Direct measurement of ultrasonic activity on microbial metabolism and analysis of related uncertainty

The scope of this work is to identify the relation that exists between the alterations of the bacterial metabolism and the exposition to an ultrasonic field (O'Leary et al. 1997, Piyasena et al. 2003, Brujan2004). To made this relation quantifiable they will be used repeatable and reproducible metrological methods. To obtain this result the research will be centred on 3 specific goal: 1. To realise a measurement of the ultrasonic field, generated by an ultrasonic bath, using an hydrophone calibrated specifically with the wavelengths applied (Canney et al. 2008). 2. To choose a method, through uncertainty evaluation, to expose microbes to the ultrasonic field without an excessive alteration of the generated acoustic pressure. 3. To find a method to measure bacterial viability, represented by the planktonic growth and the biofilm development, after exposure to the ultrasounds. Studying the relationship between the bacteria metabolism and ultrasonic exposure it will be possible to identify novels and more precise methods to treat bacterial colonizations. This result will be in fact useful in various fields where the bacterial presence, and in particular biofilm development, is today an unresolved problem. At the same time this research will put the basis for many further studies that will be realized applying the same methods with different bacterial species, ultrasounds exposition conditions or ultrasonic devices

Direct measurement of ultrasonic activity on microbial metabolism and analysis of related uncertainty

The scope of this work is to identify the relation that exists between the alterations of the bacterial metabolism and the exposition to an ultrasonic field (O'Leary et al. 1997, Piyasena et al. 2003, Brujan2004). To made this relation quantifiable they will be used repeatable and reproducible metrological methods. To obtain this result the research will be centred on 3 specific goal: 1. To realise a measurement of the ultrasonic field, generated by an ultrasonic bath, using an hydrophone calibrated specifically with the wavelengths applied (Canney et al. 2008). 2. To choose a method, through uncertainty evaluation, to expose microbes to the ultrasonic field without an excessive alteration of the generated acoustic pressure. 3. To find a method to measure bacterial viability, represented by the planktonic growth and the biofilm development, after exposure to the ultrasounds. Studying the relationship between the bacteria metabolism and ultrasonic exposure it will be possible to identify novels and more precise methods to treat bacterial colonizations. This result will be in fact useful in various fields where the bacterial presence, and in particular biofilm development, is today an unresolved problem. At the same time this research will put the basis for many further studies that will be realized applying the same methods with different bacterial species, ultrasounds exposition conditions or ultrasonic device

Oil Essential Mouthwashes Antibacterial Activity against Aggregatibacter actinomycetemcomitans: A Comparison between Antibiofilm and Antiplanktonic Effects

The aim of this work is to determine the antibacterial activity of three marketed mouthwashes on suspended and sessile states of Aggregatibacter actinomycetemcomitans. The efficacy of two commonly used products in clinical practice, containing essential oils as active ingredients (menthol, thymol, methyl salicylate, and eucalyptol) in association with or without alcohol, has been evaluated in comparison with a chlorhexidine-based mouthwash. The microtiter plate assay, in order to obtain a spectrophotometric measurement of bacterial responses at growing dilutions of each antiseptic, was used for the study. The analysis revealed that a good antibacterial activity is reached when the abovementioned mouthwashes were used at concentration over a 1/24 dilution and after an exposure time of 30 seconds at least. In conclusion, the alcoholic mouthwash appears to have a better biofilm inhibition than its antiplanktonic activity while the nonalcoholic product demonstrates an opposite effect with a better antiplanktonic behavior

In Vitro Evaluation of Enterococcus faecalis Adhesion on Various Endodontic Medicaments

E. faecalis in endodontic infection represents a biofilm type of disease, which explains the bacteria’s resistance to various antimicrobial compounds and the subsequent failure after endodontic treatment. The purpose of this study was to compare antimicrobial activities and bacteria kinetic adhesion in vitro for three endodontic medicaments with a clinical isolate of E. faecalis. We devised a shake culture which contained the following intracanalar preparations: CPD, Endoidrox (EIX), PulpCanalSealer (PCS); these were immersed in a liquid culture medium inoculated with the microorganism. The shake system velocity was able to prevent non-specific bacteria adhesion and simulated the salivary flow. Specimens were collected daily (from both the medium and medicaments) for 10 days; the viable cells were counted by plate count, while the adhesion index AI° [E. faecalis fg DNA] /mm2 was evaluated in the pastes after DNA extraction, by quantitative real time PCR for the 16S rRNA gene. A partial growth inhibition, during the first 24 hours, was observed in the liquid medium and on the medicaments for EIX and subsequently for CPD (six logs). EIX showed the lowest adhesion coefficient (5*102 [fg DNA]/mm2) for nine days and was similar to the control. PCS showed no antimicrobial/antibiofilm properties. This showed that “calcium oxide” base compounds could be active against biofilm progression and at least in the short term (2-4 days) on E. faecalis cells growing in planktonic cultures

Probing depth in periodontal pockets: In vitro evaluation of contributions to variability due to probe type and operator skill

Periodontal probing aims at detecting the presence, type and gravity of periodontal diseases influencing distance between gingival margin and connective ligament. Measurements in vivo are affected by substantial uncertainty, owing, for example, to probe features, anatomic variations and operator’s skill. Inadequate reproducibility in periodontal probing may lead to diagnostic mistakes and inappropriate therapeutic decisions. In vitro evaluation of reproducibility of measurements of periodontal pockets was aimed at while developing a Periodontal Calibration Box designed to calibrate periodontal probe operators, catering also for simulating contraction observed in vivo. Probe type and clinical experience of operators were found to affect substantially probing errors

Microbial Changes in Subgingival Plaque and Polymicrobial Intracellular Flora in Buccal Cells after Fixed Orthodontic Appliance Therapy: A Preliminary Study

The oral ecosystem is strictly related to a balance maintained by specific niches recognized as sites, where oral bacteria can metabolize avoiding the immune system response. The oral bacteria species that colonize the ecological niches vary during fixed orthodontic treatment, with a prevalence of periodontal bacterial species. Qualitative analysis of five periodontal pathogens was used to investigate the microbial colonization rate in the crevice and buccal epithelial cells. The presence of inadequate oral hygiene was considered as a modulation variable for microbial colonization. Statistical analysis was performed by Fisher’s exact test, ANOVA, and Pearson correlation. A value lower than 0.05 was assumed as statistically significant. Tannerella forsythia was the only periodontal pathogen detected with a statistically admissible frequency. The positivity for Tannerella forsythia was correlated to sampling time and oral hygiene motivation. In buccal epithelial cells, both factors contributed to microbial decrease (), whereas, in crevice, oral hygiene motivation promoted a decrease in the microbial colonization rate (). According to microbiological findings, it is possible to identify how correct motivation for oral hygiene is more than enough to modulate or to avoid an upset of the oral ecosystem balance in early stages of orthodontic treatment

Ultrasonic transparency of sonication tubes exposed to various frequencies: A metrological evaluation of modifications and uncertainty of acoustic pressures

Correlations between biological phenomena and ultrasonic exposure often involve mechanical and thermal effects. Cavitation proved capable of interacting with other factors, making awkward the evaluation of their individual effects. In microbiological research, the presence of a dual effect of ultrasound on microorganisms, namely bactericidal and stimulating, required development of methods enabling analysis of ultrasonic field effects, shielded from those of cavitation. This work shows how acoustic wave action may be analyzed with a metrological approach, excluding cavitational effect and measuring acoustic pressure acting upon a sonication tube. Results show how such a goal was achieved in a repeatable and reproducible way, avoiding acoustic wave degeneration

Distribution of Human Papillomavirus Genotypes in Sardinian Patients with Oral Squamous Cell Carcinoma

Human papillomaviruses (HPVs) seem to play an important role in the pathogenesis of gynecological carcinomas and in head and neck carcinomas. The aim of this study was to detect and genotype HPVs in fresh oral squamous cell carcinoma (OSCC) from a Sardinian population, and to determine whether HPV presence was significantly associated with the development of OSCC.The oral mucosa tissues were obtained from 120 samples (68 OSCC and 52 control samples) taken from a Sardinian population seen at the Dental Clinic of the Department of Surgery and Odontostomatological Sciences, University of Cagliari (Italy) and the " Ospedale SS Trinità", Cagliari (A.S.L. 8) between 2007 and 2008. PCR was used for the detection of HPV DNA and the genotype was determined by DNA sequencing. The frequency of HPV infection was evaluated in relation to age, sex, smoking and alcohol use. Statistical analysis was performed using the SPSS 11.5 software.The results showed the presence of HPV-DNA in 60.3% of OSCC with HPV-16 (51.2%) being the most frequent genotype. In these Sardinian OSCC patients, HPV-DNA was detected more in males (65.8%) than in females (34.1%) while controls show a 0% of HPV presence. HPV positive was highly associated with OSCC among subjects with a history of heavy tobacco and alcohol use and among those with no such history.A greater frequency of high risk HPV presence was observed in patients with OSCC compared to health control patients. In addition these results suggested that oral HPV presence could be associated in OSCC subjects. Our results need more analyses to detect the HPV-DNA integration into tumoral cells