Results of more than 100 CPITN surveys from over 60 countries for the age group 15-19 years, stored in the WHO Global Oral Data Bank as of 1 August 1990, are assembled. They are presented in the form of graphs showing the mean number of sextants affected per person and arranged by country according to WHO regions. It is hoped that these overviews provide a frame of reference for the evaluation of periodontal conditions in populations and population subgroups. The most frequently observed condition in adolescents was score 2 (calculus with or without bleeding). Calculus seems to be much more prevalent in non-industrialized than in industrialized countries. Although some shallow pocketing of 4 or 5 mm was present in two-thirds of all populations observed, it affected mostly only a minority of the sample and then only in one or two sextants. However, a few surveys showed a relatively high prevalence of pocketing. As the surveys were carried out in adolescents, such high figures indicate serious problems ahead.