Systemic effects (risks) of water fluoridation

Since the 1950s, the benefits and risks of fluoridated water use have been debated worldwide. In the past, it was considered that the systemically ingested fluoride would exert its primary preventive effect after being incorporated into the enamel as fluorapatite, making the enamel more resistant to the caries process; however, it is now recognized that the main effect of water fluoridation is local and post eruptive. On the other hand, irrespective of the caries decline reported worldwide, the anticaries benefit of water fluoridation continues to be observed even in developed countries. Regarding the risks, water fluoridation is considered an acceptable community-based method for fluoride delivery, because the risk of developing dental fluorosis lesions due to the ingestion of fluoride during the enamel formation period has been deemed acceptable when contrasted to the anticaries benefits of fluoride. However, the use of fluoride in water to control caries has created a controversy due to data associating water fluoridation as the cause of some systemic diseases. Therefore, the aim of this descriptive review was to discuss the systemic effects (risks) of water fluoridation use305421428Based on the conference done by the 1st author at the 5th State Seminar Water and Health, CVS-SP/FSP-USP, São Paulo, Brazil, 12/10/201

Effect of sucrose on biofilm formed in situ on titanium material

Because sucrose may change the composition of biofilms formed on dental surfaces, the aim of this study was to evaluate in situ the effect of this dietary sugar on biofilm formation on titanium surface. In this blind, crossover, in situ study, 10 volunteers wore, in 3 phases of 7 days each, a palatal appliance containing titanium specimens. In each phase, the specimens were treated extraorally with 20% sucrose solution at a frequency of 4 or 8 times per day. As control, no treatment was rendered (0x). At the end of each phase, the biofilms were collected for biochemical analysis of biofilm wet weight (biomass), protein concentration, soluble (S-EPS), and insoluble (I-EPS) extracellular polysaccharides and intracellular polysaccharides (IPS), and for microbiologic analysis by checkerboard DNA-DNA hybridization (for levels and proportions of 40 bacterial species). Biochemical data were analyzed by linear regression and microbiological findings by Friedman and Dunn tests (alpha = .05). A positive significant linear relationship was found among sucrose exposure (0x, 4x, and 8x) and biomass, S-EPS, I-EPS and IPS (p < 0.05). The biofilms treated with sucrose (4x and/or 8x) presented higher mean total levels of the 40 bacterial species evaluated, higher proportions of red complex species and lower proportions of the host-compatible green complex species, in comparison with the control group (p < 0.05). The findings of the present study suggest that daily sucrose exposure has a harmful effect on the composition of biofilms formed on titanium surfaces902141148FAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo2015/23118-

Effect of chitosan dispersion and microparticles on older Streptococcus mutans biofilms

The effectiveness of chitosan to improve the action of antimicrobial compounds against planktonic bacteria and young biofilms has been widely investigated in Dentistry, where the biofilm lifecycle is a determining factor for the success of antibacterial treatment. In the present study, mature Streptococcus mutans biofilms were treated with chitosan dispersion (CD) or chitosan microparticles (CM). (2) Methods: CD at 0.25% and 1% were characterized by texture analysis, while CD at 2% was spray-dried to form CM, which were characterized with respect to particle size distribution, zeta potential, and morphology. After determining the minimum inhibitory and bactericidal concentrations, S. mutans biofilms were grown on glass slides exposed 8x/day to 10% sucrose and 2x/day to CD or CM at 0.25% and 1%. Biofilm viability and acidogenicity were determined, using appropriate control groups for each experiment. (3) Results: CD had high viscosity and CM were spherical, with narrow size distribution and positive zeta potential. CM affected bacterial viability and acidogenicity in mature S. mutans biofilms more strongly than CD, especially at 1%. (4) Conclusions: Both chitosan forms exerted antimicrobial effect against mature S. mutans biofilms. CM at 1% can reduce bacterial viability and acidogenicity more effectively than CD at 1%, and thereby be more effective to control the growth of mature biofilms in vitro249FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2015/04363-6; 2015/17712-

Visible-light-induced photocatalytic and antibacterial activity of TiO2 codoped with nitrogen and bismuth: new perspectives to control implant-biofilm-related diseases

Biofilm-associated diseases are one of the main causes of implant failure. Currently, the development of process and focuses on the creation of surfaces with implant surface treatment goes beyond the osseointegration antimicrobial action and with the possibility to be re-activated (i.e., light source activation). Titanium dioxide (TiO2), an excellent photocatalyst used for photocatalytic antibacterial applications, could be a great alternative, but its efficiency is limited to the ultraviolet (UV) range of the electromagnetic spectrum. Since UV radiation has carcinogenic potential, we created a functional TiO2 coating codoped with nitrogen and bismuth via the plasma electrolytic oxidation (PEO) of titanium to achieve an antibacterial effect under visible light with re-activation potential. A complex surface topography was demonstrated by scanning electron microscopy and three-dimensional confocal laser scanning microscopy. Additionally, PEO-treated surfaces showed greater hydrophilicity and albumin adsorption compared to control, untreated titanium. Bismuth incorporation shifted the band gap of TiO2 to the visible region and facilitated higher degradation of methyl orange (MO) in the dark, with a greater reduction in the concentration of MO after visible-light irradiation even after 72 h of aging. These results were consistent with the in vitro antibacterial effect, where samples with nitrogen and bismuth in their composition showed the greatest bacterial reduction after 24 h of dual-species biofilm formation (Streptococcus sanguinis and Actinomyces naeslundii) in darkness with a superior effect at 30 min of visible-light irradiation. In addition, such a coating presents reusable photocatalytic potential and good biocompatibility by presenting a noncytotoxicity effect on human gingival fibroblast cells. Therefore, nitrogen and bismuth incorporation into TiO2 via PEO can be considered a promising alternative for dental implant application with antibacterial properties in darkness, with a stronger effect after visible-light application11201818618202COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2017/00314-6; 2017/01320-0; 2016/11470-6This study was financed by the State of Sao Paulo Research Foundation (FAPESP) (grant numbers 2017/00314-6, 2017/01320-0 and 2016/11470-6) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001. We thank the Oral Biochemistry Lab at Piracicaba Dental School, University of Campinas, for providing their microbiology facility and the Brazilian Nanotechnology National Laboratory (LNNano) at the Brazilian Center of Research in Energy and Materials (CNPEM) for the CLSM, XPS, and XRD facilities. We also thank Professor Dr Ricardo Armini Caldas for his contribution to the elaboration of a table of contents graphic desig

The role of nicotine, cotinine and caffeine on the electrochemical behavior and bacterial colonization to cp-Ti

Although smoking promotes deleterious effect to bone healing, there is a lack of study investigating its role on the implant structure and biofilm growth. We hypothesized that nicotine, cotinine and caffeine would impair the corrosion resistance of commercially-pure titanium (cp-Ti) and would enhance Streptococcus sanguinis biofilm growth. Neither the smoking products nor the caffeine affected the corrosion tendency (P>.05) and the oxide layer resistance (P=.762) of cp-Ti. Lower capacitance values were noted in the presence of nicotine (P=.001) and cotinine (P=.0006). SEM showed no pitting corrosion, and the EDS spectra did not differ among groups. Nicotine (300μg/mL) induced higher surface roughness (P=.03) and greater surface change of cp-Ti. Nicotine at 3μg/mL, and cotinine at 0.3 and 3μg/mL increased the number of viable cells (P.05). These findings suggest a greater biofilm accumulation in smokers, a risk factor that may lead to peri-implantitis.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Three-species biofilm model onto plasma-treated titanium implant surface

In this study, titanium (Ti) was modified with biofunctional and novel surface by micro-arc oxidation (MAO) and glow discharge plasma (GDP) and we tested the development of a three-species periodontopatogenic biofilm onto the treated commercially-pure titanium (cpTi) surfaces. Machined and sandblasted surfaces were used as control group. Several techniques for surface characterizations and monoculture on bone tissue cells were performed. A multispecies biofilm composed of Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum was developed onto cpTi discs for 16.5 h (early biofilm) and 64.5 h (mature biofilm). The number of viable microorganisms and the composition of the extracellular matrix (proteins and carbohydrates) were determined. The biofilm organization was analyzed by scanning electron microscopy (SEM) and Confocal laser scanning microscopy (CLSM). In addition, MC3T3-E1 cells were cultured on the Ti surfaces and cell proliferation (MIT) and morphology (SEM) were assessed. MAO treatment produced oxide films rich in calcium and phosphorus with a volcano appearance while GDP treatment produced silicon-based smooth thin-film. Plasma treatments were able to increase the wettability of cpTi (p 0.05). Plasma treatment did not affect the viable microorganisms counts, but the counts of F. nucleaturn was lower for MAO treatment at early biofilm phase. Biofilm extracellular matrix was similar among the groups, excepted for GDP that presented the lowest protein content. Moreover, cell proliferation was not significantly affected by the experimental, except for MAO at 6 days that resulted in an increased cell proliferative. Together, these findings indicate that plasma treatments are a viable and promising technology to treat bone-integrated dental implants as the new surfaces displayed improved mechanical and biological properties with no increase in biofilm proliferation152354366CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP442786/2014-0; 304908/2015-02013/26145-5; 2013/08451-