The Schwarz removable expander provides mid-line expansion to widen the arch, The removable Schwarz expander is fabricated on upper or lower arch. Typical wire frame configuration is cuspid to cuspid labial bow, Adams clasps on first molars & a second set of ball or arrow clasps at premolars

Similar to the standard schwarz but utilizes a hinged screw to widen the anterior while maintaining molar width.

Essentially a Schwarz without labial bow (pictured here with buccal tube clasps). Retention is usually 2 pair of Adams clasps at first molar & 1st bicuspid similar to sagittal appliance.

Sagittal appliances regain lost arch length in an anterior and/or posterior direction. Usually fabricated without labial bow and Adams clasps on the first bicuspids and first molars.  Maxillary sagittals position twin expansion screws at the mesial of the first molar, the appliance is cut into 3 sections to allow for expansion.  The mandibular appliance positions the screws in the cuspid/bicuspid area.   Springs may also be incorporated to move the canines into position as space becomes available.  Also acrylic coverage on the posterior teeth may be incorporated to relieve maxillary / mandibular occlusal contact during treatment.

A third mid-line screw may be added to the sagittal expander if transverse expansion is desired.

3-way expansion, but in a different manner than the sagittal. The Bertoni screw is independently activated in 3 directions. Anterior is moved forward & each side is widened independently of each other. Wire framework is same as Schwarz, being cuspid to cuspid labial bow, Adams clasps on first molars & ball or arrow clasps at bicuspids or premolars.