Managing Missing U2s With Clear Aligners by Dr. Jonathan Nicozisis

Unconverging converging roots using the “AMP technique”

by Dr. Jonathan Nicozisis

Managing missing U2s (upper laterals) is a challenge on many levels. Concern for cosmetics is a foremost worry, with potential breakage of a crafted pontic as a close second. When thinking about using aligners for such cases, the logistics of managing a pontic with a removable orthodontic aligner appliance can make one’s head hurt.

Historically, approaches and techniques for clear aligner patients have involved tooth-colored paint or PVS material to be placed in each aligner. These procedures are labor-intensive for the doctor or staff, and color match is technique-sensitive because mixing stock colors to match a patient’s tooth shade can yield inconsistent results. Current paint options are often opaque and irreversible once placed. PVS material is porous and eventually stains. Tooth-colored wax is practical, but still the patient must be edentulous when removing aligners to eat or drink.

As orthodontists, we often feel responsible for providing a cosmetic, good-performing solution. We feel tremendous guilt when size, shape and color is less than ideal, and often have uncomfortable conversations with patients and parents who aren’t pleased with our attempts.

We have to ask: Are orthodontists really able to provide the best cosmetic solution for patients who are missing U2s but want to use clear aligners for their treatment? I think the honest answer is that we are not.

After years of trials, tribulations and titration, I would like to introduce a protocol I have been successfully using to best manage missing U2s with aligners. I have named this the AMP technique, which is an acronym for “Ain’t My Problem.” (When you say the phrase out loud, you can feel immediate relief as the burden and guilt rolls off your shoulders.)

The AMP technique is all about delegation to the patient and the restorative dentist or prosthodontist, and has practical and biomechanical advantages that are superlative to historical approaches. Here, I’ll review a few clinical presentations and the AMP technique solutions that were incorporated into each treatment.


Case 1 (Figs. 1–4): Existing bridge
When a patient presents with an existing Maryland bridge, refer them back to the dentist to section off one abutment, leaving a cantilever pontic. In addition, instruct the dentist to reduce the proximal surface of the pontic, leaving 0.5–1 mm space between the pontic and the tooth that was the previous abutment, because it “ain’t my problem!”

AMP Pearl #1: When designing the digital treatment plan, have the cantilever pontic and abutment move as a single unit.

AMP Pearl #2: Maintain space between the pontic and the adjacent tooth.

AMP Pearl #3: Extend the aligner only halfway up the buccal and lingual of the pontic crown, to minimize any forces upon insertion and removal of the aligner and help mitigate bond failure of the pontic.

Fig. 1: Initial.

Fig. 2: Final 8.5 months, aligners in. Note aligner is trimmed buccal and lingual to the pontic.

Fig. 3: Final 8.5 months, aligners out.

Fig. 4: Final restorations, implant #7 and crown #10.

Case 2 (Figs. 5–16): Opening a previously closed space for a missing U2
Give the patient tooth-colored wax to place in each aligner because it “ain’t my problem.” This is advantageous because the space of the missing laterals is constantly changing and increasing, which makes it impossible to use an acrylic pontic that would be transferred from one aligner to another. It also negates the labor-intensive painting a pontic in each aligner that would be time-consuming for staff or doctor.

AMP Pearl #4: After pontic space is created and will no longer be changing, refer to restorative dentist to create a cantilever pontic before scanning for additional aligners. Ask for there to be 1 mm space between the pontic and adjacent tooth and if there is any remaining second order root tip of the abutment necessary, make the pontic 1.5 mm off the gingiva so it is shorter vertically. This will allow space for the pontic to move into the gingiva during the second-order movement, creating an ovate pontic.

AMP Pearl #5: Assess which tooth adjacent to the space needs more second-order root movement and make that tooth the abutment tooth because of the biomechanical advantage of the extended lever arm created by the incisal edge of the pontic. This biomechanical advantage is why managing missing U2s is even better than the real thing. You can’t do that with braces!

Fig. 5: Initial.

Fig. 6: 18 months progress, TAD-assisted expander aligners and Class 2 elastics.

Fig. 7: 18 months progress; UR1 needs mesial root tip.

Fig. 8

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Figs. 10–16: Final 24 months.

Fig. 10

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Case 3 (Figs. 17–21): Patient presents with bilateral bonded bridges
Send back to the dentist to section them because it “ain’t my problem!”

Fig. 17: Initial.

Figs. 18–21: 16 months of treatment.

Fig. 18

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Fig. 21