Evaluation of CAD/CAM Generated Ceramic Post & Core

[摘要] ObjectiveThe purpose of this study was to evaluate the use of CAD/CAM technology as a method to fabricate a single-unit, all-ceramic Post & Core restoration.Materials and MethodsThree master dies were fabricated from polymer material (Acadental T Endo TM series RT _AE401_08 ®). The coronal part of the die simulated an ideal core preparation with a 1.5 to 2mm ferrule. The intracanal space of the first die was prepared for a post length of 5mm. The intracanal space for the second die was prepared for a post length of 10mm. Finally, the intracanal space for the third die was prepared to a length of 14mm. Each die was scanned 20 times using the Sirona CEREC AC BlueCam®. A total of sixty e.max® CAD/CAM post and core restorations were milled using Sirona CEREC three compact milling unit®. The restorations were evaluated for precision of fit using 2 methods: 1. The marginal gap was measured for each Post & Core restoration using scanning electron microscopy to determine the accuracy of fit of the core to the die. Measurements were made at three points: mesial, buccal and distal of each sample. The mean marginal gap for the three groups was 38 um.2. A radiograph was taken of each of the 60 samples to determine the post length.The mean post length for the group that was calibrated for 5mm was 6.3mm. Mean post length for the group that was calibrated for 10mm was 10.0mm. Mean post length for the group that was calibrated for 14mm was 11.0mm.Overall, there was no pattern of relationship between marginal gap and post length among the three groups. ConclusionThis study concluded that the focal working length of Sirona CEREC AC® BlueCam is accurate up to 13.7mm. However, the technology is not able to consistently produce accurate milled post and core restorations beyond 11mm. The mean marginal gap for the three groups was 38 um. Future studies are needed to evaluate the biomechanical properties of ceramic Post & Core restorations.

[发布机构] the University of Pittsburgh