1 - The Jasper Jumper16,17 (Jaspar J., 1987) (American Orthodontics, 1714 Cambridge Avenue Sheboygan, WI 53082-1048, USA).
This was the first FFFA to appear (Fig.1a and 1b).
It is made up of a covered spring and is marketed in a kit of different sizes with both left and right sides. It is accompanied by a quite thorough instruction manual. It is also an appliance which is more comfortable for the patient because of its covering. Potential disadvantages are: the large inventory that must be kept, the coating material may degrade and fractures can occur with some frequency. The majority of articles published on FFFAs are about the Jasper Jumper. However, they are few in number, are comprised of mainly clinical cases, and rarely refer to the skeletal and dental changes seen in treatment groups or comparative studies.
2 - The Amoric Torsion Coils23 (Amoric M., 1994)
This appliance is made up of two springs, one of which slides inside the other (Fig.2). They are intermaxillary springs without covering and have a simplified application system of rings on the ends. These rings are fixed to the upper and lower arches with double ligatures.
They are marketed in one size only and are bilateral. A large stock of material is therefore, not necessary. The force exerted by the appliance is variable in accordance with the fixing points on the arch.
3 - The Adjustable Bite Corrector14 (Richard P. West, 1995) (Orthoplus, Inc., 1275 Fourth St., Suite 381, Santa Rosa, CA 95404)
This is an appliance which is assembled by the orthodontist as it is composed of various pieces - caps, closed coil springs, nickel titanium wire (Fig.3).
It can be used on either side of the mouth with a simple 180º rotation of the lower end cap to change its orientation. This reduces the inventory by as much as one half. In the center lumen of the spring we find a nickel titanium wire which is responsible for the "push" force generated. Repairs and replacements are rapid and easily carried out with this kit. The cost of repair is minor.
This is a coated intermaxillary torsion spring sold in a kit which includes the spring, the covering, the connectors, the ballpins and the glue (Figs.4a and 4b). There is no distinction between left and right.
The covering can be of different colors making it more attractive for patients. The orthodontist constructs the appliance, cutting the spring to the length seen fit. When a fracture occurs, it is only necessary to replace individual components. It has the drawback of being thick after the covering is applied.
5 - The Klapper Super Spring15 (Lewis Klapper, 1999) (Trademark of Orthodesign, 744 Falls Circle, Lake Forest, IL 60045).
This is a flexible spring element which is attached between the maxillary molar and the mandibular canine (Fig.5). The length of the element causes it to rest in the vestibule when activated. This facilitates hygiene and avoids oclusal surfaces.
The ends (fixing points) are different: The open helical loop of the spring is twisted like a J-hook onto the mandibular archwire. On the maxillary end it is attached to the standard headgear tube (Super Spring I) or to a special oval tube and secured with a stainless steel ligature (Super Spring II). This new version prevents any lateral movement of the spring in the vestibule. Only two prefabricated sizes are available (with left and right versions of each). The length of the spring can be increased or decreased by simply bending the attachment wires. The horizontal configuration of the attachment wire at the maxillary molar tube permits distalization with good radicular control.
6 - The Bite Fixer (Ormco 1717 West Collins Avenue, Orange, CA 92867)
This is a new intermaxillary spring coil. The spring is attached and crimped to the end fitting to prevent breakage between the spring and the end fitting. Polyurethane tubing is inside the spring to prevent it from becoming a food trap (Figs.6a and 6b).
The Bite Fixer is supplied in a kit with various sizes for both left and right.
7 - The Churro Jumper21 (Castañon R. et al., 1998)
This is an inexpensive alternative force system for the anteroposterior correction of Class II and Class III malocclusions (Fig.7).
The mesial and distal end of the jumper are circles. The distal circle is attached to the maxillary molars by a pin and the mesial end is placed over the mandibular archwire against the canine bracket. So far, this is the only flexible functional appliance which can be made up by the orthodontist in his lab. The costs are reduced and the time spent is minimal.