Skeletal Hyperdivergent Treatment in The Permanent Dentition
Dr. Michel Champagne, BA, DMD, MAGD, IBO, CDE
As clinicians, we can make the decision to treat an hyperdivergent patients as young adults either as a regular patient that refused treatment at a younger age or as a new patient that just came in for a consultation. Hyperdivergency does not always come with an anterior open bite and a small anterior open bite could be acceptable in certain cases if a lip seal is present. The options have to be clearly explained to the patient.
If we encounter a patient with an inacceptable hyperdivergency, it may be of 2 types. One case may have a posterior cross bite and another may be almost normal in the transverse dimension. If a posterior cross bite is present, the situation is more complicated. The correction of the posterior cross bite may result in the exageration of the hyperdivergency. One approach to correct the situation is orthognatic surgery plus orthodontic and we will discuss it in another blog.
Without surgery, we still have some options:
-Option A : the extractions of permanent teeth combined with complex fixed mechanics to close the spaces toward the front of the arch, limiting bite opening. To even consider such an approach, the hyperdivergency must be relatively small (Figure 1).
-Option B : the intrusion of the posterior segments using mini-screws. We also may have to extract posterior cross bite or not. The posterior segments will have to be joined together either with a trans-palatal bar (TPB) or an acrylic splint with occlusal coverage. This occlusal coverage will temporarily increase the anterior open bite. Such a situation may be unacceptable to some patients. Another approach to be considered is Dr. Chris Chang approach (orthodontist from Taiwan). In his approach he uses a mini-screw placed in the infra zygomatic crest (IZC), away from the molar roots. The main arch wire can be attached directly to this mini-screws. This limits the temporary bite opening (Figure 2-3)
-Option C : still using the IZC approach, a clear splint (Invisalign or Spark) is a third option for molar intrusion and we will also discuss this option in another blog. This option may be better tolerated by adult patients.
Figure1. Case treated with bicuspid extractions.
Figure 2. Case treated with TPB and inter radicular mini-screws.
Figure 3. Case treated with acrylic splint and inter radicular mini-screws.