Early Natural Subsurface Caries

The surface of natural proximal subsurface caries lesions was studied in a scanning electron microscope (SEM) before and after treatment and remineralization in an in vivo model. The material consisted of proximal subsurface lesions from 9 premolars. In 7 cases, one half of each lesion was studied directly and the other half remineralized in vivo before observation in the SEM. In 2 cases the same surface was studied before and after remineralization. The clinical treatment included effective oral hygiene, daily rinsing with 0.05% NaF solution, use of 0.1 % NaF toothpaste and application of Duraphat® varnish every 10th day for 8–10 weeks. The clinical result showed smooth and lustrous surfaces after 8–10 weeks. In the SEM the remineralized surfaces had a more regular and homogeneous appearance with more densely packed and larger crystallites compared to the untreated caries lesions. There was no difference regarding surface characteristics between parts where the lesions were still clinically visible and parts that were clinically healed. This indicates that clinical healing, in the sense that the area of the lesion is no longer clinically visible, does not depend solely on changes in the surface, but also on changes in deeper parts of the carious enamel.