Tech Tip: Troubleshooting engagers

While most of the time placing and removing engagers is a fairly simple process, it can sometimes be troublesome. We thought we’d offer up some of our “tricks of the trade” when it comes to troubleshooting the more common issues with engagers.

When engagers are not fitting in the aligner, aka “engagers are not tracking”

When an engager does not line up with the space created for it, it can cause discomfort or pain when inserting and removing the aligners. It can also delay the movements of the affected teeth.

In this situation you don’t want to force the aligner into place over the misaligned engager – this can do more harm than good by moving the tooth in unwanted ways.

Try the following options:

  • Remove the engager that's not fitting in the aligner, and use the previous aligner as a template to place a new engager on that same tooth.
  • Check for tight contacts that may be preventing movement and if you find any, follow instructions given for breaking tight contacts.
  • Inspect the engager for excessive bulk and/or flash. The excess material can cause the aligner to lift away from the tooth making the aligner less effective and may lead to tracking issues.
  • Try backtracking with the previous aligner, the teeth may just need more time to make the needed movement.
  • Though the engager will still apply pressure to the tooth and work towards completing that difficult movement, there may be a slight gap in the aligner because that tooth will be moving a little behind schedule. (In the meantime, Chewies may help close those gaps and help your patient feel more comfortable.)
  • If the aligner fits everywhere else, remove the engager that isn't fitting into the aligner and continue with treatment. That particular tooth probably will not move as scheduled on the treatment plan, but the movement can be completed later with a refinement at the end of treatment using auxiliaries or dimples.
  • If all else fails, remove the engagers from all of the teeth, take new upper and lower impressions, and request a case revision. This may delay treatment, but it will allow us to tweak the treatment plan for that particular tooth.

When engagers fall off

The most common cause for why an engager might fall off when removing the aligner, is that the composite is not fully adhering to the tooth. Bond failures are usually technique related and by doing each step well, the cumulative error in the chain of failure is reduced.

Common conditions related to engagers falling off (it could also be a combination of these issues):

  • Plaque might prevent the etch from working
  • The tooth could be a restoration (Try to avoid bonding engagers on restored teeth whenever possible. Advances in tooth-colored restorative materials have brought forward materials that do not etch, even with fluoric acid and are tremendously resistant to sand-blasting.)
  • Lubricant used on the engager template could have accidentally smeared on the tooth
  • Compressed air that is used to dry the tooth is contaminated with oil or water
  • Using too much primer
  • Excess moisture or saliva
  • Inadequate light curing (All light cure units wear down with time resulting in reduced curing intensity. Refer to your manufacturer's guidelines for proper care and maintenance to maintain performance.)

Try the following:

  • When plaque prevents the etch from working, using a pumice will remove the plaque properly.
  • If the tooth is a restoration, use a special etch for porcelain from your dental supplier. (Note: This does not always work.) Here is an article on bonding systems that may help you in choosing a bonding agent.
  • If lubricant from the template is accidentally smearing on the tooth, lift the template off of the tooth during insertion. Or, if possible, use the previous aligner to install the engager without using lubricant. The composite won't adhere to used aligners as much as it will to new templates.
  • Compressed air used to dry the tooth is contaminated with oil. This is the most common problem with compressed air and is hard to correct in the system.  Make sure to service and maintain your compressors to ensure clean, dry air. Try drying the tooth with a low-heat blow dryer that can be bought at a dental suppler. 
  • Using too much primer will weaken the bond between the engager and the tooth. Primers are meant to work in thin layers. A blast of compressed air for 3-5 seconds can help thin out the layer of primer. Refer to the manufacturer's guidelines before attempting this for the first time.
  • Intraoral retractors and saliva evacuation systems can help reduce excess moisture or saliva and will increase the integrity of your bonds.

Broken engager templates

Engager template can sometimes break due to a lack of lubricant in the engager void and surrounding area.

What to do?

If the engager template breaks, we’ll be happy to replace it. You may call and place the order with us, or fortunately, there is a quick and easy alternative that keeps your patient in active treatment.

Instead of waiting for a replacement template, you can use the current step as the engager template. Since it has been worn, the composite should easily release from the engager void.

Or, if you don’t have the current step, you can have your patient wear the new set of aligners without the engagers. Schedule your patient to come back for another appointment two weeks later, then use the worn-out aligners as an engager template for the next step.

We hope this tip helps you with any potential issues you might have with placing engagers. Check out our Help Center which is filled with useful information on the topic of clear aligner treatment.

If you missed any of our previous tech tips, we keep them regularly posted to our blog, which you can find here.

Until next time…

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