Industry Insights: No Separators, Perfect Fit — The Future of Banded Appliances

Categories: Orthodontics;
Industry Insights - No Separators, Perfect Fit: The Future of Banded Appliances 


Banded orthodontic appliances are experiencing a major evolutionary leap. Enabled by selective laser sintering technology, software-aided appliance design and the proliferation of intraoral scanning technology, 3D-printed metal bands and appliances will become a core offering in a short period of time. Because of its impact on part quality, clinical workflows and laboratory operations, laser sintering technology is poised to be the future of metal orthodontic appliances. Traditionally banded appliances are deeply woven into the fabric of orthodontic practice, and the fabrication of these appliances requires acceptance of otherwise unavoidable drawbacks.

"Band-supported appliances are many and varied, including space maintainers, habit mitigation and the like. While these appliances offer many advantages for our patients, the need to use bands to secure them poses challenges. Multiple appointments are typically required, a band inventory must be maintained and, when treating a mixed-dentition patient, management challenges can be added to the list. The advent of scanning technology has been a game-changer for younger patients; the most significant criterion for treatment in my practice used to be whether a child could tolerate an alginate impression. But even with scanning, creating adequate space and fitting bands was still a problem. Great Lakes sintered bands further simplify appliance fabrication, effectively expanding the ability to offer treatment by reducing chair time and the need for the patient to tolerate appointments and procedures."

— Dr. Cheryl DeWood,
orthodontics and dentofacial orthopedics practitioner, Glendale, Arizona

Traditional bands require separation, and thus some form of associated chair time and scheduling for the patient. This component of the banding workflow can be eliminated with laser sintering if a band does not require access to interproximal areas. A further challenge is introduced when a traditionally banded appliance is to be made in a laboratory, rather than in the office. Traditional bands interact with interproximal areas, but also regularly proceed subgingivally. Both requirements force a laboratory technician to modify areas of a stone model that are obscured to them. This creates potential error and leads to seating and fit issues.

One strategy employed to mitigate this issue is fixating already-fit bands into an impression. This method requires chair time to fit the band, and a high degree of accuracy and durability when fixating the bands in the impression. Even slight errors in fixation or disturbances during shipping will create difficulty with seating and fit. Another imperfect solution is to use scans to size bands. While this improves success when choosing a band size, it does not solve the primary issue facing technicians: concealed anatomy.

To directly address these concerns, a hypothetical appliance must require no separators, interact with only the anatomy that is visible in an impression or scan, and achieve a fit equal to a custom-fit band. Laser sintering can yield such an appliance.

Technological advances

Selective laser sintering (SLS) is not a new technology, but its application in orthodontic appliance manufacturing has become relevant very recently. SLS has seen applications in the crown, bridge and removable partial denture spaces for years, where it has been used to manufacture frameworks. The process uses a thin bed of cobalt-chrome (CoCr) powder spread over a metal build plate. Then, a laser selectively melts each layer of the intended device, fusing it to the previous layer, all in an inert atmosphere.

Once the parts have been grown, significant processing is required before they are ready for delivery. The parts remain attached to the build plate (Fig. 1) and are placed into a heat-treatment oven to relieve thermal stresses from the sintering process. After stress relief, the parts are separated from the build plate and support structures are removed. The bands and frameworks can then be smoothed and polished in preparation for assembly of the final appliance. Several smoothing steps are required, which can be performed either by hand or using isometric finishing.

Industry Insights - No Separators, Perfect Fit: The Future of Banded Appliances
Fig. 1

Laser sintering requires a large capital investment compared with traditional skilled fabrication, but despite this, laser sintering will become more common and accessible as the technology matures in dentistry.

The overall quality of an appliance with sintered components is superior to traditionally banded devices

To harness additive manufacturing, parts must be designed digitally. Design software allows experienced lab technicians to translate years of traditional bench experience into digital fabrication. Using a scan imparts a greater level of accuracy, but more importantly, it also allows the design of a custom band without the laborious process of a wax-up and casting. Technicians can adapt the shape of a band to visible tooth surfaces only (Fig. 2), which eliminates the most common sources of fit issues.

Industry Insights - No Separators, Perfect Fit: The Future of Banded Appliances
Fig. 2

Sintering can be wielded to fabricate entire space maintainers, bonded lingual retainers, expander frameworks and any other component requiring rigidity and strength (Fig. 3). Any components requiring precise placement in relation to tissue can be designed to stay low-profile while avoiding impingement. Additionally, any traditional components assembled onto a sintered framework are easily laser-welded, ensuring a strong connection.

Industry Insights - No Separators, Perfect Fit: The Future of Banded Appliances
Fig. 3

Laser-sintered appliances also improve clinical workflows.

When a band does not require access to interproximal areas, the separation step can be excluded. For many practices, this is a separate appointment, and for some there are separate appointments for both band fit and seating of the final appliance. Eliminating this step yields an immediate improvement in workflow and patient scheduling.

While removing separation appointments creates a predictable time benefit to all involved, there is also a marked improvement to chair time in the aggregate when considering appliance fit improvements. A band designed from scans which only engages visible anatomy creates a very streamlined bonding appointment with far greater consistency and less time lost to salvaging ill-fitting appliances.

The benefits of sintered metal appliances are clear for doctors and patients, but these also extend to the labs fabricating the devices. Competitive labs have adapted to advancing technologies, developing technical expertise in these areas and leveraging their experience with traditional appliances to create unique offerings.

Fabrication consistency is high and digital appliance records can be kept indefinitely for remake. Design parameters of appliances can be controlled more objectively, and in some cases quantified—creating better communication between labs and doctors. Highly technical elements are reallocated to the digital design portion of the workflow, providing opportunities for work to be done remotely.

As laser sintering technology becomes more accessible to labs, the main differentiating factor will be the quality of the digital design, anchored by the experience and skill of technicians.


Digital appliance design is the future of lab work, and laser sintering is the future of metal orthodontic appliances.

Leveraging new materials and fabrication techniques pushes the design and appliance effectiveness further forward and creates better diagnostic and therapeutic experiences for patients. Great Lakes Dental Technologies is committed to this pursuit and has woven it into the fabric of product development and appliance fabrication operations.


 

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Great Lakes Dental Technologies is an employee-owned company, with more than
200 employee-owners who design, develop, manufacture and market appliances and
products for use in the orthodontic, dental, and sleep and airway markets. Great Lakes,
one of North America’s largest orthodontic laboratories, offers more than 4,000 products
and services, and provides training and education on the latest technology, equipment
and appliance fabrication techniques. Information: greatlakesdentaltech.com




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