Methods: Eight patients came to the Osaka Dental University Hospital each of whom had a single posterior prosthetic tooth, were selected. Two impression techniques were the dual-arch impression and the conventional techniques. The dual-arch impression technique was taken by using only silicone impression material. The conventional technique was taken by using silicone impression material to obtain an impression of abutment teeth and using alginate impression material to obtain an impression of antagonistic teeth. Two impression techniques were performed for one patient. Impression making order was carried out based on the allocation table. Crowns were manufactured in accordance with the conventional technique. Two evaluators evaluated by two crown manufactured by the dual-arch impression and the conventional techniques. The evaluation criteria were proximal contact, margin integrity, crown height, amount of occlusal adjustment and occlusal adjustment time. Each evaluation criterion was compared between the dual-arch impression and the conventional techniques. Proximal contact and margin integrity were analyzed for significant differences using the Wilcoxon test (p<0.05). Crown height, the amount of occlusal adjustment and occlusal adjustment time were evaluated using the paired t test (p<0.05).
Results: There were several significant differences between the dual-arch impression and the conventional techniques (p<0.05). In dual-arch impression technique, proximal contact became loose. Crown height was lowered. The amount of occlusal adjustment was reduced. Occlusal adjustment time was short. There was no difference on margin integrity.
Conclusions: These data suggest that the dual-arch impression technique has high clinical usefulness.