Intravital Uptake of Fluorides by the Teeth under Various Conditions

Abstract

One lower premolar is separated bilaterally from the oral cavity by aid of a rubber sac, fastened on the tooth by aid of a rubber dam clamp. The sac is filled with a NaF soln. In the soln. prior to application and after exposure of the tooth for various periods (5-20 min.) the F concn. is detd., and the F loss computed. The loss is regarded is being taken up by the intact tooth. Bilateral pairs of teeth show equal uptake under identical conditions. Prophylaxis prior to F application increases the uptake considerably. Increasing the amt. of concn. of the topically applied fluoride has no influence on the quantity of F taken up by the teeth, under the conditions of these experiments (100-200 [mu]g. F in 5-20 ml. fluid, exposure 5-20 min.). Longer exposure to the NaF soln. causes an increased uptake. From an acidulated NaF soln. (pH 4) more F is lost than from a neutral one; it is not clarified whether the F is taken up in this instance by the tooth or a precipitate of CaF2 with the dissolved Ca ions is formed. In persons below 18 yrs. the uptake is greater than in those over 20 yrs. Between MDF index and F uptake there is no demonstrable connection.