Mango peel as a potential enzyme inducer in Trichoderma harzianum: a strategy for cariogenic biofilm degradation and reuse of industrial waste

Water-insoluble exopolysaccharides (I-EPS) are a virulence factor for dental biofilms. It has already been demonstrated that mango pulp induces the secretion of glucan-hydrolytic enzymes in the fungus Trichoderma harzianum, and that they have an effect on I-EPS from young biofilms. Aim: Evaluate the effect of mango peel as an enzyme inducer in T. harzianum, and the effect of enzymes secreted on mature biofilms. Methods: Fractions of the peel (PL) and ethanol-precipitated pulp (PP) of Tommy Atkins mangoes were sterilized and added to a culture medium containing T. harzianum for induction of hydrolytic enzymes. After 192 h, the culture medium was centrifuged and the supernatant (enzyme extract) was used as treatment on S. mutans biofilms (n=9): a) NaCl 0.9 %; b) 0.12 % chlorhexidine digluconate; and c) extract of enzymes induced by PL or PP. Acidogenicity, bacterial viability, quantification of insoluble polysaccharides, and three-dimensional analysis of the biofilm by scanning electron microscopy (SEM) was performed. Data were analyzed by ANOVA followed by the Tukey test (α=5 %). Results: The hydrolytic enzymes did not alter the metabolism or bacterial viability of the biofilm (p<0.05). Although the images obtained by SEM suggest some degree of matrix degradation, the quantification of I-EPS for the PL and PP groups did not differ from the control group (p>0.05), suggesting a slight effect on the disorganization of the mature S. mutans biofilm. Conclusion: The results suggest that mango peel fraction can induce secretion of mutanase by T. harzianum, however in an insufficient amount to generate significant degradation on cariogenic biofilm.

Quantification of Streptococcus mutans in Different Types of Ligature Wires and Elastomeric Chains

Abstract This study aimed to test the hypothesis that Streptococcus mutans contamination levels differ according to the type of the orthodontic ligature. Thirteen patients were selected. Each quadrant was randomly subjected to one of the following ligature-use protocols: I) elastomeric chain, II) steel ligature crossed over the archwire, III) steel ligature crossed under the archwire, and IV) steel ligature in a figure-eight pattern under the archwire. After seven days, the devices were removed and the Streptococcus mutans colony-forming unit count per mg of biofilm weight was determined. Twelve specimens (n=3) were also processed for scanning electron microscopy analysis. ANOVA and Tukey-Kramer test were used for comparisons to assess S. mutans differences between groups at a 5% significance level. There was no statistical difference in detectable levels of S. mutans among the groups (p=0.294). Scanning electron microscopy results showed abundant biofilms and microbial contamination in all groups. In conclusion, S. mutans contamination levels are similar in the different orthodontic ligatures.

Resumo Este estudo teve como objetivo testar a hipótese de que os níveis de contaminação de Streptococcus mutans diferem de acordo com o tipo de ligadura ortodôntica. Treze pacientes foram selecionados. Cada quadrante foi submetido aleatoriamente a um dos seguintes protocolos de uso de ligadura: I) ligadura elastomérica, II) ligadura de aço trançada sobre o arco, III) ligadura de aço trançada sob o arco e IV) ligadura de aço em um padrão de "oito" sob o arco. Após sete dias, os dispositivos foram removidos e a contagem das unidades formadoras de colônia de S. mutans por mg de peso de biofilme foi determinada. Doze espécimes (n = 3) também foram processados para análise por microscopia eletrônica de varredura. Análise de variância e teste de Tukey-Kramer foram utilizados para comparações a fim de avaliar as diferenças de níveis de S. mutans entre os grupos com significância de 5%. Não houve diferença estatisticamente significante em níveis detectáveis de S. mutans entre os grupos (p = 0,294). Os resultados da microscopia eletrônica de varredura mostraram biofilmes abundantes e contaminação microbiana em todos os grupos. Em conclusão, os níveis de contaminação de S. mutans são semelhantes nas diferentes ligaduras ortodônticas.

Teaching of bioethics in dental graduate programs in Brazil

In the field of human research, researchers are faced with unexpected moral dilemmas, as a result of the development of technologies applied to health. Due to the great importance of this issue, our objective was to evaluate bioethics instruction in the education of researchers in Brazilian graduate programs in dentistry. Eighty-seven graduate programs in dentistry, recognized by CAPES (Coordination for the Improvement of Higher Education Personnel) were evaluated in this study. Data were extracted independently by two researchers from the CAPES website, and from the websites of the graduate programs, directly or via links to the programs available at the CAPES website. Forty-eight out of 87 programs had an ethics/bioethics course as part of their curricula. Of the graduation programs graded 5, 6 or 7 by CAPES, 38 percent included bioethics courses, while 62 percent of the programs graded 3 or 4 by CAPES had bioethics courses as part of their curricula. These findings are an alert to those involved in dental research education, as they showed that, although resolution 196/96 by the National Council of Health regulating human research in Brazil was published ten years ago, bioethics instruction in Brazilian graduate programs in dentistry is still at an incipient stage. This situation indicates a need for ethics pedagogy in the education of young researchers.

O desenvolvimento de tecnologias aplicadas à saúde traz dilemas morais inesperados aos profissionais de pesquisa, em relação às práticas que envolvem seres humanos. Devido à relevância deste assunto, o objetivo deste estudo foi avaliar o ensino de bioética na educação de estudantes de programas de pós-graduação em Odontologia do Brasil. Oitenta e sete programas de pós-graduação em Odontologia, avaliados pela CAPES (2001-2003), foram estudados. Os dados foram extraídos, de maneira independente, por 2 avaliadores, por meio de consulta ao sítio da CAPES e aos sítios eletrônicos dos programas, diretamente ou via links dos programas disponíveis no sítio da CAPES. Dos 87 programas, 48 apresentaram disciplina de Ética/Bioética. Trinta e oito porcento dos programas com conceitos 5, 6 e 7 da CAPES mantêm disciplinas de Bioética, enquanto 62 por cento dos programas com conceitos 3 e 4 apresentaram conteúdos de Bioética. Desta forma, os resultados deste estudo representam um alerta para os educadores envolvidos em ensino da pesquisa odontológica. Estes resultados também mostraram que a instrução em bioética ainda é incipiente nos programas de pós-graduação em Odontologia no Brasil, ainda que a resolução 196/96 do Conselho Nacional de Saúde tenha sido publicada há dez anos. Por este motivo, seria necessário assegurar uma pedagogia ética na formação do jovem pesquisador.