Aplicabilidade da reconstrução facial em 3D-TC para identificação individual forense

Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) craniometric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution.A tomografia computadorizada (TC) tem sido utilizada em diversas áreas clínicas da Odontologia; utilizam-se tanto seus cortes originais quanto as reconstruções em duas e três dimensões (2D-TC e 3D-TC). O presente estudo propõe avaliar a precisão das medidas lineares realizadas na 3D-TC, utilizando a craniometria, para fins de identificação individual na Odontologia Forense. Cinco cabeças de cadáveres foram submetidas a tomografia computadorizada em espiral por meio de cortes axiais e reconstruções em 3D-TC foram obtidas por meio da técnica de volume, utilizando recursos da computação gráfica. Medidas craniométricas (n = 10) foram determinadas nas imagens em 3D-TC por dois examinadores independentemente, duas vezes cada um, e uma análise de erro padrão percentual das medidas intra- e inter-examinadores foi realizada. Os resultados demonstraram um erro padrão percentual baixo apresentado por essas medidas, variando entre 0,85% e 3,09%. Em conclusão, as medidas lineares obtidas nas estruturas ósseas e tegumentares foram consideradas precisas em 3D-TC, com alta qualidade e resolução de imagem

Comparison between cone-beam and multislice computed tomography for identification of simulated bone lesions

There are many studies that compare the accuracy of multislice (MSCT) and cone beam (CBCT) computed tomography for evaluations in the maxillofacial region. However, further studies comparing both acquisition techniques for the evaluation of simulated mandibular bone lesions are needed. The aim of this study was to compare the accuracy of MSCT and CBCT in the diagnosis of simulated mandibular bone lesions by means of cross sectional images and axial/MPR slices. Lesions with different dimensions, shape and locularity were produced in 15 dry mandibles. The images were obtained following the cross sectional and axial/MPR (Multiplanar Reconstruction) imaging protocols and were interpreted independently. CBCT and MSCT showed similar results in depicting the percentage of cortical bone involvement, with great sensitivity and specificity (p < 0.005). There were no significant intra- or inter-examiner differences between axial/MPR images and cross sectional images with regard to sensitivity and specificity. CBCT showed results similar to those of MSCT for the identification of the number of simulated bone lesions. Cross sectional slices and axial/MPR images presented high accuracy, proving useful for bone lesion diagnosis.(FAPESP) São Paulo Research Foundation(CAPES) Coordination for the Advancement of Higher Education Personne

Modalidades de imagem na osteonecrose dos maxilares relacionada à medicamentos: revisão de literatura

Osteonecrosis occurs by cellular death of the bone tissue due to an irreversible external factor. This disorder may be clinically unidentified in the early stages and result in degradation of the bone architectural structure, leading to pain, bone destruction, and loss of function. Thus, imaging exams become relevant to the recognition and definition of the bone necroses. The aim of this study was to review the literature on imaging exams frequently used for the diagnosis and evaluation of patients undergoing drug therapies associated with osteonecrosis of the jaw, such as panoramic radiography, computed tomography, magnetic resonance imaging and bone scintigraphy.A osteonecrose ocorre pela morte celular do tecido ósseo devido a um fator externo irreversível. Esse distúrbio pode não ser clinicamente identificado nos estágios iniciais gerando quadros de dor, destruição da arquitetura óssea e perda de função. Assim, os exames de imagem se tornam relevantes para o reconhecimento e a definição das necroses ósseas. O objetivo deste estudo foi revisar a literatura a respeito das diferentes modalidades de exames de imagem frequentemente utilizados para diagnóstico e avaliação de pacientes submetidos a terapias medicamentosas associadas à osteonecrose dos maxilares, como a radiografia panorâmica, tomografia computadorizada, ressonância magnética e cintilografia óssea

Indução de artefato por materiais endodônticos: uma análise de TCFC

Metallic objects, such as intracanal posts and restorations, may produce severe interference, thus diminishing the quality of CBCT imaging. Objective: The purpose of this study was to analyze the influence of conventional and bioceramic gutta-percha points on the production of artifacts in CBCT images. Methods: Extracted single- -rooted premolar teeth (n=20) were instrumented and scanned with a CBCT device to create three groups: the Control group, the Gutta-Percha group and the Bioceramic Gutta-Percha group. Two types of analysis were executed: an objective one, using the Region of Interest (ROI) to measure the pixel density of each tooth, and a subjective one, to compare the groups’ images. For the statistical analysis, Student’s t-test, descriptive statistics and the frequency distribution analysis were used for both objective and subjective analyses. Results: The agreement between the observers ranged from moderate to excellent. Similar grayscale values were obtained in both the GP and BCGP groups. These results were endorsed by the p-values obtained with Student’s t test. For the subjective analysis, the observers indicated the BCGP group as the one that developed the highest number of artifacts. Conclusions: Both materials produced artifacts in the CBCT images. However, in the subjective analysis, the BCGP group showed higher levels of artifact production than the GP group, which could result in the misdiagnosis of root fracture and in a worse prognosis for that tooth.Objetos metálicos, tais como retentores intrarradiculares e restaurações, podem produzir interferência grave, assim, diminuindo a qualidade de imagem TCFC (Tomografia Computadorizada de Feixe Cônico). Objetivo: o propósito deste estudo foi analisar a influência de cones de guta-percha convencionais e de biocerâmica na produção de artefatos nas imagens TCFC. Métodos: um dente pré-molar unirradicular extraído (n=20) foi instrumentalizado e escaneado com aparelho TCFC criando três grupos: o grupo Controle (C), o grupo Guta-Percha (GP) e o grupo Guta-Percha de Biocerâmica (GPB). Foram executados dois tipos de análises: uma objetiva, usando a Região de Interesse (ROI) para medir a densidade de pixels de cada dente; e uma subjetiva, para comparar as imagens dos grupos. Para a análise estatística, o teste t de Student, estatística descritiva e a análise de distribuição de frequência foram usadas tanto para a análise objetiva quanta para a subjetiva. Resultados: a concordância entre os observadores se deu entre moderado e excelente. Foram obtidos valores de escalas de cinza semelhantes no grupo GP e no grupo GPB. Tais resultados foram reforçados pelos valores-p obtidos pelo teste t de Student. Para a análise subjetiva, os observadores indicaram o grupo GPB como o que desenvolveu o maior número de artefatos. Conclusões: ambos os materiais produziram artefatos nas imagens TCFC. Entretanto, na análise subjetiva, o grupo GPB mostrou níveis maiores de produção de artefatos do que o grupo GP, o qual poderia resultar em um diagnóstico incorreto de fratura da raiz e em um prognóstico pior para aquele dente

Peri-orbital bone dimensional analysis using computed tomography for placement of osseointegrated implants

Craniofacial osseointegrated implants enabled producing implant-retained facial prosthesis, namely the orbital prosthesis. Aim: To evaluate the length and width of the bone structure of the peri-orbital region and to present the method validation. Methods: Computed tomography scans of 30 dry human skulls were obtained in order to register linear length and width measurements of the periorbital region. Two examiners made the measurements twice with intervals of at least 7 days between them. Data were analyzed by descriptive statistics and the paired Student's t-test was used as inferential technique (SAS, α =0.05). Results: In most cases, the intra- and inter-examiner variations were not significant (p>0.05). Therefore, the method proposed was considered as precise and valid for the measurement of the peri-orbital region. The measured points correspond to the hours of a clock. The major lengths were observed at 1 h (18.32 mm) for the left peri-orbital bone and at 11h (19.28 mm) for the right peri-orbital bone, followed by the points situated at 2h (13.05 mm) and 12h (11.37 mm) for the left side and at 10 h (12.34 mm) and 12 h (11.56 mm) for the right side. It was verified that the three points with lowest values followed the same anatomical sequence in the supraorbital rim for the right and left orbits, showing compatibility with the insertion of the intraoral osseointegrated implants. The medial wall of both orbits did not present sufficient length to allow the insertion of intraoral or craniofacial implants. Conclusions: The largest width points were observed in the supraorbital rim and in the infralateral region of both orbits and those of smallest width were found in the supralateral region of both orbits

Peri-orbital bone dimensional analysis using computed tomography for placement of osseointegrated implants

Craniofacial osseointegrated implants enabled producing implant-retained facial prosthesis, namely the orbital prosthesis. Aim: To evaluate the length and width of the bone structure of the peri-orbital region and to present the method validation. Methods: Computed tomography scans of 30 dry human skulls were obtained in order to register linear length and width measurements of the periorbital region. Two examiners made the measurements twice with intervals of at least 7 days between them. Data were analyzed by descriptive statistics and the paired Student’s t-test was used as inferential technique (SAS, α=0.05). Results: In most cases, the intra- and inter-examiner variations were not significant (p>0.05). Therefore, the method proposed was considered as precise and valid for the measurement of the peri-orbital region. The measured points correspond to the hours of a clock. The major lengths were observed at 1 h (18.32 mm) for the left peri-orbital bone and at 11h (19.28 mm) for the right peri-orbital bone, followed by the points situated at 2h (13.05 mm) and 12h (11.37 mm) for the left side and at 10 h (12.34 mm) and 12 h (11.56 mm) for the right side. It was verified that the three points with lowest values followed the same anatomical sequence in the supraorbital rim for the right and left orbits, showing compatibility with the insertion of the intraoral osseointegrated implants. The medial wall of both orbits did not present sufficient length to allow the insertion of intraoral or craniofacial implants. Conclusions: The largest width points were observed in the supraorbital rim and in the infralateral region of both orbits and those of smallest width were found in the supralateral region of both orbits

Peri-orbital bone dimensional analysis using computed tomography for placement of osseointegrated implants

acial osseointegrated implants enabled producing implant-retained facial prosthesis, namely the orbital prosthesis. Aim: To evaluate the length and width of the bone structure of the peri-orbital region and to present the method validation. Methods: Computed tomography scans of 30 dry human skulls were obtained in order to register linear length and width measurements of the periorbital region. Two examiners made the measurements twice with intervals of at least 7 days between them. Data were analyzed by descriptive statistics and the paired Students t-test was used as inferential technique (SAS, &#945;=0.05). Results: In most cases, the intra- and inter-examiner variations were not significant (p>0.05). Therefore, the method proposed was considered as precise and valid for the measurement of the peri-orbital region. The measured points correspond to the hours of a clock. The major lengths were observed at 1 h (18.32 mm) for the left peri-orbital bone and at 11h (19.28 mm) for the right peri-orbital bone, followed by the points situated at 2h (13.05 mm) and 12h (11.37 mm) for the left side and at 10 h (12.34 mm) and 12 h (11.56 mm) for the right side. It was verified that the three points with lowest values followed the same anatomical sequence in the supraorbital rim for the right and left orbits, showing compatibility with the insertion of the intraoral osseointegrated implants. The medial wall of both orbits did not present sufficient length to allow the insertion of intraoral or craniofacial implants. Conclusions: The largest width points were observed in the supraorbital rim and in the infralateral region of both orbits and those of smallest width were found in the supralateral region of both orbits