Abstract
To solve the drawback of poor esthetics with readymade metal crowns applied to primary molars, the author made, on an experimental basis, a new crown for which the color was a natural color similar to nylon 11, a polyamide resin made of polymer, developed rapidly in recent years for the surface on titanium readymade crowns. In this study, the experimental readymade metal crown for primary molars esthetics into consideration was coated with using nylon the fluidized bed coating method after blast treatment and was examined evaluate tensile shearing, friction, surface roughness water absorption and stain tests to investigate the clinical test. The results obtained were as follows.
1. The tensile shearing strength was shown to be 17 MPa as the maximum value and shown to be 10MPa after 5000 thermal cycles, which indicated it could be easily used for clinical application. Also, delaminating was not seen using the bend examination, and the utility of the blast surface treatment was suggested for the gluing of titanium and nylon.
2. The degree of stain on the nylon coating was similar to that of the self-cured resin, and the disappearance of the stain after brushing was easily compared with the resin, which seemed to maintain the oral esthetics.
3. Since the operation of cutting, countering and polishing of the new metal crown coated with nylon for primary molars were as easy as those for ready made metal crowns on the market, the author has succeeded in the development of a ready made metal crown for primary teeth taking esthetics into consideration.
4. It is clear that the developed esthetic crown with a nylon coat is available for clinical use without impairing the advantages of readymade metal crowns for primary molars
