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.

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)

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.

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)

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.

Irrigation protocols effects on radicular dentin: Cleaning, disinfection and remaining ultrastructure / Efecto del protocolo de irrigación en la dentina radicular: limpieza, desinfección y ultraestructura remanente

A successful endodontic treatment requires a combination of satisfactory mechanical instrumentation, adequate irrigation protocols, and three-dimensional obturation of the canal system. Irrigation is considered the most critical procedure to ensure cleaning and disinfection. To date, a large variety of irrigants has been proposed. However, sodium hypochlorite (NaOCl) remains the gold standard. In order to achieve complete cleaning and disinfection, final irrigation with EDTA and ultrasonic devices has been used as an ideal protocol. Most endodontic research focuses on the cleaning and antibacterial properties of the irrigant solutions. Recent evidence demonstrated that the irrigation protocols cause erosion, affecting the radicular dentin ultrastructure. This article aims to describe the clinical features of the present knowledge concerning the effect of irrigation protocols on radicular dentin.

Un tratamiento de endodoncia exitoso requiere de una satisfactoria instrumentación mecánica, protocolos de irrigación adecuados y obturación tridimensional del sistema de conductos radiculares. La irrigación se considera el procedimiento más crítico para garantizar la limpieza y desinfección. Hasta la fecha, se ha propuesto una gran variedad de irrigantes. Sin embargo, el hipoclorito de sodio (NaOCl) sigue siendo el estándar de oro. Para lograr una limpieza y desinfección completa, se ha utilizado como protocolo ideal la irrigación final con EDTA y dispositivos ultrasónicos. La mayor parte de la investigación en endodoncia se enfoca en las propiedades antibacterianas y de limpieza de las soluciones de irrigación. Reciente evidencia demostró que los protocolos de irrigación provocan erosión, afectando la ultraestructura de la dentina radicular. Este artículo tiene como objetivo describir algunas consideraciones clínicas del conocimiento actual sobre el efecto de los protocolos de irrigación en la dentina radicular.

A new approach to endodontic access in anterior teeth: a pilot study / Uma nova abordagem para acesso endodôntico em dentes anteriores: estudo piloto

Introduction: The coronal opening is essential, during endodontic treatment, for direct access to the root canals. Usually, in the anterior teeth, endodontic access is achieved on the palatal/lingual surface, more specifically in the cingulum region. However, the lack of observation for dental positioning can lead to some accidents and complications, such as buccal perforations, causing esthetic damage and compromising the treatment. Objective: To evaluate the applicability of a new approach for performing coronal opening in anterior teeth, regarding the wear caused on the tooth crown, and to evaluate the ease of performing the new technique to minimize the risk of perforation. Material and method: Ten students (n=10) from the Improvement in Endodontics program participated in the present study. Twenty artificial teeth were used, which were upper, central incisors. Each participant performed two coronal openings. First, with no guidance (Group A - Conventional Technique) and afterward, a new opening, but with guidance with the spherical diamond tip placed parallel to the long axis of the tooth (Group B - Modified Technique). Result: The results showed that 90% of the participants considered the Modified Technique as having lower risk of accidents, as well as being easier for locating the pulp chamber. There was a statistical difference both in the measurement of the total area of wear and in the width, while there was no statistical difference in the height. Conclusion: Preliminary data collected with the survey were satisfactory for the Modified Technique. Statistically, it showed a favorable difference in relation to the area of wear and the width. However, in height there was no statistical difference.

Introdução: A abertura coronária é fundamental durante o tratamento endodôntico para um acesso direto aos canais radiculares. Em geral, em dentes anteriores, o acesso endodôntico é realizado na face palatina/lingual, mais especificamente em região de cíngulo. Entretanto, a falta de observação do posicionamento dentário pode levar a alguns acidentes e complicações, como as perfurações por vestibular, ocasionando dano estético e comprometendo o tratamento. Objetivo: Avaliar a aplicabilidade de uma nova abordagem de realização da abertura coronária em dentes anteriores, quanto ao desgaste ocasionado na coroa dentária, e avaliar a facilidade de execução da nova técnica para minimizar os riscos de perfurações. Material e método: Dez alunos (n=10) do curso de Aperfeiçoamento em Endodontia participaram do estudo. Foram utilizados vinte dentes artificiais, sendo eles incisivos centrais superiores. Cada participante realizou duas aberturas coronárias. Primeiramente sem nenhuma orientação (Grupo A - Técnica Convencional) e após, uma nova abertura, porém com orientação, com a ponta diamantada esférica posicionada paralelamente ao longo eixo do dente (Grupo B - Técnica Modificada). Resultado: Os resultados demonstraram que 90% dos participantes consideraram a Técnica Modificada como a de menor risco de acidentes e, ainda, de mais fácil localização da câmara pulpar. Houve diferença estatística tanto para a medida da área total de desgaste quanto para a largura, enquanto na altura não houve diferença estatística. Conclusão: Os dados preliminares coletados pelo questionário se mostraram satisfatórios para a Técnica Modificada. Estatisticamente, apresentou diferença favorável em relação à área de desgaste e largura, já em altura não houve diferença estatística.

Challenges faced by undergraduate dental students during root canal treatment: a survey study / Desafios enfrentados por estudantes de graduação em odontologia durante o tratamento de canal radicular: um estudo de pesquisa

Introduction: root canal treatment is a challenging procedure often first encountered by undergraduate dental students, leading to various difficulties and mistakes. Objective: this study aimed to identify the specific difficulties encountered by undergraduate dental students during root canal treatment and the frequency of mistakes they committed in relation to these difficulties. Material and method: this study employed a cross-sectional survey design. A cohort of 60 third-year students completed a self-administered questionnaire consisting of 27 questions addressing various aspects of endodontic treatment and 11 key areas of root canal procedures. The response options for each question were based on a 4-point Likert scale. Data analysis was performed using Python programming language and heatmaps were created using the seaborn library to better understand the distribution of the data. Result: students encounter challenges in developing tactile sensation, accessory cone placement, and accurately reaching the apex during canal location. Dental schools should focus on improving students' tactile skills and methods to reach the apex to enhance the effectiveness of root canal treatment education. In contrast, students reported fewer mistakes in rubber dam application and safety measures during treatment. Dental educators should emphasize proper instrument use and safety precautions during root canal treatment. Interestingly, students did not perceive these areas as problematic despite committing mistakes. Conclusion: this study provides valuable insights into the challenges and mistakes encountered by undergraduate dental students during root canal treatment. Dental educators should address these issues to improve students' skills and techniques and provide optimal patient care.

Introdução: o tratamento endodôntico é um procedimento desafiador, frequentemente encontrado pela primeira vez por estudantes de odontologia, levando a diversas dificuldades e erros. Objetivo: este estudo teve como objetivo identificar as dificuldades específicas encontradas por estudantes de graduação em Odontologia durante o tratamento endodôntico e a frequência de erros cometidos por eles em relação a essas dificuldades. Material e método: este estudo empregou um desenho de pesquisa transversal. Um grupo de 60 estudantes do terceiro ano respondeu a um questionário autoaplicável composto por 27 perguntas abordando vários aspectos do tratamento endodôntico e 11 áreas-chave dos procedimentos de canal radicular. As opções de resposta para cada questão foram baseadas em uma escala Likert de 4 pontos. A análise dos dados foi realizada utilizando a linguagem de programação Python e mapas de calor foram criados utilizando a biblioteca seaborn para melhor compreender a distribuição dos dados. Resultado: os alunos encontram desafios no desenvolvimento da sensação tátil, na colocação do cone acessório e no alcance preciso do ápice durante a localização do canal. As escolas de odontologia devem se concentrar em melhorar as habilidades táteis e os métodos dos alunos para alcançar o ápice e aumentar a eficácia do ensino sobre tratamento de canal radicular. Em contrapartida, os estudantes relataram menos erros na aplicação do dique de borracha e nas medidas de segurança durante o tratamento. Os educadores odontológicos devem enfatizar o uso adequado dos instrumentos e as precauções de segurança durante o tratamento do canal radicular. Curiosamente, os alunos não consideraram estas áreas problemáticas, apesar de cometerem erros. Conclusão: este estudo fornece informações valiosas sobre os desafios e erros encontrados por estudantes de odontologia durante o tratamento endodôntico. Os educadores odontológicos devem abordar essas questões para melhorar as habilidades e técnicas dos alunos e fornecer o melhor atendimento ao paciente.

Comparison of Accuracy Between Pulp/Tooth Ratio and Tooth Coronal Index Methods for Dental Age Estimation Using Digital Panoramic Radiographs

ABSTRACT Objective: To evaluate the reliability and the accuracy of Tooth Coronal Index (TCI) and Pulp/Tooth Ratio (PTR) methods in dental age estimation using digital panoramic radiography. Material and Methods: In this cross-sectional study, 237 dental panoramic images were collected. The two methods (TCI and PTR) were applied to all left mandibular first and second molars based on inclusion and exclusion criteria. In order to analyze the acquired data, statistical methods were used. The estimated ages derived by exclusive formula were compared to the chronological age, and the error ranges for each indicator were measured to determine their accuracy. Results: There were negative correlations between PTR in the first molar (r=-0.89) and in the second molar (r=-0.788), as well as TCI in the first molar (r=-0.587) and in the second molar (r=-.242). In this study, we found that the Pulp/Tooth Ratio (PTR) accuracy rate for mandibular first and second molar teeth was 79.21% and 62.09 %, respectively, although the Tooth Coronal Index (TCI) value for these teeth was 34.45% and 5.85%. Conclusion: Pulp/Tooth Ratio and Tooth Coronal Index are potential age estimation indices. Although PTR was the more accurate one in our study. The results also demonstrated that indices related to the first molar tooth could be used to estimate age with greater accuracy and validity.

Accuracy of an endodontic rotary motor with integrated apex locator to determine the root canal length / Precisão de um motor rotatório endodôntico com localizador apical integrado para determinação do comprimento radicular

Aim: The purpose of this study was to evaluate the efficacy to determine the root canal length, in vitro,of both the electronic apex locator (M2) and the autostop (AS - M3) functions of the Endus Duo Gnatus endodontic motor (Gnatus, São Paulo, SP, Brazil). Methods: Thirty extracted human single-rooted premolars had their root canal lengths (TLs) up to the apical foramen determined using the Endus Duo Gnatus in two ways: (1) In the stainless steel (SS) control group, the measurement was obtained using a stainless steel hand instrument with the electronic locator mode (M2 function) connected to a stainless-steel hand instrument (K-file #15). In the NiTi rotary instrument (NiTi RI) intervention group, the measurement was obtained during the instrumentation (M3 function) of the root canals with a nickel-titanium rotary instrument (Hyflex CM: Coltene Whaledent, Cuyahoga Falls, OH, USA), size 25/.06. The NiTi manually used instrument (NiTi MUI) Intervention group performed the measurement in locator mode using a Hyflex instrument, placed to true length manually. Statistical analysis was performed using ANOVA followed by the Tukey post-hoc test with a significance level of p < 0.05. Results: The true mean length and standard deviation (SD) of the standardized root canals were 18.40 ± 2.14mm, while the mean lengths and standard deviations (SD) were 18.29 ± 1.89mm, 18.22 ± 1.85mm, and 17.24 ± 2.09mm for the SS, NiTi RI, and NiTi MUI groups, respectively. However, data from the NiTi MUI Intervention group indicated shorter root canal lengths when compared to the SS control group and the NiTi RI Intervention group values, and were significantly shorter than the true canal length (p < 0.001). Conclusions:The use of the motor in NiTi RI Intervention group showed acceptable results. However, the NiTi MUI Intervention group resulted in unacceptable short measurements.

Objetivo: O objetivo deste estudo foi avaliar a eficácia na determinação do comprimento do canal radicular, in vitro, das funções localizador eletrônico foraminal (M2) e auto-parada durante a instrumentação (M3) do motor endodôntico Endus Duo Gnatus ( Gnatus, São Paulo, SP, Brasil). Métodos: Trinta pré-molares humanos uniradiculares extraídos tiveram seus comprimentos de canais radiculares (CRTs) até o forame apical determinados usando o Endus Duo Gnatus de duas maneiras: (1) No grupo controle de aço inoxidável (SS), a medida foi obtida usando um instrumento manual de aço inoxidável com modo de localização eletrônica foraminal (função M2) conectado a um instrumento manual de aço inoxidável (lima tipo K #15). No grupo intervenção instrumento rotatório NiTi (NiTi RI), a medida foi obtida durante a instrumentação (função M3) dos canais radiculares com instrumento rotatório de níquel-titânio (Hyflex CM: Coltene Whaledent, Cuyahoga Falls, OH, EUA), tamanho 25/.06. O grupo de intervenção NiTi instrumento usado manualmente (NiTi MUI) realizou a medição no modo localizador foraminal usando um instrumento Hyflex, colocado manualmente no comprimento real do dente. A análise estatística foi realizada por meio de ANOVA seguida do teste post-hoc de Tukey com nível de significância de p < 0,05. Resultados: Os comprimentos reais médios dos dentes e desvios-padrão (DP) dos canais radiculares padronizados foram 18,40 ± 2,14 mm, enquanto os comprimentos médios e desvios- padrão (DP) foram 18,29 ± 1,89 mm, 18,22 ± 1,85 mm e 17,24 ± 2,09 mm para os grupos SS, NiTi RI e NiTi MUI, respectivamente. No entanto, os dados do grupo de intervenção NiTi MUI indicaram comprimentos de canais radiculares mais curtos quando comparados aos valores do grupo controle SS e do grupo de intervenção NiTi RI, e foram significativamente mais curtos que o comprimento real do canal (p < 0,001). Conclusões: A utilização do motor no grupo Intervenção NiTi RI apresentou resultados aceitáveis. No entanto, o grupo de intervenção NiTi MUI resultou em medições curtas inaceitáveis.

Effect of Glycolic Acid, Maleic Acid, and EDTA in the Removal of Smear Layer from Root Canal Dentin

ABSTRACT Objective: To assess the efficacy of 5% Glycolic Acid (GA), 17% ethylenediaminetetraacetic acid (EDTA) and 7% maleic acid (MA), in removing the smear layer (SL). Material and Methods: For the experiment, forty single-rooted human teeth were selected. To perform the chemo‑mechanical preparation, the root canals were instrumented to an apical size of #30, along with simultaneous irrigation of 2.5% NaOCl. The samples were allotted to the experimental groups based on the final irrigating solution (n=10): (1) The GA group: 05%, (2) the EDTA group: 17%, (3) the MA group: 7%, and (4) the control group: Distilled water. The teeth were evaluated for the presence or absence of SL using SEM. Results: Comparing the 5% GA, 7% MA and 17% EDTA groups, no statistically significant differences were found at the coronal and middle thirds (p>0.05). However, in the apical third, MA had greater efficacy than EDTA (p=0.002) and GA (p=0.041), with a significant difference in the SL removal, while there was no significant difference between the latter (p=0.148). Conclusion: Thus, it was concluded that 7% maleic acid as a final irrigating solution is more efficacious than 17% EDTA and 5% glycolic acid in eliminating the smear layer from the apical portion of the root canal.

Influence of different working lengths on the shaping ability of Reciproc Blue in the apical third and apical foramen: a micro-computed tomographic study

Aim: This study aimed to assess the shaping ability of Reciproc Blue in the apical third and apical foramen of moderately curved canals at different working lengths (WLs), by micro-computed tomography. Methods: Thirty-six mesial roots (mesiobuccal and mesiolingual canals) were included, each with 2 separate root canals and independent apical foramina, according to type IV of Vertucci's classification of first and second mandibular molars. The canals were instrumented at three different WLs: G-1, 1mm short of the major apical foramen; G0, at the major apical foramen; G+1, 1mm beyond the major apical foramen. The groups were assessed for changes in root canal volume and untouched wall area in the apical third. Groups G0 and G+1 were also compared for percentage of untouched walls at the apical foramen. One-way ANOVA (post hoc Tukey test) and Student's t-test adopted a 5% level of significance. Results: Root canal volumes (mm3) in the apical third were 22.86±10.46, 44.48±24.91, and 55.71±21.32 in G-1, G0 and G+1, respectively. G-1 volume following instrumentation increased significantly less than that of G0 or G+1 (P>.05); G0 did not differ from G+1. The percentage of untouched wall area in the apical third did not differ among the three groups (P>.05). G0 and G+1 did not differ regarding untouched walls in the major apical foramem walls. Conclusion: Extending the WL from 1mm short of the apical foramen to a point at and beyond the WL increases the apical third volume without increasing the prepared area. Untouched surface areas of the apical foramen were not modified by instrumentation at or beyond the foramen

Randomized Clinical Study of the Use of MTA and Biodentine™ for Pulpotomy in Primary Teeth

ABSTRACT Objective: To verify, through clinical and radiographic evaluations, the in vivo response of the dentin-pulpal complex of human primary teeth after pulpotomy with MTA and Biodentine™ in a follow-up period of 3, 6, and 12 months. Material and Methods: Thirty teeth were divided into MTA pulpotomy (n = 15) and Biodentine™ pulpotomy (n = 15) from children between 5 and 9 years of age, a randomized clinical trial with simple random sampling. The materials were inserted into the cavity after opening and removing the coronary pulp tissue. The cavity base consisted of glass ionomer cement and light-cured composite resin restoration. Clinical and radiographic analyses were performed after 3, 6, and 12 months. Statistical analysis by Fisher's exact test for dichotomous data at a 5% significance level was utilized. Results: Both materials caused color change after 12 months. However, MTA showed a higher percentage than Biodentine™ (p<0.0001). Pain was detected only with Biodentine™ at six months and mobility at 12 months (p=0.0013). Radiographically, after 12 months, periapical lesions, interradicular lesions, and internal resorption were evidenced in 13% of the cases for Biodentine™-treated teeth (p<0.0013). MTA induced pulp calcification in 13% of cases, unlike Biodentine™ (p<0.0013). Conclusion: BiodentineTM and MTA are suitable for clinical use in pulpotomy treatment, yet both materials lead to tooth discoloration.

Root canal treatment of type Ⅱ and ⅢA double dens invaginatus in maxillary lateral incisor: a case report / 华西口腔医学杂志

Dens invaginatus is a rare developmental anomaly of the teeth that is caused by the infolding of enamel organs or the penetration of their proliferations into dental papillae before calcification has occurred. The presence of double dens invaginatus is extremely rare. This paper describes the use of cone beam computed tomography in the evaluation of a maxillary lateral incisor with double dens invaginatus and periapical periodontitis. The tooth was treated through microscopic root canal therapy. The tooth was free of clinical symptoms, and the periradicular lesion narrowed during the follow-up period of 1 year.

Antibacterial effect of low-temperature plasma on Enterococcus faecalis in dentinal tubules in vitro / 北京大学学报(医学版)

OBJECTIVE@#To construct a model of Enterococcus faecalis (E. faecalis) infection in dentinal tubules by gradient centrifugation and to evaluate the antibacterial effect of low-temperature plasma on E. faecalis in dentinal tubules.@*METHODS@#Standard dentin blocks of 4 mm×4 mm×2 mm size were prepared from single root canal isolated teeth without caries, placed in the E. faecalis bacterial solution, centrifuged in gradient and incubated for 24 h to establish the model of dentinal tubule infection with E. faecalis. The twenty dentin blocks of were divided into five groups, low-temperature plasma jet treatment for 0, 5 and 10 min, calcium hydroxide paste sealing for 7 d and 2% chlorhexidine gel sealing for 7 d. Scanning electron microscopy and confocal laser scanning microscope were used to assess the infection in the dentinal tubules and the antibacterial effect of low-temperature plasma.@*RESULTS@#The results of scanning electron microscopy and confocal laser scanning microscopy showed that after 24 h of incubation by gradient centrifugation, E. faecalis could fully enter the dentinal tubules to a depth of more than 600μm indicating that this method was time-saving and efficient and could successfully construct a model of E. faecalis infection in dentinal tubules. Low-temperature plasma could enter the dentinal tubules and play a role, the structure of E. faecalis was still intact after 5 min of low-temperature plasma treatment, with no obvious damage, and after 10 min of low-temperature plasma treatment, the surface morphology of E. faecalis was crumpled and deformed, the cell wall was seriously collapsed, and the normal physiological morphology was damaged indicating that the majority of E. faecalis was killed in the dentinal tubules. The antibacterial effect of low-temperature plasma treatment for 10 min exceeded that of the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d. These two chemicals had difficulty entering deep into the dentinal tubules, and therefore only had a few of antibacterial effect on the bacterial biofilm on the root canal wall, and there was also no significant damage to the E. faecalis bacterial structure.@*CONCLUSION@#Gradient centrifugation could establish the model of E. faecalis dentin infection successfully. Low-temperature plasma treatment for 10 min could kill E. faecalis in dentinal tubules effectively, which is superior to the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d.

Diversity of root canal morphology in mandibular first premolars and its clinical strategies / 中华口腔医学杂志

It is a basic prerequisite for the successful completion of endodontic treatment to thoroughly understand the root canal space anatomy. With the development of dental devices in dentistry, the root canal morphology of the mandibular first premolars can be presented in more detail. Before conducting root canal therapy on the mandibular first premolar with complex root canal morphology, it should be necessary to evaluate the potential difficulties and risks for making an appropriate treatment plan. The present paper reviews the research progress on the diversities of root canal morphology in mandibular first premolars in recent years, and then makes technologic recommendations based on the morphology diversities.