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Aims: To study the effect of adjunctive systemic administration of melatonin to standard mechanical periodontal therapy in obese rats with experimental periodontitis. Materials and methods: In 42 Wistar rats with an initial body weight of 180 g., half (n = 21) were fed with a high-fat diet to induce obesity. In both obese and normal-weight groups, experimental periodontitis was subsequently induced through oral gavages with a combination of Porphyromonas gingivalis and Fusobacterium nucleatum. Both groups were randomly allocated to either no treatment or periodontal treatment consisting on standard mechanical debridement, with either adjunctive chlorhexidine or melatonin. Outcomes were evaluated by the changes in clinical parameters (probing depth modified gingival index, plaque dental index and bleeding on probing [BOP]), in bone resorption and in the levels of biomarkers in plasma and in gingival tissue (inflammatory cytokines, insulin, leptin, osteocalcin, osteopontin, plasminogen activator inhibitor-1, intercellular adhesion molecule 1, E-selectin and lipids). Results: In the obese-periodontitis group, adjunctive melatonin administration resulted in reduced gingival inflammation and BOP, with significant reductions in probing depth and enhanced bone repair demonstrated by micro-CT (15% reduction in alveolar bone destruction) when compared with the same group treated with adjunctive CHX or the normal-weight rats with either melatonin or CHX. In this melatonin-treated obese-periodontitis group, a significant impact on biochemical biomarkers was also demonstrated in both gingival and plasma samples, when compared with the other groups, with significant reductions in pro-inflammatory cytokines. Conclusions: Adjunctive melatonin therapy significantly reduced alveolar bone loss and exerted a protective anti-inflammatory effect mainly in those experimental animals affected by the co-morbidity of periodontitis and obesity., Depto. de Especialidades Clínicas Odontológicas, Depto. de Bioquímica y Biología Molecular, Depto. de Biología Celular, Fac. de Odontología, Fac. de Medicina, TRUE, pub

Experimental dental resin composites containing copper-doped mesoporous bioactive glass nanospheres (Cu-MBGN) were developed to impart anti-bacterial properties. Increasing amounts of Cu-MBGN (0, 1, 5 and 10 wt%) were added to the BisGMA/TEGDMA resin matrix containing micro- and nano-fillers of inert glass, keeping the resin/filler ratio constant. Surface micromorphology and elemental analysis were performed to evaluate the homogeneous distribution of filler particles. The study investigated the effects of Cu-MBGN on the degree of conversion, polymerization shrinkage, porosity, ion release and anti-bacterial activity on S. mutans and A. naeslundii. Experimental materials containing Cu-MBGN showed a dose-dependent Cu release with an initial burst and a further increase after 28 days. The composite containing 10% Cu-MBGN had the best anti-bacterial effect on S. mutans, as evidenced by the lowest adherence of free-floating bacteria and biofilm formation. In contrast, the 45S5-containing materials had the highest S. mutans adherence. Ca release was highest in the bioactive control containing 15% 45S5, which correlated with the highest number of open porosities on the surface. Polymerization shrinkage was similar for all tested materials, ranging from 3.8 to 4.2%, while the degree of conversion was lower for Cu-MBGN materials. Cu-MBGN composites showed better anti-bacterial properties than composites with 45S5 BG.

We embedded copper-doped mesoporous bioactive glass nanospheres (Cu-MBGN) with antibacterial and ion-releasing properties into experimental dental composites and investigated the effect of Cu-MBGN on the polymerisation properties. We prepared seven composites with a BisGMA/TEGDMA (60/40) matrix and 65 wt.% total filler content, added Cu-MBGN or a combination of Cu-MBGN and silanised silica to the silanised barium glass base, and examined nine parameters: light transmittance, degree of conversion (DC), maximum polymerisation rate (Rmax), time to reach Rmax, linear shrinkage, shrinkage stress (PSS), maximum PSS rate, time to reach maximum PSS rate, and depth of cure. Cu-MBGN without silica accelerated polymerisation, reduced light transmission, and had the highest DC (58.8 ± 0.9%) and Rmax (9.8 ± 0.2%/s), but lower shrinkage (3 ± 0.05%) and similar PSS (0.89 ± 0.07 MPa) versus the inert reference (0.83 ± 0.13 MPa). Combined Cu-MBGN and silica slowed the Rmax and achieved a similar DC but resulted in higher shrinkage. However, using a combined 5 wt.% Cu-MBGN and silica, the PSS resembled that of the inert reference. The synergistic action of 5 wt.% Cu-MBGN and silanised silica in combination with silanised barium glass resulted in a material with the highest likelihood for dental applications in future. Keywords: copper; depth of cure; light transmission; linear shrinkage; mesoporous; polymerisation; polymerisation kinetics; polymerisation shrinkage stress.