Gingivitis in Zurich schoolchildren. A reexamination after 20 years.

In 1957 the periodontal health of 1350 Zurich schoolchildren was assessed. The same investigator (M.Z.) examined 1217 children in the same school district 18 years later. 909 children were considered for statistical analysis. Only 9.1% were found to be free from gingival inflammation. 32% of the papillary and marginal gingival areas showed inflammatory signs. Prevalence of gingivitis was similar in different socioeconomic groups and in children treated by general practitioners and school dental clinics respectively. Gingivitis prevalence was remarkably similar in 1957 and 1975. An increase in the intensity of inflammation was, however, statistically significant. Reconsideration and modification of the existing measures in preventive periodontology are indicated.