DENTIN PERMEABILITY TO BACTERIAL PROTEINS IN-VITRO

Passage of bacterial components through dentin is a subject of recent research with in vitro as well as with in vivo models. Diffusive trans port of Porphyromonas gingivalis ATCC 33277 proteins has been demonstr ated by the authors with an in vitro setup closely simulating the pulp chamber. The purpose of this investigation was to study the filtratio n of these proteins through dentin, measure possible concentration cha nges resulting from the filtering, and elaborate on the physical aspec ts of the binding process. The hydraulic conductance (Lp) of 10 dentin specimens was determined in three experiments using standard procedur es: initially with phosphate-buffered saline, subsequently with a P. g ingivalis ATCC 33277 suspension (200 mug/ml of protein), and finally w ith phosphate-buffered saline. The results showed significant, nonperm anent, alterations of the Lp(s) of the dentin disks, and variable rete ntion of the bacterial proteins among samples. A positive correlation between the bacterial protein retention and reduction of Lp(s) was als o demonstrated. The reduction of the Lp(s) of the dentin samples was a ttributed to microstructural changes of the dentin, while the bacteria l protein retention was considered to take place either on the surface of the disk or intratubularly. The intratubular interactions in the p resent experiment seemed to have a mechanical rather than a chemical b asis.