[Dimensional changes in metal ceramic bridges due to the burn off process].
Six-part bridge frames constructed from the same were examined with microscopic measuring techniques to determine the influence of the fusing technique on porcelain. In the course of this study, it was established that alterations in the dimensions of the bridge frame develop with the oxide bake as well as also the dentine and glaze bakes, while only slight alterations were observed with the basic bake. The oxide bake leads to a general reduction in lumen size of the abutment crown and a decrease in the flange angle; the dentine and glaze bakes, to a deformation of the abutment crowns, mesiodistal decrease in lumen size and buccolingual widening, as well as further reduction of the flange angle. The alterations ranged between 10 micrometer and -63 micrometer and therefore are responsible for the inaccuracy of fit of porcelain-fused-to-metal bridges.