This study conducted a systematic review to assess the bi-directional association between tooth loss/edentulism and obesity. Electronic searches were performed in four different databases. Observational studies that tested associations between tooth loss/edentulism and obesity as either exposures or outcomes were included. Additionally, meta-analyses, funnel plots and sensitivity analyses were conducted to synthesize the evidence. A total of 549 articles were identified in the electronic database search. Out of which, 16 studies were included within the meta-analyses: 75% considered tooth loss/edentulism as exposure and obesity as outcome, whereas 25% alternatively considered obesity as exposure and tooth loss/edentulism as outcome. Pooled estimates showed that obese individuals had 1.49 (95%CI 1.20-1.86) and 1.25 (95%CI 1.10-1.42) times higher odds of having any tooth loss and edentulism, respectively. Alternatively, when tooth loss or edentulism were considered as exposures, individuals with any tooth loss had 1.41 (95%CI 1.11-1.79) times higher odds for obesity, while edentates had even higher odds (OR 1.60; 95%CI 1.29-2.00). The results indicate a bi-directional association between tooth loss and obesity. Considering that all selected studies were of cross-sectional study design limiting inferences on temporality, longitudinal prospective studies are required to test the causal relationship between tooth loss/edentulism and obesity or vice a versa. © 2016 World Obesity.

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Scanning electron microscopy (SEM) is commonly used in the analysis of scaffolds morphology, as well as cell attachment, morphology and spreading on to the scaffolds. However, so far a specific methodology to prepare the alginate hydrogel (AH) scaffolds for SEM analysis has not been evaluated. This study compared different methods to fix/dehydrate cells in AH scaffolds for SEM analysis. AH scaffolds were prepared and seeded with NIH/3T3 cell line; fixed with glutaraldehyde, osmium tetroxide, or the freeze drying method and analyzed by SEM. Results demonstrated that the freeze dried method interferes less with cell morphology and density, and preserves the scaffolds structure. The fixation with glutaraldehyde did not affect cells morphology and density; however, the scaffolds morphology was affected in some level. The fixation with osmium tetroxide interfered in the natural structure of cells and scaffold. In conclusion the freeze drying and glutaraldehyde are suitable methods for cell fixation in AH scaffold for SEM, although scaffolds structure seems to be affected by glutaraldehyde.