Trueness of CAD-CAM fabricated frameworks and crown restorations
Mustafa Barış Pomay, Prof. Doğu Ömür Dede
Ordu University, Faculty of Dentistry, Department of Prosthodontic
Objectives
The present in vitro study aimed to examine the trueness of different frameworks and crown restorations using subtractive and additive Computer Aided Design - Computer Aided Manufacturing (CAD-CAM) fabrication techniques.
Materials and Methods
A typodont maxillary left first premolar tooth has been prepared with 1.5 mm occlusal, 1 mm axial reductions and chamfer margin configuration and scanned using an intraoral digital scanner. The data were transferred into a Standard Triangle Language (STL) file format and a crown, and a die model design were made using dental design software with a 50 μm cement space gap. This STL file of crown saved as the reference STL (R-STLc) and crowns were fabricated by using 2 additively (AM) (Crowntec, AMC_CT], C&B [AMC_CB] and 1 subtractively (SM) (DuoCad [SMC_DC]) manufactured resin-based materials (n=10). The STL file of the framework (R-STLf) was also saved, and specimens fabricated using one additively (Co-Cr alloy [AMF_CoCr] and 2 subtractively (AG PEEK, SMF_PE; Romatitan, SMF_Ti) manufactured materials (n=10). All restorations were digitized by using an intraoral scanner to generate test scan-STLs (T-STLc, T-STLf). T-STLs and R-STLs were imported into a 3D inspection software (Geomagic Control X v.2018.1.1) and the deviation analyses were calculated to reveal trueness values. Data were analyzed by using one-way ANOVA and Tukey-HSD tests (α=.05).
Results
The deviation values of SM crown and SMF_PE framework groups were significantly lower than AM contra parts (P<.05).
Conclusions
The SM crown restorations will have a better fit on the SM frameworks than the AM crowns. It is thought that AM restorations will have better trueness values when the printing technologies are developed by researchers, and production with 3D printers is promising, considering the advantage of rapid prototyping