Aim To determine the prevalence of dental development anomalies and type of influence on the smile of adolescent students. Method This was a cross-sectional and analytical study carried out in two public (A1) and two private (A2) schools chosen by lot in the city of Parnaíba-Piauí. The sample calculation was based on the target population: number of people enrolled in public and private schools between 15 and 19 years, in the city of Parnaíba-PI, which totaled 6209 students in 2020, according to a survey carried out by the Brazilian Institute of Geography and Statistics – IBGE. A questionnaire on epidemiological data and aesthetic self-perception of the smile was applied to 160 adolescents between 15 and 19 years old, from August 2020 to July 2021. The clinical examination was carried out under natural light, to check for the presence of anomaly(s) in the dental development. Students who presented only one pathology would be called group 1 (G1), those who presented two would be called group 2 (G2) and those who presented 3 or more would be called group 3 (G3). On the other hand, adolescents in whom no anomaly was evidenced would participate in the control group (CG), both in A1 and A2. Results It was observed that 37.5% of the sample had only a type of dental anomaly, corresponding to 60 individuals. The most prevalent were enamel hypoplasia, fusion, transposition, agenesis, ectopic eruption, microdent and dens-in-dent. It was possible to verify a higher prevalence in the maxilla, private schools (76.6%) and females (86.6%). In 45% of adolescents with dental anomalies, embarrassment was observed when smiling. Conclusion The prevalence was relatively high, highlighting the enamel hypoplasia, influencing the smile esthetics of a reasonable number of adolescents, whether for acquaintances, strangers or even for photographs.

Aim To evaluate the prevalence and factors associated with gummy smiles in adolescents aged between 15 and 18 years attending high school. Methods The cross-sectional and quantitative study was carried out during the Covid-19 pandemic, with 160 adolescents, from two public (A1) and two private (A2) schools chosen by lottery, divided into two groups: G1 (with gummy smile) and G2 (no gummy smile). A clinical examination was carried out on the adolescents, investigating the presence or absence of a gummy smile (GS), by analyzing the variables (interlabial distance at rest, upper incisor exposure at rest, smile arc, measurement from the subnasal to the upper lip philtrum, upper lip length, upper lip thickness, hypermobility and lower/middle third ratio). Means and dispersion were obtained, and the Chi-square association test was applied, to compare the results between A1 and A2 and between G1 and G2. Results The prevalence of GS was 33.8% (=54). It was found that no statistically significant associations were found (p > 0.05), regarding the type of school and gender with the presence of GS in adolescents. There was no statistically significant difference (χ2 = 1.82; p = 0.07) between the groups and the age of adolescents. There was a significant association between the studied variables and GS (p < 0.05). Conclusion The prevalence was high with a predominance of females. There were no statistically significant associations regarding the type of school and gender, but there was a significant association between gummy smile and lip dimensions.

The main challenge for the development of a high efficiency supercapacitor is the electrode material. Developing electrode materials with high specific electrical capacitance and low electrical resistance enables an increase in the energy accumulated in the device. In addition, it is expected that the electrode material presents a simple procedure for preparation having low production cost and being environmentally friendly. This work is based on the deposition of silver nanoparticles on activated carbon felt (Ag@ACF) as a supercapacitor electrode. The samples were characterized by field emission gun scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and textural analysis. Supercapacitor behavior was evaluated by galvanostatic charge-discharge curves, cyclic voltammetry and electrochemical impedance spectroscopy using a symmetrical two-electrode Swagelok type cell, and three different aqueous solution electrolytes: 2 M H2SO4, 6 M KOH and 1 M Na2SO4. Ag@ACF presented a high specific capacitance in KOH, about 170 F g-1, which makes it an interesting material for supercapacitor electrodes and it showed good specific electrical capacitance, low resistance and high cyclability.

Several coatings have been proposed as an alternative to replacement processes based on hexavalent chromium. Among them stand out the hybrid films. Some hybrids films, with modified composition by the addition of photoinitiators, can be cured by ultraviolet system (UV). The UV cure is the instantaneous conversion of a reactive liquid in a solid induced by radiation, starting from the polymerization and cross-linking reactions of the chemical species. In order that reaction takes place through the action of UV radiation, it is necessary to add, in the composition of the hybrid film, a substance sensitive to this radiation called photoinitiator. The aim of this work is the preparation and characterization of hybrid films, cured by UV, from TEOS and TMSPMA alkoxide precursors, with addition of photoinitiators with different concentrations (1 and 2%) and without photoinitiator on galvanized steel. The films were characterized concerning the morphology, physicochemical properties and electrochemical behavior. The presence and the increase of photoinitiator concentration on hybrid films improved corrosion resistance of the system.

Galvanized steel was coated with a hybrid film obtained from a solution formed by silane precursor 3-(trimethoxysilyl) methacrylate (TMSPMA) and tetraethoxysilane (TEOS) with addition of cerium. The use of hybrid organic-inorganic layers represents an environmentally friendly alternative to improve resistance against corrosion of a series of metallic materials. Three immersion times (2, 10 and 15 minutes) were used and the films were characterized by scanning electron microscope evaluating film wetability was at the same time. The electrochemical behavior of the coatings obtained was evaluated by open circuit potential, potentiodynamic polarization and electrochemical impedance. The results showed the effect of immersion time in the solution on the film uniformity and consequently on the corrosion resistance of these films.

Acero galvanizado fue revestido con una película híbrida a partir de una solución formada por los precursores silanos 3-(trimetoxisililpropil) metacrilato (TMSPMA) y tetraetoxisilano (TEOS) con adición de cerio. El uso de capas hibridas orgánico-inorgánico representa una alternativa ambientalmente aceptable para mejorar la resistencia de una serie de materiales metálicos frente a los procesos corrosivos. Se emplearon tres tiempos de inmersión (2, 10 y 15 minutos) y se caracterizaron las películas mediante microscopia electrónica de barrido, evaluando también el carácter hidrofóbico de las películas. El comportamiento electroquímico de los revestimientos obtenidos fue determinado por el monitoreo del potencial de circuito abierto, polarización potenciodinámica e impedancia electroquímica. Los resultados que se obtuvo evidenciaron el efecto del tiempo de permanencia dentro de la solución en la uniformidad de la película y consecuentemente sobre la resistencia a la corrosión del mismo.