Influence of resin-composite formulation on the intra-oral degradation : in vitro study

Orientadores: Luiz Andre Freire Pimenta, Lourenço Correr SobrinhoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Dentes naturais, bem como restaurações estão sujeitos à degradação inta-oral. Nas resinas compostas, além das interferências químicas, térmicas e mecânicas, a composição e a estrutura pós-cura são mecanismos considerados responsáveis pela durabilidade do procedimento restaurador. Neste estudo, avaliou-se o efeito da formulação do material, métodos de fotoativação (MF) e condições de armazenamento (CA) na resistência à degradação química e/ou mecânica de resinas-compostas. Os objetivos, métodos e resultados deste trabalho, composto por dois artigos científicos foram: CAPÍTULO 1: avaliar como o MF e a CA afetam a degradação química (DQ) de duas resinas-compostas de nanopartículas, um ormocer de 1a e um de 2a geração. Discos de 4 mm de diâmetro e 2 mm de altura foram confeccionados e fotoativados com os métodos convencional (C) ou soft-start (S). Testaram-se quatro CA (n=5): grupo 1: imediato; grupo 2: seco e escuro; grupo 3: etanol e grupo 4: água destilada. A dureza Knoop (KHN) foi mensurada imediatamente após a cura e 24 horas após armazenagem. Aplicaram-se os testes estatísticos two-way ANOVA e Tukey (p=0.05) comparando os valores de KHN entre as CA e entre os MF. O MF não interferiu na DQ de nenhum material testado. Entretanto, diferenças foram observadas entre as CA, e independente do material, o etanol produziu a maior DQ. O ormocer de 2a geração foi o único material que não degradou após imersão em água. Concluiu-se que: o MF não influenciou na resistência à DQ; o etanol causou maior DQ e o ormocer de 2a geração foi o material mais estável em água após 24 h de armazenamento. CAPÍTULO 2: investigar o efeito do tamanho de partículas de carga na rugosidade superficial (RS), retenção de brilho (RB) e estabilidade de cor (C) antes e após abrasão utilizando a escovação mecânica (EM). Avaliaram-se quatro resinas-compostas experimentais e uma comercial com partículas variando de 100 a 1000 nm. Para cada material, seis discos medindo 10 mm de diâmetro e 2 mm de altura foram confeccionados. Após acabamento e polimento, as amostras foram submetidas a 20.000 ciclos de EM. Os parâmetros RS, RB e C foram mensurados antes e após escovação. Aplicaram-se os testes estatísticos de ANOVA e Bonferroni (p=0.05) e o teste de correlação de Pearson para determinar a relação entre tamanho das partículas e os parâmetros avaliados; e a relação entre RS e RB. A EM resultou em superfícies mais rugosas e menos brilhantes para todos materiais testados. Após a EM houve correlação significativa entre o tamanho das partículas e os parâmetros de rugosidade Ra (r = 0.95/ p = 0.013) e Rt (r = 0.93 / p = 0.022). Não houve correlação significativa entre o tamanho das partículas e ?E*. Houve correlação negativa significante entre brilho e rugosidade (r = - 0.97 / p = 0.001). Concluiu-se que a abrasão causou modificações na rugosidade, relacionadas ao tamanho das partículas, e no brilho dos materiais testados. A C não foi alterada pelo tamanho das partículas de carga e nem por modificações na textura superficialAbstract: Natural teeth, as well as restorations, are composed of materials that are subject to deterioration. Besides chemical, mechanical and thermo degradation, the formulation and post-cure composite¿s network are dominant mechanism to determine the restoration¿s longevity. The purpose of this study was to investigate the effect of material¿s formulation, light-activation mode (LM) and storage condition (SC) on resin-composite¿s resistance to chemical and/or mechanical degradation. The aims, methods and results of this study, composed of two chapters were: CHAPTER 1: to evaluate how the LM and the SC would affect the chemical degradation, through the softening test, of two nanohybrids; a 1st and a 2nd generation ormocer. Disk specimens (4 mm x 2 mm) were prepared from each material and light-activated by full-cure (F) and soft-start (S) modes. Four storage conditions were evaluated (n=5): group 1: immediately after cure, group 2: dry and dark, group 3: absolute ethanol and group 4: distilled water. Knoop hardness values (KHN) were measured immediately after cure and after immersion in the different SC for 24 hours. Two-way ANOVA with Tukey¿s post-hoc test (p = 0.05) was used to compare KHN among each SC and between the two LM. The LM presented no significant effect on the softening test, in all groups. However, significant differences were observed among the SC. Absolute ethanol produced the higher softening effect in all materials tested. The 2nd generation ormocer was the more stable material when stored in water. LM did not affect the final KHN. CHAPTER 2: to investigate the effect of filler-particle size of resin-composites, undergoing toothbrush abrasion (TA), on three surface properties: surface roughness (SR), surface gloss (G) and color stability (CS). Four models and one commercial resin-composite and with varying filler-size from 100 to 1000 nm were examined. Six discs (10 mm x 2 mm) from each - 0.97). Filler size did not affect CS. product were mechanically polished. The samples were then submitted to 20,000 brushing strokes in a TA machine. SR parameters (Ra, Rt and RSm), G and CS (CIE-L*a*b*) were measured before and after TA. Changes in SR and G were analyzed by 2-way ANOVA, with Bonferroni post-hoc test. CS values were submitted to one-way ANOVA and Bonferroni post-hoc test (p=0.05). There was no statistically significant difference in CS. TA resulted in rougher and matte surfaces for all materials tested. Although the individual differences in SR among filler sizes were not always significant, the correlation showed a trend that larger filler sizes result in higher surface roughness after abrasion for Ra and Rt parameters (r = 0.95; r = 0.93, respectively). RSm showed an increase after TA for all resin-composites; however no significant correlation was detected. Initial G values ranged between 73 and 83 gloss units (GU) and were reduced after TA to a range of 8.5 to 64 GU. TA revealed significant modifications in surface roughness and gloss amongst the materials tested, that related to filler sizes. There was a significant correlation between gloss and roughness (Ra) (r = ) - 0.97). Filler size did not affect CSDoutoradoDentísticaDoutor em Clínica Odontológic

Shrinkage Stresses Generated during Resin-Composite Applications: A Review

Many developments have been made in the field of resin composites for dental applications. However, the manifestation of shrinkage due to the polymerization process continues to be a major problem. The material's shrinkage, associated with dynamic development of elastic modulus, creates stresses within the material and its interface with the tooth structure. As a consequence, marginal failure and subsequent secondary caries, marginal staining, restoration displacement, tooth fracture, and/or post-operative sensitivity are clinical drawbacks of resin-composite applications. The aim of the current paper is to present an overview about the shrinkage stresses created during resin-composite applications, consequences, and advances. The paper is based on results of many researches that are available in the literature

ACERTOS GRADIENTES NOS CHAMADOS ERROS DE PRONÚNCIA

A proposta deste artigo é discutir o papel dos acertos gradientes no processo de estabelecimento de contrastes fônicos em crianças com os chamados “erros” de pronúncia, falantes do Português Brasileiro. As investigações pautaram-se principalmente pela análise acústica, à luz da Fonologia Acústico-Articulatória. os resultados compreendem um estudo transversal – com foco nas fricativas coronais desvozeadas – e dois estudos longitudinais – um com foco nos róticos e outro com foco nas obstruintes coronais desvozeadas. Ante a constatação de que os acertos gradientes permeiam a aquisição de contrastes fônicos muito mais do que se costuma imaginar, as implicações clínicas desses achados são debatidas

UFUS Riqueza: a new soybean cultivar for the state of Minas Gerais.

The release of cultivars has ensured higher yield associated with increased tolerance to climatic adversity. ‘UFUSRiqueza’ is resistant to natural dehiscence and to the diseases: bacterial pustule, downy mildew, frogeye leaf spot, brown stem rot,stem canker and stem necrosis and can reach yields of 3475 kg ha-1, with grain contents of 18 % oil and 39 % protein

Nutritional composition of bioproducts generated from semi-solid fermentation of pineapple peel by edible mushrooms

Mushroom production is a very efficient alternative to agro-industrial residues recycling. The proximal composition, content of macro and micro minerals, amino acid and proteolytic activity were assessed in the pineapple peel and in the bioproducts generated from pineapple peel and mycelium of Pleurotus albidus, Lentinus citrinus and Pleurotus florida. The bioproducts were obtained by semi-solid fermentation and drying process. Nutritional analysis was performed following standard methodologies. The data showed that the percentage of protein and minerals of the bioproducts increased and the carbohydrate content reduced after the myceliation by the mushrooms. All essential amino acids were found in the bioproducts and no contamination was observed. There was significant difference between proteolytic activities of bioproducts samples, presenting L. citrinus’ bioproduct a higher value. These data show that the bioproducts produced have great nutritional value and can be used as an alternative food.Key words: By-production, fermentation, mushroom, pineapple, protease

Evaluation of conjunctival bacterial flora in patients with Stevens-Johnson Syndrome

OBJECTIVE: To determine the conjunctival bacterial flora present in patients with Stevens-Johnson syndrome. METHODS: A prospective study of the conjunctival bacterial flora was performed in 41 eyes of 22 patients with Stevens-Johnson syndrome. The information gathered included the patient's sex and age, the duration of disease, the cause of Stevens-Johnson syndrome, and treatments. Scrapings of the inferior conjunctival fornix were performed in both eyes. Fourteen days before scraping, the patients were asked to interrupt all topical medication and start using 0.5% nonpreserved methylcellulose. The microbiological evaluation included microorganism identification and determination of antibiotic sensitivity. RESULTS: Of 22 patients (41 eyes), 14 (64%) were females, and eight (36%) were males. The mean age was 33.2 years, and the mean duration of disease was 15.6 years. Visual acuity ranged from light perception to 20/25 (1.57 logMar). The treatment received by most patients consisted of tear substitutes, topical antibiotics, and contact lenses. Bacterial identification was positive in 39 eyes (95%) and negative in two eyes (5%). Gram-positive cocci accounted for 55.5% of the microorganisms, whereas gram-positive bacilli and gram-negative bacilli accounted for 19% and 25.5%, respectively. Half of the patients (54%) had multiple bacterial species in their flora, and only one bacterial species was identified in the other half. Resistant bacteria were isolated from four eyes. The antibiotic sensitivity results for the Streptococcus group showed the lowest sensitivity and the highest microbial resistance identified. CONCLUSION: Patients with Stevens-Johnson syndrome have a diverse conjunctival flora that includes many pathogenic species.Federal University of São Paulo Vision Institute Ophthalmology DepartmentUNIFESP, Vision Institute Ophthalmology DepartmentSciEL

Evaluation of conjunctival bacterial flora in patients with Stevens-Johnson Syndrome

OBJECTIVE: To determine the conjunctival bacterial flora present in patients with Stevens-Johnson syndrome. METHODS: A prospective study of the conjunctival bacterial flora was performed in 41 eyes of 22 patients with Stevens-Johnson syndrome. The information gathered included the patient's sex and age, the duration of disease, the cause of Stevens-Johnson syndrome, and treatments. Scrapings of the inferior conjunctival fornix were performed in both eyes. Fourteen days before scraping, the patients were asked to interrupt all topical medication and start using 0.5% nonpreserved methylcellulose. The microbiological evaluation included microorganism identification and determination of antibiotic sensitivity. RESULTS: Of 22 patients (41 eyes), 14 (64%) were females, and eight (36%) were males. The mean age was 33.2 years, and the mean duration of disease was 15.6 years. Visual acuity ranged from light perception to 20/25 (1.57 logMar). The treatment received by most patients consisted of tear substitutes, topical antibiotics, and contact lenses. Bacterial identification was positive in 39 eyes (95%) and negative in two eyes (5%). Gram-positive cocci accounted for 55.5% of the microorganisms, whereas gram-positive bacilli and gram-negative bacilli accounted for 19% and 25.5%, respectively. Half of the patients (54%) had multiple bacterial species in their flora, and only one bacterial species was identified in the other half. Resistant bacteria were isolated from four eyes. The antibiotic sensitivity results for the Streptococcus group showed the lowest sensitivity and the highest microbial resistance identified. CONCLUSION: Patients with Stevens-Johnson syndrome have a diverse conjunctival flora that includes many pathogenic species

A importância da idade na síndrome metabólica em pacientes portadoras de ovários policísticos

This study aims to evaluate the prevalence and individual characteristics of the metabolic syndrome (MBS) in sergipanas women with polycystic ovary syndrome (PCOS) using age as an association variable. It is a cross-sectional study involving 50 women aged 25-50 years old with PCOS in accord with Rotterdam criteria (2003). For the diagnosis of metabolic syndrome, the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) was considered. The prevalence of the MBS was 56%. As for the individual components of MS, was evident: abdominal circumference > 88 cm in 72%, triglycerides ≥ 150 mg/dL in 32%, HDL-cholesterol <50 mg/dl in 54%, fasting glucose ≥ 110 mg/dl in 26%, systolic blood pressure ≥ 130 mmHg in 52% and diastolic blood pressure ≥ 85 mmHg in 40%. Patients aged equal or over 35 years had a higher percentage of Abdominal Circumference (AC) > 88 cm (40%), modified triglyceride levels (20%), HDL-cholesterol to levels below 50 mg/dl (34%), altered levels of fasting glucose (22%), systolic blood pressure (SBP) equal to or above 130 mmHg (36%) and diastolic blood pressure (DBP) equal to or above 85 mmHg (26%). There was a statistically significant association (p <0.05) between age and the following variables: AC, triglycerides, fasting glucose and DBP. There was a significant prevalence of MS in more than half the women studied, indicating increased chances for developing cardiovascular disease (CVD) and pointing out the need for tracking cardiovascular risk among women with clinical manifestations of PCOS

In vitro analysis of the pH stability of dental bleaching gels during in-office procedures

Previous studies have shown that acidic bleaching gels could lead to worse collateral effects during an in-office bleaching procedure, while neutral or basic products leads towards a better experience. Considering this fact, the main purpose of this stud