Magister Scientiae Dentium - MSc(Dent) / The aim of the study was to assess the dimensional accuracy of Gypsum models following chemical disinfection of the impressions and to compare it with the accuracy of gypsum models exposed to microwave irradiation disinfection. Results indicated that the dimensional accuracy of the gypsum models disinfected in a microwave oven did not differ significantly from models in the control group. Except for models produced from SS white (SS White group, England) impressions where models irradiated in microwave exhibit significant improvement in the dimensional accuracy when compared with control group. / South Africa