1 A subsidiary of Glidewell Dental Performance Evaluation of CEREC MC XL Milling System Utilizing Obsidian Milling Blocks February 25, 2016. ABSTRACT. The CEREC MC XL mill Performance was evaluated on Obsidian Milling . Blocks using identical IPS CAD/CAM Milling parameters. The results were benchmarked against IPS CAD/CAM blocks in terms of mill/bur Performance and quality of the milled restoration. The CEREC . MC XL mill Performance , handling, servicing and bur wear when Milling Obsidian Milling Blocks were in line with and comparable to that of IPS. blocks. Furthermore, both IPS and Obsidian Milling Blocks gave acceptable final milled restorations. RESEARCHERS. Akash Shreya Shah, BDS, MS. Prismatik Dentalcraft, Inc. Prismatik Dentalcraft, Inc.
2 Vice President, Research Associate Research & Development 18651 Von Karman Ave. 18651 Von Karman Ave. Irvine, CA 92612. Irvine, CA 92612. 991. Performance Evaluation of CEREC MC XL Milling System Utilizing Obsidian Milling Blocks ABSTRACT. The CEREC MC XL mill Performance was evaluated on Obsidian Milling Blocks using identical IPS CAD/. CAM Milling parameters. The results were benchmarked against IPS CAD/CAM blocks in terms of mill/bur Performance and quality of the milled restoration. The CEREC MC XL mill Performance , handling, servicing and bur wear when Milling Obsidian Milling Blocks were in line with and comparable to that of IPS blocks. Furthermore, both IPS and Obsidian Milling Blocks gave acceptable final milled restorations.
3 STUDY OBJECTIVE. In February 2015, Sirona Dental Systems Inc. issued a statement expressing concern over certain materials from Glidewell Laboratories and the possible harm caused to CEREC Milling machines or the possibility of excessive bur wear. The materials named included Obsidian lithium silicate ceramic. The statement expressed no factual basis for the concerns, stating only that Sirona had not validated the materials. Accordingly, the purpose of this study was to evaluate the Performance impact on the CEREC inLab MC XL Milling platform while Milling Obsidian lithium silicate ceramic Milling blocks. The study was performed by the Research and Development and Engineering Services departments at Prismatik Dentalcraft, Inc.
4 , a wholly owned subsidiary of Glidewell Laboratories. STUDY DESIGN. The study was a controlled, randomized Evaluation of the CEREC MC XL Milling system's ability to mill Obsidian lithium silicate crowns. A randomly selected maxillary crown design was milled 347 times over a period of two weeks (February 3 17, 2016). A tooth was prepared for the study and a vinyl polysiloxane impression taken. The stone model from that impression was scanned using the CEREC inEos Blue scanner (Model No. D3446, Serial No. 44427, Part No. 6284264, Manufactured in 2010), a crown was then designed with CEREC software ( ), and Milling facilitated by the CEREC MC XL Milling machine (Model No. D3439, Serial No. 10664, Manufactured in 2008). The designed file was milled 347 times to simulate 26 months of average use by a dentist's office and to evaluate the Performance impact on the mill, while also evaluating the fit and overall anatomy of milled Obsidian restorations.
5 The CEREC MC XL mill Performance Evaluation was monitored by equipment service technicians at Prismatik Dentalcraft. Ten restorations were selected and evaluated by certified dental technicians in the Prismatik Research and Development Department for fit, margin, contacts and overall crown contours prior to and after crystallization. Glidewell Laboratories has milled and processed over 10,000 IPS blocks on CEREC MC XL Milling platforms. Data on mill Performance and bur usage for blocks was aggregated and analyzed for benchmarking against Obsidian Milling Blocks (also know as Obsidian CAD/CAM blocks ). BACKGROUND INFORMATION REGARDING OBSIDIAN CERAMIC. Obsidian lithium silicate glass ceramic from Glidewell Laboratories has FDA 510(k) clearances.
6 The FDA 510(k) approval process is common for dental restorative materials and designates that the material is safe for human use. At the time of publication, 31,302 monolithic Obsidian restorations have been produced by Glidewell Laboratories and delivered to clinicians in the United States with statistical incidence rates similar to other similar materials used in dentistry. 3. OBJECTIVE OF CEREC MC XL Performance TEST. To evaluate the Performance of the CEREC MC XL Milling system for fabrication of Obsidian lithium silicate restorations for preparations requiring full-coverage crowns. KEY METRICS EVALUTATED IN THIS STUDY. Milling time Tool Performance Mill Performance Crystallization Performance Material Performance MATERIAL AND METHODS.
7 Test Material: Obsidian Milling Blocks were milled with a CEREC MC XL system. 347 CAD/CAM blocks (size W14). were used in this Evaluation . The MC XL mill used was Model No. D3439, Serial No. 10664, manufactured in 2008 and used software version Of note, this CEREC MC XL unit was put into service in the laboratory in 2010 and had already milled 8,638 blocks prior to this study. Test Method: One randomly selected vinyl polysiloxane impression from the All-Ceramic Fixed Crown Department at Glidewell Laboratories was studied by R&D. The impression was poured with dental stone and allowed to set for 20 minutes. The resulting stone model was then scanned; a crown designed and milled (Fig. 1). The scanned case followed the manufacturer's protocol for designing and Milling .
8 Crown designs were generated utilizing CEREC . software, version At the time of this investigation, Obsidian Milling Blocks were not listed as a material choice in the CEREC software. As a result, the researchers used the closest material choice available (IPS [Ivoclar Vivadent]), which set comparable parameters for designing and Milling Obsidian restorations. Single-unit Model was Scanned Using inEos Blue Designed Restoration Files ( CEREC software ). Same Designed File was Milled on CEREC MC XL. 347 Times Figure 1: Workflow used 4. SCANNING AND DESIGNING OF CROWN USING CEREC INEOS BLUE SCANNER. AND CEREC DESIGN SOFTWARE A case (stone model) was scanned using the CEREC inEos Blue scanner (Model No. D3446, Serial No. 44427, Part No.)
9 6284264, Manufactured in 2010). A crown was designed and then milled using the MC XL Milling machine. The scanned case followed the protocol of scanning the buccal and occlusal, then lingual and proximal surfaces (Figs. 2, 3). The crown was then designed using CEREC design software. The parameters used for designing were the same as those used for IPS (Fig. 4). Figure 2: Scanning the stone model Figure 3: View of the scanned file for tooth #3 Figure 4: View of the designed crown for tooth #3. 5. Milling OF CROWN USING THE CEREC INLAB MC XL. After employing the design software, an Obsidian lithium silicate block, which is in partially crystallized state, was placed in the CEREC MC XL unit for Milling (Figs. 5 7). Figure 5: Obsidian Milling block seated Figure 6: Occlusal surface of Obsidian Figure 7: Intaglio surface of Obsidian in CEREC MC XL Milling block with CEREC mandrel Milling block with CEREC mandrel under 10x magnification under 10x magnification CRYSTALLIZATION.
10 Obsidian Crowns were crystallized according to the manufacturer recommendations as outlined. The crystallization cycle was approximately 23 minutes long (Table 1). TABLE 1: OBSIDIAN CRYSTALLIZATION CYCLE. Ivoclar Programat CS / CS2, EP 5000 / EP 5010, P Series Stand-by Temperature 400 C. Vacuum Level 1 V11 (On) 400 C. Vacuum Level 1 V21 (Off) 780 C. Closing Time S 3 minutes Holding Time H1 10 seconds Heating Rate t1 90 C/min Holding Temperature T1 780 C. Vacuum Level 2 V12 (On) 780 C. Vacuum Level 2 V22 (Off) 819 C. Holding Time H2 10 minutes Heating Rate t2 40 C/min Holding Temperature T2 820 C. Long-term Cooling L 680 C. Cooling Rate tL 50 C/min RESULTS. Milling time: Obsidian Milling blocks performed well in the CEREC MC XL mill.