Chemical products for dental and dental-laboratory purposes (as far as they belong to class 5); adhesion promoters, coating materials and masking materials such as protective varnishes of ceramics, metal or plastics, especially of photo-curing plastics for dental and dental-laboratory purposes; auxiliary substances especially diluting agents, mixing agents, binding agents, dyes (pigments), accelerating (curing) agents, as additives for synthetic dental materials and dental ceramic materials; separating layers and intermediate layers of plastics, ceramics, or metal, specifically oxide layers, oxide-forming substances such as chloride and sulfate solutions, specifically tin chloride, copper chloride, cobalt chloride, and nickel chloride for dental and dental-laboratory purposes