What is CAD/CAM dentistry?
The digital age of implant dentistry is upon us and CAD/CAM technology aids dentists in making a superior prosthesis for their patients. Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) uses computer software to design and manufacture the implant prosthesis. This digital form of dentistry is a world apart from the conventional method of taking impressions. Conventional elastomeric impression taking, by nature, is more prone to error due to the various steps and visits involved in the process, as well as the number of professionals that are required to complete a single restoration. The conventional method of taking impressions also is taxing on the patient, who must sit through multiple visits, poorly fitting trays being placed in the mouth with unpleasant textures and flavors from the impression materials (e.g. polyvinyl siloxanes, polyethers and hybrids), and potential lost time from work and multiple sessions of anaesthesia.
Digital impression taking, on the other hand, allows the dentist to take an intraoral scan of the patient’s mouth and create a customized implant based on the scan, with the final restoration having exceptional aesthetic, fit and longevity. This minimally invasive method also allows for the patient to pay only a single visit to the dentist and undergo a procedure that is far more comfortable, quick and painless than the conventional impression.
The 3 components of the CAD/CAM system
The CAD/CAM system is made up of three components: the digitalization tool / scanner, the processing software, and the milling device / production technology that creates the final product. The digitalization tool / scanner is responsible for taking the intraoral scan, which allows the dentist to digitally map out the topography of the patient’s intraoral environment. This scan is then processed by a software that creates a data output of the prosthetic design to be milled. The milling device / production technology makes up the computer-aided manufacturing element of CAD/CAM, and completes the entire process by creating the prosthesis based on the processed digital scan data.
Production concept options for CAD/CAM digital dentistry
Digital dentistry permits multiple avenues for creating a restoration with CAD/CAM technology. While most dentists capture the digital impression and send the data to a laboratory for milling, CAD/CAM also permits dentists equipped with the proper equipment and software to carry out the entire procedure chair-side in a single visit. Another less common alternative is that laboratories can use CAD/CAM in conjunction with pre-made physical impressions to create restorations.
Restorations in a single visit: CAD/CAM simplifies dentistry
The advantage of CAD/CAM as a chairside, single-visit treatment
Over the course of a single visit, a patient can sit down in the chair, have a digital impression taken, and walk out of their appointment with their new restoration already in place. CAD/CAM is a marvelous technology for this very reason, it allows the normally multi-visit treatment to create a dental restoration be minimized down to a single session, including full-mouth restorations. The advanced technology of chairside systems today allows for dentists to create maximum-precision 3D occlusal surface reconstructions within a matter of minutes using an intraoral scanner. Chairside systems are capable of veneers, crowns, inlays and onlays with a range of monochromatic or polychromatic materials including nanoceramics, high-strength ceramics and composite resins.
It is worth mentioning that the time saved with a single-visit restoration offers patients a list of some significant advantages. A single session means a single anesthetization, not having to take more time off of work, and not having to fuss with temporary restorations during the waiting period up to the final restoration.
Comparison of currently available chairside systems
There are several chairside systems currently available on the market. Cerec®, a product of Sirona® Dental Systems, was the original and first commercially available system, developed at the University of Zurich in 1980 and used to treat the first patient chairside in 1985. Cerec® was named for the acronym Chairside Economic Reconstruction of Esthetic Ceramic, and the system is currently on its third model, the 3D Cerec®. The Cerec® system uses a blue-colored light emission technique to take three occlusal scans to produce a digital image. This system has also been scientifically proven to result in minimal vertical misfit compared to some of its competitors.
E4D®, by E4D (formerly D4D) Technologies®, was released to the market in 2008, was the second commercially available system and is the second most widely used and technologically advanced chairside option. This system uses a red laser to take 9 intraoral scans for software processing. One disadvantage to the E4D® system is that it offers a much more limited amount of digital libraries compared to the Serec® system. Digital libraries, which essentially offer restoration design proposals based on geometry and morphology of adjacent teeth, can mean the difference between a good restoration and a perfect one.
The International Dental Show in 2017 was a groundbreaking event in terms of chairside CAD/CAM options, with five companies launching or presenting new CAD/CAM systems and introducing a handful of competition to the currently limited market. These new systems are: the CS 36000 by Carestream Dental, the DWIO & DWLM by Dental Wings, the myCrown Scan & myCrown Mill by Fona Dental, the PlanScan, Emerald and PlanMill by Planmeca, and the IntraScan & Inhouse5x wet & dry by Zfx. Many of the newer systems offer a big strides forward in the CAD/CAM system, with powder-free scanning and true-color display.
Disadvantages and limitations of CAD/CAM
While the groundbreaking technology of CAD/CAM offers numerous advantages, there are some significant setbacks. The initial investment of getting a digital restoration is much higher than that of a conventional restoration. There is also extensive training required for all members of the dental team who will be working with the CAD/CAM system, which is an investment of time and money for the dental office. Proper training ensures that a dental team is capable of laying out an appropriate scanning strategy and taking a high-quality intraoral scan, that together yield the highest quality restoration possible.
System compatibility was until recently something that needed to be taken into account, regarding open versus closed software architecture, as well as implant-specific scan bodies. Closed systems require that the laboratory carrying out the milling process for a restoration have the same manufacturer’s software as that which was used to perform the digital scans. Open systems, on the other hand, allow laboratories to use a variety of different softwares. Implant-specific scan bodies are required to be compatible with the specific software being used to perform the scan, but today there are many companies that produce compatible scan bodies, allowing for less-limited purchasing options for dental professionals.
The toolbox: What every dentist should have for CAD/CAM restoration
To determine the placement and orientation of the abutment and prosthesis on an implant system, scan bodies are used in conjunction with CAD/CAM technology to create a 3D digital image of the intraoral environment around the implant site. The scan body is made of a high-grade thermoplastic polymer called PEEK (polyetheretherketone), which is by nature a grey-opaque non-reflective material, allowing for optimal 3D digital image capture that overcomes the common issue of scattered reflection.
Also known as blank abutments, these single-piece abutments are mechanically manufactured (normally) titanium posts which are attached to the superior portion of the implant that protrudes through the gingiva, and is the part on which a restoration is fitted. Pre-milled abutments are the most common and least expensive type of abutment used, and being pre-fabricated makes them immediately ready for use and cost-effective. A variety of sizes, shapes and angulations provides options for a wide range of transgivial designs that are customizable to every patient. A scan body is used to determine the diameter, cuff height, interoclusal height and abutment angulation of the implant system to determine the appropriate design of the pre-milled abutment. Milling can be outsourced to a laboratory or done using the in-house CAD/CAM instruments in your dental office.
Ti-Bases are prefabricated two-piece abutments made of titanium, whose favorable combination of properties such as low specific weight, high strength to weight ratio, high modulus of elasticity, high corrosion resistance and excellent general biocompatibility make it an excellent material for dental implant superstructures and implants. Each Ti-Base is matched to the specific implant system, with options in collar height, angulation and rotation, based on the intraoral scans taken using a CAD/CAM system.
Multi-unit bar solutions
Dimensional deviation is a recurrent problem when it comes to milled overdenture bars. Even with CAD/CAM technology and its highly accurate digital scans, milled bars come back to the lab having deviation issues that result in misalignment of the implant components and subsequent lack of prosthesis stability. Edison Medical™ will soon be releasing an adjustable adapter for milled bar overdentures with an intrinsic mechanism that corrects dimensional inaccuracies, making dimensional deviation in overdenture bars a worry of the past. This multi-unit adapter will be a must-have for dentists that work frequently with patients requiring overdenture bars.
Closing remarks on CAD/CAM and digital dentistry
After a relatively slow development of CAD/CAM technologies through the late 20th century, the market is finally picking up speed and taking some impressive leaps forward. Not only is the return on investment for both patient and dentist potentially excellent, but with more professionals getting on board and transitioning into a more digital workspace, the technology improvements will only become more impressive and make those investments all the more worthwhile. With a handful of new competition on the market, competitors will surely be driven to outperform each other and continue to release more groundbreaking technology over the upcoming years at an elevated pace. Now is the time to educate and prepare you and your staff for a wave of game-changing technology that will revolutionize the dental industry.