[The ceramic-tooth margin in ceramometal prosthesis. A comparative study of three fabrication procedures].

This study of the ceramicbutt joint in metal-ceramic prosthesis permits to compare three different laboratory procedures. With the results obtained with two reading processes (numerical measurement and direct measurement of image replicas of S.E.M. to evaluate the marginal gap, it is possible to confirm that: the gold foil method gives the thinnest gap (between 32.7 and 44.7 micrometers) with presence of overcontoured margins. The ceramicbutt joint made by duplicate method, in refractory material, proves to be larger (between 57 and 67.8 micrometers) with overhanging margins, and damaged by sandblasting. The direct elaboration method, on a plaster model, proves to be less precise (gap between 74.6 and 80.4 micrometers) with a round but glossy ceramic margins.