MACROMOLECULAR LEAKAGE BENEATH FULL CAST CROWNS .1. THE DIFFUSION OF LIPOPOLYSACCHARIDE AND DEXTRAN

Fifteen extracted molars were prepared for crowns. Crowns with access ports (one facial, one lingual) were cast in gold. Teeth and crowns wi th filters inserted into the ports were immersed in solutions of diffe rent concentrations of labeled and unlabeled macromolecules (fluoresce in isothiocyanate-dextran, tetramethylrhodamine isothiocyanate lipopol ysaccharide [LPS], unlabeled LPS) and were evaluated for leakage, Retr ieved filters were analyzed with fluorescent microscopy. At 10 mu g/ml , only LPS leaked beneath the crowns in 24 hours (p = 0.0002), but aft er a 1-week immersion, both LPS and dextran leaked beneath the crowns. LPS scores were higher (p = 0.0002) than dextran scores. Slightly mor e LPS leakage occurred at 1 week than at 24 hours. LPS appeared to inh ibit dextran diffusion beneath the cast crowns. Neither LPS nor dextra n influenced LPS diffusion. Factors other than molecular size and weig ht may play a more important role in the microleakage occurring beneat h crowns.