The<unk>  are first reported in 1947 and 1965. In a Swedish population it was first reported 1994. Among 1150 consecutively examined patients aged 20 –75 years, 10 showed<unk> . Among 2000 biopsy cases from 1989 - 1992 in Department of Oral Pathology Lund University, 15 biopsies met the criteria of<unk> .
Retrocuspid papilla
Soemmering ring
Pili bifurcati
Kronig isthmus
Vossius ring
Dennie–Morgan fold
Stenopaeic slit
Pili multigemini