Fixed Appliances, Palatal Expansion

Lower E-Arch (Arnold Expander)

Taken from “The Mandibular E-Arch” by Neal Kravitz, the E-arch is a fixed, spring-loaded expander for slow expansion of the maxillary or mandibular arches. Developed by Arnold, and popularized by Berkowitz, the E-arch was invented for maxillary orthopedic expansion in patients with cleft palates. In the mandible, the E-arch can create a modest amount (4 to 5 mm) of arch space in the lower anterior region by orthodontic tipping (rather than orthopedic change) of the lower posterior teeth, as well as distalization of the first molars. The appliance consists of a 0.040-inch tube-like frame with a NiTi open coil spring. Seating the E-arch compresses the open coil spring and activates expansion. Therefore, the E-arch is ideal where patient compliance or parent cooperation is a concern. The E- arch is typically banded to the first permanent molars; however, if these teeth have not fully erupted, bands can be placed on the second deciduous molars. In these situations, the clinician may consider placing lingual extension arms to prevent the second deciduous molars from expanding further than the first permanent molars.

Additional Options, Materials & Treatment Information

Treatment & Care

The E-arch is a pre-activated upon arrival and held closed with a ligature wire. After seating the appliance snip the ligature wire to initiate activation. The mandibular E-arch can be left active for approximately six months, depending on the amount of expansion needed. For patients requiring expansion in both arches, dentoalveolar decompensation with the mandibular E-arch establishes a “reference” mandibular arch width to guide the amount of maxillary expansion. Some patients have a tendency to try to flick the lingual frame with their tongue or pull on the appliance with their fingers. In these situations, consider bonding the lingual frame (not the coil spring) to a posterior tooth for added stability. While bonding the lingual frame will not affect symmetrical expansion, it may impede equal bilateral molar distalization.

Once you have achieved adequate mandibular expansion, you have the option of either removing the E-arch and delivering a lower Hawley or deactivating the coil spring and converting the appliance into a holding arch. The E-arch is deactivated by sectioning the coil spring intraorally using an FG #557 straight fissure crosscut carbide bur. For patient comfort, you may consider placing a small amount of flowable composite over the sectioned coil spring. The “passive” E-arch can be left on until the start of Phase II or the eruption of the second premolars.

This appliance should be cleaned every day with toothpaste and a soft toothbrush, morning and night. Encourage the patient to give sufficient time to clean thoroughly around the appliance, gums, teeth, and bands to maintain proper hygiene and prevent inflammation. 3 minutes is recommended.

Materials

Wire: American Orthodontics Chromium Cobalt
Screw: NiTi Spring

Additional Options

AO Maximum Retention Bands
Leone Web Bands
AO .022 Slot w/ Hook
AO Headgear and .022 Slot with Hook
AO MBT w/hook
AO Double Slot w/ Hook

More About Lower E-Arch (Arnold Expander)

Also Known As:

Arnold expander, E-arch lower expander

Who Made Me:

The E-Arch expander, first developed by Dr. Edward Angle in the early 20th century, has been modified over the years to include advancements like the Arnold Expander. This device allows for controlled lower arch expansion and is primarily used in cases of mandibular crowding or constriction. Modern versions feature more precise control mechanisms, improving overall outcomes.

The Dental is in the Details

We’re driven by hard-work and a relentless passion for dental excellence. It’s simple. ODL’s highly skilled lab technicians utilize the finest materials available to achieve ideal results for you and your patients. We stand by our craftsmanship and strive to exceed your expectations with every appliance.

Revolutionize the way you serve your patients with the Lower E-Arch (Arnold Expander)

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Lower E-Arch (Arnold Expander)