In 16 rural communities of the Canton of Zurich, school children of all age groups participated in dental examinations conducted at intervals of 4 years since 1963/64. The same standardised method was used throughout the entire period. This study documents the caries experience over a period of 45 years.
From 1964 to 2009, the DM*FT per 14-year-old child
fell from 12.50 to 1.31, corresponding to a caries
reduction of 90%. The caries experience in 8-, 10-
and 12-year-olds decreased by 90% to 92%.
From 1964 to 2009, the “Significant Caries Index”
(the mean DM*FT in the third of 12-year-olds with
the highest DM*FT values) fell from 13.09 to 2.20,
corresponding to a caries reduction of 83%.
The observed caries decline was unexpectedly high.
The effect of fluorides may explain a caries
reduction of roughly 50%. A large part of the
decline, however, remains unexplained. Possible
causes are discussed in this paper.