Aligners for Mild Cases

Orthodontic treatment for general dentists is largely delivered by aligners. The various aligner companies have different ways of grading the complexity of cases, and often have a product range to reflect this e.g. Align provide Invisaling Go, Go plus, and then other ranges within the comprehensive/full range.

So we can be lured into a false sense of security when patients are "accepted" for orthodontic treatment using these various product ranges. Whilst the criteria set by aligner companies may have been satisfied, this does not necessarily make the case "mild", or straightforward, and least of all easy! Below, we discuss a case which did appear straightforward, but for a few reasons became a little tricky.

This lady had a class II division 2 incisor relationship on a class I skeletal base, with a deep bite, crowding in both arches, and a gummy smile (although you cannot see it in the photos).

So what made this case difficult?

First, she insisted on having Invisalign, and that too with no attachments on the upper incisors! Second, she refused to have any extractions, so creating space wasn’t going to be straightforward. Third, her gummy smile meant that the gingival margins of the incisors at the end of treatment had to be perfect, and also meant I couldn’t let her teeth come too far forward to avoid the ”all teeth” look.

How did I manage it?

First, I agreed to start treatment without anterior attachments, warning her that treatment would not be effective and multiple refinements may be required. This was a mistake. Second, I created space by performing quite heavy IPR, 0.4-0.5mm all the way back to the distal of the lower 4s. Personally I feel this is quite heavy, the patient didn’t enjoy and nor did I. Third, I didn’t make a big deal about the gummy smile, and just built in some vertical over-correction to address the gingival margins (I could have done better with the UL3). I didn’t build in too much torque (inclination) correction of the upper incisors, again trying to avoid looking "all teeth" and knowing she would be having some post-ortho composite as well.

I also over-corrected some features, like the deep bite, incisor rotations and angulations. Knowing how and when to do this is essential to achieving a good outcome and a satisfied patient.

What could have been better?

Predictably, I struggled to align the upper incisors and she needed a lot of refinement. This time around, she was more than happy to have the attachments, so the aligners were able to deliver forces far more effectively. I simply would decline to do things this way again.

Creating space with IPR did work, but I really didn’t enjoy it. The alternative plan was to take out a lower incisor. You can see the final position of the lower teeth in either plan was extremely similar, and this approach makes my workflow a lot easier. Of course, I still give patients the option.

One of the key learning points for those of you starting out is understanding why it was important to create space for lower arch alignment, and not just resolve crowding through expansion and proclination. The approach is to ensure teeth remain within their alveolar housing as much as possible in order safeguard their periodontal status and reduce instability of your treatment outcome. It's fundamental to understand how to resolve crowding using the right method, in the right patient.

Orthodontic Learning Points

• Don't compromise on key treatment planning features.

• Resolve crowding using the right method in the right patient.

• Ensure you protect the teeth against periodontal problems.

• Put teeth in a position of stability to get a long term result.