As indigenous oral bacteria, the Actinomyces are thought to contribute to caries especially to root caries. Therefore, it is great important to assess genic polymorphism of oral Actinomyces. Polymerase chain reaction（PCR） extensively utilized for research about oral bacteria recently. Here we review a series of PCR methods for assessing genic polymorphism of oral Actinomyces: random amplificaiton of polymorphic DNA（RAPD）, PCR restriction fragment length polymorphism（PCR- RFLP）and repetitive extragenic palindromic sequence- based polymerase chain reaction（REP- PCR）.
