image-expansionMidLyne makes a wide variety of expansion appliances, each of which has a unique application.

We use only the finest wire and expansion screws. Instead of regular solder alloy, we employ brazing alloy and a brazing technique which dramatically increases the strength of metal connection.


An innovative approach to arch expansion, Oscars are 0.022 rectangular inconnel tubes soldered to the buccal aspect of the molar bands. Closed at the end to prevent a wire from penetrating the distal aspect of the tube, Oscars allow the practitioner to place brackets on incisors, and expand in the sagittal plane by putting an oversized archwire in the tubes. When tied into the brackets, Oscars work by utilizing NiTi coil springs, and expansion occurs via light, continuous forces. Elastic hooks provide added control of movement. When used in conjunction with an RPE expander, or lower “E” appliance, oscars are able to expand the arch bidimensionally.


RPE –The Rapid Palatal Expander is a common appliance for expansion in cases of maxillary constriction. MidLyne uses a SnapLock Ratcheting Screw to minimize turnbacks. A noticeable click reinforces to patients that activation has occurred.

Spring Activated RPESpring Activated- rpe

Spring activated RPE–This appliance employs an innovative NiTi Leaf system housed within the screw. The appliance is ligature tied with heavy brass wire. Simply clipping the wire will activate the expander.

Acrylic Bonded RPEacrylic

Acrylic Bonded RPE–This RPE utilizes vacuum formed acrylic. This achieves the effect of opening the bite to ensure activation without cuspal interference.

Quad Helixquad-helix

Quad Helix–Described originally by Herbst, this fixed appliance can be used in a wide variety of ways to expand or compress the palate. It is also used for molar rotation or intrusion. A removable variation is available upon request.


Haas Appliance–This expander incorporates palatal acrylic, providing the maximum palatal anchorage. This increased coverage allows for maximum orthodontic changes while minimizing crown tipping.

E Appliancee-app

E appliance–This fixed appliance consists of a rod and tube and an open coil NiTi spring. The spring produces light, continuous forces to expand the mandibular arch. A fixed lingual arch is frequently used following treatment with this appliance.


Frozat–A multi-functional device, the frozat can be used to expand or compress the lower arch. It is also used for incisor protrusion and even molar uprighting.

W Archwarch

W Arch–The W Arch, or Porter Appliance, is used for bilateral or unilateral widening of the palate. Simple adjustments are made during treatment to provide continuous activation.


Schwarz Appliance–This removable appliance consists of an expansion screw embedded in acrylic. A simple turn of the key will activate the appliance and contribute to lower arch expansion.