“…Spirochetes have been reported in association with NUG by many authors (Hampp & Mergenhagen 1963, Listgarten & Socransky 1964, Listgarten 1965, Soames & Davies 1974, Listgarten 1976, Loesche et al 1982, Mikx & van Campen 1982. Penetration of spirochetes in the living tissues in NUG lesions has been reported since the beginning of the century (Ellerman 1907, Cahn 1929. More recently Schafl'er (1953), Listgarten and Socransky (1964), and Listgarten (1965) described spirochetes to penetrate the necrotized or necrotizing tissues at the diseased sites.…”