Fabrication of an all-ceramic crown by a new method : Second report

Abstract

We previously developed and reported the potential clinical application of a simple, rapid porcelain firing method for the production of copings that does not require special equipment or refractory casts. However, the production method described in that report was based on conventional methods, and had not been evaluated in detail. In this study, we attempted to optimize the production method. We evaluated the powder-liquid ratio, composition of mixed powder, taper angles on the axial plane, holding temperature at firing, and the relationship between the marginal space and firing conditions. We also examined changes in the crystal structure of lithium silicate glass created by the firing, the effect of the sintering conditions on the distance between alumina particles, and the bending strength of the crown at different stages of production. We found the optimal conditions for firing of the porcelain by evaluating the production processes. We were able to produce all-ceramic coping crowns with a marinal gap comparable with conventional coping crowns, and do this within a production time of 160 min.