Reabsorción radicular en premolares, posterior a ortodoncia de autoligado, utilizando tomografía computarizada

Este Estudio tuvo por objetivo determinar la incidencia de reabsorción radicular externa en premolares superiores e inferiores permanentes al finalizar el tratamiento de ortodoncia. Esta investigación fue realizada en pacientes entre 18 y 35 años que recibieron tratamiento de ortodoncia, sin extracciones, con técnica de autoligado en la ciudad de Guadalajara. Se consideraron 120 premolares, realizando mediciones longitudinales en las tomografías computarizadas de haz cónico al inicio y término del tratamiento. Utilizando el software Implant Viewer 3. Los valores registrados en el primer y segundo premolar superior tanto del lado derecho como izquierdo al inicio y término del tratamiento fluctuaron entre -4.946 y -7.801; p ≤ 0.0005 encontrándose diferencias estadísticas significativas. Mientras que en el primer y segundo premolar inferior tanto del lado derecho como izquierdo, fluctuaron entre -4.864 y -5.28; p ≤ 0.0005 encontrándose diferencias estadísticas significativas. Se concluye en este estudio que los dientes sometidos a movimientos durante el tratamiento de ortodoncia sufren modificaciones en el contorno de la raíz, cambios con consecuencias mínimas que no comprometen la funcionalidad del diente. Los premolares superiores presentaron mayores rangos de reabsorción radicular que los premolares inferiores.

The aim of this study is to determine the incidence of root resorption in permanent upper and lower premolars at the end of an orthodontic treatment. This research was carried out in patients aged between 18 and 35 years old who received orthodontic treatment, without extractions, with a self-ligating technique in the city of Guadalajara, Mexico. In this study, 120 premolars were considered, making longitudinal measurements with cone beam computed tomography at the beginning and the end of the treatment, using the Implant Viewer 3 software. The values recorded in the upper first and second premolars on both the right and left sides at the beginning and the end of the treatment fluctuated between -4.946 and -7.801; p ≤ 0.0005, finding statistically significant differences. In the lower first and second premolars on both the right and left sides, they fluctuated between -4.864 and -5.28; p ≤ 0.0005, also finding statistically significant differences. It is concluded that teeth subjected to movements during orthodontic treatment suffer modifications in the contour of the root, changes with minimal consequences that do not compromise their functionality. The upper premolars showed higher ranges of root resorption than the lower premolars.

Métodos predictivos del espacio mesiodistal de caninos y premolares

Introducción: El análisis más utilizado por los ortodoncistas para predecir el espacio ideal del canino y premolares es el Gold Standard de Tanaka-Johnston. Sin embargo, la utilización de este análisis en otros grupos poblacionales a nivel mundial puede ser cuestionable. Objetivo: Predecir el espacio ideal para la erupción del canino y premolares utilizando el análisis de Tanaka y Johnston y el de Ramos, et al. Material y métodos: Fue un estudio descriptivo. Se utilizaron 110 pares de modelos de estudio con dentición permanente, recolectados durante 2018 y 2019. Los anchos mesiodistales fueron medidos con un vernier digital marca UBERMANN® con una precisión de ± 0,01 mm. A los datos obtenidos se les realizó estadística no paramétrica mediante la prueba de comparación de Kruskal-Wallis. Resultados: El análisis de Tanaka-Johnston mostró una diferencia entre los valores predictivos y reales de -0,50 mm (±1,68) con una diferencia estadística de p=0,0001 y el análisis de Ramos, et al., fue de -0,35 mm (±1,70) con una diferencia estadística de p=0,0001. Conclusiones: Se subestimó el espació ideal para la erupción del canino y premolares con el análisis de Tanaka-Johnston y el análisis validado por Ramos, et al. Sin embargo, el análisis de Ramos, et al., se acercó más a los diámetros mesiodistales reales del canino y premolares.

Introduction: The analysis most commonly used by orthodontists to predict the ideal space of the canine and premolars is the Tanaka-Johnston Gold Standard. However, the use of this analysis in other population groups worldwide may be questionable. Objective: To predict the ideal space for the eruption of the canine and premolars using the Tanaka-Johnston analysis and that of Ramos, et al. Material and Methods: A descriptive study was carried out using 110 pairs of study models with permanent dentition, collected during the period from 2018 to 2019. The mesiodistal widths were measured with a UBERMANN® digital vernier with an accuracy of ± 0.01 mm. Non-parametric statistics were performed on the data obtained using the Kruskal-Wallis comparison test. Results: The Tanaka-Johnston analysis showed a difference between the predictive and real values ​​of -0.50 mm (±1.68) with a statistical difference of p=0.0001, and the Ramos et al. analysis was of -0.35 mm (±1.70) with a statistical difference of p=0.0001. Conclusions: The ideal space for the eruption of the canine and premolars was underestimated with the Tanaka-Johnston analysis and the analysis validated by Ramos, et al. However, the Ramos, et al. analysis was closer to the actual mesiodistal diameters of the canine and premolars.

Tratamiento de diente evaginado mediante técnica de apexificación: reporte de caso / Treatment of dens evaginatus by apexification technique: a case report

El diente evaginado (DE) es una anomalía del desa-rrollo que se define como un tubérculo o protube-rancia que se extiende desde la superficie oclusal del diente afectado. La fractura o desgaste de esta pro-longación, internamente compuesta por tejido pul-par, puede causar diversas enfermedades pulpares, como pulpitis, necrosis pulpar e incluso dar lugar a una periodontitis apical. En el presente caso clíni-co se muestra el tratamiento de DE en un segundo premolar superior izquierdo que presentaba como diagnóstico necrosis pulpar y absceso alveolar cró-nico. El tratamiento consistió en realizar la terapia endodóntica con técnica de apexificación empleando BiodentineTM (AU)

Dens evaginatus (DE) is a dental developmental defect defined as a tubercle or protuberance that extends from the occlusal surface of the affected tooth. Fracture or wear of this extension, internally composed of pulp tissue, can cause diverse pulp diseases, such as pulpitis, pulpal necrosis and it can even induce apical periodontitis.The following clinical case shows the treatment of DE in a maxillary left second premolar diagnosed with pulp necrosis and chronic alveolar abscess. The treatment of choice was endodontic therapy using BiodentineTM (AU)

Estudio de la morfología de los conductos radiculares de los primeros premolares superiores en tomografía computarizada de haz cónico / Study of the morphology of root canals of the first upper premolars in cone beam computed tomography

Objetivo: analizar, mediante tomografía computarizada de haz cónico (TC o CBCT [Cone Beam Computed Tomograph]) la frecuencia del tipo de morfología interna de los conductos radi- culares según la clasificación de Vertucci y el número de raíces de los primeros premolares superiores. Material y métodos: en una población argentina de 50 pacientes, 30 de sexo femenino y 20 masculino, que concurrieron a la Cátedra de Diagnóstico por Imá- genes de la Facultad de Odontología de la Universidad de Buenos Aires, se evaluaron 100 primeros premolares superiores con CBCT. Se estudiaron las variables: número de raíces, tipo de morfología interna, edad, sexo y lado. Fueron seleccionadas las tomografías de maxilar superior que incluyeron ambos primeros premolares en salud dental, periodontal y con ápice cerrado. Se realizó una adquisición volumétrica 100 × 90 mm y tamaño de vóxel de 150 µm. Se realizó la exploración de las imágenes en el plano axial de los tercios apical, medio y cervical de las piezas 1.4 y 2.4. Se utilizó un corte axial, observando en él, el tercio apical, medio y cervical de las piezas 1.4 y 2.4. Cada premolar fue analizado con 30 cortes transversales. Se utilizó la clasificación de Vertucci para agrupar las distintas variables anatómicas de los conductos radiculares de los primeros premolares superiores, la cual consta de VIII tipolo- gías. Resultados: el tipo más representativo entre los 100 primeros premolares superiores, dentro de la clasificación de Vertucci, fue el tipo IV (dos conductos separados desde la cámara al ápice). La coincidencia de tipos entre los lados derecho (78%; IC 95%: 65 a 87%) e izquierdo (70%; IC 95%: 56 a 81%) fue significativa. La distribución según el número de raíces en el lado derecho (χ 2 = 2.88) e izquierdo (χ2 = 0.72) no presentó una heterogeneidad significativa. La coincidencia del número de raíces entre los lados derecho e izquierdo fue significativa. Conclusión: se comprobó el tipo de morfología interna más frecuente, el número de raíces y su variabilidad de acuerdo al lado, sexo, y edad; lo cual es de una relevante importancia para realizar una correcta instrumentación y obturación del sistema de conductos radiculares (AU)

Objective: to analyze, using cone beam computed tomography (CBCT), the frequency of the type of internal morphology of the root canals according to the Vertucci classification and the number of roots of the first upper premolars. Material and methods: 100 first upper premolars were evaluated with CBCT, which corresponded to 30 female and 20 male patients in the Chair of Diagnostic Imaging of the Faculty of Dentistry, University of Buenos Aires. Variables were studied: number of roots, type of internal morphology, age, sex and side. The tomography of the upper jaw with both first premolars in dental, periodontal and closed apex health, a 100 × 90 mm volumetric acquisition and a voxel size of 150 µm were selected. An axial cut was used, observing the apical, middle and cervical third of pieces 1.4 and 2.4. Each premolar was analyzed with 30 paraxial cuts. The Vertucci classification was used to group the different anatomical variables of the root canals of the first upper premolars which consists of VIII typologies. Results: the most representative type among the top 100 upper premolars within the Vertucci classification was type IV (two separate ducts from the chamber to the apex). The type coincidence between the right (78%; 95% CI: 65 to 87%) and left (70%; 95% CI: 56 to 81%) los primeros premolares superiores, la cual consta de VIII tipolo gías. Resultados: el tipo más representativo entre los 100 primeros premolares superiores, dentro de la clasificación de Vertucci, fue el tipo IV (dos conductos separados desde la cámara al ápice). La coincidencia de tipos entre los lados derecho (78%; IC 95%: 65 a 87%) e izquierdo (70%; IC 95%: 56 a 81%) fue significativa. La distribución según el número de raíces en el lado derecho (χ 2 = 2.88) e izquierdo (χ2 = 0.72) no presentó una heterogeneidad significativa. La coincidencia del número de raíces entre los lados derecho e izquierdo fue significativa. Conclusión: se comprobó el tipo de morfología interna más frecuente, el número de raíces y su variabilidad de acuerdo al lado, sexo, y edad; lo cual es de una relevante importancia para realizar una correcta instrumentación y obturación del sistema de conductos radiculares (AU))

Root canal morphology of 1316 premolars from Brazilian individuals: an in vivo analysis using cone-beam computed tomography / Morfologia do canal radicular de 1.316 pré-molares de indivíduos brasileiros: análise in vivo usando tomografia computadorizada de feixe cônico

ABSTRACT The aim of this study was to investigate the internal root canal anatomy of maxillary and mandibular premolars in a Brazilian subpopulation, in order to establish the prevalence of the different configurations proposed by Vertucci. Three hundred and ninety-eight cone-beam computed tomography scans were collected from a private imaging clinic database in Rio de Janeiro, including 217 maxillary and 226 mandibular scans. A total 1316 premolars (594 maxillary and 722 mandibular) were evaluated using an image viewer, and classified according to Vertucci. Two calibrated examiners determined the frequency of each morphological Type. A third examiner reviewed discordant cases. The Kappa test was applied to verify inter-rater agreement, and Fisher's Exact Test to verify gender-related differences. The most frequent root canal configurations of maxillary first and second premolars were Type IV (73.86%) and Type I (47.18%), respectively. Type I was the most prevalent in mandibular first and second premolars (80.59% and 95.86%, respectively). Only Types I and VIII presented a statistically significant difference between sexes. Type I was more frequent in females and Type VIII in males. A highly significant frequency of Type I was found in both mandibular first and second premolars, whereas the most frequent maxillary premolar root canal configuration was Type IV for first premolars and Type I for second premolars.

RESUMO O presente estudo teve como objetivo investigar a anatomia interna de pré-molares superiores e inferiores em uma subpopulação brasileira para estabelecer a prevalência das diferentes configurações propostas por Vertucci. Trezentos e noventa e oito exames de tomografia computadorizada de feixe cônico foram coletados de um banco de dados de uma clínica privada de imagem no Rio de Janeiro, incluindo 217 exames maxilares e 226 mandibulares. Um total de 1.316 pré-molares (594 superiores e 722 inferiores) foram avaliados usando um visualizador de imagens e categorizados de acordo com a classificação de Vertucci. Dois examinadores calibrados determinaram a frequência de cada tipo morfológico. Um terceiro examinador revisou os casos discordantes. O teste Kappa foi aplicado para verificar a concordância entre os avaliadores e o Teste Exato de Fisher para verificar diferenças relacionadas ao gênero. A configuração do canal radicular mais frequente dos primeiros e segundos pré-molares superiores foi Tipo IV (73,86%) e Tipo I (47,18%), respectivamente. O tipo I foi o mais prevalente nos primeiros e segundos pré-molares inferiores (80,59% e 95,86%, respectivamente). Os tipos I e VIII foram os únicos que apresentaram diferença estatisticamente significativa entre os sexos. O tipo I foi mais frequente nas mulheres e o tipo VIII nos homens. Uma frequência altamente significativa do Tipo I foi encontrada em ambos os primeiros e segundos pré-molares inferiores, enquanto a configuração do canal radicular dos pré-molares superiores mais frequente foi o Tipo IV para os primeiros pré-molares e o Tipo I para os segundos pré-molares.

Endodontic reintervention of a mandibular second premolar with four root canals: a case report / Reintervención endodóntica de un segundo premolar mandibular con cuatro conductos radiculares: reporte de caso / Reintervenção endodôntica de um segundo pré-molar mandibular com quatro condutos radiculares: relato de caso

Abstract Complex anatomical variations on root canals morphology are one of the most arduous challenges in the endodontic practice. The objective of this case report is to discuss the clinical management of a mandibular left second premolar with four root canals and four distinct apical foramina. This case report has been written according to Preferred Reporting Items for Case reports in Endodontics (PRICE) 2020 guidelines. A 74-year-old patient was referred to retreat a left mandibular second premolar. The patient complained of discomfort when chewing hard food. After obtaining consent from the patient to investigate the symptoms, a thorough clinical and radiographic examination was performed. The main clinical findings observed were a moderate sensitivity to vertical percussion and mild discomfort at palpation. The periapical radiograph showed a fusion-like root with multiple canals and unsatisfactory root canal fillings associated with apical radiolucency. Based on this investigation, a diagnostic of persistent apical periodontitis was made to the tooth, and nonsurgical root canal re-treatment was proposed to the patient. After written informed consent was obtained, the procedure was performed under magnification provided by a dental operating microscope with the aid of ultrasonic tips. During the access opening and fillings removal, four root canal orifices were observed. Therefore, state-of-the-art technology such as the dental operating microscope, ultrasonics, and cone-bean computed tomography image are strong allies to manage anatomical variations.

Resumen Las complejas variaciones anatómicas en la morfología de los conductos radiculares son uno de los desafíos más arduos en la práctica de la endodoncia. El objetivo de este reporte de caso es discutir el manejo clínico de un segundo premolar mandibular izquierdo con cuatro conductos radiculares y cuatro agujeros apicales distintos. Este informe de caso se ha escrito de acuerdo con Preferred Reporting Items for Case reports in Endodontics (PRICE) 2020. Paciente de 74 años que fue remitido para retirada de un segundo premolar mandibular izquierdo. El paciente se quejaba de malestar al masticar alimentos duros. Después de obtener el consentimiento del paciente para investigar los síntomas, se realizó un examen clínico y radiográfico completo. Los principales hallazgos clínicos observados fueron una sensibilidad moderada a la percusión vertical y una leve molestia a la palpación. La radiografía periapical mostró una raíz similar a una fusión con múltiples conductos y empastes de conductos radiculares insatisfactorios asociados con radiolucidez apical. Con base en esta investigación, se realizó un diagnóstico de periodontitis apical persistente en el diente y se propuso al paciente un nuevo tratamiento del conducto radicular no quirúrgico. Una vez obtenido el consentimiento informado por escrito, el procedimiento se realizó con un aumento proporcionado por un microscopio quirúrgico dental con la ayuda de puntas ultrasónicas. Durante la apertura del acceso y la remoción de los empastes, se observaron cuatro orificios del conducto radicular. Por lo tanto, la tecnología de punta, como el microscopio de operación dental, los ultrasonidos y la imagen de tomografía computarizada de haz cónico, son fuertes aliados para manejar las variaciones anatómicas.

Resumo Variações anatômicas complexas na morfologia dos canais radiculares são um dos desafios mais árduos na prática endodôntica. O objetivo deste relato de caso é discutir o manejo clínico de um segundo pré-molar inferior esquerdo com quatro canais radiculares e quatro forames apicais distintos. Este relato de caso foi escrito de acordo com as diretrizes do Preferred Reporting Items for Case reports in Endodontics (PRICE) 2020. Um paciente de 74 anos foi encaminhado para retirada de um segundo pré-molar inferior esquerdo. O paciente queixou-se de desconforto ao mastigar alimentos duros. Após obter o consentimento do paciente para investigar os sintomas, foi realizado um exame clínico e radiográfico completo. Os principais achados clínicos observados foram sensibilidade moderada à percussão vertical e leve desconforto à palpação. A radiografia periapical mostrou uma raiz fusionada com múltiplos canais e obturações de canais radiculares insatisfatórias associadas à radioluscência apical. Com base nesta investigação, um diagnóstico de periodontite apical persistente foi feito ao dente, e um retratamento não cirúrgico do canal radicular foi proposto ao paciente. Após a obtenção do termo de consentimento livre e esclarecido, o procedimento foi realizado sob magnificação fornecida por microscópio cirúrgico odontológico com auxílio de pontas de ultrassom. Durante a abertura do acesso e retirada das obturações, foram observados quatro orifícios do canal radicular. Portanto, tecnologia de ponta, como microscópio cirúrgico odontológico, ultrassom e imagem de tomografia computadorizada de feixes cônico, são fortes aliados para o gerenciamento de variações anatômicas.

Resistencia adhesiva de postes de fibra a los diferentes tercios del conducto radicular / Adhesive resistance of fiber posts to different thirds of the root canal

En los últimos años resulta de elección la utilización de postes de fib ra en la rehabilitación de piezas endodónticamente tratadas. La adhesión entre poste, agente cementante y dentina radicular permitiría lograr una retención de la estructura dentro de las paredes del conducto. El objetivo de este estudio fue comparar la resistencia adhesiva en los tercios cervical, medio y apical, entre la dentina del conducto radicular y el cemento adhesivo utilizado en la cementación de postes de fibra. Se utilizaron 30 premolares inferiores uniradiculares humanos, recientemente extraídos, se realizaron los tratamientos endodónticos, se desobturaron y realizaron las preparaciones con la fresa conformadora número 3 para la cementación de postes White Post DC especial número 3 con cemento Paracore utilizando el protocolo adhesivo del mismo sistema. Las muestras fueron incluidas en acrílico cristal, cortadas en forma perpendicular al eje mayor de la pieza con una máquina de corte y por último se procedió a medir los valores de adhesión de los postes a la superficie interna de los conductos en los tres tercios con la prueba push-out mediante una máquina de ensayo universal. Los resultados arrojaron que las resistencias (media +- DE, MPa) en los tercios cervical, medio y apical, fueron 8,74 +- 3,12, 9,38 +- 2,29 y 11,11 +- 2,95, respectivamente. En el tercio apical se registró mayor resistencia. Considerando las limitaciones de esta investigación, se puede concluir que la cementación de postes de fibra con cementos resinosos, presenta mayores valores en el tercio apical y menores en el tercio cervical del conducto radicular con técnica de Push-out (AU)

Permanent Maxillary Premolars With Three Canals- A Case Report

Maxillary first premolar is a bi-rooted tooth with several variations in the root canal morphology. Usually it has 2 canals, however at times there could be an additional third canal present which could easily be missed by the clinician owing to lack of awareness and knowledge about the canal variations. Awareness of internal and external anatomy of tooth and also about its variations are essential for successful endodontic therapy. Prevalence of three canals in maxillary premolar is very low. This case report describes the endodontic management of permanent maxillary premolars with three root canals.

Assessment of maxillary premolar region in relation to maxillary sinus floor and buccal bone plate: a cone beam computed tomography study / Evaluación de la región premolar maxilar en relación con el piso del seno maxilar y la tabla osea vestibular: estudio de tomografía computarizada de haz cónico

The maxillary sinus floor location and the buccal bone plate are factors to be considered in the long-term success with implant treatments mainly in the premolar region. the aim of this study was to establish morphometric characteristics of the buccal cortical bone (BCB) thickness of maxillary premolars and its relation to maxillary sinus floor through CBCT. In this study 350 first and second maxillary premolars were analyzed from 110 CBCT images and the buccal cortical bone (BCB) was measured in a coronal view at the major axis level of each premolar. In addition, in 200 first and second maxillary premolars CBCT images were measured the distance from premolar apex to maxillary sinus floor (MSF) in both frontal and sagittal plane. The type of relationship between the apex and MSF was classified according to Ok et al. (2014). The second premolar was observed with higher values of BCB (p<0.001). In first premolar, higher values were observed in the male sex (p>0.05). In second premolar, only significantly higher values were observed in the male sex in MA-MB-MC (p>0.05). Regarding to MSF and its relation to premolar roots, it was observed that 10 % of the sample was classified as type I, 19 % as type II, 55.5 % as type III and 15.5 % as type IV. The BCB of the upper premolar region is thicker in the apical region and decreases toward the coronal region. Almost 50 % of apex of second premolars are closely and risky related MSF (Type I and II).

La localización del piso del seno maxilar (PSM) y la tabla ósea vestibular (TOV) son factores a considerar en el éxito a largo plazo de los tratamientos de implante dental en la región premolar. El objetivo de este estudio fue establecer características morfométricas del grosor de la TOV en los premolares maxilares y su relación con el PSM a través de CBCT. Se analizaron 350 primeros y segundos premolares en 110 CBCT y la TOV fue medida en vista coronal en el eje axial mayor de cada premolar. Además en 200 primeros y segundos premolares maxilares se midió la distancia desde el ápice del diente hasta el PSM en el plano sagital y frontal. El tipo de relación entre el ápice y el PSM se clasificó según Ok et al. (2014). El Segundo premolar obtuvo los mayores valores de grosor de TOV (p<0.001). En primeros premolares se observaron valores altos en el género masculino (p>0.05). En segundos premolares solo se encontraron valores significativamente altos en el género masculino en MA-MB-MC (p>0.05). En la relación con el PSM y ápices de raíces de premolares, el 10% de la muestra se clasificó como tipo I, el 19% como tipo II, el 55,5% como tipo III y el 15.5% como tipo IV. En conclusión la TOV de la región premolares superior es más grueso en la zona apical, decreciendo hacia la zona coronal. Alrededor del 50% de los ápices de raíces de premolares maxilares están cercanas y en relación de riesgo con el PSM (tipo I y II).

Root canal anatomy of maxillary second premolars at various ages observed by cone-beam CT / 中华口腔医学杂志

Objective@#To observe the morphological changes of root canals in maxillary second premolars at various ages by using cone-beam CT (CBCT) in order to provide imaging and theoretical reference for clinical treatments.@*Methods@#The digital CBCT data of the maxillary second premolars in 440 cases from the patients in Department of Stomatology, The First Affiliated Hospital, Jinan University during March 2011 and December 2017 were collected. The CBCT images were divided into 4 groups according to the patients′ ages: groups ≤20, 21-40, 41-60 and>60 years old, respectively. Changes of morphologies of root canals with aging including such parameters as types of the root canal, incidence of double root canals in single rooted teeth, distance between both root canal orifices of double rooted canals, and morphological change of the cross section of roots. Chi-square test and liner trend test were adopted in statistical analysis in the present study.@*Results@#Most maxillary second premolars had only one root [95.2% (419/440)]. Type Ⅰ of the root canals was the most common type [57.3% (252/440)], and the following prevalent groups were type Ⅱ[16.8% (74/440)], type Ⅳ [10.2% (45/440)] and type Ⅲ [8.9% (39/440)]. The distribution of type Ⅰ~Ⅳ of the root canals were significantly different amongst various aged groups (P<0.05). Along with aging, the percentages of type Ⅰ decreased while type Ⅱ increased. However, there were no remarkable changes of type Ⅲ and type Ⅳ observed. The incidence of double canal in single rooted teeth gradually increased with aging especially in 20-year-old and above groups, e.g. 13.1% (13/99) in group of ≤20 years old and 45.0% (86/191) in group of 21-40 years old. However, there was no significant increase observed after the age of 40. The distance between two root canal orifices of double rooted canals became shorter with aging except in groups of 40-year-old and above. The morphologies of the cross sections of root canals in most groups were flat shaped [57.8% (1 121/1 938)] and oval shape [31.3% (607/1 938)]. Along with aging, the percentage of circular shape gradually increased while flat and oval shapes decreased.@*Conclusions@#The morphology of root canal could be clearly showed by the CBCT images. Most maxillary second premolars had only one root and one apical foramen. Along with aging, the morphology of the root canals became more and more complicated.

Management of angle class I malocclusion with severe crowding and bimaxillary protrusion by extraction of four premolars: A case report

@#Crowding and protrusion are some of the most common dental cases worldwide. The patient was a 20-year-old female who consulted for severe crowding, protrusion, and deep bite. Clinical examination and cephalometric measurement showed Class I skeletal and proclined incisor. Two step retraction technique was used to correct the condition. Management of tooth tissue discrepancy by the extraction of four premolars is one of the options in the treatment of crowding.

Relación entre el piso del seno maxilar y las raíces de las piezas posteriores superiores, mediante tomografía computada / Relationship between maxillary sinus floor and the posterior upper teeth roots, by means of computed tomography

Objetivo: El objetivo de este estudio fue evaluar la frecuencia con que las raíces de premolares y molares superiores se encuentran dentro del seno maxilar. Conocer la relación entre dichas estructuras es importante para planificar los procedimientos endodónticos y quirúrgicos a ser realizados en esa región. Materiales y métodos: Se realizó el análisis cualitativo dinámico de 82 tomografías computadas de haz cónico (CBCT) unilaterales, analizándose 738 raíces correspondientes a premolares y molares de una sola hemiarcada superior. Se utilizó sala con iluminación controlada y la observación fue realizada por un solo examinador. El criterio de inclusión requería que la cortical inferior del seno maxilar debía ser visible para poder establecer la relación. Se utilizaron los tres planos tomográficos de visualización, permitiendo ajustes de brillo y contraste. La escala de clasificación de cada raíz consideró su relación como: dentro o fuera del seno maxilar. Los datos obtenidos fueron sometidos a las pruebas de Chi-cuadrado y Test Exacto de Fisher. Resultados: el primer premolar superior mostró una proyección hacia el interior del seno maxilar significativamente menor que las otras piezas dentarias posteriores (p>0.05), observándose su raíz vestibular sin proyección. La raíz palatina del primer premolar superior mostró la mayor incidencia dentro del seno maxilar, con un 39,02% del total de las raíces analizadas (p<0,05). El segundo molar superior mostró considerable proximidad con el seno maxilar, pero con menor incidencia con relación a la raíz palatina del primer molar. Conclusión: los procedimientos endodónticos o quirúrgicos a realizarse en cercanía al seno maxilar deben considerar siempre la relación raíz/seno, para evitar maniobras que lo invadan. La raíz palatina del primer molar superior mostró la mayor incidencia dentro del seno maxilar, con un 39,02% (AU)

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

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

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

Сross-sectional anatomic study of direct positional relationships between mandibular canal and roots of posterior teeth using cone beam computed tomography

Objectives: to establish the frequency of the various types of direct contacts of the root apices with the wall of the mandibular canal and to determine gender differences in number of such contacts in a selected belarusian population using cone beam computed tomography. methodology: one hundred and two cone beam computed tomography scans were analyzed to classify the types of contact and three-dimensional relationship between the mandibular teeth and the mandibular canal. results: the direct contact between the teeth and the mandibular canal was observed in 63.7 percent of patients. overall 300 roots of 189 teeth were in direct contact with the mandibular canal: 9.3 percent were second premolars, 14.7 percent were first molars, 33.8 percent were second molars and 50.0 percent were third molars. there were no statistically significant differences in the number of teeth with direct contact with the mandibular canal between males and females. conclusion: the direct contact of the root apices with the mandibular canal was most often found in the second and third molars. the root apices of the third molars had the greatest variability of location relatively to the mandibular canal.

Morphology of the physiological apical foramen of maxillary premolars / Morfología del foramen apical de premolares maxilares

SUMMARY: The purpose of this study was to determine the shape and diameter of the physiological foramen in maxillary premolars of a Chilean population. The sample consisted of 125 extracted maxillary premolars, in which the apical three to five millimeters were cut and observed under magnification of 40x, photographed (Motic Cam), and analyzed using Motic Images Plus 2.0 ML in order to obtain measurements of the minor and major diameter of each physiological foramen. The average minor and major diameter in maxillary premolars was 0.270 and 0.413 mm, respectively. In terms of shape, 72.19 % had oval shaped physiological foramen; 18.93 % were irregularly shaped and 8.88 % were round. Oval and irregular canals are significantly more difficult to shape and require special attention in order to obtain a thoroughly disinfected root canal system.

RESUMEN: El objetivo del estudio fue determinar la forma y el diámetro del foramen fisiológico de premolares maxilares en una población Chilena. La muestra consistió en 125 premolares maxilares extraídos, a los que se cortó de 3 a 5 milímetros apicales, fueron observados bajo magnificación de 40x, fotografiado (Motic Cam) y analizados utilizando Motic Images Plus 2.0 ML para obtener las mediciones de el diámetro menor y mayor de cada foramen fisiológico. El promedio del diámetro menor y mayor en premolares maxilares fue de 0,270 y 0,413 mm respectivamente. En cuanto a la forma 72,19 % tenía el foramen fisiológico de forma oval; 18,93 % tenía forma irregular y 8,88 % fue redondo. Canales ovales e irregulares son significativamente más difíciles de conformar y requieren especial atención para obtener una adecuada desinfección del sistema de canales radiculares.

Current situation of clinical research on impacted premolars / 华西口腔医学杂志

Teeth impaction is a common developmental malformation in oral diseases. Impacted teeth are usually the canines, third molar, central incisors, premolars, and second molars. The prevalence of impaction of maxillary canines and mandibular wisdom teeth is higher than that of other teeth. Most recent studies have focused on the canines and third molars, but research on impacted premolars is limited. In clinical practice, the majority of orthodontic patients require premolar extraction. Thus, impacted premolars play important roles in orthodontic design and prognosis. This article provides an overview of recent research on impacted premolars and summarizes epidemiological features, localizations, and treatments, with the aim of guiding practitioners on orthodontic design and therapy.

Third molars and premolars extraction in conventional orthodontics and in treatments based on maxillary bone remodeling with temporary anchorage: indications and care

ABSTRACT A bone is an anatomic structure in constant remodeling, with different, mutant and wonderfully inconstant designs. With every new and immediate functional demand, there are changes in cortical thickness, trabecular bone density and also in direction and size of trabeculae. Bones' non-stopping search is for adjusting to the functions induced by forces and movements required by a certain life style. Conventional orthodontic planning or with temporary anchorage based on bone remodeling takes into consideration the spaces that are - or may be - occupied by the teeth, in the formation of a functional and esthetic dental arch for the patient. In case it is necessary to extract a tooth and the options are the third molars, partially or totally unerupted, and teeth that belong to other dental groups, obviousness recommends - due to mouth anatomy and physiology, as well as pathologic reasons - extracting the third molars, due to of the several reasons described in the present study.

RESUMO O osso é uma estrutura anatômica em constante remodelação, com designs diferentes, mutantes e maravilhosamente inconstantes. A cada nova e imediata demanda funcional, mudam a espessura das corticais, a densidade do trabeculado, a direção e o tamanho das trabéculas. A busca incessante do osso é para se adequar às funções induzidas pelas forças e movimentos decorrentes do modo de viver. O planejamento ortodôntico convencional ou com ancoragem transitória baseada na remodelação óssea leva em consideração os espaços que os dentes ocupam, ou podem ocupar, na formação de uma arcada dentária funcional e estética para o paciente. Se for necessário extrair algum dente e houver a opção entre os terceiros molares, parcial ou totalmente não irrompidos, e os dentes de outros grupos dentários, a obviedade recomenda - por conta da anatomia e fisiologia bucal, assim como por razões patológicas - optar pela extração dos dentes do siso, pelos várias motivos que serão descritos no presente trabalho.

Cone-beam computed tomography analysis of the canal shaping ability with ProTaper Universal, ProTaper Next and M3 in preparation of curved root canals / 天津医药

Objective To evaluate the shaping ability of ProTaper Universal (PU), ProTaper Next (PN) and M3 in preparation of curved root canals by CBCT (cone-beam computed tomography). Methods Sixty extracted maxillary first premolars were divided into two groups according to the canal curvature:10°-25° group and 26°-75°group. Then, each group was divided into PU group, PN group and M3 group and prepared with three instruments respectively. Canals were scanned by CBCT scanner before and after preparation. The efficacy of canal preparation was analyzed. The width of dentine removed was measured at three points (2 mm, 5 mm and 8 mm to root tip). The apical transportation indexes and the centring ratio values were recorded. Results PN group and M3 group needed less time in preparation and showed more efficiency than those of PU group in 26°-75° groups. One of root canals in PU group appeared deformation, neither PN group nor M3 group appeared deformation after 5 root canal preparations in average. None instrument was broken in three groups. PU group removed more materials at internal walls than PN group and M3 group at internal walls of root canals in 5 mm from the apex. There was no difference in the offset of the external walls of root canals. Compared with the offset of the internal and external walls of root canals in 2 mm from the apex, the apical transportations prepared by the PN group were less than those of M3 group and PU group in 26°-75° groups. Compared with the offset of the internal and external walls of root canals in 5 mm from the apex, the apical transportations prepared by the PN group and M3 group were less than those of PU group, and their centring ratio values were greater than those of PU group in 26°-75°groups. Conclusion ProTaper Next and M3 tested in this study are effective and time-saving in shaping curved root canals. The results indicate that both ProTaper Next and M 3are comparable to optimally enlarge root canal.

Evaluation of root and canal morphology of mandibular premolars in urban Indian population: an in-vivo cone beam computed tomographic study.

Background: Inability to recognize anatomical variations in roots and canal configurations remains one of the principal factors in failure of endodontic therapy. Mandibular premolars, due to their varied internal morphology, present an endodontic challenge more often than other teeth. Objective: To assess the root morphology and canal configuration of mandibular first and second premolars using three-dimensional cone-beam computed tomography imaging (3D CBCT). Methodology: Bilaterally, mandibular premolars were evaluated on 100 CBCT images independently by two experienced endodontists. Vertucci’s classification was used to identify and divide the canal configurations. Results: 97% of first premolars and 99.5% of the second premolars were found to have one root. The most common canal configuration was found to be Type- I. Other types of canal configurations were 5.5% and 5% in first and second premolars respectively. Conclusions: Modern-day endodntist needs to be vigilant at all times to avoid missing canals and consequent failures.

Morfometría de premolares mandibulares en radiografías panorámicas digitales: análisis de curvaturas radiculares / Morphometric study of mandibular premolars in panoramic digital radiographs: analysis of root curvatures

El objetivo de este trabajo fue describir el grado y orientación de la curvatura radicular en premolares mandibulares, e identificar el tercio radicular en el que la curvatura se origina, mediante el uso de radiografías panorámicas y morfometría lineal. También se detectó la prevalencia de curvaturas radiculares excesivas o dilaceraciones. Se desarrolló un estudio de corte transversal y la muestra consistió en 477 radiografías panorámicas digitales tomadas durante el año 2014 en un centro radiográfico universitario. Se aplicaron criterios de exclusión tanto para radiografías como para los dientes y de esta manera se incorporaron al estudio 118 radiografías (76 mujeres y 42 hombres) y un total de 294 premolares. A partir del análisis de las muestras, se registró el grado y orientación de curvaturas (mesial o distal), el tercio radicular en el que la curvatura se originó y la prevalencia de dilaceraciones. De los dientes curvados, el ángulo promedio de la curvatura fue de 19,68°. Se encontró que 12,24% de los premolares tienen curvatura con orientación mesial, 58,84% tienen orientación distal y 28,92% son rectos. Del total de curvaturas, el 0,48% se originaron en el tercio cervical, 27,27% en el tercio medio y 72,25% en el tercio apical. Una asociación estadísticamente significativa fue encontrada entre el tipo de diente y la orientación de la curvatura (p= 0,025) y entre el tercio del diente en que se originó la curvatura y la orientación de ésta (p= 0,000). Respecto a los premolares mandibulares, tienen curvaturas radiculares en el 72,09% (ángulo promedio: 13,9°). La mayoría de las curvaturas se originaron en el tercio apical (72,25%). La prevalencia de las dilaceraciones fue de 0% o 30,27%, según distintos criterios. A partir de los resultados obtenidos en nuestra investigación consideramos que el conocimiento de la anatomía radicular de los dientes es de importancia antes de la ejecución de procedimientos en endodoncia, ortodoncia y otras áreas, para realizar una planificación adecuada de estas prácticas odontológicas.

The aim of this study was to describe the degree and orientation of root curvature in mandibular premolars and to identify the radicular third in which the curvature originates, using digital panoramic radiographs and linear morphometry. We also aimed to detect the prevalence of excessive root curvatures or dilacerations. A cross-sectional study was developed and were included 477 digital panoramic radiographs taken during 2014 at a university radiologic center. Exclusion criteria were applied to both radiographs and teeth, so that, 118 radiographs (76 women, 42 men) and a total of 294 premolars were included in the study. From the analysis of the samples, we registered the degree of curvature, the curvature orientation (distal or mesial), the part of the root in which the curvature originates, and the prevalence of dilacerations. In curved teeth, the average angle of the curvature was 19.68°. It was found that 12.24% of the premolars have mesial orientation curves, 58.84% have distal orientation curves, and 28.92% were straight. Of the total number of curvatures, 0.48% originated in the radicular cervical third, 27.27% in the middle third, and 72.25% in the apical third. A statistically significant association was found between tooth type and orientation of the curvature (p= 0.025) and between the tooth third in which the curvature originates and the orientation of the curvature (p= 0.000). In respect to mandibular premolars, 72.09% have root curvatures (average angle: 13.9°). Most curvatures originate in the apical third (72.25%). The prevalence of dilacerations was 0% to 30.27% according to different criteria. From the results of our research we believe that knowledge of the anatomy of the tooth root is important before performing procedures in endodontics, orthodontics and other areas, for a proper planning of these dental practices.