Relationship between oral hygiene and approximal caries in 15-year-old Norwegians

The objective of the present study was to investigate the relationship between oral hygiene level, as judged from the number of non-bleeding papillae (NBP), and approximal caries development and progression in 14- to 15-year-old Norwegians. NBP, according to Gjermo, were registered in 165 15-year-old Norwegians. Approximal lesions in the outer half (D1) or in the inner half (D2) of the enamel or in dentin (D3) and the total numbers of carious approximal surfaces (D1 + D2 + D3), filled approximal surfaces, and sound approximal surfaces were recorded from bite-wing radiographs from premolars and molars at the age of 14 and 15 years (values expressed as mean +/- SD). The average number of NBP in the whole group was 4.6 +/- 4.5. One group with good oral hygiene (NBP > or = 5, 8.7 +/- 3.3, n = 76) and one group with bad oral hygiene (NBP < 5, 1.2 +/- 1.5, n = 89) were established. Carious approximal surfaces and filled approximal surfaces were significantly higher in the group with few than in the group with many NBP (6.0 +/- 5.9 vs. 1.7 +/- 2.8 and 2.6 +/- 4.3 vs. 0.9 +/- 1.8, respectively). The number of lesions at the age of 15 and progression of lesions from 14 to 15 years were also significantly higher in the group with few NBP. It is concluded than in populations exposed regularly to fluoride, the oral hygiene level may be an important indicator of a high caries risk.