| Field | Value |
|---|---|
| ID | OA-0135 |
| Type | functional_appliance |
| Category | functional_appliance |
| Fixed/removable | removable |
| Primary function | skeletal jaw growth modification via muscle force redirection |
| Malocclusion target | Class II (FR-II); Class III (FR-III); also FR-I (Class II div 1) |
| Inventor | Rolf Fränkel, Zwickau, Germany |
| First year | 1966 |
| Period | historical / current |
| Status | current (less common than previously) |
| Uses TADs | no |
The Fränkel Functional Regulator is a tissue-borne removable functional appliance that works within the oral vestibule rather than on the teeth directly. Buccal shields (acrylic plates in the buccal vestibule) remove the restrictive pressure of the cheeks and lips from the alveolar processes, while wire components (labial bows, palatal arches) guide jaw posture. The FR-II addresses Class II, division 1 (mandibular retrusion); the FR-III addresses Class III with maxillary deficiency. The FR-III's acrylic pelotas (pads in the upper vestibule) stimulate sagittal maxillary growth. Treatment is typically 2–3 years and requires full-time wear.
By positioning buccal shields away from the alveolar bone, the Fränkel eliminates the restrictive lateral pressure of the cheeks, allowing transverse arch development. The posturing induced by the appliance redirects muscle forces to stimulate growth in the desired direction (mandibular forward for FR-II; maxillary forward for FR-III). The appliance is primarily tissue-borne — minimal occlusal contact — making it distinct from tooth-borne functional appliances (Twin Block, Bionator). The FR-II holds the mandible forward (Class II correction); the FR-III holds the mandible back while protruding the upper lip (Class III / maxillary advancement).
FR-II: Class II, division 1 in growing patients with mandibular retrognathia; FR-III: Class III in growing patients with maxillary deficiency; early treatment (6–10 years) where growth modification is the goal; practices specializing in functional orthodontics; adjunct to later fixed appliance therapy.
Long treatment duration (2–3 years) and full-time compliance required; technically complex fabrication requires experienced lab; limited evidence of superiority over other functional appliances; results are dependent on growth potential; less commonly used today than Twin Block or Herbst.
Frankel appliance fabrication is technically complex — requires precise impression technique (capturing vestibular depth), construction bite registration, and careful lab work to position shields correctly in the vestibule. Specialized lab experience is required. CFL can reference experienced functional appliance labs for Frankel fabrication.
lower lip pads
Frankel type
upper vestibule
configuration
produced by some labs for shorter treatment periods
Grokipedia](https://grokipedia.com/page/Frankel_appliance)
Society](https://bos.org.uk/museum-and-archive/appliances-and-equipment/functional-appliances/frankel-function-regulator/)
AJODO](https://www.ajodo.org/article/0002-9416\(85)90068-5/fulltext)
shields, FR-II vs FR-III design, fabrication complexity, Fränkel 1966 origin.