Bacteria Residing at Root Canals Can Induce Cell Proliferation and Alter the Mechanical Properties of Gingival and Cancer Cells.

Understanding the importance of oral microbiota in human health and disease also leads to an expansion of the knowledge on functional, metabolic, and molecular alterations directly contributing to oral and systemic pathologies. To date, a compelling number of studies have documented the crucial role of some oral cavity-occurring microbes in the initiation and progression of cancers. Although this effect was noted primarily for Fusobacterium spp., the potential impact of other oral microbes is also worthy of investigation. In this study, we aimed to assess the effect of Enterococcus faecalis, Actinomyces odontolyticus, and Propionibacterium acnes on the proliferation capability and mechanical features of gingival cells and cell lines derived from lung, breast, and ovarian cancers. For this purpose, we incubated selected cell lines with heat-inactivated bacteria and supernatants collected from biofilms, cultured in both anaerobic and aerobic conditions, in the presence of surgically removed teeth and human saliva. The effect of oral bacteria on cell population growth is variable, with the highest growth-promoting abilities observed for E. faecalis in relation to human primary gingival fibroblasts (HGF) and lung cancer A549 cells, and P. acnes in relation to breast cancer MCF-7 and ovarian cancer SKOV-3 cells. Notably, this effect seems to depend on a delicate balance between the pro-stimulatory and toxic effects of bacterial-derived products. Regardless of the diverse effect of bacterial products on cellular proliferation capability, we observed significant alterations in stiffness of gingival and lung cancer cells stimulated with E. faecalis bacteria and corresponding biofilm supernatants, suggesting a novel molecular mechanism involved in the pathogenesis of diseases in oral cavities and tooth tissues. Accordingly, it is proposed that analysis of cancerogenic features of oral cavity bacteria should be multivariable and should include investigation of potential alterations in cell mechanical properties. These findings corroborate the important role of oral hygiene and root canal treatment to assure the healthy stage of oral microbiota.

Smoking Prevalence, Attitudes and Behavior among Dental Students in Poland and Italy.

The aim of the study was to perform preliminary research to compare the smoking prevalence, attitudes and behavior between dentistry students in two universities in Europe using the standardized Global Health Professions Student Survey (GHPSS) questionnaire. This was cross-sectional carried out among dentistry students from the Medical University in Bialystok, Poland and Sapienza University of Rome, Italy. There were 582 participants; 282 were Italians, 202 were smokers and 42% were Italians. The response rate was 79.9% of Italian students and 79.6% of Polish students. The prevalence of smoking was significantly higher among Italian students (42% vs. 28.0%). Attitudes and behaviour of smokers and non-smokers differed statistically. Polish and Italian dental students presented statistically different behavior regarding the time to smoke the first cigarette, the willingness to stop smoking and trying to stop smoking in the last year. The multiple logistic regression analysis revealed that two independent variables, exposure to second-hand smoke (SHS) both at home and in public places (OR = 3.26 and OR = 5.9, respectively), showed a significantly higher occurrence of smoking. There is a high use of tobacco among dental students, which is particularly high in Italian dental students. Students realizes the positive perception of their own tobacco counsellor role in a dental setting. Dental students should be role models to their peers and patients.

Evaluation of calcium and magnesium contents in tooth enamel without any pathological changes: in vitro preliminary study.

Enamel is the structure that covers the entire clinical crown of a tooth. It enables to chew and crush food, and gives a final shape to the crowns of teeth. To evaluate calcium and magnesium contents in tooth enamel and analyse relationships between the study minerals extracted human permanent teeth were cut at every 150 microns and subjected into acid biopsy. The amounts of calcium and magnesium were assessed in the laboratory using atomic absorption spectroscopy with an air/acetylene flame. The lowest calcium and magnesium contents were found on the enamel surface of the teeth. Statistically significant correlation between the calcium and magnesium concentrations was found at a depth between 150 and 900 µm. Calcium and magnesium contents increased with increasing enamel depth. Calcium and magnesium deposits appeared to be stable through all the enamel layers studied. It would be suggested that mineralization/demineralization affect only external layer of the enamel, whereas deeper layers are not affected by these processes.

The evaluation of zinc and copper content in tooth enamel without any pathological changes - an in vitro study.

OBJECTIVES: The objectives of the study were to evaluate the content of copper and zinc in individual layers of tooth enamel and to analyze the relationships between the study minerals in individual layers of tooth enamel. PATIENTS AND METHODS: Fifteen human permanent teeth were cut off every 150 µm alongside the labial surface. Acid biopsy of each layer was performed. The zinc content was determined using the air-acetylene flame method. The copper content was determined using the electrothermal technique with argon. RESULTS: The mean zinc concentrations increased significantly starting from the outer enamel surface, with the maximum concentration in the 150-300 µm layer. The mean copper concentrations increased substantially from the outer enamel surface to a depth of 150 µm, and then a slight downward trend of this mineral levels was seen, down to a depth of 450 µm. Strong positive correlation was found between the zinc and copper concentrations at depths of 150-300, 450-600 and 600-750 µm. CONCLUSION: The levels of zinc and copper in the outer enamel layers may have an effect on the increased content of unipolar minerals at deeper enamel layers. The content of the study elements determined may reflect the process of mineralization and maturation of enamel in the pre-eruption period.