[rgpB genetic polymorphism of Porphyromonas gingivalis in subgingival plaque].

OBJECTIVE

To analyse the genetic polymorphism of Arg-gingipainB (rgpB), a virulent factors of Porphyromonas gingivalis (P.gingivalis) and discuss the role of the different genotypes in the genesis and progress of chronic periodontitis.

METHODS

A total of 104 subgingival plaque samples were included in this study. The extracted DNA was amplified with the primers designed to obtain the gene encoding the catalytic domain of rgpB (rgpB-cd), P.gingivalis was typed into four genotypes by restriction fragment length polymorphism (RFLP).

RESULTS

In lesion site, the detection rate of type IV was the highest (52.78%), which was higher than those of type I and III (P < 0.05 or P < 0.01). While in non-lesion site, The detection rate of type II was the highest (75.86%), which was higher than those of other types (P < 0.01).

CONCLUSIONS

The polymorphism of rgpB-cd gene may influence the virulence of P.gingivalis. P.gingivalis type IV may be well related to periodontitis, while type II may be a indigenous flora.