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I hate the term "Palatal Expansion." Can we please stop using it?

By: Brian J. Hockel, DDS


The term, "Palate Expansion" is often used both in orthodontics and in the world of airway care, but I hate the term.  OK, maybe "hate" is a strong word.  But I think it can be very misleading.  Let me explain.

Why do I really dislike the term “Palate Expansion”?

Because most expansion to which it refers is useless, inadequate, and/or at least a missed opportunity.

USELESS - "Palate expansion" is often a useless exercise in orthodontic mechanics that does not leave the patient with a problem having been solved.  I had triplet patients come to me for evaluation after having already had "palate expansion" in another office.  Only the upper arch was treated, and a minimal amount of expansion was achieved.  It was held for three months, and then all appliances were removed.  The plan at that point was to re-evaluate when the kids were older and had all their permanent teeth.  But they were already crowded by the time I saw them!  They were going to need more expansion in the future anyway.  So, for these three kids, the "palate expansion" was useless.  It didn't go far enough, and it didn't hold it long enough, and it didn't address the underlying causes.

INADEQUATE - Most "palate expansion" (by definition expanding the upper only; there's only a palate on the upper arch) is limited by the thinking that a crossbite (upper much narrower than the lower) must be present in order to make it worth it.  Or it's limited by not wanting to expand wider than the (usually also narrow) lower arch.  In both of these cases, the lower is not expanded at all and this severely limits the amount that the upper is able to be expanded.  So the amount of expansion is minimal.  It might be enough for the teeth to all come in, but in airway orthodontics we consider also the amount of space the tongue needs.  Correcting oral posture, which is addressing the root cause of bite and facial growth problems, cannot be done unless there's room for the tongue in the mouth.

Many orthodontists argue that "expanding the lower arch is not stable."  To which one should ask, "Oh, when you finish orthodontics, do you not give your patients retainers?"  In truth, there is no such thing as "stability" in the absolute sense as a guarantee that teeth won't move.  All patients must either correct their rest oral posture perfectly, or wear retainers.  The lower arch can most certainly be expanded, and the tongue and airway will benefit from the additional space this will gain.

MISSED OPPORTUNITY - Traditional thinking is that orthodontics is about teeth fitting together.  If you're going to have your child undergo treatment in the mixed dentition (baby teeth still present), there are good reasons to do so.  But expanding beyond the usual amount, aiming for 40-44mm between the upper permanent molars, will usually be better for the tongue space and growth potential.  Importantly, this will set the stage for myofunctional therapy to be more effective in correcting the rest oral posture: lips together, tongue to the palate, nasal breathing.


Another misconception is that the only kind of "real" expansion that is worth the effort is when the palatal suture is split open.  That happens with Rapid Palatal Expansion (RPE), and I have done that for many patients, including for my own daughter.  I have learned from John Mew that semi-rapid palate expansion can work in growing kids (and others!) and have the same effect without splitting open the suture.  The suture can grow and remodel and allow the palate to be larger by putting gentle forces on the suture to influence growth.

The argument is that any other expansion besides RPE is "just tipping teeth."  This is another sad misconception.  With good occlusal forces, and gentle expansion forces, bodily movement of teeth is possible even with removable appliances like Crozats and expanders.  Tipping of teeth does happen with minimal bone or with excessive forces, but it can generally be avoided.

I agree that many patients, especially non-growing teens and adults, can benefit most from skeletal expansion.  Skeletal expansion uses a MARPE (mini-implant assisted rapid palatal expansion), like the MSE (maxillary palatal expander) or a custom design, to open the suture and gain maximal bone movement with minimal teeth-tipping.  I use this approach regularly.  But it's not the only option for non-growers.

SO WHAT IF THE TEETH TIP??  Even with some tipping of the teeth, great benefit can be derived from increasing the intraoral volume for the sake of tongue space.  For many patients, tipping of teeth can actually be an acceptable compromise to allow improvement of airway and function.  The tongue doesn't care if the teeth are slightly tipped; it just wants room to function and posture in harmony.


Even when side-to-side expansion of both upper and lower arches proceeds with good and ambitious results, there's yet another concern I have: the front-to-back (anterior-posterior or AP) dimension of the intraoral space is mostly overlooked.  Some orthodontists and prosthodontists say, "It's all about the transverse."  Meaning that side-to-side expansion is the solution that matters.  As orthodontist William Hang has famously said, "You can't solve a front-to-back problem with a side-to-side solution."  Many patients have a need for the teeth and/or jaws to be further forward.  No amount of palate expansion (or upper and lower expansion) will address this aspect of the problem.  The problem is likely 3-dimensional, and so should the solution be 3-dimensional.


So to summarize, the goals of expansion are to get enough room for the teeth and the tongue, and to address a mandible being trapped backward.  Any approach that is most beneficial will aim for both the upper and the lower to be widened as much as possible, and for the AP dimension to be given equal or higher priority to the transverse dimension.  The root causes of the problem will also be addressed: the altered rest oral posture.  Otherwise, it might just be wasting time that could be better spent on more therapeutic solutions.  

Let's use the terms "transverse expansion" or "AP expansion,"  and let's do what they say.  I like "arch development" too.   I suppose if you're really going to do just "palate expansion," then go ahead, use the term, and show your limited thinking.


Limited thinking: 

Only expanding when a crossbite is present

Aiming only for tooth-space requirements 

Lower arch is not developed – “It won’t be stable”

Referring only to RPE or MARPE – “Aren’t you just tipping teeth”

Hold for 3-4 months and then “See you when you’re 12”

Overlooking underlying causes

Over-emphasis on the transverse and AP dimension is ignored

* All information subject to change. Images may contain models. Individual results are not guaranteed and may vary.