Abstract
To examine the three dimensional morphology of tag-like extensions which are believed to be significant in the formation of bonds between resin sealant and etched human enamel, the present study was made using light microscopy and scanning electron microscopy.
The tag-like extensions formed in many etched labial and occulusal enamel surfaces of permanent teeth showed a honeycomb-like structure due to enamel prisms when observed by SEM and the tag length observed by light microscopy was 2 to 5 times longer than that by SEM. The results suggested that even if sealant was lost from etched enamel surfaces by fracture or/and abrasion, the enamel surfaces retain the part of sealant occluding the micropores of the etched enamel surface, providing a protective barrier against caries.
A three dimensional model of tag formed in etched enamel surface where prism peripheries were demineralized preferentially, consisting of a crater-like foundation with a filamentous or filmy extension on it, was proposed to explain the difference observed in tag length between light microscopy and SEM.
