Statins and oral biofilm: Simvastatin as a promising drug to control periodontal dysbiosis.

OBJECTIVES: This study evaluated antimicrobial activity of atorvastatin, pravastatin, rosuvastatin, and simvastatin against oral bacteria, and the interaction of simvastatin with standard antimicrobials (amoxicillin and metronidazole). METHODS: Minimal inhibitory concentration assays were performed with Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Actinomyces odontolyticus, Streptococcus oralis, Streptococcus mitis, Streptococcus salivarius, Streptococcus sanguinis, and Streptococcus gordonii; checkerboard microdilution assays between simvastatin and standard antimicrobials; monospecies and multispecies biofilms. RESULTS: Simvastatin showed the best antimicrobial activity against most species (MIC range from 3.12 to 25 µg/ml), highlighting the sensitivity of P. gingivalis. In the checkerboard assay, synergistic interaction was found between simvastatin and amoxicillin against S. oralis and S. sanguinis. P. gingivalis biofilm was inhibited by simvastatin at 10 and 50× Minimal inhibitory concentration, with similar effects to metronidazole. For multispecies biofilm, SMV reduced the biofilm metabolic activity (79%) and total counts (87%), comparable to amoxicillin. Simvastatin also reduced bacterial counts of Veilonnella parvula, P. gingivalis, Streptococcus mutans, Actinomyces naeslundii, P. intermedia, and Capnocytophaga ochracea in the multispecies biofilm. CONCLUSIONS: Simvastatin showed antimicrobial and antibiofilm activity against oral bacteria and may contribute to the control of dysbiosis, and may be considered in clinical studies as an adjuvant in the treatment of periodontitis.

A puzzle used to teach the cardiac cycle.

The aim of the present article is to describe a puzzle developed for use in teaching cardiac physiology classes. The puzzle presents figures of phases of the cardiac cycle and a table with five columns: phases of cardiac cycle, atrial state, ventricular state, state of atrioventricular valves, and pulmonary and aortic valves. Chips are provided for use to complete the table. Students are requested to discuss which is the correct sequence of figures indicating the phases of cardiac cycle. Afterward, they should complete the table with the chips. Students of biology, dentistry, medicine, pharmacy, and nursing graduation courses from seven institutions performed the puzzle evaluation. They were invited to indicate whether the puzzle had been useful for learning about the subject by filling one of four alternatives. Of the students, 4.6% answered that it was not necessary but helped them to confirm what they had learned, 64.5% reported that although they had previously understood the cardiac cycle, the puzzle helped them to solve doubts and promoted a better understanding of it, and 30.9% said that they needed the puzzle to understand the cardiac cycle, without differences among courses, institutions, and course semesters. The results of the present study suggest that a simple and inexpensive puzzle may be useful as an active learning methodology applied after the theoretical lecture, as a complementary tool for studying cardiac cycle physiology.

Active learning methodology, associated to formative assessment, improved cardiac physiology knowledge and decreased pre-test stress and anxiety.

Stress and anxiety caused by assessments are often related to the student's insecurity regarding the knowledge to be evaluated, while teaching strategies that increase effective learning can assist in reducing it. The aim of this study was to evaluate the hypothesis that the use of an active methodology, associated to formative assessment, could reduce students' anxiety and stress, when compared to the traditional method, by promoting greater learning. New students enrolled in the same discipline of a Dentistry course were invited to participate in the study and were divided into two groups: traditional method and active methodology. The traditional method group received two lectures, delivered orally. The active methodology group received a lecture about cardiac cells and the autonomic control of cardiac function, with home study of the cardiac cycle using a textbook. In the second class, an individual formative assessment was applied. Afterwards, a group activity was performed with an educational game about the cardiac cycle, followed by a group formative assessment. After applying the traditional or active methodology, test 1 was carried out. Immediately before this test, saliva samples were collected for determination of the concentrations of the stress biomarkers cortisol and α-amylase. The students also answered the State-Trait Anxiety Inventory questionnaire, used for anxiety level determination. The score obtained in the test 1 was significantly higher for the active methodology group, compared to the traditional method group. No significant differences between the groups were observed for baseline cortisol and salivary α-amylase concentrations, or for anxiety scores. Before test 1, traditional method group presented higher concentrations of salivary cortisol and α-amylase, compared to the respective baseline values, while the active methodology group showed no difference between the baseline and test 1 levels. Before test 1, there were increases in anxiety levels, relative to the respective baseline values, regardless of the teaching methodology used, but this increase was greater for the traditional method group, compared to the active methodology group. These results showed that the active methodology, associated to formative assessment, decreased test stress and anxiety, with improved student performance in comparison to traditional lectures.

Statins with potential to control periodontitis: From biological mechanisms to clinical studies.

BACKGROUND: Statins are widely used for the treatment of hyperlipidemia. However, these drugs have pleiotropic effects that can be promising for the prevention and treatment of oral diseases, such as periodontitis. HIGHLIGHT: This review aimed to identify preclinical, observational, and clinical studies that evaluate the effects and biological mechanisms of statins on oral cells and tissues and those using these drugs to treat periodontitis. A literature survey has been conducted in PubMed using combinations of the uniterms: "statins," "dentistry," "periodontal disease," and "periodontal treatment." In vitro findings showed positive statin results in cell lines related to alveolar bone metabolism by altering the signaling pathway Osteoprotegerin/Receptor Activator of Nuclear Factor Kappa B/Receptor Activator of Nuclear Factor Kappa B Ligand (OPG/RANK/RANKL), stimulating the production of alkaline phosphatase and osteocalcin, and reducing the production of matrix metalloproteinases (MMPs). Animal studies have shown a reduction in alveolar bone loss and osteoclastic activity, in addition to a reduction in inflammatory markers, such as IL-1, IL-6, and TNF-α, when statins were used prophylactically. Clinical trials showed a positive impact on clinical parameters, leading to a higher reduction in probing depth and gain in clinical attachment when a local statin was adjunctively associated with mechanical therapy. CONCLUSION: Statins were shown to be promising for regenerating and stimulating bone activity, with great potential for treating chronic periodontitis. However, further studies are required to confirm its effectiveness.

Effects of academic stress on the levels of oral volatile sulfur compounds, halitosis-related bacteria and stress biomarkers of healthy female undergraduate students.

To investigate whether academic stress changes the salivary microbiota and its relationship with salivary parameters, evaluating the effects on the production of volatile sulfur compounds (VSCs) in healthy women. Fifty-five women who were enrolled in a four-year Dentistry course were assessed for academic stress by the questionnaire Maslach Burnout Inventory-Student Survey and were then classified into 'Not Stressed' and 'Stressed' groups. Cortisol and alpha-amylase (AA) were measured as physiological stress biomarkers. Oral Chroma™ gas chromatograph was used to measure concentrations of hydrogen sulfide (H2S), methyl mercaptan and dimethyl sulfide. Salivary proteins were evaluated by western blot. Quantitative polymerase chain reaction was used to identify the salivary amounts of halitosis-associated bacteria. The 'Stressed' volunteers showed higher levels of H2S, AA, Fusobacterium nucleatum and total bacteria, compared to the 'Not Stressed' individuals (p < 0.05; Mann-Whitney test). Salivary proteins showed no differences between groups (p > 0.05; Mann-Whitney test). Academic stress was positively correlated with H2S, total bacteria and F. nucleatum counts, while F. nucleatum was positively correlated with AA. H2S showed positive correlations with AA and Solobacterium moorei (p < 0.05; Spearman correlation). Beta-defensin (BD) presented negative correlations with H2S and S. moorei (p < 0.05; Spearman correlation). Academic stress increased salivary F. nucleatum and total bacteria, as well as AA activity. The protein BD showed important correlations with bacteria and VSC. These changes appeared to be accountable for increased H2S production in the stressed women.