A questionnaire was given to representative samples of Norwegian recruits in 1990 and 1999 to explore dental health habits, history of gastroesophageal disorders and diet with possible relations to dental erosion. The samples were 792 (mean age 20.9 years) and 676 (mean age 21.6 years), respectively, and the corresponding responses were 62% and 100%. Minor differences in self-reported dental health habits and gastroesophageal disorders were found. The respondents' dentists had provided information about dental erosion for 8.2% of the respondents in 1990 versus 14.5% in 1999. There was an increase in the reported frequency of daily intake of juice from 17% to 24% (P = 0.006) and carbonated soft drink from 54% to 61% (P = 0.025) in the period 1990-99. The frequency of training activity showed minor changes, but in 1999 it was more common to drink during exercise (94% versus 74% in 1990, P