Relationships between yeasts and primary root-caries lesions.

A total of 447 primary root-caries lesions from 169 dental patients was studied to determine the relationships between their clinical severity and the number and frequency of isolation of yeasts. Yeasts were isolated more frequently from soft lesions, from lesions at the gingival margin and from lesions deemed to require restoration. These associations may be due to the aciduricity and acido- genicity of yeasts but the relatively low numbers found do not support a pathogenic role for yeasts in the aetiology of root caries: at best they may be marker organisms of the most severe disease.