Contact sensitization to metals in dental exposures in Bulgaria

The purpose of this study was to evaluate the incidence of contact sensitization to metals used in dental practice among students of dental medicine, students from a dental technician school, dental professionals and patients. A total of 128 participants: 28 dental professionals, 40 students of dental medicine, 38 students from a dental technician school and 22 patients without occupational exposure to metals, were patch tested with potassium dichromate, cobalt(II)chloride hexahydrate, copper(II)sulfate pentahydrate, palladium(II)chloride, aluminium(III)chloride hexahydrate, gold(I)sodium thiosulfate dehydrate, tin and nickel(II)sulfate hexahydrate. The main metal allergens for students of dental medicine were cobalt(II)chloride hexahydrate, gold(I)sodium thiosulfate dehydrate, nickel(II)sulfate hexahydrate and potassium dichromate; for students from the dental technician school – cobalt(II)chloride hexahydrate, nickel(II)sulfate hexahydrate and gold(I)sodium thiosulfate dehydrate; for dental professionals – cobalt(II)chloride hexahydrate, palladium(II)chloride and nickel(II)sulfate hexahydrate, and for dental patients – cobalt(II)chloride hexahydrate, nickel(II)sulfate hexahydrate and copper(II)sulfate pentahydrate. There was a significantly higher incidence of sensitization to potassium dichromate (χ2 = 10.497, p = 0.012), palladium(II)chloride (χ2 = 5.381, p = 0.02) and gold(I)sodium thiosulfate dehydrate (χ2 = 6.347, p = 0.018) in the group of students of dental medicine. Our findings confirm the importance of cobalt(II)chloride hexahydrate as contact sensitizer for all the studied groups. Students of dental medicine could be defined as a group of particular risk of contact sensitization with metals. We recommend that knowledge on the sensitizing properties of metals be provided at the very beginning of the course of practical education in dentistry, together with application of adequate preventive measures