Evaluation of the effects of slurry water immersion on the surface roughness of ADA type III and type IV dental stone casts

Objective: surface properties of dental casts have critical importance in dental laboratory procedures. however, surface properties of the dental cast are affected by several applications in dental laboratory. one of these applications is the slurry water immersion of the dental casts in some techniques such as preparing casts for duplication. thus, the aim of the present study was to compare the effects of slurry water immersion and tap water immersion on the surface roughness of type iii and type iv dental stones. material-method: sixty master stone blocks were prepared with type iii and type iv dental stone. half of the each specimen group was immersed in slurry water and the other half in tap water for 30 minutes. each of four groups was then allowed to dry for 24 hours without any contamination to the surface of stone blocks. the surface roughnesses of the specimens were determined using a profilometer. the data were statistically analyzed using one–way analysis of variance (anova). results: specimens immersed in tap water showed statistically significant surface roughness (p<0.05) than those immersed in slurry water. the difference was more prominent between ada type iii dental stone groups. discussion: slurry water dissolved the surface of gypsum cast less than tap water. thus, within the limitations of the present study, it can be suggested that, to maintain the surface accuracy of the dental casts, slurry water immersion should be preferred instead of tap water immersion.