Ankylosis of Permanent First Molar: Diagnosis by Cone Beam Computed Tomography / Anquilosis del Primer Molar Permanente: Diagnóstico por Tomografía Computarizada con Haz Cónico

ABSTRACT: Ankylosis is an anomaly of tooth eruption characterized by the fusion of cementum and alveolar bone, and may affect from small regions to the entire root surface. Clinical assessment combined with imaging exams can aid diagnosis. Radiographic testing enables assessing only proximal regions of possibly affected roots. Whereas cone beam computed tomography (CBCT) allows a three-dimensional assessment of axial, coronal, and sagittal planes of all dental extension, eliminating thus overlapping images and helping to confirm the correct diagnosis. The present study contains a case report of a male patient with ankylosis in tooth 16 diagnosed by CBCT, aiming at providing information for dentists about this anomaly, its characteristics and situations in which CBCT should be indicated.

RESUMEN: La anquilosis es una anomalía de la erupción del diente caracterizada por la fusión de cemento y hueso alveolar, y puede afectar desde pequeñas regiones hasta toda la superficie de la raíz. La evaluación clínica combinada con los exámenes de imagen puede ayudar a diagnosticar esta anomalía. Las pruebas radiográficas permiten evaluar sólo las regiones proximales de las raíces posiblemente afectadas. La tomografía computarizada de haz de cono (CBCT) permite una evaluación tridimensional de los planos axial, coronal y sagital de toda la extensión dental, eliminando así las imágenes superpuestas y ayudando a confirmar el diagnóstico correcto. En el presente estudio se presenta un reporte de caso de un paciente con anquilosis en el diente 16 diagnosticado por CBCT, con el objetivo de proporcionar información para los dentistas sobre esta anomalía, sus características y situaciones en las que debe indicarse la CBCT.

Monostotic fibrous dysplasia: a case report with cone-beam computed tomography findings / Displasia fibrosa monostótica: relato de caso por meio de achados de tomografia computadorizada de feixe cônico

ABSTRACT Fibrous dysplasia is a benign fibrous-osseous lesion in which normal bone is replaced by fibrous connective tissue and immature bone, affecting only one (monostotic) or several bones (polyostotic) and mainly occurring in children and young adults. When present in facial bones, the maxilla is more frequently involved than the mandible, which can cause facial asymmetry in addition to dental complications. In the image exams, the main characteristic of fibrous dysplasia is its unpolished glass appearance. Computed tomography is the ideal method for evaluating this lesion and its relationship with adjacent structures. The use of conventional radiography, due to the overlapping of anatomical structures, makes it difficult to delineate the extension of the lesion. The present study is aimed at guiding dentist-surgeons on the main imaging characteristics of fibrous dysplasia by describing a case of a female 10-year-old patient presenting with this lesion in the maxilla.

RESUMO A displasia fibrosa é uma lesão fibro-óssea benigna em que o osso normal é substituído por tecido conjuntivo fibroso e osso imaturo, podendo afetar um único osso (monostótica) ou vários ossos (poliostótica), ocorrendo principalmente em crianças e adultos jovens. Quando presente nos ossos faciais, a maxila é envolvida com mais frequência que a mandíbula, podendo causar assimetria facial, além de complicações odontológicas. Nos exames por imagem a característica principal da displasia fibrosa é a aparência de vidro despolido. A tomografia computadorizada é o método ideal para avaliação dessa lesão e relação com estruturas adjacentes. A radiografia convencional, devido a sobreposição de estruturas anatômicas, torna difícil a delimitação da extensão da lesão. O presente estudo teve como objetivo apresentar o relato de caso de um paciente do sexo feminino, 10 anos de idade, com presença de displasia fibrosa na maxila, objetivando orientar os cirurgiões-dentistas com relação às principais características imaginológicas dessa lesão.

Cone beam computed tomography in the diagnosis of dens invaginatus: case report / Tomografía computarizada de haz cónico en el diagnóstico de diente invaginado: presentación de un caso

The aim of this report is to present a case of dens invaginatus asymptomatic discovered after exam cone beam computed tomography. A 20-year-old patient attended the clinic Radiology to perform tomography to fracture research at the root of the tooth 15. However, the examination was observed the presence of a conoid supernumerary tooth between the tooth located roots 11 and 12, which had a hyperdense line to the apex of the root, representing the invagination of the enamel, dens invaginatus feature. It was also observed extensive hypodense image in the periapical region, with areas of external resorption both in supernumerary tooth as we ll as the roots of teeth 11 and 12. The treatment consisted of surgery for dens invaginatus extraction. The dentists should be aware of the imaginological characteristics of the anomalies that can affect the teeth/jaws, which can be discovered in tests for routine imaging and proper conduct for the treatment of patients.

El objetivo de este trabajo fue presentar un caso dedens invaginatusasintomático descubierto en una tomografía computarizada de haz cónico. Un paciente de 20 años de edad acudió a la clínica radiológica para realizarse una tomografía producto una fractura radicular del diente 15. Sin embargo, en el exámen se observó la presencia de un diente supernumerario cónico localizado entre las raíces de los dientes 11 y 12, observando además una línea hiperdensa hacia el ápice de la raíz, que representa la invaginación del esmalte, característica propia de undens invaginatus.También se observó un área hipodensa en la región periapical, con áreas de reabsorción externa tanto en el diente supernumerario como en las raíces de los dientes 11 y 12. El tratamiento consistió en cirugía de extracción deldens invaginatus. Los dentistas deben conocer las características imagenológicas de las anomalías que pueden afectar a los dientes, las cuales pueden ser descubiertas en exámenes de rutina y también el protocolo adecuado de tratamiento de éstas.

Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats

Abstract The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues.

Comparison of palatal bone height in different facial morphological patterns by cone beam computed tomography

Abstract Aim: To evaluate the relationship between palatal bone height and facial types using cone beam computed tomography (CBCT) images. Methods: The study sample consisted of 110 CBCT images. Subjects aged 18 to 35 years old were classified as brachyfacial, mesofacial and dolichofacial, according to SN.GoGn angle, measured in cephalometric analysis with Nemotec 3D software. Three observers evaluated the bone height of the palate in the anterior region, at the level of the maxillary first premolars. The measurements were performed in sagittal and coronal views, in median and paramedian regions of the palate, also using Nemotec 3D software. Measurements were repeated after 15 days on 25% of the sample to analyse intra and interobserver agreements by CCI test. Analysis of variance was performed to calculate statistical differences between the bone heights of the three facial types, with a significance level of 5%. Results: The correlation level of intra-observer agreement was excellent. No significant differences were observed between the palatal bone height in the region of first premolars and the different facial types (p>0.05). Conclusions: Based on CBCT evaluations, there is no association between palatal bone height and facial morphological patterns.

2D and 3D imaging of the relationship between maxillary sinus and posterior teeth

Aim: To compare the qualitative and quantitative information yielded by imaging modalities on the evaluation of the relationship between the maxillary sinus and the apices of posterior teeth. Methods: Three oral radiologists examined 109 panoramic radiographs and cone-beam computed tomography (CBCT) images obtained from a digital archive. A total of 1,875 apices were classified according to their topographic relationship in both imaging modalities. Agreements between the two imaging techniques were examined statistically. The evaluation was repeated in 25% of the sample to statistically evaluate the intraobserver agreement, with a 30-day interval. Results: The values found in the Kappa test for qualitative assessment and the intraclass correlation coefficient (ICC) for quantitative assessment showed nearly perfect and excellent correlation, respectively. Regarding the correlation between the two images, the Kappa test in the quality assessment showed a slight correlation between the palatal roots of the right first molars and second molars. Moreover, the quantitative evaluation by ICC showed poor agreement for the palatal roots of the left first molar and second molar, as well as for the buccomesial of the right second molars and for the buccodistal of the left second molars.Conclusions: There is low correlation between panoramic radiography and CBCT when roots are in contact or above the maxillary sinus floor. A high level of agreement was observed when roots are below the maxillary sinus floor.

Utilización del prototipado rápido en la odontología / The use of rapid prototyping in dentistry

Nuevas técnicas van acompañando la evolución de la odontología y buscan superar obstáculos presentes en la actualidad. El prototipado rápido (PR) fue insertado en el medio odontológico con el propósito de auxiliar procedimientos, minimizar riesgos y disminuir el tiempo quirúrgico. A partir de exámenes tomográficos y de resonancia magnética, son creados diseños asistidos por medio de un computador específico, luego de ello son transformados en un lenguaje propio, para que a partir de ahí, estos diseños sean transformados en objetos físicos en 3 dimensiones (prototipos), fieles al modelo inicial hecho en la computadora. Existen muchas técnicas para la confección de los modelos 3D, variando el tipo de material que se añadirá, por el proceso de adición en capas. Muchas son las áreas beneficiadas por el PR; sin embargo, cirugia, implantología, prótesis y ortodoncia, asimilaron más los principios de esta técnica la cual está ayudando de manera significativa en su práctica diaria. Los beneficios del PR son numerosos, sea en la disminución de riesgos quirúrgicos, precisión de maniobras, disminución de tiempo transoperatorio, estética en los procedimientos y hasta en la comunicación entre el cirujano dentista y el paciente. Las desventajas de la técnica incluyen el elevado costo inicial y un considerable tiempo de preparación del prototipado. Lo que se viene observando es que el PR se está convirtiendo cada vez más de uso cotidiano odontológico y sus beneficios superan algunas desventajas aún persistentes...

New techniques have been accompanying the development of dentistry and seek to overcome obstacles present nowadays. The Rapid Prototyping (RP) was inserted into the dentistry in order to assist procedures, minimize risk and reduce the surgical time. From Computed Tomography exams and Magnetic Resonance, are been created design assisted by a specific computer, then processed in its own language; so from there, such designs are transformed into physical objects in 3 dimensions (prototype), trusted in the initial model created in the computer. There are many techniques for production of 3D models, varying the type of material that will be added by the process of adding layers. Many areas were benefited by the PR, however Surgery, Implantology, Orthodontics and Prosthodontics, absorbed the principles of this technique which is helping significantly in their daily practice. The benefits of PR are undisputed, whether in the reduction of surgical risks, precision maneuvers, and gain time in the trans-operative period, cosmetic procedures and in the communication between the dentist and the patient. The disadvantages of the technique are also reported as high initial cost and considerable time preparing the prototype. What has been observed is that this PR is becoming increasingly present in the dental practice and the benefits are overcoming some disadvantages still persistent...

La tomografía computarizada cone beam en la ortodoncia, ortopedia facial y funcional / Cone beam computed tomography use in orthodontics, functional facial orthopedics

La Tomografía Computarizada Cone Beam (TCCB) es una tecnología en rápido desarrollo que proporciona imágenes de alta resolución espacial del complejo craneofacial en tres dimensiones (3D). Durante la última década, el número de publicaciones relacionadas a la TCCB en la literatura se ha incrementado de manera significativa, pero la cuestión fundamental es si esta tecnología conduce a mejores resultados. La TCCB y su aplicación en la ortodoncia es muy importante ya que esta nueva tecnología va evolucionando cada vez más rápido y nuevas imágenes se necesitan para responder algunos casos como los de recidiva. La imagen tomográfica nos va permitir tener una visión diferente comparando con las imágenes convencionales, y esta visión va de la mano con los movimientos realizados para la corrección de la maloclusión o desproporción facial...

Cone Beam Computed Tomography (CBCT) is a rapidly evolving technology that provides high spatial resolution of the craniofacial complex in three dimensions (3D). During the last decade, the number of publications related to CBCT in the literature has increased significantly, but the fundamental question is whether this technology leads to better results. CBCT and the application in orthodontics is very important as this new technology evolves ever faster and new images are needed to answer some cases, for example cases of recurrence. The tomographic image will allow us to give a different view compared to conventional images, and this view goes hand in hand with the movements for correcting malocclusion or facial disproportion...

Digital panoramic radiography for diagnosis of the temporomandibular joint: CBCT as the gold standard

Three-dimensional imaging modalities have been reported to be more accurate than panoramic radiographs (PR) for the assessment of bone components of the temporomandibular joint (TMJ). No exact prior information is available that demonstrates which specific limitations occur in terms of TMJ diagnosis when using PR for this purpose. This study aimed to assess the clinical validity of digital panoramic radiography (DPR) when diagnosing morphological disorders of the TMJ using cone-beam computed tomography (CBCT) images as the gold standard. A sample composed of TMJ images (N = 848), including 212 DPR and 212 CBCT images obtained from the same patient, was used to assess any morphological changes in the TMJ. Four appraisers diagnosed all of the DPR images, whereas the CBCT images were used to establish the gold standard. The reliability of each appraiser’s response pattern was analyzed using the Kappa test (κ), and diagnostic tests were performed to assess each appraiser’s performance using a significance level setting of 5% (α = 0.05). Reliability of each appraiser’s response pattern compared to the gold standard ranged from a slight-to-moderate agreement (0.18 ≤ κ ≤ 0.45); and among the different appraisers, the response pattern showed a fair agreement (0.22 ≤ κ ≤ 0.39). Diagnostic tests showed a wide range among the different possible morphological changes diagnosed. DPR does not have validity when diagnosing morphological changes in the TMJ; it underestimates the radiological findings with higher prevalence, and thus, it cannot be used effectively as a diagnostic tool for bone components within this region.

Aspectos tomográficos de ameloblastoma multicístico de células granulares: relato de caso / Computed tomography imaging features of multicystic granular cell ameloblastoma: a case report

O ameloblastoma multicístico é uma variante clínica do ameloblastoma, muitas vezes localmente agressivo, com significante aumento de morbidade e mortalidade. O ameloblastoma é frequentemente assintomático, sendo identificado incidentalmente durante exames odontológicos de rotina. Trata-se de uma lesão de crescimento lento e persistente, podendo ser notada, em alguns casos, uma expansão gradual da mandíbula, produzindo assimetria facial. Ameloblastomas raramente apresentam um comportamento maligno. A avaliação clínica inclui uma revisão cuidadosa da história clínica do paciente, bem como exame físico da cabeça e pescoço. Modalidades de imagens radiográficas são úteis para localizar a lesão, avaliar suas dimensões e os efeitos sobre as estruturas adjacentes. O manejo da lesão representa um desafio para todos os profissionais envolvidos na área de cirurgia de cabeça e pescoço. Assim, o objetivo deste trabalho foi descrever as características tomográficas de um ameloblastoma multicístico de células granulares em um paciente do sexo masculino, leucoderma, de 40 anos de idade...

Multicystic ameloblastoma is a clinical variant of ameloblastoma. It is often locally aggressive with significant impact on patient morbidity and mortality. Ameloblastoma is often asymptomatic and is usually detected as an incidental finding during routine dental examinations. It presents slow and persistent growth; in some cases a gradual expansion of the jaw producing facial asymmetry may be noticed . Although the occurrence is rare, ameloblastomas can exhibit malignant behavior and metastasize. Clinical evaluation includes careful review of the patient's medical history and physical examination of the head and neck region. Radiographic imaging techniques are useful for locating the lesion, estimating its dimensions and assessing its effects on adjacent structures. Management of ameloblastoma is a challenge for all involved in the field of head and neck surgery. The aim of this paper was therefore to describe the tomographic features of a multicystic granular cell ameloblastoma in a 40-year-old white male patient...

Oblique or orthoradial CBCT slices for preoperative implant planning: which one is more accurate?

AIM: To assess which slice inclination would be more accurate in measuring sites for implant placement: the oblique or the orthoradial slice. METHODS: Five regions of eight edentulous mandibles were selected (incisor, canine, premolar, first molar and second molar). The mandibles were scanned with a Next Generation i-CAT CBCT unit. Two previously calibrated oral radiologists performed vertical measurements in all the selected regions using both the oblique and orthoradial slices. The mandibles were sectioned in all the evaluated regions in order to obtain the gold standard. The Wilcoxon signed rank test compared the measurements obtained in the oblique and orthoradial slices with the gold standard. RESULTS: The bone height measurements for the first and second molar regions using the orthoradial slices were statistically different from the gold standard. CONCLUSIONS: Using the orthoradial slices to obtain cross-sectional images may offer insufficient accuracy for implant placement in the posterior region...

Prevalence of C-shaped root canal in a Brazilian subpopulation: a cone-beam computed tomography analysis

The aim of this study was to use cone-beam computed tomography (CBCT) images to evaluate the prevalence and configurations of C-shaped canals in permanent mandibular second molars among members of a Brazilian subpopulation. CBCT exams of 214 patients (406 teeth) were evaluated for: presence of C-shaped root canals, number of canals and direction of the root grooves (buccal or lingual). Of the 214 CBCT images examined, 192 showed intact bilateral molars, which were used to analyze the distribution of unilateral and bilateral occurrences of C-shaped canals. The prevalence of these canals was correlated with gender and age, and the number of canals was correlated with the direction of the root grooves using the chi-squared test (α = 0.05). The prevalence of C-shaped canals was 15.3%. This prevalence did not differ with gender or age. Most of the C-shaped molars had three (43.5%) or two (37.1%) canals; 69.4% of the C-shaped canals were grooved in the buccal direction; 68.3% of the C-shaped cases were unilateral. In conclusion, there was a significant prevalence of C-shaped canals in the mandibular second molars of the population studied; the C-shaped canal system varied in configuration, with a higher prevalence of three and two canals and unilateral occurrence; CBCT is a useful tool for endodontic diagnosis and treatment.

Distance learning in dental radiology: immediate impact of the implementation / Educação à distância em radiologia odontológica: Impacto imediato da implantação

Objective: This study assessed the immediate impact in terms of learning dento-maxillomandibular radiographic anatomy in intraoral periapical radiographs after entire replacement of the method of classroom learning by the distance learning using the Moodle platform. Material and Methods: Teaching of this subject by traditional educational setting in classroom was made until the first semester of 2011, “A class” (AC), using radiographic slabs from duplicated films with imprints indicating anatomical structures in images that is accompanied by textbook with its description and support teacher, who works closely with the classroom to support student learning. In the second semester of 2011, “B class” (BC), these same radiographic slabs were digitalized, including description of textbook, creating the Moodle e-course about dentomaxillomandibular anatomy in intraoral radiographs for distance learning. The impact was assessed by comparison of scores of students from two distinct classes, AC (N = 60) and BC (N = 62), after application of a similar test with all content of the topic of dento-maxillomandibular anatomy, using T-Student unpaired test (α = 0.05). A voluntary and unidentified questionnaire with 12 questions, developed in Google Docs spreadsheets, was used to evaluate the acceptance of students for this e-course. Results: No significant differences (p > 0.05) were observed in scores of the students from two classes. Among other questions, all students of BC who completed the questionnaire had interest in content of the available material in e-course, and their satisfaction level on a scale from 0 to 10 had a mean of 8.47 (SD = 1.69). Conclusion: The method of distance learning of this subject using the Moodle platform can be utilized with same educational results as of those obtained from a traditional educational setting...

Objetivo: Este estudo avaliou o impacto imediato em termos de aprendizagem da anatomia radiográfica dento-maxilo-mandibular em radiografias periapicais intrabucais, após toda a substituição do método de ensino em sala de aula pela educação a distância com a plataforma Moodle. Material e Métodos: O ensino desta disciplina no ambiente educacional tradicional em sala de aula foi feito até o primeiro semestre de 2011, classe A (AC), utilizando pranchas de filmes radiográficos duplicados com marcações que indicavam estruturas anatômicas nas imagens eum livro texto com a descrição da referida estrutura, além de professor de apoio, que trabalhava na sala de aula junto com os alunos como apoio de aprendizagem. No segundo semestre de 2011, para a “classe B” (BC), essas mesmas pranchas radiográficas foram digitalizadas, incluindo a descrição do livro texto, para criar o curso digital Moodle sobre anatomia dentomaxilo- mandibular em radiografias intra-orais para educação a distância. O impacto dessa substituição foi avaliado pela comparação das notas dos alunos dessas duas classes distintas, AC (N= 60) e BC (N = 62), após a aplicação de uma prova semelhante com todo o conteúdo do tema da anatomia dentomaxilo- mandibular, utilizando teste T-Student não pareado (α = 0,05). Um questionário voluntário e não identificado com 12 questões, desenvolvido em planilhas do Google Docs, foi utilizado para avaliar a aceitação dos alunos em relação ao curso digital. Resultados: Não houve diferença significativa (p > 0,05) entre as notas dos alunos das duas classes. Em relação às respostas do questionário, todos os alunos da BC que responderam ao questionário tinham interesse no conteúdo do material disponível no curso digital e o nível de satisfação medido em uma escala de 0 a 10 obteve média de 8,47 (DP = 1,69)...

Gardner's syndrome suggested by radiographic findings / Síndrome de Gardner sugerida por achados radiográficos

Gardner's syndrome (GS) is a hereditary disorder characterized by multiple osteomas, enostosis, epidermoid cysts, subcutaneous desmoid tumors and multiple gastrointestinal polyps. Given the variety of clinical manifestations, the triad of symptoms that better characterizes the GS is composed by polyps of the colon, multiple osteomas and tumors of soft tissue. The osteomas are most common in the frontal bone and mandible. A significant feature of GS is the progression to malignancy of the intestinal polyps in almost 100% of patients. Early detection of GS allows for an excellent prognosis and may be a lifesaving event. Thus, the aim of this case report was to describe the radiographic aspects of GS in the dentomaxillofacial region and to discuss with the current scientific literature.

A síndrome de Gardner (SG) é uma desordem caracterizada por múltiplos osteomas, enostosis, cistos epidermoides, tumores desmoides subcutâneos e múltiplos pólipos gastrointestinais. Considerando a variedade de manifestações clínicas, a tríade dos sintomas que melhor caracterizam a SG é composta por pólipos do cólon, múltiplos osteomas e tumores de tecido mole. Os osteomas são mais comuns no osso frontal e mandíbula. Uma característica significativa da SG é a progressão maligna dos pólipos intestinais em aproximadamente 100% dos pacientes. A detecção precoce da SG favorece um excelente prognóstico e pode salvar vidas. Então, o objetivo deste relato de caso foi descrever os aspectos radiográficos da SG na região dento-maxilo-facial e discutir com a literatura científica atual.

Evaluation of condyle defects using different reconstruction protocols of cone-beam computed tomography

This study was conducted to investigate how well cone-beam computed tomography (CBCT) can detect simulated cavitary defects in condyles, and to test the influence of the reconstruction protocols. Defects were created with spherical diamond burs (numbers 1013, 1016, 3017) in superior and/or posterior surfaces of twenty condyles. The condyles were scanned, and cross-sectional reconstructions were performed with nine different protocols, based on slice thickness (0.2, 0.6, 1.0 mm) and on the filters (original image, Sharpen Mild, S9) used. Two observers evaluated the defects, determining their presence and location. Statistical analysis was carried out using simple Kappa coefficient and McNemar's test to check inter- and intra-rater reliability. The chi-square test was used to compare the rater accuracy. Analysis of variance (Tukey's test) assessed the effect of the protocols used. Kappa values for inter- and intra-rater reliability demonstrate almost perfect agreement. The proportion of correct answers was significantly higher than that of errors for cavitary defects on both condyle surfaces (p < 0.01). Only in identifying the defects located on the posterior surface was it possible to observe the influence of the 1.0 mm protocol thickness and no filter, which showed a significantly lower value. Based on the results of the current study, the technique used was valid for identifying the existence of cavities in the condyle surface. However, the protocol of a 1.0 mm-thick slice and no filter proved to be the worst method for identifying the defects on the posterior surface.

Radioprotective Effect of Sodium Selenite on Developing Teeth

Radioprotective agents like selenium are used to reduce the damage caused by radiation in healthy tissues. The aim of this study was to evaluate the effect of sodium selenite on the development of the molars of offspring of rats irradiated during odontogenesis. Twenty pregnant rats were randomly divided into 4 groups: control, irradiated, selenium and selenium/irradiated. The selenium and selenium/irradiated groups received 0.3 mg/kg of sodium selenite at 18 days of pregnancy. The rats of the irradiated and selenium/irradiated groups received a single dose of 4 Gy of X rays on the abdominal region at the 19th day of pregnancy. The offspring was sacrificed at 3 and 4 days after birth for evaluation of the birefringence of the enamel organic matrix, and at 30 days for evaluation of the intercuspal dimensions of the molars. The selenium/irradiated group was similar to the irradiated group with respect to the thickness and irregularity of the enamel organic matrix region in the evaluated birefringence, as the intercuspal dimensions of the molars. In conclusion, sodium selenite had no radioprotective action on the development of the molars of offspring of rats irradiated during odontogenesis and had a toxic effect in the initial time.

Agentes radioprotetores, como o selênio, são utilizados para reduzir os danos causados pela radiação nos tecidos sadios. O objetivo nesse estudo foi avaliar o efeito do selenito de sódio no desenvolvimento de molares de filhotes de ratas irradiadas. Vinte ratas grávidas foram aleatoriamente divididas em 4 grupos: controle, irradiado, selênio e selênio/irradiado. Os animais dos grupos selênio e selênio/irradiado receberam 0.3 mg/kg de selenito de sódio aos 18 dias de gestação. Os animais dos grupos irradiado e selênio/irradiado receberam dose única de 4 Gy de radiação X na região abdominal aos 19 dias de gestação. Os filhotes foram sacrificados aos 3 e 4 dias após o nascimento para avaliação da birrefringência da matriz orgânica do esmalte, e aos 30 dias para avaliação das dimensões dos molares. Os resultados do grupo selênio/irradiado foram similares aos do irradiado, tanto em relação à espessura e irregularidade região da matriz orgânica do esmalte quanto às dimensões dos molares. Dessa forma, foi possível concluir que o selenito de sódio não exerceu ação radioprotetora no desenvolvimento de molares de filhotes de ratas irradiadas durante a odontogênese e apresentou efeito tóxico nos tempos iniciais.

Radioprotective Effect of Vitamin E in Parotid Glands: a Morphometric Analysis in Rats

The aim of this study was to evaluate the radioprotective effect of vitamin E on rat parotid glands by morphometric analysis. Sixty male rats were divided into 5 groups (n=6): control, in which animals received olive oil solution; olive oil/irradiated, in which animals received olive oil and were irradiated with a dose of 15 Gy of gamma radiation; irradiated, in which animals were irradiated with a dose of 15 Gy gamma radiation; vitamin E, which received α-tocopherol acetate solution; vitamin E/irradiated, which received α-tocopherol acetate solution before irradiation with a dose of 15 Gy gamma rays. Half of the animals were euthanized at 8 h, and the remaining at 30 days after irradiation. Both parotid glands were surgically removed and morphometric analysis of acinar cells was performed. Data were subjected to two-way ANOVA and Tukey's test (α=0.05). Morphometric analysis showed a significant reduction in the number of parotid acinar cells at 30 days in olive oil/irradiated and irradiated groups. In groups evaluated over time a significant reduction was shown at 30 days in olive oil/irradiated and irradiated groups, indicating that ionizing radiation caused tissue damage. The vitamin E/irradiated group presented more acinar cells than the irradiated group, but no statistically significant difference was observed (p>0.05). In conclusion, vitamin E seems to have failed as a radioprotective agent on acinar cells in rat parotid glands.

O objetivo neste estudo foi avaliar o efeito radioprotetor da vitamina E sobre glândulas parótidas de ratos por meio de análise morfométrica. Sessenta ratos machos foram divididos em cinco grupos: controle, no qual os animais receberam solução de óleo de oliva; óleo de oliva irradiado, em que os animais receberam óleo de oliva e foram irradiados com uma dose de 15 Gy de radiação gama; irradiado, em que os animais foram irradiados com uma dose de 15 Gy de radiação gama; vitamina E, no qual receberam solução de acetato α-tocoferol; vitamina E irradiado, os quais receberam solução de acetato de α-tocoferol antes da irradiação com uma dose de 15 Gy de radiação gama. Metade dos animais foi eutanasiada em 8 h, e o restante aos 30 dias após a irradiação. Ambas as glândulas parótidas foram removidas cirurgicamente e análise morfométrica das células acinares foi realizada. Os dados foram submetidos à Análise de Variância com 2 fatores e teste de Tukey (α=0,05). A análise morfométrica mostrou uma redução significativa no número de células acinares da glândula parótida aos 30 dias nos grupos óleo irradiado e irradiado. Nos grupos avaliados ao longo do tempo uma redução significativa foi mostrada aos 30 dias nos grupos óleo irradiado e irradiado, indicando que a radiação ionizante causou danos teciduais. O grupo vitamina E/irradiado apresentou mais células acinares que o grupo irradiado, mas diferença estatisticamente significante não foi observada. Em conclusão, a vitamina E parece ter fracassado como um agente radioprotetor nas células acinares das glândulas parótidas de ratos.

Bone density: comparative evaluation of Hounsfield units in multislice and cone-beam computed tomography

The aim of this study was to evaluate the validity of the bone density value of potential implant sites in HU obtained by a specific cone-beam computed tomography (CBCT) device. In this study, the HU values obtained using a MSCT scanner were used as the gold standard. Twenty mandibles (40 potential implant sites) were scanned using an MSCT scanner (Somatom Sensation 40) and a CBCT scanner (i-CAT). The MSCT images were evaluated using the Syngo CT Workplace software and the CBCT images, using the XoranCat software. The images were evaluated twice by three oral radiologists, at 60 day intervals. The trabecular bone density of the same area was evaluated on both images. Intraclass coefficients (ICC) were calculated to examine the agreement between the examiners and between the two periods of evaluation. The bone density and area of the ROI were compared by the Student t test and Bland-Altman analysis. ICCs were excellent. The mean HU value obtained using CBCT (418.06) was higher than that obtained using MSCT (313.13), with a statistically significant difference (p < 0.0001). In addition, Bland-Altman analysis showed that the HU measures were not equivalent. In conclusion, the bone density in HU with CBCT images obtained using the device studied proved unreliable, since it was higher than that obtained using MSCT.

Gray scale inversion in digital image for measurement of tooth length

The aim of this study was to assess the applicability of gray scale inversion in performing digital linear endodontic measurements. Standardized digital images were taken of 40 extracted human permanent single-rooted teeth with K-files size 15 placed at different lengths in the root canal, using the CDR Wireless® digital system. All images were treated with Positive, a digital tool that inverts the grayscale value. Eight radiologists measured the distance between the lower limit of the rubber stop and the tip of the file on both original and positive images. After 15 days, they repeated this procedure in 50% of the image samples. The intra- and inter-examiner agreement was analyzed by intraclass correlation test, and the comparison between the two image groups and the actual lengths by the Student's t-test (α=0.05). Intra- and inter-examiner evaluation showed high reproducibility (r>0.95) of both original and positive images. No statistically significant differences (p>0.05) were found between measurements performed on original and positive images, but both differed significantly from the actual lengths (p<0.05). Gray scale inversion has low applicability in measuring endodontic files, since it did not improve the accuracy of measurements.

O objetivo deste estudo foi avaliar a aplicabilidade da inversão da escala de cinza na realização de mensurações endodônticas lineares digitais. Quarenta dentes unirradiculares humanos extraídos foram radiografados com limas K tamanho 15 posicionadas no canal radicular em diferentes comprimentos, usando o sistema digital CDR Wireless®. Todas as imagens foram tratadas com Positive, uma ferramenta digital que inverte os valores da escala de cinza. Oito radiologistas mediram a distância entre o limite inferior do stop de borracha e a ponta da lima endodôntica nas imagens originais e positivas. Após quinze dias, eles repetiram esse procedimento em 50% da amostra. A concordância intra- e interobservador foi analisada pelo teste de correlação intraclasse e a comparação entre os dois grupos de imagem e os valores reais, pelo teste t-Student (α=0,05). A análise intra- e interobservador apresentou elevada reprodutibilidade (r>0,95) das imagens original e Positive. Não foi encontrada diferença (p>0,05) entre as medidas realizadas nas imagens original e positiva, mas ambas diferiram dos valores reais (p<0,05). A inversão da escala de cinza tem baixa aplicabilidade na realização de mensuração endodôntica, considerando que as medidas não se apresentaram mais acuradas.

Radioprotective effect of sodium selenite on bone repair in the tibia of ovariectomized rats

This studyevaluated protection by selenium (Se) in the bone repair process in ovariectomized rats after irradiation. For such purpose, 80 ovariectomized female Wistar rats were randomly divided into 4 experimental groups: ovariectomized (Ov), Ov/Se, Ov/irradiated (Irr) and Ov/ Se/Irr. A bone defect was created on the tibia of all animals 40 days after ovariectomy. Two days after surgery, only the Ov/Se and Ov/Se/Irr rats received 0.8 mg Se/kg. Three days after surgery, only the Ov/Irr and Ov/Se/Irr rats received 10 Gy of x-rays on the lower limb region. The animals were euthanized at 7, 14, 21 and 28 days after surgery to assess the repair process, which was evaluated by analysis of trabecular bone number (Masson Trichrome) and birefringence analysis (Picrosirius). It was possible to observe a delay in the bone repair process in the ovariectomized/irradiated group and similarity between the ovariectomized, Ov/Se and Ov/Se/Irr groups. In conclusion, sodium selenite exerted a radioprotective effect in the bone repair of tibia of ovariectomized rats without toxicity.

Esse estudo avaliou a proteção do selênio no processo de reparação óssea em ratas ovariectomizadas após irradiação. Para isso, 80 ratas Wistar foram divididas aleatoriamente em 4 grupos experimentais: ovariectomizado, ovariectomizado/selênio, ovariectomizado/irradiado e ovariectomizado/selênio/irradiado. Foi realizado um defeito ósseo na tíbia de todos os animais 40 dias após ovariectomia. Dois dias após essa cirurgia, os animais dos grupos ovariectomizado/selênio e ovariectomizado/selênio/irradiado receberam 0,8 mg Se/kg. Três dias após a cirurgia, os animais dos grupos ovariectomizado/irradiado e ovariectomizado/selênio/irradiado receberam 10 Gy de radiação X na região de membros inferiores. Os animais foram sacrificados 7, 14, 21 e 28 dias após a cirurgia para avaliação do processo de reparo ósseo, que foi realizado pela análise do número de trabéculas ósseas (coloração Tricrômico de Masson) e pela análise de birrefringência (coloração de Picrosirius). Foi observado atraso no processo de reparo ósseo no grupo ovariectomizado/irradiado e semelhança entre os grupos ovariectomizado, ovariectomizado/selênio e ovariectomizado/selênio/irradiado. Foi possível concluir que o selenito de sódio exerceu efeito radioprotetor no processo de reparação de tíbias em ratas ovariectomizadas sem toxicidade.