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Introduction
CEREC Primemill™, the latest grinding and milling unit from Dentsply Sirona, represents significant innovation in digital dentistry. Thanks to the latest technology, indirect restorations can be fabricated faster and more easily, resulting in a precise fit using a wider range of materials. The unit can quickly fabricate high quality zirconium and glass-ceramic restorations. The treatment of a patient, whether temporary or final, can be completed within one hour.
Daniel Vasquez, DDS an innovative and respected dentist in California has been working with CAD/CAM and CEREC for 12 years. During that time, he has completely digitalized his practice. As a long-time CEREC® user, Dr. Vasquez and his partner have specialized in general dentistry and same day-dentistry, using numerous digital technologies from Dentsply Sirona. For Dr. Vasquez, working with digital technology means being able to focus on the patient and on the growth and success of his practice. The technology distinguishes the practice and enables him to provide patients with high-quality, functional, and esthetic restorations in a short timeframe. In addition, he has fun experiencing how the individual systems work quickly and seamlessly together while delivering excellent results.
Using a specific patient case as an example, he explains step by step the procedure and advantages of working with CEREC Primemill™ and the impact of digitalization on his practice.
Material and Methods
A 48-year-old female patient lost anterior tooth 11, which had served as an abutment for an existing three-unit bridge on teeth 11-22. We decided to replace the old bridge with a new four-unit bridge on 12-22. Because of significant irritations of her soft tissue, a cleaning and healing under a temporary bridge was indicated. We also prepared tooth 12 as a new abutment tooth. An initial scan was taken using the CEREC® Primescan™ intraoral scanner. The fabrication of the temporary and final restorations was made using CEREC Software and CEREC Primemill™.
We planned to fit the patient with a four-unit temporary bridge in one session. In our dental practice, every extensive treatment is based on a scan with the CEREC® Primescan™ intraoral scanner. Patients can see their oral situation in real time and understand the reasons for a specific treatment. For this patient’s restoration, tooth 21 was built and prepared in the classical way. After preparation, the maxilla, mandible, and buccal bite were recorded with the scanner (Fig. 1-3). Then I designed the bridge directly at the chair. In this way, patients can appreciate the capabilities of the system, but also participate in the decision-making process and thus identify more closely with their new restoration. The suggestions of the software are usually quite good. In this case the patient was satisfied with the shape of her old restoration, and in the case of tooth 21 we oriented ourselves around the shape of tooth 21 because tooth 21 was completely present before preparation.
The digital models were processed, and the automatic preparation limits checked. I slightly corrected and adjusted them intraorally due to the minor asymmetry at 21 in the virtual model (Fig. 4-6). Further adjustments of contours, contacts and occlusion were not necessary. The multilayer composite block was selected for the four-unit bridge temporary, a multilayer polymer consisting of four-color layers for the fabrication of esthetic long-term temporary restorations in the anterior and posterior region. This material was intended to provide more natural esthetics (Fig. 7-8). The milling strategy for milling PMMA was chosen. For the speed, there are three milling programs to choose from: Extra Fine, Fine and Fast. For this case I chose Fast milling, as this is completely adequate for a temporary restoration.
Once the design, material and milling mode had been defined, the milling could begin directly in the practice (Fig. 9-10).
The manufacture of the Four-unit temporary bridge took only 35 minutes. After milling was completed, the temporary restoration was removed from the sprue and anatomically check. The quality of the margins was phenomenal, and the embrasures looked very defined. After one minute of polishing to produce a high luster and shine, the restoration could be placed intraorally for temporary cementation without further adjustments. It fit excellently.
The patient was sent home with the temporary restoration for about three weeks for in situ healing of the gingiva and under the guidance of special hygiene instructions and treatment with chlorhexidine rinses. She was thrilled about the speed and quality with which this temporary restoration could be manufactured. The patient was no longer irritated by the gingiva and the gingival architecture had also been optimized with the temporary restoration.
Conclusion
Milling, and for this case milling PMMA, has never been easier for me than with CEREC Primemill™. The mill delivers impressive results with very smooth surfaces and clearly defined margins. The unit is easy to use and produces restorations in zirconia and glass-ceramics from a wide range of manufacturers at high speed and without compromise on quality. The Fast milling mode require fine polishing. If you select the Fine or Extra Fine milling mode, you can save yourself this step. Thanks to the integration of the CEREC® Primescan™, you also attain exact intraoral scans so that the data facilitates an accurate result.
