The Effect Of Different Impression Materials On Accuracy And Retention Strength Of Casting Post

Objective To evaluate the effect of different impression materials on accuracy and retentionstrength of casting post.Materials and Methods 4 impression materials were compared: Agar/alginate impressionmaterials; Clotene condensation cured silicones impression materials; 3M polyether impressionmaterials; DMG vinyl polysiloxane impression materials. Using 4 kinds impression materials totaking a simulate incisor tooth root impression. There are 5 samples in every group. Thedimensional accuracy between the casting post and the inside of root canal at four differentpositions were determined by traveling microscope measuring method. 20 simulate incisor teethroots were made and divided into 4 groups. Using 4 impression materials to make impression andcasting posts. Then the retention strength was measured by omnipotence experiment equipmentafter bond.Results①DMG vinyl polysiloxane impression materials were demonstrated the best accuracy.Among every two groups there was significant difference (P＜0.01).②DMG vinyl polysiloxaneimpression materials were demonstrated the best retention strength. Among every two groupsthere was significant difference (P＜0.01).Conclusions There are significant effect of different impression materials on accuracy andretention strength of casting post. DMG vinyl polysiloxane impression materials is demonstratedthe best accuracy and retention strength. To the casting post, its accuracy is better; its retentionstrength is better.