Table 1.

Classification of the characteristic clinical appearance of fluorotic incisor enamel in mice as modified from Thylstrup and Fejerskov [1978]

TF score 0	The normal translucency of the glossy creamy yellow enamel remains after wiping and drying of the tooth surface.
TF score 1	Thin white opaque lines are seen running across the tooth surface. Such lines are found on all parts of the surface. The lines correspond to the position of the perikymata.
TF score 2	The opaque white lines are more pronounced and frequently merge to form small cloudy areas scattered over the whole surface.
TF score 3	Merging of the white lines occurs, and cloudy areas of opacity spread over many parts of the surface. In between the cloudy areas, white lines can also be seen.
TF score 4	The entire surface exhibits a marked opacity or appears chalky white. Parts of the surface exposed to attrition or wear may appear to be less affected.
From Thylstrup and Fejerskov [1978] and Fejerskov et al. [1994].