Effect of Fluoridated Water on Plasma Insulin Levels and Glucose Homeostasis in Rats with Renal Deficiency

Glucose intolerance in fluorosis areas and when fluoride is administered for the treatment of osteoporosis has been reported. Controlled fluoridation of drinking water is regarded as a safe and effective measure to control dental caries. However, the effect on glucose homeostasis was not studied so far. The aim of this study was to evaluate the effect of the intake of fluoridated water supply on glucose metabolism in rats with normal and deficient renal function. Male Sprague-Dawley rats were divided into eight groups of four rats. Renal insufficiency was induced in four groups (NX) which received drinking water containing 0, 1, 5, and 15 ppm F (NaF) for 60 days. Four groups with simulated surgery acted as controls. There were no differences in plasma glucose concentration after a glucose tolerance test between controls and NX rats and among rats with different intakes of fluoride. However, plasma insulin level increased as a function of fluoride concentration in drinking water, both in controls and in NX rats. It is concluded that the consumption of fluoridated water from water supply did not affect plasma glucose levels even in cases of animals with renal disease. However, a resistance to insulin action was demonstrated.

Ultrastructural Analysis of Radicular Dentine Surface Submitted to CO(2) Laser at Different Parameters

Background: There are no reported studies comparing different parameter settings of the CO(2) laser and irradiation direction considering their effect on the morphology of radicular dentine surface. Purpose: To evaluate the alterations of radicular dentine (cervical, middle, and apical thirds) irradiated with CO(2) laser at different potencies and irradiation directions. Study Design: Roots of 35 canines were prepared and randomly distributed according to the laser potency: GI: no laser treatment (control) (n = 5); GII, 2 W (n = 10); GIII: 4 W (n = 10); GIV: 6 W (n = 10). Each group (excepting GI) was divided in two subgroups according to the irradiation distance (n = 5): (A) parallel and (B) perpendicular to the root canal walls. The roots were splited longitudinally and analyzed by scanning electron microscopy in a qualiquatitative way. The scores were submitted to Kruskal-Wallis and Dunn`s tests. Results: No significant statistical differences were observed among root canal thirds (P > 0.05). The specimens irradiated with 2 W were statistically different (P < 0.05) from those irradiated with 4 and 6 W, which were statistically similar between themselves (P > 0.05). With 2, 4, and 6 W at in parallel irradiation and 2 W in perpendicular direction, the surface showed a fissured aspect. With 4 W in perpendicular direction and 6 W in parallel and perpendicular direction, surface was modified by laser action and exhibited fused areas. Conclusions: The intensity of the effects is dependent on the laser-irradiation dosimetries. Alterations were more intense when higher parameters were used. Microsc. Res. Tech. 72:737-743, 2009. (C) 2009 Wiley-Liss, Inc.