[Cracks in the dental enamel caused by sensitivity testing with CO2 snow and dichloro-difluoromethane--a comparative...

With the aid of permeating dye and standardized fluorescence UV-photography, the reaction of subjects and enamel to the application of two pulp vitality testing methods (frozen carbon dioxide and Frigen -pellets) was examined. The enamel lamella system, the diffusion of temperature changes through the tooth crown and the thermodynamic pattern of enamel and dentine are described in detail. Structural changes of enamel as well as the subject's reaction times to a cold stimulus during the vitality tests are documented and the data are compared. Frigen caused less enamel changes than did frozen carbon dioxide. The subject's reaction times were similar for both methods. There were no differences between the methods with regard to the number of reopened, extended and newly created enamel fissures. However, the length, width and depth of these fissures proved to be less pronounced for Frigen than for carbon dioxide. Clinical implications of the results are discussed.