The Penetration of Porphyromonas gingivalis LPS into the Periodontally Involved Cementum

Abstract

The purpose of this study is to identify the extent of penetration of Porphyromonas gingivalis (P. g.) LPS into the periodontally involved cementum.
LPS of P. g. # 381 was extracted by using Phenol -Water method by Westphal et al . LPS was purified, and, mixted with Freund's complete adjuvant. This emersion was injected into rabbits and anti -LPS rabbit IgG was purified .
Periodontally involved teeth and periodontally healthy teeth (as negative control) were examined by immunohistochemical tecniques. These teeth were separated into two groups.
In the first group, proceeding extraction, test teeth were fixed, and divided into small blocks. These blocks were dehydrated, and embedded in resin, and 1 μ sections were prepared. Specimens were incubated with anti-LPS rabbit IgG or normal rabbit serum (as reagent control) and Fluorescein isothiocyanate (FITC) conjugated anti-rabbit goat IgG. Obsevations of P. g. LPS penetration were made by Fluorescence microscopy.
In the second group, the teeth were incubated with anti-LPS rabbit IgG immediately after fixation, and test teeth were incubated with biotinylated anti -rabbit goat IgG by Streptavidin biotin system . 400 μ horizontal sections were made and P. g. LPS penetration were observed by means of light microscopy. Furtheremore, another group of teeth undergoing same procedure without horizontal sectioning were ultrasonicated for 1, 5, 10, 30, 60 minutes and LPS elution were observed. As a result, in most teeth, LPS was detected only on surfaces of the exposed cementum with exception of 1 tooth in which LPS was detected in exposed cementum, but not in dentin. Furthermore, LPS was eluted by only 5 minutes ultrasonication.