Perimplantar bone repair in rabbit after LLLT: steriology and sem

Estudos prévios sugerem que a laserterapia de baixa potência (LLLT) favorece o reparo ósseo perimplantar. Este estudo avaliou a influência da LLLT sobre o reparo ósseo perimplantar in vivo em 32 coelhos Nova Zelândia submetidos à exodontia do incisivo inferior esquerdo imediatamente seguida pela inserção de um implante osseointegrável. Os animais foram distribuídos aleatoriamente em quatro grupos: um grupo controle C (animais não irradiados) e três experimentais. Estes receberam 7 sessões de terapia laser (AsGaAl, infravermelho, 830 ηm, 50mW, CW), com intervalos de 48 horas. A dose de laser por sessão variou entre os grupos EI (10 J/cm²), EII (5 J/cm²) e EIII (20J/cm²). Os animais foram mortos e os espécimes preparados histologicamente para análise da superfície de contato entre osso e implante (BIC) e da área de neoformação óssea entre as espiras (BA), em esteriologia e Microscopia Eletrônica de Varredura (MEV). A concentração de cálcio na interface do tecido ósseo com o implante foi analisada por espectrometria de raios-X por dispersão de energia (EDS). Os resultados foram analisados estatisticamente. Para MEV, as médias de BIC foram significativamente maiores para os grupos EI (977,9 μm) e EIII (1021,1 μm), comparados a EII (761,5 μm) e C (807,8 μm). Em BA, EIII (122573,7 μm²) superou os valores de neoformação dos demais grupos. O EDS para concentração de cálcio não apresentou diferença entre os grupos. A análise de BIC por meio de esteriologia mostrou valores significativamente maiores para EIII (1045,3 μm) em relação aos demais grupos. Para a BA, os grupos EI (100068,3 μm²) e EIII (103934,5 μm²) mostraram grandezas significativamente maiores. O uso da LLLT, no protocolo descrito, influenciou positivamente o reparo ósseo perimplantar com aumento do contato do tecido ósseo com o implante principalmente na dose de 20 J/cm² por sessão, bem como maior volume ósseo neoformado entre as espiras.Previous studies suggest that the low level laser therapy (LLLT) has a favorable effect on perimplant bone healing. This study evaluates the LLLT influence over perimplant bone healing pattern in 32 New Zealand male rabbits which were subimitted to a lower incisor extraction followed by an osseointegrated implant immediated insertion. The animals were randomly divided into four groups of eight animals each: a control group C (non-irradiated animal) and three experimental groups. They received seven laser therapy sessions (GaAlAs, infrared, 830 nm, 50 mW, CW), every 48 hours. The LLLT per session dose ranged between the groups EI (dose – 10 J/cm²), EII (dose – 5 J/cm²) and EIII (dose – 20 J/cm²). The animals were killed and the specimens received histological preparation for bone implant contact analysis (BIC) and Bone Area evaluation (BA) among the implant threads, both steriology and Scanning Electron Microscopy (SEM). The calcium concentration in bone implant interface were analysed by Energy-Disperse X-Ray Spectroscopy (EDS). The results were statistically analyzed. For SEM results, the BIC’s mean were significantly higher for the irradiated groups EI (977,9 μm) and EIII (1021,1 μm) compared to EII (761,5 μm) and C (807,8 μm). For BA, EIII (122573,7 μm²) showed better values for bone neoformation compared to other groups. For EDS calcium concentration there was no significantly difference between groups. The steriology analysis showed significantly higher values for BIC in EIII (1045,3 μm) compared to the other groups. For BA, EI (100068,3 μm²) and EIII (103934,5 μm²) were significantly higher. In this laser protocol, the use of LLLT induced positively perimplantar bone repair specially due to the bone implant contact improvement (20 J/cm² per session dose), as well as, better bone area neoformation within treads

Infecções odontogênicas : complicações severas associadas à diabetes mellitus

Objective: Ludwig’s angina is a severe form of diffuse cellulitis occurring in the cervicofacial region, with aggressive characteristics that systemically affect the patient and can lead to death. Disease severity is due to the formation of extensive laryngeal cellulitis, which evolves to edema of the glottis and consequently acute respiratory obstruction. The rapid progression of infection and the establishment of a severe general medical condition requires fast diagnosis and adequate management in order to improve prognosis. Case Report: This paper describes two cases of Ludwig’s angina in patients with diabetes mellitus treated at public hospitals in southern Brazil, with a focus on clinical characteristics, disease evolution, and treatment. Conclusion: Depending on the patient’s systemic conditions and the kind of established treatment, it may guide the diseased prognosis. One of the patients had a favorable outcome, whereas the other developed mediastinitis and died.Objetivo: A angina de Ludwig é uma das formas mais graves de celulite difusa da região cervicofacial, apresentando características agressivas que comprometem sistemicamente o paciente, podendo levá-lo ao óbito. Isso ocorre devido à intensa celulite na região de laringe, podendo evoluir para um edema de glote, com consequente obstrução respiratória aguda. Sua disseminação ainda pode ter um trajeto descendente envolvendo estruturas torácicas, caracterizando uma mediastinite. Esta agressividade na evolução do processo infeccioso e no estabelecimento de uma condição geral grave exige um diagnóstico rápido e uma conduta adequada visando favorecer o prognóstico. Relato de Caso: Este trabalho apresenta dois casos de Angina de Ludwig, em pacientes com Diabetes Melittus, atendidos em dois hospitais do Rio Grande do Sul, Brasil, analisando as características clínicas, bem como a evolução da doença e a terapêutica utilizada para cada caso. Conclusão: Dependendo da condição clínica do paciente, assim como, do tratamento de escolha utilizado, favorecerá ou não o prognóstico do paciente. Verificou-se um resultado favorável com a cura do paciente e o outro evoluiu para medistinite e óbito

Revista de Ciências Médicas e Biológicas

Abstract Objective: results of preclinical studies depend on high-quality sample preparation, which enables proper handling of specimens for observation and analysis with the desired methods. The aim of this paper is to describe a step-by-step method for preparation of bone tissue specimens containing metallic implants for scanning electron microscopy (SEM). Methodology: eight rabbit bone specimens containing one osseointegrated implant each were fixated in 10% neutral buffered formalin, dehydrated, sectioned, and embedded in thermosetting resin. The specimens were then sanded, polished, and metal-coated for SEM analysis. Results: the method achieved satisfactory specimen surface smoothness, containing no cracks or other artifacts, enabling morphological and chemical analysis by means of SEM and energy-dispersive X-ray spectroscopy (EDS). Conclusion: this method for preparation of animal tissue samples containing both organic and metal components produced specimens amenable to SEM analysis with excellent image quality, enabling assessment of the bone–implant interface, measurement of bone–implant contact, and quantification of bone formation. Key-words: Dental Implants. Microscopy Electron Scanning. Methodology. Dentistry.Objetivo: o resultado das pesquisas pré-clínicas dependem da elevada qualidade de preparo amostral, possibilitando um adequado manejo das peças para a observação nos mais diversos tipos de metodologia. O objetivo foi apresentar detalhadamente um método diferenciado para preparo de amostras de tecido-ósseo contendo implantes metálicos para Microscopia Eletrônica de Varredura, apresentando os passos para obtenção das peças. Metodologia: oito peças ósseas de modelo experimental coelho contendo um implante osseointegrável foram fixadas por 72 horas em formol 10% neutro tamponado. A seguir, procedeu-se sua secagem, corte e inclusão em resina termopolimerizável. Posteriormente, realizou-se um processo de lixamento sequencial, polimento e metalização para avaliação por meio de MEV. Resultados: as superfícies obtidas por meio desta metodologia demonstraram lisura superficial e ausência de trincas ou outros artefatos. Permitiu análise morfológica e química por meio de MEV/EDS. Conclusão: por meio desta metodologia, obteve-se amostras contendo componente orgânico e metálico, passíveis de análise por MEV em modelo experimental animal, com grande qualidade de imagem para estudo da interface osso-implante, medição do contato entre estas superfícies e avaliação da área de neoformação óssea.Salvado

Histomorphometric assessment of the influence of low-level laser therapy on peri-implant tissue healing in the rabbit mandible

Objective: The purpose of this study was to demonstrate the effect of low-level laser therapy (LLLT) on the peri-implant bone healing process in the rabbit mandible. Background data: LLLT has been shown to accelerate tissue repair and osseointegration of implants placed into the rabbit tibia. However, the beneficial effects of LLLT have never been tested in the rabbit mandible, which would more closely mimic the human situation. Materials and methods: Twenty-four male New Zealand rabbits were randomly divided into four groups of six animals each. All animals had their left mandibular incisors extracted, followed by immediate insertion of a titanium dental implant in the fresh socket. Three groups received LLLT [aluminum-galliumarsenide (AlGaAs), λ=830nm, 50mW, continuous wave (CW)] at three different energy densities per treatment session (E-5, 5 J/cm²; E-10, 10 J/cm2; and E-20, 20 J/cm²). Irradiation was performed every 48 h for 13 days, totaling seven sessions. One group received sham treatment (controls). Histological sections were obtained from each of the 24 mandibles dissected, without first decalcifying the specimens, and were stained with hematoxylin and eosin and Picrosirius red for histomorphometric evaluation. Bone-to-implant contact (BIC), bone formation area, and collagen fiber area were assessed by light microscopy. Results: Significant differences were found between group E-20 and all other groups ( p < 0.05). Histomorphometric evaluation showed significantly higher BIC and significantly more collagen fibers in group E-20. Conclusions: Photobiostimulation with LLLT at an energy density of 20 J/cm2 per session had a significant positive effect on new bone formation around dental implants inserted in the rabbit mandible

Preparation of biological samples containing both metallic and organic structures for SEM

Objective: results of preclinical studies depend on high-quality sample preparation, which enables proper handling of specimens for observation and analysis with the desired methods. The aim of this paper is to describe a step-by-step method for preparation of bone tissue specimens containing metallic implants for scanning electron microscopy (SEM). Methodology: eight rabbit bone specimens containing one osseointegrated implant each were fixated in 10% neutral buffered formalin, dehydrated, sectioned, and embeddedin thermosetting resin. The specimens were then sanded, polished, and metal-coated for SEM analysis. Results: the method achieved satisfactory specimen surface smoothness, containing no cracks or other artifacts, enabling morphological and chemical analysis by means of SEM and energy-dispersive X-ray spectroscopy (EDS). Conclusion: this method for preparation of animal tissue samplescontaining both organic and metal components produced specimens amenable to SEM analysis with excellent image quality, enabling assessment of the bone–implant interface, measurement of bone–implant contact, and quantification of bone formation