Strategy Milling combines old and new for precision dental restorations

Much has changed in the dental and medical industries in recent years, particularly as digital technologies advance. Newer, however, isn’t always better. While Strategy Milling, a manufacturer of dental restorations based in Leetsdale, Pennsylvania, has fully embraced automation and digital technology, the company swears by the oldest of materials for restorations: gold and other precious metals.

Strategy Milling creates direct-milled crowns and bridges in gold, palladium, cobalt-chrome, and titanium alloys. Gold, in particular, is the gold standard in dentistry, says Scott Mappin, president and CEO of Strategy Milling. Materials such as zirconia are gaining popularity due to lower cost; however, the superhard zirconia wears down anything it comes into regular contact with, namely other teeth. Gold doesn’t, and added to its other advantages such as biocompatibility and malleability, it’s virtually unbeatable for restorations.

Gold’s drawback is its high price, but Strategy Milling came up with a solution – producing its own gold and other alloys in house using a proprietary manufacturing process, making it the first North American company to manufacture precious metal disks for milling, according to Mappin. The company manufactures relatively porosity-free metal pucks and monitors, maintains, and tests them using laser and inductively coupled spectrograph technology.

The thorough testing ensures no foreign material contaminates the alloys and that they maintain elemental stability and quality. Strategy Milling conforms to regulatory requirements for traceability and can track any of its restorations back to their elemental makeup.

The company then uses its supply of pucks to mill crowns and bridges based on digital files emailed by dental laboratories. The files are sent to CAM, and the element is nested into the appropriate place in the puck and sent to the mill. Nesting one part takes about one minute. Milling time varies depending on the part, but a single gold crown takes about 15 minutes to cut.

Advantages of milling

Mappin is passionate about the advantages of milling compared to casting or 3D printing.

“Casting has many issues,” he says. “Molten metal shrinks when it cools. In parts with many varied thicknesses to the final shape, controlling the shrinkage is a problem. This shrinkage leads to porosities and tears in the metal structure and can affect grain structure consistency. With milling, a blank is manufactured using processes that minimize these issues; then, a precision mill cuts the part from that blank. This altered manufacturing process leads to a better product as the issues created in cast parts with many thicknesses across varied shapes are eliminated. Also, the part can be designed according to the finished specs rather than enlarged. Castings have a skin that needs to be removed to get to polished metal. In our manufacturing, we produce parts that take a minimal amount of time to polish and don’t require the removal of as much alloy to achieve the finished state, speeding up processing time.”

With metal 3D printing, meanwhile, there are limits on the length of a span that can be produced before it starts to warp. In addition, the powdered metal material plus the coating on the particulates together create carbon, which can mean future problems in restorations. The technology also doesn’t match the accuracy of milling, leading to ill-fitting crowns, which can cause complications such as pain and infection.

It’s all about longevity, Mappin says. Strategy Milling prides itself on getting restorations right the first time, so they never have to be redone or replaced. In its 11 years, the company’s external remake rate has remained less than 0.5%. This is at least partially thanks to its advanced mills. Strategy has seven mills on the premises, and four additional mills are expected to be placed soon. The models are Roeders RXD5 and RXD5C, and Roeders RCS-1 automation robots and magazines have been added to each mill for automated, lights-out operation for up to 72 hours. This allows the company to keep head count low and provide faster turnaround time for customers.

The machines can also mill prosthetics directly to the implant interface, eliminating the need for abutments. Currently, Strategy can mill multi-unit prosthetics that fit nine different implant companies’ interfaces. It’s also developing capabilities for single-unit, engaging, patient-specific gold and porcelain-fused-to-metal (PFM) implant crowns and substructures.

Embracing digitization

Mappin is a big fan of digital technology and its capability for accuracy and efficiency, as well as increased material options.

“These developments provide more consistent production by eliminating many variables from human-to-human handwork,” he says.

Digitization also makes the future bright for companies such as Strategy Milling as traditional knowledge fades from the workforce. Fewer people are learning to cast metal, instead outsourcing prosthetics to be milled or printed.

“You don’t need to know how to cast or work with metal anymore to get a fine restoration made of metal back, because we’re here and we can fill that void,” Mappin adds.

With the increase in digitization also comes an increase in so-called chairside manufacturing, about which Mappin has mixed feelings. The upside to dentists being able to create restorations in the office is patients will have increased service options. The downside is these restorations are likely being made by someone who hasn’t been to school for dental technology – a separate industry from dentistry. This may lead to subpar restorations and highlights the continued need for dental labs with trained technicians.

Overall, digitization and technology are changing the medical and dental industries for the better, Mappin believes – and quickly.

“As software and hardware advance and processors get stronger and more detail can be managed more easily and you can work under microscopes, I think it’s all going to change the world in a great way and exponentially fast,” he says.

He’s impressed by the precision he’s seen in the latest robotics technology, whether it’s used for rocket components or surgical procedures. He has been in the dental technology industry for 45 years and has watched it evolve from analog to digital production, and has been at the forefront of advances in digitization and automation. Now, as he eyes retirement in the next few years, his goal is to set Strategy Milling on a path of continued growth and success.

The technicians who operate the puck-manufacturing machinery are highly trained in the company’s unique process. In this regard, robots will never replace the human workers who understand and are skilled in the technology. Most industries are still trying to figure out how humans and robots can coexist in the workforce. This continues to be a challenge as artificial intelligence (AI) advances so rapidly, and much is uncertain about the future. As Strategy Milling has shown, however, while automation is a remarkable development for precision and efficiency, there are areas that still require human eyes and minds.

A human touch is especially invaluable in healthcare, keeping it from becoming what Mappin refers to as “health commerce.” He believes patients deserve the best, whether from doctors or medical device manufacturers. Strategy Milling has invested a great deal of time and effort into bringing the best out of its employees and machinery. The company is a good example of what the future of healthcare may look like. With people and machines working together, the potential for top- tier care is greater than ever before.

About the author: Clare Scott is associate editor for Today’s Medical Developments magazine. She can be reached at CScott@gie.net or 216.393.0314.