The Influence Of Framework Design On The Fracture Strength Of Zirconia Crown

Research purposes:This study investigated the strength of zirconia ceramics and its decorative ceramics from the morphological design of basal crowns,and explored the effect of several anatomical basal crown morphologies on compressive strength of zirconia all-ceramic restorations.The optimal basal crown design improves the flexural strength of zirconia all-ceramic restorations and provides a theoretical basis for its wider clinical application.Research methods:A normal form of isolated maxillary premolars was selected,conventional methods were used for dental preparation,silicone rubber impression materials were taken,and photocurable composite resin was filled in the impression layer and then cured to remove the resin type to form 28 resin types.The computer-aided design/computer aided manufacturing(CAD/CAM)technique was used to design and fabricate a zirconia ceramic basal crown.The thickness of the basal crown was 0.50 mm.The basal crown was designed into four groups: Group A neck The height of the ring is 0.00 mm,the height of the collar of the group B is 1.00 mm,the height of the collar of the group C is 2.00 mm,and the highest point of the collar of the group D is the high position of the profile,7pieces in each group,a total of 28 pieces.The zirconium oxide crown was cemented to the dental prosthesis with a resin adhesive(DMGPerma Cem 2.0,Germany)and allowed to stand at room temperature for at least 24 hours.The universal load tester was used to test the fracture load.The damage morphology was observed by a bulk microscope and scanning electron microscope and analyzedresult:1.The mean values of the rupture loads in Groups A,B,C,and D were 1.56 KN,1.83 KN,1.95 KN,and 2.27 KN,respectively.After one-way analysis of variance was used,the results showed that the fracture load values of the four groups were statistically significant.Differences in learning,p = 0.04.After multiple comparisons,the results showed a statistical difference between group A and group D,with no statistically significant difference among the other groups.2.The zirconia all-ceramic crowns were broken porcelain and porcelain removed.The χ~2 test was used to compare the composition ratios of the four groups.The results showed that there was no significant difference in the composition ratios of the four groups.Conclusion and significance:The morphological design of the basal crown can affect the bending strength of the zirconia all-ceramic crown,and the flexural performance of the zirconia all-ceramic crown is significantly improved when the height of the collar reaches the high point of the contour.