IADR Abstract Archives
Fitting Accuracy of CAD/CAM Fabricated Lithium Disilicate Glass-Ceramic Restoration.
Objectives: Lithium disilicate (LDS) glass-ceramic restorations, especially fabricated by CAD/CAM technology, have recently become popular because of its high strength and aesthetics. Fitting accuracy is important for the longevity of restorations. Lower fitting accuracy causes the poor fitting of the restoration to abutment tooth, which increase the risk for clinical failure. The aim of this study was to evaluate the fitting accuracy of LDS glass-ceramic block fabricated by CAD/CAM.
Methods: Initial LiSi Block (GC, LS), and IPS e.max CAD (Ivoclar, EM) were tested. Molar abutment tooth model was scanned using Aadva Scan D2000 (GC), and crown was designed by DentalDesigner (3Shape) with 80μm of cement space. Three crowns for each material were ground by using CEREC MC-XL (Dentsply Sirona). Each crown was scanned using 3D shape scanning machine (ATOS, GOM). Fitting accuracy was compared by superimposing the scanned crown data and the original STL data. Difference of superimposing data was calculated and histogram was created. Percentage of the area over 80μm was calculated. Crowns made by EM were crystallization fired by Programat EP5000 (Ivoclar) by following the manufacturer’s instruction. Crystallized EM crowns were measured using ATOS again. The data was statistically analyzed by one-way ANOVA and Tukey’s test (p<0.01).
Results: Table shows the results of percentage of area over 80μm. Smaller value shows better fitting accuracy. Accuracy of LS was at same level with EM before crystallization firing. However, fitting accuracy of EM significantly increased after crystallization firing. This may due to the deformation of restoration caused by crystallization firing.
Conclusions: Fitting accuracy of LS was higher than crystallization fired EM. It is suggested that LS has better longevity due to higher fitting accuracy.
Methods: Initial LiSi Block (GC, LS), and IPS e.max CAD (Ivoclar, EM) were tested. Molar abutment tooth model was scanned using Aadva Scan D2000 (GC), and crown was designed by DentalDesigner (3Shape) with 80μm of cement space. Three crowns for each material were ground by using CEREC MC-XL (Dentsply Sirona). Each crown was scanned using 3D shape scanning machine (ATOS, GOM). Fitting accuracy was compared by superimposing the scanned crown data and the original STL data. Difference of superimposing data was calculated and histogram was created. Percentage of the area over 80μm was calculated. Crowns made by EM were crystallization fired by Programat EP5000 (Ivoclar) by following the manufacturer’s instruction. Crystallized EM crowns were measured using ATOS again. The data was statistically analyzed by one-way ANOVA and Tukey’s test (p<0.01).
Results: Table shows the results of percentage of area over 80μm. Smaller value shows better fitting accuracy. Accuracy of LS was at same level with EM before crystallization firing. However, fitting accuracy of EM significantly increased after crystallization firing. This may due to the deformation of restoration caused by crystallization firing.
Conclusions: Fitting accuracy of LS was higher than crystallization fired EM. It is suggested that LS has better longevity due to higher fitting accuracy.