Evaluation of the substantivity of chlorhexidine in association with sodium fluoride in vitro Avaliação da substantividade da clorexidina na associação com fluoreto de sódio in vi tro

AB STRACT: The ef fi cacy of the flu o ride-chlorhexidine as so ci a tion in the pre ven tion of gin gi vi tis and car ies has been ad vo cated for a num ber of years5,7,14. The ob jec tive of the as so ci a tion of these ther a peu tic agents is a syn er gis tic ac tion. The aim of the pres ent study was to de ter mine the substantivity of chlorhexidine as so ci ated or not to so dium flu o ride at dif fer ent in ter vals of time, in vi tro. Bo vine enamel sur faces were treated with 0.12% chlorhexidine gluconate (Periogard® – Colgate®) or 0.05% so dium flu o ride with 0.12% chlorhexidine (Duplak® – Dentsply®) so lu tions for one min ute. Frag ments were placed in dis tilled wa ter and sam ples were col lected at in ter vals of 5, 30 and 360 min utes and an a lyzed by spectrophotometry in the vis i ble ul tra vi o let re gion. Substantivity was eval u ated by the mea sure ment of chlorhexidine desorption from the treated slabs. The mean val ues ob tained were sta tis ti cally an a lyzed by Stu dent’s t-test. The re sults showed that the con cen tra tion of chlorhexidine de creased when it was used in as so ci a tion with so dium flu o ride. The dif fer ence be tween the groups was sta tis ti cally sig nif i cant (p < 0.05). These in vi tro re sults sug gest that the as so ci a tion be tween so dium flu o ride and chlorhexidine in the stud ied con cen tra tions ap pears to have no ben e fi cial ef fect be cause of the de crease in the substantivity of chlorhexidine. DESCRIPTORS: Chlor he xi di ne; So di um flu o ri de; Subs tan ti vity.