Influencia de la Morfología Externa de la Raíz de Primeros Premolares Superiores en la Sobreestimación del Espesor Radiográfico Radicular Durante la Preparación para Poste, Evaluados Mediante Tomografía Computarizada Cone Beam / Influence of the External Morphology of the Root of Upper First Premolars on the Overestimation of Radiographic Root Thickness During Post Preparation, Evaluated by Cone Beam Computed Tomography

La investigación tuvo como objetivo determinar la influencia de la morfología externa de la raíz de primeros premolares superiores en la existencia de sobreestimación radiográfica durante la preparación para poste. Con este fin se realizó un estudio transversal in vitro, donde 60 premolares superiores uniradiculares fueron instrumentadas con fresas Gates Glidden y Pesso de calibre 1, 2 y 3. Seguidamente se obtuvieron imágenes radiográficas digitales de cada pieza dentaria mediante un aparato posicionador a una distancia constante en sentido vestíbulo lingual, asimismo se realizaron imágenes tomográficas volumétricas de las muestras. En ambas técnicas imagenológicas se midió el espesor a mesial y distal de las piezas. La sobreestimación fue calculada mediante la diferencia de la medida tomográfica menos la radiográfica. Los resultados indicaron que en ambas paredes radiculares hubo diferencia significativa entre las medidas radiográficas y tomográficas (p<0,05), encontrándose en la pared distal diferencias altamente significativas (p<0,001); además se evidenció que la sobreestimación radiográfica fue mayor en la pared distal. El estudio concluyó que existe sobreestimación radiográfica en premolares superiores durante la preparación para poste de un 20,42 % en promedio, siendo la pared distal la estructura que presenta mayor sobreestimación.

SUMMARY: he investigation´s objective was to determine the influence of external morphology of the root of upper first premolars in the existence of radiographic overestimation during preparation for post. An in vitro cross-sectional study was carried out, where 60 single-rooted upper premolars were instrumented with burs. Gates Glidden and Pesso of caliber 1, 2 and 3, then, digital radiographic images of each dental piece were obtained by means of a positioning device at a constant distance in the buccolingual direction; volumetric tomographic images of the samples were also performed. In both imaging techniques, the mesial and distal thickness of the pieces was measured. The overestimation was calculated by the difference of the tomographic measurement minus the radiographic one. The results indicated that in both root walls there was a significant difference between the radiographic and tomographic measurements (p<0.05), with highly significant differences being found in the distal wall (p<0.001); In addition, it was evidenced that the radiographic overestimation was greater in the distal wall. The study concluded that there is radiographic overestimation in upper premolars during post preparation of 20.42% on average, with the distal wall being the structure that presents the greatest overestimation.

DICOM file format has better radiographic image quality than other file formats: an objective study

Abstract This study aimed to assess the influence of the file format on the image quality parameters (image noise, brightness, and uniformity) of periapical radiographs acquired with different digital systems. Radiographic images of an acrylic phantom were acquired with two digital systems - Digora Toto and Express, and exported into five different file formats - TIFF, BMP, DICOM, PNG, and JPEG. Image noise, image brightness (mean of gray values), and image uniformity (standard deviation of gray values) were evaluated in all images. A two-way analysis of variance with Tukey's test as a post-hoc test was used to compare the results, considering the file formats and radiographic systems as the studied factors. A significance level of 5% was adopted for all analyses. The DICOM image file format presented lower image noise, higher brightness (higher mean gray values), and greater image uniformity (p<0.001) than the other file formats, which did not differ from each other for both digital radiography systems (p>0.05). The Express system revealed lower image noise and greater image uniformity than the Digora Toto system regardless of the image file format (p<0.001). Moreover, the Express showed higher brightness than the Digora Toto for all image file formats (p<0.001), except for the DICOM image file format, which did not significantly differ between the digital radiography systems tested (p>0.05). The DICOM image file format showed lower image noise, higher brightness, and greater image uniformity than the other file formats (TIFF, BMP, PNG, and JPEG) in both digital radiography systems tested.

Resumo Este estudo teve como objetivo avaliar a influência do formato do arquivo nos parâmetros de qualidade de imagem (ruído de imagem, brilho e uniformidade) de radiografias periapicais adquiridas com diferentes sistemas digitais. As imagens radiográficas de um fantoma de acrílico foram adquiridas com dois sistemas digitais - Digora Toto e Express, e exportadas em cinco formatos de arquivo diferentes - TIFF, BMP, DICOM, PNG e JPEG. O ruído da imagem, o brilho da imagem (média dos valores de cinza) e a uniformidade da imagem (desvio padrão dos valores de cinza) foram avaliados em todas as imagens. A análise de variância (ANOVA) bidirecional com o teste post-hoc de Tukey foi aplicada para comparar os resultados, considerando os formatos de arquivo e os sistemas radiográficos como os fatores estudados. Um nível de significância de 5% foi adotado para todas as análises. O formato de arquivo de imagem DICOM apresentou menor ruído de imagem, maior brilho (maiores valores médios de cinza) e maior uniformidade de imagem (p<0,001) do que os outros formatos de arquivo, que não diferiram entre si para ambos os sistemas de radiografia digital (p>0,05). O sistema Express apresentou menor ruído de imagem e maior uniformidade de imagem que o sistema Digora Toto, independentemente do formato do arquivo de imagem (p<0,001). Além disso, o Express mostrou maior brilho do que o Digora Toto para todos os formatos de arquivo de imagem (p<0,001), exceto para o formato de arquivo de imagem DICOM, que não diferiu significativamente entre os sistemas de radiografia digital testados (p>0,05). O formato de arquivo de imagem DICOM mostrou menor ruído de imagem, maior brilho e maior uniformidade de imagem do que os outros formatos de arquivo (TIFF, BMP, PNG e JPEG) em ambos os sistemas de radiografia digital testados.

Could the radiographic image quality be affected by the excessive use of the photostimulable phosphor plate?

Abstract The study aimed to assess the influence of excessive use of a photostimulable phosphor plate (PSP) on the density, image noise, and contrast of radiographs. For that, radiographs of an acrylic block were acquired with a PSP of the Express intraoral system to assess the density and image noise. Initially, five images were obtained and exported (first group). After 400 exposures to X-rays and scannings of PSP, other five images were obtained and exported (second group). The same procedure was done after 800 (third group), 1200 (fourth group), 1600 (fifth group), and 2000 acquisitions (sixth group), resulting in 30 images to be evaluated. The mean and standard deviation of the gray values were calculated for the images using the ImageJ software. For contrast analysis, radiographs of an aluminum step-wedge were acquired with a new PSP following the same acquisition intervals. The percentage of contrast variation was calculated. Another two unused PSP receptors were employed to evaluate the method's reproducibility. The comparison of the results among the acquisition groups was performed with one-way Analysis of Variance (α=0.05). Intraclass Correlation Coefficient (ICC) assessed the reproducibility of the receptors. Image noise did not differ among the groups (p>0.05). There was a slight increase in density after 400 acquisitions and a slight difference in contrast for all acquisition groups without a pattern of increase or decrease (p<0.05). ICC showed excellent reliability for the methods. Therefore, excessive PSP use slightly affected the radiograph's density and contrast.

Resumo Objetivou-se avaliar a influência do uso excessivo de uma placa de fósforo fotoestimulável (PSP) na densidade, ruído e contraste das radiografias. Foram adquiridas radiografias de um bloco de acrílico com uma PSP do sistema intraoral Express para avaliar a densidade e o ruído da imagem. Inicialmente, cinco imagens foram obtidas e exportadas (primeiro grupo). Após 400 exposições aos raios X e escaneamentos, outras cinco imagens foram obtidas e exportadas (segundo grupo). O mesmo procedimento foi feito após 800 (terceiro grupo), 1200 (quarto grupo), 1600 (quinto grupo) e 2000 aquisições (sexto grupo), resultando em 30 imagens a serem avaliadas. A média e o desvio padrão dos valores de cinza foram calculados para as imagens usando o software ImageJ. Para análise de contraste, foram adquiridas radiografias de uma escala de alumínio com uma nova PSP seguindo os mesmos intervalos de aquisição. A porcentagem de variação do contraste foi calculada. Outras duas PSP sem uso prévio foram utilizadas para avaliar a reprodutibilidade dos métodos. A comparação dos resultados entre os grupos de aquisição foi realizada pela Análise de Variância one-way (α=0,05). O Coeficiente de Correlação Intraclasse (ICC) avaliou a reprodutibilidade dos receptores. O ruído da imagem não diferiu entre os grupos (p>0,05). Houve um leve aumento na densidade após 400 aquisições e uma pequena diferença no contraste para todos os grupos de aquisição sem padrão de aumento ou diminuição (p<0,05). O ICC mostrou excelente confiabilidade para os métodos. Portanto, o uso excessivo da PSP afetou levemente a densidade e o contraste radiográfico.

Relación entre el diagnóstico histopatológico de sacos foliculares de terceros molares y la medida radiográfca estandarizada en radiografía panorámica digital / Relationship between histopathologic diagnosis of third molar follicular sacs and standardized radiographic measurement on digital panoramic radiography

Objetivo: establecer la relación entre el diagnóstico histopatológico de sacos foliculares de terceros molares y la medida radiográfca estandarizada en radiografía panorámica digital. Métodos: se llevó a cabo un estudio descriptivo en el que se incluyeron 28 sacos foliculares de terceros molares. Dos observadores midieron la radiolucidez pericoronal en radiografías panorámicas digitales usando un método estandarizado y se calculó el índice de correlación intraclase. Se estableció un diagnóstico radiográfco según la medida del saco, con <2.5 mm como el límite para sacos foliculares normales. Dicho diagnóstico fue comparado con el respectivo diagnóstico histopatológico. Se calculó sensibilidad y especifcidad; se aplicó la prueba de chi-cuadrado, exacta de Fisher y, fnalmente, el índice Kappa. Resultados: se obtuvo un alto grado de acuerdo entre los observadores. La prueba radiográfca tuvo una baja sensibilidad (0.27) y especifcidad (0.6) y no se encontró diferencia estadísticamente signifcativa entre estos. Conclusiones: la ausencia de hallazgos radiográfcos no implica ausencia de enfermedad. Además, no se puede establecer relación entre la presencia de quistes dentígeros y radiolucidez ≥ 2.5 mm en radiografía panorámica digital.

Objective: To establish the relationship between the histopathological diagnosis of follicular sacs of third molars and the standardized radiographic measurement in digital panoramic radiography. Methods: This was a descriptive study in which 28 follicular sacs of third molars were included. In digital panoramic radiographs two observers measured the pericoronal radiolucency using a standardized method and the intraclass correlation index was calculated. A radiographic diagnosis was established according to the size of the sac, with <2.5mm being the limit for normal follicular sacs. This diagnosis was compared with the respective histopathological diagnosis. Sensitivity and specifcity were calculated; the chi-square test, Fisher's exact test and fnally the Kappa index were applied. Results: A high degree of agreement was obtained among the observers. The radiographic test had a low sensitivity (0.27) and specifcity (0.6) and no statistically signifcant diference was found between these. Conclusions: The absence of radiographic fndings does not imply absence of disease, furthermore, no relationship can be established between the presence of dentigerous cysts and radiolucency ≥ 2.5 mm in digital panoramic radiography.

How is the use of digital dental radiology in a developing country? An overview of Brazil / ¿Cómo es el uso de la radiología dental digital en un país en vías de desarrollo? Una visión general de Brasil

Abstract The aim of this study was to assess the use of digital dental radiology in Brazil, by focusing on the use of image receptors, imaging exams and digital image enhancement tools, also assessing the methods of professional image transfer. Questionnaires were distributed in person on dental meetings and digitally via messaging (WhatsApp®) and mailings list. The sample of this cross-sectional study consisted of 478 questionnaires. Most participants were woman (n=315, 65.9%), with average age of 33.8±9.2 years. Descriptive and frequency analysis was performed. Chi-square and Fisher's exact tests were used (α=0.05). Most dentists worked at shared dental clinics (34.7%) and use digital image receptors (51.1%), but a representative percentage (48.9%) still exclusively use radiographic films. Photostimulable phosphor plate is the most used digital image receptor. Among extraoral exams, panoramic radiography (PAN) is the most used. Regarding dental specialties, oral radiologists and oral and maxillofacial surgeons mostly use cone-beam computed tomography (p<0.001). Most dentists who use digital systems make use of digital image enhancement tools (87.8%), mainly contrast, zoom, brightness and measurements. The most common method of professional image transfer (professional-professional and professional-patiens) is by email, with few dentists using online app and social media (26%). Therefore, while most Brazilian dentists use digital imaging systems, a significant percentage still exclusively use radiographic films. The most extraoral imaging exams used is PAN. Regarding image enhancement tools, brightness and contrast adjustments, zoom and measurements are the most applied. Finally, dentists generally use email for professional image transfer.

Resumen El objetivo de este estudio fue evaluar uso de la radiología dental digital en Brasil, centrándose en uso de receptores de imagen, exámenes de imágenes y herramientas de mejora de imagen digital, evaluando también los métodos de transferencia de imagen profesional. Cuestionarios se distribuyeron de forma presencial en reuniones odontológicas y de forma digital a través de mensajería (WhatsApp®) y lista de correo. Muestra de este estudio transversal estuvo compuesta por 478 cuestionarios. Mayoría de los participantes eran mujeres (n=315, 65,9%), con edad promedio de 33,8±9,2 años. Se realizó un análisis descriptivo y de frecuencias. Se utilizaron las pruebas Chi-cuadrado y exacta de Fisher (α=0,05). La mayoría de los odontólogos trabajaban en clínicas dentales compartidas (34,7%) y utilizan receptores de imágenes digitales (51,1%), pero un porcentaje representativo (48,9%) todavía utiliza exclusivamente películas radiográficas. Placa de fósforo fotoestimulable es el receptor de imagen digital más utilizado. Entre los exámenes extraorales, la radiografía panorámica (PAN) es la más utilizada. En cuanto a las especialidades odontológicas, los radiólogos orales y los cirujanos orales y maxilofaciales utilizan mayoritariamente la tomografía computarizada de haz cónico (p<0,001). Mayoría de los odontólogos que utilizan sistemas digitales utilizan herramientas de mejora de imagen digital (87,8%), principalmente contraste, zoom, brillo y medidas. Método más común de transferencia de imágenes profesionales (profesional-profesional y profesional-pacientes) es por correo electrónico, con pocos dentistas que utilizan aplicaciones en línea y redes sociales (26%). Por lo tanto, mientras que la mayoría de dentistas brasileños utilizan sistemas de imágenes digitales, un porcentaje significativo aún utiliza exclusivamente películas radiográficas. Examen de imagen extraoral más utilizado es el PAN. En cuanto a las herramientas de mejora de imagen, los ajustes de brillo y contraste, el zoom y las medidas son las más aplicadas. Finalmente, los dentistas generalmente usan el correo electrónico para la transferencia de imágenes profesionales.

Comparación entre trazados cefalométricos manual y digital en radiografías laterales del cráneo / Comparison between Manual and Digital Cephalometric Tracing in Side Radiographies of the Skull

Resumen Objetivo: Evaluar la diferencia del trazado cefalométrico manual con el digital en radiografías laterales de cráneo. Materiales y métodos: Inicialmente se realizó un piloto para calibrar al investigador principal, en donde se analizaron 10 radiografías pertenecientes a cinco pacientes del Servicio de Radiología del Centro Odontológico de nuestra institución para evaluar la concordancia entre los dos evaluadores y establecer el tamaño de la muestra. Finalmente, se analizaron 78 radiografías cefalométricas de 39 pacientes, en las que se realizó el trazado cefalométrico de Steiner manual y digital. Esas radiografías se analizaron en una escala 1:1 y posteriormente se evaluó la diferencia de las mediciones mediante el análisis univariado, se determinó en mediana e intervalo intercuartil por separado. En el análisis bivariado, se aplicó la prueba de signo de rangos de Wilcoxon y muestras pareadas para determinar la diferencia de las mediciones cefalométricas de Steiner entre el tipo del análisis cefalométrico. El nivel de significancia se fijó en p < 0,05 y confiabilidad al 95%, respectivamente. Resultados: No hubo diferencia significativa en la mayoría de las mediciones hechas de manera manual y digital, siendo el ángulo interincisal la única medición angular en la cual hubo diferencia significativa al obtener un resultado de p = 0,002. Mientras tanto, en las mediciones lineales, la única medición en la que hubo diferencia significativa fue en el segmento incisivo inferior - NB con p = 0,005. Conclusión: No se encuentran diferencias significativas entre el trazado cefalométrico manual y el digital. No obstante, es importante tener en cuenta que la muestra o población evaluada es reducida para definir conclusiones.

Abstract Objective: To evaluate the difference of the manual cephalometric tracing with the digital tracing on lateral cranial radiographs. Materials and Methods: Initially, a pilot study was carried out to calibrate the principal investigator, where 10 radiographs belonging to 5 patients of the Radiology Service of the Dental Center, were analyzed to evaluate the intraclass concordance between the two evaluators. To establish the size of the sample, finally, 78 cephalometric radiographs of 39 patients were analyzed, in which the manual and digital Steiner cephalometric tracing was performed. These radiographs were analyzed on a 1: 1 scale and then the difference of the measurements was evaluated using the univariate analysis, which was determined in the median and interquartile range, separately. In the bivariate analysis, the Wilcoxon rank sign test and paired samples were applied to determine the difference of Steiner's cephalometric measurements between the cephalometric analysis type. The level of significance was set at p < 0.05 and 95% reliability, respectively. Results: There was no significant difference in most of the measurements made manually and digitally. The interincisal angle the only angular measurement in which there was a significant difference when obtaining a result of p = 0.002, while, in the linear measurements, the only measurement in which there was significant difference was in the lower incisor segment - NB with p = 0.005. Conclusion: There is no significant difference between manual and digital cephalometric tracing, nevertheless it is important to keep in mind that the simple or population evaluated is reduced to define conclusions.

Radiopacidad de Cementos de Resina Compuesta Evaluados con Técnica Radiográfica Digital / "Radiopacity of Resin Cements Evaluated with Digital Radiographic Technique"

RESUMEN: Objetivo: comparar la radiopacidad de distintos cementos de resina y corroborar si cumplen con los requisitos de normativas ISO. Material y método: Se prepararon muestras de 1 mm de grosor de los cementos de resina: RelyX U200 (3M ESPE), Calibra (Dentsply Sirona), Calibra Universal (Dentsply Sirona) y Bifix SE (VOCO). Las muestras fueron radiografiadas junto a una cuña de aluminio escalonada. Las imágenes fueron analizadas para determinar el valor en escala de grises y su respectivo valor en mm de Al. Los datos fueron analizados para comparar la radiopacidad de los materiales entre sí y con los requisitos establecidos por normas ISO. Resultados: La radiopacidad equivalente en mm de Al en orden descendiente fue de 2,84 ± 0,18 para Calibra, 2,37 ± 0,15 para Bifix SE, 2,26 ± 0,14 para Calibra Universal y de 1,67 ± 0,07 para RelyX U200. Estos valores son todos mayores al mismo grosor de aluminio exigido por la norma ISO 4049. Se establecieron diferencias estadísticamente significativas entre los cementos. Conclusiones: Se determinó que existen diferencias en la radiopacidad entre los cementos de resina compuesta estudiados. Sin embargo, todos los cementos evaluados cumplen con la norma ISO-4049 de radiopacidad.

ABSTRACT: Objective: Compare the radiopacity of different resin cements and verify their compliance with the requirements of ISO regulations. Material and method: Samples -10 mm in diameter and 1 mm thickness- of the resin cements RelyX U200 (3M ESPE), Calibra (Dentsply Sirona), Universal Calibra (Dentsply Sirona) and Bifix SE (VOCO) were prepared. Radiographies of the samples with a stepped aluminum wedge were obtained. For each sample, the grayscale and mm of Al values were calculated. The data were analyzed to compare the radiopacity of the materials and to contrast them with the requirements established by ISO standards. Results: The equivalent radiopacity in mm of Al in descending order was 2.84 ± 0.18 for Calibra, 2.37 ± 0.15 for Bifix SE, 2.26 ± 0.14 for Calibra Universal and 1.67 ± 0.07 for RelyX U200. These values exceed the value required by ISO 4049 standard. Statistically significant differences were established between the cements. Conclusion: There are differences in the radiopacity of the resin cements studied. However, all the cements complied with ISO 4049 radiopacity standards.

Método químico simplificado de desmineralización del esmalte dental humano / Simplified chemical method of demineralization in human dental enamel

Introducción: Se requieren métodos experimentales abreviados para simular las lesiones de desmineralización temprana de forma controlada y reproducible. Objetivo: Realizar una evaluación in vitro de un método simple de desmineralización incipiente del esmalte. Métodos: Estudio experimental aleatorizado con doble diseño factorial de réplicas. Se seleccionaron 12 terceros molares de sujetos humanos saludables para su desmineralización en solución de ácido láctico racémico. Las muestras se distribuyeron aleatoriamente: Grupo 1 (G1) (n= 6) ácido láctico a pH 2,4 y Grupo 2 (G2) (n= 6) ácido láctico a pH 5,4. A continuación, cada grupo se subdividió (n = 2) para evaluar el efecto de las soluciones a tres tiempos de exposición (7, 15 y 30 días) a 37 °C. La evaluación se llevó a cabo con estereomicroscopios, equipo de radiografía digital con un software de análisis digital de imágenes y microscopía de polarización. Se formuló una integración de los índices de respuesta y se realizó un ANOVA. Resultados: Los hallazgos visuales, radiográficos e histológicos mostraron que en el G1 en los tiempos 1 a 3, la desmineralización se caracterizó por una gran pérdida de la integridad del esmalte (80 por ciento a 100 por ciento). Visualmente, el G2 a los 7 días mostró opacidad y pérdida de brillo (16 por ciento) con preservación de la estructura superficial del esmalte. Conclusiones: Se demuestra que el empleo de ácido láctico durante 7 días a pH 5,4 produce una lesión clínica, radiográfica e histológica similar a una lesión temprana del esmalte(AU)

Introduction: Abridged experimental methods are required to simulate early demineralizing lesions in a controlled and reproducible way. Objective: Perform an in vitro evaluation of a simple method of incipient enamel demineralization. Methods: Randomized experimental study with a double factorial replication design. Twelve third molars from healthy human subjects were selected for demineralization in a racemic lactic acid solution. Samples were then distributed randomly: Group 1 (G1) (n= 6) lactic acid at pH 2.4 and Group 2 (G2) (n= 6) lactic acid at pH 5.4. Each group was then subdivided (n = 2) to evaluate the effect of the solutions at three exposure times (7, 15 and 30 days) at 37°C. The evaluation used stereomicroscopes, a digital x-rays apparatus with software for the digital analysis of images, and polarization microscopy. An integration of the response indices was formulated and ANOVA was performed. Results: Visual, radiographic and histological findings showed that G1 at time 1 through 3 displayed demineralization characterized by extensive loss (80 percent to 100 percent) of enamel integrity. Visually, G2 at 7 days exhibited opacity and loss of brightness (16 percent), with preservation of the surface structure of the enamel. Conclusions: It was shown that employing lactic acid for 7 days at pH 5.4 develops a clinical, radiographic and histological injury similar to an early enamel lesion(AU)

Application of e-learning in dental radiology education at undergraduate level ­a systematic review / Aplicação do e-learning no ensino de radiologia dentária em nível de graduação - uma revisão sistemática

With the increase in internet technology as well as the electronic content the web-based learning has become the desirable medium in the field of education. In medical, dental and allied health science education, the conventional method involves the use of textbooks, lectures, and images. But trends suggest that a change is poised in this field. Objective: the systematic review aims to evaluate the literature of studies about the application of the e-Learning methods in radiology education at the undergraduate level in comparison to conventional teaching-learning methods. Material and Methods: prominent scientific databases were searched for literature related to the application of e-Learning in undergraduate radiology education. The search keywords used for the search were- E-learning, dental radiology, oral radiology, undergraduate. English language full text of eligible article was systematically reviewed. Results: seven full text articles were obtained after scrutiny of the available literature. Most of the research work was carried out in the past decade and dental schools in different parts of the world. Almost all the studies showed that e-learning was as either equally effective or more effective when compared to conventional teaching in dental radiology. Conclusion: e-learning could be a suitable alternative to conventional teaching-learning method with significant improvement in student attitude and knowledge however, the influence of e-learning in improving the practical or clinical skills of dental radiography is still debatable (AU)

Com o aumento da tecnologia da Internet, como também o conteúdo eletrônico da aprendizagem baseada na web, estes tornaram-se um meio desejável no campo da Educação. Em ciências médicas, odontológicas e afins, o método convencional envolve o uso de livros didáticos, palestras e imagens. Mas tendências sugerem que há uma mudança nesse campo. Objetivos: esta revisão sistemática visa avaliar literatura de estudos sobre a aplicação de métodos de e-Learning no ensino de radiologia no nível de graduação em comparação com os métodos convencional de ensino-aprendizagem. Material e Métodos: bases de dados científicas importantes foram pesquisadas sobre literatura relacionada à aplicação do e-Learning na graduação em radiologia. As palavraschave usadas para a pesquisa foram: E-learning, radiologia dentária, radiologia oral, graduação. O texto completo do artigo elegível em inglês foi sistematicamente revisado. Resultados: sete textos completos foram obtidos após análise minuciosa da literatura. A maior parte dos trabalhos de pesquisa foi realizada na década passada em escolas de odontologia em diferentes partes do mundo. Quase todos os estudos mostraram que o e-learning era igualmente eficaz ou mais eficaz quando comparado ao ensino convencional em radiologia dentária. Conclusão: o e-learning pode ser uma alternativa adequada ao ensino-aprendizagem convencional, com melhoria significativa nas atitudes e conhecimentos aluno. No entanto, a influência de e-learning para melhorar as habilidades práticas ou clínicas da radiolog ia dentária ainda é discutível(AU)

Addition of zirconium oxide to Biodentine increases radiopacity and does not alter its physicochemical and biological properties

Abstract Objectives: To evaluate the radiopacity of Biodentine (BD) and BD associated with 15% calcium tungstate (BDCaWO4) or zirconium oxide (BDZrO2), by using conventional and digital radiography systems, and their physicochemical and biological properties. Materials and Methods: Radiopacity was evaluated by taking radiographs of cement specimens (n=8) using occlusal film, photostimulable phosphor plates or digital sensors. Solubility, setting time, pH, cytocompatibility and osteogenic potential were also evaluated. Data were analyzed using one-way ANOVA and Tukey post-test or two-way ANOVA and Bonferroni post-test (α=0.05). Results: BD radiopacity was lower than 3 mm Al, while BD ZrO2 and BD CaWO4 radiopacity was higher than 3 mm Al in all radiography systems. The cements showed low solubility, except for BDCaWO4. All cements showed alkaline pH and setting time lower than 34 minutes. MTT and NR assays revealed that cements had greater or similar cytocompatibility in comparison with control. The ALP activity in all groups was similar or greater than the control. All cements induced greater production of mineralized nodules than control. Conclusions: Addition of 15% ZrO2 or CaWO4 was sufficient to increase the radiopacity of BD to values higher than 3 mm Al. BD associated with radiopacifiers showed suitable properties of setting time, pH and solubility, except for BDCaWO4, which showed the highest solubility. All cements had cytocompatibility and potential to induce mineralization in Saos-2 cells. The results showed that adding 15% ZrO2 increases the radiopacity of BD, allowing its radiography detection without altering its physicochemical and biological properties.

Comparison of Cone-Beam Computed Tomography and Intraoral Radiography in Detection of Recurrent Caries under Composite Restorations

Abstract Secondary caries is the most common cause of dental restoration failures. This study aimed to compare the diagnostic accuracy of conventional and digital intraoral radiography and cone beam computed tomography (CBCT) for detection of recurrent caries around composite restorations. mesio-occluso-distal (MOD) cavities were prepared using bur on 45 extracted sound human molar teeth. The teeth were divided into 3 groups. In the control group, cavities were restored with composite resin after etching and bonding (n=15). In Group 2, 500-μm thick wax was placed over the buccal, lingual and gingival walls and the cavities were restored with composite resin. Group 3 specimens were subjected to pH cycling and artificial caries were created on the buccal, lingual and gingival walls. The cavities were restored with composite. Conventional and digital photo-stimulable phosphor (PSP; Optime) radiographs and two CBCTs images (NewTom 3G and Cranex 3D) were obtained from them. Presence or absence of caries in the cavity walls was assessed on these images. Data were analyzed using Kappa statistic. The diagnostic accuracy of CBCT was significantly higher than that of digital and conventional intraoral radiography (p<0.05). The accuracy was 0.83, 0.78, 0.55 and 0.49 for CBCT Cranex 3D, CBCT NewTom 3G, conventional and digital intraoral radiography, respectively. CBCT has a higher diagnostic accuracy than digital and conventional intraoral radiography for detection of secondary caries around composite restorations.

Resumo A causa mais comum de falha das cáries dentais são as cáries secundárias. Este estudo objetivou comparar a acurácia diagnóstica da radiografia intraoral digital e convencional com a tomografia computadorizada de feixe cônico (TCFC) para a detecção de cáries recorrentes em torno restaurações com compósitos. Cavidades mésio-oclusais-distais (MOD) foram produzidas com broca em 45 molares hígidos humanos extraídos. Os dentes foram dividdos em 3 grupos. No grupo controle, as cavidades foram restauradas com compósito após condicionamento e colagem (n=15). No Grupo 2, foi aplicada uma camada de cera de 500 µm de espessura sobre as paredes bucais, linguais e gengivais; as cavidades foram então restauradas com resina composta. No Grupos 3, as amostras foram submetidas a ciclagem de pH e criação artificial de cáries sobre as paredes bucais, linguais e gengivais; as cavidades foram então restauradas com resina composta. Radiografias convencional e digital com fósforo foto-estimulável (PSP, Optima) e duas imagens em TCFC (NewTom 3G e Granex 3D) foram obtidas de cada amostra. A presença ou não de cáries foi avaliada nestas imagens. Os dados foram analisados por estatística Kappa. A acurácia diagnóstica da TCFC foi significantemente (p<0,05) maior que na radiografia intraoral convencional e digital. A acurácia foi de 0,83, 0,78, 0,55 e 0,49, respectivamente para TCFC Cranex 3D, TCFC NewTom 3G, a radiografia intraoral convencional e digital. A TCFC tem maior acurácia diagnóstica que a radiografia intraoral convencional e digital para detecção de cáries secundárias em torno de restaurações com compósito.

Comparison of digital models generated from three-dimensional optical scanner and cone beam computed tomography

PURPOSE: The objective of this study was to compare the accuracy of digital models from 3 dimentional (3D) optical scanner and cone beam computed tomography (CBCT). MATERIALS AND METHODS: We obtained digital models from 11 pairs of stone casts using a 3D optical scanner and a CBCT, and compared the accuracy of the models. RESULTS: The error range of average positive distance was 0.059 - 0.117 mm and negative distance was 0.066 - 0.146 mm. Statistically (P < 0.05), average positive distance was larger than 70 µm and shorter than 100 µm, and that of negative distance was larger than 100 µm and shorter than 120 µm. CONCLUSION: We concluded that the accuracy of digital models generated from CBCT is not appropriate to make final prostheses. However, it may be acceptable for provisional restorations and orthodontic diagnoses with respect to the accuracy of the digitalization.

The effects of noise reduction, sharpening, enhancement, and image magnification on diagnostic accuracy of a photostimulable phosphor system in the detection of non-cavitated approximal dental caries

PURPOSE: Contrast, sharpness, enhancement, and density can be changed in digital systems. The important question is to what extent the changes in these variables affect the accuracy of caries detection. MATERIALS AND METHODS: Forty eight extracted human posterior teeth with healthy or proximal caries surfaces were imaged using a photostimulable phosphor (PSP) sensor. All original images were processed using a six-step method: (1) applying "Sharpening 2" and "Noise Reduction" processing options to the original images; (2) applying the "Magnification 1:3" option to the image obtained in the first step; (3) enhancing the original images by using the "Diagonal/" option; (4) reviewing the changes brought about by the third step of image processing and then, applying "Magnification 1:3"; (5) applying "Sharpening UM" to the original images; and (6) analyzing the changes brought about by the fifth step of image processing, and finally, applying "Magnification 1:3." Three observers evaluated the images. The tooth sections were evaluated histologically as the gold standard. The diagnostic accuracy of the observers was compared using a chi-squared test. RESULTS: The accuracy levels irrespective of the image processing method ranged from weak (18.8%) to intermediate (54.2%), but the highest accuracy was achieved at the sixth image processing step. The overall diagnostic accuracy level showed a statistically significant difference (p=0.0001). CONCLUSION: This study shows that the application of "Sharpening UM" along with the "Magnification 1:3" processing option improved the diagnostic accuracy and the observer agreement more effectively than the other processing procedures.

Accuracy of digital periapical radiography and cone-beam computed tomography in detecting external root resorption

PURPOSE: The purpose of this study was to evaluate and compare the efficacy of cone-beam computed tomography (CBCT) and digital intraoral radiography in diagnosing simulated small external root resorption cavities. MATERIALS AND METHODS: Cavities were drilled in 159 roots using a small spherical bur at different root levels and on all surfaces. The teeth were imaged both with intraoral digital radiography using image plates and with CBCT. Two sets of intraoral images were acquired per tooth: orthogonal (PA) which was the conventional periapical radiograph and mesioangulated (SET). Four readers were asked to rate their confidence level in detecting and locating the lesions. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of each modality in detecting the presence of lesions, the affected surface, and the affected level. Analysis of variation was used to compare the results and kappa analysis was used to evaluate interobserver agreement. RESULTS: A significant difference in the area under the ROC curves was found among the three modalities (P=0.0002), with CBCT (0.81) having a significantly higher value than PA (0.71) or SET (0.71). PA was slightly more accurate than SET, but the difference was not statistically significant. CBCT was also superior in locating the affected surface and level. CONCLUSION: CBCT has already proven its superiority in detecting multiple dental conditions, and this study shows it to likewise be superior in detecting and locating incipient external root resorption.

Prevalence of Candida spp. during radiographic examination in Diabetes mellitus patients / Prevalência de Candida spp. durante o exame radiográfico em pacientes diabéticos

Introdução: Relata-se que indivíduos diabéticos são mais susceptíveis a infecções por Candida que indivíduos saudáveis, especialmente se doença periodontal estiver associada. Objetivo: Este estudo propôs avaliar a prevalência de colonização por Candida spp. durante o exame radiográfico em pacientes diabéticos e não diabéticos. Material e Método: Vinte e seis pacientes com Diabetes mellitus do tipo 2 e 20 pacientes sem Diabetes mellitus, apresentando periodontite crônica e Candida spp. na saliva, foram avaliados. Durante o exame radiográfico, amostras de saliva foram coletas: da mucosa oral, do filme radiográfico periapical convencional, sensor radiográfico digital (CDR) e bloco de mordida do posicionador de filmes. Unidades formadoras de colônia (cfu/mL) e identificação das leveduras do gênero Candida foram avaliadas. Resultado: A mucosa oral de ambos os grupos mostrou maior colonização por Candida spp. quando comparada com outras superfícies coletadas (p < 0.05). Nos pacientes diabéticos, a mucosa da região esquerda superior mostrou níveis mais altos de colonização. Nos pacientes não diabéticos, a região de molar superior direito mostrou o nível mais alto de colonização durante o exame no posicionador, no sensor e no lado do filme periapical que não fica voltado para a radiação X. Os níveis de Candida spp. na saliva foram similares entre diabéticos (média = 3.0 × 10(6)) e não diabéticos (média = 3.8 × 10(6)). Conclusão: Nenhuma diferença na colonização por Candida spp. (cfu/mL) em pacientes diabéticos e não diabéticos foi observada nas cinco superfícies coletadas e nas regiões radiográficas simuladas. Candida albicans foi a espécie prevalente de Candida spp. encontrada em todas as amostras.

Introduction: It is suggested that individuals with diabetes are more susceptible to Candida infections than healthy people, especially if periodontal infection is associated. Objective: This study evaluated the prevalence of colonization by Candida spp. during radiographic examination in diabetic and non-diabetic patients. Material and Methods: Twenty-six patients with type 2 diabetes mellitus and 20 patients without diabetes mellitus, presenting chronic periodontitis and presence of Candida spp. in saliva were evaluated. During radiographic examination, samples of saliva were collected from: oral mucosa, conventional radiographic periapical film, digital x-ray sensor (CDR), and bite block of the receptor-positioning device. Colony forming units (cfu/mL) and identification of Candida yeasts were assessed. Result: Oral mucosa from both groups showed the highest colonization with Candida spp. if compared with others surfaces collected (p < 0.05). In diabetic patients, the mucosa of the upper left regions showed higher levels of colonization. In non-diabetic patients, the upper right molar region showed the highest level of colonization during the examination of the receptor-positioning device, the sensor and the non-sensitive film. Candida spp. levels in saliva were similar between diabetics (mean = 3.0 × 10(6)) and non-diabetics (mean = 3.8 × 10(6)). Conclusion: No difference in Candida spp. colonization (cfu/mL) in diabetics and non-diabetic patients was observed for the five collected surfaces and the simulated radiographic region. Candida albicans was the prevalent species of Candida spp. found on all the samples.

Radiopacity of restorative composites by conventional radiograph and digital images with different resolutions

PURPOSE: This study was performed to evaluate and compare the radiopacity of dentin, enamel, and 8 restorative composites on conventional radiograph and digital images with different resolutions. MATERIALS AND METHODS: Specimens were fabricated from 8 materials and human molars were longitudinally sectioned 1.0 mm thick to include both enamel and dentin. The specimens and tooth sections were imaged by conventional radiograph using #4 sized intraoral film and digital images were taken in high speed and high resolution modes using a phosphor storage plate. Densitometric evaluation of the enamel, dentin, restorative materials, a lead sheet, and an aluminum step wedge was performed on the radiographic images. For the evaluation, the Al equivalent (mm) for each material was calculated. The data were analyzed using one-way ANOVA and Tukey's test (p<0.05), considering the material factor and then the radiographic method factor, individually. RESULTS: The high speed mode allowed the highest radiopacity, while the high resolution mode generated the lowest values. Furthermore, the high resolution mode was the most efficient method for radiographic differentiation between restorative composites and dentin. The conventional radiograph was the most effective in enabling differentiation between enamel and composites. The high speed mode was the least effective in enabling radiographic differentiation between the dental tissues and restorative composites. CONCLUSION: The high speed mode of digital imaging was not effective for differentiation between enamel and composites. This made it less effective than the high resolution mode and conventional radiographs. All of the composites evaluated showed radiopacity values that fit the ISO 4049 recommendations.

Influência das imagens radiográficas convencional e digital no diagnóstico e decisão de tratamento de cáries proximais / Influence of conventional and digital images on the diagnosis and treatment decisions of interproximal caries

Objetivo: Comparar imagens do sistema digital Digora Fmx®, com placa de fósforo azul, e filme radiográfico Insight®, no diagnóstico de cáries proximais incipientes em esmalte e a sua influência na decisão de tratamento. Método: Foram selecionadas radiografias e imagens digitais de 44 dentes humanos que foram avaliadas, em negatoscópio e monitor de computador sendo atribuídos escores, na presença de cáries e na decisão do tratamento. Para realizar esta avaliação foi selecionado um grupo de 14 alunos do último ano da graduação de odontologia da Faculdade de Odontologia de Pernambuco. A concordância no diagnóstico de cárie foi atestada pelo índice Kappa calculado pela relação entre a sensibilidade e a especificidade e comparada com o padrão ouro. O teste exato de Fisher (p menor que 0,05) foi utilizado para avaliar a influência do diagnóstico na decisão de tratamento. Resultados: Os resultados não mostraram diferenças estatisticamente significativas entre modos de apresentação das imagens quanto ao diagnóstico de cáries proximais em esmalte. Entretanto, as imagens apresentaram-se diferentes do padrão ouro. Na comparação das avaliações radiográficas com a decisão de tratamento observou-se que a conduta de restaurar depende do diagnóstico da extensão da cárie (p menor que 0,001) e não mostrou ter sido influenciada pelo sistema (p=1,000). Conclusão: O sistema digital Digora Fmx®, com a placa de fósforo azul, e o filme radiográfico Insight® demonstraram desempenhos semelhantes na detecção de cáries proximais incipientes; O comprometimento histológico da dentina pela cárie, acarretou no aumento da quantidade de faces corretamente diagnosticadas por meio das modalidades de apresentação das imagens. A decisão de restaurar foi coerente com o diagnóstico da extensão da cárie.

Objective: To compare digital images of the Digora digital system Fmx with blue phosphor plate and the radiographic film Insight, for the diagnosis of incipient interproximal caries in enamel, and their influence on the treatment decision of the lesions. Method: Conventional and digital radiographs of 44 human teeth were selected, and examined on light box and computer screen to attribute scores regarding the presence of caries and treatment decision. Fourteen undergraduate students from the last year of the School of Dentistry of Pernambuco, Brazil, were selected to perform the evaluation. The interexaminer agreement on caries diagnosis was attested by the kappa index, calculated by assessing sensitivity and specificity, and compared with the gold standard. Fisher's exact test (p<0.05) was used to evaluate the influence of diagnosis on treatment decision. Results: No statistically significant differences were found between the radiographic imaging modes regarding the diagnosis of interproximal caries in enamel. However, all images differed from the gold standard. Comparison between the radiographic evaluations and the treatment decision revealed that the choice for restoring the tooth relied on the diagnosis of caries extension (p<0.001), and was not influenced by the radiographic imaging mode (p=1.000). Conclusion: Digora Fmx digital system with blue phosphor plate and the radiographic film Insight showed similar performance for detection of incipient proximal caries. The histological involvement of dentin by caries increased the number of correctly diagnosed tooth surfaces by both radiographic imaging modes. The decision to restore the tooth was consistent with the diagnosis of caries extension.

Radiopacity of resin cements: in vitro study / Radiopacidade de cimentos resinosos: estudo in vitro

Objective: To evaluate the radiopacity of seven different resin cements, noting whether they are in accordance with the requirements of ANSI/ADA no. 27/1993 and ISO no. 4049/2000, comparing the conventional radiographic system with digital (phosphor plate). Methods: For each material, five samples were prepared that were irradiated and tested in both systems; the optical density of the cement and each step-wedge of the penetrometer were measured. From the resulting values, the equivalent for each mm of aluminum material was obtained.Results: We found the lowest values in AllCem-FGM, Joinville, Brazil (2.06 and 4.63 Eq mmAl), and the highest values in the Fill Magic Dual Cement-Vigodent, Rio de Janeiro, Brazil (4.03 and 9.20 mmAl eq). Through the F-test (ANOVA) with two factors, a significant difference was confirmed between the two system types (p <0.05) and between cements (p <0.05). On the other hand, the interaction between type of system and cement was not significant (p> 0.05). Through the Tukey test, a significant difference was found between the cement Fill Magic Dual Cement (Vigodent, Rio de Janeiro, Brazil) and each of the other cements: AllCem (FGM, Joinville, Brazil), Cement Post (Angelus, Londrina, Brazil), RelyX Unicem (3M ESPE, St. Paul, MN, USA), SET (SDI, Victoria, Australia), regardless of the system. Conclusion: All cements fell within the standards, where the AllCem (FGM, Joinville, Brazil) had the lowest value of radiopacity and Fill Magic Dual Cement (Vigodent, Rio de Janeiro, Brazil) the highest, irrespective of the type of system.

Objetivo: Avaliar a radiopacidade de sete cimentos resinosos diferentes, observando se os mesmos encontram-se de acordo com as normas da ANSI / ADA n. 27/1993 e ISO n. 4049/2000, comparando-se o sistema radiográfico convencional com o digital (placa de fósforo). Métodos: Para cada material confeccionaram-se cinco amostras, que foram irradiadas, e analisadas em ambos os sistemas, mediram-se a densidade óptica dos cimentos e de cada degrau do penetrômetro. A partir dos valores encontrados obteve-se o equivalente em milímetros de alumínio para cada material. Resultados: Constatou-se menores valores no AllCem-FGM, Joinville, Brasil (2,06 e 4,63 Eq mmAl), e maiores no Fill Magic Dual Cement-Vigodent, Rio de Janeiro, Brasil (4,03 e 9,20 Eq mmAl) . Através do teste F (ANOVA) com dois fatores se comprovou diferença significativa entre os dois tipos de sistema (p < 0,05) e entre os cimentos (p < 0,05). Por outro lado, a interação do tipo de sistema e cimento não se mostrou significativa (p > 0,05). Através do teste de Tukey se evidenciou diferença significativa entre o cimento Fill Magic Dual Cement (Vigodent, Rio de Janeiro, Brasil) com cada um dos cimentos: AllCem (FGM, Joinville, Brasil), Cement Post (Angelus, Londrina, Brasil), RelyX Unicem (3M ESPE, Saint Paul, EUA), seT (SDI, Victória, Austrália), independente do tipo de sistema.Conclusão: Todos os cimentos estavam dentro das normas, onde o AllCem (FGM, Joinville, Brasil) apresentou menores valores de radiopacidade e o Fill Magic Dual Cement (Vigodent, Rio de Janeiro, Brasil) os maiores, independente do tipo de sistema.

Avaliação da influência da velocidade de perfuração na reabsorção óssea ao redor de implantes osseointegrados instalados por meio de cirurgia guiada sem retalho: estudo clínico, radiográfico e histológico / Effect of drilling speed on bone remodelling around implants installed with flapless guided surgery. Clinical radiographic and histologic study

O objetivo deste estudo realizado em humanos e animais foi avaliar clínica, radiográfica e histologicamente a influência da velocidade de perfuração no tecido ósseo peri-implantar em implantes instalados com cirurgia guiada sem retalho. No estudo em animais, 30 implantes foram instalados em ambas as tíbias de 15 coelhos com diferentes velocidades de perfuração (Controle ­ 1500 r.p.m e Teste ­ 50 r.p.m.) para avaliação histológica de BIC e BA nos períodos de 4, 8 e 12 semanas. Na segunda parte do estudo, foram realizadas 30 perfurações ósseas nas tíbias de 15 coelhos. A distribuição dos grupos foi de acordo com a velocidade de perfuração utilizada na primeira parte do estudo para avaliação histológica nos períodos de 0, 7 e 14 dias. No estudo em humanos, 64 implantes foram instalados com cirurgia guiada sem retalho em 16 mandíbulas edêntulas. Em cada paciente foram instalados 2 implantes utilizando as duas velocidades de perfuração do estudo em coelhos. A avaliação clínica e radiográfica foi realizada durante 1, 3, 6 e 12 meses. No estudo em coelhos, os 2 grupos mostraram regeneração óssea progressiva na região do defeito sem mostrar diferença estatística. Na avaliação do contato osso-implante e área óssea entre as espiras, não foram observadas diferenças significantes entre os grupos. No estudo clínico foi observado um índice de sucesso de 90% após um ano em função. O nível ósseo médio durante o período experimental foi de 0,83 mm. Treze em 16 próteses pré-fabricadas não apresentaram adaptação confirmada por radiografias periapicais digitais. Três implantes de cada grupo foram perdidos durante o período de avaliação de 3 meses. Um dos implantes perdidos foi avaliado mediante histologia e apresentou necrose na região apical. Não foi observada diferença significante entre os grupos com relação ao IP, SS e à avaliação da estabilidade dos implantes. Na avaliação por subtração radiográfica foi observada diferença estatisticamente significante nos valores médios de tons de cinza relacionados ao ganho ósseo e na área média relacionada ao ganho e à perda óssea entre os grupos experimentais (p<0.05). Dentro das limitações deste estudo, podemos concluir que a velocidade de perfuração não influenciou o padrão de regeneração óssea na região do defeito e também não afetou o padrão de osseointegração em implantes instalados em coelhos. Clinicamente, não foi observada a influência da velocidade de perfuração no nível ósseo. Entretanto, a velocidade de perfuração de 50 r.p.m. apresentou maior mineralização no tecido ósseo peri-implantar durante o período experimental

The aim of this study was to evaluate clinical, histologic and radiographically the effect of drilling speed on bone tissue around implants installed with flapless guided surgery. Thirty implants were installed in the tibial metaphysis of 15 rabbits with 2 different drilling speed (Control ­ 1500 r.p.m and Test ­ 50 r.p.m.). BIC and BA were assessed during 4, 8 and 12 weeks after implant placement. Then, 30 bone defects were performed in the tibial metaphysis of 15 rabbits with the same drilling speed groups. The histologic evaluation was performed at 0, 7 and 14 days. In the clinical study, 64 implants were installed in 16 edentulous mandibles with flapless guided surgery. Two implants per patient were instaled wtih the same protocol and distribution of drilling speed groups of the animal study and they were clinical and radiographically evaluated during 1, 3, 6 and 12 months. In rabbits, both groups showed progressive bone repair around the defect without statistical differences. No differences between groups were showed in terms of bone implant-contact and bone area. The clinical evaluation showed 90% of implant survival during the experimental period. Mean bone level after 12 months of function was 0.83 mm. A radiographically misfit was observed in 13 of 16 patients between abutment and pre-fabricated prostheses. Three implants of both experimental groups were lost during 3 months evaluation. One implant was assessed histologically and showed apical necrotic bone. No statistical difference between groups were showed at PI, BoP and implant stability. Statistically difference (p<0.05) was showed between groups at mean gray level of bone gain and mean area of bone gain and bone loss evaluation. Within the limitations of this study, it can be concluded that the drilling speed do not have effect on bone repair and it did not present alterations on the osseointegration pattern. Clinically, it did not show influence at bone level around implants installed with flapless guided surgery. However, low drill speed induced increase of mineralizated periimplant bone tissue during the experimental study

The reduction methods of operator's radiation dose for portable dental X-ray machines

OBJECTIVES: This study was aimed to investigate the methods to reduce operator's radiation dose when taking intraoral radiographs with portable dental X-ray machines. MATERIALS AND METHODS: Two kinds of portable dental X-ray machines (DX3000, Dexcowin and Rextar, Posdion) were used. Operator's radiation dose was measured with an 1,800 cc ionization chamber (RadCal Corp.) at the hand level of X-ray tubehead and at the operator's chest and waist levels with and without the backscatter shield. The operator's radiation dose at the hand level was measured with and without lead gloves and with long and short cones. RESULTS: The backscatter shield reduced operator's radiation dose at the hand level of X-ray tubehead to 23 - 32%, the lead gloves to 26 - 31%, and long cone to 48 - 52%. And the backscatter shield reduced operator's radiation dose at the operator's chest and waist levels to 0.1 - 37%. CONCLUSIONS: When portable dental X-ray systems are used, it is recommended to select X-ray machine attached with a backscatter shield and a long cone and to wear the lead gloves.