Pyrosequencing Analysis of Cryogenically Ground Samples from Primary and Secondary/Persistent Endodontic Infections

The present study revealed that the microbial diversity of secondary/persistent endodontic infections did not differ than those of primary endodontic infections. A new archaeal species, Candidatus Nitrosoarchaeum limnia, was detected in root canals of 1 patient with primary endodontic infection for the first time.