Exploración del conducto en C con tomografía computada de haz cónico / Exploration of C-shaped canals with cone-beam computed tomography

El «conducto en C¼ es un tipo de anatomía dentaria compleja que debe ser evaluado previo a la realiza- ción de un tratamiento endodóntico. Esta variación anatómica es vista principalmente en segundos mola- res inferiores aunque también puede encontrarse en premolares y molares, tanto superior como inferior. Para su diagnóstico se solicitan distintos tipos de estudios imagenológicos. Debemos tener en cuenta que este tipo de anatomía no es observado fácilmen- te en imágenes bidimensionales por lo cual es muy importante considerar para estos casos complejos, la solicitud de un estudio de alta complejidad como lo es la tomografía computada de haz cónico, la cual nos permitirá explorar este tipo de anatomía para tenerlo en cuenta al momento de realizar un correcto aborda- je del conducto en C (AU)

The "C-canal" is a type of complex dental anatomy that must be evaluated prior to performing endodontic treatment. This anatomical variation is seen mainly in lower second molars although it can also be found in premolars and molars, both upper and lower. For its diagnosis we can use different types of imaging studies. We must keep in mind that this type of anatomy is not easily observed in two-dimensional images, which is why it is very important to consider, for these complex cases, the request for a highly complex study such as cone beam computed tomography, which will allow us to explore this type of anatomy to take it into account when performing a correct approach to the C-duct (AU)

Root Canal Treatment of Mandibular First Premolar with 3 Canals: A Case Report / Tratamiento Endodóntico de Primer Premolar Mandibular con 3 Canales: Reporte de un Caso

SUMMARY: The mandibular first premolar is commonly a single-rooted tooth with occasional presentation of radicular variations. This tooth usually has one root with only one canal (97.9 %). Presence of three canals is very rare. Anomalies may appear during odontogenesis which can lead to anatomical variations in teeth. Similarly, these variations may be associated with characteristics that can be attributed to specific population groups. Due to their low frequency, these additional canals can easily be missed. For this reason, a meticulous knowledge of tooth morphology and their possible anatomical variations are necessary, and the presence of extra roots and canals should be always considered before initiation of root canal treatment. Additionally, different radiographs and appropriated access cavity preparation is needed to ensure a success endodontic treatment. This article reports a diagnosis and endodontic treatment of a mandibular first premolar with three canals.

El primer premolar mandibular suele ser un diente unirradicular con presentación ocasional de variaciones radiculares. Este diente suele tener una raíz con un solo conducto (97,9 %). La presencia de tres canales es muy rara. Durante la odontogénesis pueden aparecer anomalías que pueden provocar variaciones anatómicas en los dientes. De manera similar, estas variaciones pueden estar asociadas con características que pueden atribuirse a grupos de población específicos. Debido a su baja frecuencia, estos canales adicionales pueden pasar desapercibidos fácilmente. Por esta razón, es necesario un conocimiento meticuloso de la morfología dental y sus posibles variaciones anatómicas, y siempre se debe considerar la presencia de raíces y conductos adicionales antes de iniciar el tratamiento de conducto. Además, se necesitan diferentes radiografías y una preparación adecuada de la cavidad de acceso para garantizar un tratamiento de endodoncia exitoso. Este artículo reporta un diagnóstico y tratamiento endodóntico de un primer premolar mandibular con tres canales.

Identificação de Enterococcus SPP e Enterobacteriaceae em canais radiculares com infecção primária e secundária ou persistente / Identification of Enterococcus spp and Enterobacteriaceae in root canals with primary and secondary or persistent infection

O objetivo do presente estudo foi identificar microrganismos das espécies Enterococcus spp e Enterobacteriaceae em dentes com canais radiculares infectados portadores de infecção primária e/ou secundária/persistente. Métodos: A amostra do presente estudo foi de 23 pacientes que apresentaram necessidade de tratamento ou retratamento endodôntico. Foram coletadas amostras de 28 dentes infectados usando pontas de papel absorventes estéreis, transportadas em solução salina, diluídas, plaqueadas e incubadas em estufa de cultura bacteriológica. Para o crescimento de microrganismos foram utilizados jarros com gerador de atmosfera de anaerobiose. Colônias microbianas foram isoladas, caracterizadas e identificadas. Os dados coletados foram estatisticamente analisados com a utilização do software SPSS for Windows 10.0 (SPSS Inc., USA). Resultados: Foi isolada somente uma cepa do gênero Enterococcus spp, e nenhuma espécie do gênero Enterobacteriaceae. Das coletas microbiológicas realizadas em 28 canais radiculares, todas apresentaram crescimento microbiano em anaerobiose. Dezoito dentes apresentavam necrose pulpar e lesão periapical. Os outros 10 dentes já haviam recebido tratamento endodôntico prévio e em 6 destes houve constatação de lesão periapical, sendo que nos outros 4, não. Conclusão: Nas condições experimentais do presente estudo, pode-se concluir que não houve correlação da presença de espécies microbianas das famílias Enterococcus spp e/ou Enterobacteriaceae com infecção primária ou secundária do canal radicular.

The objective of the present study was to identify microorganisms of the Enterococcus spp and Enterobacteriaceae species in teeth with infected root canals with primary and/or secondary/persistent infection. Methods: The sample of the present study consisted of 23 patients who required endodontic treatment or retreatment. Samples of 28 infected teeth were collected using sterile absorbent paper points, transported in saline solution, diluted, plated and incubated in a bacteriological culture oven. For the growth of microorganisms, jars with an anaerobic atmosphere generator were used. Microbial colonies were isolated, characterized and identified. The collected data were statistically analyzed using the SPSS for Windows 10.0 software (SPSS Inc., USA). Results: Only one strain of the genus Enterococcus spp was isolated, and no species of the genus Enterobacteriaceae. From the microbiological collections carried out in 28 root canals, all showed microbial growth in anaerobic conditions. Eighteen teeth had pulp necrosis and periapical lesion. The other 10 teeth had already received previous endodontic treatment and in 6 of them there was a periapical lesion, and in the other 4, no. Conclusion: Under the experimental conditions of the present study, it can be concluded that there was no correlation between the presence of microbial species of the Enterococcus spp and/or Enterobacteriaceae families with primary or secondary root canal infection.

Evaluation of the root morphology of mandibular first premolars using cone-beam computed tomography in a peruvian population / Evaluación de la morfología radicular de primeros premolares mandibulares mediante tomografía computarizada de haz cónico en una población peruana

Introduction: The morphology of the root canal of the first premolars is not always the same and therefore a good knowledge of its dental anatomy is essential. Aim: To assess the morphology of roots and root canals of mandibular first premolars in a Peruvian population using cone-beam computed tomography (CBCT). Materials and Methods: This was a descriptive cross-sec-tional study. A total of 370 mandibular first premolars fulfilling the inclusion criteria were evaluated using CBCT, and the number of roots and root canals, the Vertucci's classification of root canal configuration, age, sex and side of the tooth were registered. Results: One and two roots were presented in 96.2% (n=356) and 3.8% (n=14), respectively, of the mandibular first premolars analyzed, and one canal was present in 67.6% (n=250) and two canals in 32.2% (n=119). A type I root canal configuration was found in 67.6% (n=250) of the cases followed by type V with 26.2% (n=97). A statistically significant association was found between the number of roots and canals (p<0.001) and age also had a significant influence on this variable (p=0.0043). Conclusions: The presence of one canal in mandibular first premolars is the most frequent, although there is a considerable prevalence of two in the population studied. The number of roots is associated with the number of canals, with age having a significant influence on these variables.

Introducción: La morfología del canal radicular de los primeros premolares no siempre es la misma y por ello es fundamental un buen conocimiento de su anatomía dental. Objetivo: Evaluar la morfología de las raíces y conductos radiculares de primeros premolares mandibulares en una población peruana mediante tomografía computarizada de haz cónico. Materiales y Métodos: Este fue un estudio transversal descriptivo. Se evaluaron mediante tomografías un total de 370 primeros premolares mandibulares que cumplían con los criterios de inclusión, y se registró el número de raíces y conductos radiculares, la clasificación de Vertucci de la configuración radicular, la edad, el sexo y el lado del diente. Se realizaron las pruebas de chi-cuadrado y una regresión logística binaria (p<0,05). Resultado: Se presentó una y dos raíces en el 96,2% (n=356) y 3,8% (n=14), respectivamente, de los primeros premolares mandibulares analizados, y un canal estuvo presente en el 67,6% (n=250) y dos canales en el 32,2% (n=119). Se encontró una configuración del conducto radicular tipo I en el 67,6% (n=250) de los casos seguido del tipo V con un 26,2% (n=97). Se encontró una asociación estadísticamente significativa entre el número de raíces y conductos (p<0.001) y la edad también influyó significativamente en esta variable (p=0.0043). Conclusión: La presencia de 1 canal en primeros premolares mandibulares es la más frecuente, aunque existe una prevalencia considerable de 2 en la población estudiada. El número de raíces está asociado al número de canales, teniendo la edad una influencia significativa en estas variables.

Morphology of the Second Mesiobuccal Canal in the Maxillary Second Molar / Morfología del Segundo Canal Mesiovestibular en el Segundo Molar Maxilar

SUMMARY: Failure to locate a complete canal system affects the prognosis of root canal treatment. A missed root canal is one of the most common reasons for failed root canal treatment. The prevalence of the second mesiobuccal canal in the maxillary second molar is relatively high and has a variety of configurations. Therefore, knowledge of its morphology is required in clinical endodontics. This review presented the canal in terms of its prevalence, classification, anatomical features, and the method for locating the second mesiobuccal canal in the maxillary second molar. Root canal treatment requires knowledge of tooth morphology, appropriate access preparation, and a thorough examination of the tooth's interior. Thus, clinicians should carefully employ various methods for assessing the anatomy of the entire root canal system to prevent failure in locating the second mesiobuccal canal. This canal can be located by modifying the access cavity design and utilizing specific instruments to improve the second mesiobuccal canal system visualization.

La falta de localización de un sistema completo de canal afecta el pronóstico del tratamiento de éste. La omisión de un tratamiento de canal es uno de los motivos más frecuentes por las que el tratamiento de canal fracasa. La prevalencia del segundo canal mesiovestibular en el segundo molar superior es relativamente alta y tiene una variedad de configuraciones. Por tanto, el conocimiento de su morfología es necesario en endodoncia clínica. Esta revisión presentó el canal en términos de su prevalencia, clasificación, características anatómicas y el método para localizar el segundo canal mesiovestibular en el segundo molar superior. El tratamiento de canal requiere conocimiento de la morfología del diente, una preparación adecuada del acceso y un examen exhaustivo del interior del diente. Por lo tanto, los dentistas deben emplear cuidadosamente varios métodos para evaluar la anatomía de todo el sistema de canales radiculares para evitar fallas en la localización del segundo canal mesiovestibular. Este canal se puede localizar modificando el diseño de la cavidad de acceso y utilizando instrumentos específicos para mejorar la visualización del sistema del segundo canal mesiovestibular.

Comparación de la actividad antimicrobiana de cementos selladores en endodoncia / Comparison of the antimicrobial activity of sealing cements in endodontics

Introducción: la persistencia de microorganismos en los conductos radiculares es uno de los principales factores del fracaso endodóncico. Por ello la importancia de conocer las propiedades antimicrobianas de los distintos tipos de selladores. Objetivo: realizar una comparación con base en la evidencia disponible sobre la actividad antimicrobiana de los diferentes cementos selladores en endodoncia. Material y métodos: la información fue recopilada de las bases de datos PubMed y Google Académico en el idioma inglés y español, publicados en el periodo 2014-2023. Resultados: un gran número de microorganismos se encuentran presentes en los diferentes tipos de infecciones de origen endodóncico, se han identificado más de 500 especies microbianas, entre ellas bacterias, hongos, arqueas y virus. Los cementos selladores se pueden clasificar según su composición química, en cementos a base de óxido de zinc-eugenol, hidróxido de calcio, a base de ionómero de vidrio, silicona, resina y biocerámicos. Conclusión: los cementos selladores que mostraron mayor actividad antimicrobiana contra los microorganismos persistentes fueron los cementos a base de óxido de zinc-eugenol, resina y biocerámicos. Sin embargo, se identificó que cada autor utilizó diferentes métodos y tiempos, por lo tanto, no es posible lograr definir con exactitud qué cemento sellador posee la mejor capacidad antimicrobiana (AU)

Introduction: the persistence of microorganisms in root canals is one of the main factors of endodontic failure. Therefore, the importance of knowing the antimicrobial properties of the different types of sealants. Objective: to make a comparison based on the available evidence on the antimicrobial activity of the different endodontics sealers. Material and methods: the information was collected from PubMed and Google Academic databases in English and Spanish, published in the period 2014-2023. Results: a large number of microorganisms are present in the different types of infections of endodontic origin, more than 500 microbiological species have been identified, including bacteria, fungi, archaea and viruses. Sealer cements can be classified according to their chemical composition, into cements based on zinc oxide-eugenol, calcium hydroxide, based on glass ionomer, silicone, resin and bioceramics. Conclusion: sealer cements that showed the highest antimicrobial activity against persistent microorganisms were zinc oxide-eugenol, resin, and bioceramic-based cements. However, it was identified that each author used different methods and times, therefore, it is not possible to accurately define which sealer cement has the best antimicrobial capacity (AU)

Microcomputed-Tomographic Analysis of the Root Canal Morphology of the Mandibular First Molars in a Malaysian Subpopulation Using Two Classification Systems / Análisis por Tomografía Microcomputada de la Morfología del Conducto Radicular de los Primeros Molares Mandibulares en una Subpoblación de Malasia Utilizando dos Sistemas de Clasificación

SUMMARY: This work investigated the morphology of the root canal system of the mandibular first molar in a Malaysian subpopulation. Using micro-computed tomography with an isotropic resolution of 22 µm, 140 mandibular first molars were scanned. MIMICS software was used for segmentation, 3-D reconstruction and analysis of the acquired images. The canal configuration was described using Vertucci [supported by the supplementary configurations proposed by Sert & Bayirli (2004)] and Ahmed et al. (2027), coding systems. The chi-square test was used to assess the association between qualitative variables. By non-considering intercanal communications, Vertucci types IV (17.1%) and I (76.4%) were the most frequently reported configurations in the mesial and distal roots, respectively. Of the reported configurations, 24.3% and 4.3% were non-classifiable by Vertucci system in the mesial and distal roots, respectively. Up to 63.6% and 9.3% of the reported configurations were non- classifiable, and type I was the most frequent when considering intercanal communications (7.1% and 76.4% in the mesial and distal roots, respectively). According to Ahmed et al., system, almost half of the sample had more than four digits (47.9%), followed by the 3-digits category (20.71%). In both systems, a significant association was found between the canal configuration and the root type (p<0.001). The mandibular first molar of this Malaysian subpopulation demonstrated a wide range of root canal morphology. When compared to the Vertucci system, the system developed by Ahmed et al., successfully classified all molars configurations despite their level of complexity. The complex canal anatomy of mandibular first molars in this subpopulation warrants special attention during root canal treatment procedures.

En este trabajo se investigó la morfología del sistema de conductos radiculares del primer molar mandibular en una subpoblación de Malasia. Utilizando tomografía microcomputada con una resolución isotrópica de 22 µm, se escanearon 140 primeros molares mandibulares. Se utilizó el software MIMICS para segmentar (enmascarar), reconstruir en 3D, visualizar y analizar las imágenes adquiridas. La configuración del canal se describió utilizando Vertucci respaldado por las configuraciones complementarias propuestas por Sert & Bayirli (2004)] y Ahmed et al. (2017, 2020), sistemas de codificación. Se utilizó la prueba de chi-cuadrado para evaluar la asociación entre variables cualitativas. Sin considerar las comunicaciones intercanales, los tipos Vertucci IV (17,1%) y I (76,4%) fueron las configuraciones reportadas con mayor frecuencia en las raíces mesiales y distales, respectivamente. De las configuraciones reportadas, el 24,3 % y el 4,3 % fueron no clasificables por el sistema de Vertucci en las raíces mesial y distal, respectivamente. Hasta el 63,6 % y el 9,3 % de las configuraciones reportadas fueron no clasificables, siendo la tipo I la más frecuente al considerar las comunicaciones intercanales (7,1 % y 76,4 % en las raíces mesiales y distales, respectivamente). Según Ahmed et al. (2017, 2020) en el sistema, casi la mitad de la muestra tenía más de cuatro dígitos (47,9 %), seguido por la categoría de 3 dígitos (20,71 %). En ambos sistemas se encontró una asociación significativa entre la configuración del canal y el tipo de raíz (p<0,001). El primer molar mandibular de esta subpoblación de Malasia demostró una amplia gama morfológica del conducto radicular. En comparación con el sistema Vertucci, el sistema desarrollado por Ahmed et al. (2017, 2020) clasificaron con éxito todas las configuraciones de los molares a pesar de su nivel de complejidad. La compleja anatomía del canal de los primeros molares mandibulares en esta subpoblación merece una atención especial durante los procedimientos de tratamiento de conducto.

Accuracy of Working Length Determination - Electronic Apex Locator Versus Cone Beam Computed Tomography

ABSTRACT Objective: To compare the accuracy of working length determination between cone beam computed tomography (CBCT) and electronic apex locator by measuring the actual working length of teeth. Material and Methods: A total of 150 single-rooted tooth assessed by radiograph undergoing root canal therapy were selected. The process was repeated to obtain a buccolingual and mesiodistal section of all teeth. The measurement line was considered from the reference occlusal plane following the center of the canal to the terminus. All information regarding the accuracy of cone-beam computed tomography and apex locator was noted in a pre-designed proforma. Results: CBCT consistently demonstrated high accuracy across all tooth types in both jaws. The electronic apex locator exhibited varying precision, with greater accuracy observed in the mandible. Statistical analyses revealed significant differences in electronic apex locator accuracy among tooth types in the maxilla (p=0.042), emphasizing the importance of specific clinical considerations. Conclusion: Cone beam computed tomography emerges as a reliable diagnostic tool for accurate working length determination, especially in complex cases, while the electronic apex locator remains valuable with careful consideration of potential variations in accuracy. An individualized approach, considering tooth type, jaw location, and clinical context, is crucial for precise working length determination in endodontic practice.

Prevalencia de conductos en C de segundos molares mandibulares evaluados en tomografía de haz cónico / Prevalence of C-ducts of Mandibular Second Molars Evaluated on Cone Beam Tomography

Introducción: El conocimiento adecuado de la configuración de conductos radiculares es fundamental en endodoncia; la evaluación tomográfica permite una correcta evaluación de su disposición radicular. Objetivo: Determinar la prevalencia de conductos en C de segundos molares mandibulares, evaluados en tomografía de haz cónico. Métodos: Se realizó un estudio descriptivo y de corte transversal; la muestra estuvo conformada por 200 segundos molares mandibulares permanentes de una población peruana, observadas en tomografías cone beam, donde se registró la presencia del conducto en C, su configuración según la clasificación de Fan y el sexo del paciente. Resultados: La prevalencia de la configuración radicular en forma de C en segundos molares inferiores fue del 65,5 por ciento; según la Clasificación de Fan se observó mayor prevalencia en el tercio cervical del conducto radicular el tipo C1 con 85,7 por ciento; en el tercio medio el tipo C2 con 42,9 por ciento; a nivel apical fue el tipo C3C con 72,1 por ciento; según el sexo, el 65,2 por ciento de los conductos en C correspondió al femenino. Conclusión: La prevalencia de los conductos en C de los segundos molares mandibulares evaluados en tomografías de haz cónico fue de 65,5 por ciento con mayor predominio en el sexo femenino. La evaluación tomográfica permite una mejor identificación y configuración interna de los conductos radiculares(AU)

Introduction: Adequate knowledge of the configuration of root canals is fundamental in endodontics; tomographic evaluation allows a correct assessment of their radicular arrangement. Objective: To determine the prevalence of C-shaped canals in mandibular second molars, evaluated by cone beam tomography. Methods: A descriptive and cross-sectional study was carried out; the sample consisted of 200 permanent mandibular second molars from a Peruvian population, observed in cone beam tomography, where the presence of the C-shaped canal, its configuration according to Fan's classification and the patient's gender were recorded. Results: The prevalence of the C-shaped root canal configuration in lower second molars was 65.5 percent; according to the Fan classification, the highest prevalence was observed in the cervical third of the root canal, type C1 with 85.7 percent; in the middle third, type C2 with 42.9 percent; at the apical level it was type C3C with 72.1 percent; according to gender, 65.2 percent of the C-shaped canals corresponded to females. Conclusion: The prevalence of C-shaped canals in mandibular second molars evaluated in cone beam tomography was 65.5% with a higher predominance in the female gender. The tomographic evaluation allows a better identification and internal configuration of the root canals(AU)

Evaluation of different methods of calcium hydroxide removal from root canals with simulated internal resorptions / Avaliação de diferentes métodos de remoção de hidróxido de cálcio de canais radiculares com reabsorções internas simuladas

Objective: This study evaluated different methods of calcium hydroxide (CH) removal from root canals with simulated internal resorptions using microcomputed tomography (micro-CT). Material and Methods: Sixty acrylic resin blocks with simulated root canals and internal resorptions were prepared using a Reciproc R25 file and then filled with CH. The blocks were divided into five test groups (n=12) according to the method used for CH removal: hand files (HF), Easy Clean (EC), passive ultrasonic irrigation (PUI), XP-Endo Finisher (XP), XP-Endo Finisher + PUI (XP+PUI). The blocks were scanned using a SkyScan 1172 scanner before and after CH removal to measure the volume and percentage of CH removal. The OriginPro 2017 software was used for statistical analyses. The level of significance was set at p<0.05 for all tests. Results: No method under study removed all CH. All methods had similar results in the cervical third (P>0.05). The percentage of CH removal was significantly greater in the area of internal resorption and along the total length of the canal in the XP+PUI group (P<0.05). The best results of CH removal were found in the apical third of roots in the XP+PUI and PUI groups (P>0.05). Conclusion: No method removed all CH from the root canals, but the combined XP+PUI method removed more CH than the other methods, especially from the area of the internal resorption(AU)

Objetivo: Este estudo avaliou diferentes métodos de remoção de hidróxido de cálcio (CH) de canais radiculares com reabsorções internas simuladas por meio de microtomografia computadorizada (micro-CT). Material e Métodos: Sessenta blocos de resina acrílica com canais radiculares simulados e reabsorções internas foram preparados com lima Reciproc R25 e posteriormente preenchidos com CH. Os blocos foram divididos em cinco grupos de teste (n=12) de acordo com o método utilizado para remoção de CH: limas manuais (HF), Easy Clean (EC), irrigação ultrassônica passiva (PUI), XP-Endo Finisher (XP), XP -Endo Finalizador + PUI (XP + PUI). Os blocos foram escaneados usando um scanner SkyScan 1172 antes e depois da remoção do CH para medir o volume e a porcentagem de remoção do CH. O software OriginPro 2017 foi utilizado para análises estatísticas. O nível de significância foi estabelecido em p<0,05 para todos os testes. Resultados: Nenhum método em estudo removeu todos o CH. Todos os métodos tiveram resultados semelhantes no terço cervical (P>0,05). A porcentagem de remoção de CH foi significativamente maior na área de reabsorção interna e ao longo do comprimento total do canal no grupo XP+PUI (P<0,05). Os melhores resultados de remoção de CH foram encontrados no terço apical das raízes nos grupos XP+PUI e PUI (P>0,05). Conclusão: Nenhum método removeu todo o CH dos canais radiculares, mas o método combinado XP+PUI removeu significativamente mais CH do que os outros métodos, especialmente da área de reabsorção interna (AU)

Frecuencia y tipología del segundo conducto mesiovestibular en primeros molares superiores / Frequency and typology of the second mesiobuccal canal in maxillary first molars

Objetivos: Evaluar mediante microscopia quirúrgica la presencia del segundo conducto mesiovestibular (MV2) en el piso de la cámara pulpar de los primeros molares superiores, determinar su abordabilidad, establecer el calibre de lima que llegó al tercio apical y tipificar radiovisiográficamente su morfología se-gún la clasificación de Weine. Materiales y métodos: Se utilizaron 48 primeros molares superiores huma-nos extraídos. Sé tomaron radiovisografías preope-ratorias (Carestream 5200) en sentido orto radial y mesio-distal. Se realizó apertura y se localizó entra-da del MV2 con microscopio quirúrgico (Newton MEC XXI, Argentina) a 16 x. Se cateterizó MV1 y MV2 con limas tipo K #10 y #15 (Dentsply Maillefer). Se cortó raíz distovestibular para mejorar visualización ra-diovisográfica. Se tomó conductometria en sentido mesio-distal para establecer la tipología. Se compa-raron frecuencias y porcentajes mediante test de Chi-cuadrado con corrección de Yates, prueba exac-ta de Fisher y test z para diferencia de proporcio-nes. Se calcularon intervalos de confianza 95% para porcentajes mediante método score de Wilson. Re-sultados: El 54% (26 casos) presentó MV2. De los 26 MV2, el 77% (20 casos) fueron abordables, porcen-taje significativamente mayor al 23% no abordable (z=3,62; P<0,05). Al hacer cateterismo, hubo asocia-ción significativa entre tipo de conducto (MV1 y MV2) y calibre de lima que llegó al tercio apical (Chi-cua-drado=29,12; gl=1; P<0,05). La tipología I (58%) fue significativamente mayor que las tipologías II (21%) y III (21%) (P<0,05 para ambas comparaciones). Con-clusión: El alto porcentaje de piezas que presentó MV2 evidencia la importancia clínica de detectarlo y tratarlo correctamente. Dado el alto porcentaje de piezas donde fue abordable, se concluye que el clíni-co debe tener conocimiento, destreza y la tecnología necesaria para poder abordarlo. Si bien la tipología I (58%) fue la más encontrada, cuando el MV2 termina en foramen independiente (tipo III), su omisión puede conducir al fracaso del tratamiento (AU))

Objectives: To evaluate by surgical microscopy the presence of second mesiobuccal canal (MB2) in the pulp chamber floor of the maxillary first molars, determine its approachability, establish the caliber of the file that reached the apical third, and radiographically typify its morphology according to Weine ́s classification. Materials and methods: 48 extracted human maxillary first molars were used. Preoperative radiovisographies (Carestream 5200) were taken in ortho-radial and mesio-distal direction. Coronal access was made and the entrance of MB2 was located with a surgical microscope (Newton MEC XXI, Argentina) at 16x. MB1 and MB2 were catheterized with K files #10 and #15 (Dentsply Maillefer). Distobuccal root was cut to improve radiovisographic visualization. Conductometry was taken in mesio-distal direction to establish the typology. Frequencies and percentages were compared using Chi-square test with Yates correction, Fisher's exact test and z test for difference in proportions. 95% confidence intervals were calculated for percentages using Wilson score method. Results: 54% (26 cases) presented MB2. Of the 26 MB2, 77% (20 cases) were approachable, a significantly higher percentage than those not approachable (z=3.62; P<0.05). When performing catheterization, there was a significant association between type of canal (MB1 and MB2) and file caliber that reached the apical third (Chi-square=29.12; df=1; P<0.05). Typology I (58%) was significantly higher than typologies II (21%) and III (21%) (P<0.05 for both comparisons). Conclusion: The high percentage of specimens that showed MB2 evidence the clinical importance of detecting and treating it correctly. Given the percentage of pieces where it was approachable (77%), it is concluded that the clinician must have the knowledge, skill and necessary technology to be able to approach it. Although typology I (58%) was the most found, when MB2 ends an independent foramen (type III), its omission can lead to treatment failure (AU)

Extrusão apical de irrigantes em dentes imaturos utilizando diferentes dispositivos de irrigação por pressão negativa / Apical extrusion of irrigants in immature teeth using different negative pressure irrigation devices

Objetivo: O objetivo deste estudo foi avaliar a extrusão apical de irrigantes em dentes imaturos simulados, comparando a irrigação convencional com outros dispositivos de irrigação por pressão negativa. Materiais e Métodos: 48 amostras de dentes imaturos simulados foram montadas em um modelo adaptado para conter o irrigante extravasado e distribuídas igualmente em 4 grupos (n=12) de acordo com o dispositivo de irrigação utilizado: Grupo Irrigação Convencional (IC), Grupo EndoVac (EV), Grupo Pulp Sucker (PS) e Grupo Ivac (IV). As amostras foram irrigadas com 15mL de solução irrigadora, sendo 10mL de NaOCl a 2,5% e 5mL de EDTA a 17% intercalados. As amostras foram pesadas em balança de precisão antes e depois dos procedimentos de irrigação, sendo a diferença entre os pesos final e inicial considerado o volume de irrigante extravasado. Os dados foram coletados e analisados estatisticamente pelos testes de Kruskal-wallis e exato de Fisher. Resultados: Os grupos que utilizaram pressão negativa promoveram significativamente menor volume de irrigante extravasado que o grupo IC (p<0,05), não havendo diferenças significativas quando comparados entre si (p>0,05). Houve diferenças significativas na associação entre os grupos e a extrusão de irrigante, sendo o grupo PS menos associado a extrusão de irrigante (p<0,005). Discussão: Estudos anteriores apontam os dispositivos de pressão negativa como opções seguras diante de extravasamento de irrigantes quando comparados à irrigação convencional. Conclusão: A irrigação convencional promoveu significativamente maior volume de extrusão de irrigante quando comparada aos dispositivos de irrigação por pressão negativa. O sistema PulpSucker mostrou extravasamento de irrigante em um número significativamente menor de amostras.

Aim: The aim of this study was to evaluate the apical extrusion of irrigants in simulated immature teeh, comparing convencional irrigation with other negative pressure irrigation devices. Materials and methods: 48 samples of simulated immature teeth were set up in an adapted model to contain the extravasated irrigant and evenly distributed into 4 groups (n=12) according to the device used: Convencional Irrigation Group (CI), EndoVac Group (EV), Pulp Sucker Group (PS) and Ivac Group (IV). The samples were irrigated with 15mL of irrigant solution, consisting of 10mL NaOCl 2,5% and 5mL EDTA 17%, in na alternating sequence. The samples' weights were measured using a precision scale before and after the irrigation procedures, with the difference between de final and initial weights considered the volume of extravasated irrigant. Data were collected and statistically analyzed by Kruskal-wallis and Fisher exact tests. Results: The groups that used negative pressure devices significantly promoted a lower volume of extruded irrigant than the CI group (p<0,05), with no significant differences between the negative pressure groups (p>0,05). There were signficant differences in the association between the groups and irrigant extrusion, with the PS group showing significantly less association with irrigant extrusion (p<0,005). Discussion: Previous studies have indicated that negative pressure devices are safe alternatives to convencional irrigation when considering irrigant extrusion. Conclusion: Conventional irrigation promoted a significantly greater volume of irrigant extrusion when compared to negative pressure irrigation devices. The PulpSucker system showed irrigant extravasation in significantly fewer samples.

Estado actual de la infección focal y del éxito del tratamiento endodóntico / Current status of focal infection and the success of endodontic treatment

Frente a la difusión en medios de comunicación de medias verdades con enunciados alarmantes y anticientíficos, este editorial busca revisar las bases científicas para determinar el comportamiento clínico. Así, el texto discurre por el concepto de infección focal desde su origen, yendo al encuentro de sus transformaciones conceptuales a través de los descubrimien- tos científicos, teniendo en cuenta las características emocio- nales propias de cada paciente como un todo y los peligros a los que se puede estar expuestos frente a las medias verdades (AU)

Facing the diffusion of alarming and anti-scientific state- ments in the media, this editorial seeks the scientific bases to determine the clinical behavior. Thus, the text runs through the concept of focal infection from its origin and across its conceptual transformations through scientific discoveries, by considering the emotional characteristics of each patient as a whole and the dangers to which they may be exposed in the face of half-truths (AU)

Influencia de la Morfología Externa de la Raíz de Primeros Premolares Superiores en la Sobreestimación del Espesor Radiográfico Radicular Durante la Preparación para Poste, Evaluados Mediante Tomografía Computarizada Cone Beam / Influence of the External Morphology of the Root of Upper First Premolars on the Overestimation of Radiographic Root Thickness During Post Preparation, Evaluated by Cone Beam Computed Tomography

La investigación tuvo como objetivo determinar la influencia de la morfología externa de la raíz de primeros premolares superiores en la existencia de sobreestimación radiográfica durante la preparación para poste. Con este fin se realizó un estudio transversal in vitro, donde 60 premolares superiores uniradiculares fueron instrumentadas con fresas Gates Glidden y Pesso de calibre 1, 2 y 3. Seguidamente se obtuvieron imágenes radiográficas digitales de cada pieza dentaria mediante un aparato posicionador a una distancia constante en sentido vestíbulo lingual, asimismo se realizaron imágenes tomográficas volumétricas de las muestras. En ambas técnicas imagenológicas se midió el espesor a mesial y distal de las piezas. La sobreestimación fue calculada mediante la diferencia de la medida tomográfica menos la radiográfica. Los resultados indicaron que en ambas paredes radiculares hubo diferencia significativa entre las medidas radiográficas y tomográficas (p<0,05), encontrándose en la pared distal diferencias altamente significativas (p<0,001); además se evidenció que la sobreestimación radiográfica fue mayor en la pared distal. El estudio concluyó que existe sobreestimación radiográfica en premolares superiores durante la preparación para poste de un 20,42 % en promedio, siendo la pared distal la estructura que presenta mayor sobreestimación.

SUMMARY: he investigation´s objective was to determine the influence of external morphology of the root of upper first premolars in the existence of radiographic overestimation during preparation for post. An in vitro cross-sectional study was carried out, where 60 single-rooted upper premolars were instrumented with burs. Gates Glidden and Pesso of caliber 1, 2 and 3, then, digital radiographic images of each dental piece were obtained by means of a positioning device at a constant distance in the buccolingual direction; volumetric tomographic images of the samples were also performed. In both imaging techniques, the mesial and distal thickness of the pieces was measured. The overestimation was calculated by the difference of the tomographic measurement minus the radiographic one. The results indicated that in both root walls there was a significant difference between the radiographic and tomographic measurements (p<0.05), with highly significant differences being found in the distal wall (p<0.001); In addition, it was evidenced that the radiographic overestimation was greater in the distal wall. The study concluded that there is radiographic overestimation in upper premolars during post preparation of 20.42% on average, with the distal wall being the structure that presents the greatest overestimation.

Segundo Conducto Mesiovestibular en Molares Superiores: Prevalencia y Análisis Anatómico Mediante Tomografía Computarizada de Haz Cónico / Second Mesiobuccal Canal in Maxillary Molars: Prevalence and Anatomical Analysis Through Cone Beam Computed Tomography

El objetivo de este estudio fue utilizar la Tomografía Computarizada de Haz Cónico (TCHC) para investigar la configuración anatómica, prevalencia y distribución del conducto mesiovestibular Dos (MV2) en molares superiores de una subpoblación chilena, considerando variables como la presencia del conducto MV2, la clasificación de Vertucci, el género y edad. Estudio observacional de corte transversal. La muestra consistió en Tomografías Computarizadas de Haz Cónico tomadas en la clínica odontológica de la Universidad Andrés Bello (Viña del Mar). Se calculó el tamaño muestral utilizando la fórmula de población conocida, lo que resultó en 262 tomografías. Los examinadores se calibraron utilizando el coeficiente Kappa de Cohen, para luego analizar las variables mediante un estudio imagenológico utilizando el software I-CAT Visión. Se analizaron 439 primeros y segundos molares superiores. La prevalencia del conducto MV2 en primeros molares fue del 63,74 %, mientras que, en segundos molares, fue del 20,04 %. La prevalencia en primeros molares fue mayor en hombres (73,86 %) que en mujeres (58,62 %), mientras que, en segundos molares, fue del 15,81 % en mujeres y del 28,41 % en hombres. En relación con la edad, en los primeros molares la diferencia fue significativa en el rango de 18 a 40 años (66,49 %). En cuanto al tipo de configuración según Vertucci (2005), el 70 % de los primeros molares presentó una configuración Tipo II, y un 23,65 % Tipo IV, con resultados similares en los segundos molares. El presente estudio demostró que los conductos MV2 son frecuentes en la población analizada, especialmente en los primeros molares, y que la configuración Tipo II es la más prevalente. Además, se observó una mayor prevalencia en hombres y en el rango de 18 a 40 años. Estos hallazgos proporcionan información relevante sobre la anatomía radicular en la población y pueden contribuir a mejorar los resultados de tratamiento.

SUMMARY: The aim of this study was to use Cone-beam Computed Tomography (TCHC) to investigate the anatomical configuration, prevalence, and distribution of the Second Mesiobuccal (MB2) canal in upper molars of a Chilean subpopulation, considering variables such as the presence of MB2 canal, Vertucci classification, gender, and age. Cross-sectional observational study. The sample consisted of TCHC scans taken at the dental clinic of Universidad Andrés Bello (Viña del Mar). The sample size was calculated using the formula for known population, resulting in 262 scans. The examiners were calibrated using Cohen's Kappa coefficient, then the variables were analyzed through an imaging study using I-CAT Vision software. 439 first and second upper molars were analyzed. The prevalence of MB2 canal in first molars was 63.74 %, while in second molars, it was 20.04 %. The prevalence in first molars was higher in males (73.86 %) than in females (58.62 %), while in second molars, it was 15.81 % in females and 28.41 % in males. Regarding age, in first molars the difference was significant between the age range of 18 to 40 years (66.49 %). Regarding the type of configuration according to Vertucci, 70 % of the first molars had Type II configuration, and 23.65 % had Type IV, with similar results in second molars. The present study demonstrated that MB2 canals are frequent in the analyzed population, especially in first molars, and Type II configuration is the most prevalent. Additionally, a higher prevalence was observed in males and in the age range of 18 to 40 years. These findings provide relevant information about root anatomy in the studied population and can contribute to improving treatment outcomes.

Bypass de instrumento endodôntico fraturado: relato de caso / Bypass of a fractured endodontic instrument: case report

Introdução: Mesmo com toda evolução tecnológica desses instrumentos, com o desenvolvimento das limas de liga de níquel-titanio (NiTi) e sistemas mecanizados, as fraturas podem ocorrer durante o preparo químico/mecânico. Existem três abordagens mais regulamente aplicadas para solucionar essa intercorrencia: tentativa de remoção do instrumento com ultrassom, tentativa de ultrapassálo (bypass) ou a obturação do segmento. Objetivo: Relatar um caso da técnica de bypass em instrumento fraturado no canal radicular. Descrição do caso: Paciente, sexo feminino, 47 anos, brasileira, sem condições sistêmicas associadas, foi encaminhada à clínica do Curso de Odontologia da UNIFENAS, Divinópolis, Minas Gerais, Brasil, para resolução de fratura de instrumento no canal mésio- vestibular do primeiro molar superior direito (16). Optou-se pelo tratamento pela técnica de bypass, que envolveu as seguintes etapas: anestesia, abertura, utilização de lima C-Pilot #08 para ultrapassar o instrumento fraturado, odontometria, escalonamento regressivo a partir da lima k#20, desinfecção com hipoclorito de sódio 5%, medicação com hidróxido de cálcio por 21 dias, agitação da substância irrigadora e obturação dos canais radiculares. Conclusão: O bypass ao instrumento é uma técnica conservadora, eficaz e uma solução adequada em casos de fratura de limas endodônticas dentro dos canais radiculares. Essa técnica visa preservar o máximo possível da estrutura dental original, evitando procedimentos mais invasivos.(AU)

Introduction: Even with all technological evolution of these instruments, with the development of nickel-titanium alloy (NiTi) files and mechanized systems, fractures can occur during chemical/mechanical preparation. There are three most commonly applie to resolve this complication: attempting to remove the instrument with ultrasound, attempting to bypass it, or obturating the segment. Objective: To report a case of bypass technique in fractured instrument in the root canal. Case description: A 47-year-old female patient from Brazil, with no associated systemic conditions, was referred to the clinic of the Dentistry Course at UNIFENAS, Divinópolis, Minas Gerais, Brazil, for resolution of an instrument fracture in the mesio-vestibular canal of the right upper first molar (16). Treatment was performed using the bypass technique, which involved the following steps: anesthesia, opening, use of a C-Pilot #08 file to bypass the fractured instrument, odontometry, regressive scaling from the k#20 file, disinfection with 5% sodium hypochlorite, medication with calcium hydroxide for 21 days, agitation of the irrigating substance and root canal filling. Conclusion: Instrument bypass is a conservative, effective technique and an adequate solution in cases of endodontic file fracture within root canals. This technique aims to preserve as much of the original tooth structure as possible, avoiding more invasive procedures.(AU)

Tratamento de lesão periradicular, de origem endodôntica, com auxílio de laserterapia: uma revisão sistemática da literatura e apresentação se caso clínico / Treatment of periradicular injury, of endodontic origin, with the aid of laser therapy: a systematic review of the literature and presentation if clinical case

É sabido que a cavidade oral é a porta de entrada para muitos microrganismos e que possui alguns gêneros de bactérias que quando se associam ou proliferam em excesso, com a falta de higienização correta, fatores ambientais e imunológicos podem causar danos em algumas partes dos dentes como no tecido pulpar e canais radiculares. Neste sentido, a endodontia tem sido capaz de tratar pessoas com problemas dentários em fases muito precoces como as medidas profiláticas até casos infeciosos que afetam a polpa dos dentes causando as lesões perirradiculares que são infecções causadas por microrganismos, Para tanto, é necessário que a odontologia ofereça transformações positivas por meio de técnicas que sejam mais previsíveis para os tratamentos. A literatura tem indicado o uso da laserterapia como técnica auxiliar para o tratamento endodôntico pelo seu potencial mínimo invasivo, preciso e eficaz em menor tempo de cura de patologias orais como as lesões perirradiculares. Este estudo pretendeu abordar a importância da laserterapia sobre as variáveis patológicas de pacientes com lesão perirradiculares. Para realiza-lo foi necessário buscar na literatura estudos que associem este tipo de tratamento e sua eficiência no tratamento desta patologia. Para realizar esta pesquisa foi necessário buscar dados na literatura que tratam sobre o tema para investigar o tempo indicado ao tratamento com a laserterapia bem como o estágio em que as lesões podem ser tratadas com auxílio deste método. Corroborando com o estudo apresentamos um caso clínico(AU)

It is known that the oral cavity is the gateway to many microorganisms and that it has some genera of bacteria that when they associate or proliferate in excess, with the lack of correct hygiene, environmental and immunological factors can cause damage in some parts of the teeth such as in pulp tissue and root canals. In this sense, endodontics has been able to treat people with dental problems at very early stages such as prophylactic measures to infectious cases that affect the pulp of teeth causing perirradicular lesions that are infections caused by microorganisms, therefore, it is necessary that dentistry offer positive transformations through techniques that are more predictable for treatments. The literature has indicated the use of laser therapy as an auxiliary technique for endodontic treatment for its minimal invasive, precise and effective potential in shorter time of cure of oral pathologies such as perirradicular lesions. This study aimed to address the importance of laser therapy on the pathological variables of patients with perirradicular lesions. To accomplish this, it was necessary to seek studies in the literature that associate this type of treatment and its efficiency in the treatment of this pathology. To carry out this research it was necessary to seek data in the literature that deal with the subject to investigate the time indicated for treatment with laser therapy as well as the stage at which lesions can be treated with the aid of this method. Corroborating the study, we present a clinical case(AU)

Maxillary Molar Root Canal Morphology Using Cone-Beam Computed Tomography: An Epidemiological Study from Shandong Province, China / Morfología del Conducto Radicular del Molar Maxilar Mediante Tomografía Computarizada de Haz Cónico: Un Estudio Epidemiológico de la Provincia de Shandong, China

SUMMARY: The objective of this study was to evaluate the maxillary molar root canal morphology in individuals from the Shandong province, China, using cone-beam computed tomography (CBCT) and classify it based on Ahmed et al. (2017) classification system to obtain a reference for clinical diagnosis and treatment. From December 2020 to June 2021, we screened CBCT data of 1,619 patients at the Jinan Stomatological Hospital who had been indicated for CBCT because of various oral abnormalities. The root and root canal morphologies of all teeth were statistically analyzed, and the root canal morphology was classified based on Ahmed et al. (2017) classification system. In the maxillary molars, three roots were the most common, accounting for 99.24 % and 74.61 % of all maxillary first and second molars, respectively. Two roots were the second most common, accounting for 0.66 % and 17.29 % of all maxillary first and second molars, respectively. Root morphology variation, e.g., fusion or furcation defect, was present in 22 (0.76 %) maxillary first molars and 765 (25.39 %) maxillary second molars, with the most common being mesiobuccal and distobuccal root fusion. Detection rates of a second mesiobuccal canal (MB2) in the maxillary first and second molars were 48.5 % and 26.5 %, respectively. Among age groups, the frequency of MB2 was the highest in the 15-24-year-old group and lowest in the 55-64-year-old group. Bilateral MB2 root canals were present in 64.8 % and 48.4 % of the maxillary first and second molars, respectively. Men and women accounted for 60.6 % and 67.8 % of the maxillary first molars, respectively, and 51.7 % and 45.6 % of the maxillary second molars, respectively. According to Ahmed et al. (2017) classification of root canal morphology, 18 and 22 root canal configurations were found in 1,453 right maxillary first molars and 1,444 left maxillary first molars, respectively. The right maxillary first molars showed three two-rooted, 14 three-rooted, and one four-rooted type. The left maxillary first molars showed two one-rooted, six two-rooted, and 14 three-rooted types. According to Ahmed et al. (2017) classification of root canal morphology, 43 and 45 root canal configurations were found in 1,507 right maxillary second molars and 1,506 left maxillary second molars, respectively. The right maxillary second molars showed 17 one-rooted, 16 two- rooted, eight three-rooted, and two four-rooted types. The left maxillary second molars showed 19 one-rooted, 13 two-rooted, 12 three- rooted, and one four-rooted type. This study showed that the maxillary molar root canal morphology is diverse in the Shandong province. Ahmed et al. (2017) classification system provides a clear description of the root canal morphology. CBCT can be used to study complex root and root canal morphologies.

El objetivo de este estudio fue evaluar la morfología del conducto radicular del molar superior en individuos de la provincia de Shandong, China, utilizando tomografía computarizada de haz cónico (CBCT) y clasificarla con base en el sistema de clasificación de Ahmed et al. (2017) para obtener una referencia para diagnóstico clínico y tratamiento. Desde diciembre de 2020 hasta junio de 2021, analizamos los datos de CBCT de 1619 pacientes en el Hospital Estomatológico de Jinan a quienes se les indicó CBCT debido a diversas anomalías orales. Las morfologías de la raíz y del conducto radicular de todos los dientes se analizaron estadísticamente, y la morfología del conducto radicular se clasificó según el sistema de clasificación de Ahmed et al. (2017). En los molares superiores, tres raíces fueron las más comunes, representando el 99,24 % y el 74,61 % de todos los primeros y segundos molares superiores, respectivamente. Dos raíces fueron las segundas más comunes, representando el 0,66 % y el 17,29 % de todos los primeros y segundos molares superiores, respectivamente. La variación de la morfología de la raíz, por ejemplo, fusión o defecto de furcación, estuvo presente en 22 (0,76 %) primeros molares superiores y 765 (25,39 %) segundos molares superiores, siendo la fusión radicular mesiovestibular y distovestibular la más común. Las tasas de detección de un segundo canal mesiovestibular (MB2) en los primeros y segundos molares superiores fueron del 48,5 % y 26,5 %, respectivamente. Entre los grupos de edad, la frecuencia de MB2 fue más alta en el grupo de 15 a 24 años y más baja en el grupo de 55 a 64 años. Los conductos radiculares MB2 bilaterales estaban presentes en el 64,8 % y el 48,4 % de los primeros y segundos molares superiores, respectivamente. En los hombres y en las mujeres representaron el 60,6 % y el 67,8 % de los primeros molares superiores, respectivamente, y el 51,7 % y el 45,6 % de los segundos molares superiores, respec- tivamente. Según la clasificación de la morfología del conducto radicular de Ahmed et al. (2017) se encontraron configuraciones de conducto radicular 18 y 22 en 1453 primeros molares superiores derechos y 1444 primeros molares superiores izquierdos, respectivamente. Los primeros molares superiores derechos mostraron tres tipos de dos raíces, 14 de tres raíces y uno de cuatro raíces. Los primeros molares superiores izquierdos mostraron dos tipos de una raíz, seis de dos raíces y 14 de tres raíces. Según la clasificación de la morfología del conducto radicular de Ahmed et al. (2017) se encontraron configuraciones de conducto radicular 43 y 45 en 1507 segundos molares superiores derechos y 1506 segundos molares superiores izquierdos, respectivamente. Los segundos molares superiores derechos mostraron 17 tipos de una raíz, 16 de dos raíces, ocho de tres raíces y dos de cuatro raíces. Los segundos molares superiores izquierdos mostraron 19 de una raíz, 13 de dos raíces, 12 de tres raíces y uno de cuatro raíces. Este estudio mostró que la morfología del conducto radicular del molar superior es diversa en la provincia de Shandong. El sistema de clasificación de Ahmed y colaboradores proporciona una descripción clara de la morfología del conducto radicular. CBCT se puede utilizar para estudiar morfologías complejas de raíces y conductos radiculares.

Prevalencia del segundo conducto en dientes anteroinferiores usando Tomografía Computadorizada Cone Beam / Second root canal prevalence in lower anterior teeth using Cone Beam Computed Tomography

Introducción: Es un error común pensar que los dientes anteroinferiores, por lo general, tienen un solo conducto radicular con una sola raíz. Sin embargo, un estudio realizado por Vertucci et. al., (1974), mostraron una alta prevalencia (13%) de dos conductos radiculares en los dientes anteroinferiores, lo que estimuló más investigaciones. Objetivo: El propósito de este estudio fue determinar la prevalencia del segundo conducto radicular en los dientes anteroinferiores en una población nicaragüense, estos fueron detectados por medio de tomografía computadorizada (Cone Beam). Materiales y Métodos: En el estudio se analizaron 293 piezas dentales, de canino a canino de la arcada inferior. Para realizar el análisis se utilizó el software libre Radiant DICOM Viewer 2021.2.2, se realizaron cortes sagitales, axiales y coronales para ver la prevalencia del segundo conducto radicular. Resultados: De las 293 piezas dentarias analizadas se encontró que 259 presentaban un solo conducto que correspondía al 88.4% y 34 dientes presentaban dos conductos que correspondían al 11.6%. De acuerdo con el análisis tomográfico, se encontró que en los cortes axiales y sagitales fue donde se observó la presencia del segundo conducto. Con respecto a la presencia del segundo conducto de acuerdo al tercio del canal radicular se identificó que la mayoría se presentó en el tercio medio (52.94%), seguido por coronal (29.41%) y por último el tercio apical (17.65%). De acuerdo con la clasificación de Vertucci se encontró que se presenta un mayor porcentaje del tipo I con 88.40%, seguido por el tipo III con 4.44%, después el tipo V con 3.41%, y el tipo II con 2.39%. El de menor porcentaje fue el tipo VI con 1.37%, mientras que, en las piezas analizadas, no se encontraron los tipos IV, VII y VIII. Conclusión: Basados en los resultados obtenidos en este estudio, la prevalencia de un segundo conducto en dientes anteroinferiores fue de 11.6%.

Title The prevalence of a second root canal in mandibular anterior teeth using Cone Beam Computed Tomography. Abstract Introduction: It is a common misconception that the mandibular anterior teeth usually have a single root canal with a single root. However, a study by Vertucci et. al., (1974), showed a high prevalence (13%) of two root canals in the lower anterior teeth, which stimulated further investigations. Objective: The purpose of this study was to determine the prevalence of the second root canal in the mandibular anterior teeth in a Nicaraguan population, these were detected by means of computed tomography (Cone Beam). Materials and methods: In the study, 293 teeth were analyzed, from canine to canine of the mandibular teeth. To perform the analysis, the free software Radiant DICOM Viewer 2021.2.2 was used, sagittal, axial and coronal views were made to see the prevalence of the second root canal. Results: Of the 293 teeth analyzed, it was found that 259 had a single root canal corresponding to 88.4%, and 34 teeth had two root canals corresponding to 11.6%. According to the tomographic analysis, it was found that the presence of the second root canal was observed only in the axial and sagittal views. Regarding the presence of the second canal according to the third of the root canal, it was identified that the majority presented in the middle third (52.94%), followed by coronal (29.41%) and finally the apical third (17.65%). According to the Vertucci classification, it was found that there is a higher percentage of type I with 88.40%, followed by type III with 4.44%, then type V with 3.41%, and type II with 2.39%. The one with the lowest percentage was type VI with 1.37%, while in the pieces analyzed, types IV, VII and VIII were not found. Conclusion: Based on the results obtained in this study, the prevalence of a second root canal in lower anterior teeth was 11.6%.

Descripción de la morfología del sistema de canales radiculares del primer molar maxilar mediante tomografía computarizada cone-beam en una población chilena / Description of the morphology of the root canal system of the maxillary first molar using cone-beam computed tomography in a Chilean population

Describir la morfología del sistema de canales radiculares del primer molar maxilar en una población chilena mediante exámenes de tomografía computarizada Cone-Beam (CBCT). Se realizó un estudio observacional descriptivo en el cual se utilizaron los exámenes CBCT de pacientes que fueron atendidos en un Centro de Radiología Maxilofacial privado durante el período comprendido entre Enero y Diciembre del año 2018 en la ciudad de Temuco, Chile, los cuales fueron observados de manera independiente por dos investigadores previamente calibrados. Se observaron 199 exámenes CBCT. En la raíz mesiobucal,predominaron las morfologías tipo II, I y IV de Vertucci respectivamente, mientras que en la raíz distobucal y palatina predominó la morfología tipo I. El canal MB2 estuvo presente en el 62,3 % de los casos, con una prevalencia significativamente mayor en pacientes jóvenes. En la mayoría de los primeros molares maxilares de los habitantes de la ciudad de Temuco se observaron tres raíces separadas y la presencia de cuatro canales. Se determinó una alta frecuencia del canal MB2 en la raíz MB.

SUMMARY: The objective of this study was to describe the morphology of the root canal system of the maxillary first molar in a Chilean population through Cone-Beam computed tomography (CBCT) examinations. A descriptive observational study was carried out in which the CBCT examinations of patients who were treated in a private maxillofacial radiology center during the period between January and December 2018 in Temuco, Chile, were used which were observed independently by two previously calibrated researchers. In this analysis 199 CBCT exams were observed. In the mesiobuccal root, Type II, I and IV morphologies predominated respectively, while in the distobuccal and palatal root, Type I morphology predominated. The MB2 canal was present in 62.3 % of cases, with a higher prevalence in young patients. Three separate roots and the presence of four canals were observed in most of the maxillary first molars of the patients in Temuco. A high frequency of the MB2 canal was determined in the root MB.