Abstract
The immature permanent teeth, especially the first molars, show a high caries rate prior to the start of their functioning as teeth. While a sealant is generally applied as part of the system for the prevention of caries, the breaking and falling of of the filling materials are often experienced in clinical treatment. Most of the causes of the unsatisfactory situation in the prognosis are considered attributable to technical errors and to the cleaning of tooth-surfaces, pits and fissures. Therefore, the authors, using a tooth-surface polisher and a fissurecleaning chip, cleaned an extracted human tooth and observed the cleaning effects with SEM. The authors also applied etching to the tooth-surface and to the pits and fissures after cleaning, and observed, with SEM, etching effects that differ according to the cleaning effect. As a result, the following information was obtained:
1. When the tooth-surface was cleaned with a brush-cone, some enamel cuticles remained in the depressed portions but, when a tooth surface polisher was used, the dental cuticles were found to have been removed and the tip of the enamel rod exposed, suggesting the effectiveness of the polisher.
2. When the pits and fissures were cleaned with an explorer and a brush-cone, a large volume of deposits that appeared to be of organic nature was found. However, in the case of cleaning with a tooth-surface polisher, while the deposit that appeared to be soft was observed to have been removed, the deposit apparently in process of calcification had not been eliminated.
3. When the cleaning of pits and fissures was done with a fissure-cleaning chip, it was noted that the deposits had been removed within the reach of the chips and, moreover, some exposed portions of fresh enamel, resulting from the shaving of first-layer enamel, were observed.
4. As to the etching effect on the tooth-surface, it was observed to be greater in the case where there was no remnant of the enamel on the surface-layer to which the tooth-surface polisher had been applied. As was also confirmed from the observation of the surface of a sealant replica, the cleaning effect in the pits and fissures was found to be more certain when the fissurecleaning chip was used.
