Dimensional accuracy of dental casts: Digital versus conventional impression techniques

Purpose. This study compares the dimensional accuracy of dental casts obtained by intraoral digital impression method using LAVA Chairside Oral Scanner C.O.S. with conventional impression method using polyvinylsiloxane (PVS).Materials and Methods. A polyvinyl silioxane silicone impression material was used to make a complete maxillary final impression of the typodont. The impression was poured with epoxy die. A maxillary complete arch model was prepared to facilitate repeatable measurements. The maxillary master cast with prepared teeth was scanned 15 times with digital scanner Lava C.O. S. PVS impression material was used to make 15 final complete arch impressions of the epoxy master model. The impressions were poured with Type 4 dental stone. Three horizontal and one vertical linear distances were measured on the epoxy master cast and each the 30 conventional and LAVA casts using a digital calipers. Each site was measured ten times on the master model and five times on other models. Independent sample T-test of equivalence in means was used to determine the differences between the groups.Results. When two investigated groups were compared to each other (SLA and Conventional), the results were not statistically significant for every distance. Statistical significances were found on both investigated groups when compared to master model values. This represents a linear change of several microns, which has questionable clinical significance. All deviations in casts were within a clinically acceptable range.Conclusion. Accurate dental casts can be made with either conventional impression or digital impression techniques. A decrease in the accuracy might occur with both conventional and digital scanning methods if the procedure is not properly managed. Future research is needed to assess a full potential, which lies in digital impression systems.