Short Lower Jaw (Class II) Correction
Class II refers to an anteroposterior (AP) jaw discrepancy due to over development of the top jaw/protrusion of the upper teeth, from a small lower jaw, or combination of both. A patient who presents with this discrepancy has the apparent look of having a weak lower jaw and chin. Listed in this section are examples of some treatment modalities Moshiri Orthodontics regularly uses to treat Class II malocclusions:
Functional Appliances – The Twin Block and M.A.R.A.
These orthopedic appliances are used to modify underlying skeletal discrepancies due to inadequate or excessive skeletal growth. The examples in this section and below are for patients that exhibit inadequate length, or deficiency, of their lower jaw. The appliances are worn for about the period of a year to achieve the desired result.
The Twin Block is a removable functional appliance comprised of upper and lower retainers which work in concert to correct a Class II malocclusion (lower jaw behind upper jaw) for adolescent patients. Often, the upper appliance also has an expansion component that requires activation as many Class II patients also have a narrow maxilla. At scheduled appointments, Drs. Moshiri may add acrylic to the lower retainer to further “push” the lower jaw forward as patients adjust to their corrected positions. For more information on the Twin Block appliance, read our informative Twin Block handout.
The M.A.R.A., or mandibular anterior repositioning appliance, is a functional appliance which creates positional changes of the lower jaw, positioning it forward over the period of a year while at the same time expanding the upper jaw to “fit” to new position of the lower jaw. This change in position favors correction of a Class II skeletal malocclusion, or “weak” lower jaw. In many adolescents, this appliance is able to improve their profile significantly; however, for few patients, full correction may involve orthognathic jaw surgery later in life. For more information on the MARA appliance, read our informative MARA handout.
Distalizers work by moving the upper teeth posteriorly to create space in order to alleviate crowding, and in to allow for better interdigitation of the upper and lower teeth when the upper teeth have migrated anteriorly over time.
The Carrière distalizing appliance is a fixed appliance (non-removable) that is used for dental correction of anteroposterior problems in the dentition. This appliance is used in Class II dental malocclusions (upper teeth ahead of the lower teeth), prior to braces or Invisalign treatment, in order to help alleviate the horizontal discrepancy of the upper and lower dental relationships. For more on the Carrière Distalizer, download our Carrière handout.
Class II Dental Correctors
This type of appliance works in a similar manner to orthodontic rubber bands; however, the appliance is not removable. It is used to achieve front to back movement of the teeth in order move the lower teeth forward, and the upper teeth backward so the bite fits together properly. Below is one example of one such appliance.
The Forsus appliance
The Forsus appliance is a fixed appliance that is used for dental correction of anteroposterior problems in the dentition. The Forsus is used in Class II dentitions (lower teeth behind the upper) when elastic force alone is not enough to fix the discrepancy, or when a patient has not been compliant with their elastic wear. Download our Forsus Appliance handout for more information.