A dental furnace (10), with a furnace head (including firing space 16) and a firing space bottom (12) is provided which is suited to accommodate a dental restoration part (40). At least one optical sensor (22) is positioned at the dental furnace (10) or in its vicinity, which sensor comprises an output port (26) which is connected to an evaluation device for evaluating the dental restoration part (40) and/or a muffle (14) and/or a press plunger (52) and/or a firing-charge carrier as far as its dimensions and/or its shape and/or its position are concerned.