The aim of the study was to examine the relationship between oral hygiene level and caries experience in 14-year-olds using fluoride dentifrices on a regular basis. Oral hygiene expressed as Gingival Bleeding Points (GBP) was recorded in 267 individuals in the county of Lillehammer in Norway. Total caries experience as DMFS and approximal carious lesions in the outer half of the enamel (D1), in the inner half of the enamel (D2), in dentin (D3), and filled approximal surfaces were registered clinically and on standardized bite-wing radiographs. Using multiple regression analysis, oral hygiene level expressed as GBI was the only factor that could account for variation in caries experience (DMFS). Any significant effect of consumption of sweets on caries experience could not be demonstrated with the multivariate analysis. The average percentage of GBP (+/- SD) was 35.7 +/- 10.0%. The individuals were divided into one group with good oral hygiene (GBP or = 35.7%). Significantly fewer carious lesions and filled approximal surfaces were demonstrated in the group with good oral hygiene compared with the group with poor oral hygiene. About 16% of the study population used fluoride tablets or fluoride mouthrinses in addition to a fluoride toothpaste. Only in the good oral hygiene group, additional fluoride resulted in a lower caries experience compared with those using only a fluoride toothpaste. In the group with poor oral hygiene, additional fluoride did not result in lower caries experience. The study thus supported the view that during regular fluoride exposure oral hygiene level is an important variable to explain caries risk.