Optimizing cone-beam computed tomography exposure for an effective radiation dose and image quality balance.

Purpose: The aim of this study was to evaluate the influence of different cone-beam computed tomography (CBCT) acquisition protocols on reducing the effective radiation dose while maintaining image quality. Materials and Methods: The effective dose emitted by a CBCT device was calculated using thermoluminescent dosimeters placed in a Rando Alderson phantom. Image quality was assessed by 3 experienced evaluators. The relationship between image quality and confidence was evaluated using the Fisher exact test, and the agreement among raters was assessed using the kappa test. Multiple linear regression analysis was performed to investigate whether the technical parameters could predict the effective dose. P-values<0.05 were considered to indicate statistical significance. Results: The optimized protocol (3 mA, 99 kVp, and 450 projection images) demonstrated good image quality and a lower effective dose for radiation-sensitive organs. Image quality and confidence had consistent values for all structures (P<0.05). Multiple linear regression analysis resulted in a statistically significant model. The milliamperage (b=0.504; t=3.406; P=0.027), kilovoltage peak (b=0.589; t=3.979; P=0.016) and number of projection images (b=0.557; t=3.762; P=0.020) were predictors of the effective dose. Conclusion: Optimized CBCT acquisition protocols can significantly reduce the effective radiation dose while maintaining acceptable image quality by adjusting the milliamperage and projection images.

Determination of the pubertal growth spurt by artificial intelligence analysis of cervical vertebrae maturation in lateral cephalometric radiographs.

OBJECTIVE: This study aimed to assess the performance of a convolutional neural network (CNN) model in detecting the pubertal growth spurt by analyzing cervical vertebrae maturation (CVM) in lateral cephalometric radiographs (LCRs). STUDY DESIGN: In total, 600 LCRs of patients from 6 to 17 years old were selected. Three radiologists independently and blindly classified the maturation stages of the LCRs and defined the difficulty of each classification. Subsequently, the stage and level of difficulty were determined by consensus. LCRs were distributed between training, validation, and test datasets across 4 CNN-based models. The models' responses were compared with the radiologists' reference standard, and the architecture with the highest success rate was selected for evaluation. Models were developed using full and cropped LCRs with original and simplified maturation classifications. RESULTS: In the simplified classification, the Inception-v3 CNN yielded an accuracy of 74% and 75%, with recall and precision values of 61% and 62%, for full and cropped LCRs, respectively. It achieved 61% and 62% total success rates with full and cropped LCRs, respectively, reaching 72.7% for easy-to-classify cropped cases. CONCLUSION: Overall, the CNN model demonstrated potential for determining the maturation status regarding the pubertal growth spurt through images of the cervical vertebrae. It may be useful as an initial assessment tool or as an aid for optimizing the assessment and treatment decisions of the clinician.

Assessment of accuracy and reproducibility of cephalometric identification performed by 2 artificial intelligence-driven tracing applications and human examiners.

OBJECTIVE: To assess the accuracy and reproducibility of cephalometric landmark identification performed by 2 artificial intelligence (AI)-driven applications (CefBot and WebCeph) and human examiners. STUDY DESIGN: Lateral cephalometric radiographs of 10 skulls containing 0.5 mm lead spheres directly placed at 10 cephalometric landmarks were obtained as the reference standard. Ten radiographs without spheres were obtained from the same skulls for identification of cephalometric points performed by the AI applications and 10 examiners. The x- and y-coordinate values of the cephalometric points identified by the AI applications and examiners were compared with those from the reference standard images using one-way analysis of variance and the Dunnet post-hoc test. The intraclass correlation coefficient (ICC) was used to evaluate reproducibility. Mean radial error (MRE) in identification was calculated with respect to the reference standard. Statistical significance was established at P < .05. RESULTS: Landmark identification by CefBot and the examiners did not exhibit significant differences from the reference standard on either axis (P > .05). WebCeph produced a significant difference (P < .05) in 4 and 6 points on the x- and y-axes, respectively. Reproducibility was excellent for CefBot and the examiners (ICC ≥ 0.9943) and good for WebCeph (ICC ≥ 0.7868). MREs of CefBot and the examiners were similar. CONCLUSION: With results similar to those of human examiners, CefBot demonstrated excellent reliability and can aid in cephalometric applications. WebCeph produced significant errors.

Influence of an adjacent zirconium implant, tube current, and metal artifact reduction algorithm on horizontal root fracture diagnosis in cone beam computed tomography.

OBJECTIVE: We evaluated the influence of an adjacent zirconium implant, tube current (mA), and a metal artifact reduction algorithm (MARA) on horizontal root fracture (HRF) diagnosis in cone beam computed tomography (CBCT). STUDY DESIGN: Nineteen teeth (9 with HRF, 10 without) were individually placed in a human maxilla. Scan volumes were acquired without and with a zirconium implant adjacent to the tooth at settings of 4, 8, and 10 mA, with MARA disabled and enabled, using a 5×5 cm field of view, 0.085-mm voxel size, and 90 kV. Four maxillofacial radiologists individually assessed the scans. Diagnostic metrics were compared by multiway analysis of variance (α=5%). Inter- and intraexaminer agreements for HRF diagnosis were evaluated with the weighted kappa test. RESULTS: Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were significantly lower in the presence of the implant (P≤.005). AUC values were higher in scans obtained with 8 and 10 mA compared with 4 mA (P=0.010), but 10 mA without MARA was better with the implant present. MARA did not significantly influence outcomes (P≥0.240). Inter- and intraexaminer agreements ranged from moderate to almost perfect. CONCLUSIONS: The presence of the zirconium implant impairs HRF detection. Settings of 8 or 10 mA improve HRF detection regardless MARA condition without the implant. With an adjacent implant, 10 mA without MARA is recommended to improve diagnostic performance.

The effect of voxel and field of view size on the volumetric alteration artifact of high-density materials with 2 cone beam computed tomography devices.

OBJECTIVE: We investigated the influence of voxel and field of view (FOV) sizes on expression of the volumetric alteration artifact (VAA) of 5 high-density materials in 2 cone beam computed tomography (CBCT) devices. STUDY DESIGN: Cylinders of amalgam, cobalt-chromium, gutta-percha, titanium, and zirconium were individually positioned in a polymethyl methacrylate phantom. OP300 Maxio and ProMax 3D Classic CBCT devices were used to acquire images with varying voxel and FOV sizes, totaling 585 scans. Two evaluators segmented the high-density cylinder images to obtain the tomographic volumes. The difference between the tomographic and physical volume of each cylinder (i.e., volumetric alteration) was calculated. Statistical analysis was conducted with multiway ANOVA and the Tukey post hoc test (α = 5%). Evaluator reliability was measured with the intraclass correlation coefficient (ICC). RESULTS: All studied parameters and nearly all interactions influenced the VAA (P < .05). The post hoc test demonstrated less volumetric alteration for the smallest voxel sizes, 61 × 78 mm FOV, and gutta-percha for OP300, and for the smallest voxel sizes, 80 × 80 mm FOV, and gutta-percha and titanium for ProMax 3D (P < .05). The ICC demonstrated perfect reliability (1.00). CONCLUSIONS: Voxel and FOV sizes influenced VAA expression. Using smaller voxel sizes, the 61 × 78 mm FOV for OP300 and the 80 × 80 mm FOV for ProMax 3D, and materials with lower density and lower atomic number reduced VAA expression.

Mapping artifacts generated in a tooth adjacent to titanium and zirconia implants located in the endomass and exomass in cone beam computed tomography: an ex vivo study.

OBJECTIVE: We evaluated artifact expression in a root adjacent to a dental implant located in the endomass or exomass in cone beam computed tomography (CBCT). STUDY DESIGN: We placed a single titanium or zirconia implant adjacent to a premolar root in a dried human mandible and acquired CBCT scans using an OP300 Maxio and a Picasso Trio 3D unit exposing a 5x5cm field of view with the implant in the endomass or exomass (implant groups) or without an implant (control group). We measured the mean gray values (MGVs) for 8 lines of interest (LOIs) around the root canal of the premolar and compared the MGVs by analysis of variance, with significance established at P < 0.05. RESULTS: For the OP300 Maxio scans, the MGVs of both implant groups in the endomass were lower than the MGVs of the control group. In the exomass, the titanium group had MGVs similar to the control group, but the zirconia group produced significantly lower MGVs than control and titanium groups (P <.0001), indicating the presence of hypodense artifacts. For the Picasso Trio 3D scans, the MGVs of both implant groups in the endomass were similar to the MGVs of the control group. In the exomass, the zirconia group generated lower MGVs than control and titanium groups (P <.0001), indicating hypodense artifacts. CONCLUSIONS: When performing CBCT examination, titanium implants produce less artifact expression in the exomass, and zirconia implants have less artifact expression in the endomass.

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.

Disinfection of intraoral photostimulable phosphor plates with 70% ethyl alcohol and 70% isopropyl alcohol alters image contrast and produces image artifacts.

OBJECTIVE: This study evaluated changes in image quality and the presence and size of artifacts on radiographs obtained with photostimulable phosphor (PSP) plates after disinfection with 70% ethyl alcohol and 70% isopropyl alcohol. STUDY DESIGN: Eight PSP receptors (4 Express and 4 VistaScan) were used for the investigation. Two Express and 2 VistaScan receptors were disinfected with 70% ethyl alcohol, and 2 Express and 2 VistaScan receptors were disinfected with 70% isopropyl alcohol. Before disinfection and after every 5 disinfections, 2 radiographs of an aluminum stepwedge and 2 radiographs of an acrylic block were acquired using each receptor. The gray values of the radiographs were analyzed regarding contrast, density, uniformity, and noise. Four oral radiologists evaluated the images for the presence of artifacts, and 2 measured the artifacts. RESULTS: Differences in image contrast were significantly larger with isopropyl alcohol (P < .0001). Artifact size was significantly greater with the VistaScan system when isopropyl alcohol was used as the disinfectant (P < .0001). The correlation between the number of disinfections and artifact size was moderately positive with the Express system (P < .05) and strongly positive with the VistaScan system (P < .05) with both disinfectants. CONCLUSIONS: Small artifacts restricted to the edges of the image were observed with disinfection using both types of alcohol, and a positive correlation was found between artifact size and the number of disinfections. However, artifacts appeared earlier and of greater size with the VistaScan system when disinfected with 70% isopropyl alcohol. Thus, we recommend using 70% ethyl alcohol to disinfect PSP receptors, with attention placed on its action and evaporation times.

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.

Influence of extensive use of a photostimulable phosphor receptor on the diagnosis of proximal carious lesions: An in vitro study.

OBJECTIVE: The aim of this study was to evaluate the influence of the extensive use of a photostimulable phosphor (PSP) receptor on the diagnosis of proximal carious lesions. STUDY DESIGN: Forty posterior teeth were paired and mounted in 20 phantoms. Using a PSP receptor of the Express intraoral system, 1 radiograph of each phantom was acquired, totaling 20 radiographs (group 1). After 400 acquisitions, another radiograph of each phantom was obtained, totaling 20 new radiographs (group 2). This procedure was also done after 800 (group 3), 1,200 (group 4), and 1,600 (group 5) acquisitions, resulting in 100 radiographs. Another 40 radiographs (20 phantoms × 2 groups) were obtained with a second PSP sensor to evaluate the diagnostic replicability of the receptors. All 140 radiographs were assessed independently by 5 examiners for the presence of proximal caries. Area under the receiver operating characteristic curve, sensitivity, and specificity were calculated and compared among the groups by analysis of variance. The Student t test evaluated the diagnostic replicability of the receptors. The significance level was set at 5% (P < .05). RESULTS: The diagnostic outcomes for proximal caries did not differ among the groups (P ≥ .37). The diagnostic values did not differ among the radiographs acquired with the 2 PSP receptors (P ≥ .75). CONCLUSIONS: The diagnosis of proximal carious lesions was not affected by extensive use of the PSP receptor.

Morphological and topographic evaluation of the mandibular canal and its relationship with the facial profile, skeletal class, and sex.

PURPOSE: The aim of this study was to evaluate the morphology and topography of the mandibular canal in patients with different facial profiles, skeletal classes, and sexes. METHODS: Cone-beam computed tomography volumes of 103 patients were classified according to facial profile and skeletal class. Two examiners classified the mandibular canal into a linear, spoon-shaped, elliptical arc, or turning curvature and measured four related linear distances. The most frequent mandibular canal curvature was identified and multi-way ANOVA with Tukey's test compared the linear measurements between facial types, skeletal class, and sexes (α = 0.05). Kappa and intraclass correlation coefficients were used to assess the reproducibility of qualitative and quantitative variables, respectively. RESULTS: The examiners showed excellent reproducibility. The four curvatures of the mandibular canal were found, but the spoon-shaped and elliptical arch were the most frequent. No significant differences were observed for most of the linear measurements between the different facial profiles, skeletal classes, and sexes (p > 0.05). CONCLUSION: Spoon-shaped and elliptical arch are the most frequent curvatures of the mandibular canal; furthermore, its morphology and topography seem to be little influenced by the facial profile, skeletal class, and sex.

Is the efficacy of cone beam computed tomography in the diagnosis of tooth ankylosis influenced by dose reduction protocols?

OBJECTIVE: To evaluate the diagnostic efficacy of cone beam computed tomography (CBCT) examinations acquired with varying dose protocols in the diagnosis of simulated tooth ankylosis (TA). STUDY DESIGN: Tooth ankylosis was simulated in 15 of 30 teeth, and CBCT examinations were acquired at 3 mA levels (8, 6.3, and 5) and 3 voxel sizes (0.08, 0.125, and 0.2 mm). Four radiologists independently assessed the presence of TA using a 5-point scale. Sensitivity, specificity, and area under the curve (AUC) obtained through receiver operating characteristic analysis were compared among mA levels and voxel sizes using two-way analysis of variance (α = 0.05). Intra- and interexaminer reliability levels were assessed with the weighted kappa examination. RESULTS: Sensitivity was low (0.32-0.49), and specificity was reasonably high (0.71-0.83). Mean values of AUC were low, ranging between 0.54 and 0.67, which reveals poor overall discrimination between health and disease. The detection of TA was not significantly influenced by mA level or voxel size (P > .05). Intra- and interexaminer agreements ranged from slight to moderate (0.160-0.535) and from fair to substantial (0.236-0.697), respectively. CONCLUSIONS: Despite the limited efficacy of CBCT for TA detection, when indicated as a complementary examination, mA reduction should be considered for dose optimization purposes.

Impact of COVID-19 pandemic on dental education: perception of professors and students / Impacto de la pandemia COVID-19 en educación dental: percepción de estudiantes y profesores

Abstract The objective of this study was to evaluate perception and feelings experienced by dentistry professors and students about distance learning during the COVID-19 pandemic. Fifty professors and fifty- two students reported the perceptions and implications of distance learning imposed by the pandemic of COVID-19. The participants' answers were analyzed using the qualitative-quantitative method of the collective subject's discourse. The answers were summarized in central ideas, distributed in absolute and relative frequency. The answers with similar central ideas were grouped, obtaining the discourse of the collective subject. The similar central ideas about distance learning addressed by professors and students were: suitable for didactic courses; limited laboratory and clinical courses, and internet access difficulties. Specifically for professors: a complement to classroom teaching; stress and learning with digital technologies; difficulty in reconciling classes with domestic activities; concerns with motivation and interaction with students; asynchronous lectures favor knowledge fixation, and synchronous lectures favor interaction with students; unreliable assessment methods; concern about returning to face-to-face classes. For the students: it was applied to all courses; demotivating; fundamental to guide studies; professors' commitment; long lectures; excessive school activities; difficult attendance control and evaluation; the comfort of being at home; impact on research. Professors considered distance learning as a learning opportunity on how to use digital technologies but too limited for lab and clinical activities and interaction with students. Students found it discouraging due to the absence of practical classes and excessive school activities.

Resumen: Evaluar la percepción y los sentimientos manifestados por profesores y estudiantes de odontología sobre la educación a distancia durante la pandemia por COVID-19. 50 profesores y 52 estudiantes informaron las percepciones e implicaciones del aprendizaje a distancia impuestas por motivo de la pandemia de COVID-19. Respuestas de los participantes fueron analizadas utilizando el método cualitativo-cuantitativo del discurso del sujeto colectivo. Respuestas se agruparon en ideas centrales, obteniendo el discurso del sujeto colectivo y fueron distribuidas en frecuencia absoluta y relativa. Ideas centrales similares entre profesores y estudiantes sobre el aprendizaje a distancia fueron: a) es adecuado para cursos didácticos; b) limitado para cursos de laboratorio y clínicos; c) presenta dificultades devido al acceso a Internet. Específicamente para profesores: a) complemento a la docencia en el aula; b) aumenta el estrés devido a la curva de aprendizaje con tecnologías digitales; c) dificultad para conciliar las clases con las actividades domésticas; d) preocupaciones con la motivación y la interacción con los estudiantes; e) las clases asincrónicas favorecen la fijación del conocimiento y las clases sincrónicas favorecen la interacción con los estudiantes; f) métodos de evaluación poco fiables; y g) preocupación por volver a las clases presenciales. Para los estudiantes: a) se aplicó a todos los cursos; b) desmotivador fundamental para orientar los estudios; c) compromiso de los profesores; d) conferencias largas; e) actividades escolares excesivas; f) difícil control y evaluación de asistencia; g) la comodidad de estar en casa; y h) impacto en la investigación. Profesores consideraron el aprendizaje a distancia como una oportunidad de aprendizaje sobre cómo utilizar las tecnologías digitales, pero demasiado limitado para las actividades de laboratorio y clínicas y la interacción con los estudiantes. Estudiantes lo encontraron desalentador debido a la ausencia de clases prácticas y al exceso de actividades escolares.

The metal post material influences the performance of artefact reduction algorithms in CBCT images

Abstract This study aimed to assess the effect of the MAR tool on the expression of artefacts in different regions of a tooth restored with different types of metal posts. Alveolar sockets (anterior, and posterior region) of a mandible and an unirradicular tooth were used. Cone beam computed tomography scans of the tooth without a metal post, and with cobalt-chromium (Co-Cr), nickel-chromium (Ni-Cr), or silver-palladium (Ag-Pd) were individually obtained, with 2 MAR conditions: disabled, and enabled. In an axial reconstruction, lines of interest (LOIs) were set around the canal: 4 in oblique (mesiobuccal, distobuccal, mesiolingual, distolingual) directions, and 4 in orthogonal (mesial, distal, buccal, lingual) directions. Beam-hardening artefacts expression was determined by calculating the difference in the mean of gray values (DMGV) between the experimental and control groups for each LOI. There was no significant difference in the DMGV values between "without MAR" and "with MAR" for any LOI, in neither anterior nor posterior mandible (p>0.05), for the Ni-Cr and Co-Cr groups. For the Ag-Pd, significant differences in the DMGV values were observed between "without MAR" and "with MAR" for most LOIs (p<0.05), mainly in oblique directions in the anterior region, and mesio-distal direction in the posterior region. MAR acted mostly in hypodense artefacts (negative DMGV). The effectiveness of the MAR tool of the OP300 CBCT unit varied according to the post material tested. It was effective in reducing the expression of artefacts raised by the Ag-Pd post, mainly in the tooth regions affected by hypodense artefacts, regardless of the mandibular region.

Resumo O objetivo nesse estudo foi avaliar o efeito da ferramenta de redução de artefato (FRA) na expressão de artefatos em diferentes regiões de um dente restaurado com diferentes tipos de pinos metálicos. Foram usados ​​alvéolos (regiões anterior e posterior) de uma mandíbula e um dente unirradicular. Imagens de tomografia computadorizada de feixe cônico do dente sem pino metálico intracanal e com pinos de cobalto-cromo (Co-Cr), níquel-cromo (Ni-Cr) ou prata-paládio (Ag-Pd) foram individualmente obtidas, com 2 condições de FRA: desativada e ativada. Em uma reconstrução axial, linhas de interesse (LOIs) foram definidas ao redor do canal: 4 em direções oblíquas (mésio-vestibular, disto-vestibular, mésio-lingual e disto-lingual) e 4 em direções ortogonais (mesial, distal, vestibular e lingual). A expressão dos artefatos de endurecimento do feixe foi determinada pelo cálculo da diferença na média dos valores de cinza (DMVC) entre os grupos experimental e controle para cada LOI. Não houve diferença significativa nos valores de DMVC entre as condições "sem FRA" e "com FRA" para nenhuma das LOIs, nem na região anterior nem na região posterior da mandíbula (p>0,05), para os grupos Ni-Cr e Co-Cr. Para o Ag-Pd, diferenças significativas nos valores de DMVC foram observadas entre "sem FRA" e "com FRA" para a maioria das LOIs (p<0,05), principalmente nas direções oblíquas na região anterior, e na direção mesio-distal na região posterior. A FRA atuou principalmente em artefatos hipodensos (DMVC negativos). A eficácia da FRA disponível no aparelho de TCFC OP300 variou de acordo com o material do pino testado. Ela foi efetiva na redução da expressão de artefatos originados por pinos de Ag-Pd, principalmente nas regiões do dente afetadas por artefatos hipodensos, independentemente da região mandibular.

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.

Digital technology in dental education during COVID-19 pandemic: worldwide experience of professors and students / Tecnología digital en la educación odontológica durante la pandemia por COVID-19: experiencia mundial de profesores y estudiantes

ABSTRACT: The objective of this study was to assess the use and experience with digital communication tools among dentistry professors and students to adapt to distance learning during the Covid-19 pandemic. Nine hundread and ninety five participants (479 dentistry professors and 516 students) from countries in North America, Latin America, Brazil, Europe, Asia, Oceania, and the Middle East answered a questionnaire about motivation/stress/anxiety; practice with digital technologies; synchronous/asynchronous communication technologies (difficulties/benefits), and which ones would they prefer using when returning to college. Data were analyzed by the Chi-square test and Fisher's exact (α=0.05). Motivation was more affected among the female professors, male students, and Brazilians (p<0.05). Concern about the academic future, was higher among female students, up to 30 years old, from Latin America and Brazil, and lower for European professors (p<0.05). Anxiety and stress were higher for undergraduate students up to 20 years old from Latin America and Brazil (p<0.05). European professors used more synchronous videoconferencing services for lectures/questions, while Brazilians used more text messaging applications for answering questions (p<0.05). Latin American professors used more surveys for evaluation (p<0.05). Brazilian professors indicated that they would use "online meetings" and "survey administration services" when returning to face-to-face activities and European professors/students would use "email" (p<0.05). Professors from Asia/Oceania/Middle East and professors/students from Brazil indicated "remote activities were important for students not to be inactive" (p<0.05). Efforts were made to adapt Dentistry's teaching to distance learning during the COVID-19 pandemic. However, the technologies used for this, feelings, and experiences differed between professors and students.

RESUMEN: El objetivo de este estudio fue evaluar el uso y la experiencia con herramientas de comunicación digital entre profesores y estudiantes de odontología para adaptarse al aprendizaje a distancia durante la pandemia Covid-19. Novecientos noventa y cinco participantes (479 profesores y 516 estudiantes de odontología) de países de diferentes regiones de América del Norte, América Latina, Brasil, Europa, Asia, Oceanía y Oriente Medio respondieron un cuestionario sobre motivación/ estrés/ansiedad; práctica con tecnologías digitales; tecnologías de comunicación sincrónicas/asincrónicas (dificultades/beneficios), y cuáles continuarían usando al regresar a la universidad. Los datos se analizaron mediante las pruebas Chi-cuadrado y exacta de Fisher (α=0,05). La motivación se vio más afectada entre las profesoras, estudiantes y brasileños (p<0,05). La preocupación por el futuro académico fue mayor entre las estudiantes, hasta los 30 años, de América Latina y Brasil, y menor para el profesorado europeo (p<0,05). El estrés fue mayor para el estudiantado de pregrado de Latinoamérica y Brasil hasta los 20 años (p<0.05). El profesorado europeo utilizó más servicios de videoconferencia sincrónica para clases y consultas, mientras que el brasileño utilizó más aplicaciones de mensajería de texto para consultas (p<0,05). El profesorado latinoamericano utilizó más encuestas para evaluación (p<0.05). El profesorado brasileño indicó que utilizaría "reuniones en línea" y "servicios de encuestas" cuando regresaran a la presencialidad, mientras que el profesorado/ estudiantado europeo utilizaría "correo electrónico" (p<0,05). El profesorado de Asia/ Oceanía/Medio Oriente y profesorado/estudiantado de Brasil indicó que "las actividades remotas eran importantes para que el estudiantado no estuviera inactivo" (p<0,05). Se relizaron esfuerzos para adaptar la enseñanza de la Odontología al aprendizaje a distancia durante la pandemia de COVID-19. Sin embargo, las tecnologías utilizadas y las experiencias difirieron entre profesores y estudiantes.

Prevalence of Errors and Number of Retakes in Panoramic Radiography: Influence of Professional Training and Patient Characteristics

ABSTRACT: Panoramic radiography has clinical importance in several dental specialties. The objective of this study was to evaluate the influence of professionals' experience and patient characteristics (age group and dental absence) in the prevalence of errors and the number of retakes in the panoramic radiography.771 panoramic radiographs were evaluated and classified according to the group of patients (children, dentulous adults, total edentulous adults, and anterior edentulous adults) and professionals who performed the technique (novice and experienced). The association between frequency and type of error, group of patients, professionals' experience, and number of retakes was performed by the Chi-square and Fisher's exact test (a=0.05). There was no significant association between the frequency of errors or retakes of the radiograph s and the professionals' experience or patients' characteristics (p<0.05). The errors "turned head" and "tongue not against the palate," "chin tipped low", "chin not resting on the support," "patient movement during exposure," and "lead apron artifact" showed significantly higher frequency of retake (p<0.05). The most frequent type of error was due to the failure to position the tongue against the palate for all patients and both groups of professionals. The frequency of errors in the panoramic radiography occurs regardless of the professionals' experience, and age and dental absence of the patients. Error occurs mainly due to the lack of patient collaboration, and the examination is rarely repeated by the professionals.

RESUMEN: La radiografía panorámica es de importancia clínica en varias especialidades dentales. El objetivo de este estudio fue evaluar la experiencia de los profesionales y las características de los pacientes (grupo etario y ausencia dentaria) en la prevalencia de errores y el número de repeticiones en la radiografía panorámica.771 radiografías panorámicas fueron evaluadas y clasificadas según la grupo de pacientes (niños, adultos desdentados, adultos desdentados totales y adultos desdentados anteriores) y profesionales que realizaron la técnica (novatos y experimentados). La asociación entre frecuencia y tipo de error, grupo de pacientes, experiencia de los profesionales y número de repeticiones se realizó mediante la prueba de Chicuadrado y exacta de Fisher (a = 0,05). No hubo asociación significativa entre la frecuencia de errores o repetición de las radiografías y la experiencia de los profesionales o las características de los pacientes (p <0,05). Los errores "cabeza girada" y "lengua no contra el paladar", "mentón inclinado hacia abajo", "mentón no apoyado en el soporte", "movimiento del paciente durante la exposición" y "artefacto del delantal de plomo" mostraron una frecuencia de repetición significativamente mayor (p < 0,05). El error más frecuente se debió a la falta de posicionamiento de la lengua contra el paladar para todos los pacientes y en ambos grupos de profesionales. La frecuencia de errores en la radiografía panorámica ocurre independientemente de la experiencia de los profesionales, edad y ausencia dentaria del pacientes. El error se produce principalmente por la falta de colaboración del paciente, y los profesionales rara vez repiten el examen.

Can the Incorporation of a Lead Foil on the Backside of Digital Receptors Produce a Better Endodontic Diagnosis?

ABSTRACT: This study evaluated influence of addition of lead foil coupled to different types of digital receptors on image noise and on diagnosis of fractured instruments in teeth without and with root filling. Twenty-six molars had their root canals (n=67) cleaned and shaped and were divided into groups with and without root filling and with and without fractured instruments. Images were acquired in PSP and CMOS sensor, with and without addition of a lead foil coupled to the digital receptors. Diagnostic values were obtained by the area under the ROC curve, and one-way ANOVA compared the groups. Noise in images was measured by the standard deviation of mean gray values in images with and without the lead foil, and compared by two-way ANOVA (a=0.05). Addition of lead foil did not interfere in the diagnostic accuracy for both digital systems (p>0.05) and did not decrease noise in the images (p>0.05). However, independently of the addition of the lead foil, the phosphor-storage plate presented higher noise compared to the sensor (p ?0.05). Addition of lead foil to the digital receptor did not interfere in image noise and with the diagnostic accuracy for detecting fracured endodontic instrument in ex-vivo conditions.

RESUMEN: Este estudio evaluó la influencia de láminas de plomo acopladas a diferentes tipos de receptores digitales sobre el ruido de la imagen y el diagnóstico de instrumentos fracturados en dientes sin y con obturación radicular. Se limpiaron y moldearon 26 molares (n = 67), se dividieron en grupos con y sin relleno radicular y con y sin instrumentos fracturados. Las imágenes se adquirieron en el sensor PSP y CMOS, con y sin adición de una lámina de plomo acoplada a los receptores digitales. Los valores diagnósticos se obtuvieron por el área bajo la curva ROC y con ANOVA de una vía comparó los grupos. El ruido en las imágenes se midió mediante la desviación estándar de los valores medios de gris en las imágenes con y sin la lámina de plomo, y se comparó mediante ANOVA bidireccional (a = 0,05). La adición de lámina de plomo no interfirió en la precisión diagnóstica de ambos sistemas digitales (p> 0,05) y no disminuyó el ruido en las imágenes (p> 0,05). Sin embargo, independientemente de la adición de la lámina de plomo, la placa de almacenamiento de fósforo presentó mayor ruido en comparación con el sensor (p?0,05). La adición de lámina de plomo al receptor digital no interfirió con el ruido de la imagen y con la precisión diagnóstica para detectar el instrumento endodóntico fracturado en condiciones ex vivo.

Influence of different viewing conditions on the detection of fractured endodontic instruments using periapical radiographs at 3 projection angles.

OBJECTIVES: The objective of this study was to assess the influence of ambient lighting levels and horizontal viewing angle (HVA) on the radiographic detection of fractured endodontic instruments in root canals in extracted human mandibular molars. STUDY DESIGN: Thirty-two root canals were selected. Endodontic instrument fracture was induced in 24 canals, and all canals were endodontially treated. Periapical radiographs were obtained at orthoradial, mesioradial, and distoradial projection angles. Five oral radiologists examined the radiographs for detection of fractured endodontic instruments under 3 ambient lighting levels (high, 450 lux; medium, 28 lux; and low, 2.5 lux) and 3 HVAs (90°, 67.5°, and 45°). Area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, and specificity were calculated and compared by 2-way analysis of variance using Tukey post hoc tests (α = .05). RESULTS: AUROC data indicated that ambient lighting (P = .739) and HVA (P = .238) did not significantly influence the detection of fractured endodontic instruments. Overall mean diagnostic values were 0.745, 0.57, 0.46, and 0.90 for AUROC, accuracy, sensitivity, and specificity, respectively. CONCLUSIONS: The viewing conditions assessed in this study did not influence the radiographic detection of fractured endodontic instruments in root canals.

Dimorfismo sexual em tomografias computadorizadas de crânios de brasileiros / Sex dimorphism in computerized tomography of Brazilians skulls

Buscou-se estimar o sexo por meio de medidas lineares obtidas em 200 tomografias computadorizadas (TCs) de crânios e mandíbulas do Biobanco Osteológico e Tomográfico da Faculdade de Odontologia de Piracicaba. Foram realizadas sete medidas lineares (parede posterior da sela turca à espinha nasal anterior; parede posterior da sela turca ao zígio direito; parede posterior da sela turca ao zígio esquerdo; zígio direito ao zígio esquerdo; forame infra-orbitário direito ao forame infra-orbitário esquerdo; forame infra-orbitário esquerdo à espinha nasal anterior e; forame infra-orbitário direito à espinha nasal anterior) utilizando o software OnDemand3D™. Para calibração foi usado o Teste estatístico ICC (coeficiente de correlação intraclasse), segundo Szklo e Nieto (2000) e a análise dos dados utilizou o teste de Kolmogorov-Smirnov, teste t, o teste de Pearson e uma regressão logística pelo método de Stepwise-Forward (Wald) e teste de Shapiro-Wilke e Levene para analisar a distribuição e a igualdade de variâncias das variáveis, respectivamente. Os resultados mostraram que as medidas realizadas apresentaram dimorfismo, exceto a medida forame infra-orbitário direito ao forame infra-orbitário esquerdo. Foi possível criar um modelo de regressão logística [Logito Almeida=36.560+(-0.088*PPST-ENA)+(-0.233*ZD-ZE)+0.140*FIO E-FIO D+(-0.194*FIOE-ENA)], este resulta em 79.1% de sensibilidade, 84.4% de especificidade e 82.0% de acurácia. Concluiu-se que o modelo de regressão logística obtido permite a estimativa do sexo em TCs de brasileiros, podendo ser utilizado como metodologia auxiliar no processo de identificação humana.