Effects of immersion media and repolishing on color stability and superficial morphology of nanofilled composite resin

This study evaluated the influence of fluoride mouth rinses and repolishing on the superficial morphology and color stability of nanofilled resin. About 150 specimens were prepared and polished using aluminum oxide discs for 15 s with a pressure of 2 kg. The experimental groups were divided according to the immersion medium (artificial saliva, 0.5% sodium fluoride, Fluordent Reach, Oral B, Fluorgard) and repolishing procedure (without and with). The specimens were continuously immersed for 1 week. Thereafter, half of each sample was repolished. A color reading was performed after 24 h of immersion in the artificial saliva baseline, after continuous immersion, and after repolishing. The superficial morphology was examined using scanning electron microscopy (SEM) in a qualitative way. Color change (∆E) data were submitted to a mixed analysis of variance using a Shapiro-Wilk test (p>0.05 for the different immersion media) and Sidak's test (p<0.05 for the differences between groups). In the interaction between the repolishing and the immersion media, Fluorgard showed a statistical difference between the ∆E values with and without repolishing (p<0.0001). On the SEM observations, both Fluordent Reach and Fluorgard caused degradation of the superficial resinous matrix of the composite after continuous immersion. This matrix was removed after repolishing.

Metabolism of L929 cells after contact with acrylic resins. Part 1: Acrylic denture base resins

The purpose of this study was to evaluate the effectiveness of complementary heat treatment and water storage in reducing cytotoxicity of acrylic resins denture bases used in Brazil by the MTT assay. Material and Methods: First, nine specimens were fabricated from metal matrix in the form of discs with 14 mm in diameter and 1.2 mm of thick. Immediately after making, 24 or 48 hours after storage in distilled water, the samples of heat-polymerized resins were divided into 3 groups (n = 3) according to the type of thermal treatment: Group 1: samples were individually exposed to microwave energy (500 W for 3 minutes); Group 2: samples were immersed in water at 550 C for 60 minutes; Group 3: samples did not receive heat treatment. To prepare the extracts, 3 samples of each group were placed into vials containing 3 mL of culture medium and stored at 37°C for 24 hours. L929 cells were used and the MTT assay was performed to analyze the cellular metabolism. Two-factor analysis of variance was used to detect significant among groups at 5% significance. Results: After statistical analysis, the materials were classified according to the cytotoxic effect: non-cytotoxic, slightly cytotoxic; moderately cytotoxic; and strongly cytotoxic. The results showed that the resins ranged from moderately cytotoxic to non-cytotoxic, but no statistically significant difference among experimental groups. Furthermore, the water storage and thermal treatments reduced the cytotoxicity of the resins. Conclusions: It was concluded that the resins studied are potentially toxic and that treatments can decrease their cytotoxicity.

Colour stability of acrylic resin denture teeth after immersion in different beverages

The colour stability of acrylic resin denture teeth in beverages was investigated. A spectrophotometer measured the colour (CIE-L*a*b* system) of all specimens after storage in distilled water for 24 h at 37°C (T0). Specimens were then immersed in various beverages. After 15 days (T1) and 30 days (T2), for each material, the mean ∆E values were calculated and compared by two-way ANOVA and Tukey intervals (α=0.05). In the ∆T0T1 period, specimens stored in red wine were significantly discoloured, compared to distilled water (P=0.003). There was no difference between immersion solutions in ∆ET0T2 (P=0.772) and in ∆ET1T2 (P=0.058), and no difference between materials in all immersion periods.

Ação solvente do salicilato de metila sobre resilon e guta-percha

Objective: The aim of this study was to evaluate the action of methyl salicylate in dissolving Resilon and gutta-percha. Material and method: Ten discs of Resilon, Alpha gutta-percha and ProTaper gutta-percha were prepared (10 mm diameter × 1 mm thick) and kept at 37 °C for 48 hours. Each sample was weighed in a balance of accuracy determining the initial mass. The specimens were immersed in methyl salicylate or xylene (control) for 5  minutes, rinsed in water for 30 minutes, dried and subsequently weighed in 24 hours intervals until the stabilization of weight (final mass). The solvent capacity was expressed by the difference between the final and initial mass. The data were analyzed by using ANOVA and Tukey test with significance level of 5%. Result: The results showed that the methyl salicylate was more effective on Resilon than on gutta-percha (p < 0.05). Methyl salicylate and xylene had similar solvent action on Resilon (p > 0.05). The xylene showed better performance on gutta-percha than methyl salicylate (p < 0.05). Conclusion: It was concluded that methyl salicylate did not show solvent action on gutta-percha, however it showed effectiveness in dissolution of Resilon. Thus methyl salicylate can be a possible alternative to the use of xylene during endodontic retreatment of teeth obturated with Resilon.

Ph and antimicrobial activity of portland cement associated with different radiopacifying agents

The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers. Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the following strains: Micrococcus luteus, Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. After 24 hours of incubation at 37°C, inhibition of bacterial growth was observed and measured. For pH analysis, material samples (n=10) were placed in polyethylene tubes and immersed in 10 mL of distilled water. After 12, 24, 48, and 72 hours, the pH of the solutions was determined using a pH meter. Results. All microbial species were inhibited by the cements evaluated. All materials composed of PC with radiopacifying agents promoted pH increase similar to pure Portland cement. ZOE had the lowest pH values throughout all experimental periods. Conclusions. All Portland cement-based materials with the addition of different radiopacifiers (bismuth oxide, calcium tungstate, and zirconium oxide) presented antimicrobial activity and pH similar to pure Portland cement.

The effect of chlorhexidine on plaque index and mutans streptococci in orthodontic patients: A pilot study

Aim: The purpose of this study was to assess chlorhexidine effects on plaque index and salivary levels of mutans streptococci (MS) when used as the immersion solution for removable orthodontic appliances and added to their acrylic resin composition. Methods: Forty-five patients (6 to 12 years old) were randomly assigned into three groups with 15 patients each. Group I (control)—without orthodontic appliances disinfection; Group II—removable orthodontic appliances which had been immersed in 0.12% chlorhexidine digluconate overnight (8 hours), and Group III—orthodontic appliances in which 0.12% chlorhexidine digluconate solution had been incorporated into their resin composition. Saliva was collected for quantification of MS and evaluation of plaque index was performed before and after installation of orthodontic appliance at 0, 2, 4, 6, 8, and 10 weeks. Data were analyzed by using analysis of variance. Results: Number of MS colonies in saliva and plaque index showed no statistically differences among groups at the different periods (p > 0.05). Conclusions: It could be concluded that chlorhexidine incorporation into the acrylic resin of removable orthodontic appliances at 0.12% concentration and immersion of the appliance into 0.12% chlorhexidine solution were not effective in reducing plaque index and the number of MS in saliva.

Evaluation of the pH, calcium release and antibacterial activity of MTA Fillapex

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In vitro evaluation of Biosilicate® dissolution on dentin surface: a SEM analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In vitro study of color stability of polycrystalline and monocrystalline ceramic brackets

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo da aderência entre o concreto celular e as barras de aço

Pós-graduação em Engenharia Civil - FEIS

Corpo híbrido: corpo cotidiano e corpo artístico na prática da performance art

Pós-graduação em Artes - IA

Caracterização e aceitabilidade de tomate seco

In this work evaluated the content of vitamin C and total carotenoid in tomatoes fresh and dehydrated for conserve, with posterior immersion in sauce, verifying its sensorial acceptability. Dehydration was performed in dryer with airflow at 70 °C to obtain a product with final moisture of 45%. Determinations were carried out ascorbic acid, soluble solids, acidity, sugars and carotenoid before and after the dehydration process. The dehydrated tomatoes had been immersed in three types of sauces (pepper sauce, oregano with parrot leaves sauce and garlic sauce) per 25 days. After this period, the dry tomatoes in conserve had been submitted to the sensorial analysis in the pate form, applying themselves preference test. The results had been showed that retention of vitamin C and total carotenoid in the dehydrated product showed retention of 14.0% and 44.3%, respectively, in tomatoes after the dehydration process. Among the formulation of canned t

As tecnologias da informação no dispositivo pedagógico

Information technologies have enabled new forms of interactions among individuals, and can also be found in various educational institutions. However, despite appropriating new technological tools, educational practices continue to be based on a supposed pedagogical subject conceived as a transcendent way, ignoring his emergence and his origin in a particular historical period , and the control mechanisms by which is immersed. as well. This article aims to present results of an analysis on technology and education based on the thought of philosopher Michel Foucault. We analyzed proposals and discourses found in articles in a magazine entitled Patio - Revista Pedagógica.

Streptococcus mutans adhesion and releasing of metallic ions in dental alloys

AIM: To evaluate the adherence of Streptococcus mutans to the surface of the amalgam and copper/aluminum alloy samples and also evaluate the release of metallic ions. METHODS: The prepared medium was changed every 72 h and analyzed by atomic absorption spectrophotometer. Samples were removed from the prepared medium at 15, 30, 48 and 60 days. RESULTS: The result shows that ions released were statistically different among all groups, and so were both biofilm and pits formation and the corrosion induced by the S. mutans in both types of samples. SEM observation of the samples immersed in the prepared medium with S. mutans showed adherence of microorganisms on the whole surface, in all groups. CONCLUSIONS: The S. mutans adhere to both amalgam and copper/aluminum alloy causing corrosion of those restorations. S. mutans produced a greater ions release in Cu/Al alloy; in amalgam, the ions release was not influenced by exposure to S. mutans.

Unfaithful narratives: methodological and affective notes about experiences of masculinity in a dating website for married people

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)