Aspectos relacionados a procedimentos restauradores em odontopediatria

O objetivo deste texto foi realizar uma revisão crítica de trabalhos realizados após o doutoramento do autor, de parte de uma linha de pesquisa focalizada na dentística em odontopediatria. Desta forma, foram revisados artigos referentes a alguns procedimentos realizados na prática da odontologia restauradora, envolvendo estudos de microinfiltração, onde foi avaliada a influência de técnicas e materiais restauradores sobre este fenômeno. Outros trabalhos revisados relacionaram-se ao uso do microscópio eletrônico de varredura. Neste caso, foram descritos estudos que avaliaram aspectos micromorfológicos das estruturas dentárias (esmalte e dentina) de dentes permanentes, mas principalmente decíduos. Foram observados os efeitos de diferentes tratamentos realizados sobre as estruturas dentárias, como a ação de agentes condicionadores e métodos de desgaste das estruturas dentárias (laser, abrasão a ar, instrumentos cortantes rotatórios e ponta CVD). Também foram apresentados os trabalhos que avaliaram a interface adesiva, após diferentes tratamentos da dentina. Finalmente foram realizados comentários sobre os trabalhos revisados e apresentadas as tendências futuras desta linha de pesquisa.

Estrutura do esmalte humano e sua interface com sistemas adesivos

Esta tese sistematiza uma série de estudos dedicados à compreensão da interface do esmalte e sistemas adesivos. Para tanto, a estrutura da camada aprismática do esmalte em alta resolução pela microscopia eletrônica de varredura foi avaliada quanto a sua continuidade, espessura, distribuição nas faces coronárias e em fossas e fissuras, predominantemente em dentes decíduos não erupcionados. Foi também analisado pela microscopia eletrônica de varredura os efeitos do condicionamento de diferentes tipos de ácido e, em especial, do ácido fosfórico em diferentes concentrações, metodologias e tempos de aplicação. Estes trabalhos permitiram visualizar as principais ações ácidas desmineralizantes e os tipos de retenções no centro ou periferias dos prismas ou em ambas as regiões, bem como a profundidade e forma dos “tags” resinosos com carga e sem carga na intimidade do esmalte. No caso particular da aplicação dos selantes em fossas e fissuras foi também avaliada comparativamente a eficácia das técnicas invasivas ou não invasivas. Os últimos experimentos foram dedicados ao estudo da microinfiltração de diferentes sistemas adesivos e da resistência destes sistemas adesivos na estrutura do esmalte. Novos estudos merecem dar continuidade à linha de pesquisa de sempre priorizando o propósito de vincular os procedimentos aplicados com uma consistente e indispensável fundamentação de pesquisa básica no interesse da clínica odontopediátrica.

Mechanisms of action of fluoridated acidic liquid dentifrices against dental caries

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

Effect of delayed start of light-curing on microtensile bond strengths of two adhesives bonded to dentin

The aim of the present study was to evaluate the microtensile bond strength to dentin (ATBS) of two total-etching adhesives applied with delays of 1-30 s for curing. Fifty extracted molar teeth were used. Occlusal enamel was sectioned to expose flat dentin surface, which was further polished with 600-grit paper for smear layer standardization. The specimens were divided into two groups, G1: Single Bond total-etching adhesive (SB), and G2: Prime & Bond NT total-etching adhesive (PB). Each group was further divided into 5 subgroups according to the delayed light-cure initiation after the adhesive systems application (n=5): Subgroup 1s - 1 s; Subgroup 5s -5 s; Subgroup 10s - 10 s; Subgroup 20s - 20 s; Subgroup 30s - 30 s. Composite resin cones 5 mm height and 10 mm in diameter were fabricated. Specimens were stored in distilled water at 37 degrees C for 24 h and sectioned to obtain 1 x 1 mm(2) transversal specimens. Specimens were thermocycled and mu TBS was measured. Data were submitted to two-way ANOVA (AdhesiveXDelay time) and Tukey's test. The level of significance was set at 5%. The results in mean MPa(+/- SD) for interaction between adhesive and delay time were: PB/1s - 23.82 +/- 2.54a; SB/5s - 19.52 +/- 2.67b; PB/5s - 18.56 +/- 3.06bc; SB/1s - 15.49 +/- 2.69cd; SB/20s - 16.33 +/- 2.55d; SB/10s - 13.88 +/- 1.67d; PB/10s - 11.04 +/- 1.28e; PB/30s - 10.89 +/- 1.31e; PB/20s - 10.24 +/- 2.33e; SB/30s - 9.19 +/- 1.91e. It was concluded that light-cure initiation timing of total-etching adhesives interferes negatively with mu TBS to dentin. (C) 2014 Elsevier Ltd. All rights reserved.

Effect of grinding with diamond-disc and -bur on the mechanical behavior of a Y-TZP ceramic

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Impact of bariatric surgery on oral health conditions: 6-months cohort study

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

Beneficial Effects of Adiponectin on Periodontal Ligament Cells under Normal and Regenerative Conditions

Type 2 diabetes and obesity are increasing worldwide and linked to periodontitis, a chronic disease which is characterized by the irreversible destruction of the tooth-supporting tissues, that is, periodontium. The mechanisms underlying the association of diabetes mellitus and obesity with periodontal destruction and compromised periodontal healing are not well understood, but decreased plasma levels of adiponectin, as found in diabetic and obese individuals, might be a critical mechanistic link. The aim of this in vitro study was to examine the effects of adiponectin on periodontal ligament (PDL) cells under normal and regenerative conditions, and to study the regulation of adiponectin and its receptors in these cells. Adiponectin stimulated significantly the expression of growth factors and extracellular matrix, proliferation, and in vitro wound healing, reduced significantly the constitutive tumor necrosis factor-alpha expression, and caused a significant upregulation of its own expression. The beneficial actions of enamel matrix derivative on a number of PDL cell functions critical for periodontal regeneration were partially enhanced by adiponectin. The periodontopathogen Porphyromonas gingivalis inhibited the adiponectin expression and stimulated the expression of its receptors. In conclusion, reduced levels of adiponectin, as found in type 2 diabetes and obesity, may compromise periodontal health and healing.

Proteins, Pathogens, and Failure at the Composite-Tooth Interface

In the United States, composites accounted for nearly 70% of the 173.2 million composite and amalgam restorations placed in 2006 (Kingman et al., 2012), and it is likely that the use of composite will continue to increase as dentists phase out dental amalgam. This trend is not, however, without consequences. The failure rate of composite restorations is double that of amalgam (Ferracane, 2013). Composite restorations accumulate more biofilm, experience more secondary decay, and require more frequent replacement. In vivo biodegradation of the adhesive bond at the composite-tooth interface is a major contributor to the cascade of events leading to restoration failure. Binding by proteins, particularly gp340, from the salivary pellicle leads to biofilm attachment, which accelerates degradation of the interfacial bond and demineralization of the tooth by recruiting the pioneer bacterium Streptococcus mutans to the surface. Bacterial production of lactic acid lowers the pH of the oral microenvironment, erodes hydroxyapatite in enamel and dentin, and promotes hydrolysis of the adhesive. Secreted esterases further hydrolyze the adhesive polymer, exposing the soft underlying collagenous dentinal matrix and allowing further infiltration by the pathogenic biofilm. Manifold approaches are being pursued to increase the longevity of composite dental restorations based on the major contributing factors responsible for degradation. The key material and biological components and the interactions involved in the destructive processes, including recent advances in understanding the structural and molecular basis of biofilm recruitment, are described in this review. Innovative strategies to mitigate these pathogenic effects and slow deterioration are discussed.

Cimetidine Reduces Alveolar Bone Loss in Induced Periodontitis in Rat Molars

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

Estudo in vitro da anatomia das projeções de esmalte cervical em dentes molares

The cervical enamel projection (CEP) is an anatomic variation that can be found in the cement enamel junction, it´s recognition and early diagnosis improves outcome the tooth involved, allowing greater efficiency in treatment. The knowledge of the location, grade and incidence of CEP is decisive on prevention and treatment of periodontal disease. It were studied 1200 molars (600 mandibular molars and 600 maxillary molars) separated from the collection of teeth on the Discipline of Anatomy in FOSJCampos - UNESP. Each group of 600 teeth was separated from the second side (300 teeth) and the second type (first, second or third molar). Each tooth had thoroughly inspected the cervical region, in all their faces, in order to verify the incidence and the grade of CEP in each surface. It was found that the CEP covered in 278 (23,17%) teeth was 146 (52,52%) mandibular molars and 132 (47,48%) maxillary molars. The CEPs were concentrated on a tooth surface in 222 (79,86%) teeth, in two surfaces 53 (19,06%) teeth, and in three surfaces in three (1,08%) teeth. From the total of 4.800 surfaces examined the CEPs were found in 337 surfaces, and 228 (67,66%) surfaces of the grade I, 60 (17,8%) grade II and 49 (14,54%) grade III. The buccal surface presented 207 (61,42%) CEP, the lingual surface in 57 (16,91%), the mesial surface in 35 (10,39%) and the distal surface in 38 (11,28%) CEP. The results of this study demonstrated that the CEPs have focused more on the mandibular teeth on only one surface of the tooth, the grade I was the most found and the buccal surface the most involved

Efeito da ativação física e química do gel clareador na velocidade de penetração do peróxido de hidrogênio: estudo in vitro

This study evaluated the effect of physical and chemical activation on the speed of penetration of hydrogen peroxide bleaching agents present in different concentrations through the enamel and dentin. One hundred and twenty bovine incisors were used, which were obtained enamel/dentin discs of the buccal surface, with 6 mm in diameter. The samples were divided into six groups: G1 - Hydrogen Peroxide Gel 20%, G2 - Hydrogen Peroxide Gel 20% with light activation, G3 - Hydrogen Peroxide Gel 20% with Manganese Gluconate; G4 - Hydrogen Peroxide Gel 35%; G5 - Hydrogen Peroxide Gel 35% with the light activation and G6 - Hydrogen Peroxide Gel 35% with Manganese Gluconate. The specimens were placed in a transparent support on which there was a substance sensitive to hydrogen peroxide immediately below and in contact with the specimen. After the procedures for applying the gel for each group, one video camera was positioned and operated to monitor the time of penetration of peroxide in each specimen. The recording ended after changing the color of the fluid revealed in all specimens and times were noted for comparison. ANOVA analysis showed that concentration and type of activation of bleaching gel significantly influenced the diffusion time of hydrogen peroxide (P 0.05). 35% hydrogen peroxide showed the lowest diffusion times compared to the groups with 20% hydrogen peroxide gel. The light activation of hydrogen peroxide decrease significantly the diffusion time compared to chemical activation. The highest diffusion time was obtained with 20% hydrogen peroxide chemically activated. The diffusion time of hydrogen peroxide was dependent on activation and concentration of hydrogen peroxide. The higher concentration of hydrogen peroxide diffused through dental tissues more quickly

Utilização de técnicas de planejamento de experimentos na análise de viabilidade de alterações no processo de pintura de grades Antracite em uma indústria automotiva

The search for better performance and competitive advantage in the current market scenario has made organizations keep their focus on quality planning and the use of effective techniques aimed at continuous improvement and optimization of processes and resources. The situation is not different for the painting process in the automotive industry, which has a significant amount of variables and influential external factors. This work, developed at General Motors in São José dos Campos, aims to analyze the feasibility of changing the painting process of the pickup S10 railings in the Antracite color located in the main line to the another line located in a Painting Repair Booth at the plant and, therefore, to study the possibility about reducing the window of cure for Antracite’s enamel by using Design of Experiments’ techniques. Applying this method is possible to find the best arrangement among studied factors of Painting Repair Booth that are, in this case, the Temperature, in Celsius degrees, and Skid’s Steps, in seconds, and it’s also possible to get their behavior according to quality requirements specified by GM rules for the Brightness and Paint Adhesion on the part. As a result, it can conclude that is possible to paint the S10 Antracite railings in the painting process’ line of Painting Repair Booth, and with the new configuration obtained by the Design of Experiments for the process variables, there are significant gains related to the parts’ quality, costs reduction and the optimization of production capacity, much in the main line as in the line of the Painting Repair Booth

Micromorfologia e anatomia floral das seções neotropicais de Bulbophyllum Thouars (Orchidaceae, Asparagales): considerações taxonômicas e evolutivas

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

Efeito de dentifrícios fluoretados e suplementados com nanopartículas de trimetafosfato de sódio sobre a desmineralização, remineralização e erosão dentária

Pós-graduação em Ciência Odontólogica - FOA

Efeito de vernizes fluoretados suplementados com trimetafosfato de sódio na desmineralização e remineralização do esmalte bovino: estudos in vitro e in situ

Pós-graduação em Ciência Odontólogica - FOA