Study of Defected Layers on Incisor Dentin in Magnesium-deficient Rats

Abstract

This study was performed to analyze the defected layers on incisor dentin in magnesium-deficient rats. Young (5 wk) Wistar male rats were pair-fed semi-synthetic diets containing either control [0.5% calcium (Ca), 0.05% magnesium (Mg) and 0.35% phosphorous (P)] (n=8) or Mg deficient [0.5% Ca, 0.001% Mg and 0.35% P] ingredients (n=8) for 17. For the dentin formation rate, all animals were given three intraperitoneal injections of a 0.1 mol nitrilotriacetato lead and 0.1 mol nitrilotriacetato zinc (2 mg/kg body weight as lead) combination at days 0, 7 and 14. In addition, blood samples were obtained from the tail on days 10 and 17 during the experimental period to measure Ca, Mg, P and ALPase activity levels in the serum, and rats were confirmed to become hypomagunesemic and hypercalcemic. After the 17th day, the rats were sacrificed under anesthesia and the right and left maxillary and mandibular incisors were removed. After the designated treatment, right maxillary incisors were used to measure the incisor dentin formation rate and left maxillary incisors were used to measure the length (diameter). The right mandibular incisors were used to measure the Ca, Mg and P content in the ash, and the left mandibular incisors were used to detect Ca, P and Mg concentrations on the dentin by X-ray line scans using a wavelength dispersive X-ray spectrometer (WDS : Microspec). The results showed decreases in body weight, incisor dentin formation rate, length of incisor and content of Mg in the ash incisors in Mg-deficient rats. Metal concentrations on the dentin as measured by WDS indicated an increase of Mg content in the abnormal layers. This phenomenon of increase in Mg content suggests condensing of Mg content as the results of a decrease in dentin formation rate during Mg deficiency, and temporary increase in Mg by transportation of Mg with the stagnation of growth cells and soft tissues.