Evaluation of dentin permeability of fluorotic permanent teeth.

OBJECTIVE: The in vitro permeability characteristics of dentin have been studied extensively and used to evaluate the efficacy of various preventative and restorative procedures. The aim of this in vitro study was to precisely determine the dentin permeability of fluorotic premolar teeth using an electronic hydraulic conductance measurement system with photosensors and to compare the data with healthy premolars. METHODS: In total, 40 fluorotic and healthy premolar teeth with complete root formation that were extracted for orthodontic purposes and had no caries, restoration, fractures, or cracks were selected for this study. Teeth were classified according to a modified form of the dental fluorosis index of Thylstrup and Fejerskov. The dentin discs were placed in an electronic hydraulic conductance measurement system equipped with photosensors, which was designed for measurements of dentin permeability. The amount of distilled water passed through each dentin disc (µL/min) under a constant pressure was determined. Dentin permeability data of the fluorotic and healthy teeth were recorded and analyzed statistically. RESULTS: The present study showed that fluorosis influenced the volume of fluid that passed through the dentin and the dentin permeability was decreased, whereas dental fluorosis severity was increased in permanent teeth. CONCLUSION: The number of teeth with fluorosis is increasing, depending on fluorine sources, so more appropriate treatments will need to be evaluated by standardizing the methods employed in related studies.

Effects of 50 Hertz-1 mT magnetic field on action potential in isolated rat sciatic nerve.

The aim of this study was to investigate possible effects of 50 Hz-1 mT magnetic field (MF) on action potential in isolated rat sciatic nerve. We used 16 Wistar rats in the study. They were divided into control (n = 10) and MF (n = 6) groups. The sciatic nerve of left legs in the MF group was exposed to 50 Hz-1 mT MF for 30 min by using a Helmholtz applicator and then action potentials in control and experimental groups were recorded extracellularly. Maximum amplitude and hyperpolarization time and action potential were significantly (p ≤ 0.025) lower in the MF group than in control. However, conduction time, minimum amplitude, depolarization and repolarization times of the action potential was not different between control and MF groups evaluated. In conclusion, 50-1 mT MF caused to decrease amplitude value and hyperpolarization time of action potential in the rat nerve.