that are normally intended to disperse light in order to provide advantageous effects in terms of appearance in the context of the invention the particles have the advantage of increasing surface irregularity the second layer is then fired the layers of ceramic material are fired at a temperature of about 970 u00b0 c to 980 u00b0 c the high temperature operations are then over since the remainder of the method can be performed at a temperature close to ambient temperature although the particles of the last layer of ceramic opaque give rise to a rough surface it is advantageous to give the surface even greater irregularity by sandblasting e g using particles of alumina after cleaning the surface irregularity is increased by etching this can be performed for example by means of a 9 5 hydrofluoric acid solution for 4 min or by means of a 4 hydrofluoric acid solution for 6 min or by the u201c super etch u201d solution of the u201c porcelain system u201d kit from the supplier mirage dental products the surface of the ceramic material is finally treated by being rinsed in steam the intermediate interface is then made by applying an organic silane e g a methacryloxypropyltrimethoxy silane applied by means of a brush after drying an organic bonding layer compatible with the new generation composite material is applied by way of example it is possible to apply in succession two layers of a u201c one step u201d material from the supplier bisco each layer being polymerized for 30 seconds s thereafter an.