos conductos y doble trayecto fistuloso: caso clínico / First lower premolar with two canals and double fistulous path: a clinical case

El tratamiento endodóntico del primer premolar inferior, cuando presenta varios conductos o varias raíces puede ser un gran desafío. En el presente trabajo se describe un caso clínico de un paciente de sexo masculino de 60 años de edad que concurre al Servicio de Guardia de la Facultad de Odontología de la Universidad de Buenos Aires (FOUBA). Al examen clínico y radiográfico se descubre la presencia de dos trayectos fistulosos que corresponden a la misma pieza dentaria con diagnóstico de absceso alveolar crónico. Concluimos que el operador debe realizar un minucioso diagnóstico, y analizar y conocer las diferentes configuraciones anatómicas para tratarlas adecuadamente, aumentando así las probabilidades de éxito del tratamiento (AU)

Endodontic treatment of the first lower premolar when it has multiple ducts or multiple roots can be a challenge. This paper describes a clinical case of a 60-year-old male patient who attends the on-call service of the School of Dentistry of the University of Buenos Aires (FOUBA). Upon clinical and radiographic examination, the presence of two sinusal tracts that corresponded to the same dental piece with a diagnosis of chronic alveolar abscess was discovered. We conclude that the operator must carry out a thorough diagnosis and analyze and understand the different anatomical configurations in order to properly treat them, thus increasing the probability of treatment success (AU)

3-Dimensional Analysis and Systematic Review of Root Canal Morphology and Physiological Foramen Geometry of 109 Mandibular First Premolars by Micro-computed Tomography in a Mixed Swiss-German Population.

INTRODUCTION: The aim of this study was to systematically revise the root canal configuration (RCC) literature and to investigate the root canal morphology of mandibular first premolars (Ma1Ps) of 2 populations by means of micro-computed tomographic imaging. METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines including RCC randomized controlled trials and cross-sectional, cohort, comparative, validation, and evaluation studies. Furthermore, the RCC, physiological foramina, the frequency of accessory and connecting canals, and the physiological foramina morphology of 109 Ma1Ps were investigated by means of micro-computed tomographic imaging. The RCC results are described using a 4-digit system code. RESULTS: The most frequent RCCs observed were 1-1-1/1 (70.6%), 1-1-2/2 (7.3%), 1-2-2/2 (7.3%), and 1-2-1/1 (5.5%). Accessory canals were observed in 31.2%. Connecting canals were observed in 1-1-2/2 (4.6%), 1-2-2/2 (4.6%), 1-1-2/1 (1.8%), and 1-2-1/1 (1.8%) RCCs. Accessory foramina were observed in 52.3%; 30.3% of the Ma1Ps had 1 accessory foramen, 12.8% had 2, 2.8% had 3, 2.8% had 4, 2.8% had 5, and 0.92% had 6. The narrow and wide diameter mean of 136 physiological foramina was 0.28 mm (±0.9) and 0.37 mm (±0.11) when only 1 physiological foramen was present. CONCLUSIONS: This study provides detailed root canal morphology of Ma1Ps in a Swiss-German population. Within the limitations of the study, the authors recommend a final physiological foramen preparation size of instrument tip sizes 30-40; yet, such a decision should be carefully considered on an individual basis.

Cone-beam computed tomography study of C-shaped root canal of mandibular premolars / 口腔疾病防治

Objective@#To investigate the incidence and morphology of C-shaped root canals in mandibular premolars by cone-beam computed tomography (CBCT) imaging, which provides a reference for clinical diagnosis and treatment.@*Methods @#The CBCT scanning data of 964 mandibular first premolars and 907 mandibular second premolars in 508 cases were collected, and the root canal morphology, incidence of C-shaped root canals, bilateral symmetry and location of radicular grooves were analyzed.@*Results@#The incidence of C-shaped root canals in mandibular first premolars was 4.1% and that in mandibular second premolars was 0.6%. The incidence of C-shaped root canals of mandibular first premolars was significantly higher than that of mandibular second premolars (χ2=25.775, P < 0.001). The symmetrical ratio of C-shaped root canals in the mandibular first premolars was 29%. There were no symmetrical C-shaped root canals in the mandibular second premolars. There were significant differences in the distribution of the C-shaped root canal configuration in the root canal (P < 0.001). The C-shaped configuration mainly existed in the middle axial and apical level of the mandibular premolars. The C2 type was more common. No C-shape was found in the coronal level of the mandibular premolars. Vertucci I single tube type was the most common type of root canal for the mandibular premolars included in this study; the incidences were 81.7% and 98.3% for the mandibular first and second premolars, respectively, and the difference was statistically significant (χ2=140.544, P < 0.001). The other root canal types of mandibular first premolars were more than those of mandibular second premolars. The incidences of Vertucci Ⅱ, Ⅲ, Ⅳ, and Ⅴ and C-shaped root canals in mandibular first premolars were significantly higher than those in mandibular second premolars. C-shaped root canal mandibular premolars had radicular grooves, and most of them were located at the mesiolingual side.@*Conclusion@# The morphology of the C-shaped root canal in mandibular premolars was complicated. CBCT can provide direct and accurate imaging evidence for clinical diagnosis and treatment.

Methodological Approach to the Endodontic Treatment of First Premolars with Three Root Canals: Two Case Reports.

AIM: The aim of this article was to promote a methodology in the endodontic management of complex premolars with multiple root canals Background: The success of endodontic treatment depends on a meticulous clinical and radiographic analysis, the creation of a suitable access cavity and chemical and mechanical preparation, followed by three-dimensional filling of the entire root canal system. Consequently, it is essential to look for the presence of additional root canals to prevent endodontic treatment failure Case description: Two cases are presented. The first case concerned a 50-year-old male patient of North African origin who consulted in the context of a global prosthetic restoration including endodontic treatment of the maxillary left first premolar (tooth no. 24). The second case concerned a 29-year-old male patient of North African origin who was referred to us by his primary care practitioner in an urgent context of pain and infection present for two weeks (tooth no. 44). In both cases, it was the in-depth radiographic analysis, combined with manual exploration under the surgical micro- scope, that led to the relatively rare identification of a third root canal. Shaping, disinfection and three-dimensional filling of the entire root canal system were then performed in accordance with widely validated protocols. CONCLUSION: The maxillary and mandibular premolars, due to their highly variable root canal system configuration and a number of root canals and roots, appear to be teeth for which treatment is potentially complex. The acuteness of digital-tactile sense and the advent of 3D imaging and optical aids optimize the treatment of all the root canals of a tooth Clinical significance: These case reports demonstrate the importance of clinical and radiographic inspections to guide practitioners in the search for additional root canals in premolars and promote a methodological approach.

Radicular Groove Accessory Canal Morphology in Mandibular First Premolars: Micro-computed Tomographic Study.

INTRODUCTION: The purpose of this study was to investigate the morphologic features of radicular groove accessory canals (RGACs) in mandibular first premolars and their relationship to root anatomy by micro-computed tomographic imaging. METHODS: A total of 154 single-rooted mandibular first premolars with radicular grooves were selected. The teeth were scanned by micro-computed tomographic imaging, and the following parameters were recorded: (1) the presence of RGACs, (2) the origin of RGACs, (3) the position of the RGAC foramen in the groove in relation to root length, (4) the foramen diameter, (5) the type of groove present according to the Arizona State University dental anthropology scoring system (ASUDAS), and (6) the type of anatomy present according to Vertucci's classification. The data were recorded and statistically analyzed using the chi-square test (P < .05). RESULTS: The incidence of RGACs in the teeth was 49.9%. The average distance from the cementoenamel junction plane to the RGAC foramen was 8.83 ± 2.53 mm, and the majority of the RGAC foramina were located in the middle third. Regarding the severity of the groove, the presence of RGACs was significantly higher for groups ASUDAS 3 and 4 compared with ASUDAS 1 and 2 (85.7% and 14.3%, respectively). The presence of at least 1 RGAC was greatest for Vertucci type V (46%) and for more complex types (46%) when compared with Vertucci types I and III. CONCLUSIONS: Mandibular first premolars with radicular grooves often present with RGACs. An association between the internal and external anatomy and the presence of RGACs was detected in this study.

Occlusal Stress Distribution on the Mandibular First Premolar - FEM Analysis.

OBJECTIVE: The aim of this paper was to analyze the distribution of stress and deformation on the mandibular first premolar under two types of loading (axial and para-axial load of 200 N) using the FEM computer method. MATERIALS AND METHOD: For this research a µCT scan of the first mandibular premolar was used, and the method used in this research was FEM analysis under two types of loading. RESULTS: The values of the von Mises stress measured in the cervical part of an intact tooth under axial load were up to 12 MPa, and under paraaxial load over 50 MPa. The values of the stress measured on the bottom of the noncarious lesion are very high ≈ 240 Mpa. Stress values in the cervical part of the intact tooth are higher in the zone of the sub-surface enamel. The deformation values of the tooth under para-axial loading were ≈ 10 times higher than the value of the deformation under axial load. The greatest deformations were seen in the area of the tooth crown. CONCLUSIONS: Occlusal loading leads to significant stress in the cervical part of teeth. The values of the measured stress are greater under the action of paraxial load. The values of stress in abfraction lesions measured under a paraxial load are extremely high. Exposing the lesion to further stress will lead to its deepening. The total deformation of the entire tooth under paraxial load was ≈ 10 times higher compared to the deformation value of the tooth under axial load.

Mandibular first premolar apical morphology: A stereomicroscopic study.

The aim of this study was to investigate the size, shape and position of the physiological foramen and the relationship between the age and gender to the location and size of the apical foramen of mandibular first premolars. One hundred and one extracted human mandibular first premolar teeth were examined; age and gender of the patients were recorded. Apices of teeth were examined stereomicroscopically for number, size and shape of apical foramina; frequency and deviation of accessory foramina from the apex and the relation with age and gender. Sixty-four of the premolars had one foramen and 23% had two. The distances from the foramina openings to the apices ranged from 0.07 to 2.18 mm. In younger range irregular shape was dominant (41%), whilst in older range, round shape was dominant (45%). The shape of the apical foramen changed with age and the distance from the foramen to the anatomical apex increased with age.

Root canal morphology of the mandibular first premolars in a Yucatecan population using cone beam computed tomography: an in vitro study / Morfología del conducto radicular de primeros premolares mandibulares en una población yucateca usando tomografía computarizada: estudio in vitro

A successful endodontic treatment requires knowledge of the internal configuration of dental root canals. Most of the people who live in Yucatan are of Maya origin, characterized by a Mongoloid dental pattern. Because of their ethnicity, variations are expected. The purpose of this investigation is to assess the morphological characteristics and variability of this population. One hundred and five extracted first mandibular premolars of Mexican Maya population were analyzed; the sample was obtained from the Oral Surgery Clinic in the School of Dentistry at the Autonomous University of Yucatan with written informed consent. Analyses were performed by means of Cone Beam Computed Tomography. Vertucci´s Type I was the most prevalent configuration with 51.4 %, but 41 cases (39.1 %) presented a radicular groove and a C-shaped canal configuration. Overall, we documented 1, 2, 3, and 4 root canals. Mandibular first premolars are very variable in the Yucatecan population. The variability and frequency of C-shape is similar to mandibular second molars confirming the importance of the ethnic background for the endodontic treatments.

El éxito en el tratamiento endodóntico requiere el conocimiento profundo de la configuración interna del sistema de conductos radiculares. La mayoría de las personas que viven en Yucatán son de origen Maya y poseen el patron dental Mongoloide; por lo tanto, se esperan variaciones debido a su etnicidad. El propósito de esta investigación fue evaluar las características morfológicas y la variabilidad del conducto radicular en la población yucateca. Se analizaron ciento cinco primeros premolars mandibulares extraídos de pacientes provenientes de una muestra Maya mexicana; la muestra fue obtenida de la Clínica de Cirugía Oral de la Facultad de Odontología de la Universidad Autónoma de Yucatán. Con consentimiendo informado escrito. Se utilizaron Tomografías Computarizadas para el análisis de la muestra. La configuración más prevalente fue la Tipo I de Vertucci con 51,4 %. Sin embargo, 41 de 105 casos (39,1 %) presentaron un surco radicular y la configuración en forma de "C". Se documentaron casos con 1, 2, 3 y 4 conductos radiculares. Los primeros premolares mandibulares de la población Yucateca son muy variables. La variabilidad y frecuencia de conductos en forma de "C" concuerda con estudios realizados en segundos molars mandibulares en esta zona confirmando la importancia del origen étnico de las poblaciones para los tratamientos endodónticos.

Diagnosis and endodontic treatment in a mandibular first premolar with two canals: case report / Diagnóstico e tratamento endodôntico em primeiro pré-molar inferior com dois condutos radiculares: relato de caso

Objective: The objective of this article was to describe the diagnosis and the endodontic treatment of a mandibular first premolar with two root canals. Case report: A 67-year-old female patient presented to the dental clinic referring pain in the right mandibular first premolar. The patient reported induced pain and the sensation of "grown tooth". Clinical examination revealed a marked degree of dental abrasion associated with a slight swelling in the periapical region and positive percussion and cold tests. The radiographic examination revealed an apical radiolucency. A pulpal diagnosis of necrotic pulp and chronic perirradicular periodontitis were made. After access cavity, the canals were prepared using K-files, Gates-Glidden drills and 2.5% sodium hypochlorite. Gutta-percha cones and AH-Plus sealer were used during obturation with the lateral condensation technique. Conclusion: After a period of 23 months of follow-up, clinical and radiographic examinations revealed total regression of the lesion.

Objetivo: O objetivo deste artigo foi descrever o diagnóstico e tratamento endodôntico de um primeiro pré-molar inferior com dois canais radiculares. Relato de caso: Paciente de 67 anos de idade apresentou-se à clínica odontológica referindo dor no primeiro pré-molar inferior. A paciente relatava dor espontânea e sensação de "dente crescido". O exame clínico revelou um grau acentuado de abrasão dentária associada a ligeiro inchaço na região periapical e respostas positivas aos testes de percussão e frio. O exame radiográfico revelou a presença de uma radiolucência apical. Foi realizado o diagnóstico de polpa necrótica e periodontite perirradicular crônica. Após a realização da cavidade de acesso, os canais foram preparados utilizando limas tipo K, brocas Gates-Glidden e hipoclorito de sódio a 2,5%. Cones de guta-percha e cimento obturador AH-Plus foram utilizados na obturação com a técnica de condensação lateral. Conclusão: Após um período de 23 meses de acompanhamento, os exames clínicos e radiográficos revelaram regressão total da lesão.

Cone-beam Computed Tomographic Evaluation and Endodontic Management of a Mandibular First Premolar with Type IX Canal Configuration: Case Report.

INTRODUCTION: Mandibular premolars exhibit considerable variations in their root canal system that can be particularly difficult to diagnose. Avoiding mishaps and successful nonsurgical endodontic therapy depends on an absolute understanding of the root and root canal morphology to locate, prepare, and obturate the canals. METHODS: This case report describes the endodontic therapy of a mandibular first premolar with 2 roots and 3 canals with confirmation of cone-beam computed tomography. It also cites the incidence of morphologic variations reported in mandibular first premolars, based on ethnic diversity. RESULT: Cone-beam computed tomography (axial and sagittal sections) confirmed the presence of 2 roots and 3 canals in a mandibular first premolar. Here, the main canal divided into 3 root canals at the middle third, otherwise described as Sert and Bayirli's type IX canal configuration. CONCLUSION: The occurrence of documented cases of a mandibular first premolar with Sert and Bayirli's type IX root canal configuration is rare. Failure to recognize a second and third canal in the present case might have otherwise resulted in endodontic reinfection.

Complicated Root Canal Configuration of Mandibular First Premolars Is Correlated with the Presence of the Distolingual Root in Mandibular First Molars: A Cone-beam Computed Tomographic Study in Taiwanese Individuals.

INTRODUCTION: The purpose of this study was to examine the frequency and bilateral consistency of distolingual roots (DLRs) in permanent mandibular first molars (PMFMs) and root canal configurations in PMFPs (permanent mandibular first premolars) and to determine the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. METHODS: A total of 932 cone-beam computed tomographic images of PMFMs and PMFPs were collected from 233 patients. The frequency and bilateral consistency of DLRs in PMFMs along with root canal configurations (root number and canal number) of PMFPs were recorded and evaluated ipsilaterally and contralaterally. Multivariable logistic regression analysis was used to evaluate the correlation between the root canal configurations of PMFPs with the appearance of DLRs in PMFMs. RESULTS: The prevalence of PMFMs with DLRs was 24.7%, and the incidence of complicated root canal configurations of PMFPs was 26.6%. The incidence of complicated root canal configurations of PMFPs was 19.6% in the non-DLR group, 37.2% in the unilateral DLR group, and 44.7% in the bilateral DLR group. After adjusting for categoric variables including sex, age, and side, the odds ratios for the frequency of complicated root canal configurations of PMFPs in the unilateral DLR and bilateral DLR groups compared with the non-DLR group were 2.472 (95% confidence interval, 1.434-4.263; P = .001) and 3.392 (95% confidence interval, 1.976-5.823; P < .001), respectively. CONCLUSIONS: An increasing and corresponding trend between the presence of DLRs in PMFMs and complicated root canal configurations in PMFPs was noted in Taiwanese individuals. These results suggest that the clinicians should familiarize themselves with the anatomic variants of PMFMs and PMFPs before endodontic treatment.

The root canal morphology in mandibular first premolars: a comparative evaluation of cone-beam computed tomography and micro-computed tomography.

OBJECTIVES: This study evaluated the accuracy of cone-beam computed tomography (CBCT) in detecting the root canal morphology of mandibular first premolars using micro-computed tomography (micro-CT) as a reference standard. MATERIALS AND METHODS: In total, 143 extracted human mandibular first premolars were selected and scanned using micro-CT and CBCT. The acquired images were used to evaluate the root canal morphology in each tooth, and evaluations were repeated after 2 weeks. The root canal configurations observed on the three-dimensional images were recorded, and the findings from both modalities were compared using chi-square tests. The actual agreement between the two modalities was assessed using kappa statistics. RESULTS: In total, the root morphologies in 136 mandibular first premolars were consistently identified by both CBCT and micro-CT: type I in 104, type III in five, type V in 20, and type IX in seven. Of the remaining seven teeth, the morphology in two, one, and four teeth was identified as type I, type VII, and type IX (type 1-3 in two and type 1-2-3 in two), respectively, by micro-CT and misdiagnosed as type III, type V, and type V, respectively, by CBCT. There were no significant differences between the two modalities with regard to the accurate detection of root canal configurations, with a kappa value of 0.886 for the actual agreement. CONCLUSIONS: Although CBCT may be accurate in detecting the root canal configuration in mandibular first premolars, it produces poorer image details compared with micro-CT. CLINICAL RELEVANCE: CBCT is a reliable radiological technique, but its accuracy in detecting details of the root canal morphology in mandibular first premolars, especially in some complex root canal configurations, needs to be improved.