Restorations at 35 Minute Intervals Interview with Dr. N. Rohde and M. Bildhäuser

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Whereas production times with zirconium of up to 14 hours are no exception, aesthetically appealing composite crowns can today be created within 35 minutes and only require minimal post-polishing.

The CAD/CAM experts of the renowned laboratory partner DT&Shop know all about the benefits of fast, high quality production and how to keep dental laboratories competitive in the long run. In this interview, Dr. Nicolas Rohde, Head of Digital & International Division, and dental technician Manfred Bildhäuser explain what is possible in the field of CAD/ CAM with state-of-the-art materials research.

Dr. Nicolas Rohde is well acquainted with the notion of speedy deliveries. The fast implementation of demanding customer orders is the daily agenda of the leading mail order company for dental laboratory equipment. Eight dental technicians produce highly aesthetic prosthetics for the company‘s numerous customers in the in-house milling center.

No wonder the enthusiasm for the novel CAD/CAM composite blocs, for example, the BRILLIANT Crios submicron hybrid composite from Swiss dental specialist COLTENE, knew no bounds. The flexible all-rounders make life considerably easier for CAD/CAM production and are notable for their rapid polishability, among other things.

Question: “Dr. Rohde, it is difficult for dentists to bypass composites in classical filling therapy. Now this versatile material is also entering the arena of CAD/CAM technology. Is composite the new ceramic?”

Dr. Rohde: This depends entirely on the indication! Indeed, the CAD/CAM composite blocs currently available on the market bring with them a number of excellent material properties. In many cases it is possible to create visually attractive results from this flexible material in virtually no time. Long sintering or crystallizing of other dental materials can be eliminated completely. After roughly 35 minutes, the milling machine produces virtually finished crowns, partial crowns, inlays, onlays or veneers. Due to the high intrinsic gloss of high performance composites such as BRILLIANT Crios, brief polishing is all that is required. This allows fabrication of a top quality restoration within one hour.

Q: “How did you find out about the reinforced composite blocs?”

Dr. Rohde: Based on our long-standing experience in milling, COLTENE asked us to grind a number of restorations from the material for their acrylic models. Amazingly, of the 700 units which we produced in record time, there was not a single restoration which did not leave the CNC machine in perfect condition. After this convincing result we immediately included BRILLIANT Crios in our portfolio and are already handling first enquiries for the novel material.

Q: “What can composite do which traditional CAD/CAM materials can’t?”

M. Bildhäuser: Above all, the marginal stability of BRILLIANT Crios is extremely high. Compared with glass ceramics, the high performance composite is ideally suited for inlays or onlays requiring extremely thin walls. We also use the flexible material in all cases where preparation was not so good.

Dr. Rohde: From my days in implant dentistry, I know that removing part of the dental fibres for dentures with implants often leads to a lack of the natural damping effect of the ligament in the jaw. This makes it extremely pleasant for patients, if the crown itself has a slight damping effect. Many users have reported on the high wear comfort of composite based restorations. The dentine-like modulus of elasticity provides for a natural chewing feeling and is gentle on the opposite tooth at the same time.

Q: “Where exactly is the specific advantage in processing, Mr Bildhäuser?”

M. Bildhäuser: I was amazed at how easy the novel material could be smoothed and polished. There are no interfering inclusions of the polishing paste and post-processing takes next to no time, be it for monolithic crowns, onlays or veneers, whereby we use a compact wet grinding machine also used by many of our customers. This is not difficult to reproduce even for smaller laboratories: for example, the Finocam W is an inexpensive wet grinding machine which often delivers better results than far more expensive chairside CNC machines.

Q: “What needs to be observed in general terms when processing CAD/CAM composite blocs?”

M. Bildhäuser: Of course every technician has his own style. A somewhat slower speed is generally recommended for composite. It is important to apply only little pressure on the

material. And as the processing time is short anyway, one can take a more relaxed approach. Of course, with a new material one always needs to first try out the pressure effects of the grinding tools.

After one to two units, processing is possible with comparatively little effort. The final finishing and polishing is separated from the carrier with a thin disc. I then smooth the surfaces with a soft rubber polisher. For further processing I use the DIATECH ShapeGuard from COLTENE, this adapts perfectly to the respective surfaces. This is followed by meticulous post-polishing with the margin polishing paste and finished!

Q: “Which material is currently in particularly high demand in laboratories?”

Dr. Rohde: Zirconium remains the gold standard in the industry, last not least because of its favourable price structure. At approximately 25 units per blank, the circular blank is certainly in a different price category than the conventional blocs for chairside grinding systems. At the same time, zirconium has a convincing flexural strength of over 1,000 megapascals. At approximately 600 megapascals the value is of course somewhat lower for highly translucent pieces.

On the downside, zirconium needs to be sintered for a very long period to achieve an aesthetic solution. 14 hours for production is quite common. When using CAD/CAM composite blocs we can process orders from laboratory customers quicker as the firing process is eliminated. If we have the data by 3 p.m., our milling centre can generally deliver on the same day.

Q: “Who benefits most from rapid processing?”

Dr. Rohde: If the dentist has a CAD/CAM device in the practice, a crown can be produced within an hour and be fitted during the same session. The patient saves the need for a second session and is pleased by the immediate treatment. Also in the laboratory, production only takes one hour, in other words: the patient can have his dentures a few days later which is still considerably faster than in the past.

Q: “…does this mean there are no limits to patients‘ demands?”

M. Bildhäuser: Today, patients obtain extensive information via the Internet on various indications and the treatment methods available. This increases the wish for highly aesthetic restorations and patients do take a closer look. In view of the marked quality awareness of many customers, one is of course delighted to deliver work to laboratories distinguished by a fantastic gloss.

Q: “Dr. Rohde, how has the competition from the Far East changed the domestic laboratory market in your opinion?”

Dr. Rohde: As leading mail order company we export to over 100 markets and monitor the development in Europe with mixed feelings. The pressure on margins is no doubt increasing if dentists outsource their laboratory work more and more to India or China. Investment into CAD/CAM technology is therefore a good approach for the individual dental laboratory: machine fabrication largely eliminates the intermediate labour-intensive steps, making production costs competitive again. Usually the unit labour costs are the deciding factor in the calculation.

M. Bildhäuser: Add to this that the starter models for CAD/ CAM have meanwhile become affordable, together with a manageable learning curve. In the past you more or less had to be an engineer to operate the devices, these days dental technicians attend one of our training courses at the beginning, the rest follows automatically.

Q: “And finally: what properties would you want the dental material of the future to have?”

Dr. Rohde: (laughs) The all-in-one solution for every purpose would be a material with the flexural strength of zirconium, the aesthetics of e.max and the processing characteristics of composite, but we place our trust in the inventiveness of the manufacturers. The amazing development of modern high performance composites over the past years would suggest that it is not only processing time in the laboratory which will undergo rapid progress. And we would be pleased to actively support easing the work burden for dental technicians.

Author

Dr. Nicolas Rohde

2002 Business graduate

2005 – 2003 International Business Development at Hopf, Ringleb & Co (HORICO)

2010 – 2005

Work at the Institute for Management at the Free University Berlin, degree Dr. rer.pol.

2012 – 2011 Management HORICO North America LP

2015 – 2012 Vice President Digital Dentistry Systems at the Biodenta Group Since 2016 Division Manager – Head of Digital & International Division at DT&SHOP GmbH

Manfred Bildhäuser

1981 – 1976

Training as dental technician

2005 – 1982

Active in all fields of dental technology, in commercial laboratories as well as practice laboratories

2013 – 2005

Own dental laboratory in Fulda Since 2014 Technician in the DT&SHOP milling centre


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