It is planned to make a metal-ceramic crown supported by stump inlay of the 23 tooth. Objectively: the crown of the 23 tooth is decayed down to the gingival edge. Root canal is filled to the top. The dentist made a wax stump model with a pin, cast it in metal, fitted it to the tooth, fixed it by means of visphat-cement and got a working plaster impression. At what stage did he make an error?