Disinfection of dental impressions and occlusal records by ultraviolet radiation.

As chemical disinfection of dental impressions may cause adverse effects on materials and the dental personnel this study examined disinfection by ultraviolet radiation. Alginate, addition silicone rubber and red wax contaminated by Streptococcus salivarius, Fusobacterium nucleatum and five other bacteria in different suspension media were radiated for up to 18 min, and the number of colony forming units was compared to non-radiated controls. The effect of ultraviolet radiation differed among bacterial species and depended on the organic content in the suspension. Generally, the bacterial reduction after ultraviolet radiation was below 4 log steps and thus insufficient for disinfection of dental impressions.