Case Study: Hyrax-Halterman Appliance by Dr. Chris Teeters

Categories: Orthodontics;
Orthotown Magazine 

by Dr. Chris Teeters

Ectopic correction of first molar position is often complicated by a narrow maxillary arch. In cases like this, a few approaches are available to correct the ectopic position:
  • Using a segmental archwire from the primary second molar to the first permanent molar to distalize the molar, followed by the use of a traditional Hyrax expander. Challenges with this approach include the limitations of bonding a tube to the ectopic molar because of its position, and the crossbite can also interfere with the distal movement of the first molars.
  • Extracting the primary second molar and using a Pendex appliance to distalize the first molar. However, this often is only achievable after the leeway space is lost once the first molar has erupted more.
Neither option can achieve expansion and ectopic molar correction at the same time. Often, the primary second molar can be extracted to allow for eruption of the permanent first molar, but by the time the first molar erupts, there is significant loss of space that is difficult to regain.

This case demonstrates a novel approach to correcting both a posterior bilateral crossbite and bilateral ectopic first molars at the same time. We treated the patient with a Hyrax- Halterman appliance.

Diagnosis and treatment plan
An 8-year-old patient (Fig. 1) presented with a referral from her pediatric dentist because of concerns about her ectopic first molars and crossbite. A clinical examination revealed an obtuse nasolabial angle, a long lower facial height, near edge-to-edge overbite and overjet, insufficient incisal display on smiling, and severe maxillary and mandibular crowding.

The patient’s lower midline was deviated to the right, and she had a Class III tendency of growth given her retroclined lower incisors and mesial-step relationship of the primary second molars. Radiographic evidence (Fig. 2) suggested resorption of the distobuccal roots of the primary second molars with concomitant mesial drift of the first molars bilaterally.

Our objectives of treatment were to correct her posterior bilateral crossbite while simultaneously distalizing the first molars to regain space, with the hope to treat her with a non-extraction approach of the permanent teeth. This treatment plan called for a creative fusion of appliances: a Hyrax rapid maxillary expander with coiled Halterman arms soldered to the molar bands.
Case Study: Hyrax-Halterman Appliance
Fig. 1
Case Study: Hyrax-Halterman Appliance
Fig. 2

Sequence of treatment

Orthodontic bands, with the distogingival aspect reduced with a bur, were fit around the primary second molars and an impression was made. A Hyrax rapid maxillary expander was then soldered to the bands, along with the two Halterman distal extension arms on the orthodontic cast. Buttons were bonded to the occlusal surface of the permanent first molars with a twounit powerchain attached in advance.

The Hyrax-Halterman appliance was then seated on the upper primary second molars and the Halterman arms were ligated to the buttons. Composite buildups were placed on the lower permanent first molars to disarticulate the occlusion and allow for proper expansion. The patient turned the appliance once per day and returned for a follow-up appointment in four weeks (Fig. 3). At this point, the Halterman arms were bent back with a Weingart utility plier to continue the powerchain activation and distalization of the first molar.
Hyrax Halterman Appliance
Fig. 3

We instructed the patient to continue turning once a day, and at her second four-week visit (Fig. 4), the permanent first molars were completely unlocked from their ectopic position and the crossbite was resolved. We then removed the buttons and Halterman arms from the appliance and left the Hyrax component in her mouth for another six months to allow for bony fill (Fig. 5). The Hyrax was then removed and replaced with a Hawley retainer (Figs. 6–8).
Case Study: Hyrax-Halterman Appliance
Fig. 4
Case Study: Hyrax-Halterman Appliance
Fig. 5
Case Study: Hyrax-Halterman Appliance
Fig. 6
Case Study: Hyrax-Halterman Appliance
Fig. 7
Case Study: Hyrax-Halterman Appliance
Fig. 8

The Hyrax-Halterman appliance is a novel fusion of appliances to effectively and simultaneously correct posterior crossbites and ectopic molars. Since its inception in 2017, the Hyrax-Halterman has been used by hundreds of orthodontists worldwide. Having frequently used this appliance in practice, we have seen it effectively distalize first molars very successfully in every application. My colleagues have reported similar success as well. Additional studies are indicated to confirm its effectiveness.

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