ABSTRACT
INTRODUCTION: The aim of this study was to evaluate the radiopacity of calcium aluminate cement (EndoBinder) with 3 different radiopacifiers (bismuth oxide, zinc oxide, or zirconium oxide) in comparison with gray mineral trioxide aggregate (GMTA), white MTA, and dental structures (enamel and dentin). METHODS: Eighteen test specimens of each cement with thicknesses of 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mm (n = 3) were made by using a stainless steel matrix and were adapted to a standardizing device (8 × 7 cm) with a graduated aluminum stepwedge varying from 2.0-16.0 mm in thickness. To compare the radiopacity of the cements with that of dental structures, slices of first molars with a thickness increasing from 0.5-3.0 mm were obtained and placed on the standardizing device. One occlusal radiograph for each tested cement was taken, with exposure time of 0.1 seconds and focus-film distance of 20 cm. Films were processed in an automatic device, and the mean radiopacity values were obtained by using a photodensitometer. RESULTS: Mean values showed that the thicker the specimen was, the greater was its radiopacity. Only EndoBinder + bismuth oxide (EBBO) and GMTA demonstrated radiopacity values greater than 3.0 mm of the aluminum scale for all thicknesses. When zinc oxide was used as radiopacifier agent, EndoBinder only reached the desired radiopacity with a thickness of 2.0 mm, and with zirconium oxide it was 2.5 mm. CONCLUSIONS: Bismuth oxide was the most efficient radiopacifier for EndoBinder, providing adequate radiopacity in all studied thicknesses, as recommended by ISO 6876, being similar to GMTA.
Subject(s)
Aluminum Compounds/chemistry , Calcium Compounds/chemistry , Contrast Media/chemistry , Dental Cements/chemistry , Dental Enamel/diagnostic imaging , Dentin/diagnostic imaging , Root Canal Filling Materials/chemistry , Aluminum Compounds/radiation effects , Bismuth/chemistry , Calcium Compounds/radiation effects , Contrast Media/radiation effects , Dental Cements/radiation effects , Glutamates/chemistry , Glutamates/radiation effects , Guanine/analogs & derivatives , Guanine/chemistry , Guanine/radiation effects , Humans , Pemetrexed , Radiography, Dental , Root Canal Filling Materials/radiation effects , Zinc Oxide/chemistry , Zirconium/chemistryABSTRACT
OBJETIVO: O presente estudo consistiu em investigar a influência da radiação ionizante por raios X e raios gama sobre a estabilidade molecular de diversos meios de contraste radiológicos utilizados em exames de diagnóstico por imagem, por meio da espectroscopia de ressonância magnética nuclear de ÕH e 13C. MATERIAIS E MÉTODOS: Oito diferentes meios de contraste iodados (três iônicos e cinco não iônicos) foram expostos à radiação por raios X e raios gama. Em seguida, espectros de ressonância magnética nuclear de ÕH e 13C{ÕH} foram coletados. RESULTADOS: Os espectros de ressonância magnética nuclear de 13C{ÕH} de ambos os meios de contraste iônicos e não iônicos irradiados por raios X ou raios gama mostraram que não houve alterações na composição química desses contrastes. CONCLUSÃO: Não há problemas em armazenar as amostras nas salas, ou próximo aos equipamentos em que são realizados os exames. Enfatiza-se que a radiação recebida pelas amostras durante os ensaios foi direta, enquanto em uma sala de exames de radiodiagnóstico a radiação é indireta e, portanto, os níveis de radiações nestes casos são bastante inferiores àqueles empregados neste estudo.
OBJECTIVE: The purpose of the present study was to investigate the influence of ionizing radiation from x-rays and gamma rays on the molecular structure stability of several radiologic contrast media employed in diagnostic imaging by means of ÕH and 13C nuclear magnetic resonance spectroscopy. MATERIALS AND METHODS: Eight different types of iodinated contrast media (three ionic and five non-ionic) were exposed to x-rays and gamma rays irradiation. Subsequently, the ÕH and 13C{ÕH} nuclear magnetic resonance spectra of these contrast media were collected. RESULTS: The ÕH and 13C{ÕH} nuclear magnetic resonance spectra of both ionic and non-ionic contrast media irradiated by x-rays or gamma rays demonstrated the absence of any alteration of the contrast media chemical composition. CONCLUSION: There is no problem in keeping contrast media inside examination rooms or close to radiological equipment. It is important to mention that, during the tests, the samples were directly irradiated, while in a radiology examination room, the irradiation is not direct and, therefore, radiation levels in these cases are much lower than those employed in the present study.
Subject(s)
Humans , Diagnostic Imaging/methods , Gamma Rays , Magnetic Resonance Spectroscopy , Contrast Media/analysis , Contrast Media/radiation effects , Radiation, Ionizing , X-RaysABSTRACT
The aim of this study was to evaluate the effect of radiotherapy on the radiopacity and flexural strength of composite resin. Forty Z250 composite resin specimens were polymerized using a halogen light-curing unit and divided into 5 groups, in accordance with the radiotherapy dose: G1- without irradiation, G2- 30 Gy, G3- 40 Gy, G4- 50 Gy and GS- 60 Gy Digital images were obtained using a GE 100 X-ray. Radiopacity values were obtained with the Digora digital imaging system and the flexural strength was evaluated with an EMIC universal testing machine. Data were submitted to ANOVA and Tukey 's test. G1 presented the highest radiopacity value, followed by G3, G5, G4 and G2. For flexural strength, G1 presented the lowest value, followed by G2, G5, G3 and G4. Differences were no significant (p>0.05). The commonly used dosage of radiotherapy treatment, did not cause alteration in the radiopacity and flexural strength of resin-based composites.
Subject(s)
Composite Resins/radiation effects , Dental Materials/radiation effects , Radiotherapy , Absorptiometry, Photon , Composite Resins/chemistry , Contrast Media/chemistry , Contrast Media/radiation effects , Curing Lights, Dental , Dental Materials/chemistry , Dental Stress Analysis/instrumentation , Humans , Materials Testing , Pliability , Polymers/chemistry , Polymers/radiation effects , Radiography, Dental, Digital/instrumentation , Radiotherapy Dosage , Stress, MechanicalABSTRACT
Resumo: A demanda para exames baritados de duplo contraste como primeira linha de investigação em pacientes com dispepsia está diminuindo. Muitos profissionais defendem que se trata de um exame menos sensível que a endoscopia e que, nos casos em que se detecta uma lesãosuspeita o paciente é encaminhado para a realização de exame endoscópico para confirmação, o que retardaria o diagnóstico. Não obstante, os exames contrastados permanecem como popular primeira linha de investigação, especialmente para os pacientes jovens dispépticos. Tanto os exames endoscópicos como os contrastados apresentam vantagens e desvantagens, que devem ser consideradas de forma singular de um caso para o outro. Considerando o menor custo e a inespecificidade de muitas das queixas gastrointestinais, acreditamos que os exames contrastados do trato digestivo alto são sempre uma possobilidade a ser considerada entre os diversos exames complementares.
Subject(s)
Humans , Contrast Media/radiation effects , Contrast Sensitivity , Gastrointestinal Contents , RadiographyABSTRACT
Este trabalho apresenta um estudo comparativo de dois métodos de substração de angiografias determinando as vantagens e desvantagens de cada um em relação ao ruido das imagens.