Early plaque growth and plaque topography were studied in 15 young adults with a healthy periodontium during a 4-day period of no oral hygiene. After perfect tooth-cleaning, the recolonisation of the buccal surfaces of 48 teeth (front teeth and premolars) was recorded at the start and after 6, 12, 24, 30, 36, 48, 54, 60, 72, 84 and 96 h. At each visit, reproducible colour slides of the buccal tooth surfaces were taken after plaque disclosure. Plaque extension was calculated planimetrically as a % of the total surface area of the tooth. At the end of the experimental period, an average of 27.7% of the surface area was covered by plaque. The early plaque growth followed an exponential curve with a slight tendency for saturation at 96 h. During the night, the plaque growth rate decreased by up to 50%. Clear differences in plaque growth rate were observed between types of teeth, and the plaque growth pattern seemed to be closely correlated to irregularities of the tooth surface. The discontinuity in plaque growth and the influence from the tooth surface roughness have important implications for oral hygiene planning.