Intraoral radiographs texture analysis for dental implant planning.

BACKGROUND AND OBJECTIVES: Computer vision extracts features or attributes from images improving diagnosis accuracy and aiding in clinical decisions. This study aims to investigate the feasibility of using texture analysis of periapical radiograph images as a tool for dental implant treatment planning. METHODS: Periapical radiograph images of 127 jawbone sites were obtained before and after implant placement. From the superimposition of the pre- and post-implant images, four regions of interest (ROI) were delineated on the pre-implant images for each implant site: mesial, distal and apical peri-implant areas and a central area. Each ROI was analysed using Matlab® software and seven image attributes were extracted: mean grey level (MGL), standard deviation of grey levels (SDGL), coefficient of variation (CV), entropy (En), contrast, correlation (Cor) and angular second moment (ASM). Images were grouped by bone types-Lekholm and Zarb classification (1,2,3,4). Peak insertion torque (PIT) and resonance frequency analysis (RFA) were recorded during implant placement. Differences among groups were tested for each image attribute. Agreement between measurements of the peri-implant ROIs and overall ROI (peri-implant + central area) was tested, as well as the association between primary stability measures (PIT and RFA) and texture attributes. RESULTS: Differences among bone type groups were found for MGL (p = 0.035), SDGL (p = 0.024), CV (p < 0.001) and En (p < 0.001). The apical ROI showed a significant difference from the other regions for all attributes, except Cor. Concordance correlation coefficients were all almost perfect (ρ > 0.93), except for ASM (ρ = 0.62). Texture attributes were significantly associated with the implant stability measures. CONCLUSION: Texture analysis of periapical radiographs may be a reliable non-invasive quantitative method for the assessment of jawbone and prediction of implant stability, with potential clinical applications.

Activity of bristles from an Amazonian lepidoptera, "Premolis semirufa", on the human complement system

O lepidóptero Premolis semirufa habita os seringais da regiao Amazônica. Os seringueiros denominam pararama a forma larval do inseto e pararamose a doença ocupacional causada pelo contato acidental com cerdas da larva ou casulo durante a coleta do látex. Os sintomas imediatos que se seguem ao contato sao locais e consistem em prurido intenso, edema e dor, que sao geralmente transitórios e desaparecem em poucos dias. Entretanto, em algumas circunstâncias, o processo torna-se crônico, podendo evoluir para a deformidade e imobilizaçao da articulaçao afetada, lembrando, sob alguns aspectos, artrite reumatóide. O estudo da açao in vitro de cerdas e substâncias solúveis associadas sobre o sistema complemento humano mostrou que tanto cerdas quanto extrato salino inativam complemento total e o componente C2, geram C3d a partir de C3, sem afetar os níveis de Clq. Estes resultados sugerem que a via clássica de ativaçao do complemento nao está envolvida no processo. A inativaçao direta de C2 e a geraçao de C3d sao compatíveis com a presença de substâncias solúveis com açao lítica associadas às cerdas, embora nao tenha sido excluída ativaçao paralela da via alternativa como mecanismo de produçao de C3d