Sixty two patients (mean age 45.6 years) were assessed for oral hygiene and periodontal disease by dental examination before endoscopy. Information about oral care, smoking, and dentures was obtained and samples of dental plaque collected. The presence of Helicobacter pylori in plaque as sought by culture and polymerase chain reaction (PCR), and gastric antral biopsy specimens were taken for histological examination. Although H pylori was detected in the antral specimens of 34 patients (540/o) all of the cultures of dental plaque were negative, and PCR was only positive from the dentures of one patient. Smokers had poor oral hygiene, visited their dentist less often, and brushed their teeth less frequently. There was no correlation of H pyloni gastritis with either dental hygiene or periodontal disease. These results suggest that dental plaque or dentures are not an important reservoir for H pylon and are probably not a significant factor in transmission of the organism. The conflicting results in published works may be caused by differences in sample collection, culture techniques, or oral contamination from gastric juice as a result of gastro-oesophageal reflux at the time of endoscopy. (Gut 1995; 37: 44-46)

Graphical abstract

A numerical procedure is applied for the solution of the non-linear problem of propagation of waves generated in a homogeneous fluid, occupying an infinite channel, by the bounded motion of the bottom. For the sake of comparison, the analytical solution of the corresponding linearized problem is also given. The obtained results show that for sufficiently small amplitude of the bottom's motion, the predictions of the linear theory are in good agreement with those of the nonlinear theory only in some starting time interval, this interval being longer for smaller amplitudes. In the course of time, a growing oscillatory divergence is found to exist between the two theories. This divergence increases significantly with the increase of the amplitude of the bottom's motion. Numerical results are presented and discussed. Unlike results of other publications, the numerical scheme given here proves numerical stability for the considered cases.

No abstract

BACKGROUND: The effectiveness of the application of topical fluorides in prevention of erosive tooth wear has been an issue of controversy in the literature. The objective of this systematic review was to assess in situ studies investigating the effects of using topical fluorides on prevention of erosive tooth wear MATERIAL AND METHODS: Two electronic databases PubMed/MEDLINE and Cochrane Central Register of Controlled Trials were searched. Eligibility criteria included in situ-controlled studies that assessed the effect of the erosive process without additional tooth brushing. The search involved English-written articles only. A total of 684 potentially relevant titles and abstracts were found after removal of duplicates, of which 22 full-text articles were selected. Seventeen studies were included in the qualitative synthesis of which 6 studies included in the meta-analysis. The following data were obtained for each study: authors, year of publication, country, study design, periods of study, duration, blinding, interventions (type/concentration/form), tooth substrate, location of the intraoral appliance, number of samples attached to each appliance, type of acidic media used for erosive challenge, duration of erosive challenge, subjects (number/age/sex), reported side effects -if any-, measuring device, amounts of tissue loss. RESULTS: The risk of bias of the included studies was assessed using the Cochrane Collaboration tool for assessing the risk of bias. A meta-analysis of the present study was performed using Comprehensive Meta-Analysis version 2.2.048 software. CONCLUSION: The use of oral hygiene products containing AmF/NaF/SnCl2 or NaF may be effective in the prevention of erosive tooth wear.