The relationship between the occurrence of caries and diabetes was explored in 80 children and adolescents with insulin-dependent diabetes mellitus. The mean age of the subjects was 14.5 years (range 11.7-18.4 years) and duration of diabetes 0.3-15.0 years (mean 6.0 years). DFS indices in poorly controlled subjects (glycosylated haemoglobin, HbA1, values over 13%) were significantly higher than in moderately (HbA1 10.0-12.9%) or in well-controlled cases (HbA1 values