I have been involved in the field of dental technology for over 40 years and I have witnessed many changes in how we, (the dental mechanics of the ’60s, the dental technicians of the ’80s, and the technologists of the 21st century) deliver our products and services to the dental health professionals for the welfare of their patients.
As the dental schools removed the “fabrication” aspect of dental restorative techniques from their curriculum and the “dental technology programs” educated better and more knowledgeable “technicians/technologists” the entire picture of inter-professional collaboration changed dramatically. Teamwork between the members of the different branches of the dental health care professions for the welfare of the patient is primordial. And now with the reduction in dental technology programs, especially in the USA where are we to find these highly trained and competent individuals? The answer is Computer Assisted Technology Systems.
Dentistry being a rather small market has been slow in receiving advanced technology as a rule. A large portion of our technological advancement came and comes from other successful advancements. For example: bonding came from the aerospace industry, press-able ceramics came from the space program, CAD/CAM came from the manufacturing industries, etc.
Let’s look at what we have to work with now and what is in the near future. The dental laboratory of today is about to change dramatically and you and your patients will be affected.
In the past decade we have been in a position to offer some advanced technology in the fabrication and delivery of dental restorations for the betterment of prosthetics. Yet we still relied on very conventional approaches.
We now have the ability to design substructures for traditional PFM crowns and bridges on a computer and mill it out of a block of plastic or doing a 3D wax print for casting in noble and high noble alloy using the conventional lost wax technique. Combining this approach by using an induction vacuum/ pressure casting system we are able to improve the quality of the cast component and the adhesion qualities of the alloy for the porcelain veneering by the elimination of turbulence created by a centrifugal casting method, as well as eliminating the dangers of carbon inclusion and modification of the alloy that can occur with a torch melt.
Once these bridge frames or copings have been completed we have the options of building porcelain or composite in a conventional fashion, wax to full contour and press ceramic or scan, design, mill and then press.
There are also several other materials that can be milled, sintered and either stained and glazed or received a porcelain layering or pressing, such as zirconia, alumina and lithium discilicate.
Another fabrication method entering the field of dentistry is rapid prototyping where a material is laser sintered by layer to create a coping out of alloy for addition of a veneering material or a plastic material for casting.
The addition of digital impression builds on these developments and removes potential elements of error from our current conventional ways, such as external influences on the impression material, incorrect powder/liquid ratio for the die stone and expansion of the die stone, influences on the wax pattern, expansion factors of the investment material and influences of the casting process, not to mention the finishing of the cast item.
Digital impressions (iTero — Cadent & Bronte 3M) have proven to be a “God Send” so far. The dental health care professional can see his/her preparation “on screen” and review any area that is not appropriate for the proposed or intended restoration, giving you the ability to correct the problem before the impression is finalized and avoid the dreaded call from the lab. This saves on stress, chair time and loss of confidence.
The dental technologist of tomorrow will still trim the dies, wax-up and design the restorations but virtually rather than physically. Although most systems offer extensive libraries of anatomical shapes, a knowledgeable technologist is still required to make the necessary anatomical changes to fit the mouth where this restoration will be placed. Also, through his/her knowledge the technologist will be able to assist and advise in the selection of the most appropriate material for the treatment of each individual patient.
CAD/CAM technology in dentistry is advancing daily and will assure a more consistent result in all restorationa through the reduction of human errors. The efficiency of these systems will allow continued delivery of high quality dental restorations at an affordable rate. One must remember that no single system can answer every needs of the precious patient.
CAD/CAM systems are expensive and limiting; therefore, no single laboratory/technologist can offer a full range of services “In House” as we have been accustomed to over time. Most laboratories/technologists currently “outsource” some of their work to “milling/manufacturing” centres. The biggest players now are: Procera, Astra-Atlantis, Biomet 3i, Straumann, and BioCad, with many more to enter the field in a near future.
What is happening?
The current trend in the US is that laboratory groups are concentrating production facilities in one location with all members of that specific group forwarding a specific product to that facility. This phenomenon already exists in Canada with large laboratory groups.
One cannot expect his/her laboratory technician to be best at every aspect of every technology, but one should be confident that his/her technologist would avail himself/herself of the best source to address the situation.
Reports on the digital impression technology demonstrate a near 0% remake factor, a reduced chair time seating of restorations and a negligible occlusal adjustment time, regardless of CAD/ CAM or conventionally produced restorations.
What is the impact on the dental practice?
Impeccable preparations and tissue management is still the norm.
With intra-oral digital impressions, the practitioner now has the advantage of looking at his/her preparation and occlusal clearance in a 360 view, with the possibility of making corrections before sending the digital imv pression to the laboratory.
The elimination of several human controlled chemical reaction processes affected by time, temperature and environmental conditions are reducing the margin of potential error in several steps of fabrication. Machining has proven to be very consistent, thus reducing the number of remakes and the chair side adjustment time.
The delivery time, under present circumstances, will actually be longer then it is for conventional restorations. However, what you will receive will fit better, require less chair time and will more likely be a bit less expensive, and in the long run a lot less expensive.
Conclusion
CAD/CAM dentistry is here and will only be growing. Dental technologists are embracing this because they can deliver a better restoration for the majority of situations and making themselves available for those delicate and difficult circumstances that the “scanners” cannot deal with. CAD/CAM is great but is unable to answer 100% of the dental restorative requests; your informed technologist can assist you with the choice of the best technology to meet your patients’ needs. oh
Andr Dagenais, RDT is currently the General Manager of Dental Services Group of Toronto and a District Manager for Dental Services Group / Sentage in the USA. He achieved his RDT status in 1974. He continued his development through training in Europe and the U. S. A. Over the years Andr has lectured to dentist and technologist groups throughout North America and has served on the board of the CDLC, DIAC and is currently serving on a committee of the CDTO. Andr also serves as an advisor to several professional and community groups.
Oral Health welcomes thi original arti
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The dental laboratory is about to change dramatically and you and your patients will be affected
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CAD/CAM technology is advancing daily and will assure a more consistent result in all restorations through the reduction of human errors
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Machining has proven to be very consistent, thus reducing the number of remakes and the chair side adjustment time
