In the 1st phase of this study, thirty patients were investigated. Five milliliter stimulated saliva was collected just before and after MRI. The magnetic flux density was 0.23 T and the duration of exposure of patients to magnetic field was 30 minutes. In the 2nd phase, fourteen female healthy University students who had not used mobile phones before the study and did not have any previous amalgam restorations were investigated. Dental amalgam restoration was performed for all 14 students. Their urine samples were collected before amalgam restoration and at days 1, 2, 3 and 4 after restoration. The mean +/- SD saliva Hg concentrations of the patients before and after MRI were 8.6 +/- 3.0 and 11.3 +/- 5.3 microg L(-1), respectively (p < 0.01). A statistical significant (p < 0.05) higher concentration was observed in the students used mobile phone. The mean +/- SE urinary Hg concentrations of the students who used mobile phones were 2.43 +/- 0.25, 2.71 +/- 0.27, 3.79 +/- 0.25, 4.8 +/- 0.27 and 4.5 +/- 0.32 microg L(-1) before the amalgam restoration and at days 1, 2, 3 and 4, respectively. Whereas the respective Hg concentrations in the controls, were 2.07 +/- 0.22, 2.34 +/- 0.30, 2.51 +/- 0.25, 2.66 +/- 0.24 and 2.76 +/- 0.32 microg L(-1). It appears that MRI and microwave radiation emitted from mobile phones significantly release mercury from dental amalgam restoration. Further research is needed to clarify whether other common sources of electromagnetic field exposure may cause alterations in dental amalgam and accelerate the release of mercury.

We evaluated the long-term speech intelligibility of young deaf children after cochlear implantation (CI). A prospective study on 47 consecutively implanted deaf children with up to 5 years cochlear implant use was performed. The study was conducted at a pediatric tertiary referral center for CI. All children in the study were deaf prelingually. They each receive implant before the program of auditory verbal therapy. A speech intelligibility rating scale evaluated the spontaneous speech of each child before and at frequent interval for 5 years after implantation. After cochlear implantation, the difference between the speech intelligibility, rating increased significantly each year for 3 years (P < 0.05). For the first year, the average rating remained "prerecognizable words" or "unintelligible speech". After 2 year of implantation the children had intelligible speech if someone concentrates and lip-reads (category 3). At the 4- and 5-year interval, 71.5 and 78% of children had intelligible speech to all listeners (category 5), respectively. So, 5 years after rehabilitation mode and median of speech intelligibility rating was five. Congenital and prelingually deaf children gradually develop intelligible speech that does not plateau 5 years after implantation.

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The protection motivation theory provides a useful framework for investigating factors of tobacco use among male students. Future tobacco prevention interventions should focus on increasing the vulnerability and fear, decreasing intrinsic reward, and improving self-efficacy to reduce tobacco use.

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