Effect of bioactive glasses containing strontium and potassium on dentin permeability.

Dentin hypersensitivity (DH) is characterized by pain caused by an external stimulus on exposed dentin. Different therapeutic approaches have been proposed to mitigate this problem; however, none of them provide permanent pain relief. In this study, we synthesized and characterized experimental bioactive glasses containing 3.07 mol% SrO or 3.36 mol% K2 O (both equivalent to 5 wt% in the glass), and evaluated their effect on dentin permeability to verify their potential to treat DH. The experimental materials were characterized by field-emission scanning electron microscopy, Fourier transform infrared spectroscopy, micro-Raman spectroscopy, and X-ray diffraction to confirm the respective structures and chemical compositions. The reduction in the hydraulic conductance of dentin was evaluated at the three stages: minimum permeability; maximum permeability (24% ethylenediaminetetraacetic acid [EDTA] treatment); and final dentin permeability after treatment with the bioactive glasses. They all promoted a reduction in dentin permeability, with a significant difference for each sample and posttreatment group. Also, a significant reduction in dentin permeability was observed even after a simulated toothbrushing test, demonstrating effective action of these materials against DH. Besides, incorporating 3.07 mol% SrO was a positive factor. Therefore, strontium's desensitizing and re-mineralizing properties can be further exploited in bioactive glasses to promote a synergistic effect to treat DH.

Laser de baixa intensidade como terapia auxiliar no tratamento periodontal ­ relatos de casos / Low level LASER an auxiliary therapy in periodontal treatment - case reports

Este estudo se propôs a analisar a efetividade do uso do LASER como terapias auxiliares em conjunto com a terapia periodontal básica, e compará-las com o resultado clínico periodontal e microbiológica em relatos de dois casos de periodontite crônica. Após os exames iniciais foi realizado a terapia periodontal básica, raspagem e alisamento radicular em todos quadrantes e posteriormente foram divididos aleatoriamente para aplicação das técnicas terapêuticas auxiliares, as quais eram aplicação do LASER de baixa intensidade, aplicação do LASER de baixa intensidade com o fotoiniciador azul de metileno e gel de clorexidina a 2%. Na coleta microbiológica quando comparado o início e o período da reavaliação periodontal houve redução dos Gram negativos e análises clínicas no índice de sangramento gengival, índice de placa, profundidade de sondagem. Com uma diminuição dos quadros inflamatórios referente ao índice de sangramento, a mobilidade dental apresentou relativa melhora ao tratamento, entretanto em relação a profundidade de sondagem não houve diferença entre as técnicas realizadas. Na análise microbiológica houve redução nos percentuais de crescimento bacteriano, quando realizado a contagem no número de micro-organismos Gram negativos por sítios em maior número quando associado o LASER com o fotoiniciador e o gel de clorexidina.Sugere-se que o LASER pode melhorar os parâmetros de inflamação periodontal, podendo ser aplicado como auxiliar a terapia periodontal básica, devendo ensaios clínicos serem realizados para um protocolo do uso do LASER em periodontite. (AU)

This study aimed to analyze the effectiveness of the use of LASER as ancillary therapies in conjunction with basic periodontal therapy, and to compare them with the clinical and periodontal and microbiological results in two cases of chronic periodontitis. After the initial exams, basic periodontal therapy, scaling and root planing were performed in all quadrants and were later randomly assigned to the application of the auxiliary therapeutic techniques, which were low intensity LASER application, low intensity LASER application with the blue photoinitiator methylene chloride and 2% chlorhexidine gel. In the microbiological collection, when comparing the beginning and the period of the periodontal reassessment, there was a reduction of the Gram negative and clinical analyzes in the index of gingival bleeding, plaque index, depth of probing. With a decrease of the inflammatory pictures referring to the bleeding index, the dental mobility showed a relative improvement in the treatment, however in relation to the depth of probing there was no difference between the techniques performed. In the microbiological analysis, the percentage of bacterial growth was reduced when counting the number of Gram negative microorganisms by sites in greater amount when associated with the LASER with the photoinitiator and the chlorhexidine gel. It is suggested that the LASER can improve parameters of periodontal inflammation and can be applied as an aid to basic periodontal therapy, and clinical trials should be performed for a protocol of LASER use in periodontitis. (AU)

Effect of the Bis-Dimethylamino Benzydrol Coinitiator on the Mechanical and Biological Properties of a Composite.

To examine the effect of the alternative coinitiator 4,4'bis dimethylamino benzydrol (BZN) in degree of conversion (DC), mechanical and biological properties of experimental composites. The coinitiator BZN was used in three concentrations (0.2, 0.5 and 1.2%), and the coinitiator DMAEMA was used as control at the same concentrations as above. The molar concentration of camphorquinone (CQ) and coinitiators was kept constant (1:1). The composites were manipulated and submitted to microhardness test (VHN), flexural and compressive strength (in MPa), elastic modulus (GPa), DC (FT-IR) and in vitro cytotoxicity (against 3T3 fibroblastic cells) of the experimental resins. Data were subjected to two-way ANOVA and Tukey post-test (α=0.05). The experimental composite resin with BZN showed higher DC values compared to control DMAEMA groups. For the mechanical properties, microhardness values were higher in BZN groups; flexural strength and elastic modulus were similar between all the groups. Compressive strength for groups BZN0.5 and DMAEMA0.5 were not statistically different, being the lowest values attributed to group BZN0.2. The experimental resins with BZN and DMAEMA were considered nontoxic against 3T3 fibroblasts. The inclusion of the coinitiator BZN in experimental composites was considered nontoxic against 3T3 fibroblast cells, without compromising DC and mechanical properties.

Effect of the Bis-Dimethylamino Benzydrol Coinitiator on the Mechanical and Biological Properties of a Composite

Abstract To examine the effect of the alternative coinitiator 4,4'bis dimethylamino benzydrol (BZN) in degree of conversion (DC), mechanical and biological properties of experimental composites. The coinitiator BZN was used in three concentrations (0.2, 0.5 and 1.2%), and the coinitiator DMAEMA was used as control at the same concentrations as above. The molar concentration of camphorquinone (CQ) and coinitiators was kept constant (1:1). The composites were manipulated and submitted to microhardness test (VHN), flexural and compressive strength (in MPa), elastic modulus (GPa), DC (FT-IR) and in vitro cytotoxicity (against 3T3 fibroblastic cells) of the experimental resins. Data were subjected to two-way ANOVA and Tukey post-test (α=0.05). The experimental composite resin with BZN showed higher DC values compared to control DMAEMA groups. For the mechanical properties, microhardness values were higher in BZN groups; flexural strength and elastic modulus were similar between all the groups. Compressive strength for groups BZN0.5 and DMAEMA0.5 were not statistically different, being the lowest values attributed to group BZN0.2. The experimental resins with BZN and DMAEMA were considered nontoxic against 3T3 fibroblasts. The inclusion of the coinitiator BZN in experimental composites was considered nontoxic against 3T3 fibroblast cells, without compromising DC and mechanical properties.

Resumo Analisar o efeito do co-iniciador alternativo 4,4'bisdimetilaminobenzidrol (BZN) no grau de conversão (GC) e nas propriedades mecânicas e biológicas de resinas compostas experimentais. O co-iniciador BZN foi utilizado em três concentrações (0,2, 0,5 e 1,2), e o co-iniciador DMAEMA como controle, nas mesmas concentrações acima. A concentração molar entre canforoquinona (CQ) e os co-iniciadores foi mantida constante (1:1). As resinas compostas foram manipuladas e submetidas aos testes de microdureza (VHN), resistência à compressão e flexural (em MPa), módulo de elasticidade (em GPa), GC (em %, por meio de espectroscopia micro-Raman e FTIR com KBr), citotoxicidade in vitro (frente às células fibroblásticas 3T3) das resinas experimentais. Os resultados foram submetidos ao teste ANOVA 1 fator e pós-teste de Tukey (α=0,05). As resinas compostas experimentais com o BZN apresentaram GC e propriedades mecânicas satisfatórias, além de serem consideradas atóxicas a fibroblastos 3T3. A inclusão do co-iniciador BZN à resina composta foi considerada não tóxica frente a células fibroblásticas 3T3 e sem comprometer o grau de conversão e as propriedades mecânicas da mesma.

A ética em pesquisa com seres humanos pelas lentes do cinema / Ethics in clinical research through movies

O avanço científico que vem ocorrendo no Brasil elevou a necessitada de discussão sobre ética em pesquisa envolvendo seres humanos dentro das instituições de ensino superior. Para isso, a associação entre a arte persuasiva do cinema e a ética em pesquisa tem sido uma metodologia eficaz no que diz respeito ao processo de ensino-aprendizagem de alunos de graduação e pós-graduação. Assim, o objetivo deste projeto de extensão foi promover a discussão e o conhecimento sobre a ética em pesquisa envolvendo seres humanos com graduandos, pós-graduandos, professores e servidores públicos da Universidade Estadual de Ponta Grossa. Os resultados mostraram a efetividade do método, concluindo que os filmes contribuíram satisfatoriamente para o aprendizado e posicionamento ético de todos os participantes (AU).

The scientific advance that has occurred in Brazil increases the need to discuss ethics in human research within universities and research institutes. With this in mind, the association between the persuasive art of cinema and ethics research has been an effective methodology regarding the teaching and learning of undergraduate and graduate students. The aim of this extramural education project was to promote the discussion and understanding of ethics in human clinical research among undergraduate and graduate students, professors and public servants at Ponta Grossa State University. The results showed the effectiveness of this method. In conclusion, movies can contribute satisfactorily to the ethical learning and positioning of all participants (AU).