Int. J. Environ. Res. Public Health 2009, 6 2505 Figure 3. Criteria of the Universal Visual Scoring System for smooth surfaces (UniViSS smooth). For analyzing the caries activity lesion-related factors, e.g., discoloration, location on the tooth surface, presence or absence of plaque and superficial texture/roughness play an important role in addition to patient-related factors such as age, individual caries risk, oral hygiene, tooth-friendly nutrition and fluoride intake. White and white-brown colored lesions, plaque coverage, roughness and the location in plaque retentive areas are strong indicators of a lesion which is active (Table 2). Table 2. Clinical indicators of inactive and active caries lesions on occlusal and smooth surfaces. Occlusal pits and fissures Smooth surfaces Inactive Persistence of the lesions over years/decades No plaque coverage Glossy, shiny appearance of the enamel surface after air- drying No pathological enlargements Active Detection within some years after tooth eruption Plaque coverage Matt/frosty/rough appearance of the enamel surface after air-drying Microcavities Inactive Persistence of the lesions over years/decades No plaque coverage Glossy, shiny appearance of the enamel surface after air- drying Lesions located in distance to the gingiva Active Detection within some years after tooth eruption Plaque coverage Matt/frosty/rough appearance of the enamel surface after air-drying White spots near the gingiva margin Brown discoloration in enamel White(-brown) discoloration in enamel Brown discoloration in enamel White(-brown) discoloration in enamel Hard, dry, discolored dentine Soft, wet, (un)discolored dentine Hard, dry, discolored dentine Soft, wet, (un)discolored dentine