[Arturo Beretta and the "trophomicrobic theory of the caries"]

The most original contribution made by the Italian School to the study of caries aetiology is undoubtedly the "trophomicrobic theory" proposed by Arturo Beretta, the first teacher of dentistry at the University of Bologna in 1918. This article brings biographical and bibliographical notes about Beretta (who was, among other things, Dean of the Faculty of Medicine of Bologna and Senator), and summarises the principles of his theory, which adds to Miller's "chemical-parasitic" theory of caries-predisposing properties of the enamel and host saliva. It also recalls the work of major Italian and non-Italian researchers who have used or modified Beretta's idea.