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This series of articles provides a panorama of the current state of CAD/CAM technology used by dentists and dental technicians. The first part describes the procedures, data acquisition choices, software, and materials used. It also illustrates the most important cardinal steps in the creation of CAD/CAM technology and offers a basic introductory overview of this technology.
In 2009, MDT Josef Hintersehr, manager of the company Hint-ELs, which is located in the German city of Griesheim, told us: “We at Hint-ELs depend on the same rules as dental technicians in the laboratory: the more information we get from our customers, the better are the results we can deliver! Therefore, we always are receptive to the worries, desires and goals of the dental technicians. In this way, we can identify the trends at an early stage and can offer solutions that provide a competitive advantage for our customers.” With the launch of several highly innovative new products in 2010, he proves that he did not promise too much.
Dental technologists are constantly seeking advances in restorative materials and technology. Zirconia has long been of interest for its exceptional hardness, esthetics and biocompatibility. The combination of these properties and CAD/CAM technology are the driving force behind zirconia’s exponential growth in usage today. This article details two examples of zirconia used in daily practice. A 66 year old woman suffered significant anterior bone loss in an automobile accident. The patient underwent anterior ridge grafting for better implant placement. Implants were placed, allowed to heal and impressions taken for treatment. (Fig.1)
A denture set-up was performed to verify esthetics, lip support, phonics and tooth position. (Figs. 2 & 3)
The denture set-up was duplicated in wax and was reduced before scanning to provide adequate support for ceramics. (Fig. 4)
The wax-up was then scanned and a digital file was created. (Figs. 5 & 6)
The digital file was sent to the milling unit1 to be machined from a zirconia disc2. (Figs. 7 & 8)
The zirconia framework was refined and sintered for 10 hours. Titanium cylindrical interfaces3 were then temporarily luted with resin into the zirconia framework for intraoral try-in. (Figs. 9 to 11)
Once the intraoral try-in of the zirconia framework was approved, the resin and titanium interfaces were removed and tooth colored and tissue colored low-fusing porcelain4 specifically formulated for zirconia was applied and baked to the zirconia framework. (Fig. 12)
The electroformed telescopic technique is an accepted procedure today and is particularly suitable for the restoration of implants because of the tension-free fit. The fixation principle has important advantages compared with conventional friction fit.
The success or failure of CAD/CAM fabricated restorations lies ultimately in the accuracy produced when scanned, and the amount of time it takes to achieve a quality result. There are many types of CAD/CAM scanners currently on the market today that claim to be the ‘ultimate solution’ when scanning dies, models and dental related products to 20 micron accuracy. Terminology like 3+1, 3+2, or even 3+3 scanners indicate combinations of laser and camera configurations, and can be confusing when deciding which scanner to purchase. ‘White light’, ‘Optical’ scanners’ and ‘Laser.’ scanners have most of us even further confused as to what is best. To most laboratory owners, it simply comes down to whether or not the restoration fits the die or model and has great margins. When I asked this question to those who know… I got nearly the same answer; “It is qualitative and the results must be compared to a standard to determine actual accuracy!”
In solving this case the expression “necessity is the mother of invention” is the first thing that comes into mind. Once upon a time the prosthodontic laboratory was a very closed unit in which the prosthesis was made on one site that equipped itself by investing in cutting edge technology. However, with the advent of computerized modern digital technology such as CAD/CAM etc. those laboratories unable to afford the high cost of investment must therefore make recourse to external units in order to get structures made. Consequently, in order to carry out the very same work, the profession has moved from closed units into co-operation with other colleagues. The prosthodontic sector is undergoing “globalization” in which a great deal of energy is being spent in bringing together and comparing different ideas in order to find solutions to complex cases.This article describes a case solved in this way.
The CAD/CAM components of the company Hint-ELs which is located in the German city of Griesheim are successfully employed in a total of 23 countries. Users decide on their own if they want to utilize the broad range of products as a complete solution from one single source or if they opt for single components combined with system elements from a third party provider – a solution enabled by open data interfaces.Progress in focus
Hint-ELs was founded in the year 2000 by MDT Josef Hintersehr (Fig. 1), who has a heart of an innovator and who always wanted to promote advancement in dentistry. In 1986, after having completed his training as a master dental technician, MDT Hinterseher established his own dental laboratory. In 1990 already, he became a precursor in the matter of CAD/CAM by incorporating restorations manufactured in a computer-aided procedure into his business activities. In 1993, he applied for the first patents for the processing of HIP zirconia and the fixture of blanks. Two years later, he began to develop a model scanner and later a complete CAD/CAM system in co-operation with the Fraunhofer Institute for Applied Optics and Precision Engineering (IOF) in Jena (Germany), which is still an important co-operation partner of Hint-Els today. After having founded the company, a fully automated CNC machine and the programming of a software solution for the generation of waterproof data which are essential for the laser sintering technique followed. Today, the product offer of Hint-ELs includes scanners, production units for the milling and the laser sintering technique, software programs and diverse materials. For the year 2009, the introduction of numerous new products has already been announced.
In 2000, the Lava CAD/CAM system (3M ESPE) for crown and bridge restorations was clinically introduced in 3M ESPE’s experimental operatories in Germany. The first university study began in 2001, with 5-year recall results being published in 2006. 1
Six years ago in 2002, after receiving FDA approval, Lava was first introduced into the United States commercially and has become a widely used all-ceramic system.
LAVA is a zirconium oxide based crown coping and bridge framework system that provides for both underlying strength and aesthetics when veneered according to recommended techniques with the appropriate oven-fired layering porcelains. It can serve as an anterior or posterior all-ceramic alternative to porcelain fused-to-metal crowns and bridges in many, but not all circumstances.
This two-part article discusses and presents solutions for the most commonly observed techno-clinical challenges as observed by experienced team members from four different Authorized Lava Milling Centers (ALMCs). ALMCs are responsible for the design and milling production of copings and frameworks. The ALMCs that participated in this endeavor were (in alphabetical order) Colonial Dental Studio in Davenport, Iowa; Dental Crafters in Marshfield, Wisconsin; New Image Dental Laboratory in Atlanta, Georgia; and Issaquah Dental Lab in Issaquah, Washington. The following question was posed as the premise for this article: “What can outsourcing dental laboratories and/or their doctors do to better assist you in providing them with the best possible milled copings and substructures?” The purpose of this question was to gain information that would be valuable in achieving better technical results, improving team relationships through mutual understanding, and, optimizing patient outcomes for those receiving Lava restorations from their doctors.
Dental labs today face constant changes in technology and increasing overseas competition. CAD/CAM technology aims to reduce direct labor cost yet foreign labor remains cheaper. Finding and implementing practical tools of efficiency, accuracy and simplicity into our laboratories to stay competitive and cost effective can be especially tricky when investing in new technology or change.
It’s a great material with endless possibilities for our line of work, a material that according to the author has no match – HIP-ed Zirconium Dioxide. It was introduced into the dental technician production circle about 13 years ago by DCS now Bien Air DCS Solutions. It started with CAD/CAM then the material was introduced: zirconium dioxide. The expectations for this material were well-defined. It had to be a strong, biocompatible, oxide-free and a dimensional accurate material. Unfortunately, the last requirement was not taken into consideration by the manufacturers of CAD/CAM systems.
The same goes for the strength; the reality does not match the expectations according to Prof. Dr. Joachim Tinschert and Prof. Dr. Heinrich Kappert. In 2002 we chose a system that could process zirconium dioxide with dimensional accuracy. A system that was able to mill bridges (27% linear) without any volume reduction which is equivalent to a total space volume of 50%.
We have to point out that it is impressive how cost effective it is to manufacture zirconium dioxide copings from blanks. But let’s be honest! Many times the anticipated “windfall” turned into ruinous price deterioration because a lot of labs offered the same service at a lower price and others had to follow suit to be competitive.
Zirconium dioxide is not a low-grade material! We invest in the future of our employees and our business and yet we do not “praise” this material instead we “dispraise” it. With that being said we should focus on our high investment cost and not degrading ourselves to “coping dealers” who offer zirconium dioxide frames at approximately $74.00 each. If we add our expenses like equipment investment, maintenance contracts, material and energy costs, risk premiums and salaries, I honestly ask myself how some of my colleagues can survive. Maybe they just like to work.
Let’s talk about the work. Once the blank material flooded the market and everybody lowered their prices, we had to rely on our skills to be competitive. We use HIP-zirconium dioxide in our lab – you cannot put a price tag on quality.
Our strength is the ability to manufacture wide spanned, high strength and above all dimensionally accurate bridges. With the ceramic veneers in place we can cement a bridge tension-free onto the galvano framework in the mouth. The skeptics might ask, “Why is cementing necessary if the system is so precise and great?” As dental technicians we have to be aware of all aspects in the job chain, from the impression to the expanding cast or the marginal space between impression copings, lab analog and abutment. Recently, I had a case where I had to unscrew a post from a telescopic bridge that was fitted onto 8 implants. After we screwed it back into place, the patient noticed a slight “wobble”. The solution: prepare a new galvano coping and cement it into the restoration. These things can happen. Personally, I find that the fitting of the tube-in-tube implants is outstanding and cannot be compared to HEX-implants.
This two-part article will discuss and present solutions for the most commonly observed techno-clinical challenges as observed by experienced team members from four different Authorized Lava Milling Centers (ALMCs). ALMCs are responsible for the design and milling production of copings and frameworks. The ALMCs that participated in this endeavor were (in alphabetical order) Colonial Dental Studio in Davenport, Iowa; Dental Crafters in Marshfield, Wisconsin; New Image Dental Laboratory in Atlanta, Georgia; and Issaquah Dental Lab in Issaquah, Washington. The following question was posed as the premise for this article: “What can outsourcing dental laboratories and/or their doctors do to better assist you in providing them with the best possible milled copings and substructures?” The purpose of this question was to gain information that would be valuable in achieving better technical results, improving team relationships through mutual understanding, and, optimizing patient outcomes for those receiving Lava restorations from their doctors.
Part I of this two-part article will deal with challenges presented by dental laboratories that outsource the fabrication of Lava copings and frameworks to ALMCs. In some instances, where the dental laboratory contains both the milling equipment and also finalizes the restorations with fired layering porcelain, they will have likely discovered and solved some of the challenges identified. This is because the problems existed internally between departments within the same laboratory. However, depending on the laboratory, this does not necessarily mean that all the problems presented by their prescribing doctors, such as preparation or impression issues, have been addressed and dealt with successfully. In light of this, Part II (to be published by Spectrum Dialogue in the February 2009 issue) will continue with identification of, discussion of, and proposed solutions for, the challenges that lie within the responsibility of doctors prescribing and preparing cases for Lava restorations. It is still prudent however for doctors that are using outsourcing labs, and not directly sending their work to a full-service ALMC laboratory, to be aware of the issues and solutions as presented in Part I of this article. This is due mainly to the team implications for the success of the finished Lava restorations.
Patients can be picky people. When it comes to cosmetic dental procedures, they often arrive at the dental office with preconceived ideas of what they want their teeth to look like. Just as a person who walks into a hair salon with a photo of what they would like their hairstyle to look like (usually cut from a magazine, and often a picture of a celebrity or someone they admire), patients looking to beautify their smiles have a clear picture of the results theyexpect to achieve.
The patient profiled in the case study presented herein was not happy with her two front teeth, in particular (Figure 1). She did not like the way her centrals were “too long” in relation to the neighboring laterals. Nor did she like the shape— the incisal edges of both 8 and 9 were essentially flat, lacking definition due to composite restorations several years prior due to chips at the mesial of both teeth. Another motivating factor was her husband, who was returning home from active duty in Iraq, and she wanted her teeth to look great for him.