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facebow In conjunction with extraoral traction anchored on the back of the head or neck, a long metal bow which inserts intraorally into an orthodontic appliance. Generally used to move teeth or bones posteriorly or prevent their forward movement.

facemask The component of a (primarily) extraoral, reverse-pull or protraction appliance that distributes responsive force across much of the face.

facial Of or relating to the face. Often used to identify the surface of a tooth located nearest the face.

facial asymmetry A term used in the negative sense to describe a reduction of similarity or proportion between the right and left sides of the face or the craniofacial skeleton. May also be applied to any structure that is too large or small so as to be out of balance or not proportional to other structures.

facial concavity A term applied to the analysis of a profile. The shape is described as an inwardly rounded curve from the forehead to the lips to the chin. A concave facial profile is often associated with a Class III malocclusion.

facial convexity A term similar to facial concavity, but describes an outwardly rounded curve from the forehead to the lips to the chin. Facial convexity indicates a fullness in the lip region and is associated with a Class II malocclusion.

facial esthetics A term pertaining to facial beauty, symmetry, balance and proportion.

facial form The configuration, shape or appearance of the face from an anterior frontal view.

facial growth The process of enlargement of the craniofacial skeleton and soft tissues.

facial pattern A term generally used to describe the facial form or the direction and type of facial growth.

facial proportions An assessment of the balance of the face from a frontal or profile view. The intent of the assessment is to determine asymmetry or imbalance.

facial type A classification of the face. Three facial types are described: brachycephalic or euryprosopic (wide, short), dolichocephalic or leptoprosopic (long, narrow), and mesocephalic or mesoprosopic (average).

faciolingual The local direction perpendicular to the mesiodistal direction and parallel to the occlusal plane; the facial direction/sense is away from and the lingual (or palatal) direction/sense is toward the tongue; labial and facial are synonymous in the anterior portion of the dental arch, and buccal is synonymous with facial in the posterior portions of the dental arch.

fee for service dentistry A method of paying practitioners on a service-by-service basis rather than a salaried or capitated basis.

fenestration A window defect of the gingival tissue or alveolar bone contiguous to the root surface.

fiberotomy A surgical procedure designed to sever the gingival and/or transseptal periodontal fibers around a tooth usually to reduce the tendency for relapse of corrected tooth rotations.

finger spring A configured segment of wire that may be included in an orthodontic appliance or a retainer to, when activated, tip a tooth in a desired direction.

finishing A stage of treatment toward the end of comprehensive orthodontic care in which the teeth are placed in their final detailed position.

first-order Pertaining to rotational or vertical tooth movement or displacement potentially visible in an occlusal view.

first order bends  See bends, first order.

first order rotation A tooth as a whole rotates about an occlusogingival axis. The angulation/orientation of the long axis of the tooth does not change.

fixation Immobilization of the facial bones after a surgical procedure by means of wires, screws, plates, elastics, or splints until the healing process is complete.

fixed appliance An orthodontic appliance whose attachments are bonded or cemented to the teeth and cannot be removed by the patient. Generally termed 'braces' by the lay public.

flush terminal plane A developmental stage. The normal and desirable time-linked relationship of the distal surfaces of the upper and lower second primary molars.

FMA Cephalometric assessment of the inclination of the lower border of the mandible to the Frankfort plane.

FMIA Common cephalometric assessment of the lower incisor inclination.

force A mechanical action of one body on another that tends to displace and/or deform the body receiving it. Force may be continuous, intermittent, interrupted, intraoral, extraoral, orthodontic, orthopedic, elastic, spring, magnetic, etc. depending on the motivating elements involved.

fossa,glenoid See glenoid fossa.

franchise dentistry A system for marketing a dental practice, usually under a trade name where permitted by state laws, in return for a financial investment or other consideration. Participating dentists may also receive the benefits of media advertising, a national referral system and financial and management consultation.

Fränkel appliance An activator type functionalappliance intended to stimulate or inhibit jaw growth, retrain muscles or widen the dental arches.

free-way space The clearance or interocclusal distance between the upper and lower teeth when the mandible is in the postural resting position.

frenectomy The surgical removal or repositioning of a frenum. Performed to enhance the stability of a corrected diastema or to alleviate a tongue-tie.

frenum A fold of mucous membrane and underlying fibrous tissue connecting lip, cheek or tongue to the alveolar mucosa. (May be labial or lingual.)

friction A resistance to the relative displacement of contacting bodies in a direction tangent to the plane of contact.

frontal cephalometric radiograph A radiograph taken with the x-ray source located behind the head and the x-ray film located in front of the face taken according to cephalometric conventions. More correctly termed a posters-anterior (P-A) cephalometric radiograph.  See cephalometric radiograph.

full treatment Comprehensive orthodontic treatment including both upper and lower dental arches.

functional appliance A term applied to a class of removable appliances, which utilize the muscle action of the patient to produce orthodontic or orthopedic forces.

functional jaw orthopedics The form of therapy, usually with activator-type appliances, that utilizes the musculature to create dentofacial changes.

functional matrix A theory, which explains the interrelationship between osteogenesis and local functional demands, proposed by J. Moss.