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.

Classificação e profundidade de istmos em primeiros molares inferiores: estudo retrospectivo em TCFC / Classification and depth of isthmus in mandibular first molars: retrospective CBCT study

O conhecimento da anatomia dental é de extrema importância para o clínico na busca do sucesso endodôntico. Complexidades anatômicas, como os istmos, podem causar dificuldades durante o tratamento, comprometendo a limpeza, antissepsia e posterior obturação. O primeiro molar inferior é o elemento que apresenta maior incidência de istmos em suas raízes e a TCFC é uma poderosa ferramenta para estudo e diagnóstico destas variações anatômicas. O objetivo deste estudo foi avaliar a incidência, classificação e profundidade do istmo na raiz mesial de primeiros molares inferiores, por meio de um banco de dados de tomografias, utilizando o software visualizador e-Vol DX. Foram analisadas 2000 imagens tomográficas obtidas por meio de um tomógrafo Prexion 3D e selecionados 174 primeiros molares inferiores de pacientes com média de idade de 39,5 anos, sendo 86 do sexo masculino e 88 do sexo feminino; as imagens foram analisadas mm a mm, com auxílio dos recursos 3D do software. Os resultados mostraram que 100% dos dentes apresentaram istmos na região cervical em sua raiz mesial, a profundidade mínima encontrada foi de 0,3 mm; em 6,89% das amostras foram observados istmos em todos os cortes ao longo da raiz; a média de profundidade cervical foi de 2,04 mm, não havendo diferenças nos grupos de idade e sexo (p>0,05). O canal mésio-medial foi encontrado em 5,17% das amostras. Seguindo a classificação de Hsu e Kim (1997), ao longo da raiz a maior incidência foi o tipo I (46,90%), seguida do tipo V (25,98%), tipo II (18,22%), tipo IV (7,18%) e tipo III (1,42%). Mais de 83% das amostras apresentaram 3 ou mais tipos de istmo ao longo da raiz; assim, este estudo propôs uma nova classificação baseada na quantidade de variações, sendo que 27,01% foram classificadas como anatomias complexas (4 ou mais tipos na mesma raiz), 56,90% moderadas (3 tipos) e apenas 16,09% simples (até 2 tipos). A TCFC de alta resolução obtida por meio do Prexion 3D, aliada aos recursos do software visualizador e-Vol DX, proporcionaram uma visualização dos istmos com maior clareza.

Avaliação da profundidade da cárie proximal nos exames radiográfico convencional e digitalizado / Evaluation of the size of proximal caries in radiography and digitized

Introdução: A cárie dentária é uma doença multifatorial que compreende vários fatores biológicos e sociais. A superfície proximal dos dentes é uma região de difícil visualização que pode esconder pequenas lesões cariosas no esmalte dentário, impossibilitando o diagnóstico através de inspeções visuais e táteis. Objetivo: O objetivo deste trabalho foi avaliar a profundidade da cárie proximal nos exames radiográficos convencionais e digitais, comparando as profundidades das lesões consideradas nestes exames às do exame histológico. Método: Foram utilizados exames radiográficos interproximais de 40 dentes humanos, 20 pré-molares e 20 molares, com alterações clínicas em uma das superfícies proximais, como lesões de mancha branca ou acastanhada e pequenas cavitações. Três profissionais especializados em radiologia odontológica com mais de cinco anos de experiência clínica mediram a profundidade das lesões pelos exames radiográfico e digital das amostras. Para obter os resultados, utilizou-se a técnica de análise de variância (ANOVA). Resultados: Constatou-se um nível de significância de 5% nas mensurações dos exames radiográficos convencionais e digitalizados, mostrando a fidelidade das imagens radiográficas em relação a real profundidade da lesão. Conclusão: Conclui-se que os exames de imagem avaliados foram eficientes na determinação da profundidade das lesões de cárie proximal.

Introduction: Dental caries is a multifactorial disease that comprises several biological and social factors. The proximal surface of the teeth is a region of difficult visualization that can hide small carious lesions in the dental enamel, making diagnosis through visual and tactile inspection infeasible. Objective: The objective of this study was to evaluate the depth of proximal caries in the conventional and digitized radiographic examinations, comparing the depths of the lesions considered in these examinations to those of the histological examination. Method: Interproximal radiographic examinations of 40 human teeth, 20 premolars and 20 molars, with clinical alterations on one of the proximal surfaces, such as white or brown spot lesions and small cavitations, were used. Three professionals specialized in dental radiology with more than five years of clinical experience measured the depth of the lesions by radiographic examination of the samples. To obtain the results, we used the technique of analysis of variance (ANOVA). Results: A level of significance of 5% was found in conventional and digitized radiographic measurements, showing the fidelity of the radiographic images in relation to the actual depth of the lesion. Conclusion: It was concluded that the imaging tests evaluated were efficient in determining the depth of proximal caries lesions.

Radix em molares decíduos inferiores: revisão sistemática com metanálise / Radix in lower primary molars: systematic review with meta-analysis

Objective: To estimate the prevalence of three roots in deciduous mandibular molars. Methodology: Electronic searches were carried out in PubMed and Scopus to identify cross-sectional studies published up to September 2023. The Joanna Briggs Institute tool was used to critically appraise the studies. STATA 16.0 was used to generate risk of bias figures and perform the meta-analysis. Results: Eighteen studies evaluating 9,067 patients (8,969 first molars and 10,765 second molars) were included in this review. The overall prevalence of radix in mandibular deciduous molars was 9.61% (3.67% for first molars and 18.72% for second molars). The prevalence rate of teeth diagnosed using Cone Beam Computed Tomography (CBCT) was similar to the diagnoses made using conventional radiographic techniques together (periapical, interproximal and panoramic). Final considerations: Lower deciduous molars with three roots have a prevalence of almost 10%, with a higher prevalence in second molars. The diagnosis of this morphological alteration can be made using conventional radiographic techniques, but the use of CBCT is recommended.(AU)

Objetivo: estimar a prevalência de três raízes em molares inferiores decíduos. Metodologia: foram realizadas buscas eletrônicas na PubMed e Scopus para identificar estudos transversais publicados até setembro/2023. Para a avaliação crítica dos estudos foi utilizada a ferramenta do Instituto Joanna Briggs. STATA 16.0 foi usado para gerar figura do risco de viés e realizar a metanálise. Resultados: dezoito estudos que avaliaram 9.067 pacientes (8.969 primeiros molares e 10.765 segundos molares) foram incluídos nesta revisão. A prevalência global de radix em molares decíduos inferiores foi de 9,61% (3,67% para primeiros molares e 18,72% para segundo molares). A taxa de prevalência de dentes com diagnóstico através de Tomografia Computadorizada Cone Beam (TCCB) foi semelhante aos diagnósticos realizados pelas técnicas radiográficas convencionais em conjunto (periapical, interproximal e panorâmica). Considerações finais: os molares decíduos inferiores com três raízes têm uma prevalência de quase 10%, com maior prevalência em segundo molares. O diagnóstico desta alteração morfológica pode ser feito através das técnicas radiográficas convencionais, porém recomenda-se a utilização de TCCB.(AU)

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.

Analysis of the Internal and External Morphology of the Mandibular First Molar in a Chilean Sub-Population Using Cone-Beam Computed Tomography / Análisis de la Morfología Interna y Externa del Primer Molar Mandibular en una Subpoblación Chilena Mediante Tomografía Computarizada de Haz Cónico

SUMMARY: The mandibular first molar (MFM) commonly presents two roots with two canals in the mesial root and one or two canals in the distal root. However, morphological variations have been described in different populations, which must be considered when planning endodontic treatment. The aim of this study was to analyze the internal and external morphology of the MFM in a Chilean sub-population using cone-beam computed tomography (CBCT) images. An in vivo cross-sectional, descriptive, and observational study was conducted using CBCT exams from 351 right and left MFM. The data were analyzed by descriptive statistics using the Chi- Square test for categorical variables, Fisher's exact test, the Mann-Whitney U non-parametric test for two independent samples, and the Wilcoxon non-parametric test for related samples. Of the total sample, 1 root was observed in 2.27 % of the cases, 2 roots in 93.73 %, and 3 roots in 4 %. In relation to the number of canals, 71.23 % of the MFM showed 3 root canals, 16.81 % 4 canals, 9.69 % 2 canals, and 2.28 % 1 canal. Of all the studied cases, 2.3 % had a C-shaped anatomy. In terms of morphology, using Zhang's classification, variant 3 was observed in 71.23 %, variant 4 in 12.82 %, variant 1 in 9.67 %, variant 6 in 4 %, and variant 8 in 2.28 %. In conclusion, the morphology of the MFM is variable in a Chilean sub-population, and these variations must be considered before and during endodontic therapy. CBCT proved to be an effective tool for the in vivo study of tooth morphology.

El primer molar mandibular (MFM) comúnmente presenta dos raíces con dos canales en la raíz mesial y uno o dos canales en la raíz distal. Sin embargo, se han descrito variaciones morfológicas en distintas poblaciones, las que se deben tener en consideración al momento de planificar el tratamiento endodóntico. El objetivo de este estudio fue analizar la morfología interna y externa del MFM en una sub población chilena mediante el uso de imágenes de tomografía computarizada Cone Beam (CBCT). Se realizó un estudio transversal, descriptivo y observacional in vivo empleando exámenes CBCT de 351 MFM tanto derechos como izquierdos. Los datos se analizaron mediante estadística descriptiva empleando la prueba Chi-Cuadrado para variables categóricas, el test exacto de Fisher, la prueba no paramétrica de U-Mann-Whitney para dos muestras independientes y la prueba no paramétrica de Wilcoxon para muestras relacionadas. Del total de la muestra se observó 1 raíz en un 2.27 % de los casos, 2 raíces en 93.73 % y 3 raíces en un 4 %. En relación al número de canales un 71.23 % de los MFM mostraron 3 canales radiculares, un 16.81 % 4 canales, un 9.69 % 2 canales y un 2.28 % 1 canal. Del total de los casos estudiados un 2.3 % se presentó anatomía en forma de C. En relación a la morfología, empleando la clasificación de Zhang, se observó en un 71.23 % la variante tipo 3, en un 12.82 % la variante tipo 4, en un 9.67 % la variante tipo 1, en un 4 % variante tipo 6 y en un 2,28 % variante tipo 8. En conclusión, la morfología del MFM es variable en una subpoblación chilena y estas variaciones deben ser consideradas antes y durante la terapia endodóntica. El CBCT demostró ser una herramienta eficaz para el estudio in vivo de la morfología dentaria.

Exodontia de primeiro molar superior permanente em criança: relato de caso / Clínico maxillary first permanent molar extraction in a child: case report

Entre as perdas precoces de um elemento dental ocorre em grande frequência a do primeiro molar permanente, que normalmente tem o seu irrompimento por volta dos 6 anos de idade, e são propensos a serem acometidos por lesões cariosas que se não cuidadas precocemente pode-se levar a perda do elemento dental. Há também outros agentes que ocasionam a perda do elemento como o trauma de baixa intensidade, tais como, os cálculos dentários, os hábitos bucais deletérios e principalmente a falta de motivação de higiene oral. Diante disto, este trabalho visa a apresentação de um caso clínico de um paciente de 9 anos de idade, sem alterações sistêmicas, com grande destruição coronária no dente 26. Os exames de imagens foram colaboradores para diagnóstico e definição da extração. Foi realizada a exodontia em campo aberto. O paciente foi instruído quanto à higiene bucal e futuramente encaminhado para um tratamento ortodôntico. Conclui-se que o Cirurgião Dentista tem papel fundamental no diagnóstico e tratamento dessas alterações dentais, enfatizando a importância do tratamento restaurador de lesões cariosas precocemente, remoção de qualquer agente irritante de baixa intensidade e na motivação da higiene bucal(AU)

Among the early loss of a dental element, the loss of the first permanent molar occurs very frequently, which usually has its eruption around the age of 6 years, and they are prone to be affected by carious lesions that, if not treated early, can if it leads to loss of the dental element. There are also other agents that cause the loss of the element, such as low-intensity trauma, such as dental calculi, deleterious oral habits and especially the lack of motivation for oral hygiene. Therefore, this work aims to present a clinical case of a 9-year-old patient, without systemic alterations, with great coronary destruction in tooth 26. The imaging exams collaborated for the diagnosis and definition of the extraction. The extraction was performed in an open field. The patient was instructed about oral hygiene and later referred for orthodontic treatment. It is concluded that the Dental Surgeon has a fundamental role in the diagnosis and treatment of these dental alterations, emphasizing the importance of an early restorative treatment of carious lesions, removal of any low-intensity irritant and in the motivation of oral hygiene(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.

Banda ortodôntica como alternativa de tratamento conservador provisório para primeiros molares permanentes com hipomineralização molar incisivo (HMI): relato de caso / Orthodontic banding as an alternative provisional conservative treatment for permanent first molars with incisor molar hypomineralization (IMH): case report

Introdução: a Hipomineralização Molar Incisivo (HMI) é um defeito qualitativo de desenvolvimento de esmalte que pode ocasionar fraturas pós-eruptivas (FPE), lesões de cárie e sensibilidade. Objetivo: relatar o tratamento de HMI severa através da cimentação de bandas ortodônticas para preservação da estrutura dentária em primeiros molares permanentes inferiores com FPE. Relato do caso: criança do sexo feminino, 10 anos de idade, apresentou-se com queixa de hipersensibilidade e fratura dentária associada à restauração prévia. Clinicamente, observou-se presença de HMI severa, com FPE associada à lesão de cárie em dentina nas superfícies oclusal e vestibular do dente 36 e restauração insatisfatória com cimento de ionômero de vidro (CIV) na superfície vestibular do dente 46 que apresentava opacidades demarcadas branco-creme. Radiograficamente, observou-se ausência de comprometimento pulpar. Após manejo por meio de abordagens não-invasivas (controle de biofilme e dieta e aplicação de verniz fluoretado), o tratamento proposto foi a cimentação de banda ortodôntica com CIV modificado por resina (Riva Light Cure®, SDI) nos dentes 36 e 46 para maior longevidade das restaurações. O tratamento restaurador atraumático (TRA) foi realizado no dente 36 previamente à cimentação da banda ortodôntica. Resultados: após o tratamento, a criança não relatou dor ou desconforto e as restaurações mantiveram-se intactas. A mãe da criança foi orientada quanto à importância de acompanhamento periódico a cada 4 meses. Conclusão: a cimentação das bandas ortodônticas com CIV possibilitou o manejo conservador de molares permanentes com HMI severa, com manutenção de sua funcionalidade oclusal, saúde pulpar e gengival, proporcionando melhor qualidade de vida à paciente.

Introduction: molar Incisor Hypomineralization (MIH) is a qualitative developmental enamel defect that can cause posteruptive enamel breakdown (PEB), caries lesions, and sensitivity. Objective: to report the treatment of a child with severe MIH through the cementation of orthodontic bands in lower first permanent molars with PEB to preserve tooth structure. Case report: female child, 10 years old, presenting hypersensitivity complaints and tooth fracture associated with previous restoration. Severe MIH was observed, with PEB associated with dentin caries on the occlusal and buccal surfaces of tooth #36 and unsatisfactory glass ionomer cement (GIC) restoration on the buccal surface of tooth #46 which had creamy-white marked opacities. There was no pulp involvement radiographically. After management through non-invasive approaches (biofilm and diet control and application of fluoride varnish), the proposed treatment was the cementation of an orthodontic band with resin-modified GIC (Riva Light Cure®, SDI) on teeth #36 and #46 to long-term lifespan restorations. Atraumatic restorative treatment (ART) was performed on tooth #36 prior to the cementation of the orthodontic band. Results: after treatment, the child did not report pain or discomfort and the restorations remained intact. The child's mother was instructed about the importance of periodic follow-up visits every 4 months. Conclusion: the cementation of orthodontic bands with GIC allowed the conservative management of permanent molars with severe MIH, maintaining their functional occlusion, pulpal and gingival health, providing a better quality of life to the patient.

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.

Effects of early unilateral mandibular first molar extraction on condylar and ramal asymmetry / Efectos de la extracción temprana del primer molar mandibular unilateral sobre la asimetría condilar y ramal

SUMMARY: Craniofacial symmetry is an important factor in creating a harmonious facial appearance. Genetic and external factors may cause the formation of mandibular asymmetry. The aim of this study was to evaluate vertical mandibular asymmetries in adolescents who had unilateral mandibular first permanent molar (FPM) teeth extracted at an early age. The study group consisted of 60 subjects (30 females, 30 males with a mean age of 16.18±1.04 years) who had their mandibular permanent first molar tooth extracted before the age of 12, and the control group consisted of 60 healthy subjects (30 females, 30 males with a mean age of 16.23±0.92 years). Condylar asymmetry index (CAI), ramal asymmetry index (RAI), and condylar-ramal asymmetry index (CRAI) were calculated using panoramic radiographs of the subjects. Independent samples t-test was used to evaluate the differences between groups. CAI, RAI, and CRAI values were similar between male and female subjects in both control and study groups, and no statistically significant difference was found (p>0.05). No statistically significant difference was observed between the group who had their mandibular first permanent molar teeth extracted at an early age and the control group (p>0.05). CAI values were relatively higher in both groups, but there was no significant difference between the CAI, RAI, and CRAI values between the groups.

La simetría craneofacial es un factor importante para crear una apariencia facial armoniosa. Factores genéticos y externos pueden causar la formación de asimetría mandibular. El objetivo de este estudio fue evaluar las asimetrías mandibulares verticales en adolescentes a quienes se les extrajo el primer molar permanente (FPM) mandibular unilateral a una edad temprana. El grupo de estudio consistió en 60 sujetos (30 mujeres, 30 hombres con una edad media de 16,18±1,04 años) a quienes se les extrajo el primer molar mandibular permanente antes de los 12 años, y el grupo control consistió en 60 sujetos sanos (30 mujeres, 30 hombres con una edad media de 16,23±0,92 años). El índice de asimetría condilar (CAI), el índice de asimetría ramal (RAI) y el índice de asimetría condilar-ramal (CRAI) se calcularon utilizando radiografías panorámicas de los sujetos. Se utilizó la prueba t de muestras independientes para evaluar las diferencias entre los grupos. Los valores de CAI, RAI y CRAI fueron similares entre los hombres y las mujeres tanto en el grupo control como en el de estudio, y no se encontraron diferencias estadísticamente significativas (p>0.05). No se observaron diferencias estadísticamente significativas entre el grupo al que se le extrajo el primer molar permanente mandibular a una edad temprana y el grupo control (p>0,05). Los valores de CAI fueron relativamente más altos en ambos grupos, pero no hubo diferencias significativas entre los valores de CAI, RAI y CRAI entre los grupos.

Evaluation of the occlusal contact area of molar dental implants comparing two different thicknesses (16 µm and 200 µm) of articulating occlusal papers and forces (200 and 250 N): a pivot in vitro study

Introduction: The goal of this pilot study was to evaluate the differences between checking occlusion on implants crowns using 16 or 200 µm thickness of articulating occlusal paper, and to compare the stained occlusal area between the groups after bite forces of 200 and 250 N. Methods: It was included 10 casts of articulated-type IV gypsum, 10 NiCr crowns, articulating occlusal papers (16 µm and 200 µm thick), and a compression test machine. Compressive forces (200 and 250 N.mm) were applied on models, to check the occlusal contact area of fixed and cemented crowns. The contact areas on the crowns were measured through images obtained by the scanning electron microscope. Statistical tests were performed considering the significant level of 5% (p≤0.05). Results: The stains found using 200 µm of articulating paper were higher than those with 16 µm, independent of the force applied. However, the stains obtained in lower teeth with different strengths (200 and 250N) marked with 16 µm articulating paper were not possible to score. The articulating paper variable had significant statistical results (p=0.002), while the variables force (p=0.443) and articulating paper-force interaction (p=0.607) were not significant. The mean area found in staining using the 200 µm and 16 µm papers was, respectively, 8.3380 mm2 and 3.4759 mm2. Conclusion: It was possible to confirm that 200 µm of articulating occlusal paper showed better and significant results to stain the occlusal area, permitting a more accurate adjustment independent of the force applied.

Avaliação do comportamento das fibras colágenas periodontais durante a progressão da periodontite experimental em ratos / Evaluation of the behaviour of periodontal collagen fibers during the progression of experimental periodontitis in rats

Introdução: A periodontite é uma doença infecto-inflamatória, resultante da disbiose microbiana e da resposta do hospedeiro, que leva à destruição dos tecidos de suporte dentário, inclusive das fibras colágenas periodontais, podendo culminar na perda do elemento dental. Objetivo: Avaliar o comportamento das fibras colágenas periodontais durante a progressão da periodontite experimental induzida em ratos. Material e método: Doze ratos Wistar foram distribuídos nos grupos: Controle (C), Periodontite Experimental 14-dias (PE-14d), Periodontite Experimental 21-dias (PE-21d) e Periodontite Experimental 42-dias (PE-42d). No dia 0, os animais do grupo C foram eutanasiados. Neste mesmo dia, os animais remanescentes foram submetidos à instalação de uma ligadura de algodão ao redor do primeiro molar inferior esquerdo para indução da periodontite experimental. Tais animais foram eutanasiados aos 14 (PE-14d), 21 (PE-21d) e 42 (PE-42d) dias após a instalação da ligadura. Executou-se o processamento histológico das hemimandíbulas e as secções foram submetidas à reação histoquímica pelo vermelho picro-sirius. A análise qualitativa descritiva foi realizada sob microscopia de luz polarizada, na região de furca dental, evidenciando as fibras do ligamento periodontal. Resultado: O grupo C exibiu feixes espessos e orientados de fibras colágenas maduras, condizentes com aspecto de normalidade. Os grupos com periodontite experimental exibiram desestruturação tecidual severa, com fibras colágenas imaturas e de menor espessura, sendo tais condições mais exacerbadas nos grupos PE-14d e PE-21d. Conclusão: As fases iniciais da periodontite apresentam caráter agudo e, portanto, resultam na rápida destruição dos tecidos periodontais de suporte, prejudicando potencialmente a fibrilogênese e a reestruturação do colágeno no ligamento periodontal.

Introduction: Periodontitis is an infectious-inflammatory disease resulting from microbial dysbiosis and host response that leads to the destruction of tooth support tissues, including periodontal collagen fibers, which may culminate in tooth loss. Objective: To evaluate the behavior of periodontal collagen fibers during the progression of induced experimental periodontitis in rats. Material and method: Twelve Wistar rats were distributed into groups: Control (C), 14-days Experimental Periodontitis (PE-14d), 21-days Experimental Periodontitis (PE-21d) and 42-days Experimental Periodontitis (PE-42d). At day 0, the animals of group C were euthanized. At the same day, the remaining animals were submitted to the installation of a cotton ligature around the lower left first molar for the induction of experimental periodontitis. The animals were euthanized at 14 (PE-14d), 21 (PE-21d) and 42 (PE-42d) days after the installation of ligature. Histological processing of the hemi-mandibles was performed and the sections underwent histochemical reaction using picro-sirius red. The descriptive qualitative analysis was performed under polarized light microscopy, in the dental furcation region, evidencing the fibers of the periodontal ligament. Result: Group C exhibited thick and oriented bundles of mature collagen fibers, consistent with a normal appearance. The groups with experimental periodontitis exhibited severe tissue disruption, with immature and thinner collagen fibers, with such conditions being more exacerbated in the PE-14d and PE-21d groups. Conclusion: The early stages of periodontitis present acute response, and therefore result in rapid destruction of periodontal support tissues and potentially impair fibrillogenesis and collagen restructuring in the periodontal ligament.

A Comparison between Inferior Alveolar Nerve Block and Crestal Anesthesia in Children Undergoing Dental Extraction Procedure

ABSTRACT Objective: To evaluate the efficacy of crestal anesthesia compared to the inferior alveolar nerve block (IANB) in 6-9-year-old children undergoing tooth extraction. Material and Methods: This case-control study was conducted on 70 children who needed bilateral mandibular primary molar extractions. The Faces Pain Scale was used to determine the efficacy of the anesthetic technique. Demographic data, onset time of anesthesia, duration of anesthesia, and blood pressure were also recorded. The data were analyzed using SPSS 25 and analytical tests: t-test, chi-squared test, and one-way ANOVA. The level of significance was set at p<0.05. Results: The efficacy of the IANB was significantly higher than the crestal anesthesia (p<0.05). The duration of IANB anesthesia was significantly more than the crestal anesthesia (p<0.05). The two anesthetic techniques showed no significant differences in pediatric blood pressure as a determinant of the pain evoked in children during the injection (p>0.05). Conclusion: Crestal anesthesia proved an effective method to extract primary molars. However, further studies are necessary to confirm this.

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.

Prevalence and extent of Alveolar dehiscence and fenestration in Class I hyperdivergent subjects with different buccolingual inclinations of maxillary molar teeth: a CBCT study

Buccolingual position of teeth could affect the prevalence of alveolar bone defects. Presence of alveolar defects may have a deleterious effect on orthodontic treatment. The aim was to assess the prevalence and extent of dehiscence and fenestration in Class I hyperdivergent subjects and correlate it with buccolingual inclinations(BL) of maxillary first molar teeth. Methods: This retrospective study involved 80 CBCTs of class I hyperdivergent subjects divided into two groups - group A (n=33) buccolingual inclination >9º and group B (n=47) buccolingual inclination <9º. Prevalence and extent of alveolar bone dehiscence and fenestrations were measured in CBCTs using OSIRIX Lite software. Descriptive statistics, Mann Whitney U test and Spearman correlation were done for evaluating intergroup differences and correlation with Buccolingual inclination. Results: Overall prevalence of dehiscence and fenestration in maxillary first molars was 60.95% and 5% respectively. In the buccal alveolar bone, prevalence of dehiscence was highest in group A (84.6%) for 16 and in the lingual alveolar bone prevalence of dehiscence was highest in group B (71.4%) for 26 . On intergroup comparison, the extent of lingual alveolar bone dehiscence (26) in group B was significantly higher (p value <0.05) than in group A. No significant correlation between the extent of dehiscence and fenestration with buccolingual inclination of molar teeth was noted. Conclusion: Molar teeth with BL inclinations of more than 9º had higher prevalence of dehiscence on the buccal side and molar teeth with BL inclinations less than 9 degrees had more dehiscence on the lingual side. But no significant correlation of BL inclination with prevalence and extent of dehiscence and fenestration was noted

Prevalence of Dental Fear and its Association with Painful Oral Conditions in Adolescents

ABSTRACT Objective: To estimate the prevalence of dental fear and evaluate its association with dental caries and with Molar Incisor Hypomineralization (MIH) in schoolchildren aged 11-14 years. Material and Methods: A cross-sectional study was conducted with 375 adolescents in Campina Grande, Brazil. Socioeconomic and oral health information was collected, while dental fear was measured using the Children's Fear Survey Schedule-Dental Subscale (CFSS-DS). The diagnosis of dental caries and MIH was performed by three trained examiners (κ ≥ 0.61) using the International Caries Detection & Assessment System - ICDAS II and a previously validated index, respectively. Data were descriptively analyzed using the Chi-Square, Fisher's Exact, and Poisson regression tests with robust variance (p<0.05). Results: The prevalence of dental fear was 18.4%, and the mean CFSS-DS total score was 28.96 ± 8.92. After adjusting for covariates family structure, schooling of parents/guardians, type of dental health service and dental pain in the last six months, the prevalence of dental fear was associated with dental pain in the last six months (PR=2.03; 95%CI=1.31-3.16; p=0.002). Conclusion: Although no association was found between dental fear, dental caries and MIH in adolescents, those who experienced dental pain in the last six months had a higher prevalence of dental fear.

Combined micro-apical surgery and vital pulp therapy in mandibular second molars with external root resorption caused by impacted teeth / 华西口腔医学杂志

OBJECTIVES@#This study aimed to establish a new treatment of the mandibular second molars with external root resorption caused by impacted teeth to preserve the affected teeth and their vital pulps.@*METHODS@#For mandibular second molars clinically diagnosed as external root resorption caused by impacted teeth, debridement and removal of the root at the resorption site via micro-apical surgery and direct capping of the pulp with bioactive material on the surface of the root amputation via vital pulp therapy were performed immediately after the impacted teeth were extracted.@*RESULTS@#The external root resorption of the affected tooth was ceased. It was asymptomatic with intact crown, normal pulp, periapical alveolar bone reconstruction, normal periodontal ligament, continuous bone sclerosis, and no periapical translucency in radiographic examination at the 1-year postoperative follow-up, thus showing good prognosis.@*CONCLUSIONS@#Simultaneous combination of micro-apical surgery and vital pulp therapy after extraction of impacted teeth could successfully preserve mandibular second molars with ERR caused by impacted teeth and their vital pulps.

Clinical diagnosis and treatment of furcation involvement / 中华口腔医学杂志

Furcation involvement (FI) is the lesion and destruction of periodontium that spread to the root furcation of multi-root teeth, where periodontal pockets, loss of periodontal attachment and resorption of alveolar bone are formed. Furcation involvement is a common concomitant lesion of periodontitis. The severity of furcation involvement can directly affect the prognosis of periodontitis. However, the specificity of the anatomical structure of the root furcation greatly increases the difficulty of treatment. Therefore, early detection and treatment of furcation involvement is crucial for the prevention and control of periodontitis. This paper briefly describes the pathogenesis of furcation involvement and discusses the diagnosis, classification and treatment of this disease, which is helpful to improve the clinical diagnosis and treatment of furcation involvement.

X-ray evaluation of pulp calcification in adult permanent teeth after pulpotomy / 北京大学学报(医学版)

OBJECTIVE@#To compare the clinical effects of pulpotomy with two kinds of calcium silicate materials, and to evaluate the formation of dentin bridge and pulp calcification after pulpotomy of adult permanent teeth.@*METHODS@#Patients who visited the General Department of Peking University School and Hospital of Stomatology from November 2017 to September 2019 and planned for pulpotomy on permanent premolars and molars with carious exposed pulp were selected. They were randomly divided into two groups. Bioceramic putty material iRoot BP (iRoot group, n=22) and mineral trioxide aggregate MTA (MTA group, n=21) were used as pulp capping agents, respectively. The patients were recalled after one year and two years. The clinical efficacy, dentin bridge index (DBI) and pulp calcification index (PCI) were recorded. Blinding method was used for the patients and evaluators.@*RESULTS@#There was no significant difference in gender, mean age, dentition and tooth position between the two groups (P>0.05). Seven cases were lost during the first year (4 cases in iRoot group and 3 cases in MTA group). In the iRoot group, 1 case had transient sensitivity at the time of 1-year follow-up. The cure rate of the two groups was 100% at the time of 2-year follow-up. The proportion of dentin bridge formation was 38.9% one year after operation, 55.6% two years after operation. The proportion of partial or even complete disappearance of root canal image was 5.6% before operation, 38.9% and 55.6% one and two years after operation, respectively. The difference was statistically significant by rank sum test (P < 0.05). There was no significant difference in dentin bridge formation and pulp calcification between the two groups (P < 0.05). DBI and PCI after operation was as the same as those before operation (44.4% cases of DBI and 25% cases of PCI) or gradually increased (55.6% cases of DBI and 75% cases of PCI). Spearman's nonparametric correlation analysis showed that age was positively correlated with preoperative pulp calcification index (PCI0, P < 0.05), but not with the dentin bridge index (DBI1, DBI2), pulp calcification index (PCI1, PCI2) and the degree of change (DBI2 vs. DBI1, PCI1 vs. PCI0, PCI2 vs. PCI0) 1-year and 2-year after operation (P>0.05).@*CONCLUSION@#According to this study, good clinical effects were obtained within 2-year after pulpotomy of adult permanent teeth with MTA and iRoot. In some cases, the root canal system had a tendency of calcification aggravation, and there was no statistical difference in the development of this trend between the two groups.