Wednesday, November 7, 2012

Efficient All-On-4 Conversions

The All On 4 Immediate Hybrid Technique is becoming an increasingly popular restoration. ROE has been closely involved in this process from the very beginning and provides complete restorative support from surgical guidance and in-office lab support to the final hybrid design and fabrication. Typically, the final restorative process is a five- or six-appointment sequence, preliminary impressions, final impression, a bite registration and fit verification, tooth try-in, a bar try-in, and seating. We have developed a new streamlined process that eliminates half of these original steps.

This technique requires one of two approaches. One option has the dentist perform a pick-up impression of the provisional, and articulate the master casts in the office. The second option requires the doctor to send the picked-up provisional to the lab to be mounted and finished, leaving the patient without the provisional for 2-3 days. Alternatively, arrangements could be made to have the patient bring the records to the laboratory to expedite the process to one day or less.

To complete the pick-up, long open-tray screws must be used. Also, if the pick-up impression is compromised during the separation procedure, an alginate study cast must be captured so we can duplicate the set-up. If you are interested in more information on this technique, Joe Ambrose CDT (ext 303) will be happy to discuss it with you, or may simply request the Modified All on 4 Technique sheet.

Digital Impressions Now Affordable !

What would you pay for a digital impression machine? Over the past several years we’ve had countless conversations with dentists on this particular question. Until now most doctors agree the technology is here to stay but the price is too high, and they prefer to ‘stick with conventional impressions’. We would like to introduce True Definition Scanner, a $11,995, second generation, digital impression scanner from 3M.

3M is not new to the digital impression market. Its first generation scanner, the Lava COS, was very effective. However, the company has made several improvements that involve hardware changes, resulting in a totally a new machine. The new scanner offers an ergonomic, cleansable, stainless steel wand that is simply tapped with the index finger to power. The wand is smaller than any other on the market, close in size to an intraoral camera, and scans with a smooth, flowing motion. The system is controlled by a touchscreen monitor. The size of the overall scanner is smaller than the previous version, offering more mobility in the office. We are very pleased with the software update, which is open-source, allowing our laboratory the ability to import directly into our iRis digital workflow. Although a powder is still necessary, a very light dusting is all that is required.

This new scanner uses the same “3D-in-motion” process as the last version, which captures video-scans and allows simultaneous viewing on the monitor. Wicher J. van der Meer, (Assistant Professor, Department of Orthodontics, University of Groningen, The Netherlands)  et al conducted an independent study published in August of this year in Plos One. In this in vitro study, implant abutment replicas were scanned on full arch models. The files were imported into an industrial reverse-engineering software called Rapidform for comparative measuring. In a controlled environment, the scans were performed by an experienced dentist following the manufacturer’s scan-protocols. They concluded that this scanning technology is 3x more accurate than the other two scanners on the market. To request a demonstration in your office please contact Alan Banks ext 306.

Zirconia & Phosphates Don’t Mix

Don’t let phosphates contaminate your zirconia. Phosphates, in the form of phosphilipids, are found in saliva. They are attracted to zirconium oxide and create a reaction that affects ‘bonding’. Phosphilipids cannot be rinsed with water or phosphoric acid, which is actually full of phosphates. Therefore, following a try-in of a zirconia restoration that has contacted saliva, it is recommended that you use a zirconia oxide solution called Ivoclean from Ivoclar. This 20-second process optimizes adhesion by drawing the phosphate groups away from the oxides and leaving a fresh bonding surface for priming and/or cementing.

NEW CAD/CAM Provisionals

Digital dentistry is the hot topic these days in both publications and lectures - and for good reason; it’s the future of dentistry. Hardware technology and software programing are moving forward at a torrid pace and are actually evolving faster than the industry’s ability to absorb. At ROE we work hard to stay current on digital technology, providing our clients industry- leading restorations manufactured to the highest standards. Currently, through our iRis system, we digitally produce over 65% of our products, and every month find better ways to fabricate restorations with this technology. We have been anxious to convert our manufacturing processes because digital technology allows us to produce stronger, more consistent and precise restorations with faster turnaround times, often at a lower cost. We have recently moved the fabrication of our provisional restorations into the digital age with results that you’ll be excited to learn about.

Virtual Diagnostic to be Milled In PMMA
Laboratory fabricated provisionals have always presented challenges - the need for chairside additions, relining with limited material thickness, and insufficient material choices, all inhibit optimal esthetics and strength. Denture teeth bonded together with acrylic are esthetic, but usually do not offer long-term strength. Light-cured composites are a possibility; however, they can be difficult to reline and even harder to add-to or modify chairside. Processed acrylic has traditionally been the best compromise.
With the use of CAD/CAM technology, ROE is now offering provisional restorations fabricated from a special dense, porosity-free polymethylmethacrylate commonly called PMMA, which is milled in our industrial milling machines. Technicians use our powerful CAD system to design ideal anatomy and contours with materials much stronger than hand-mixed acrylic.
The benefits extend beyond strength and contours. Using our CAD/CAM system we can digitize a preoperative model or diagnostic wax-up and superimpose it over a study cast. This process allows us to maintain beneficial contours and precisely duplicate a patient-approved diagnostic work-up. Due to the strength of the material we are able to mill single unit shells and even full arch bridges as thin as 1/2mm. Once the milling is complete we characterize the units with stain and, when needed, customize with layering materials, particularly when incisal translucency is requested.

When extra-strong, long-term provisionals are required, these shells can be reinforced internally with a CAD metal substructure. Both the outer shell and the inner reinforcement are fabricated using the same digital technology. Due to the accuracy of the fabrication process, the combined layers can be made thinner than hand-fabricated, metal-reinforced temporaries. We also recently started using alternative reinforcement materials in lieu of cast metal. Fiber reinforcement (FiberForce) and Polyetheretherketone (PEEK) are durable materials with high flexural strength. And, since both are white, they can be easily hidden within the provisional. Our fees for provisional restorations with this technology remain a bargain - just $30 per unit or $65 per unit with either  of the reinforcement options.