Abstract
This study was attempted to investigate the effect of acid etchants on normal and carious primary dentin.
Extracted or exfoliated teeth (noncarious: 26 cases, caries extended into the dentin: 8 cases) were used. The morphology of the prepared cavity surfaces, softened dentin removed surfaces and the etched dentin surfaces were observed through a scanning electron microscope. Cavities were prepared dry with the diamond bars, softened dentin was removed with the steel bars and a hand instrument. The dentin was then etched for 1 minute with acid etchants. The following observations were obtained.
1. In the cases of cavities cleaned by water spray alone, the dentinal surfaces were completely covered with a thick smear layer and anatomical details such as tubles could not be seen.
2. In the cases with normal dentin etched after cavity preparation, the dentinal tubles were opened, but the smear layer remained on some parts of the etched dentin. In some cases, small fibers were exposed in the opened dentinal tubles.
3. In the cases with caries decayed dentin, etched after removal of the carious lesion, the dentinal tubles were opened, but the effect of the acid etchants was less than in the normal cases. In many cases, some parts of the intertublar dentin and dentinal tubles were covered with a smear layer. In some cases, most tubles were filled with tubelike, cylindrical, crystallike and amorphous materials even after etching.
