25 research outputs found
Ethical considerations about authorship of scientific papers
O texto alerta para a consciência da relação ética da produção intelectual no que refere a quantidade, qualidade, autoria e publicação. Reafirma a importância da questão ética do gerenciamento de grupos de trabalho e a efetiva participação no desenvolvimento do projeto experimental.This article stresses the importance of ethical relations involved in intellectual production, particularly as regards quantity, quality, authorship and publication. It reaffirms the importance of ethics while managing workgroups, and the effective participation in the development of experimental projects
Mechanical-physicochemical properties and biocompatibility of catechin-incorporated adhesive resins
Several anti-proteolytic dentin therapies are being exhaustively studied in an attempt to reduce dentin bond degradation and improve clinical performance and longevity of adhesive restorations. Objectives: This study assessed the effect of epigallocatechin-3-gallate (EGCG) on long-term bond strength when incorporated into adhesives. Material and Methods: Adhesive systems were formulated with EGCG concentrations of 0 wt%: (no EGCG; control); 0.5 wt% EGCG; 1.0 wt% EGCG, and 1.5 wt% EGCG. Flexural strength (FS), modulus of elasticity (ME), modulus of resilience (MR), compressive strength (CS), degree of conversion (DC), polymerization shrinkage (PS), percentage of water sorption (%WS), percentage of water solubility (%WL) and cytotoxicity properties were tested. Dentin microtensile bond strength (µTBS) was evaluated after 24 h and again after 6 months of water storage. The adhesive interface was analyzed using scanning electron microscopy (SEM). Results: No significant differences were found among the groups in terms of FS, ME, MR, CS and PS. EGCG-doped adhesives increased the DC relative to the control group. EGCG concentrations of 1.0 wt% and 0.5 wt% decreased the WS of adhesives. WL decreased in all cases in which EGCG was added to adhesives, regardless of the concentration. EGCG concentrations of 1.0 wt% and 0.5 wt% reduced cytotoxicity. EGCG concentrations of 1.0 wt% and 0.5 wt% preserved µTBS after 6 months of storage, while 1.5 wt% EGCG significantly decreased µTBS. SEM: the integrity of the hybrid layer was maintained in the 0.5 wt% and 1.0 wt% EGCG groups. Conclusion: EGCG concentrations of 1.0 wt% and 0.5 wt% showed better biological and mechanical performance, preserved bond strength and adhesive interface, and reduced cytotoxicity
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Human pulp fibroblasts response to substances leached from direct pulp capping materials
Cavalcanti, BN. Resposta de fibroblastos de polpa humanos frente a substâncias liberadas por capeadores pulpares diretos [Tese de Doutorado]. São Paulo: Faculdade de Odontologia da USP; 2003. RESUMO O objetivo do presente estudo foi o de avaliar os efeitos citotóxicos de substâncias liberadas durante a aplicação de materiais utilizados em capeamento pulpar direto, sobre fibroblastos de polpa dentária humana. Utilizou-se para o experimento meios condicionados pelas substâncias a serem testadas, divididas nos grupos a seguir: grupo I: controle (meio de cultivo sem condicionamento); grupo II: cimento de hidróxido de cálcio; grupo III: adesivo dentinário; grupo IV: ácido ortofosfórico a 37%. O condicionamento foi realizado, colocando-se meio de cultivo fresco sobre os materiais de modo que a presa (grupo II), polimerização (grupo III) ou o contato direto (grupo IV) liberassem substâncias para esse meio de cultivo. Esse meio era colocado sobre as células durante todo o experimento, excetuando-se o grupo IV, onde o contato foi feito por um período de 15 segundos, conforme recomendações clínicas. Posteriormente foram realizadas contagens em hemocitômetro pelo método de exclusão por azul de Trypan, que cora somente as células mortas. As contagens foram realizadas em períodos de 0, 6, 12 e 24 horas para o experimento de viabilidade celular (curto prazo), onde se avaliou o percentual de células vivas sobre o total de células, e em períodos de 1, 3, 5 e 7 dias para o experimento de sobrevivência celular, no qual se avaliou o número absoluto de células vivas. Observou-se que as substâncias liberadas pelo adesivo dentinário são citotóxicas em qualquer período, diminuindo consideravelmente a viabilidade celular e afetando suas curvas de crescimento. Aquelas liberadas pelo ácido ortofosfórico a 37% provocam diminuição da viabilidade somente nos primeiros momentos do contato com as células, enquanto as substâncias liberadas durante a presa do hidróxido de cálcio não são citotóxicas em nenhum momento.The purpose of the present study was to evaluate the cytotoxic effects of substances leached during the use of direct pulp capping materials, on human pulp fibroblasts. There were used cell culture mediums conditioned by the test materials, as follows: group I: control (fresh medium without conditioning); group II: calcium hydroxide cement; group III: bonding system; group IV: 37% orthophosphoric acid. The medium conditioning was made, pouring the fresh conditioning medium on the materials, in order that its setting (group II), polymerization (group III) or the direct contact (group IV) would be able to leach substances to this culture medium. These conditioned mediums were put on the cells for the entire experiment, excepting the group IV, in which the mediums were put in contact with the cells for 15 seconds, following clinical recommendations. Cell counting was performed in hemocytometer, using the Trypan blue exclusion method, which mark only the dead cells. These counting was made at experimental times of 0, 6, 12 and 24 hours for the cell viability assay (short term), where it is evaluated the percentage of live cells on the total number of cells, and at experimental times of 1, 3, 5 and 7 days for the survival assay, in which is evaluated the absolute number of live cells. It was observed that the substances leached by the bonding system are cytotoxic at all experimental times, decreasing significantly the cell viability and affecting its growing rate. Those leached by the 37% orthophosphoric acid decreased the cell viability only at the first contact with the cells, and the substances leached during the setting of the calcium hydroxide cement are not cytotoxic
Comparação termométrica entre preparos cavitários realizados com turbinas de alta-rotação e laser de Er:YAG
The aim of this study was to compare temperature increases produced by a well-known equipment, the high-speed handpieces, with a relatively new instrument, the Er:YAG laser (350 mJ/10 Hz). Thirty-five bovine mandibular incisors, which were reduced to an enamel/dentin thickness of 2,5 mm, were used. Cavity preparation was done till a depth of 2, 5 mm. A thermocouple was placed to read the temperature inside of the pulp chamber. Analysis was performed in these groups: I - high-speed handpiece without water-cooling (n=10); II - high-speed handpiece with water-cooling (n=10); III - Er:YAG laser without water-cooling (n=5); IV- Er:YAG laser with water-cooling (n=10) Group III had only 5 teeth because it was impossible to properly make the cavity preparations by the laser equipment without water cooling. The temperature increases were recorded in a computer linked to the thermocouples and the data of the groups I, II and IV were submitted to Dunn's multiple comparison test (p<0,05). The medium temperature increases were: 11,64ºC for group I, 0,96ºC for group II, 40,86ºC for group III and 2,9°C for group IV. There were no statistical differences between groups lI and IV, and these were different from group I. The cavity preparations made by the high-speed and the laser equipment generated very similar heat increases under water-cooling. The water-cooling is essential to avoid aggressive temperature increases, both when using the high-speed and the laser equipment, and with laser it is especially necessary for ablation of enamelO objetivo deste estudo foi comparar as variações de temperatura provocadas por turbinas de alta-rotação e pelo laser de Er:YAG (350mJ/10 Hz). Preparos cavitários classe V foram realizados numa profundidade de 2,0mm em 35 incisivos inferiores bovinos, que tiveram um termopar posicionado para ler as temperaturas no interior da câmara pulpar. A análise foi feita nos seguintes grupos: I - alta-rotação sem refrigeração a água; II - alta-rotação com refrigeração a água; III- laser de Er:YAG sem refrigeração a água; IV- laser de Er:YAG com refrigeração a água. Em todos os grupos foram utilizados dez dentes, com exceção do grupo III, que teve uma amostra de apenas cinco dentes, uma vez que foi impossível realizar os preparos adequadamente com o laser sem refrigeração. Os aumentos de temperatura foram gravados num computador ligados aos termopares e os dados dos grupos I, lI e IV foram submetidos ao teste de Dunn para comparações múltiplas (p<0,05). Os aumentos médios de temperatura foram: 11,64°C para o grupo I, 0,96°C para o grupo II, 40,86°C para o grupo lll e 2,9°C para o grupo IV. Não houve diferenças estatisticamente significantes entre os grupos II e IV, e estes foram diferentes do grupo I. Os preparos cavitários realizados com as turbinas de alta-rotação e com o laser de Er:YAG geraram aumentos de temperatura semelhantes quando sob refrigeração a água. A refrigeração é essencial para evitar aumentos de temperatura agressivos em ambos os casos e com o laser de Er:YAG é especialmente necessária para a ablação do esmalt
Biologia pulpar: da agressão à reparação
The study of the dental pulp can be extended from factors related to its aggression to those related to new concepts of regeneration. The purpose of this compilation of studies is to present the evolution of a research subject from damage to repair. Innitially, studies will demonstrate the ability of dental procedures to generate heat and consequently affect the dental pulp. In sequence, studies will also present some effects of different pulp capping materials on dental pulp cells, related to the cytotoxicity of these materials and inflammatory potential. Finally, as the subject is emmerging and gaining importance in the literature, this compilation will present data from recent studies on the role of dental pulp progenitor cells in the regeneration and repair of dental pulp, as well as an alternative for a scaffold that could be used for clinical translation of research in the field. In summary, dentists must be aware of these different aspects and that the knowledge on factors and mechanisms involved in the aggression of the dental pulp can also serve as basis for understanding aspects for regeneration.O estudo da polpa dentária pode se desdobrar desde fatores relacionados à sua agressão até àqueles relacionados a novos conceitos de regeneração. A proposta desta compilação de estudos é a de apresentar a evolução de uma linha de pesquisa desde a agressão até o reparo. Inicialmente, estudos demonstrarão a capacidade de procedimentos odontológicos em gerar calor e consequentemente afetar a polpa dental. Em sequência, estudos apresentarão alguns efeitos de diferentes materiais de capeamento pulpar em células da polpa dentária, relacionados à citotoxicidade e potencial inflamatório destes materiais. Finalmente, como um assunto emergente que vem ganhando importância na literatura, esta compilação apresentará dados de estudos recentes sobre o papel de células progenitoras na regeneração e reparo da polpa dentária, bem como uma alternativa de scaffold que pode ser utilizado para translação clínica da pesquisa neste campo. Em resumo, o profissional de odontologia deve estar atento para estes diferentes aspectos e para o fato de que o conhecimento de fatores e mecanismos envolvidos na agressão da polpa dentária podem também servir de base para o entendimento dos aspectos da regeneração
Evaluation of the use of an injectable matrix for tissue engineering of dental pulp
Dental pulp is a highly specialized mesenchymal tissue, which have a restrict regeneration capacity due to anatomical arrangement and post-mitotic nature of odontoblastic cells. Entire pulp amputation followed by pulp-space disinfection and filling with an artificial material cause loss of a significant amount of dentin leaving as life-lasting sequelae a non-vital and weakened tooth. However, regenerative endodontics is an emerging field of modern tissue engineering that demonstrated promising results using stem cells associated with scaffolds and responsive molecules. Thereby, this article will review the most recent endeavors to regenerate pulp tissue based on tissue engineering principles and providing insightful information to readers about the different aspects enrolled in tissue engineering. Here, we speculate that the search for the ideal combination of cells, scaffolds, and morphogenic factors for dental pulp tissue engineering may be extended over future years and result in significant advances in other areas of dental and craniofacial research. The finds collected in our review showed that we are now at a stage in which engineering a complex tissue, such as the dental pulp, is no longer an unachievable and the next decade will certainly be an exciting time for dental and craniofacial research
Puramatrix: An injectable scaffold for dental pulp tissue engineering.
The clinical translation of stem cell-based Regenerative Endodontics demands further development of suitable injectable scaffolds. Puramatrix™ is a defined, self-assembling peptide hydrogel which instantaneously polymerizes under normal physiological conditions. Here, we assessed the compatibility of Puramatrix™ with dental pulp stem cell (DPSC) growth and differentiation