Color change and force degradation of esthetic orthodontic elastic ligatures submitted to foods from the Amazonian diet/ Alteração de cor e degradação de forças de ligaduras elásticas ortodônticas estéticas submetidas a alimentos da dieta amazonense

The aim was to evaluate the color changes (?E*) and force degradation (FD) of esthetic elastic ligatures when submitted to foods from the Amazonian diet. 150 segments of elastics (n=10) (American Orthodontics - AO Orthoclassic - OC and Orthometric - OM) were divided to be submitted 2 times a day, for 1min each immersion, for 28 days, in one of the solutions: AI- açaí, CU- cupuaçu, TU- tucumã, RW- red wine and DW- distilled water (control). FD was evaluated using a universal testing machine and ?E* by spectrophotometer. Qualitative analyses were performed by scanning electron microscopy (SEM). The readings were taken at the following times: T0 - initial, T1 - 24 hours, T2 - 14 and T3 - 28 days. The FD and ?E* data were analyzed by non-parametric statistics (p<0.05). It was found that in the 3 brands, in all substances, there was a significant decrease in strength at T1 and at T2 there was an increase in strength. At T3, it is found that CU and DW promote significant differences from AI to OM and OC. For ?E* it was verified after 28 days in OM the ?E* was higher for the elastics submitted to TU and RW than in CU and DW. For OC, the variation was greater in DW than for TU and AI, whereas for AO there was no significant difference between the groups.  for all brands there is a higher FD in the first 24 hours, with elastic recovery after this period; all solutions promote FD in the evaluated elastics and, for all brands tested, the ?E* is clinically unacceptable after 28 days of immersion

Quantitative analysis of lead in polysulfide-based impression material

Permlastic® is a polysulfide-based impression material widely used by dentists in Brazil. It is composed of a base paste and a catalyzer containing lead dioxide. The high toxicity of lead to humans is ground for much concern, since it can attack various systems and organs. The present study involved a quantitative analysis of the concentration of lead in the material Permlastic®. The lead was determined by plasma-induced optical emission spectrometry (Varian model Vista). The percentages of lead found in the two analyzed lots were 38.1 and 40.8%. The lead concentrations in the material under study were high, but the product’s packaging contained no information about these concentrations

Color evaluation of a resin cement light polymerized by different light sources and submitted to potentially staining beverages

Abstract Introduction The color stability of resin cements, whether dual-pre-cured or photopolymerizable, as well as the color of the dental substrate, are fundamental for the aesthetic success of ceramic restorations, since the ceramic presents a high level of translucency due to its small thickness. Objective The aim of this in vitro study was to evaluate the color of a resin cement light polymerized by different light sources and immersed in potentially staining beverages. Material and method Were made 42 specimens of resin cement Variolink-Esthetic (2×6mm) (n=7), being half polymerized with LED light (F1) and half with Halogen light (F2). The specimens were stored in artificial saliva at 37 °C±1 °C. After 24 hours, they were polished with abrasive discs, and divided for the purpose of being submitted to the different solutions for 2 minutes per day, for 28 days, as follows: S1 – Coca-Cola; S2 – Red Wine; and S3 – Distilled Water (Control). Five color readouts were taken: T0 – initial; T1 – 7 days; T2 – 14 days; T3 – 21 days; and T4 – 28 days; with a spectrophotometer (Model SP62S). The color change data (ΔE*) were submitted to statistical analysis, ANOVA and Tukey (p≤0.05). Result Analyzing the factor solution, S2 (5.89 (±0.02)), produced a higher ΔE* value than S1 (3.79 (±0.02)) and (S1), a higher value than S3 (1.41 (±0.02)). Analyzing the factor light source, F2 (4.05 (±0.12)), produced a higher ΔE* value than F1 (3.33 (±0.12)). When analyzing the factor time, ΔE* values were found to increase gradually over the course of time: T1(2.36 (±0.08)); T2(3.27 (±0.08)); T3(4.06 (±0.08)); and T4(5.09 (±0.08)). Conclusion It was concluded that red wine produced a greater color change; Halogen light promoted highest degree of pigmentation; and the longer the time of immersion, the greater the color change of the material

Evaluación de la dureza superficial en amalgamas en función de tipos de aleaciones, momentos y tipos de pulimentos

<abstract language="eng">The aim of this study was to analyze in vitro surface hardness (micro-indentation tester Wolpert) of different types of amalgam alloys varying the technique and polishing time. Tested were the amalgam: Velvalloy, Permite e Dispersalloy. For each material, 2 polishing techniques were accomplished: T1 (bladed finishing burs + abrasive rubber points + pumice-water slurry in Robinson polishing brush) and; T2 (abrasive rubber points + pumice-water slurry in Robinson polishing brush), at 2 periods of time: P1 (immediately - 15 min after condensation) and P2 (after 24 h). For each experimental condition, 5 samples were prepared. For each sample, 2 indentations were taken and the average was determined. Were made analysis using ANOVA and Tukey test. Were concluded that: a) using the Permite alloy with polishing after 24 h the surface hardness of restoration will be higher; b) the technique T2 enhances the hardness of dental amalgams and c) alloy Permite with polished immediately were statisticaly equal than Velvalloy polished after 24 h

The influence of mouthrinses and simulated toothbrushing on the surface roughness of a nanofilled composite resin

The aim of this study was to determine the influence of mouthrinses on the surface roughness of a nanofilled composite resin after toothbrushing. One hundred nanofilled composite resin specimens were prepared and randomly distributed into two groups-brushed and non-brushed-and then assigned to five subgroups, according to the mouthrinse solutions (n = 10): Colgate Plax Fresh Mint, Oral B, Cepacol, Colgate Plax, and artificial saliva. Each sample was immersed in 20 mL of the mouthrinses for 1 minute, 5 days per week, twice a day, for a 3-week period. The control group used in the study was one in which the specimens were not subjected to brushing and remained only in artificial saliva. Toothbrushing was performed once a week for 1 minute, for 3 weeks. Surface roughness measurements (Ra) were performed after the immersion period and toothbrushing, by means of a profilometer. Data were analyzed by two-way ANOVA and Tukey's test. Analysis revealed that the association between toothbrushing and Colgate Plax Fresh Mint produced the lowest surface roughness (p < 0.05). All other groups tested (Oral B, Cepacol, Colgate Plax, artificial saliva) exhibited no statistically significant differences between surfaces, whether subjected to toothbrushing or not (p < 0.05). It was concluded that the surface roughness of the nanofilled composite resin tested can be influenced by the mouthrinse associated with toothbrushing