Quiste radicular residual / A residual radicular cyst

En la región cervicofacial los quistes de los maxilares de origen odontogénico constituyen una afección relativamente importante, los más frecuentes son los quistes radiculares. Se presentó un paciente masculino de 23 años de edad con un quiste radicular residual extenso que ocupaba la zona mandibular posterior izquierda, y acude a consulta estomatológica de la Clínica «Celia Sánchez Manduley» por un aumento de volumen que causa asimetría facial notable de la hemicara izquierda, de tres centímetros de diámetro, indoloro, asintomático, con 6 meses de evolución y consistencia dura; además refiere tratamiento de exodoncia de molar inferior en la zona (37) hace 2 años. Se indicó radiografía periapical y panorámica donde se observó zona radiolúcida bien definida de 35 a 38 con reabsorción de raíz mesial de 38, distal de 36 y movilidad dentaria grado II en ambos dientes. Se realizó exéresis de la lesión cuyo estudio histológico informó un quiste radicular residual.

Jaw cysts of odontogenic origin constitute a relatively important condition in the cervicofacial region, where radicular cysts are the most frequent. We present a 23-year-old male patient who come to "Celia Sánchez Manduley" Dental Clinic with an extensive residual radicular cyst that occupied his left posterior mandibular area and an increase in volume that caused him a notable facial asymmetry in the left side of his face, of three centimeters in diameter, painless, asymptomatic, with 6 months of evolution and hard consistency; he also mentions a lower molar extraction treatment in area (37) 2 years ago. Periapical and panoramic X-rays were indicated where a well-defined radiolucent zone of 35 to 38 was observed with mesial root resorption of 38, distal of 36 and grade II dental mobility in both teeth. Exeresis of the lesion was performed, whose histological study reported a residual radicular cyst.

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.

Has the literature thoroughly categorized the lower third molars? A new classification of the various lower third molar root forms for a better understanding of their morphology / ¿La literatura ha categorizado minuciosamente los terceros molares inferiores? Una nueva clasificación de las diversas formas radiculares del tercer molar inferior para una mejor comprensión de su morfología

SUMMARY: Impacted lower third molars (IL3M) have different root shapes and numbers. This study aimed to create a classification for IL3M root forms, that should aid in understanding roots morphology. A retrospective cross-sectional study on patients had IL3M at the university clinics between 2017 and 2019. Panoramic radiographs were retrieved to classify the roots into fused roots (FR): one or two roots connected from furcation to apices, and separated roots (SR): two or more roots not connected from furcation to apical third, and each type has different forms. Statistical analysis was done by Chi-Square test. Five-hundred patients, males (54.6 %) and females (45.4 %) were included. SR were in 591 teeth (75.5 %), and FR in 192 teeth (24.5 %). Statistically significant associations emerged between SR and males (60 %) and between FR and females (66 %) (p = .000). SR forms were straight (45.8 %), joined roots (28.2 %), one straight and one curved (13.3 %), roots curved distal (9.1 %), roots curved mesial (2.5 %), and more than two roots (0.3 %). FR forms were straight (87.5 %), curved distal (9.4 %), S-shaped (2.1 %), and curved mesial (1 %). The common angulations of IL3M with SR were vertical (39 %) followed by mesioangular (25.7 %), while FR were mostly vertical (39.1 %) or horizontal (23.9 %). The classification is applicable on panoramic radiographs, and complements Winter and Pell & Gregory to provide a better description of IL3M status by adding root morphology to the angulation, occlusal, and ramus relationship.

Los terceros molares inferiores impactados (3MII) tienen diferentes formas y números de raíces. Este estudio tuvo como objetivo crear una clasificación para las formas de raíz 3MII, que debería ayudar a comprender la morfología de las raíces. Realizamos un estudio transversal retrospectivo de pacientes con 3MII en las clínicas universitarias entre 2017 y 2019. Se recuperaron radiografías panorámicas para clasificar las raíces en raíces fusionadas (RF): una o dos raíces conectadas desde la zona de furca a los ápices y raíces separadas (RS): dos o más raíces no conectadas desde la bifurcación al tercio apical, y cada tipo con formas diferentes. El análisis estadístico se realizó mediante la prueba Chi-Cuadrado. Se incluyeron 500 pacientes, hombres (54,6 %) y mujeres (45,4 %). RS se observó en 591 dientes (75,5 %) y RF en 192 dientes (24,5 %). Surgieron asociaciones estadísticamente significativas entre RS y hombres (60 %) y entre RF y mujeres (66 %) (p = .000). Las formas de RS eran rectas (45,8 %), raíces unidas (28,2 %), una recta y una curva (13,3 %), raíces curvas distales (9,1 %), raíces curvas mesiales (2,5 %) y más de dos raíces (0,3 %).). Las formas RF eran rectas (87,5 %), curvas distales (9,4 %), en forma de S (2,1 %) y curvas mesiales (1 %). Las angulaciones comunes de 3MII con RS fueron verticales (39 %), seguidas de mesioangular (25,7 %), mientras que RF fueron mayoritariamente verticales (39,1 %) u horizontales (23,9 %). La clasificación es aplicable en radiografías panorámicas y complementa a Winter y Pell & Gregory para proporcionar una mejor descripción del estado de 3MII al agregar la morfología de la raíz a la relación de angulación, oclusal y rama.

Success and survival rates of immediate anatomic zirconia implants: a prospective clinical and radiographic evaluation

Modern immediate titanium implants have two major drawbacks which are the black metal appearance that might be seen through the mucosa and the gap between implant and extraction socket. Immediate anatomical zirconia implants were introduced to match the shape of the extracted root and fill the socket without gaps while still providing better metal-free appearance. Aim: This study aims to investigate success and survival rates of immediate anatomical zirconia implants. Methods: This prospective interventional study was held between 2017 and 2020 in the faculty of dental medicine, Damascus University, Syria. The sample consisted of 27 immediate anatomical zirconia implants in 21 patients from both genders. Implants were designed and manufactured starting from CBCT image and prior to extraction. Specialized software applications were used to modify implant design. Implants went through different processing procedures to make them ready for insertion immediately after tooth extraction. Restorations were made after a minimum period of 3 months, clinical and radiographic follow ups were performed after 10 - 13.5 months from restoring the implants in order to evaluate their success/ survival. Repeated measures ANOVA was used to assess marginal bone loss, t test for probing depth assessment. Results: Immediate anatomical zirconia implants showed success in (n=17) 63% of total cases, satisfactory survival (n=3) 11.1%, compromised survival (n=2) 7.4% and they failed in (n=5) 18.5%. Conclusions: Immediate anatomical zirconia implants had low success/survival rates when compared to conventional immediate implants. Therefore, they cannot be considered as a predictable alternative in their current form

Effect of intracanal diode laser irradiation on fracture resistance of roots restored with CAD/CAM posts

Aim: To evaluate the fracture resistance of roots restored with CAD/CAM-fabricated posts, receiving or not intracanal laser treatment, compared with glass fiber posts under mechanical cycling. Methods: Twenty-seven endodontically treated, single-rooted teeth were divided into 3 groups: group 1 (control), prefabricated glass fiber posts relined with resin composite; group 2, CAD/CAM-fabricated intraradicular posts using Resin Nano Ceramic (RNC) blocks; and group 3, CAD/CAM-fabricated intraradicular posts using RNC blocks in canals irradiated with a 940-nm diode laser (100 mJ, 300-um optic fiber, coronal-apical and apical-coronal helical movements, speed of 2 mm/second, 4 times each canal). After cementation of the coping, cyclic loading was applied at an angle of 135° to the long axis of the root, with a pulse load of 130 N, frequency of 2.2 Hz, and 150,000 pulses on the crown at a point located 2 mm below the incisal edge on the lingual aspect of the specimen. Every 50,000 cycles, the specimens were evaluated for root fracture occurring below or above the simulated bone crest. Results were analyzed by one-way ANOVA followed by Tukey's test (p<0.05). Results: Group 1 was the least resistant, while groups 2 and 3 were the most resistant. Group 1 differed significantly from groups 2 and 3 (p<0.01), but there was no difference between groups 2 and 3 (p<0.01). Conclusion: Treatment of the intracanal surface with diode laser had no influence on fracture resistance of roots restored with CAD/CAM-fabricated posts, but a longer cycling time is required to evaluate the real benefits of diode laser irradiation

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))

Lesiones perirradiculares asociadas a primeros molares superiores tratados endodónticamente: estudio a través de tomografías computadas / Periradicular lesions associated with endodontically treated maxillary first molars: study through computed tomography

Objetivos: Estudiar con tomografías computadas de haz cónico (CBCT) las lesiones perirradiculares de primeros molares superiores tratados endodónticamente; evaluar la lo- calización y, en los que tenían lesión en la raíz mesiovestibu- lar (MV), evaluar la frecuencia del conducto MV2. Materiales y métodos: A partir de una muestra de 179 tomografías, que incluían primeros molares superiores, se seleccionaron y analizaron aquellas en las cuales estos ha- bían recibido un tratamiento endodóntico previo, presentaban lesiones perirradiculares y conservaban una restauración co- ronaria. Las variables analizadas fueron: la localización de áreas radiolúcidas compatibles con lesiones perirradiculares de origen endodóntico y la correlación entre diferentes loca- lizaciones y la calidad del tratamiento realizado (adecuado, defectuoso o sin tratamiento). Los datos fueron analizados mediante la prueba de chi-cuadrado y la prueba de Spearman. Resultados: De las 179 CBCT que incluían primeros molares superiores, 90 reunían las condiciones requeridas. La frecuencia de las lesiones perirradiculares fue significativa- mente mayor en la raíz MV al compararla con las raíces disto- vestibular y palatina (p<0,05). El conducto MV1 presentó un tratamiento adecuado en todos los casos. El conducto MV2 recibió un tratamiento adecuado en 4 casos (4,44%), defec- tuoso en 4 casos (4,44%) y no tratado en 82 casos (91,1%); con una diferencia estadísticamente significativa (p<0,05). Conclusiones: En la muestra analizada, la localización de lesiones perirradiculares postratamiento endodóntico en primeros molares superiores se encontró con mayor frecuencia asociada a la raíz mesiovestibular, donde en la mayoría de los casos el con- ducto MB2 no fue tratado o presentó un tratamiento defectuoso (AU)

Aim: To study with cone-beam computed tomography (CBCT) the periradicular lesions of maxillary first molars with endodontical treatment; to evaluate its localization and, in those with a mesiobuccal root (MB) injury, assess the fre- quency of the MB2 root canal. Materials and methods: From a sample of 179 tomog- raphies (CBCT) that included maxillary first molars, those in which they had received previous endodontic treatment, pre- sented periradicular lesions and had a coronary restoration were selected and analyzed. The analyzed variables were: localization of radiolucent areas compatible with periradic- ular lesions of endodontic origin and the correlation between different localizations and quality of the performed treatment (adequate, defective, or untreated). Data were analyzed by the chi-square test and the Spearman test. Results: Of the 179 CBCT that included maxillary first molars, 90 met the required conditions. The frequency of periradicular lesions was significantly higher in the MB root when compared with distobuccal and palatal roots (P<0,05). The MB1 canal presented an adequate treatment in all cas- es. The MB2 canal received adequate treatment in 4 cases (4.44%), a defective one in 4 cases (4.44%) and was untreated in 82 cases (91.1%). The differences among these frequencies were statistically significant (P<0.05). Conclusions: In the analyzed sample, the localization of periradicular lesions after endodontic treatment in maxillary first molars was associated more frequently with the mesio- buccal root in which in the majority of cases the MB2 canal was untreated or presented a defective treatment

Incidencia de fracturas dentales verticales reportadas en la Ciudad de Chihuahua y su relación con la evolución de la pandemia por COVID-19 / Incidence of vertical dental fractures reported in Chihuahua City and its relationship with the evolution of the COVID-19 pandemic

Durante la pandemia por COVID-19, la presencia de un incremento de fracturas y/o fisuras verticales ha sido reportada por Cirujanos Dentistas en diferentes países y foros, Objetivo: Determinar por medio de un análisis si existe una relación con este aumento de casos y la evolu- ción de la pandemia. Material y método: Se recopilaron los casos de fracturas verticales no restaurables durante el periodo de mayor índice de casos de contagio y defunciones por COVID-19 en la Ciudad de Chihuahua, México. Resultados: Durante el primer pico de casos y defunciones causadas por la pandemia, se incrementó el número de casos de fracturas verticales no tratables. Conclusiones: Existió una relación entre la evolución de la pandemia con la aparición de casos de fracturas dentales verticales no restaurables (AU)

During the COVID-19 pandemic, the presence of an increase in fractures and/or vertical fissures has been reported by Dental Surgeons in different countries and forums. Objective: To determine through an analysis, if there is a relationship with this increase in cases and the evolution of the pandemic. Material and methods: The cases of non-restorable vertical fractures were collected during the period of highest rate of cases of contagion and deaths due to COVID-19 in the City of Chihuahua, Mexico. Results: during the 1st peak of cases and deaths caused by the pandemic, the number of cases of untreatable vertical fractures increased. Conclusions: There was a relationship between the evolution of the pandemic and the appearance of cases of non-restorable vertical dental fractures (AU)

Retratamiento y reparación de una perforación radicular. Informe clínico, radiográfico e histológico / Retreatment and healing of a case of root perforation. Clinical, radiographic and histological report

Objetivo: Describir los aspectos clínicos, radiográfi- cos e histológicos del retratamiento realizado en un segundo molar superior en el que se había producido previamente una perforación radicular durante el tratamiento original. Caso clínico: Un paciente masculino de 50 años con- currió a la consulta para realizar un retratamiento endodóntico en un segundo molar superior derecho. El examen radiográfi- co reveló la presencia de un tratamiento incompleto, un área radiolúcida periapical y una perforación radicular producida por un poste roscado insertado fuera del espacio del conducto mesio vestibular. Una vez retirado el poste, se selló la perfo- ración con Biodentine y se realizó el retratamiento. Luego de dos años, el paciente regresó a la consulta con dolor a la mas- ticación, localizado en el área correspondiente al segundo mo- lar superior derecho previamente tratado. Durante el examen clínico y radiográfico se detectó la presencia de una fractura vertical en la raíz palatina. A causa del severo compromiso radicular el molar fue extraído y derivado para su análisis his- tológico. El informe del laboratorio reveló que la perforación había sido reparada por medio de la aposición de un nuevo tejido calcificado y que el remanente periodontal adherido a la raíz se encontraba dentro de los límites normales. El presente caso clínico resalta la importancia que tiene el conocimiento cabal de la anatomía del sistema de conductos radiculares con el objeto de evitar errores de procedimiento que puedan influir negativamente en el pronóstico del tratamiento (AU)

Aim: To describe the clinical, radiographic and histo- logical aspects of the retreatment of a second upper molar in which root perforation had occurred during the original treatment. Clinical case: A 50-year old male was referred for endo- dontic retreatment of the right second maxillary molar. Radi- ographic examination revealed the presence of an incomplete root canal treatment, a radiolucent periapical area and a root perforation produced by a threaded post placed outside of the mesiobuccal root canal. After post removal, the root perfo- ration was sealed with Biodentine and the root canals were retreated. Two years later, the patient returned to the office com- plaining of severe pain during mastication, in the area of the previously retreated right second maxillary molar. Clinical and radiographic examination revealed the presence of a ver- tical fracture on the palatal root. Since this kind of root dam- age non-restorable, the tooth was extracted and submitted to histologic analysis. The laboratory report revealed that the perforation site had healed by the apposition of new calci- fied tissue, and that the remnants of periodontal tissue which persisted attached to the root were within normal limits. This clinical case highlights the importance of thorough knowl- edge of the anatomy of the root canal system in order to avoid procedural errors which may compromise the prognosis of the treatment (AU)

Prevalence of radix entomolaris in mandibular first molars by cone-beam computed tomography in a southern Chilean sub-population / Prevalencia de radix entomolaris en primeros molares mandibulares usando tomografía computarizada cone-beam en una subpoblación del sur de Chile

SUMMARY: The aim of this of this study was to evaluate the prevalence and morphology of radix entomolaris (RE) in the mandibular first molar (MFM) in a southern Chilean sub-population by cone-beam computed tomography (CBCT). Two hundred ten CBCT images of MFM were analysed. To detect the presence of RE, the observation and measurements were standardised, advancing 1 mm to apical from the floor of the pulp chamber to the most apical zone of the tooth. The data were analyzed using descriptive statistics, with a value of P < 0.05 being statistically significant. The prevalence of a third root in the permanent MFM was 5.7 % (12/210). The incidence of RE was the same in male patients (2.9 %) as in female patients (2.9 %) (p=0.324). The occurrence of an RE in the left MFM was 7.3 % (3/41 patients) for male patients and 4.5 % (3/66) for female patients (p=0.398). The right MFM in male patients had an incidence of 8.1 % (3/37) and 4.5 % (3/66) for female patients (p=0.340). When the presence of an RE was compared between the left (5.6 %) and right side (5.8 %), no statistically significant differences were found (p=0.998). The frequency of bilateral three-rooted MFM was 71.43 % (5/7) and 28.57 % (2/7) were unilateral. The prevalence of RE in MFM in a southern Chilean sub-population was 5.7 %. The occurrence was bilateral in the majority of cases and no significant differences were observed by sex or side. The commonest type of RE was Type 1 (83.3 %). The use of CBCT can improve the endodontic treatment outcome.

RESUMEN: El objetivo de este estudio fue evaluar la prevalencia y morfología de radix entomolaris (RE) en el primer mo- lar mandibular (MFM) en una subpoblación del sur de Chile mediante tomografía computarizada de haz cónico (CBCT). Se analizaron doscientas diez imágenes CBCT de MFM. Para detectar la presencia de OD se estandarizó la observación y las medidas, avanzando 1 mm apical desde el suelo de la cámara pulpar hasta la zona más apical del diente. Los datos fueron analizados mediante estadística descriptiva, siendo estadísticamente significativo un valor de P < 0,05. La prevalencia de una tercera raíz en el MFM permanente fue de 5,7 % (12/210). La incidencia de ER fue la misma en pacientes masculinos (2,9 %) que en pacientes femeninas (2,9 %) (p=0,324). La aparición de un ER en el MFM izquier- do fue del 7,3 % (3/41 pacientes) para los pacientes masculinos y del 4,5 % (3/66) para las pacientes femeninas (p=0,398). El MFM derecho en pacientes masculinos tuvo una incidencia de 8,1 % (3/ 37) y 4,5 % (3/66) para pacientes femeninos (p=0,340). Cuando se comparó la presencia de un OD entre el lado izquierdo (5,6 %) y derecho (5,8 %), no se encontraron diferencias estadísticamente significativas (p=0,998). La frecuencia de MFM de tres raíces bilaterales fue 71,43 % (5/7) y 28,57 % (2/7) fueron unilaterales. La prevalencia de RE en MFM en una subpoblación del sur de Chile fue de 5,7 %. La presentación fue bilateral en la mayoría de los casos y no se observaron diferencias significativas por sexo o lado. El tipo de ER más frecuente fue el tipo 1 (83,3 %). El uso de CBCT puede mejorar el resultado del tratamiento endodóntico.

Relationship between root canal merging and presence of C-shaped canal in fused rooted maxillary molar teeth / Relação entre a fusão do canal radicular e a presença de canal em forma de C em dentes molares maxilares fundidos e enraizados

Objective: This study aimed to evaluate the prevalence of root fusion and the incidence of C-shaped canals in maxillary first molar (MFM) and maxillary second molar (MSM) teeth using cone-beam computed tomography. Material and Methods: In this study, a total of 1233 MFMs and 1406 MSMs from 802 patients were analyzed. First, the number of fused rooted teeth and the type of root fusion were determined. Subsequently, incidence and number of C-shaped canals were ascertained according to the type of fusion, location, position, and level of canal merging in teeth with fused roots. Six types were established according to the C-shape configurations observed. Presence of root fusion and the C-shaped canal according to gender, age, and tooth position were evaluated by chi-square test. Values with p< 0.05 were considered significant in statistical tests. Results: The incidence of fusion in the MFM and MSM teeth was 6.16% and 22.40%, respectively. Only three MFMs (0.24%) and 3.77% of the MSMs had C-shaped canals. While the incidence of fusion was higher in women (p< 0.05), the C shaped morphology was not affected by sex (p> 0.05). Individuals over the age of 50 years had a lower incidence of C-shaped canals (p< 0.05). Conclusion: C-shaped canal morphology was more commonly associated with complex types of root fusion involving three roots; 16.83% of MSMs with fused roots had C-shaped canals (AU).

Objetivo: o objetivo deste estudo foi avaliar a prevalência de fusão radicular e a incidência de canais em C nos dentes do primeiro molar superior (MFM) e do segundo molar superior (MSM) por meio da tomografia computadorizada de feixe cônico. Material e Métodos: Neste estudo, um total de 1233 MFMs e 1406 MSMs de 802 pacientes foram analisados. Primeiro, o número de dentes com raízes fundidas e o tipo de fusão radicular foram determinados. Posteriormente, a incidência e o número de canais em forma de C foram verificados de acordo com o tipo de fusão, localização, posição e nível de fusão do canal nos dentes com raízes fundidas. Seis tipos foram estabelecidos de acordo com as configurações em forma de C observadas. A presença de fusão radicular e do canal em C de acordo com sexo, idade e posição dentária foram avaliadas pelo teste do qui-quadrado. Valores com p <0,05 foram considerados significativos nos testes estatísticos. Resultados: A incidência de fusão nos dentes MFM e MSM foi de 6,16% e 22,40%, respectivamente. Apenas três MFMs (0,24%) e 3,77% dos MSMs tinham canais em forma de C. Enquanto a incidência de fusão foi maior em mulheres (p <0,05), a morfologia em forma de C não foi afetada pelo sexo (p> 0,05). Indivíduos com mais de 50 anos apresentaram menor incidência de canais em C (p <0,05). Conclusão: a morfologia do canal em forma de C foi mais comumente associada a tipos complexos de fusão radicular envolvendo três raízes; 16,83% dos HSH com raízes fundidas tinham canais em forma de C (AU).

Tratamiento de la fractura corono-radicular no complicada de la corona: caso clínico / Treatment of non-complicated crown-root fracture: a clinical case

El trauma dentoalveolar se define como aquella lesión de extensión e intensidad variable y de ori- gen accidental o intencional, causada por fuerzas que actúan sobre el órgano dentario y los tejidos que lo rodean. Se puede diagnosticar a simple vista o con ayuda de la radiografía, se debe tratar sin demora para preservar la vitalidad de la pulpa, sobre todo en casos de niños y adolescentes, to- mando en cuenta la formación radicular. El trau- ma dental es motivo de urgencia por el dolor que provocan en los pacientes, la prevalencia varia del 26 al 76% de las lesiones dentales en dentición permanente (AU)

Diagnóstico de reabsorção radicular: influência da resolução espacial de captura de imagens digitais periapicais / Root resorption diagnostic: influence of periapical digital image scanning

Introdução: a detecção da reabsorção da raiz dentária é realizada por meio de exames de imagens, pois frequentemente não apresenta sinal e sintoma clínicos. Dentre os exames de imagem disponíveis, o exame radiográfico periapical, é indicado para diagnóstico, prognóstico e acompanhamento da reabsorção radicular. Objetivo: o estudo tem como objetivo investigar a relação de diferentes resoluções espaciais com o diagnóstico de reabsorção radicular. Metodologia: foram realizados desgastes simulando reabsorção externa no terço apical e vestibular de 15 (quinze) incisivos inferiores, radiografados em crânio seco, antes e depois do desgaste. A técnica radiográfica foi realizada utilizando o sistema VistaScan (Durr Dental, Bietigheim-Bissingen, Germany), aparelho CS 2200 (Carestream Dental LLC, Atlanta-GA, USA) usando tempo de exposição de 0,15 segundos e escaneadas sob diferentes protocolos de resolução espacial, a saber, 20 pares de linhas por milímetro (pl/mm) e 40 pl/mm. Posteriormente dois avaliadores experientes fizeram análises das referidas imagens sem conhecimento prévio da resolução de escaneamento. Resultados: 75% das radiografias realizadas com 20 pl/mm foram classificadas como excelentes pelos avaliadores, contra 33% com 40 pl/mm, estatisticamente significativa. Discussão: ao avaliar a reabsorção radicular, obteve-se uma acurácia diagnóstica igual para os dois protocolos sem distinção, estatisticamente significativa, entre localização ou profundidade. Conclusão: tendo em vista que para os examinadores imagens com 20 pl/mm foram satisfatórias, com percentual de qualidade maior quando comparado a imagens obtidas com 40 pl/ mm, este estudo indica o emprego de imagens com 20 pl/mm para avaliação inicial de suspeita de reabsorções nas raízes dentárias.

Introduction: the detection of tooth root resorption is carried out by means of imaging tests, as it often does not present a clinical sign and symptom. Among the imaging tests available, the periapical radiographic examination is indicated for diagnosis, prognosis and monitoring of root resorption. Objective: the study aims to investigate the relationship of different spatial resolutions in the diagnosis of root resorption. Methods: Artificial external root resorptions were simulated using burs by drilling to the entire depth in different locations at the apical and buccal thirds of 15 (fifteen) lower incisors were worn, radiographed on a dry skull, before and after wear. The radiographic technique was performed using the VistaScan system (Durr Dental, Bietigheim-Bissingen, Germany), CS 2200 device (Carestream Dental LLC, Atlanta-GA, USA) using an exposure time of 0.15 seconds and scanned under different resolutions protocols, namely, 20 pairs of lines per millimeters (pl/mm) and 40 pl/mm. Subsequently, two experienced evaluators performed analyzes of these images without prior knowledge of the scanning resolution. Results: seventy-five percent of the radiographs taken at 20 pl/mm were rated as excellent by the evaluators, against 33% at 40 pl/mm, a statistically significant difference. Discussion: When assessing root resorption, a similar diagnostic accuracy was obtained for the two protocols without a statistically significant distinction between location or depth. Conclusions: Considering that for examiners images with 20 pl/mm were satisfactory, with a percentage of quality greater than 40 pl/mm, this study indicates the use of 20 pl/mm for initial evaluation of suspected root resorption.

Incidencia de fracturas dentales reportadas en la Ciudad de Chihuahua durante la pandemia por COVID-19 / Incidence of dental fractures reported in Chihuahua city during COVID-19 pandemic

Se presentan los casos de fracturas verticales sintomáticos que ameritaron la extracción de las órganos dentales afectados en un periodo de cinco meses durante la pandemia por COVID-19 en la ciudad de Chihuahua, México. Material y métodos: Se recolectaron 26 muestras para el estudio, proporcionadas por los cirujanos dentistas integrantes del Grupo de Egresados de la Facultad de Odontología de la Universidad Autónoma de Chihuahua. Resultados: Los resultados muestran diferencias a lo reportado previamente respecto al tipo de diente involucrado, sexo de los pacientes, restauraciones coronales y tratamientos endodóncicos previos. Conclusiones: Se puede suponer que las modificaciones en el estilo de vida de la población, sumadas a la angustia permanente, pueden ser factores que contribuyen a las fracturas dentales (AU)

There are cases of symptomatic vertical fractures that warranted the extraction of affected teeth are presented, over a period of five months during the COVID-19 pandemic in Chihuahua City, Mexico. Material and methods: 26 samples were collected for the study, provided by the dentist who were members of the Graduate Group of the Faculty of Dentistry of the Autonomous University of Chihuahua. Results: The results show differences from what was previously reported regarding the type of tooth involved, sex of patients, coronal restorations and previous endodontic treatments. Conclusions: It can be assumed that changes in the lifestyle of the population, added to permanent distress, may be factors to preserve dental fractures (AU)

Root anatomy and canal configuration of maxillary premolars: a cone-beam computed tomography study / Anatomía de la raíz y configuración del conducto de los premolares maxilares: estudio de tomografía computarizada de haz cónico

SUMMARY: The aim of the study was to determine the number and anatomical configuration of roots and root canals of maxillary first and second premolars using cone-beam computed tomography scans. n273 CBCT scans were evaluated, obtaining a sample of 592 maxillary premolars. Root number and root canal anatomy were categorized using Ahmed´s classification. Data was analyzed using Pearson's Chi-squared test. Two roots were present on 157 first premolars, one root in 132 premolars and three roots in 17. Second premolars presented one root in 266 samples and two roots in 20; no second premolars presented three roots. Eight different configurations were found; the most frequent was 2MP B1 P1 in first premolars (51,3 %) and 1MP1 (63.6 %) in second premolars. The most frequent morphology found in maxillary premolars in Chilean population was two and three roots. The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals, generally of low to medium complexity, similar to what is found in other ethnic groups.

RESUMEN: El objetivo de este estudio fue determinar el número y la configuración de raíces y canales radiculares de primeros y segundos premolares maxilares utilizado tomografía computacional de haz cónico. 273 TCHC fueron evaluados, obtenido una muestra de 592 premolares maxilares. El número de raíces y la anatomía de los canales radiculares fueron categorizados utilizando la clasificación de Ahmed. Los datos fueron analizados con la prueba Chi- Cuadrado de Pearson. Dos raíces fueron observadas en 157 primeros presentaron una raíz en 266 muestras y dos raíces en 20; no se encontraron tres raíces en segundos premolares. Ocho diferentes configuraciones fueron encontradas; siendo la más frecuente 2MP B1 P1 en primeros premolares (51,3 %) y 1MP1 (63,6 %) en segundos premolares. La morfología radicular más frecuentemente encontrada en premolares de población Chilena fue de dos y tres raíces. El análisis de la anatomía interna usando TCHC mostró una gran variabilidad de en la distribución de los canales radiculares. Generalmente de mediana y baja complejidad como los encontrados en otros grupos etnicos.

USP34 regulates tooth root morphogenesis by stabilizing NFIC / 国际口腔科学杂志·英文版

Tooth root morphogenesis involves two biological processes, root elongation and dentinogenesis, which are guaranteed by downgrowth of Hertwig's epithelial root sheath (HERS) and normal odontoblast differentiation. Ubiquitin-dependent protein degradation has been reported to precisely regulate various physiological processes, while its role in tooth development is still elusive. Here we show ubiquitin-specific protease 34 (USP34) plays a pivotal role in root formation. Deletion of Usp34 in dental mesenchymal cells leads to short root anomaly, characterized by truncated roots and thin root dentin. The USP34-deficient dental pulp cells (DPCs) exhibit decreased odontogenic differentiation with downregulation of nuclear factor I/C (NFIC). Overexpression of NFIC partially restores the impaired odontogenic potential of DPCs. These findings indicate that USP34-dependent deubiquitination is critical for root morphogenesis by stabilizing NFIC.

Clinical analysis on the root fracture of the maxillary first molar / 华西口腔医学杂志

OBJECTIVES@#This study aimed to investigate the common types and directions of root fractures of the maxillary first molar and the influence of root canal treatment on the prevalent sites of root fractures.@*METHODS@#A total of 274 maxillary first molars with root fractures diagnosed via cone beam computed tomography were included. The root fractures of nonendodontically and endodontically treated teeth were identified to be spontaneous and secondary root fractures, respectively. The sites, types, and directions of spontaneous and secondary root fractures were determined.@*RESULTS@#Among the spontaneous root fractures, the proportion of palatal root fractures (56.1%) was higher than those of mesial buccal root fractures (36.1%) and distal buccal root fractures (7.8%). Among the secondary root fractures, the proportion of mesial buccal root fractures (52.7%) was higher than those of palatal root fractures (36.5%) and distal buccal root fractures (10.8%). The distribution of predominant fracture sites was statistically significant (@*CONCLUSIONS@#This study provided an epidemiological basis for the clinical features of root fractures of the maxillary first molar. During the dia-gnosis and treatment of the maxillary first molar, the possibility of palatal root fractures should be considered. The occurrence of mesial buccal root fractures may be related to root canal treatment. Therefore, the risk of mesial buccal root fractures caused by iatrogenic factors should be minimized.

Expressions of cytokeratin 14 and proliferating cell nuclear antigen in the Hertwig's epithelial root sheath of a Vps4b knockout mouse / 华西口腔医学杂志

OBJECTIVES@#The effect of Vps4b gene mutation on the expressions of cytokeratin 14 (CK14) and proliferating cell nuclear antigen (PCNA) in the Hertwig's epithelial root sheath (HERS) is investigated.@*METHODS@#The bilateral mandibular tissues of mouse on postnatal days 5, 9, 11, 15, and 19 were removed. The mandibular first molar tissue sections were obtained after paraffin embedding. The CK14 and PCNA expressions in the epithelial root sheath of the normal mouse and Vps4b knockout mouse were compared through immunohistochemistry.@*RESULTS@#On postnatal day 5, the normal mouse began to form HERS and had a strong positive PCNA expression in the HERS cells; on postnatal day 9, the HERS structure was continuous, and PCNA was positive in the HERS cells; on postnatal day 11, a small portion of HERS began to break, and PCNA was weakly positive in the HERS cells; on postnatal day 15, HERS continued to fracture; PCNA was weakly and positively expressed in the HERS cells on the root surface; on postnatal day 19, the tooth root reached normal physiological length, and PCNA was positively expressed in the HERS cells of the terminal part. Similar to the normal mouse, the gene knockout mouse also formed a HERS structure on postnatal day 5. However, HERS began to break on postnatal day 9. On postnatal day 19, only a few fragments of HERS were found on the root surface, and the root development was immature. Moreover, the expression intensity of PCNA in the gene knockout mouse was decreased.@*CONCLUSIONS@#The Vps4b gene mutation may change the CK14 and PCNA expressions, leading to abnormal root development.

Effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption / 北京大学学报(医学版)

In recent years, developing new methods to accelerate orthodontic tooth movement (OTM) has attracted extensive attention in the field of orthodontic clinical and scientific research. It reduces orthodontic treatment time and risks. Over the past, various approaches have been done to accelerate orthodontic tooth movement. Several forms of corticotomy techniques have been effective in inducing rapid tooth movement. These techniques activate regional acceleratory phenomenon and create a favorable microenvironment for accelerating tooth movement. Root resorption is one of most common side effects of orthodontic treatment. It affects the long-term viability and health of teeth. However, the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption still remains unclear. Accelerating tooth movement may have two-side effects on root resorption. Through shortening the treatment period and removing the hyalinized tissues, the acceleration of orthodontic tooth movement could reduce root resorption. The increase of root resorption might be due to the local inflammation and function of cementoclasts/odontoclasts. In this paper, we reviewed the effects of different corticotomy techniques accelerating orthodontic tooth movement on root resorption. Corticotomy techniques deal with mucoperio-steal flaps and bone tissues differently and develop towards minimally invasive. Previous studies on root resorption use two-dimensional images, including apical films and panoramic tomography, to evaluate the degree of root resorption. In recent years, researches measure the volume of root resorption accurately using cone-beam computed tomography (CBCT) and micro-CT. Most studies suggest that the root resorption during acceleration of orthodontic tooth movement through corticotomy techniques is not statistically different from that of traditional orthodontic treatment. Some studies using micro-CT have shown that the root resorption in the groups of corticotomy techniques increases compared with the control group without surgery. Because of the short duration of these studies, the clinical significance is controversial on the overall impact of corticotomy techniques on orthodontic treatment. Accelerating orthodontic tooth movement is still at its emerging phase and need further research in the form of clinical trials to illustrate the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption.

Three-dimentional radiographic features of 67 maxillary radicular cysts / 北京大学学报(医学版)

OBJECTIVE@#To analyze the three-dimensional radiographic characteristics of maxillary radi-cular cysts using cone-beam computed tomography (CBCT) and spiral CT.@*METHODS@#Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 67 consecutive patients with maxillary radicular cysts were retrospectively acquired, and radiographic features, including size, shape, expansion, internal structure and relationship with the surrounding tissues, were analyzed. The lesions were divided into three types according to the involved tooth number, as follows: type Ⅰ (single tooth), the epicenter of the cyst was located at the apex of a nonvital tooth, without involvement of the neighbo-ring tooth; type Ⅱ (adjacent tooth involvement), the cyst was located at the apex of a nonvital tooth with involvement of the mesial and/or distal tooth root; and type Ⅲ (multi-teeth), the cyst involved the apexes of ≥4 teeth. Besides, these cysts were classified as another three types on sagittal views, as follows: centripetal, the root apex was oriented centripetally to the center of the cyst; palatal, the cyst was located mainly at the palatal side of the apex; and labial/buccal, the cyst was located mainly at the labial/buccal side of the apex.@*RESULTS@#Totally, 67 patients with maxillary radicular cysts were acquired, including 38 males and 29 females, and their ages ranged from 13 to 77 years. Among them, 46 lesions (68.7%) were located in the anterior maxilla and 65 (97.0%) were round or oval. Labial/buccal cortex expansion was present in 43 cases (64.2%) and palatal cortex expansion in 37 cases (55.2%). The nasal floor was invaded in 27 cases (40.3%), the maxillary sinus was invaginated in 26 cases (38.8%), and root resorption was present in 9 cases (13.4%). The average diameter of lesions was (20.89±8.11) mm mesio-distally and (16.70±5.88) mm bucco-palatally. In spite of the 4 residual cysts, the remaining 63 lesions included 14 type Ⅰ, 26 type Ⅱ and 23 type Ⅲ cysts according to the involved tooth number. Besides, the 63 lesions included 46 centripetal, 15 palatal and 2 buccal cysts on sagittal views.@*CONCLUSION@#The maxillary radicular cysts were frequently well-circumscribed round or oval radiolucency, with significantly different sizes. According to the involved tooth number, it can be divided into single tooth, adjacent tooth involvement and multi-teeth types. On sagittal views, the root-cyst relationship was centripetal in most cases, while a minority of cysts expanded palatally or buccally.