Nanostructured SBA-15 silica: An effective protective vehicle to oral hepatitis B vaccine immunization.

Due to its physicochemical properties, nanostructured mesoporous SBA-15 silica shows great potential as a vaccine adjuvant. This study evaluated the capacity of SBA-15 to encapsulate/adsorb the recombinant purified HBsAg from the Hepatitis B virus and the immunoresponsiveness of mice orally immunized with HBsAg inside SBA-15. A simulation of small angle X-ray scattering experimental results, together with the nitrogen adsorption isotherms data, allowed to determine the appropriate mass ratio of HBsAg:SBA-15, indicating antigen encapsulation into SBA-15 macroporosity. This was also evaluated by bicinchoninic acid assay and gel electrophoresis. The recruitment of inflammatory cells, an increase in production of specific antibodies, and the non-influence of silica on TH1 or TH2 polarization were observed after oral immunization. Besides, SBA-15 enhanced the phagocytosis of ovalbumin by dendritic cells, an important key to prove how this adjuvant works. Thus, it seems clear that the nanostructured SBA-15 is an effective and safe adjuvant for oral immunizations.

Effect of increased dwell times for solvent evaporation on the bond strength and degree of conversion of an ethanol-based adhesive system.

This study evaluated the influence of the prolonged setting time of an ethanol-based adhesive system on the dentin bond strength and degree of conversion. Labial and lingual surfaces of fifteen human third molars were flattened until the dentin was exposed and randomly allocated to 3 groups (n = 10), according to the dwell time between the application of two consecutive layers of the adhesive system (Adper Single Bond Plus, 3M ESPE) and light activation: G1--control (no extra dwell time); G2 and G3--dwell time of 30 seconds and 60 seconds, respectively. After light curing, two cylinders (1.4 x 1 mm) of composite resin (Filtek Flow, 3M ESPE) were bonded to each surface and submitted to micro-shear testing, 24 hours after light curing. A similar adhesive procedure was used for the degree of conversion evaluation using Fourier transform infrared spectroscopy (FTIR). Significant differences between bond strength values (p = 0.0003) and degrees of conversion (p = 0.0004) were detected. The bond strength of G3 (60-second dwell time) was statistically higher than that of other groups. G1 (control) and G2 (30-second dwell time) presented similar results. Values of degree of conversion indicated that both the 30-second and 60-second dwell times resulted in similar and greater percentages of conversion. The use of a longer dwell time (60 seconds) might provide better solvent volatilization and monomer infiltration; bringing benefits to dentin bonding using simplified etch & rinse adhesive systems.

The association between postmenopausal osteoporosis and periodontal disease.

BACKGROUND: The clinical importance of systemic bone loss as a contributory factor to alveolar bone loss and the subsequent loss of teeth merits further study, given that osteoporosis and periodontal disease lead to significantly increased morbidity and mortality and higher public expenditure of funds. This case-control study evaluated the association between osteoporosis and periodontal disease. METHODS: The sample consisted of 139 postmenopausal women: 48 in the case group (with periodontal disease) and 91 in the control group (without periodontal disease). The diagnosis of periodontal disease was established following a complete clinical examination using measurements of probing depth, gingival recession and hyperplasia, clinical attachment loss, and bleeding index, and confirmed by panoramic radiography. The diagnosis of osteoporosis was made by reviewing densitometry reports obtained previously. Descriptive, stratified, and logistic regression analyses were applied to the data collected. Comparison of proportions was performed using the chi(2) and Fisher tests. Association measurements (odds ratios [ORs]) with and without adjustment for confounding factors and control for effect modifiers were obtained at a significance level of 5%. RESULTS: The OR(unadjusted) for the principal association was 2.58 (95% confidence interval [CI]: 1.01 to 6.82). In subgroup analyses of the stratified model, the OR(unadjusted) for low education was 6.40 (95% CI: 1.77 to 23.18). When adjusted for smoking habit and age, the OR(adjusted) was 7.05 (95% CI: 1.90 to 26.19), which also was statistically significant. CONCLUSION: Postmenopausal women with osteoporosis and low educational levels have a greater chance of having periodontal disease than do those without osteoporosis.