A look at new methods that combine the strengths of direct and indirect bonding
Orthodontic treatment is like any journey: The way it is started has a huge impact on the rest of the trip. Likewise, the results of the bonding appointment can influence the course of treatment for the doctor, the flow of the day for the staff, and the patient’s perception of the treatment. Any improvement, then, that can ensure consistency in placement accuracy, bonding success and appointment time should benefit everyone involved.
Historically, indirect bonding has been the technique employed to achieve those goals. Many orthodontists who tried this procedure, however, found it to be very technique-sensitive. Now, new technologies that are more readily available and affordable provide the means to experience the benefits of indirect bonding with fewer challenges.
Direct bonding poses its own challenges. The combined activity of moisture control, accurate bracket placement, proper adhesive bonding and complete flash cleaning can result in bond failures or necessary repositioning. However, by bringing together a number of relatively new innovations, it’s possible to realize the benefits of indirect bonding without mastering the many steps traditionally required. Put together, it isn’t simply direct bonding or indirect bonding; it’s a hybrid of the two.
The improvements in technology have created a new set of bonding options that allow for procedures to be done in fewer steps, improved assisting consistency, a shorter learning curve and a simpler bonding appointment:
Current software allows doctors not only to place brackets virtually but also to simulate treatment and make intricate measurements and adjustments. After precision bracket placement, a transfer tray can be printed quickly and affordably in-house using a 3D printer. The bonding appointment then becomes more straightforward: Load the brackets into the tray in advance, prepare the teeth, place the tray on the teeth, cure and remove.
The removal of excess adhesive, or “flash,” around the bracket has long been a source of frustration. In direct bonding, the flash must be removed without repositioning the bracket to avoid any residual adhesive on the teeth, and in indirect bonding, the last step is to grind away the cured adhesive once the tray is removed.
Another new technology now available is adhesive that’s been precoated onto brackets so there’s no flash to clean away. These remove the time and variability of adding adhesive to the base of brackets and cleaning flash away after placement. With these brackets loaded into the 3D-printed tray, the tray can be placed on prepared teeth and, after curing, removed with no flash to grind away. The process of using digital scanning, planning, printing and flash-free adhesive has been called “digital flash-free bonding.”
With these new elements, the start of the orthodontic journey is improved for everyone involved: Doctors have more tools than ever to do treatment planning with software; the team has a much more streamlined bonding protocol to follow with less variability; and the bonding appointment is shorter for the patient. And because the bond-failure rate of the flash-free adhesive is less than 2%, this process could result in fewer unscheduled visits for rebonding as well.
Essentials and benefits
Indirect bonding does rely on investment in technology and equipment. Fortunately, there are lots of options on the market that can meet a range of budgets, meaning you don’t have to start with the highest-end printer right out of the gate. A printer that uses DPL technology to print can be calibrated to produce a tray. Our practice acquired our first 3D printer more than three years ago, and now we have nine printers from four companies that range in price from $500–$24,000.
As with any change, employing a new technology will be an adjustment. For example, you may have to adjust your scheduling template, adopt a new workflow, experiment with tray design or refine printer settings. While it is an investment of both money and time, there’s sure to be a benefit of increased efficiency.
During the inevitable transition to the new process, it’s helpful to keep in mind the benefits that will result once established: Orthodontists will see an increase in precision and bond success rate; a decrease in labor required; shorter bonding appointments, meaning less chair time for the patients; and a cost-effective way to create trays. The practice will also see a shorter learning curve for their team and less need to mix or store impression materials.
With the advantages that come with using scanners, digital simulations, flash-free brackets and 3D printers, the bonding protocol is like building with Legos: All the pieces snap together with minimal effort. It’s standardized, but customizable. Practices will be re-energized by the excitement that digitally directed indirect bonding infuses into your practice. And your patients will be happy to see the implementation and success rate of state-of-the-art technology.
The advantages previously sought in the indirect bonding procedure can now be achieved with fewer steps and fewer components—and patients certainly don’t mind that there’s no uncomfortable impression-taking step!
1. Digital scan
To get the results you want, you must get the treatment started on the right foot. With a digital scan, orthodontists can quickly and efficiently get an accurate representation of the patient’s oral anatomy. Traditionally, impressions were time-consuming to get right and had to be redone because of imperfections. A digital scan alleviates a lot of the frustration orthodontists and patients alike experienced in this step.
2. Virtual bracket placement
For us, bracket placement on a 3D model is easily accomplished using a library of digital brackets within the 3Shape software we use. With this software, orthodontists can manipulate the model to test different scenarios and treatment options. This also ensures there won’t be unwanted rotation due to brackets not being completely expressed on the teeth at placement.
My preference in appliances are brackets by 3M Oral Care that utilize flash-free bracket technology. 3M supplies 3Shape with the bracket file, so we know it will be accurate.
Brackets placed on digital model
Printed tray with flash-free brackets inserted
3. Tray printing
The next step is printing the tray based on the scan from the first step using a 3D printer. At this point, you have two options: Print in-house or outsource the work to another company.
Designing tray and tray file ready for print
4. Bracket application
After the tray is printed, the flash-free brackets can be placed into the tray. Once they’re inserted into the tray, it is important to place the tray in a light-protected box—this is key to the success of the treatment, because the brackets will begin to cure if they’re exposed to light.
Loading a direct print indirect bonding tray with flash-free brackets
Finished tray loaded with flash-free brackets (occlusal view)
Light-curing the brackets through the indirect bonding tray
5. Tooth preparation
Now that the patient is in the office and the teeth are prepared for bonding, the tray will go on the teeth as normal and the brackets will be cured through the tray. After curing the brackets, the tray is easily removed and the patient is ready for wire placement.
With flash-free brackets, chair time is reduced because the cured adhesive flash won’t need to be cleaned after removing the tray.