BackgroundThis study identified optimistic biases in health and oral health hazards, and explored whether comparative risk judgements for oral health hazards vary systematically with socio-economic characteristics and self-reported risk experience.MethodsA simple random sample of 1,190 residents born in 1972 was drawn from the population resident in three counties of Norway. A total of 735 adults (51% women) completed postal questionnaires at home.ResultsMean ratings of comparative risk judgements differed significantly (p < 0.001) from the mid point of the scales. T-values ranged from -13.1 and -12.1 for the perceived risk of being divorced and loosing all teeth to -8.2 and -7.8 (p < 0.001) for having gum disease and toothdecay. Multivariate analyses using General Linear Models, GLM, revealed gender differences in comparative risk judgements for gum disease, whereas social position varied systematically with risk judgements for tooth decay, gum disease and air pollution. The odds ratios for being comparatively optimistic with respect to having gum disease were 2.9, 1.9, 1.8 and 1.5 if being satisfied with dentition, having a favourable view of health situation, and having high and low involvement with health enhancing and health detrimental behaviour, respectively.ConclusionOptimism in comparative judgements for health and oral health hazards was evident in young Norwegian adults. When judging their comparative susceptibility for oral health hazards, they consider personal health situation and risk behaviour experience.