Survival of microorganisms on complete dentures following ultrasonic cleaning combined with immersion in peroxide-based cleanser solution.

OBJECTIVES: To compare ultrasonic cleaning combined with immersion in a commercially available peroxide-based cleanser solution (Polident(®) ) with other denture cleaning methods, we examined the quantity of micro-organisms that survived on dentures before and after various cleaning methods. SUBJECTS AND METHODS: One hundred complete dentures belonging to 50 nursing home residents (mean age, 84.6 years) were randomly assigned to five groups according to the cleaning method employed: (A) immersion in Polident(®) solution alone, (B) brushing with water, (C) ultrasonic cleaning with water, (D) method (A) followed by method (B) and (E) ultrasonic cleaning combined with immersion in Polident(®) solution. Before and after the dentures had been cleaned, denture biofilm was collected from the mucosal surface of each lateral half of the examined dentures. The collected micro-organisms were cultured, presumptively identified by standard methods and quantified. Comparisons between the five cleaning methods were carried out using the Kruskal-Wallis test and Dunn's multiple comparisons test. RESULTS: The denture cleaning methods involving the use of Polident(®) solution (methods A, D and E) were significantly more effective at denture disinfection than the other methods (p < 0.05); in particular, the quantity of Candida spp. was lowest after method E (median, 0.00; significantly lower than those observed after methods A, B and C; p < 0.05). CONCLUSION: It was concluded that ultrasonic cleaning combined with immersion in a peroxide-based cleanser solution effectively reduces the quantity of micro-organisms surviving on dentures and is a suitable method for elderly individuals who find brushing their dentures difficult.

Characterization of oral bacterial diversity of irradiated patients by high-throughput sequencing.

The objective of this study was to investigate the compositional profiles and microbial shifts of oral microbiota during head-and-neck radiotherapy. Bioinformatic analysis based on 16S rRNA gene pyrosequencing was performed to assess the diversity and variation of oral microbiota of irradiated patients. Eight patients with head and neck cancers were involved in this study. For each patient, supragingival plaque samples were collected at seven time points before and during radiotherapy. A total of 147,232 qualified sequences were obtained through pyrosequencing and bioinformatic analysis, representing 3,460 species level operational taxonomic units (OTUs) and 140 genus level taxa. Temporal variations were observed across different time points and supported by cluster analysis based on weighted UniFrac metrics. Moreover, the low evenness of oral microbial communities in relative abundance was revealed by Lorenz curves. This study contributed to a better understanding of the detailed characterization of oral bacterial diversity of irradiated patients.

The effect of radiofrequency ablation on microbiology of the tonsils.

OBJECTIVE: To investigate the effect of tonsil size reduction using temperature controlled radiofrequency on the number of pathogenic bacteria in the tonsil tissue. MATERIALS AND METHODS: This study was performed on 25 patients who had undergone tonsillectomy under general anesthesia at our clinic. Immediately after the cold knife tonsillectomy both tonsils were removed, one was included in the control and the other one was included in the study group. In vitro radiofrequency was applied to the tonsil in the study group at eight distinct points, each lasting 15s. Biopsy materials were taken under sterile conditions from the center of each tonsil for further culturing. RESULTS: The difference in bacterial number was investigated between the two groups. The bacterial number following radiofrequency administration was found to be significantly very lower compared to the control group (p<0.01). Radiofrequency administration significantly reduced growth of all types of bacteria. CONCLUSION: The radiofrequency tonsil ablation technique, which is used safely and effectively in the management of obstructive tonsil hypertrophy, currently has no indication for the treatment of patients with chronic and recurrent tonsillitis. However, when the right conditions are provided, the radiofrequency tonsil ablation technique may be applied to patients with chronic and recurrent tonsillitis and further studies investigating the differences in the frequency of patients' tonsillitis episodes should be undertaken.

[Effects of low-intensity garnet laser irradiation on microorganisms and wounds]. / Vozdeistvie nizkointensivnogo granatovogo lazernogo izlucheniia na mikroorganizmy i rany.

The influence of low-intensity garnet laser radiation a wavelength of 0.53 microns (green spectrum) on Mycobacterium tuberculosis (MT), nonspecific microflora and regeneration of aseptic and purulent wounds has been studied experimentally for the first time. Irradiation of MT and nonspecific microflora inoculations has shown that this type of laser radiation fails to stimulate growth of MT and nonspecific microflora and has an inhibiting action on MT manifested by delayed MT growth, a lower number of dimensions of the growth colonies as compared to those of the control inoculations and has a bacteriostatic action on micrococci and Neisseria organisms. Influence of this type of laser on the aseptic and purulent wounds in 50 guinea pigs has revealed a more rapid regeneration of aseptic wounds (by 3-4 days) as compared to the control.

Aerosols of mycoplasmas, L forms, and bacteria: comparison of particle size, viability, and lethality of ultraviolet radiation.

Aerosols of microorganisms were tested for particle size by use of an Andersen sampler. Mycoplasma aerosols had an average count median diameter (CMD) of 2.1 +/- 0.5 mu. Staphylococcus aureus L forms gave an average CMD of 4.6 +/- 1.7 mu; the diphtheroid L form, a CMD of 3.4 +/- 0.3 mu. Escherichia coli had a CMD of 5.4 +/- 2.5 mu; Neisseria sicca, 3.3 +/- 0.5 mu; N. meningitidis, 3.4 +/- 0.2 mu. S. aureus ATCC 6538, the parent strain of the L form, yielded a CMD of 3.9 +/- 1.2 mu. Candida albicans gave an average CMD of 5.9 +/- 1.4 mu. All organisms tested survived aerosolizing and could be recovered in viable form for at least 1 hr. Ultraviolet radiation at 2,537 A destroyed the bacteria and mycoplasmas instantaneously, and destroyed 87% of the L forms of S. aureus, 69% of the diphtheroid L form, and 98% of the C. albicans cells. After irradiation, viable particles of the L form and C. albicans aerosols were consistently larger, indicating that clumping led to survival. Submicron size particles were found in aerosols of all species tested except C. albicans.