[Reproducibility of plaque formation in the dento-gingival region (3)].

Plaque formation in the lower front teeth was recorded in 12 volunteers during three periods of twelve daily visits. Special interest was paid to finding which areas always contained deposits and which were always completely free of plaques. The causative aspects of regular plaque formation were demonstrated. The predominant role of surface roughness is discussed. As a clinical consequence, testing the enamel surface with the sound is suggested for the prophylaxis of gingivitis and caries.