Ultrastructural assessment of the radioprotective effects of sodium selenite on parotid glands in rats.

The aim of this study was to assess the radioprotective effects of sodium selenite on parotid glands in rats by ultrastructural analysis of acinar cells. Four experimental groups were assessed; control, irradiated, selenium, and selenium/irradiated. The sodium selenite dose was 0.5 mg/kg, administered intraperitoneally 24 h before irradiation in the head and neck region with a single 15-Gy dose of gamma radiation. At 4, 8, 12, 48 and 72 h after irradiation, all animals were sacrificed and the parotid glands were removed. Radiation caused cellular changes from 4 h, and the organelles that presented the greatest alterations were the mitochondria and the secretion glands; nuclear alterations were also observed. Sodium selenite was found to have a radioprotective action, as the selenium/irradiated group presented with less damage when compared to the irradiated group. However, sodium selenite caused cellular alterations that were evident after 8 h, but with less damage when compared to those caused by radiation, which demonstrates a favorable risk-benefit for its use as a radioprotector. Thus, this research shows that sodium selenite has an effective radioprotective action in the parotid gland, which may contribute to the reduction of the adverse effects brought by the radiotherapy.

Oral streptococci growth on aging and non-aging esthetic restorations after radiotherapy.

The aim of this study was to examine Streptococcus mutans biofilm growth on both aged and non-aged restorative dental resins, which were submitted to therapeutic irradiation. Sixty-four disks of an esthetic restorative material (Filtek Supreme) were divided into 2 groups: aged group (AG) and a non-aged group (NAG). Each group was subdivided into 4 subgroups: non-irradiated and irradiated with 10Gy, 35Gy, and 70Gy. The biofilms were produced by Streptococcus mutans UA159 growing on both AG and NAG surfaces. The colony-forming units per mL (CFU/mL) were evaluated by the ANOVA and the Tukey LSD tests (α=0.05). AG presented smaller amounts of CFU/mL than the NAG before irradiation and after 10Gy of irradiation (p<0.05). AG irradiated with 35 and 70Gy showed increased amount of bacterial biofilm when compared to non-irradiated and 10Gy-irradiated disks (p<0.05). The exposure to ionizing radiation at therapeutic doses promoted changes in bacterial adherence of aged dental restorative material.

Oral streptococci growth on aging and non-aging esthetic restorations after radiotherapy

The aim of this study was to examine Streptococcus mutans biofilm growth on both aged and non-aged restorative dental resins, which were submitted to therapeutic irradiation. Sixty-four disks of an esthetic restorative material (Filtek Supreme) were divided into 2 groups: aged group (AG) and a non-aged group (NAG). Each group was subdivided into 4 subgroups: non-irradiated and irradiated with 10Gy, 35Gy, and 70Gy. The biofilms were produced by Streptococcus mutans UA159 growing on both AG and NAG surfaces. The colony-forming units per mL (CFU/mL) were evaluated by the ANOVA and the Tukey LSD tests (α=0.05). AG presented smaller amounts of CFU/mL than the NAG before irradiation and after 10Gy of irradiation (p<0.05). AG irradiated with 35 and 70Gy showed increased amount of bacterial biofilm when compared to non-irradiated and 10Gy-irradiated disks (p<0.05). The exposure to ionizing radiation at therapeutic doses promoted changes in bacterial adherence of aged dental restorative material.

O objetivo deste estudo foi avaliar a formação do biofilme de Streptococcus mutans crescido em resina restauradora envelhecida e não-envelhecida, submetidas à radiação terapêutica. Sessenta e quatro discos do material restaurador Filtek Supreme foram divididos em 2 grupos: grupo envelhecido (AG) e grupo não-envelhecido (NAG) e cada grupo foi dividido em 4 sub-grupos: não-irradiado e irradiado com 10Gy, 35Gy e 70Gy. O biofilme de S. mutans UA159 foi produzido na superfície de ambos os discos AG e NAG. As unidades formadoras de colônia/mL (UFC/mL) foram avaliadas por ANOVA e teste de Tukey (α=0,05). O grupo AG demonstrou menores quantidades de UFC/mL que o grupo NAG antes da radiação e após a radiação de 10Gy (p<0,05). Os sub-grupos AG irradiados com 35 e 70Gy demonstraram aumento na quantidade de biofilme quando comparado aos não irradiados e irradiados com 10Gy (p<0,05). A exposição à radiação ionizante nas doses terapêuticas promoveu mudanças na aderência bacteriana no material restaurador.

Imaging findings of Ewing's sarcoma in the mandible.

First described by James Ewing in 1921, Ewing's sarcoma (ES) or Ewing's tumor is one of the most aggressive bone tumors known. ES is an uncommon intra-osseous malignant tumor of questionable pathogenesis that occurs in children and young adults. Reports indicate that only 2 to 7% of cases involve the maxillofacial region, usually the mandible ramus, and few reported cases have involved the maxilla. In the present report of a case of ES of the mandible, we describe the results of imaging and evaluation after therapeutic treatment. This report provides a rare opportunity to observe radiologic features of ES in the mandible.

As alterações radiográficas digitais efetuadas em programas gráficos são identificáveis? / Can manipulations on the digital radiographs using image processing softwares be recognizable?

As radiografias digitais, assim como as radiografias convencionais digitalizadas, podem facilmente ser modificadas por técnicas de processamento de imagens, tais como ajuste de contraste e brilho, realce de bordas, e outras, que contribuem para o aumento do seu potencial diagnóstico. Por outro lado, estas radiografias também podem ser manipuladas pela alteração, adição ou remoção de objetos na imagem. Para testar o potencial para uso fraudulento destas alterações, os autores alteratam uma série de radiografias digitais, utilizando programas de processamento de imagens, e submeteram estas à avaliação de 142 cirurgiões dentistas, que tentaram indentificá-las por meio do preenchimento de um questionário.