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.

Human Identification by Comparative Analysis of Frontal Sinuses: Study on Computed Tomography

ABSTRACT: Generally, primary methods of identification as the fingerprint analysis, dental analysis or DNA examination are indicated for the establishment of the identity of a corpse. In situations with poor body conservation, such as in advanced stage of putrefaction or skeletonization, imaging exams like medical and dental computed tomography can assist in the process of identification. The frontal sinuses present anatomical characteristics that allow the establishment of the identity of an in dividual. In this case report we used the technique of three-dimensional construction of the frontal sinuses through the generation of solid figures representative of the sinus morphology. After the comparative analysis of the antemortem and postmortem tomography of the alleged victim, we could establish similarities in both the variations in size, shape, symmetry and contour of borders, and the presence and number of septa, allowing us to infer that the two images described belong to the same individual, thus establishing the identity of the corpse found.

RESUMEN: Generalmente, los métodos primarios de identificación como el análisis dactiloscópico, el análisis dental o el examen de ADN están indicados para el establecimiento de la identidad de un cadáver. En situaciones de mala conservación del cuerpo, como en etapa avanzada de putrefacción o esqueletización, los exámenes de imagen como la tomografía computarizada médica y dental pueden ayudar en el proceso de identificación. Los senos frontales presentan características anatómicas que permiten establecer la identidad de un individuo. En este reporte de caso utilizamos la técnica de construcción tridimensional de los senos frontales a través de la generación de figuras sólidas representativas de la morfología sinusal. Tras el análisis comparativo de la tomografía antemortem y postmortem de la presunta víctima, pudimos establecer similitudes tanto en las variaciones de tamaño, forma, simetría y contorno de márgenes, como en la presencia y número de septos, lo que nos permite inferir que las dos imágenes descritas pertenecen al mismo individuo, estableciéndose así la identidad del cadáver encontrado.

Interexaminer agreement between two dental specialties for the detection of bifid mandibular canal and accessory mental foramen in cone-beam computed tomography / Concordancia inter-examinador entre dos especialidades odontológicas para la detección del canal mandibular bífido y foramen mental accesorio en tomografía computarizada de haz cónico

Introduction: The aim of this study was to assess the agreement between oral and maxillofacial radiologists (OMFR) and oral and maxillofacial surgeons (OMFS) for the detection of bifid mandibular canal (BMC) and accessory mental foramen (AMF) using cone-beam computed tomography (CBCT). Material and Methods: This retrospective study involved 22 examiners (11 OMFR and 11 OMFS) who independently assessed 30 CBCT volumes from patients (n = 60 hemi-mandibles) under preoperative radiographic evaluation for implant placement. The examiners scored the presence of BMC and AMF in each hemimandible. The interexaminer agreements were assessed using Fleiss' kappa statistics. Results: For intra-examiner agreement, 40% of the sample was reevaluated. The interexaminer agreement between OMFR and OMFS was slight (0.12) for the detection of BMC and fair (0.24) for AMF. The agreement among OMFR for detection of BMC was fair (0.22), and it was slight among OMFS (0.15). The agreement among OMFR for detection of AMF was substantial (0.61), and among OMFS it was fair (0.22). Agreements between OMFR and OMFS were slight for BMC and fair for AMF, independently of the years of experience. Intraexaminer agreement ranged from 60% to 90% among OMFR and from 55% to 90% among OMFS. Conclusion: A slight and a fair agreement between OMFR and OMFS was found for the detection of BMC and AMF, respectively. In general, OMFR obtained higher agreement among themselves, mainly for detection of AMF.

Introducción: El objetivo de este estudio fue evaluar la con-cordancia entre los radiólogos orales y maxilofaciales (ROMF) y los cirujanos orales y maxilofaciales (COMF) para la detección del canal mandibular bífido (CMB) y el foramen mentoniano accesorio (FMA) mediante tomografía computarizada de haz cónico. CBCT). Material y Métodos: Este estudio retrospectivo involucró a 22 examinadores (11 ROMF y 11 COMF) que evaluaron de forma independiente 30 volúmenes CBCT de pacientes (n = 60 hemimandíbulas) bajo evaluación radiográfica preoperatoria para la colocación de implantes. Los examinadores puntu-aron la presencia de CMB y FMA en cada hemimandíbula. Los acuerdos entre examinadores se evaluaron utilizando las estadísticas kappa de Fleiss. Resultados: Por concordancia intraexaminador se reeva-luó el 40% de la muestra. El acuerdo entre examinadores entre ROMF y COMF fue ligero (0,12) para la detección de CMB y regular (0,24) para FMA. La concordancia entre ROMF para la detección de CMB fue regular (0,22) y leve entre COMF (0,15). El acuerdo entre ROMF para la detección de FMA fue sustancial (0,61), y entre COMF fue justo (0,22). Los acuerdos entre ROMF y COMF fueron leves para CMB y justos para FMA, independientemente de los años de experiencia. La concordancia entre examinadores varió del 60 % al 90 % entre ROMF y del 55 % al 90 % entre COMF. Conclusión: Se encontró un acuerdo leve y justo entre ROMF y COMF para la detección de CMB y FMA, respec-tivamente. En general, se obtuvo mayor acuerdo entre ROMF, principalmente para la detección de FMA.

Evaluation of the microstructure, chemical composition, and image quality of different PSP receptors

Abstract This study aimed to assess the microstructure, chemical composition, and image quality of different photostimulable phosphor plates (PSP). Four PSP systems, Express®, Digora®, VistaScan®, and Apixia,® were assessed. Five radiographs of a homogeneous acrylic phantom were obtained with the PSP of each system, to acquire a total of 20 images. The images were objectively evaluated for uniformity using mean grey and standard deviation (SD) of their grey values. PSP receptors were analyzed using scanning electron microscopy (SEM) to determine the thickness of the granule layer and the size of the granules. The chemical composition of the PSP receptors was analyzed using total reflection X-ray fluorescence (TXRF). VistaScan showed more uniform and higher density images than the other tested systems (p < 0.05), as well as the lowest SD of grey values (p < 0.05). Regarding the microstructure of the receptors, Digora and VistaScan had thicker granule layers than Express and Apixia, and VistaScan had smaller granules than Digora and Express (p < 0.05). Fourteen chemical elements were detected in the receptors, with barium being the element with the highest concentration in all PSP systems. The microstructure, chemical composition, and image quality varied among all four PSP receptors studied. VistaScan receptors showed the smallest variation in granule size, one of the thickest granule layers, and the most uniform and least noisy images.

Oral and Maxillofacial Radiology During the Coronavirus Disease 2019 Pandemic: Recommendations for a Safer Practice / Radiología oral y maxillofacial durante la pandemia por Coronavirus 2019: recomendaciones para una práctica más segura

Abstract The Coronavirus 2019 disease (COVID-19), was declared a pandemic by the World Health Organization on March 11, 2020, and registered the first case in Costa Rica on March 6, 2020, and 105 days later reported 2058 cases, with a wide age range (0-92 years). Its etiologic agent is the beta coronavirus SARS-CoV-2 with confirmed human- to-human transmission, mainly by the respiratory route. The presence of asymptomatic carriers of the virus and its transmission even without the manifestation of symptoms challenges health professionals worldwide. For this reason, assuming all patients who need dental care as possible carriers of the SARS-CoV-2 is mandatory and consequently, applying biosecurity measures with strict criteria. In the present literature review, we aim to recommend biosecurity measures to be applied during imaging examinations of dental patients due to the Coronavirus-2019 pandemic. We found that in the absence of treatment for COVID-19 disease and because of its high transmissibility, the most effective measures to prevent its spread are those allowing its containment. Therefore, the authors recommend: 1) acquiring imaging exams just in case of dental urgencies or emergencies, 2) prioritizing the use of extraoral exams, such as panoramic radiography or CBCT, under the principle of ALADAI and 3) the intraoral exams should be used just in case of a lack of extraoral imaging devices, or because of the need to solve diagnostic tasks in which they have a superior diagnostic value than those of the extraoral examinations.

Resumen La enfermedad Coronavirus 2019, fue declarada pandemia por la Organización Mundial de la Salud el 11 de marzo de 2020; el primer caso registrado en Costa Rica fue el 6 de marzo de 2020, y 105 días después reportó 2058 casos, con un amplio rango de edad (0-92 años). Su agente etiológico es el beta coronavirus SARS- CoV-2. La transmisión de humano a humano está bien confirmada principalmente por la vía respiratoria. La presencia de portadores asintomáticos del virus y su transmisión, incluso sin la manifestación de síntomas, desafía a los profesionales de la salud. Por esta razón, es obligatorio asumir todos los pacientes que necesitan atención dental como posibles portadores del SARS-CoV-2 y, en consecuencia, aplicar medidas de bioseguridad con criterios estrictos. En la presente revisión de la literatura, nuestro objetivo es recomendar las medidas de bioseguridad que se aplicarán durante los exámenes de imágenes de pacientes dentales debido a la pandemia de Coronavirus-2019. Encontramos que en ausencia de tratamiento para la enfermedad de COVID-19 y debido a su alta transmisibilidad, las medidas más efectivas para prevenir su propagación son aquellas que permitan su contención. Por lo tanto, se recomienda: 1) adquirir exámenes por imágenes solo en caso de urgencias o emergencias dentales, 2) priorizar el uso de exámenes extraorales, como la radiografía panorámica o CBCT, bajo el principio de ALADAIP y 3) se deben usar los exámenes intraorales solo en caso de falta de dispositivos de imágenes extraorales, o por la necesidad de resolver tareas de diagnóstico en las que tienen un valor de diagnóstico superior al de los exámenes extraorales.

Effect of homeopathy in the function and morphology of salivary parotid glands of irradiated rats / Efeito da homeopatia na função e morfologia das glândulas parótidas de ratos irradiados

Objective: To evaluate the radioprotective effect of a homeopathic solution in salivary function and parotid glands morphology of irradiated rats. Materials and Methods: The sample consisted of 150 rats randomly divided into 6 groups. The groups were named based on the substance administered: Control- saline solution; Irradiated Control- saline solution and 15 Gy of X radiation; Alcohol-hydroalcoholic solution dynamized at 15 CH; Irradiated Alcohol- hydroalcoholic solution dynamized at 15 CH and 15 Gy of X radiation; Homeopathy- 0.25 ml (1mL/kg) of the irradiated hydroalcoholic solution and dynamized at 15 CH; Irradiated homeopathy- homeopathic solution and 15 Gy of X radiation. Each group was subdivided into 5 different subgroups, based on the time point of euthanasia: 12 hours, 3, 10, 17, and 24 days. The medication was administered for 7 days before and 7 days after the radiation treatment. On the day of euthanasia, salivation was induced with pilocarpine and collected. The animals were then sacrificed and the parotid glands were removed. Results: Salivary function analysis showed that only group irradiated homeopathy euthanized on day 17 had a statistically significant difference when compared to other irradiated groups, presenting a higher salivation flow rate. The only group that showed a statistically significant difference in the number of acini over time was the irradiated alcohol group, which presented a tendency of reduction. Conclusion: The homeopathic solution presented a late radioprotective effect based on salivary function and morphological analysis of the parotid gland.

Objetivo: Avaliar o efeito radioprotetor de uma solução homeopática na função salivar e na morfologia das glândulas parótidas de ratos irradiados. Materiais e Métodos: A amostra foi composta por 150 ratos divididos aleatoriamente em 6 grupos. Os grupos foram nomeados com base na substância administrada: solução salina controle; Solução salina controle irradiada e 15 Gy de radiação X; Solução álcool-hidroalcoólica dinamizada a 15 CH; Solução hidroalcoólica de álcool irradiado dinamizada a 15 CH e 15 Gy de radiação X; Homeopatia - 0,25 ml (1mL / kg) da solução hidroalcoólica irradiada e dinamizada a 15 CH; Homeopatia irradiada - solução homeopática e 15 Gy de radiação X. Cada grupo foi subdividido em 5 subgrupos diferentes, com base no tempo da eutanásia: 12 horas, 3, 10, 17 e 24 dias. O medicamento foi administrado por 7 dias antes e 7 dias após o tratamento com radiação. No dia da eutanásia, a salivação foi induzida com pilocarpina e coletada. Os animais foram então sacrificados e as glândulas parótidas foram removidas. Resultados: A análise da função salivar mostrou que apenas a homeopatia irradiada por grupo sacrificada no dia 17 apresentou diferença estatisticamente significante quando comparada a outros grupos irradiados, apresentando maior taxa de fluxo de salivação. O único grupo que apresentou diferença estatisticamente significante no número de ácinos ao longo do tempo foi o grupo álcool irradiado, o qual apontou uma tendência de redução. Conclusão: A solução homeopática apresentou efeito radioprotetor tardio baseado na função salivar e na análise morfológica da glândula parótida.

Automatic exposure compensation and subjective image enhancement in the radiographic diagnosis of caries

Abstract This study aims to assess the influence of high-density material on the radiographic diagnosis of proximal caries in digital systems with automatic exposure compensation, and to evaluate the effect of subjective adjustment of brightness and contrast to undertake this diagnostic task. Twenty bitewing radiographs of forty posterior human teeth with non-cavitated carious lesions, confirmed by micro-CT, were obtained with two digital systems. A porcelain-fused-to-metal crown attached to a titanium implant was inserted into the exposed area, and all the radiographs were repeated. Five radiologists assessed the radiographs and diagnosed proximal carious lesions. Afterwards, the observers were asked to adjust image brightness and contrast, based on their subjective perception, and to reassess the images. Thirty percent of each experimental group was reassessed to test intraobserver reproducibility, totaling 208 images per observer. Intraobserver and interobserver agreements ranged from fair to substantial. Sensitivity, specificity, predictive values, and area under the ROC curve were calculated and compared for each radiographic system, using ANOVA (α = 0.05). Overall, presence of high-density material and adjustment of brightness and contrast did not significantly influence the radiographic diagnosis of proximal caries (p ≥ 0.05). Regarding Digora Optime, adjustment of brightness and contrast significantly increased (p < 0.05) the diagnostic accuracy of proximal carious lesions in the presence of high-density material. In conclusion, the presence of high-density material in the X-rayed region does not influence radiographic diagnosis of proximal caries. However, when it is present in the X-rayed area, subjective adjustment of brightness and contrast is recommended for use with the Digora Optime digital system.

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.

Alveolar bone pattern and salivary leptin levels among premenopausal obese women / Padrão ósseo alveolar e níveis salivares de leptina entre mulheres obesas na pré-menopausa

ABSTRACT Background: Systemic bone loss may lead to more severe periodontal destruction, decreasing local bone mineral density. Aim: A cross-sectional designed was performed to study associations among alveolar bone pattern, salivary leptin concentrations, and clinical periodontal status in premenopausal obese and eutrophic women. Methods: Thirty morbid obese (G1) and 30 normal-weight (G2) women were included. Anthropometric and periodontal measurements (probing depth - PD, clinical attachment levels - CAL, presence of calculus, bleeding on probing -BOP, and plaque accumulation) were assessed. OHIP-14 was used for assessment of oral health impact on quality of life. Panoramic radiography was used to obtain the panoramic mandibular index (PMI), mandibular cortical index (MCI), and mental index (MI). Intraoral periapical (PA) radiography was taken to measure the total trabecular bone volume. Leptin was measured in saliva of fasted overnight women. Results: Groups 1 and 2 differed in all anthropometric aspects, but height. Pocket depth, calculus, BOP, and plaque index were worse in G1. No differences between groups were found considering OHIP. Normal-weight subjects showed higher proportion of dense bone trabeculae than obese subjects for pre-molars, but not for molars. Mental and panoramic mandibular indexes did not differ and were in normal level. Leptin concentration was dependent only on BMI. Conclusion: Obesity affected the periodontal conditions, the alveolar bone pattern, and the salivary leptin concentration.

RESUMO Racional: A perda óssea sistêmica pode levar à destruição periodontal mais severa, diminuindo a densidade mineral óssea local. Objetivo: Investigar as associações entre padrão ósseo alveolar, concentrações de leptina salivar e estado periodontal em mulheres obesas na pré-menopausa e eutróficas. Métodos: Foram avaliadas 30 mulheres com obesidade mórbida (G1) e 30 com peso normal (G2). Foram analisadas as medidas antropométricas e periodontais (profundidade de sondagem - PS, nível clínico de inserção - NCI, presença de cálculo, sangramento à sondagem - SS e acúmulo de placa). O impacto da saúde bucal na qualidade de vida foi mensurado por meio do questionário OHIP-14. Radiografia panorâmica foi utilizada para obter o índice mandibular panorâmico (PMI), índice cortical mandibular (MCI) e índice mental (MI); já a radiografia periapical intraoral (AF) para medir o volume ósseo trabecular total. A leptina salivar foi coletada no período da manhã com a paciente em jejum. Resultados: Os grupos 1 e 2 diferiram em todos os aspectos antropométricos, exceto em estatura. Profundidade de bolsa, cálculo, SS e índice de placa foram piores no G1. Não foram encontradas diferenças entre os grupos considerando o OHIP. Indivíduos com peso normal apresentaram maior proporção de trabéculas ósseas densas do que os obesos para pré-molares, mas não para molares. Índices radiomorfométricos não diferiram entre os grupos e estavam dentro de valores normais. A concentração de leptina esteve associada ao IMC. Conclusão: A obesidade afetou as condições periodontais, o padrão ósseo alveolar e a concentração de leptina salivar.

Comparison of automatic and visual methods used for image segmentation in Endodontics: a microCT study

Abstract To calculate root canal volume and surface area in microCT images, an image segmentation by selecting threshold values is required, which can be determined by visual or automatic methods. Visual determination is influenced by the operator's visual acuity, while the automatic method is done entirely by computer algorithms. Objective: To compare between visual and automatic segmentation, and to determine the influence of the operator's visual acuity on the reproducibility of root canal volume and area measurements. Material and methods: Images from 31 extracted human anterior teeth were scanned with a μCT scanner. Three experienced examiners performed visual image segmentation, and threshold values were recorded. Automatic segmentation was done using the "Automatic Threshold Tool" available in the dedicated software provided by the scanner's manufacturer. Volume and area measurements were performed using the threshold values determined both visually and automatically. Results: The paired Student's t-test showed no significant difference between visual and automatic segmentation methods regarding root canal volume measurements (p=0.93) and root canal surface (p=0.79). Conclusion: Although visual and automatic segmentation methods can be used to determine the threshold and calculate root canal volume and surface, the automatic method may be the most suitable for ensuring the reproducibility of threshold determination.

CBCT Post-Processing Tools to Manage the Progression of Invasive Cervical Resorption: A Case Report

Abstract This case report aimed to highlight the usefulness of cone beam computed tomography (CBCT) and its post-processing tools for the diagnosis, follow-up and treatment planning of invasive cervical resorption (ICR). A 16-year-old female patient was referred for periapical radiographic examination, which revealed an irregular but well demarcated radiolucency in the mandibular right central incisor. In addition, CBCT scanning was performed to distinguish between ICR and internal root resorption. After the diagnosis of ICR, the patient was advised to return shortly but did so only six years later. At that time, another CBCT scan was performed and CBCT registration and subtraction were done to document lesion progress. These imaging tools were able to show lesion progress and extent clearly and were fundamental for differential diagnosis and treatment decision.

Resumo Com este relato de caso clínico objetiva-se enfatizar a contribuição das ferramentas de pós-processamento aplicadas às imagens de tomografia computadorizada de feixe cônico (TCFC) no diagnóstico, acompanhamento e decisão do tratamento de reabsorção cervical invasiva (ICR). Paciente do sexo feminino, com 16 anos de idade foi encaminhada para realização de radiografia periapical e foi observada radiolucência irregular, na raiz do incisivo central inferior direito. A TCFC foi realizada no intuito de se obter diagnóstico diferencial entre ICR e reabsorção radicular interna. Após o diagnóstico de ICR, o paciente foi orientado a retornar em breve, mas o fez somente seis anos mais tarde. Fez-se assim outra tomografia e registro e subtração foram realizados para documentar a progressão da lesão. Essas ferramentas foram capazes de revelar claramente o progresso da lesão, sua real extensão e foram fundamentais para o diagnóstico diferencial e decisão de tratamento.

Impact of micronutrients supplementation on bone repair around implants: microCT and counter-torque analysis in rats

ABSTRACT The use of natural substances and micronutritional approaches has been suggested as a therapeutic alternative to benefit the bone healing associated with no side effects. Nevertheless, the influence of micronutritional interventions with therapeutic proprieties on the bone repair has yet to be intensely evaluated, and no evidence is available exploring the impact of micronutrient supplementation on the peri-implant bone healing. Objective This study investigated the effect of micronutrients supplementation on the bone repair around implants. Material and Methods One screw-shaped titanium implant was inserted in each tibia of each rat, which were assigned to: daily administration, for 30 d, of the placebo solution (Placebo group-n:18) or micronutrients supplementation (Micronutrients group-n:18), based on calcium, magnesium, zinc, and vitamin D3 intake. After, the animals were sacrificed. One of the implants was removed by applying a counter-torque force to evaluate the force to rupture the bone-implant interface. The other implant was evaluated by microcomputed tomography (CT) examination to determine the bone-to-implant contact (BIC) and the bone volume (BV/TV). Results No statistically significant differences were observed between the groups for both counter-torque values and microCT parameters (p>0.05). Conclusion Within the limits of this study, micronutrients supplementation did not provide additional benefits to the bone healing around dental implants.

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...

Effect of Low Shrinkage Monomers on Physicochemical Properties of Dental Resin Composites

The aim of this study was to evaluate the effect of low shrinkage monomers on physicochemical properties of dental resin composites. Two low shrinkage resin composites: one with a crosslink branching monomer (Kalore, GC Corp) and a novel monomer (Venus Diamond, Heraeus Kulzer) were compared to a conventional resin composite formulation (Filtek Z250, 3M/ESPE). The volumetric shrinkage was evaluated by µCT analysis (n=5) and the physicochemical properties by degree of C=C conversion (DC), flexural strength (FS) and Young's modulus (YM) (n=10). All samples were light cured by a LED device (Radii, SDI) with 16 J/cm2. The results were analysed by one-way ANOVA and Tukey test for multiple comparisons (α=0.05). No statistical difference was found between µCT shrinkage values to Kalore (1.8%) and Venus Diamond (1.7%) (p≥0.05); Z250 presented statistical highest shrinkage value (2.0%). Kalore presented higher statistical DC (60.8%) than Venus Diamond (49.5%) and Z250 (49.6%). No statistical difference was found between FS or YM properties to Venus Diamond and Z250; Kalore presented statistical lowest FS and YM properties (p≥0.05). Conclusion: Using novel monomers seem to reduce polymerization shrinkage without affecting the physicochemical properties evaluated of resin composites rather than using crosslink branching monomers.

O objetivo deste trabalho foi avaliar o efeito de monômeros de baixa contração de polimerização nas propriedades físico-químicas de resinas compostas. Duas resinas de baixa contração de polimerização com monômeros do tipo crosslink (Kalore GC Corp) ou do tipo novelar (Venus Diamond Heraeus Kulzer) foram comparadas a uma resina composta convencional (Filtek Z250 3M/ESPE). A contração de polimerização foi avaliada através da análise por µCT (n=5) e as propriedades físico-químicas através da análise do grau de conversão C=C (GC) resistência flexural (RF) e módulo de Young (MY) (n=10). Todas as amostras foram fotoativadas com uma fonte de LED (Radii SDI) com 16 J/cm2. Todos os resultados foram submetidos aos testes de análise de variância de 1 fator e ao teste de Tukey para comparações múltiplas (α=0,05). Nenhuma diferença estatística foi encontrada para os valores de contração de polimerização para Kalore (1,8 %) e Venus Diamond (1,7 %) (p≥0,05). Z250 apresentou estatisticamente maior contração de polimerização (2,0%). Kalore apresentou estatisticamente maior GC (60,8%) que Venus Diamond (49,5%) e Z250 (49,6%). Nenhuma diferença estatística foi encontrada para as propriedades RF e MY entre Venus Diamond e Z250. Kalore apresentou os menores valores estatisticos para FS e MY (p≥0,05). O monômero novelar parece reduzir a contração de polimerização sem afetar as propriedades físico-químicas avaliadas das resinas compostas de forma mais adequada que a utilização de monômeros do tipo crosslinker.

Accuracy in the diagnosis of the mental nerve loop: a comparative study between panoramic radiography and cone beam computed tomography / Precisión en el diagnóstico del bucle del nervio mental: estudio comparativo entre radiografía panorámica y tomografía computadorizada de haz cónico

Dental implant and chin osteotomy are executed on the mandible body and the mental nerve is an important anatomical limit. The aim of this research was to know the position of the mental nerve loop comparing result in panoramic radiography and cone beam computed tomography. We analyzed 94 hemimandibles and the patient sample comprised female and male subjects of ages ranging from 18 to 52 years (mean age, 35 years) selected randomly from the database of patients at the Division of Oral Radiology at Piracicaba Dental School State University of Campinas; the anterior loop (AL) of the mental nerve was evaluated regarding the presence or absence, which was classified as rectilinear or curvilinear and measurement of its length was obtained. The observations were made in the digital panoramic radiography (PR) and the cone beam computed tomography (CBCT) according to a routine technique. The frequencies of the AL identified through PR and CBCT were different: in PR the loop was identified in 42.6% of cases, and only 12.8% were bilateral. In contrast, the AL was detected in 29.8% of the samples using CBCT, with 6.4% being bilateral; Statistical comparison between PR and CBCT showed that the PR led to false-positive diagnosis of the AL in this sample. According to the results of this study, the frequency of AL is low. Thus, it can be assumed that it is not a common condition in this population.

Implantes dentales y la osteotomía de mentón son realizadas en el cuerpo mandibular y el nervio mental es un importante limite anatómico. El objetivo de esta investigación es conocer la posición del bucle del nervio mental comparando resultados entre radiografia panorámica y tomografía computadorizada de haz cónico (TCHC). Fueron analizadas 94 hemimandíbulas; la muestra de pacientes de sexo feminino y masculino con edades fluctuando entre 18 y 52 años (edad media, 35 años) seleccionados de la base de datos de pacientes de la División de Radiología de la Facultad de Odontología de Piracicaba, Universidad Estadual de Campinas; el bucle anterior (BA) del nervio mental fue evaluado según su presencia o ausencia, el cual fue clasificado como rectilíneo o curvilíneo obteniéndose el largo total del bucle; las observaciones fueron realizadas en radiografías panorámicas digitales (RP) y en TCHC de acuerdo a técnicas de rutina. La frecuencia de identificación del BA en RP y TCHC fue diferente: en la PR, el BA se identificó en un 42,6% de los casos y solo el 12,8% fue bilateral. En contraste, el BA fue detectado en el 29,8% de la muestra utilizando TCHC, con un 6,4% bilateral; la comparación estadística entre RP y TCHC muestra que la RP lleva a diagnósticos falsos positivos de la muestra de BA. De acuerdo con los resultados de este estudio, la frecuencia de BA es baja. Por este motivo se puede asumir que esta es una condición anatómica poco frecuente en la población estudiada.

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...

Novo método para posicionamento de mini-implantes por meio de planejamento computadorizado utilizando guias cirúrgicos prototipados (TAD. GUIDE / A new method for placing mini implants using computadorized tomography combined with digital models for implant planing and prototyped surgical guides

Resumo / Apesar da facilidade na técnica cirúrgica para instalação mini-implantes ortodônticos, o correto posicionamento desses dispositivos é fundamental para a estabilidade e sucesso do tratamento. Erros de posicionamento podem causar a perda prematura, reabsorções radiculares ou inviabilizar a criação dos vetores de força desejados. Guias prototipados podem transferir para a clínica o planejamento virtual realizado a partir de tomografias computadorizadas. Apresentamos um novo método que combina os modelos digitais com as tomografias computadorizadas para geração dos guias prototipados, com maior precisão e comodidade para o clínico. O uso desse tipo de guia pode aumentar ainda mais a previsibilidade e a taxa de sucesso dos mini-implantes ortodônticos.

Biomechanics of the human canine pillar based on its geometry using finite element analysis / Biomecánica del pilar canino en el cráneo humano basada en la geometría utilizando análisis de elementos finitos

This study evaluated the stress distribution based on the canine pillar geometry in human skull, using a finite element analysis. Computed tomography of human skull was used to build a finite element model, which was composed by all bony structures of canine pillar: canine eminence, canine fossa, frontal process of maxilla, glabellum and superciliary arch. A support on the bite contact of maxillary canine tooth and a resultant force of the masticatory muscles was applied in the simulation. Equivalent Von-mises and maximum principal stresses were analyzed along the structures that compose the canine pillar geometry. Von-mises stress presented high stress concentrated at the canine fossa and frontal process of maxilla. Maximum principal stress showed compression areas at the canine fossa and part of frontal process and tensile stress at canine eminence and part of the frontal process. In conclusion, the different stress areas means different force concentrations transmitted along the canine pillar geometry during a peak canine bite.

Este estudio evaluó la distribución de la tensión sobre la geometría del pilar canino en el cráneo humano, utilizando análisis de elementos finitos. Se usó la tomografía computarizada de cráneo humano para construir un modelo de elementos finitos compuesto por todas las estructuras óseas del pilar canino: eminencia canina, fosa canina, proceso frontal del maxilar, glabela y arco superciliar. Se aplicó en la simulación un soporte ubicado sobre el contacto de mordida del diente canino maxilar y una fuerza resultante de los músculos de la masticación. Tensiones Equivalentes de Von-Mises y tensiones principales máximas fueron analizadas a lo largo de las estructuras que componen la geometría de pilar canino. La tensión de Von-Mises fue alta y concentrada en la fosa canina y proceso frontal del maxilar. La tensión principal máxima mostró áreas de compresión en la fosa canina y parte del proceso frontal y la tensión de tracción en la eminencia canina y parte del proceso frontal. Las diferentes áreas de tensión significan diferentes concentraciones de tensiones transmitida a lo largo de la geometría del pilar canino durante una mordedura canina máxima.

Comparison of distance and symmetry in the mental foramen obtained in situ and in radiographic images of Brazilians / Comparação da distância e simetria dos forames mentonianos obtidos em loco e em imagens radiográficas na população brasileira

The precise location of the mental foramina is of paramount importance when using implantology to carry out oral rehabilitation procedures not affecting crucial anatomic structures. Panoramic radiography has become the imaging method of choice in many of these cases because of its lower cost and the fact that with it a general assessment of the maxillofacial complex can be made. This study set out to evaluate the distance between the mental foramina and the relationship between them and the mandibular base, and the posterior border of the mandible ramus, as well as the relationship between the bilateral mandibular foramina. The morphometric procedures were carried out by three examiners experienced in Dental Radiology, firstly on 58 human mandibles, with the aid of digital calipers and then on the respective panoramic radiographs of the mandibles, with Image J software, with and without the aid of artificial markers for delimitating the areas of interest. Using Friedman's statistical analysis, there were statistically significant differences between various measurements analyzed and compared to the gold standard, which points to the need to use more accurate imaging tests.

A localização precisa do forame mentoniano tornou-se uma necessidade premente para a execução de procedimentos de reabilitações orais, empregando a implantodontia, que não afetem estruturas anatômicas importantes, sendo a radiografia panorâmica o método de imagem de escolha em muitos desses casos por ter baixo custo e pela possibilidade de avaliação geral do complexo maxilo facial. Este trabalho teve como objetivo avaliar a distância entre os forames mentonianos e a sua relação com a base mandibular, borda posterior do ramo da mandíbula e a relação entre os forames mandibulares bilateralmente. As morfometrias foram realizadas por três experientes avaliadores em Radiologia Odontológica, primeiramente em 58 mandíbulas humanas, com o auxílio de paquímetro digital e depois nas respectivas radiografias panorâmicas das mandíbulas, com o software Image J, com e sem o auxílio de marcadores artificiais para delimitação das áreas de interesse. Por meio da utilização da análise estatística de Friedman, observaram-se diferenças estatísticas significativas em diversas medidas analisadas, quando comparadas ao padrão ouro, fato que demonstra a necessidade da utilização de exames por imagem mais precisos.