Vince Tauro, MDT, CDT

The state of the dental laboratory industry always has been evolving, with some areas evolving faster than others depending on the needs and focus of labs, whether those needs be to increase productivity, quality or both. We have seen porcelain, impression materials, die-stone and other staples make dramatic advancements. But while these advancements enabled us to improve our product, our techniques largely remained the same. We waxed, invested, cast, completed temporaries, baked and stained porcelain the way it had been done for many years. 

Now we are witnessing a far more dramatic 

 in the laboratory industry with the restructuring of our traditional techniques since our industry has been introduced to CAD/CAM (Computer Assisted Design/Computer Assisted Manufacturing). Yet even as the technology gains hold and affects change on lab production, in the relatively short period of time it has been a part of the dental lab industry we have already seen numerous 

Before any milling or 3D printing can commence, a data set must be collected-via a scan of a model, impression or intraorally directly from the patient-and then interpreted to form the basis of the digital file that will be 

 to the CAM system for production. This information provides a starting point for what will be produced. Today most scanning takes place in labs with dental models serving as the starting point for the digital fabrication of a wide range of restorations. The focus here is the different technologies powering the scanners available to dental laboratories.

There are three kinds of scanners currently in use in the dental laboratory industry. These include touch-point, laser and structured- or stripe-light. Regardless of the technology being used, the task of any scanner is to reproduce an accurate digital representation of the physical work at hand. Some scanners do this better than others-for example, one scanner may take only two pictures while another may take 200 when tasked with scanning the same die. The difference in the actual amount of data collected by the scanner also impacts the way the software must “interpolate” or estimate the information required to fill in between scan points. The more accurate and complete the incoming data, the more accurate the digital model will be and the better the final manufactured result can be.

Depending on the complexity of the model, the scanner must be able to “read” all areas, including undercuts, so every detail of the model or impression being scanned can be accurately translated into the software. Any initial failings with the scan will be reproduced in the digital design of the restoration and likely result in a failed restoration. Every step in the 

 is important and related to either a successful or unsuccessful result. Some scanners rely on operator involvement to produce accurate results, and different operators can greatly influence the final result. For example, touch scanning’s accuracy depends on a correct contact angle between the die and the stylus. If two different operators scan the same die, the results may be different if each sets a different angle for the scanning stylus in relation to the die.

For touch-point scanners, a model is scanned by virtue of a stylus touching the model in various locations to record data. A die of a tooth is placed on a holder, which rotates with the scanner stylus in contact, through this spiraling process a series of data points are collected that are then evaluated to produce a digital copy of the die. Touch-point scanning is accurate and the scanners are often available at relatively low costs. However, the technology can be operator sensitive in terms of accuracy, the scanners can be limited in the size and type of models they can scan because of the required physical contact, and the scan times can be relatively slow. 

Laser beam scanners us a beam of light produced by a 

 as the basis for data capture. The beam originates from a fixed point and is combined with multiple cameras to record data. The cameras record the route of the laser beam projected on the object, taking digital pictures in concert with one another to produce a 3D image. The laser beam is used to orient scan data to reference points for the final image assembly. Laser beam scanning is accurate, has the potential to capture large amounts of data, can read undercuts and is uncomplicated for the person using the scanner. The disadvantages are that results are dependent on proper orientation of the model or impression being scanned, scan times are slower than structured light scans, and distortion can occur due to movement of the model being scanned.

Structured or stripe-light scanning-most commonly with white light-is the new kid on the block in the dental lab industry. The technology comes from the auto industry and other larger scale manufacturing businesses. Stripe-light scanners evaluate a model or a die that is placed in a fixed position. Shafts of light are projected in various bandwidths while the camera takes pictures. This method can record very accurate surface detail-with some scanners capturing more than 2 million points of reference from a single die. The captured data can include undercut areas that can be properly interpolated by the computer software assembling the digital model. These stripe-light scanners capture large amounts of data in relatively short periods of time, and are said to be extremely accurate. A disadvantage of light based scanning is the difficulty these scanners can experience when reading shiny surfaces.

As to the best scanner, instead of comparing the specific offerings from different companies, I’m going to focus on the qualities a CAD system needs to provide the greatest advantage to a dental lab. The ability to collect a substantial amount of data is a major plus. Another advantage comes from a system that limits the amount of operator involvement in the scan, which minimizes negative consequences because of operator error. It also is important to reduce the movement of the piece being scanned as much as possible, as movement reduces accuracy. Of course as with anything done in a dental lab, time is an important consideration. A high data capture rate with minimal scan time is best for those who use CAD/CAM on a regular basis.

In most complete CAD/CAM workflows, the trio of technologies consists of a scanner, software and a milling machine or printer. The interplay between these three technologies affects the quality and consistency of the work produced. The operator also plays a large role in the control of the process, but another constant in it all is the company that manufactures and sells these systems. This company needs to be able to detect and correct problems with the systems, as well as provide user training, support and make upgrades available when new technologies hit the industry.

In my time using a variety of scanners, I have become a proponent of white stripe-light scanning. I have used this type of scanner for several months and can report that the results have been outstanding. Fits and marginal integrity are exceptional, the software I am currently using is easy to maneuver through, while still allowing freedom in the type of restorations I can design, and it handles the complications that arise with some cases. And by no means least important, it is fast.

Vince Tauro, CDT, MDT, has more than 30 years of experience in all phases of dental technology and completed his certification as a Master Dental Technician at New York University. Vince has studied with many of the world’s leading ceramists and received further training at the Degussa and Ducera headquarters in Germany. He has lectured throughout the United States and many international cities. Vince is well known for his ability to make his work stand out through the creation of truly life-like restorations by applying creative layering and sculpturing techniques. He is currently consulting for Origin Precision Dental Solutions, a division of B&D Dental.

The D800 series scanners are said to feature advanced 3D scanning technologies and provide accurate scanning of gypsum models and impression models. Designed for medium to large labs, the scanners feature Texture Scanning capabilities for high detail detection and capture of hand-drawn design markings on the model; two 5.0 MP cameras; multi-die scanning for high productivity; fast scan times; and Dental System™ Premium software to cover the full range of dental indications.


	Vice President/Operations Manager
	Edmonds Dental Prosthetics Inc.
	Springfield, Mo.

We did a lot of research on the various scanners that were currently on the market. We looked at the longevity of the company, ease of use, the learning curve and customer support. The more we investigated it became clear that 

What do you like about using it in your lab?

Our waxers were quickly able to adapt to the new technology. We are able to work with our 3Shape distributor and 3Shape customer support for assistance whenever we upgrade our software. The scanners are true workhorses and we have had very few problems with them. Once you learn the software, upgrading and troubleshooting is very easy.

Would you recommend the scanner to other lab owners/technicians?

Yes. As with any new technology there is a learning curve and you need to be prepared to spend some time learning the system inside and out. The 3Shape scanners can become a very valuable tool in moving forward with digital technology.

The inEos Blue desktop 3D scanner is built on Sirona’s Bluecam technology that uses short-wavelength visible blue light to provide fast scan times and highly precise 3D digital models. An automatic capture function allows free movement of the model in any direction, providing complete control of the angle of the scan. Supplied with a dedicated computer and inLab 3D software, the scanner can be used as a standalone unit or in combination with the inLab MC XL milling unit for complete in-house production. In addition, inEos Blue can save and export scanning data in .STL format.


	Technical Director
	Professional Dental Lab Corp.
	Elkhart, Ind.

Why did you choose the Sirona inEos Blue scanner?

When it comes to scanners, there are many available in the current market to consider. We chose the inEos Blue from Sirona for speed, accuracy and consistency. With competitor “box” scanners the imaging is always the same and time consuming. With the inEos Blue, I can choose to capture as few or as many images as I feel is necessary for each case. The accuracy of the inEos Blue is second to none. With the launch of the inEos Blue, fit is no longer the topic of discussion.

In my lab everything is digitized. We no longer conventionally hand-wax anything. Digitizing with the inEos Blue has allowed me to do this quickly. I love that I can image a single unit of e.max CAD and have it milling in less than 5 minutes. There’s no other scanner on the market that can compete with that. If I didn’t have the Sirona system I would either have to send out or press in-house. But why not just mill everything? With the Sirona system, the inEos Blue is definitely the “Brains” of the operation.

In my opinion, every lab should have an inEos Blue coupled with an inLab MC XL and inLab Software 4.0. I have trained more than 150 labs in the past 4 years and can make it work in any lab (if the lab is willing). Based solely on speed, accuracy and ease of use, the inEos Blue is the best scanner on the market and I would highly recommend it to any of my peers within the industry.

Articles

Acquisition Center

	With the constant increase in the cost of gold, silver and the difficulties of working with non-precious and titanium alloys, the dental laboratory industry has been looking for alternative dental materials for many years. With the advent of digital scanning and advanced milling techniques, we have witnessed the growth of the zirconia restoration. Described by ceramic engineers as the “perfect dental material,” zirconia possesses great strength (Density of >6.0 g/cm, Vickers Hardness of 1,300 HV10, and compressive strength of 2,000 MPa); has the ability to be manufactured in the laboratory; when hand polished has the abrasion behavior similar to that of the natural tooth; and allows and intensifies the passage of light.

	Laboratories could achieve superior esthetic restorations with very strong sub-structures and over-laying compatible veneering porcelain. We have now taken the next step, the Monolithic Restoration.

	The definition of monolithic is a single crystalline component, formed from a single crystal. The monolithic Zenostar zirconia restorations are designed in full contour and are produced in the milling machine Zenotech T1 from the zirconia Zenotech Zr bridge translucent material.

	What separates the Wieland Zenostar restoration from similar restorations on the market is the level of translucency, the Zenotech Zr being the most translucent. For the natural coloring of the white zirconia material, a shading material Zenostar Color Zr has been developed by Wieland. The high translucency of the Zenostar material (Fig. A) in combination with an adjusted concept of shading  is responsible for a precise imitation of natural dentition.

	Wieland has developed a three zone shading concept using the brush method to color restorations. With the Zenostar coloring system (Fig. B) lively chromatic shades are achieved, and in addition, effect colors are available for individual effects. For further individualization, Wieland also offers stains that can be applied after glazing. To achieve proper shading, the Zenostar Monolithic restoration requires seven easy steps. An experienced user needs only 20 minutes of actual working time (design, nest, shade, stain and polish) to produce a finished restoration.

 Separate the work from the blank once the milling is completed (Fig. C).

 Connectors are removed with the instrument of your choice-the technician must be careful at this stage because unsintered zirconia is in a powdered form and is delicate. The cervical and body zones should be gently smoothed with a sandpaper point; it is highly advantageous to remove all scratches at this point. The occlusal surface can be individually characterized by using grinding tools (Fig. D). It is essential to avoid causing cracking, flaking, sharp edges, grooves or undersized areas.

 The cervical zone requires three circular passes with the brush, the brush should be dipped in the Zenostar Color Zr solution five times for each pass (Fig. E).

 For the body zone the solution is applied in two vertical passes, blending the solution toward the incisal. Here too, the brush is dipped into the solution five times for each pass.

 Effect shades are used to individualize the occlusal surface. Brown and or orange are recommended for central and secondary fissures; the effect white, ivory and gray violet for cusps and ridges. Finally, ivory or white can be applied to triangular ridges and cusp tips (Fig. F).

 Before sintering the restoration should be fully dried at 80°C.

 Polish restoration evenly with a bristle brush and a small amount of Zenostar Polish diamond paste. The occlusal surface must always be polished to a high shine (Fig. G).

	Alternative stain may be applied for further characterization and the restoration glazed using Zenostar spray glaze. It is recommended to lightly sandblast the restoration prior to glazing (Fig. H).

	A Wieland Zenostar full-contour monolithic restoration (Fig. I) is a highly esthetic, cost effective, biocompatible restoration with the abrasion behavior that compares to the abrasion of the natural tooth. You can create all-ceramic crowns and bridges with fully automatic design and manufacture. It is milled from innovative translucent Zirconia with high precision tools operating simultaneously in 5 axes. It can be individually brush shaded in 16 tooth shades to achieve better esthetics and quality than non-precious metals.

	There have been defined moments in the history of the dental laboratory industry. We’ve seen ceramics replace acrylics, refractory investments change the way we made laminates, Empress and pressables have redefined our need for alloy, CAD/CAM and Zirconia have created a new vision, and today we have full-contour monolithic Zirconia restorations. New technology is leading the way for laboratories to be competitive in today’s environment-we cannot run our labs with the same techniques we used yesterday. We must embrace this new technology. Wieland’s Zenostar Monolithic Restoration is that technology.

	Vince Tauro, CDT, MDT has more than 30 years of experience in all phases of dental technology and completed his certification as a Master Dental Technician at New York University. Vince has studied with many of the world’s leading ceramists and received further training at the Degussa and Ducera headquarters in Germany. He has lectured throughout the United States and many international cities. Vince is well known for his ability to make his work stand out through the creation of truly life-like restorations by applying creative layering and sculpturing techniques. Vince is the Manager of Technical Resources for DENTSPLY Prosthetics in their West Coast facility in Yucaipa, Calif.

 With the constant increase in the cost of gold, silver and the difficulties of working with non-precious and titanium alloys, the dental laboratory industry has been looking for alternative dental materials for many years. With the advent of digital scanning and advanced milling techniques, we have witnessed the growth of the zirconia restoration.