How to use clear aligner therapy to treat severe crowding [VIDEO]

Clear aligner therapy has been a growing option for patients who simply cannot tolerate or who deny fixed appliances.

The following case study was selected to demonstrate how with proper diagnosis, patient selection and treatment planning, clear aligner therapy such as ClearCorrect can acceptably resolve moderate to severe crowding with improvements in facial balance, dental function, smile esthetics and overall oral health.

Diagnosis and treatment planning

A 40-year-old female presented with the chief complaint that she didn’t like her smile and was seeking improvement in smile esthetics. The patient was symmetrical on frontal view and had a fat lip balance on profile view. The patient presented with normal gingival display on her smile as well as normal incisor display at rest for her age.

Step 1

A panoramic radiograph showed all permanent third molars were missing and a fair degree of restorations were present.

Root lengths were within normal limits. No clinical or radiographic pathologies were noted. The patient’s anterior dentition was shown to have moderate root tipping off of the axial plane. Cephalometric analysis all appeared to be within normal limits.

Step 2

The patient presented with Class I malocclusion, moderate to severe crowding: three-four millimeters of crowding in the upper arch and seven-10 millimeters of crowding in her lower arch. Her upper dental midline coincided with the mid-sagittal plane, and her lower dental midline was approximately four millimeters to her right.

This was to be expected, as the crowding was progressively more severe to the patient’s right with a lower right canine blocked out. The patient presented with thin anterior tissue, and with recession on her upper anteriors prior to beginning treatment.

Step 3

Fixed appliances were presented as a possible treatment option, as was clear aligner therapy. Proceeding with full braces was attempted; however the patient expressed concerns with the fixed appliances so we elected to complete treatment with clear aligner therapy instead.

Prior to proceeding with clear aligner therapy, the high degree of importance of patient compliance, which was necessary for treatment to work, was discussed. Considering the degree of crowding, patient compliance was fundamentally important to achieving the desired results.

Step 4

Due to significant crowding and the difficulty of having overlapping lower anteriors (which resembled progressive overlap like shingles on a roof) in the lower, the author elected to perform a series of interproximal reduction (IPR) PRIOR to taking PVS impressions to be sent to ClearCorrect.

When the PVS impressions were made for the ClearCorrect aligners, the patient was given a set of clear retainers to hold the position of the dentition after the IPR was performed. IPR was performed from the distal of the lower second premolar to second premolar, and on the upper, IPR was performed from the mesial of the canine to canine. Approximately 0.15 millimeters of IPR was performed per tooth surface.

Step 5

The patient’s upper arch took approximately 13 months and aligned predictably and uneventfully. The lower arch took slightly longer at 23 months, with one revision required at month 13. The patient was seen every six weeks. When debanded, judicious cosmetic enamelplasty on the incisal edges of the patient’s anterior dentition was performed. Clear retainers were made for the patient and the patient was instructed to wear the retainers only at night.

Step 6

The patient began with Class I molar and Class I canine malocclusion. The patient finished treatment in Class I molar and canine with acceptably resolved crowding. Midlines were improved, and root tipping was improved both clinically and radiographically.

Radiographic review showed no significant change in root length or shape upon completion of treatment. The anteriors were proclined and positioned in a more esthetically pleasing position both dentally and facially by providing natural lip support. The patient’s profile has shown improvement, going from a fatter lip balance to a more full convex lip balance, which is commonly viewed as a more youthful appearance.

Step 7

The patient stated she was extremely happy with the treatment and entire process. She was impressed with the results, and noted she never thought the outcome would have been as great as it turned out to be. The patient was very compliant and motivated, and said the care from and time spent with the treating doctor and associated staff was amazing; she felt the doctor did an excellent job of guiding her through the process.

Step 8

With adult patients presenting with moderate to severe crowding, it is important to diagnose clinically, with considerations of not just tooth alignment but also gnathological function, periodontal concerns and facial balance. With this patient, the treating doctor felt that any tooth extraction would have both facial compromises as well as functional compromises that would have been unacceptable for both the patient and treating doctor.

Non-extraction therapy was elected moving forward, and IPR was utilized to resolve the crowding, which maximized facial balance and improved dental function. As extractions have long been known to collapse the facial profile, and because the patient was in her mid-40s with an already fat profile to begin with, mild upper crowding and thin lips, the treating doctor felt strongly that a lower incisor extraction should only be considered as a last resort.

Additionally, since the patient’s pre-existing malocclusion presented with uneven, worn edges, it was felt that recontouring of the incisal edges would have a positive effect on the patient’s final cosmetic outcome.

This was accomplished by not removing any tooth mass on the deepest part of the worn tooth, and rather by reshaping the tooth as a whole into a more normal and esthetically-balanced dental smile arc. It should be noted that any type of tooth recontouring must be completed with great care.

Conclusion

Although some may argue that fixed appliances may have been able to finalize the desired dentition in more detail, both the patient and treating doctor felt that it was an inappropriate option for the patient, as she would not tolerate the fixed appliances.

The final results demonstrate that marked improvement in esthetics, function and overall patient well-being can be accomplished with clear aligner therapy such as ClearCorrect.