Percorrer por autor "Chaves, Carolina"
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- Functional monomer type determines the interfacial properties of experimental self-adhesive composites bonded to dentinPublication . Andrade, Rita; Chaves, Carolina; Silva, Diana C.; Serro, Ana Paula; Azul, Ana Mano; Águas, Hugo; Delgado, António H. S.Purpose: To evaluate the influence of functional monomer type and powder-to-liquid ratio on the interfacial properties and degree of conversion of experimental self-adhesive flowable resin composites (SAFRCs) bonded to dentin. Materials and Methods: Nine experimental SAFRC formulations were developed by varying the powder-to-liquid ratio (1.9, 2.2, 2.5) and the functional monomers included (10-MDP, GPDM, HEMA). Human molars (n = 27) were restored using each formulation and analyzed using a rheometer to assess viscosity, Raman micro-spectroscopy for inter-diffusion zone (IDZ) width, and degree of conversion at the interface (DC%). Two-way ANOVA and post-hoc tests were performed for statistical analysis (α = 0.05). Results: Rheological testing revealed, as expected, non-Newtonian flow behavior in all composites, with significant effects of both powder-to-liquid ratio (P 0.001) and monomer type (P 0.001) on viscosity. 10-MDP composites exhibited optimal viscosity (1.12–2.86 mPa·s) across all ratios, significantly lower than GPDM and HEMA. Raman mapping showed a distinct IDZ with hybrid characteristics for 10-MDP formulations, contrasting with abrupt transitions or gaps in GPDM and HEMA groups. IDZ width was significantly greater in 10-MDP formulations (P 0.0001). The DC% at the interface was highest for 10-MDP and HEMA formulations, exceeding 68%, while GPDM composites showed lower values (P 0.001). Conclusion: Functional monomer type critically affects the interfacial bonding performance and conversion rate of SAFRCs, with 10-MDP outperforming GPDM and HEMA in interdiffusion and adhesive quality. Variations in powder-to-liquid ratio influenced viscosity but had a limited impact on interfacial performance. Optimized formulations with 10-MDP may enhance the clinical efficacy of SAFRCs. Clinical Relevance Statement: Refining acidic-monomer chemistry and viscosity in SAFRCs could improve their bonding predictability.
- Niobium-based conditioning layer to reduce bacterial adhesion and biofilm formation on titanium surfacePublication . Oliveira, Viviane C.; Magalhães, Nilza L.; Maciel, Carla R. O.; Silva, André F. A. S.; Bim, Lucas L.; Chaves, Carolina; Nascimento, Cássio do; Paula-Silva, Francisco W.; Silva-Lovato, Cláudia H.; Ramos, Ana P.; Ferreira, Adriano M.; Watanabe, EvandroNiobium metal has a wide range of applications; however, the development of Nb-coated surfaces with antimicrobial activity remains unexplored. This study investigates the antimicrobial and antibiofilm activities of ammoniacal niobium oxalate (ANO) and develops a methodology to deposit it on titanium-functionalized surfaces to prevent bacterial colonization and biofilm formation. ANO is dispersed in water and characterized for particle size, Fourier transform infrared spectroscopy, X-ray diffraction, ζ-potential, and in vitro cytotoxicity. Its antimicrobial activity is assessed by microdilution and inhibition halo assays against Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, and Candida glabrata. Antibiofilm activity is evaluated through biomass quantification, respiratory activity, and morphological analysis. Titanium surfaces functionalized with polyacrylic-acid–ANO films are tested under dynamic flow conditions for their antifouling properties in a multispecies biofilm model. ANO particles (∼450 nm) exhibit a negative charge, high crystallinity, and low cytotoxicity. The compound inhibits both Gram-negative and Gram-positive bacteria, even at low concentrations, and reduces the metabolic activity of mature biofilms. However, it does not remove aggregates or prevent adhesion and biofilm growth on titanium surfaces, indicating the need for further optimization of the functionalization conditions.