[Microbial colonization of carious progression stages in the dentin of human teeth--a controlled therapeutic study].

In a controlled clinical trial the microflora of the cavity floor of 70 primary lower second molars with deep carious lesions were determined after caries excavation. The teeth were extracted and pulpal status was evaluated after 16 months of microbial control to determine the etiopathogenic role of germs for carious progression in dentine. 67% of the primary molars were free from pulpal inflammations. Soft carious dentine were significantly higher infected than the clinically acceptable hard dentine. Only in 40% of the cavity floors the microorganisms were eliminated. In the infected teeth basophilic microorganisms were found in causality to pulps without inflammations; acidogenic streptococci and lactobacilli were involved in pulpal inflammations. Results indicate that the latter genera of microorganisms are of etiological significance for carious progression in dentine.