Avaliação tomográfica das dimensões verticais dos tecidos periodontais supracrestais em dentes anteriores da maxila / Tomographic evaluation of the vertical dimensions of periodontal supracrestal tissues in maxillary anterior teeth

O objetivo do presente estudo foi avaliar em tomografias computadorizadas as dimensões dos tecidos periodontais supracrestais (TPSC). Cem pacientes, 600 dentes anteriores da maxila (200 incisivos centrais, 200 incisivos laterais e 200 caninos), foram avaliados. A distância média da margem gengival até a crista óssea alveolar (COA) foi de 3.25mm (95% IC: 3.20-3.30), enquanto que da junção cemento-esmalte até a COA foi de 1.77mm (95% IC: 1.72-182mm). As medidas foram significativamente diferentes entre os grupos de dentes (ANOVA, p < 0.001). A tomografia, pode representar uma importante ferramenta para a avaliação das dimensões dos TPSC.

The aim of this study was to evaluate the dimensions of the supracrestal periodontal tissues (SPT) on tomographic scans. One hundred patients, 600 maxillary anterior teeth (200 central incisors, 200 lateral incisors and 200 canines), were evaluated. The average distance from the gingival margin to the alveolar bone crest (ABC) was 3.25mm (95% CI: 3.20-3.30), while the distance from the cemento-enamel junction to ABC was 1.77mm (95% CI: 1.72-182mm). The measurements were significantly different between the tooth groups (ANOVA, p < 0.001). When properly indicated, tomography can be an important tool for assessing the dimensions of TPSCs on a case-by-case basis.

Tomographic Evaluation of the Odontogenic Maxillary Myxoma. Case Report and Literature Review / Evaluación tomográfica del mixoma odontogénico en maxilar superior. Reporte de caso y revisión de la literatura

Odontogenic myxoma (OM) is a slow-growing, painless, aggressive and non-metastatic central jaw tumor of mesenchymal origin. Radiographically, it can vary from a unilocular radiolucent lesion to a multilocular lesion with well-defined or diffuse margins. The aim of this paper is to recognize the radiographic and tomographic characteristics of OM in a patient who attended the Dental Clinic of the Faculty of Dentistry of the Universidad Nacional Mayor de San Marcos in Lima-Peru. Case presentation: 86 year old male patient, who in the panoramic radiography indicated for his oral rehabilitation, a unilocular radiolucent image was found in the anterosuperior area with partially defined limits, corticalized edges and oval shape. In the volumetric tomography there was evidence of thinning and erosion of both bone tables, thinning of the floor of the nasal cavity. The radiolucent image seems to havean extension close to the alveolar ridge.In adition, there was an effacement of the cortices of the nasopalatine duct. The lesion was enucleated and an anatomopathological examination was performed. Diagnosis was odontogenic myxoma. The patient was evaluated at one year and six months with satisfactory results. The wide variety of radiographic characteristics of odontogenic myxoma leads us to think of a large number of differential diagnoses, being the histological evaluation together with the imaging analysis the ones that provide a definitive diagnosis. Although the anterosuperior area is the least common for its presentation, radiolucent images in this area should be considered as possible odontogenic myxomas, since this condition is more frequent in latín race.

El mixoma odontogénico (MO) es un tumor mandibular central de origen mesenquimal, de crecimiento lento, indoloro, agresivo y no metastásico. Radiográficamente, puede variar desde una lesión unilocular radiolúcida a una lesión multilocular con márgenes bien definidos o difusos. El objetivo de este trabajo es reconocer las características radiográficas y tomográficas del MO en un paciente que acudió a la Clínica Odontológica de la Facultad de Odontología de la Universidad Nacional Mayor de San Marcos en Lima-Perú. Presentación del caso: Paciente masculino de 86 años, en la radiografía panorámica indicada para rehabilitación oral, se encontró una imagen radiolúcida unilocular en la zona anterosuperior con límites parcialmente definidos, bordes corticalizados y forma ovalada. En la tomografía volumétrica se evidenció adelgazamiento y erosión de ambas tablas óseas, adelgazamiento del piso de la cavidad nasal, la imagen radiolúcida parece tener una extensión cercana a la cresta alveolar. Además, había un adelzamiento de las corticales del conducto nasopalatino. La lesión fue enucleada y se realizó un examen anatomopatológico. El diagnóstico fue mixoma odontogénico. La paciente fue evaluada al año y a los seis meses con resultados satisfactorios. La gran variedad de características radiográficas del mixoma odontogénico nos lleva a pensar en un gran número de diagnósticos diferenciales, siendo la evaluación histológica junto con el análisis de imagen los que proporcionan un diagnóstico definitivo. Aunque el área anterosuperior es la menos común para su presentación, las imágenes radiolúcidas en esta área deben ser consideradas como posibles mixomas odontogénicos, ya que esta condición es más frecuente en la raza latina.

Localización Morfológica del Foramen Mental con Tomografía Computarizada Cone-Beam en San Luis Potosí, México / Morphological Location of the Mental Foramen with Cone-Beam Computed Tomography in San Luis Potosí, Mexico

El foramen mental, una abertura en la parte inferior de la mandíbula, es la salida de un ramo del nervio alveolar inferior, proporcionando sensibilidad a la mandíbula y la piel del mentón. Su variabilidad anatómica es importante en procedimientos dentales y quirúrgicos. Nuestro estudio en San Luis Potosí, México, examinó la posición y características morfológicas del foramen mental en una muestra de tomografías computarizadas de la mandíbula. En mujeres, la zona entre el primer y segundo premolar fue la más común, mientras que en hombres, fue la misma zona pero con mayor prevalencia en el lado izquierdo. Se observaron diferencias en la dirección del foramen mental entre sexos y lados de la mandíbula, con la dirección posterior predominante en ambos sexos. Estos hallazgos concuerdan con estudios previos en diferentes poblaciones, aunque se identifican variaciones significativas en la prevalencia y ubicación específica del foramen. La comparación con otros estudios resalta la importancia de considerar factores étnicos y geográficos en la interpretación de los resultados. Las diferencias anatómicas observadas tienen implicaciones clínicas importantes para procedimientos dentales y quirúrgicos, subrayando la necesidad de enfoques adaptados a la población específica para mejorar la precisión y seguridad de las intervenciones en el área del mentón.

SUMMARY: The mental foramen, an opening at the bottom of the jaw, is the exit of the inferior alveolar nerve branch, providing sensation to the jawbone and skin of the chin. Its anatomical variability is important in dental and surgical procedures. Our study was carried out in San Luis Potosí, Mexico and examined the position and morphological characteristics of the mental foramen in a sample of lower jaw CT scans. In women, the area between the first and second premolar was the most common, while in men, it was the same area but with a greater prevalence on the left side. Differences in the direction of the mental foramen were observed between sexes and sides of the mandible, with the posterior direction predominating in both sexes. These findings are consistent with previous studies in different populations, although significant variations in the prevalence and specific location of the foramen are identified. The comparison with other studies highlights the importance of considering ethnic and geographic factors in the interpretation of results. The anatomical differences observed have important clinical implications for dental and surgical procedures, underscoring the need for approaches tailored to the specific population to improve precision and safety of interventions in the mental foramen area.

Unusually Pronounced and Expansive Mandibular Foramen. A Incidental Radiological Finding / Foramen Mandibular Inusualmente Pronunciado y Expansivo: Un Hallazgo Radiológico Incidental

SUMMARY: The mandibular foramen and its canal are one of the most important structures in the skull, as they solely supply the mandible through their associated nerves and vessels. Many anatomical variations have been reported in the literature until now, and this case report represents a clear-cut appearance of its shape in a panoramic radiograph, which is not mostly seen in normal panoramic radiographs. These factors are of utmost importance when it comes to performing various surgeries and preventing complications due to their varied anatomy, which will allow dentists to create a better treatment plan and provide better treatments without any complications.

El foramen mandibular y su canal son algunas de las estructuras más importantes del cráneo y cara, ya que a través de ellos la mandíbula es inervada por nervios e irrigada por vasos. Hasta ahora, en la literatura consultada, se han informado de numerosas variaciones anatómicas. En este trabajo reportamos la forma y trayecto del foramen y canal mandibular, obtenidos en una radiografía panorámica, que no es observada normalmente en este tipo de radiografía. Los factores anatómicos son de importancia a la hora de realizar las cirugías para prevenir complicaciones debido a su variada anatomía, permitiendo a los odontólogos crear un mejor plan de tratamiento sin ningún tipo de complicaciones.

Morphological Assessment of the Anterior Loop in the Region of Mental Foramen Using Cone Beam Computed Tomography / Evaluación Morfológica del Asa Anterior en la Región del Foramen Mentoniano Mediante Tomografía Computarizada de Haz Cónico

SUMMARY: Anterior loop in the mental foramen region is a critical region in the mandible. The non detection of anterior loop leads to inadvertent complications during the surgical procedures in this region. This study aimed to evaluate the morphological assessment of the mental foramen's anterior loop (AL) using (CBCT) cone-beam computed tomography. CBCT data was retrieved from January 2018 to December 2022 and screened for eligibility. Images were viewed using panoramic reconstructed views for initial screening. Further multiplanar reformatted view in axial, coronal and sagittal planes were examined. When anterior loop was detected, the path of inferior alveolar canal was traced and the anterior loop was analyzed. Statistical analysis was carried out on the data. Cross-tabulation was done to associate gender and age with the achieved findings (heights and diameters) using the Chi-square test. In this analysis 519 cases were included and examined for presence of anterior loop. 22 cases were included in the study, out of which 10(45.5%) males and 12(54.5%) females. The prevalence of AL is high among females. AL was found higher on the right side in 14 (68.2%) cases compared to the left side with 7 (31.8%) cases. The mean diameter of AL on the right side was 2.5 mm, and on the left side diameter was 1.96 mm. The prevalence of anterior loop in the region of mental foramen in Saudi Population was found to be 4.24%. Careful evaluation for the anterior loop can prevent hemorrhagic episodes during surgical intervention or implant procedures in the mandibular premolar region.

El asa anterior en la región del foramen mentoniano es una región crítica en la mandíbula. La no detección del asa anterior conduce a complicaciones inadvertidas durante los procedimientos quirúrgicos en esta región. Este estudio tuvo como objetivo evaluar la evaluación morfológica del asa anterior (AL) del foramen mental mediante tomografía computarizada de haz cónico (CBCT). Los datos CBCT se recuperaron desde enero de 2018 hasta diciembre de 2022 y se examinaron para determinar su elegibilidad. Las imágenes se visualizaron utilizando vistas panorámicas reconstruidas para la evaluación inicial. Se examinaron además, vistas reformateadas multiplanares en los planos axial, coronal y sagital. Cuando se detectó el asa anterior, se trazó el trayecto del canal mandibular y se analizó el asa anterior. Se realizó un análisis estadístico de los datos. Mediante la prueba de Chi-cuadrado se realizó una tabulación cruzada para asociar el sexo y la edad con los hallazgos obtenidos (alturas y diámetros). En este análisis se incluyeron y examinaron 519 casos para detectar la presencia de asa anterior. Se incluyeron en el estudio 22 casos, de los cuales 10 (45,5 %) eran hombres y 12 (54,5 %) mujeres. La prevalencia de AL es alta entre las mujeres. Se observó que AL fue mayor en el lado derecho en 14 (68,2 %) de los casos en comparación con el lado izquierdo con 7 (31,8 %) casos. El diámetro medio de AL en el lado derecho fue de 2,5 mm y en el lado izquierdo fue de 1,96 mm. La prevalencia del asa anterior en la región del foramen mental en la población saudí fue de 4,24 %. Una evaluación rigurosa del asa anterior puede prevenir episodios hemorrágicos durante una intervención quirúrgica o procedimientos de implante en la región de los premolares mandibulares.

Comparison of dental dimensions in models developed with digital procedures and plaster models / Comparación de dimensiones dentales en modelos desarrollados con procedimientos digitales y modelos en yeso

Aim: This study aimed to collect evidence on the validity and reliability of measurements obtained from digital impression techniques. Materials and Methods: This comparative study was conducted on 31 patients. Intraoral scanner was applied to all patients. For each patient, an alginate impression of the upper maxilla was taken and later the 3D digital model was extracted by dental cone-beam computed tomography (CBCT). For preparation of plaster models, alginate impressions were taken and immediately poured with dental stone. In the next stage, a comparison was performed among the intraoral scanner, CBCT, and plaster models in terms of tooth size, dental width, and intra-arch dimensions. Results: Measuring tooth size and intra-arch dimensions in digital images obtained from intraoral scanner and CBCT were in most cases lower than the results obtained in the plaster models but the differences between digital techniques and plaster models are not clinically noticeable. Conclusions: Digital systems including intraoral scanner and CBCT are acceptable for clinical use in terms of accuracy.

Objetivo: Este estudio tuvo como objetivo recopilar evidencia sobre la validez y confiabilidad de las mediciones obtenidas a partir de técnicas de impresión digital. Materiales y Métodos: Este estudio comparativo se realizó en 31 pacientes. A todos los pacientes se les aplicó escáner intraoral. Para cada paciente, se tomó una impresión de alginato del maxilar superior y posteriormente se extrajo el modelo digital 3D mediante Tomografía computarizada de haz cónico (CBCT) dental. Para la preparación de los modelos de yeso se tomaron impresiones de alginato y se vertieron inmediatamente con yeso dental. En la siguiente etapa, se realizó una comparación entre el escáner intraoral, CBCT y los modelos de yeso en términos de tamaño de diente, ancho dental y dimensiones intraarcada. Discusión: Se encontró que la apariencia microscópica de las células fusiformes era comparable en ambos grupos. Los resultados de la citometría de flujo demostraron expresiones comparables en ambos grupos, siendo las muestras positivas para CD90, CD73, CD105, HLA ABC y negativas para CD34, CD45 y HLA DR. Hubo variaciones en la expresión de los marcadores cuando se evaluaron los potenciales de diferenciación. Conclusión: Los sistemas digitales como el escáner intraoral y el CBCT son aceptables para uso clínico en términos de precisión.

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

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

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

Beneficios de la descompresión y enucleación en lesiones quísticas de gran tamaño en la mandíbula / Benefits of decompression and enuclation in large cystic lesions in the jaw / Benefícios da descompressão e enuclação nas grandes lesões císticas na mandíbula

Las lesiones quísticas ocurren en los maxilares, por la presencia de células remanentes del neuroectodermo embrionario. La descompresión es una técnica conservadora para disminuir la presión intraquística mediante drenaje constante, permitiendo el crecimiento de nuevo hueso centrípeto de las paredes óseas del quiste. Objetivo: determinar los beneficios de la descompresión y enucleación en lesiones quísticas mandibulares, tomando como base la metodología de un caso clínico. Descripción del caso: se diagnosticó una lesión quística mandibular en paciente masculino de 27 años, que acudió a consulta mostrando secreción purulenta en mucosa trígono retromolar de UD 37, inicialmente asintomática. Se utilizaron como materiales la tomográfica computarizada de haz cónico, artefacto de drenaje autocurado, hemiarcada izquierda elaborada con Metil Metacrilato y aparato a base de cilindro. Como resultados se reveló imagen hipodensa de bordes definidos localizada en el límite posterior de cuerpo mandibular, borde anterior y parte de la rama ascendente mandibular del lado izquierdo; extendida en sentido cefálico caudal desde la cresta alveolar y borde anterior de la rama hasta la cortical superior del conducto mandibular. Conclusión: Se confirmó diagnóstico de quiste periapical, quiste residual y ameloblastoma. Se realizó biopsia incisional de la lesión para estudio histopatológico y la descompresión con dispositivo personalizado a enucleación conminada con solución de Carnoy, resultando el tratamiento conservador efectivo complementado por la enucleación de una membrana quística más gruesa y menos friable.

Cystic lesions occur in the jaws due to the presence of remnant cells of the embryonic neuroectoderm. Decompression is a conservative technique to decrease intracystic pressure by constant drainage, allowing the growth of new centripetal bone from the bony walls of the cyst. Objective: to determine the benefits of decompression and enucleation in mandibular cystic lesions, based on the methodology of a clinical case. Case description: a cystic mandibular lesion was diagnosed in a 27 year old male patient, who came for consultation showing purulent secretion in the trigone retromolar mucosa of UD 37, initially asymptomatic. The materials used were cone beam computed tomography, self-curing drainage device, left hemiarch made with Methyl Methacrylate and cylinder based apparatus. The results revealed a hypodense image with defined borders located in the posterior limit of the mandibular body, anterior border and part of the ascending mandibular branch on the left side; extended in a caudal cephalic direction from the alveolar crest and anterior border of the branch to the superior cortical of the mandibular duct. Conclusion: Diagnosis of periapical cyst, residual cyst and ameloblastoma was confirmed. An incisional biopsy of the lesion was performed for histopathological study and decompression with a customized device to enucleation with Carnoy's solution, resulting in effective conservative treatment complemented by enucleation of a thicker and less friable cystic membrane.

As lesões císticas ocorrem nos maxilares, devido à presença de células remanescentes da neuroectoderme embrionária. A descompressão é uma técnica conservadora que visa reduzir a pressão intracística por meio de drenagem constante, permitindo o crescimento de novo osso centrípeto a partir das paredes ósseas do cisto. Objetivo: determinar os benefícios da descompressão e da enucleação em lesões císticas mandibulares, com base na metodologia de um caso clínico. Descrição do caso: foi diagnosticada uma lesão cística mandibular em um paciente do sexo masculino, 27 anos, que se apresentou para consulta apresentando secreção purulenta na mucosa do trígono retromolar do UD 37, inicialmente assintomática. Os materiais utilizados foram tomografia computadorizada de feixe cônico, dispositivo de drenagem autopolimerizável, hemiarco esquerdo confeccionado com metacrilato de metila e aparelho de base cilíndrica. Os resultados revelaram uma imagem hipodensa com limites definidos localizada no limite posterior do corpo mandibular, bordo anterior e parte do ramo mandibular ascendente do lado esquerdo; estendendo-se em direção cefálica caudal desde a crista alveolar e bordo anterior do ramo até ao córtex superior do ducto mandibular. Conclusão: Foi confirmado o diagnóstico de quisto periapical, quisto residual e ameloblastoma. Foi efectuada uma biopsia incisional da lesão para estudo histopatológico e descompressão com um dispositivo adaptado à enucleação cominutiva da solução de Carnoy, resultando num tratamento conservador eficaz complementado pela enucleação de uma membrana quística mais espessa e menos friável.

Mandibular Incisive Canal Morphometry: A Cone-Beam Computed Tomography Study in Jordan / Morfometría del Canal Incisivo Mandibular: Un Estudio de Tomografía Computarizada de Haz Cónico en Jordania

SUMMARY: Mandibular incisive canal (MIC) and related mental foramen (MF) and anterior loop (AL) morphometrics are important landmarks in medical and dental clinical applications. The main aim of this retrospective study to determine the morphometry of the mandibular incisive canal (MIC) in a Jordanian population and to propose a new shape-pattern classification of the MIC. In addition, MF and AL morphometrics were determined. Carestream 3D imaging software was used on 100 Cone-Beam Computed Tomography (CBCT) of a Jordanian population to determine the MF, AL and MIC morphometrics. The detection prevalence of the MIC was 96 %. The right and left MIC showed four distinct line patterns, proposed for the first time in this paper. The line-patterns were angular (L-line), straight (I-line), curved (V-line) and wavy (W-line), with a prevalence of 41 %, 19 %, 25.5 %, and 10.5 %, respectively. MF was detected in all mandibles with a round shape in 58 % of the images. The most common horizontal and vertical positions of the MF were H4 and H3 (73.5 %) and V3 and V2 (95 %), respectively. An accessory MF was detected in 14.5 % of the samples and was more prevalent in males and on the right side. AL was detected in 92.5 % of the samples and exhibited a pattern prevalence of 25.5 %, 40 % and 27 % for types I, II and III, respectively. Results revealed that asymmetry and gender differences between right and left MIC, MF, AL and AMF was seen in patient's mandibles. In conclusion, this is the first study to propose and show that Mandibular incisive canal exhibits four potential line patterns (L, I, V and W lines patterns). Gender and ethnic variations of the mandibular canal landmarks morphometrics of both right and left hemi-mandible are important to be acknowledged in learning anatomy and when planning or performing dental and medical procedures.

Las relaciones de la morfometría del canal incisivo mandibular (MCI), del foramen mentoniano (FM) y del asa anterior (AA) son hitos importantes en las aplicaciones clínicas médicas y dentales. El objetivo principal de este estudio retrospectivo fue determinar la morfometría del MCI en una población jordana y proponer una nueva clasificación de patrón de forma del MCI. Además, se determinaron la morfometría de FM y AA. Se utilizó el software de imágenes 3D Carestream en 100 tomografías computarizadas de haz cónico (CBCT) de una población jordana para determinar la morfometría de FM, MCI y AA. La prevalencia de detección de MCI fue del 96 %. El MCI derecho e izquierdo mostraron cuatro patrones de líneas distintas, propuestas por primera vez en este artículo. Los patrones de líneas fueron angulares (línea L), rectos (línea I), curvos (línea V) y ondulados (línea W), con una prevalencia del 41 %, 19 %, 25,5 % y 10,5 % respectivamente. Se detectó el FM en todas las mandíbulas y con forma redonda en el 58 % de las imágenes. Las posiciones horizontal y vertical más comunes del FM fueron H4 y H3 (73,5 %) y V3 y V2 (95 %), respectivamente. Se detectó FM accesorio en el 14,5 % de las muestras y fue más prevalente en el sexo masculino y en el lado derecho. AA se detectó en el 92,5 % de las muestras y exhibió un patrón de prevalencia del 25,5 %, 40 % y 27 % para los tipos I, II y III, respectivamente. Los resultados revelaron asimetría y diferencias en el sexo entre MCI, FM, AA derecha e izquierda en las mandíbulas de los pacientes. En conclusión, este es el primer estudio que propone y muestra que el canal incisivo mandibular exhibe cuatro patrones de líneas potenciales (patrones de líneas L, I, V y W). Es importante reconocer las variaciones étnicas y de sexo de la morfometría de los puntos de referencia del canal mandibular de la hemimandíbula derecha e izquierda al estudiar y aprender anatomía y al planificar o realizar procedimientos médicos y dentales.

Reabsorción radicular en premolares, posterior a ortodoncia de autoligado, utilizando tomografía computarizada / Root resorption in premolars after self-ligating orthodontic treatment, using computed tomography

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.

Descripción de la Morfología del Sistema de Canales Radiculares en Premolares Maxilares Mediante Tomografía Computarizada Cone Beam en una Población Chilena

El tratamiento endodóntico requiere detallados conocimientos sobre la morfología radicular. En premolares maxilares, se ha reportado variabilidad en el número de raíces y morfología del sistema de canales radiculares (SCR). La causa más frecuente de fracaso endodóntico son los conductos no tratados. Por lo tanto, una mejor compresión de la morfología del SCR y sus variaciones es crucial para el tratamiento endodóntico. El objetivo de esta investigación fue describir la frecuencia del número de raíces y morfología del SCR en premolares maxilares, mediante exámenes de tomografía computarizada Cone Beam (CBCT) en una población chilena. Se realizó un estudio observacional descriptivo de corte transversal donde se observó la morfología del sistema de canales radiculares de primeros y segundos premolares maxilares a través de exámenes CBCT, agrupándolos de acuerdo con la Clasificación de Vertucci. Se observaron 228 exámenes CBCT, donde se incluyeron 268 primeros premolares superiores y 233 segundos premolares maxilares. Se determinó que en primeros premolares maxilares un 56,3 % presentó una raíz, un 43,3 %, siendo más frecuente una morfología del SCR tipo IV. En los segundos premolares maxilares, se determinó la presencia de una raíz en el 95,7 % de los casos, siendo más frecuente una morfología del SCR tipo I. Estos resultados pueden ser de interés para endodoncistas, ya que conocer la morfología del SCR de premolares maxilares permite mejorar la planificación de la terapia endodóntica realizada en estos dientes.

Endodontic treatment requires detailed knowledge of root morphology. In maxillary premolars, variability in root number and root canal system (RCS) morphology has been reported. The most frequent cause of endodontic failure is non treated canals. Therefore, a better understanding of RCS morphology and its variations is crucial for endodontic treatment. The aim of this research was to describe the frequency of root number and SCR morphology in maxillary premolars, by means of Cone Beam Computed Tomography (CBCT) examinations in a Chilean population. A cross-sectional descriptive observational study was carried out in which the morphology of the root canal system of maxillary first and second premolars was observed through CBCT examinations, grouping them according to the Vertucci Classification. A total of 228 CBCT examinations were observed, which included 268 upper first premolars and 233 maxillary second premolars. It was determined that in maxillary first premolars 56.3 % presented one root, 43.3 %, being more frequent a SCR type IV morphology. In maxillary second premolars, the presence of one root was determined in 95.7 % of the cases, being more frequent a SCR type I morphology. These results may be of interest to endodontists, since knowing the morphology of the RCS of maxillary premolars allows improving the planning of endodontic therapy performed on these teeth.

Evaluación de Protocolos de Autotrasplante Dental Guiado y sus Tasas de Supervivencia y Éxito. Una Revisión Sistemática

Actualmente los factores que influyen en la supervivencia de los dientes trasplantados han podido ser controlados con el uso de la tecnología. El autotrasplante dental guiado ha logrado más predictibilidad y eficiencia, además, h a reducido los tiempos de transferencia desde la extracción hasta el trasplante. El objetivo de esta revisión es describir los protocolos de autotrasplante dental guiado, sus tasas de supervivencia y éxito publicados en la literatura actual. Esta revisió n fue realizada siguiendo la pauta PRISMA. La búsqueda se realizó en MEDLINE, Google Académico, ScienceDirect y SciELO, con los términos "autotransplant", "autotransplantation", "autotransplanting", "dental", "tooth", "teeth", "guided", "guide" con filtro de publicación de 10 años. Se realizó evaluación de riesgo de sesgo mediante pautas Joanna Briggs Institute (JBI) a los estudios, incluyendo en esta revisión sólo con riesgo medio y bajo. Los datos de cada artículo se tabularon en una tabla realizada en el procesador de texto en línea "Google Docs". Diez estudios cumplieron los criterios mencionados y fueron incluidos. Fueron evaluados un total de 37 pacientes entre 9 a 64 años. Los dientes donantes más frecuentes fueron premolares y terceros molares. En la mayoría de los casos los pacientes se encontraban sin antecedentes mórbidos de relevancia. El éxito fue evaluado mediante diversos criterios clínicos y radiográficos. Por otro lado, la supervivencia fue evaluada durante los seguimientos respecto a la permanencia del diente en boca. Este tipo de tratamiento no es muy conocido y los estudios incluidos fueron escasos, por otro lado, estos son de bajo nivel de evidencia (reportes de casos y serie de casos). Los protocolos evaluados difieren en algunas características, sin embargo, todos logran altas tasas de supervivencia y éxito. Igualmente, se presentan algunos fracasos, dónde los dientes debieron ser extraídos por movilidad e inflamación.

Currently, the factors that influence the survival of transplanted teeth have been controlled with the use of technology. Guided dental autotransplantation has achieved greater predictability and efficiency, and has also reduced transfer times from extraction to transplantation. The aim of this review is to describe the protocols of guided dental autotransplantation, their survival and success rates published in the current literature. This review was performed following the PRISMA guideline. The search was carried out in MEDLINE, Google Scholar, ScienceDirect and SciELO, with the terms "autotransplant", "autotransplantation", "autotransplanting", "autotransplanting", "dental", "tooth", "teeth", "guided", "guide" with a 10-year publication filter. Studies were assessed for risk of bias using Joanna Briggs Institute (JBI) guidelines, including only medium and low risk studies in this review. The data for each article were tabulated in a table created in the online word processor "Google Docs". Ten studies met the selection criteria and were included. A total of 37 patients between 9 and 64 years of age were evaluated. The most frequent donor teeth were premolars and third molars. In most cases the patients had no relevant morbid history. Success was evaluated by means of various clinical and radiographic criteria. On the other hand, survival was evaluated during the follow-ups with respect to the permanence of the tooth in the mouth. This type of treatment is not very well known, and the studies included were scarce; on the other hand, they are of a low level of evidence (case reports and case series). The evaluated protocols differ in some characteristics, however, all of them achieve high survival and success rates. There are also some failures, where teeth had to be extracted due to mobility and inflammation.

Relationship between the Volume of the Upper Airways and the Mandibular Angle Analyzed in Computed Tomography Scans / Relação do Volume das Vias Aéreas Superiores com o Ângulo Mandibular Analisadas em Tomografias Computadorizadas

Several variables can influence the treatment and outcome of orthognathic surgery, one of which is the angle of the mandibular ramus. The objective of this study is to analyze the upper airways (UA) of patients prior to orthognathic surgery, using cone-beam computed tomography (CBCT) and to correlate their volume with the angle of the mandibular ramus. DICOM (Digital Image Communication in Medicine) images of a radiology clinic were used, with a survey of 124 full face CBCT scans, from 2015 to 2018, and the measurement of the total volume in mm³ through software. To obtain the values of the angle of the mandibular ramus, images obtained from medical reports were used, through morphological evaluation. The values were tabulated and subsequently statistical analysis was performed using the ANOVA test to assess the differences between the mean airway volumes (mm³) according to gender, age and mandibular ramus angle. However, the angle of the ramus did not influence the volume of the UA, but a greater average of UA volume was observed in male individuals and in individuals over 34 years of age. There is no evidence that it is possible to measure or predict the volume of the UA by evaluating the angle of the mandibular ramus. (AU)

Diversas as variáveis podem influenciar no tratamento e resultado de uma cirurgia ortognática, uma delas é o ângulo do ramo mandibular. O objetivo deste trabalho é analisar as vias aéreas superiores (VAS) de pacientes previamente à cirurgia ortognática, por meio de tomografia computadorizada de feixe cônico (TCFC) e correlacionar o seu volume com o ângulo do ramo mandibular. Foram utilizadas imagens DICOM (Comunicação de Imagens Digitais em Medicina) de uma clínica radiológica, com o levantamento de 124 exames de TCFC de face total, do ano de 2015 até 2018 e feita a mensuração do volume total em mm³ através de um software. Para a obtenção dos valores do ângulo do ramo mandibular foram utilizadas imagens obtidas através dos laudos médicos, mediante avaliação morfológica. Os valores foram tabulados e posteriormente feita a análise estatística com o teste ANOVA para avaliar as diferenças entre as médias de volume das vias aéreas (mm³) de acordo com o gênero, a idade e o ângulo do ramo mandibular. Contudo, o ângulo do ramo não influenciou no volume das VAS, mas uma maior média de volume de VAS foi observada nos indivíduos do gênero masculino e nos indivíduos acima de 34 anos. Não há evidências de que se é possível mensurar ou ter previsibilidade do volume de VAS, avaliando o ângulo do ramo mandibular. (AU)

Apical periodontitis in endodontically-treated teeth: association between missed canals and quality of endodontic treatment in a Colombian sub-population. A cross-sectional study / Periodontite apical em dentes tratados endodonticamente: associagao entre canais nao localizados e qualidade do tratamento endodontico em uma populagao colombiana: Um estudo transversal

ABSTRACT A high prevalence of post-treatment apical periodontitis associated to variables such as endodontic treatment quality and missed canals has been reported. Aim The aim of this study was to evaluate the quality of endodontic treatment and the frequency of missed canals associated with teeth with apical periodontitis (AP) through CBCT in a Colombian sub-population. Material and Method This was a crosssectional study assessing 318 cone beam computed tomography (CBCT) scans of endodontically treated teeth from Colombian individuals. The scans were taken using J Morita X550 (J Morita Corporation, Osaka, Japan), with voxel size 0.125 to 0.20 mm. All endodontically treated teeth were assessed for quality of treatment, presence of missed canals and AP. All samples were analyzed by two endodontics specialists and an radiology specialist. Chi-square or Fisher's test and odds ratio were calculated to identify the association and risk relationship between the presence of AP and the study variables. Results Missed canals were found in 18.61% (86/462), and 95.3% were associated with AP. The frequency of AP was 62.34% (288/462) for all the evaluated teeth. AP was found in 27.43 % (79/288) of the teeth with adequate endodontic treatment, in contrast to 72.57% (209/288) of the teeth with inadequate treatment (P<0.01). The frequency of missed canals was highest in maxillary molars, with 55.23% (58/105), with 96.55% presenting AP. The second mesiobuccal canal was the most frequently missed canal, 88.52% (54/61), with AP in 90.74% (49/54) of the cases. Conclusion There was a high frequency of teeth with missed canals and PA. More than half of the teeth with missed canals were maxillary molars, with MB2 being the most common canal, commonly presenting apical periodontitis.

RESUMO Uma alta prevalência de periodontite apical pós-tratamento associada a variáveis como qualidade do tratamento endodôntico e fracasso do tratamento é relatada na literatura. O objetivo deste estudo foi avaliar a qualidade do tratamento endodôntico e a frequência e fracasso do tratamento associados a dentes com periodontite apical (PA) por meio de tomografia computadorizada de feixe cônico (TCFC) em uma subpopulação colombiana. Material e Método Este foi um estudo transversal que avaliou 318 tomografias computadorizadas de dentes tratados endodonticamente de indivíduos colombianos. Os exames foram realizados utilizando o tomógrafo J Morita X550, com tamanho de voxel de 0,125 a 0,20 mm. Todos os dentes tratados endodonticamente foram avaliados quanto à qualidade do tratamento, presença de canais não localizados e AP. Todas as amostras foram avaliadas por dois especialistas em endodontia e um especialista em radiologia. Foram calculados o teste qui-quadrado ou de Fisher e a razão de chances para identificar associação e relação de risco entre a presença de PA e as variáveis do estudo. Resultados Foram encontrados canais não localizados em 18,61% (86/462) e 95,3% estavam associados à PA. A frequência de AP foi de 62,34% (288/462) para todos os dentes avaliados. AP foi encontrada em 27,43% (79/288) dos dentes com tratamento endodôntico adequado, em contraste com 72,57% (209/288) dos dentes com tratamento inadequado (P<0,01). A frequência de canais não localizados foi maior nos molares superiores, com 55,23% (58/105), sendo que 96,55% apresentavam PA. O canal mésio-palatino (MB2) apresentou maior frequência de canal não localizado (88,52% - 54/61), com PA em 90,74% (49/54) dos casos. Conclusão Houve alta frequência de dentes com canais não localizados e com PA. Mais da metade dos dentes com canais não localizados eram molares superiores, sendo o MB2 é o canal com a maior frequência, comumente apresentando periodontite apical.

CBCT analysis of the relative position between maxillary central incisors and alveolar bone in Southern Chinese adults / 口腔疾病防治

Objective@#Exploring the position and bone wall thickness characteristics of the maxillary central incisors in Southern Chinese adults to provide a clinical reference for the design of immediate maxillary central incisor implantation surgery.@*Methods@#The hospital ethics committee approved the study, and the patients provided informed consent. CBCT images of 990 adult patients (aged 20-79 years) from the Stomatology Hospital (January 2018 to December 2021) were categorized based on the dental arch form and age-sex groups. Sagittal CBCT images of the maxillary central incisors were used to measure the labial and palatal bone thickness wall at 4 mm the CEJ to apical, the middle of the root, and the angle between the tooth long axis and the long axis of the alveolar process, to compare the thickness of the labial and palatal bone walls in samples of male and female patients, and to explore the relationship between the angle between the tooth long axis and the alveolar process long axis in samples of male and female patients in different age groups (20-39 years; 40-59 years; 60-79 years).@*Results@#Significant differences were found in the labiopalatine side of the alveolar bone of the maxillary incisor root position. A total of 95.8% (948/990) of the maxillary incisors were positioned more buccally, 4.1% (41/990) were positioned more midway, and 0.1% (1/990) were positioned more palatally. The thicknesses of the bone wall at the CEJ of 4 mm below the palatal side, the middle of the root, and at the apex were greater (1.82 ± 0.56 mm, 3.20 ± 1.10 mm, and 7.70 ± 2.00 mm, respectively) than those at the labial side (1.21 ± 0.32 mm, 0.89 ± 0.35 mm, and 1.86 ± 0.82 mm, respectively), with statistical significance (P<0.05). Male bone wall thickness was generally greater than female bone wall thickness (P<0.05). The angle between the long axis of male teeth and the alveolar bone was 14.77° ± 5.66°, while that of female teeth was 12.80° ± 5.70°, with a statistically significant difference (P<0.05). The angle between the long axis of teeth and the alveolar bone in the 40-59-year-old group and the 60-79-year-old group was greater than that in the 20-39-year-old group, and the difference was statistically significant (P<0.05).@*Conclusion@#A total of 95.8% of adults in South China have maxillary central incisors with root deviation toward the labial bone cortex. The thickness of the labial bone wall is much thinner than that of the labial bone wall, which is the middle of the thickness of the root. In Southern Chinese adults, the angle between the upper central incisor and the long axis of the alveolar bone in males is greater than that in females, and the degree of the angle increases with age. It is recommended to pay attention to the thickness of the bone wall around the root and the angle between the teeth before immediate implantation surgery to choose a reasonable implantation plan.

Evaluation of condylar position in patients with malocclusion and changes in condylar position before and after orthodontic treatment using cone beam computed tomography / 口腔疾病防治

@#The functional health and stability of the oral and maxillofacial system is one of the basic goals of orthodontic treatment. Currently, it is believed that, in general, the condyle is located in the center of the joint fossa when the mandible is in an intercuspal position (ICP) in healthy normal people. At this time, the function of the temporomandibular joint (TMJ) is stable. Due to orthodontic tooth movement and subsequent occlusal changes, patients with malocclusion may experience related remodeling of the temporomandibular joint, especially changes in the position of the condyle. The position of the mandibular condyle is traditionally evaluated using a condylar position indicator. However, this method lacks consistency in obtaining condylar position changes. In recent years, in the clinical application of orthodontic treatment, cone beam computed tomography (CBCT) has become the first choice for examination. CBCT can accurately measure the interarticular space and determine changes in condylar position. This article reviews the CBCT assessment of condylar position and related research on condylar position changes in patients with malocclusion before and after orthodontic treatment. The literature review results indicate that there are differences in the condylar position of patients with different malocclusions, and the condylar position may also change before and after orthodontic treatment. With a lower radiation dose, CBCT has higher accuracy in evaluating the condylar position in patients with malocclusion who undergo orthodontic treatment, thus promoting further study of the mechanism of condylar position changes in patients with malocclusion in the future and providing more accurate and personalized guidance for patient treatment.

Three-dimensional radiographic features of calcifying odontogenic cyst and calcifying epithelial odontogenic tumor / 北京大学学报(医学版)

Objective:To analyze the three-dimensional radiographic characteristics of calcifying odon-togenic cyst and calcifying epithelial odontogenic tumor using spiral computed tomography(CT)and cone-beam computed tomography(CBCT).Methods:Clinical records,histopathological reports,and CBCT or non-enhanced spiral CT images of 19 consecutive patients with calcifying odontogenic cyst(COC)and 16 consecutive patients with calcifying epithelial odontogenic tumor(CEOT)were retrospec-tively acquired,and radiographic features,including location,size,expansion,internal structure and calcification,were analyzed.Results:Among the 19 COC cases(12 males and 7 females,with an average age of 27 years),89.5％(17/19)of the lesions originated from the anterior and premolar areas,100.0％of them exhibited cortex expansion,and 78.9％had discontinued cortex.Among the 16 CEOT cases(3 males and 13 females,with an average age of 36 years),81.3％(13/16)of the lesions were in the premolar and molar areas,56.3％of them exhibited cortex expansion,and 96.8％had discontinued cortex.According to the distribution of internal calcifications,these lesions were divided in-to:Ⅰ(non-calcification type):absence of calcification;Ⅱ(eccentric marginal type):multiple calcifi-cations scattered along one side of the lesion;Ⅲ(diffused type):numerous calcifications diffusely dis-tributed into the lesion;Ⅳ(plaque type):with a ≥ 5 mm calcified patch;V(peri-coronal type):multiple calcifications clustered around impacted teeth.Calcifications were present in 73.7％of COC le-sions,including 9 type Ⅱ,3 type Ⅲ and 2 type Ⅳ lesions,and 42.8％of CEOT lesions had calcifica-tion images,including 2 type Ⅲ and 5 type V lesions.Six COC lesions had odontoma-like images.Moreover,8 of 9 type Ⅰ CEOTs were histologically Langerhans cell-rich subtype,which had a smaller size(with an average mesiodistal diameter of 17.8 mm)and were not associated with impacted teeth.Conclusion:COC lesions tended to originate from the anterior part of the jaw and exhibit cortex expan-sion,and were sometimes associated with odontoma.CEOT commonly occurred in the posterior jaw and had discontinued cortex.Two lesions had significantly different calcification map.Over 70％of COC le-sions had calcification images,which were mostly scattered along one side of the cysts,far from the im-pacted teeth.Approximately 60％of CEOT lesions exhibited smaller size and non-calcification,and the remaining CEOT cases often had calcification images clustered around the impacted teeth.

Image quality of CBCT under different exposure parameters / 实用口腔医学杂志

Objective:To investigate the imaging quality of CBCT under different exposure parameters and the relationship between subjective and objective evaluation.Methods:CBCT scanners of 6 different suppliers[3D Accuitomo(Morita),i-mCAT(Kavo),5G(NewTom),Smart3D(Beijing Langshi),DCT Pro(Vatech),Vgi(NewTom)]were used to scan the spatial resolution models and head simulators under typical exposure conditions(different device with different tube voltage and current for exposure).The visibility of SedentexCT IQ phantom and anatomical structures generated by different CBCT scanners were compared.For objective evaluation,7 professional evaluators scored CBCT imaging qualities.For subjective evaluation,the resolution(LP/mm)of the images were com-pared among the devices.Results:No significant difference was found by 7 evaluators either intra or inter of the teams.By objective e-valuation,the score of NewTom 5G was 2,that of i-CAT was 5 and that of the others was 4.By subjective evaluation,the LP/mm of i-CAT was 1.8,that of Smart3D was 2.0 and that of the others was 1.0-1.7.The subjective evaluation of image quality obtained un-der different tube voltages and tube currents were significantly different.Conclusion:The subjective and objective evaluations of image quality are approximately consistent.The difference of the subjective image quality may be produced by the different tube voltage and current for exposure.

Consistency of gingival thickness measurement based on cone-beam CT imaging and cone-beam CT superimposed intraoral scan imaging / 中国组织工程研究

BACKGROUND:Gingival thickness is an important indicator to determine gingival phenotype.The correct evaluation of gingival phenotype is helpful for the smooth going of periodontal surgery,implant implantation and orthodontic treatment.The search for a comfortable,accurate and convenient method of measuring gingival thickness has always been a research hotspot in this field. OBJECTIVE:To analyze the gingival thickness in different dental positions and to study the consistency of cone-beam computed tomography(CBCT)image and digital intraoral scanners and cone-beam computed tomography(DIS-CBCT)superimposition image for measuring gingival thickness and determining whether the gingiva is thick or thin. METHODS:Twenty volunteers(10 males and 10 females)with complete maxillary dentition were recruited.The thickness of the gingiva 2 mm below the buccal gingival margin of 160 teeth was measured by CBCT image and DIS-CBCT digital superimposition image.Gingival thickness was used to determine whether the gingiva was thick or thin.Paired t-test was used to analyze the differences in gingival thickness measured by the two methods.Pearson correlation analysis was used to evaluate the correlation between the gingival thickness results of the two methods.The intraclass correlation coefficient(ICC)and Bland-AItman chart were used to analyze the repeatability and consistency in measuring gingival thickness using the two methods.Kappa value was used to analyze the consistency in determining whether the gingiva was thick or thin using the two methods. RESULTS AND CONCLUSION:The gingival thickness measured by CBCT image and DIS-CBCT digital superimposition image was(1.47±0.39)and(1.42±0.36)mm,respectively(t=5.673,P＜0.05).Pearson correlation analysis showed that the gingival thickness measured by the two methods was positively correlated(r=0.968,P＜0.001).In the CBCT group,the values of intraobserver and interobserver ICC were 0.980-0.982 and 0.984,respectively;in the DIS-CBCT group,the values of intraobserver and interobserver ICC were 0.941-0.984 and 0.964,respectively(P＜0.001).The intergroup ICC value of gingival thickness measured by the two methods was 0.967(P＜0.001).Bland-AItman analysis showed that 4.37%(7/160)of the points measured by both methods for gingival thickness was outside the 95%limits of agreement.There were 71 cases of thick-gingiva and 89 cases of thin-gingiva measured by CBCT imaging,and 59 cases of thick-gingiva and 101 cases of thin-gingiva measured by DIS-CBCT digital superimposition image.The Kappa value of the two groups was 0.845(P＜0.001).These findings indicate that there is a significant difference in the thickness measurement of the gingiva 2 mm below the gingival margin between the CBCT group and the DIS-CBCT group,but the correlation is very strong.The repeatability and consistency of gingival thickness measurement are both high,and there is a good consistency between the two methods when used to determine whether the gingiva is thick or thin.

Research on the improvement of CBCT image quality based on region-discriminative generative adversarial networks in radiotherapy for cervical cancer / 中国医学装备

Objective:To propose a model that could improve image quality of cone-beam computed tomography(CBCT),which based on region-discriminative generative adversarial networks(GAN),in radiotherapy for cervical cancer,so as to meet the requirements of self-adaptive radiotherapy for image quality.Methods:We employed a region-discriminative strategy and a generative adversarial networks idea to construct a model of improving CBCT image quality that could focus on local details of the images of radiotherapy for cervical cancer,which discriminator could improve the quality of generating local details of images.This model of image quality was applied to CBCT images of radiotherapy for cervical cancer.And then,the effects of processing image were evaluated through quantitative indicators and visualization.Results:Both texture clarity and contrast were significantly enhanced after CBCT image quality was improved.The signal to noise ratio of peak value of images was increased by 47.2%,and the indicator of similarity of structure was enhanced to>0.838.Compared with other model,both visualization and indicators can appear better efficiency of model.Compared with Unet network and CycleGAN network,the similarities of structure were respectively increased by 11.88% and 19.54%,and the signal to noise ratios were respectively increased by 19.75% and 25.99%.Conclusion:The GAN bases on region-discrimination can significantly improve the quality of generating integral and detailed CBCT image of radiotherapy for cervical cancer,which can provide new technical pathway for image quality of CBCT with low dose,and can play an important role for improving safety and effectiveness of radiotherapy.It has importantly clinical value for formulating and executing radiotherapy plan.