Effect of different exposure times on caries detection and pixel value in a wireless digital system.

OBJECTIVES: : The aim of this study was to assess, using the CDR Wireless®, the effect of different exposure times on caries detection and pixel intensity values. MATERIALS AND METHODS: Forty teeth were x-rayed using a Schick CDR Wireless sensor at eight different exposure times - 0.06, 0.10, 0.13, 0.16, 0.20, 0.25, 0.30, and 0.32 s. Four observers evaluated the images for presence of carious lesions scoring proximal surfaces of each tooth on a 5-point scale. Scores were compared to histological sections of the teeth. Accuracy was evaluated by means of ROC curve analysis. Radiographs of an aluminum step wedge were obtained using the same eight exposure times. Pixel intensity measurements were obtained, and mean pixel values were statistically analyzed using linear regression. RESULTS: The Az for each exposure time varied from 0.53 to 0.62. Two-way analysis of variance and Tukey test demonstrated that the exposure time of 0.25 s presented the best result and was significantly higher than 0.30 s and 0.35 s. In regard to mean pixel values, two different behaviors were observed, and the exposure time of 0.20 s presented mean pixel values in both phases. CONCLUSION: The performance of the exposure times from 0.06 s to 0.25 s was satisfactory for proximal caries detection, and 0.25 s is the best as indicated for this finality. CLINICAL RELEVANCE: Considering that a reduction of exposure time represents a reduction of patient exposure dose, and this reduction cannot neglect image quality, the behavior of any digital system must be carefully evaluated.

Diagnostic accuracy of phosphor plate systems and conventional radiography in the detection of simulated internal root resorption.

OBJECTIVE: To evaluate the performance of conventional radiography and photostimulable phosphor (PSP) plate in the detection of simulated internal root resorption (IRR) lesions in early stages. MATERIALS AND METHODS: Twenty single-rooted teeth were X-rayed before and after having a simulated IRR early lesion. Three imaging systems were used: Kodak InSight dental film and two PSPs digital systems, Digora Optime and VistaScan. The digital images were displayed on a 20.1″ LCD monitor using the native software of each system, and the conventional radiographs were evaluated on a masked light box. Two radiologists were asked to indicate the presence or absence of IRR and, after two weeks, all images were re-evaluated. Cohen's kappa coefficient was calculated to assess intra- and interobserver agreement. The three imaging systems were compared using the Kruskal-Wallis test. RESULTS: For interexaminer agreement, overall kappa values were 0.70, 0.65 and 0.70 for conventional film, Digora Optima and VistaScan, respectively. Both the conventional and digital radiography presented low sensitivity, specificity, accuracy, positive and negative predictive values with no significant difference between imaging systems (p = .0725). CONCLUSIONS: The performance of conventional and PSP was similar in the detection of simulated IRR lesions in early stages with low accuracy.

MicroCT assessment of bone microarchitecture in implant sites reconstructed with autogenous and xenogenous grafts: a pilot study.

PURPOSE: To assess bone microarchitecture in maxillary sites grafted with autogenous or xenogenous grafts as well as to demonstrate the usefulness of microCT in dental implant research. MATERIALS AND METHODS: Samples (n = 12) consisting of titanium fixation screws covered by at least 0.5-1 mm of human bone were obtained from 17 sites grafted with autogenous or xenogenous materials and prepared for microCT scanning and conventional histology. Bone histomorphometric parameters were evaluated in three distinct regions (graft region, transitional region, and native bone region). Three-dimensional (3D) bone-to-implant contact (BIC) calculation was performed using microCT data. Histological sections were used to calculate two-dimensional (2D) BIC percentages, which were compared with values obtained from 2D microCT images. RESULTS: Histomorphometric parameters varied according to the type of graft used, but sites reconstructed with autogenous bone showed higher mean values in general. In autograft samples, indices for parameters such as Tb.Th and Tb.Sp were significantly different when the native bone region was compared to the graft region. While a higher mean 3D BIC was found in the native bone region for both graft materials, significant BIC differences were absent when graft types were compared. The 2D BIC percentages obtained from histological and microCT images were similar. CONCLUSIONS: Autografts outperformed the xenogenous material used in this study concerning the histomorphometric parameters assessed. While graft type did not seem to influence 3D BIC, the native bone region showed the highest BIC percentages when compared to the other regions in both graft groups. In addition, 2D BIC ratios were similar regardless of graft material or image source (histological sections x microCT slices). Taken together, our findings suggest that microCT is an effective tool for 2D and 3D histomorphometric and BIC assessments in dental implant research.

Association between maxillary sinus pathologies and healthy teeth / Relação entre doenças no seio maxilar e dentes hígidos

ABSTRACT INTRODUCTION: The proximity of the roots to the maxillary sinus can create a variety of risks. OBJECTIVE: To evaluate the relationship between the roots of healthy teeth and the maxillary sinus, as well as the occurrence of sinus pathologies. METHODS: Three radiologists analyzed 109 cone beam computed tomography (CBCT) images. The Kappa test was used to assess the intra- and inter-rater agreement. The chi-squared test and prevalence ratio were used to test the hypothesis that roots of healthy teeth in the maxillary sinus favored the occurrence of sinus pathologies ( p = 0.01). RESULTS: Intra- and inter-rater agreement ranged from good to excellent. The chi-squared test demonstrated a statistically significant difference ( p = 0.006) between the tooth roots in diseased maxillary sinuses (6.09%) and those in normal sinuses (3.43%). The prevalence ratio test showed a statistically significant higher prevalence of tooth roots in diseased sinuses than in normal sinuses ( p < 0.0001). Roots in the maxillary sinus were 1.82 times more associated with diseased sinuses. CONCLUSION: Dental roots in the maxillary sinus are almost twice as likely to be associated with diseased sinuses than normal sinuses. Healthy teeth whose roots are inside the maxillary sinus may induce an inflammatory response in the sinus membrane. It is suspected that dental procedures may exacerbate the condition.

RESUMO INTRODUÇÃO: A proximidade das raízes com o seio maxilar pode criar uma variedade de riscos. OBJETIVO: Avaliar a relação entre as raízes dos dentes hígidos com o seio maxilar, assim como com a ocorrência de doenças sinusais. MÉTODO: Três radiologistas analisaram 109 imagens de tomografia computadorizada de feixe cônico (TCFC). O teste Kappa avaliou a concordância intra e interexaminadores. Os testes de Qui-quadrado e Razão de Prevalência foram utilizados para testar a hipótese de que raízes de dentes hígidos dentro do seio maxilar favorecem a ocorrência doenças sinusais (nível de significância = 0,01). RESULTADOS: A concordância intra e interexaminadores variou de boa a excelente. O teste Qui-quadrado mostrou uma diferença estatisticamente significante (p = 0,006) entre as raízes dentárias dentro do seio maxilar patológico (6,09%) e aquelas dentro do seio normal (3,43%). O teste de Razão de Prevalência mostrou uma ocorrência de raízes dentárias dentro de seios patológicos estatisticamente maior do que dentro de seios normais (p < 0,0001). As raízes dentro do seio maxilar foram encontradas 1,82 vezes mais associadas a seios patológicos. CONCLUSÃO: Raízes dentárias dentro do seio maxilar são quase duas vezes mais associadas a seios patológicos do que a seios normais. Dentes hígidos que têm raízes dentro do seio maxilar podem induzir uma resposta inflamatória da mucosa sinusal. Suspeita-se que procedimentos odontológicos possam agravar tal situação.

Association between maxillary sinus pathologies and healthy teeth.

INTRODUCTION: The proximity of the roots to the maxillary sinus can create a variety of risks. OBJECTIVE: To evaluate the relationship between the roots of healthy teeth and the maxillary sinus, as well as the occurrence of sinus pathologies. METHODS: Three radiologists analyzed 109 cone beam computed tomography (CBCT) images. The Kappa test was used to assess the intra- and inter-rater agreement. The chi-squared test and prevalence ratio were used to test the hypothesis that roots of healthy teeth in the maxillary sinus favored the occurrence of sinus pathologies (p=0.01). RESULTS: Intra- and inter-rater agreement ranged from good to excellent. The chi-squared test demonstrated a statistically significant difference (p=0.006) between the tooth roots in diseased maxillary sinuses (6.09%) and those in normal sinuses (3.43%). The prevalence ratio test showed a statistically significant higher prevalence of tooth roots in diseased sinuses than in normal sinuses (p<0.0001). Roots in the maxillary sinus were 1.82 times more associated with diseased sinuses. CONCLUSION: Dental roots in the maxillary sinus are almost twice as likely to be associated with diseased sinuses than normal sinuses. Healthy teeth whose roots are inside the maxillary sinus may induce an inflammatory response in the sinus membrane. It is suspected that dental procedures may exacerbate the condition.

Racionalización de la dosis de radiación / Streamlining the radiation dose

En la actualidad existe una gran aceptación por la medicina y la odontología, en que la práctica clínica debe ser ôbasada en evidencia científicaõ, tanto como sea posible. Es por eso que múltiples trabajos se han publicado orientados a disminuir las dosis de radiación en los diferentes tipos de modalidades imaginológicas usados en la odontología, ya que el mayor efecto de las radiaciones, sobre todo en niños, nos obliga a tomar medidas necesarias para racionalizar su uso, especialmente con la tomografía computarizada Cone Beam (TCCB), método que aporta las mayores dosis en la odontología. Esta revisión fue escrita utilizando un enfoque de este tipo con el propósito de racionalizar la dosis de radiación en nuestros pacientes. El equipo del proyecto SEDENTEXCT recopiló y analizó relevantes publicaciones en la literatura, pautas que han demostrado su eficacia en el pasado, para llegar a formular recomendaciones que contribuyan a la optimización del uso de las radiaciones ionizantes en la odontología, ayudando de esa manera a ver con otros ojos la dosis recibida por los pacientes, y con la presente se recomienda tener en cuenta dicho documento para poder prescribir de manera más adecuada los exámenes complementarios que usamos diariamente...

There is now wide acceptance in medicine and dentistry that clinical practice should be as ôevidence-basedõ as possible. Which is why many works have been published aimed at reducing radiation doses in different types of imaging modalities in dentistry, and that the major effect of radiation especially in children requires us to take necessary steps to rationalize their use especially the Cone Beam Computed Tomography (CBCT) method that provides the highest doses in dentistry. This review was written using this approach because of the purpose of streamlining the radiation dose in our patients. SEDENTEXCT team collected and analyzed relevant publications in the literature, guidelines that have proven effective in the past to reach recommendations, which can contribute to optimizing the use of ionizing radiation in dentistry, helping to see with others eyes the dose received by our patients. This paper recommend to consider the SEDENTEXCT project to prescribe more appropriately complementary exams we use daily...

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...

Ionizing radiation effects on the secretory-stage ameloblasts and enamel organic extracellular matrix.

This study assessed the effects of high doses of ionizing radiation on eruption rate, odontogenic region morphology, secretory-stage ameloblasts, and enamel organic extracellular matrix (EOECM) of rat maxillary incisors. For the study, 30 male rats were divided into three experimental groups: control (non-irradiated), irradiated by 15 Gy, and irradiated by 25 Gy. Irradiated groups received a single dose of 15 or 25 Gy of X-rays in the head and neck region. The maxillary incisor eruption rate was measured. Sections of 5-µm thickness of the maxillary incisor odontogenic regions were evaluated using bright field light microscopy. Ultrathin sections of secretory ameloblasts and their EOECM were analyzed by transmission electron microscopy (TEM). Irradiated groups showed significantly diminished eruption rate values at the 4th and at the 6th day after irradiation. Reduced optical retardation values were observed in the irradiated groups. The odontogenic region of maxillary incisors from irradiated rats exhibited altered and poorly organized preameloblasts. TEM showed degeneration areas in the secretory-stage EOECM and several autophagosomes in the secretory ameloblasts from irradiated animals. In conclusion, high radiation doses delay eruption and induce disturbances in secretory ameloblasts and EOECM of rat maxillary incisors. These findings may be associated with structural defects of mature enamel.

Comparative analysis of mandibular anatomical variations between panoramic radiography and cone beam computed tomography.

PURPOSE: The objective of this study is to compare the ability of panoramic radiography and cone beam computed tomography (CBCT) in detecting anatomical variations of the mandibular canal and mental foramen. METHODS: One hundred twenty-seven preoperative panoramic and CBCT images were evaluated. Two oral and maxillofacial radiologists investigated the presence of bifid mandibular canals and/or additional mental foramina on the right, left, or both sides of the mandible. Intra- and interobserver reliability was determined using Cohen's kappa coefficient. McNemar's test compared the prevalence of mandibular anatomical variations between panoramic radiography and CBCT. The significance level was set at 0.05. RESULTS: Additional mental foramen and bifid mandibular canal were detected in 1.2 and 7.4 % of the panoramic radiographs and 7.4 and 9.8 % of the CBCT images, respectively. The incidence of anatomical variations on the mandibular canal was not significantly different between both imaging modalities (P > 0.05). CONCLUSIONS: Although CBCT provides better viewing of anatomical structures, including location, shape, and relationship with the surrounding area, panoramic radiography is a conventional imaging modality that can be used in the study of the bifid mandibular canals.

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.

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.

Radiopacity assessment of composite resins through digital systems and InSight intraoral film / Avaliação da radiopacidade de resinas compostas por meio de sistemas digitais e filme radiográfico InSight

Objective: this study aimed to assess the radiopacity of eight composite resins recommended for class II restorations. Materials and method: hence, 2 mm thick and 4 mm in diameter test specimens were made and compared to enamel, dentin, and aluminum using four digital systems: two semi-direct by storage phosphor image plates (SPIP) - Digora™, and DenOptix™, two charged couple devices (CCD) - Sens-A-Ray™ and Computerized Dental Radiograph (CDR™), and radiographic film Kodak Insight IS-21™. The radiographs were scanned to obtain the indirect digital image, and along with direct and semi-direct digital images the radiographic densities were assessed in specific software. The pixel values from the aluminum step wedge were submitted to a linear regression from where the equivalent in millimeters for enamel, dentin, and resins were determined. Results: density means of resins were equal or superior to the means obtained for enamel in all digital systems and the conventional film. SureFil™ resin presented greater numerical radiopacity in all digital systems and the radiographic film. ALERT™ resin showed the smallest radiopacity among the studied resins in all digital systems and radiographic film. ALERT™ and Definite™ were statistically equivalent to enamel in the Sens-A-Ray™ system and in radiographic film. The remaining resins (Charisma™, FillMagic™, P60™, Prodigy™, SureFil™, and Z250™) presented higher radiopacities in comparison to enamel. Only ALERT™ presented radiopacity similar to enamel in other digital systems (CDR™, DenOptix™, and Digora™). In these digital systems, Charisma™, Definite™, FillMagic™, P60™, Prodigy™, SureFil™, and Z250™ were more radiopaque than enamel. Conclusion: all resins showed equal or higher radiopacities of enamel in all assessment systems. There was a statistical correlation between systems CDR™ and Sens-A-Ray™, and between Digora™ and DenOptix™; Sens-A-Ray™ also showed correlation with radiographic film. The percentage of density means equivalent to aluminum millimeters for enamel and dentin were 119.6% and 101.6%, respectively.

Objetivo: este estudo teve como objetivo avaliar a radiopacidade de oito tipos de resinas compostas indicadas para restaurações de classe II. Materiais e método: para tanto foram confeccionados corpos de prova de 2 mm de espessura e 4 mm de largura, os quais foram comparados com esmalte, dentina e alumínio, utilizando- se quatro sistemas digitais, sendo dois semidiretos por placas de fósforo fotoestimuladas - Digora® e DenOptix ®, dois CCD - Sens-A-Ray® e CDR®, e também o filme radiográfico Kodak Insight IS-21®. As radiografias foram escaneadas, obtendo-se imagem digital indireta, e, juntamente com as imagens digitais diretas e semidiretas, suas densidades radiográficas foram avaliadas em software específico. Os valores de pixel da escala de alumínio foram submetidos a uma regressão linear, de onde se pôde obter o equivalente em milímetros para o esmalte, dentina e resinas. Resultados: para todos os sistemas digitais e para o filme convencional, as médias das densidades das resinas foram iguais ou superiores às médias obtidas pelo esmalte. Para todos os sistemas digitais e para o filme radiográfico, a resina Surefil® apresentou maior radiopacidade numérica. A resina ALERT® apresentou a menor radiopacidade entre as resinas estudadas em todos os sistemas digitais e filme radiográfico. ALERT® e Difinite® foram estatisticamente equivalentes ao esmalte no sistema digital Sens-A-Ray® e no filme radiográfico. As demais resinas (Charisma®, FillMagic®, P60®, Prodigy®, Surefil® e Z250®) tiveram maior radiopacidade em comparação ao esmalte. Somente ALERT® teve radiopacidade similar à do esmalte em outros sistemas digitais (CDR®, Denoptix® e Digora ®). Nesses sistemas digitais, Charisma®, FillMagic®, P60®, Prodigy®, Surefil® e Z250® foram mais radiopacos do que o esmalte. Conclusão: todas as resinas, em todos os sistemas de avaliação, mostraram radiopacidade igual ou superior ao esmalte. Houve correlação estatística entre os sistemas CDR® e Sens-A-Ray® e entre Digora ® e DenOptix®, tendo o Sens-A-Ray® apresentado correlação também com o filme radiográfico. As médias de densidade equivalente em mm de alumínio em porcentagem para esmalte e dentina foram de 119,6% e 101,6%, respectivamente.

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.

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.

Diagnosis of invasive cervical resorption by using cone beam computed tomography: report of two cases

A radiographic interpretation is essential to the diagnosis of invasive cervical resorption (ICR) and the difficulty in distinguishing this lesion from internal root resorption has been highlighted in the literature. This paper reports the use of cone beam computed tomography (CBCT) in the diagnosis of ICR. The cases reports describe how CBCT can be used to make a differential diagnosis and also show that the use of this technology can provide relevant information on the location and nature of root resorption, which conventional radiographs cannot. As a result, the root canal treatment was not initially considered. The patients will be monitored and will undergo a scan after a short period of time to detect any small changes. It was observed that both cases benefited from CBCT in the diagnosis of ICR, because this imaging modality determined the real extent of resorption and possible points of communication with the periodontal space.

A interpretação radiográfica é essencial para o diagnóstico da reabsorção cervical invasiva (RCI) e a dificuldade em distingui-la da reabsorção radicular interna tem sido destacada na literatura. Este trabalho relata o uso da tomografia computadorizada de feixe cônico (TCFC) no diagnóstico da RCI. Os casos descrevem como a TCFC pode ser utilizada no diagnóstico diferencial e relatam também como esta tecnologia pode providenciar relevantes informações sobre a localização e natureza das reabsorções radiculares, limitadas pelas radiografias convencionais. Como resultado, o tratamento do canal radicular não foi inicialmente considerado. Os pacientes serão acompanhados e após curto período de tempo novos exames tomográficos serão realizados no intuito de detectar pequenas alterações. Observa-se que ambos os casos beneficiaram-se com o uso da TCFC no diagnóstico de RCI, pois esta modalidade de imagem determinou a real extensão da reabsorção e possíveis pontos de comunicação com o espaço periodontal.

Risk assessment of inferior alveolar neurovascular bundle by multidetector computed tomography in extractions of third molars.

PURPOSE: This study aimed to assess the reliability of multidetector computed tomography (MDCT) in determining the surgical risk of the inferior alveolar neurovascular bundle in extractions of third molars. METHODS: The sample comprised thirty-three individuals (63 third molars) who underwent preoperative evaluation by MDCT before extraction of impacted mandibular third molars. MDCT was used to determine the relationship between the roots of the third molars and the mandibular canal, and the course of the mandibular canal. Inferior alveolar nerve (IAN) exposure and the presence of hemorrhage were analyzed after removal of the teeth. IAN neurosensory deficit was recorded after 7 days. Clinical and MDCT findings were compared using Fisher's exact test (P < 0.05). RESULTS: There was a statistically significant association between IAN exposure and the tomographic relationship between the roots of third molars and the mandibular canal (P = 0.015). Conventionally, all cases of IAN neurosensory deficit and hemorrhage occurred when the roots of the third molar presented in an at-risk relationship with the mandibular canal, however, this association was not statistically significant (P > 0.05). A statistically significant association was found between the lingual course of the mandibular canal and IAN exposure (P = 0.03). CONCLUSIONS: MDCT is an effective tool for determination of the surgical risk to the inferior alveolar neurovascular bundle in extraction of mandibular third molars.