Collapse and Color Changes in Grapefruit Juice Powder as Affected by Water Activity, Glass Transition, and Addition of Carbohydrate Polymers

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of Hydrogen Peroxide Bleaching Gels on Color, Opacity, and Fluorescence of Composite Resins

The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (p<0.05). Color changes were significant for different tested bleaching therapies (p<0.0001), with the greatest color change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (p<0.0001) and bleaching therapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.

Application of compression test in analysis of mechanical and color changes in grapefruit juice powder as related to glass transition and water activity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

An evaluation of ocean color model estimates of marine primary productivity in coastal and pelagic regions across the globe

Nearly half of the earth's photosynthetically fixed carbon derives from the oceans. To determine global and region specific rates, we rely on models that estimate marine net primary productivity (NPP) thus it is essential that these models are evaluated to determine their accuracy. Here we assessed the skill of 21 ocean color models by comparing their estimates of depth-integrated NPP to 1156 in situ C-14 measurements encompassing ten marine regions including the Sargasso Sea, pelagic North Atlantic, coastal Northeast Atlantic, Black Sea, Mediterranean Sea, Arabian Sea, subtropical North Pacific, Ross Sea, West Antarctic Peninsula, and the Antarctic Polar Frontal Zone. Average model skill, as determined by root-mean square difference calculations, was lowest in the Black and Mediterranean Seas, highest in the pelagic North Atlantic and the Antarctic Polar Frontal Zone, and intermediate in the other six regions. The maximum fraction of model skill that may be attributable to uncertainties in both the input variables and in situ NPP measurements was nearly 72%. on average, the simplest depth/wavelength integrated models performed no worse than the more complex depth/wavelength resolved models. Ocean color models were not highly challenged in extreme conditions of surface chlorophyll-a and sea surface temperature, nor in high-nitrate low-chlorophyll waters. Water column depth was the primary influence on ocean color model performance such that average skill was significantly higher at depths greater than 250 m, suggesting that ocean color models are more challenged in Case-2 waters (coastal) than in Case-1 (pelagic) waters. Given that in situ chlorophyll-a data was used as input data, algorithm improvement is required to eliminate the poor performance of ocean color NPP models in Case-2 waters that are close to coastlines. Finally, ocean color chlorophyll-a algorithms are challenged by optically complex Case-2 waters, thus using satellite-derived chlorophyll-a to estimate NPP in coastal areas would likely further reduce the skill of ocean color models.

Differentiation of floral color and odor in two fly pollinated species of Metrodorea (Rutaceae) from Brazil

We investigated if differences in morphological characters in two species of Metrodorea (Rutaceae) from Brazilian semideciduous forests correspond to some pollination divergence. M. nigra and M. stipularis are sympatric species, display a similar floral morphology, are protandrous, self-incompatible, their flower periods overlap, and both are pollinated by flies. M. nigra main pollinators are Pseudoptiloleps nigripoda (Muscidae) and Fannia sp. (Fanniidae); M. stipularis major pollinators are Phaenicia eximia (Calliphoridae), Palpada sp. and Ornidia obesa (Syrphidae). The distinct floral odor (disagreeable in M. nigra and sweet in M. stipularis) and color (brownish violet vs. pale yellow) determine the differences on type and number of floral visitors observed. Several species from semideciduous forests initially considered to be pollinated by diverse insects, present flies as main pollinators, stressing the importance of fly pollination in such habitats.

Odontomas in pediatric dentistry: Report of two cases

Odontomas are developmental disturbances which manifest in the form of denticles or amorphous informes masses comprising all dental tissues, especially enamel and dentin, with variable amounts of pulp and cement. We describe here two clinical cases of odontomas in children, focusing on diagnostic means and the importance of early treatment of these lesions. The standard treatment for the two present cases was surgical removal.

Dentistry and HIV: University professors' role in establishing a basis for judgment

The aim of this study was to determine whether there are differences in the attitudes of Dentistry School Professors from two universities, one private and one public concerning HIV-positive patients or HIV-positive health care professionals. A questionnaire Was handled to all profession at the Araçatuba Dental School of São Paulo State University - FOA-UNESP (public) and Lins Dental School of the Piracicaba Methodist University - FOL-UNIMEP (private). When asked if they would be willing to be treated by an HIV-infected health care professional, 38.9% of the 77 professors at FOA-UNESP replied that they would accept only non-invasive treatments and 13% would not accept any kind of treatment; the same applied to 42.4% and 15.2% of the 33 FOL-UNIMEP professors. Among the 54 professors at FOA-UNESP and 27 at FOL-UNIMEP providing clinical service, only 31.5% and 18.5% stated that they treat HIV-infected persons like any other patient. The results were very similar in both schools. Although they reported that they taught their students not to act in a discriminatory manner towards HIV-positive patient the professors themselves showed prejudice towards infected patients and professionals. Consequently, this topic trust be further debated in the academic milieu.

Ozone therapy in medicine and dentistry

Aim: The purpose of this review is to present the potential for the incorporation of ozone therapy into the practice of dentistry. Background: Ozone gas has a high oxidation potential and is 1.5 times greater than chloride when used as an antimicrobial agent against bacteria, viruses, fungi, and protozoa. It also has the capacity to stimulate blood circulation and the immune response. Such features justify the current interest in its application in medicine and dentistry and have been indicated for the treatment of 260 different pathologies. It can be used for the treatment of alveolitis as a replacement for antibiotic therapy, as a mouthwash for reducing the oral microflora, as well as the adherence of microorganisms to tooth surfaces. Ozone has been shown to stimulate remineralization of recent caries-affected teeth after a period of about six to eight weeks. Conclusion: The future of ozone therapy must focus on the establishment of safe and well-defined parameters in accordance with randomized, controlled trials to determine the precise indications and guidelines in order to treat various medical and dental pathologies. Scientific support, as suggested by demonstrated studies, for ozone therapy presents a potential for an atraumatic, biologically-based treatment for conditions encountered in dental practice.

Visual evaluation of color stability after accelerated aging of pigmented and nonpigmented silicones to be used in facial prostheses

Objectives: The objective of this study was to evaluate by a visual method of comparison the color stability of nonpigmented and pigmented facial silicones after accelerated aging. Materials and Methods: Two kinds of silicones were used in this study; one specifically formulated for facial prostheses and the other an acetic silicone for industrial use. Twenty-four trial bodies were made for each silicone. These were divided into colorless and intrinsically pigmented groups: ceramic, make-up, and iron oxide. The groups were submitted to accelerated aging for nonmetallic materials. An initial reading and subsequent readings were made at 163, 351, 692, and 1000 hours using a visual method of comparison. The values were annotated in a spreadsheet by two observers, according to scores elaborated for this study. Results: All groups presented color stability in the visual method. According to the results obtained and analyzed in this study, we can conclude that both silicones, Silastic 732 RTV and Silastic MDX 4-4210, behaved similarly, they can therefore be indicated for use in maxillofacial prosthesis. The time factor of aging influenced negatively, independently of the pigmentation, or lack of it, and of silicones and no group had visually noticeable alterations in any of the accelerated aging time, independently of the addition or not of pigments.

Evaluation of hardness and color stability in the soft lining materials after thermocycling and chemical polishing.

The aim of this study was to evaluate the Shore A hardness and color stability of two soft lining materials after thermocycling and when chemical polishing was used or omitted. Two acrylic-based soft lining materials were tested: Coe-Soft and Soft Confort, 14 specimens were made for each material. They were distributed in four groups according to the treatment performed. The specimens were thermocycled (1000 cycles) and half of the group submitted to chemical polishing (methyl methacrylate). Shore A hardness was determined and color stability was calculated by means of Commission International de l'Eclairage Lab uniform color scale using a spectrophotometer, the measurements were made immediately after deflasked, chemical polishing and thermocycling. Analysis of variance (ANOVA) and Tukey's tests were performed at p < 0.01. Color changes (deltaE) were observed after thermocycling in both soft lining materials: Soft Confort (10.60) showed significantly higher values than Coe-Soft (4.57). Coe-Soft (26.42) showed higher Shore A hardness values than Soft Confort (19.42). Chemical polishing did not influence in the color stability of both materials; however, influenced in the hardness values of Coe-Soft.

Color alteration of the paint used for iris painting in ocular prostheses

The purpose of this study was to assess color alteration of the paints used for iris painting in artificial eyes. Five disks of heat cured acrylic resin were confectioned by microwave energy for each paint analyzed, in a total of 40 specimens. Each specimen consisted of a colorless acrylic resin disk and another of equal size, of scleral white colored acrylic resin, with the painting interposed between the two disks. The specimens were submitted to an accelerated aging process in a chamber under ultraviolet radiation for 1,008 hours. To assess color variation, a reflective spectrophotometer was used. The results were statistically analyzed by ANOVA and the Tukey test (p < 0.05). All the paints underwent chromatic alteration. The oil paint presented the highest resistance to accelerated aging.

Color stability after accelerated aging of two silicones, pigmented or not, for use in facial prostheses

One of the greatest challenges faced by buccomaxillofacial prosthetists is to reproduce the patient's exact skin color and provide adequate esthetics. To reach this objective, professionals must use materials with easy characterization and that maintain color over long periods of time. The objective of this study was, thus, to evaluate the color stability of two types of silicones, Silastic 732 and Silastic MDX4-4210. Twenty-four test specimens were made from each type of silicone and were divided into a colorless group and groups intrinsically pigmented with ceramics, cosmetics or iron oxide. The specimens were submitted to an accelerated system of aging for non-metallic materials. Readings were carried out initially and after periods corresponding to 163, 351, 692 and 1,000 hours of aging, using a reflection spectrophotometer analysis, and color alterations were calculated by the CIE L*a*b* system. The data were submitted to variance analysis and Tukey's test at a 5% level of probability. The results demonstrated that, irrespective of the period of time analyzed, all the materials underwent some type of chromatic alteration (ΔE > 0). The test specimens made with Silastic 732 and MDX4-4210, without pigmentation, presented the lowest color alteration values after 1,000 hours of aging. Of the pigments, ceramic presented the lowest color alteration values and cosmetic powder presented the highest values. Thus, it may be concluded that the materials without the incorporation of pigments presented similar color alteration values, and did not differ statistically. The cosmetic powder used in this study was the pigment that most altered the color of the test specimens. © 2009 Sociedade Brasileira de Pesquisa Odontológica.

Verruciform xanthoma located in anterior gingival

Verruciform xanthoma (VX) is a relatively rare benign lesion and oral predominantly, which occasionally affects skin and genital mucosa. It appears as a papule or single plaque showing a verrucous or papillomatous aspect, with variable color from reddish pink to gray. In majority of oral cases, it affects gingiva and alveolar mucosa such a solitary lesion. Histopathological findings are foamy histiocytes within elongated dermal papillae. Treatment consists of conservative excision surgery and recurrence is rare. A clinical case is reported, located in anterior gingiva, showing good prognosis, without recurrence. There was no concomitant oral lesion associated. Local trauma was the only possibility suggested to be related to etiology. No relevant alterations in laboratory exams (hemogram, total cholesterol, HDL, LDL, VLDL, glycose and glycolized hemoglobin) were found. The origin of the lesion remains unclear and investigation for possible associations with other lesions that could present greater risk of carcinogenesis is required. © Medicina Oral S.L.