Air-polishing followed by ultrasonic calculus removal for the treatment of gingivitis: A 12-month, split-mouth randomized controlled clinical trial.

OBJECTIVE: To evaluate the advantages of a novel protocol involving full-mouth erythritol-powder air-polishing followed by ultrasonic calculus removal in the maintenance of patients treated for gingivitis, with a focus on time and comfort. METHODS: Systemically healthy patients with gingivitis were selected. Following a split-mouth design, quadrants 1-4 and 2-3 were randomly allocated to receive air-polishing followed by ultrasonic calculus removal following a protocol known as Guided Biofilm Therapy (GBT) or traditional full-mouth ultrasonic debridement followed by polishing with a rubber cup and prophylactic paste (US + P). Bleeding on probing (BoP) and the plaque index (PI) were collected at baseline (T0), 2 weeks (T1), 4 weeks (T2), 3 months (T3), and 6 months (T4) and 12 months (T5). Following the same randomization, prophylactic therapy was provided at 3 months (T3) and 6 months (T4). Clinical parameters, treatment time and patient comfort and satisfaction were evaluated. RESULTS: A total of 41 patients were selected, 39 completed the study. The clinical parameters were clinically satisfactory for both treatments at every time. At 4 months after treatment, GBT maintained significantly lower BoP and PI. GBT protocol required a significantly lower treatment time, especially at T3 and T4, when it saved 24.5% and 25.1% of the time, respectively. Both treatments were rated positively by most patients. However, GBT was perceived as more comfortable, and a higher number of patients preferred it. CONCLUSION: No significant difference was observed between GBT and conventional ultrasonic debridement and rubber cup polishing in terms of BoP and PI levels. The GBT protocol allowed less time expenditure and higher patients' perceived comfort.

Single molecule fluorescence resonance energy transfer scanning near-field optical microscopy: potentials and challenges.

A few years ago, single molecule Fluorescence Resonance Energy Transfer Scanning Near-Field Optical Microscope (FRET SNOM) images were demonstrated using CdSe semiconductor nanocrystal-dye molecules as donor-acceptor pairs. Corresponding experiments reveal the necessity to exploit much more photostable fluorescent centers for such an imaging technique to become a practically used tool. Here we report the results of our experiments attempting to use nitrogen vacancy (NV) color centers in nanodiamond (ND) crystals, which are claimed to be extremely photostable, for FRET SNOM. All attempts were unsuccessful, and as a plausible explanation we propose the absence (instability) of NV centers lying close enough to the ND border. We also report improvements in SNOM construction that are necessary for single molecule FRET SNOM imaging. In particular, we present the first topographical images of single strand DNA molecules obtained with fiber-based SNOM. The prospects of using rare earth ions in crystals, which are known to be extremely photostable, for single molecule FRET SNOM at room temperature and quantum informatics at liquid helium temperatures, where FRET is a coherent process, are also discussed.

Maxillary fungus ball: zinc-oxide endodontic materials as a risk factor.

The objective of this study was to demonstrate the correlation between endodontic treatment on maxillary teeth and fungus ball with inductively coupled plasma mass spectrometry measurement of zinc and other metals (barium, lead and copper) in fungus ball samples. Samples of normal maxillary mucosa were used as comparison. Metal concentration was also measured in several endodontic materials. A significant difference was found between the concentration of zinc and copper in fungus ball compared to normal mucosa. Metal distribution was more similar in fungus ball and in the endodontic materials tested than normal mucosa. The similar metal concentration in the endodontic materials and fungus ball suggests that endodontic materials play a role in the pathogenesis of fungus ball. Endodontic materials accidentally pushed into the maxillary sinus during endodontic treatments may play a crucial role. Dentists should be as careful as possible when treating maxillary teeth to avoid perforating the maxillary sinus floor; the use of zinc-free endodontic materials, as zinc is a metal that plays a pivotal role in fungus growth, should be encouraged.

Near-field scanning optical microscopy using polymethylmethacrylate optical fiber probes.

We report the first use of polymethylmethacrylate (PMMA) optical fiber-made probes for scanning near-field optical microscopy (SNOM). The sharp tips were prepared by chemical etching of the fibers in ethyl acetate, and the probes were prepared by proper gluing of sharpened fibers onto the tuning fork in the conditions of the double resonance (working frequency of a tuning fork coincides with the resonance frequency of dithering of the free-standing part of the fiber) reported earlier for the case of glass fibers. Quality factors of the probes in the range 2000-6000 were obtained, which enables the realization of an excellent topographical resolution including state-of-art imaging of single DNA molecules. Near-field optical performance of the microscope is illustrated by the Photon Scanning Tunneling Microscope images of fluorescent beads with a diameter of 100nm. The preparation of these plastic fiber probes proved to be easy, needs no hazardous material and/or procedures, and typical lifetime of a probe essentially exceeds that characteristic for the glass fiber probe.

[In vitro study of amalgam corrosion]. / Studio in vitro sulla corrosione di amalgami.

AIMS: In the dental field, the aim of the research was to evaluate, through a standardized system, the factors influencing the corrosion of dental alloys in different clinical conditions with various types of amalgams and/or solution parameters. METHODS: A 6-hole corrosion cell was used according to ASTM G5-95 protocol. RESULTS AND CONCLUSIONS: It is well known that free surface corrosion is uncommon in the oral cavity in the case of most dental alloys. But localized corrosion, either as pitting or as crevice corrosion, might occur. The clinical conditions affecting amalgam corrosion may be detectable in localized corrosion, in particular because of cathodic/anodic surface behaviour coupling.

[Carcinoma of the urethra in patients having undergone cystectomy for neoplasm of the bladder]. / Il carcinoma dell'uretra nei pazienti cistectomizzati per neoplasia vescicale.

The multifocality of the cancer of the urethra is a concept already known so for time, therefore urethral lesions are expected in patients with carcinoma of the bladder with an incidence which varies from 4% to 18%. A retrospective study of incidence of transitional cell carcinoma of the urethra of personal sample of patients having cystectomy is reported. Of 259 patients who underwent cystectomy 13 developed a urethral tumour; 7.7% according to the international literature. The paper regards the characteristics of the urethral tumour by defining patients liable to risk where the carcinoma is plurifocal, or situated at the neck of the bladder and where frequent endoscopic operations have been performed or when there is a urethral "ca in situ". In these cases cystourethrectomy is suggested while the urethra is removed in presence of positive cytology in other forms. According to the authors' experience the survival of patients who have undergone a urethrectomy after cystectomy is 46%.