A comparative study of the strength of aluminous porcelain jacket crowns constructed with the conventional and twin foil technique

Abstract

The purpose of this study was to evaluate and compare the strength of aluminous porcelain jacket crowns made in the following manners: (1) the conventional technique, (2) the conventional technique with a pure alumina insert, (3) the twin foil technique, and (4) the twin foil technique with a pure alumina insert. The conclusions of this investigation can be summarized as follows: 1. Porosity was observed in all the restorations made by each of the techniques. 2. The porosity was greater at the porcelain-platinum foil interface than anywhere else throughout the restoration with both the conventional and twin foil techniques. 3. The porosity seemed to be evenly distributed along the interface, with no concentration in any area. 4. Regardless of the technique, crowns that were more porous fractured at lower values. 5. Crowns built by the twin foil technique were significantly more porous at the interface of the tin-plated platinum and the porcelain core than those built by the conventional technique. 6. Crowns constructed with the conventional technique were significantly stronger than those constructed with the twin foil technique. 7. There was no bond between the core porcelain and the platinum foil matrix in crowns constructed by the conventional technique. 8. There seemed to be a strong bond between the core porcelain and the tin-plated platinum matrix in crowns built by the twin foil technique. 9. The presence or absence of the alumina insert on crowns constructed with the conventional and twin foil technique did not affect the strength of the crowns when tested at the incisal edge.