Halitosis is an unpleasant change of breath due to volatile sulfur compounds (VSC) production originated from bacterial metabolism on the amino acid degradation. Menstrual cycle and pre-menstrual syndrome can change oral homeostasis and influence on VSC production. Although over 90% of bad breath cases are due to oral bacteria activities, anxiety and stress have been suggested as possible etiologic agents that cause halitosis. In previous study, we observed that stress reduced beta-defensin (BD) concentration, an antimicrobial peptide that plays an important role in innate defense response. Therefore, the aim of the present study is to determine the oral microbiota profile in oral healthy patients that presented some level of stress; to evaluate the influence of beta-defensin (BD) and female sex hormones estradiol (E) and progesterone (P) on bacterial growth and production of VSC from microorganisms determined in the first part of the present study. Saliva samples of stressed and non-stressed undergraduate students from Dentistry course (samples previously collected in a prior study) will be evaluated regarding six VSC - bacterial species producing, by PCR-real time. Furthermore, two of the bacterial species, which present higher amounts in saliva samples, will be selected for the study of the treatment effects with BD, E and P on growth and viability on planktonic culture. In addition, gas chromatography (Oral Chroma®) will be performed to measure the VSC released direct from culture tubes, to evaluate the effect of BD, E and P on VSC production by these microorganisms.
News published in Agência FAPESP Newsletter about the scholarship: