A Moving Target at 12: Weighing treatment timing in a growing Class III

Straight Talk draws its cases and discussions from the Orthotown message boards. Written by the editorial team with the assistance of AI, each article showcases how orthodontists tackle unusual and challenging scenarios.

A 12-year-old boy, within a month of turning 13, presented with a molar relationship that refused to be symmetric. Class III on the right, Class I on the left. The upper midline sat 2 mm to the right, the lower 2 mm to the left. Skeletally he was Class III, with a Wits appraisal of -10 mm against an ANB of 1.6 degrees, a spread wide enough that no single number captured the discrepancy. Crucially, the bite recorded was his centric relation. No anterior posturing, no slide, nothing to write off as a functional shift that would resolve once the patient stopped hiding an edge-to-edge contact. Facial and intraoral photographs, a panoramic film, and a traced lateral cephalogram documented the presentation (Figs. 1–4).

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The question posted to the board was specific. Extracting the lower right first premolar seemed like the way to address the midlines and the asymmetric molar relationship. But the treating orthodontist was not settled on it, and he was candid about why. He had initially worried the patient would keep growing Class III on the right side, which argued for caution about committing to anything asymmetric. Then he looked again at the midlines and noticed the upper one might actually be further off than the lower, which pointed the correction toward the opposite arch entirely. He also read the patient as maxillary retrusive to roughly the same degree that he was mandibular prognathic, a balance he took as reason to worry less about what growth would do to the profile. None of it resolved into a plan. What was he missing, and how would others treat it?

The first response came back with a question of its own. Any family history of Class III? From there he laid out a sequence that deliberately postpones the extraction decision rather than leading with it. Evaluate the skeletal transverse first, since an RPE may be indicated. Deprogram the occlusion with bite turbos. Advance the upper incisors with an advancement arch. In his approach, extractions come into view only after positive overjet has been established, and at that point four bicuspids may well be the answer. The warning was aimed squarely at unilateral extraction. Before committing to an asymmetric plan, he argued, the direction of growth has to be known, because otherwise the plan is aimed at a target that hasn’t stopped moving.

A second orthodontist took the midline observation at face value and used it to argue against the original plan. If the upper midline is the one that is off, then removing a lower right premolar corrects the wrong arch. He would leave that tooth where it is and, absent any change at a growth and development check, extract the upper left first premolar, the upper right second premolar, and both lower first premolars. Bite turbos to the lingual of the lower incisors, correct the anterior crossbite, then close the upper spaces while walking the midline to the left. It was the most fully specified plan anyone offered, and it still began with a wait.

That instinct hardened quickly into the dominant view. The extraction question, several argued, was premature in a way that no amount of careful planning could fix. A patient not yet 13 carrying a discrepancy of this size is one to monitor, not one to start. Full treatment in a Class III this pronounced risks unfavorable growth simply undoing the result, and the more committed the mechanics, the more there is to undo. One clinician was willing to go as far as limited alignment of the upper arch, but only if that was what the patient himself wanted out of treatment, with nothing further committed until the picture stabilized. Another would not begin full treatment for at least a year, making an exception only for a child facing genuine social difficulty, which is a real and separate consideration at that age.

How long to wait, and what would signal the moment, turned into its own argument. A six-month growth and development check was proposed and immediately challenged as far too short a window to reveal anything meaningful in a 12-year-old Class III. Serial cephalograms taken a year apart and superimposed were the counterproposal, on the grounds that only a comparison across that kind of interval reveals whether growth is still ongoing and which direction it is taking.

Then someone read the cervical vertebrae and concluded the patient had not yet entered his growth spurt, which meant the profile could still worsen, which argued for deferring treatment until growth had finished altogether. That reading drew an immediate challenge. Cervical vertebral maturation, the objection ran, is not accurate in Class III growth tendency cases. The clinician asked to weigh in went further and said its accuracy is low in general, and that he does not use it at all.

Which raises the obvious follow-up. If not that, then what does anyone use to gauge how much growth is left? One Townie described a working protocol of nine- to 12-month ceph comparisons paired with visual lateral and buccal checks, tracking where the teeth meet from year to year. When the ceph and the intraoral view both show no change, he tells parents the odds of the treatment failing or relapsing drop considerably, while making clear that it is not a guarantee. The clinician who had dismissed cervical staging works from a combination instead, weighing stature, degree of maturation, and genetics with family history, gender, phenotype, and which jaw is at fault carrying particular weight in a Class III.

He added one practical test worth keeping. Sometimes a slide is established firmly enough that chairside deprogramming will not budge it. In those cases, depending on the rest of the findings, getting the patient out of crossbite becomes a diagnostic maneuver in its own right rather than a treatment step, because what the bite does once released reveals something the records could not.

One orthodontist offered a look at what this pattern becomes once growth is no longer a variable, posting an adult with a comparable presentation. He ran a digital setup comparing removal of a bicuspid with removal of a lower incisor, and the lower-incisor version produced the better result. In his assessment, removing the bicuspid disrupted an otherwise sound occlusion, which is a meaningful trade-off for a patient whose posterior relationship is one of the few things working in his favor. Initial records and progress photographs taken several months into treatment show how the case was tracking (Figs. 5–8). The relevance to the adolescent was stated directly. A lower incisor extraction might be worth considering for him too, but only once he was done growing.

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The discussion kept circling back to the difference between a case that is difficult to plan and a case that is not yet ready to be planned. The question asked was which tooth to remove. The answer, more or less unanimously, was that the question cannot be answered responsibly yet, and that answering it early means a treatment plan built around a face that hasn’t stopped changing. Set against that is the patient sitting in the chair at 12, aware of how his teeth look, being told to come back in a year.

In a nearly 13-year-old with a Wits of -10 mm, an asymmetric molar relationship, and no dependable method for predicting when Class III growth will stop, do you extract into the asymmetry now and accept that growth may undo it, hold everything for a year of superimposed cephalograms and ask the family to sit on their hands, or treat the upper arch alone and leave the skeletal decision for a patient who is no longer a moving target? 

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