Effects of the unilateral removal and dissection of the masseter muscle on the facial growth of young rats

This study analyzed the effects of the unilateral removal and dissection of the masseter muscle on the facial growth of young rats. A total of 30 one-month-old Wistar rats were used. Unilateral complete removal of the masseter muscle was performed in the removal group, and detachment followed by repositioning of the masseter muscle was performed in the dissection group, while only surgical access was performed in the sham-operated group. The animals were sacrificed at three months of age. Axial radiographic projections of the skulls and lateral projections of the hemimandibles were taken. Cephalometric evaluations were made and the values obtained were submitted to statistical analyses. In the removal group, there were contour alterations of the angular process, and a significant homolateral difference in the length of the maxilla and a significant bilateral difference in the height of the mandibular body and the length of the mandible were observed. Comparison among groups revealed significance only in the removal group. It was concluded that the experimental removal of the masseter muscle during the growing period in rats induced atrophic changes in the angular process, as well as asymmetry of the maxilla and shortening of the whole mandible

Influência da manipulação na elasticidade de siliconas de adição em consistência de massa

The handling of vinyl polysiloxane (addition silicone) impression putties with latex gloves is said to interfere with the setting of these impression materials. The aim of this study is to evaluate the effect of handling techniques on the setting of vinyl polysiloxane impression putties using several types of gloves. The setting of these materials was evaluated by means of an elasticimeter. Four vinyl polysiloxane putty impression materials and five brands of gloves (one made of vinyl, one of synthetic rubber, and three of natural rubber) were studied. Based on the type of glove, they were previously washed or not, and a spatula was used or not for initial mixing (before handmixing). The vinyl, the synthetic and one of the natural rubber gloves did not require the previous washing procedure and/or the use of a spatula for initial mixing. Two other natural rubber gloves - depending on the silicone -, showed satisfactory results only when the initial mixing was performed with a spatula. It was concluded that setting inhibition depends on the kind of vinyl polysiloxane impression material and the kind of gloves used, but when the initial mixing was performed with the spatula this setting inhibition was overcome. The results of this study also showed that it is possible to associate cross-contamination control and satisfactory performance of addition silicone putty materials. When doubts arise from the compatibility between vinyl polysiloxane impression putties and gloves, the initial mixing should be performed with a spatula.A finalidade da presente pesquisa foi avaliar a influência na elasticidade da manipulação de silicones de adição em consistência de massa, por meio de várias técnicas, empregando-se luvas. A polimerização dos materiais foi avaliada por meio de um elasticímetro. Ensaiaram-se quatro silicones, empregando cinco marcas de luvas (uma de vinil, uma de borracha sintética e três de borracha natural). Dependendo do tipo de luva, ela foi lavada ou não e ainda foi utilizada ou não uma espátula para a mistura inicial dos silicones. Os resultados demonstraram que no emprego das luvas de vinil, uma das de borracha sintética e uma das de borracha natural não precisaram ser lavadas, nem a utilização de espátula para a mistura inicial foi necessária. Duas luvas de borracha natural não conduziram a resultados satisfatórios com todos os silicones sem que a mistura inicial fosse feita com a espátula mas, com essa prática, todas as luvas foram compatíveis com todos os silicones. Pode-se concluir que, em caso de dúvida sobre a compatibilidade entre tipo de luva e marca de silicone, o emprego de espátula na mistura inicial contorna o problema

Biological effects of ozone in water on dermal wound healing in rats

A ozonioterapia tem sido descrita como uma alternativa de tratamento para várias doenças por intervir possivelmente de forma favorável na reparação tecidual. A proposição desta pesquisa foi analisar os efeitos biológicos do ozônio diluído em água no processo de reparação tecidual, empregando duas concentrações diferentes. Foram realizadas feridas dérmicas padronizadas, com a utilização de punch, para excisão de fragmento da pele, com 5mm de diâmetro e profundidade, no dorso de 48 ratos. Os animais foram divididos em quatro grupos, conforme o tratamento realizado: em um grupo as feridas foram irrigadas com água ozonizada na concentração de 4ppm (GO3>), em outro foi utilizada água ozonizada na concentração de 1ppm (GO3 apresentou contração da ferida mais regular, com diferenças estatisticamente significantes em comparação aos outros grupos. No período inicial de observação, a análise histomorfológica revelou que os GO3> e GO3 e Gnada apresentaram de forma mais expressiva as características histológicas do tecido de granulação em formação, como expressão mais intensa de síntese de colágeno e formação de matriz colagênica mais organizada. As análises imunoistoquímicas revelaram que a marcação do colágeno tipo-I foi regular para todos os grupos, e que os grupos irrigados com água ozonizada apresentaram maior número de miofibroblastos. Provavelmente a capacidade do ozônio em interferir em reações bioquímicas celulares, bem como a maior quantidade de oxigênio proveniente da água ozonizada, podem estar relacionados aos eventos observados à reparação tecidual, que podem ser interpretados como favoráveis dependendo da situação clínica. Os resultados desta pesquisa sugeriram atuação do ozônio diluído em água na reparação das lesões teciduais, de forma dependente da dose, com possível favorecimento ao fechamento tecidual e provável estímulos inflamatórios e reparadores que favoreceram a síntese de tecido, sem produzir efeito tóxico ou prejudicial.The ozone therapy has been described as an alternative treatment for many diseases due to its action on tissue healing. The purpose of this research was to analyze the biological effects of ozonized water, in two different concentrations, on tissue healing. Standard dermical wounds were made with a punch to excise a skin fragment with 5 millimeters diameter and depth, in the back of 48 rats. The animals were divided in four groups according to treatment: in one group the wounds were irrigated with ozonized water at 4ppm (GO3>), in other group the wounds were irrigated with ozonized water at 1ppm (GO3 group showed more regular wound contraction; with statistically significant differences in comparison with the others groups. In the last period, the GO3> group showed a better shape factor (relation between area and perimeter) with statically significant differences in comparison to others groups. In the initial period of observation (2 days), the histomorphologic analysis revealed that the GO3> and GO3 e Gnoun showed more evident features of healing process, as such more intense expression of fibrils collagen and collagen matrix synthesis. The immunohistochemistry studies revealed that the collagen type-I scoring was regular for all groups and that the irrigated groups with ozonized water showed a higher number of miofibroblasts. Probably, the ozones capacity to interfere in biochemistry cellular reactions, as well the high oxygen quantity originated from ozonized water, may be related to tissue healing events, that may be favorable for some clinical situation. These results suggest that the ozonized water acts on tissue repair, in a dose dependent way, contributing to wound contraction and to tissue synthesis, without toxic effect