imbrication An overlap of incisors and canines due to crowding.
immobilization To fix in place so that no movement is possible. Usually used in regard to orthognathic surgery.
impaction (tooth) A condition that describes the total or partial lack of eruption of a tooth well after the normal age for eruption.
impaction (surgical) A term usually used to describe orthognathic surgery involving the superior repositioning of the upper jaw. See Le Fort 1.
implant 1. Any object or material, such as an alloplastic substance or other tissue, which is partially or completely inserted or grafted into the body for therapeutic, diagnostic, prosthetic, or experimental purposes. 2. Generally an artificial structure placed into bone which provides for prosthetic replacement of some missing structure. Also used to describe a graft placed in soft tissue.
impression A negative likeness or copy in reverse of the surface of an object; an imprint of the teeth and adjascent structures for use in dentistry/ orthodontics. An impression in orthodontics is typically produced by placing an elastic compound like alginate in a preformed tray, and placing the loaded tray over the teeth until the material stiffens. The impression is removed from the mouth and may be filled with plaster to produce an exact positive reproduction of the teeth or dental arch.
incisal Pertaining to the cutting edge of the anterior teeth.
inclination The angle of the long axis of a tooth from a particular line of reference; the tilt or tip of a tooth.
inclined plane An acrylic ledge or platform which is usually added to a maxillary Hawley retainer and is designed to intrude teeth or to position the lower jaw forward.
indirect bonding A procedure for bonding orthodontic attachments to the teeth. A laboratory process is performed to position the attachments on plaster casts; the prepositioned attachments are then bonded to the teeth utilizing an elastic impression tray as a transfer device.
Individual Practice Association (IPA) A partnership, corporation or other legal entity which contracts with an HMO, union or other provider to provide care to an enrolled group for a fixed monthly amount. In the IPA, the provider can work from his office instead of an HMO center or clinic. Fee-for-service patients can be treated alongside those in the IPA plan. Patients in the IPA plan must use a participating provider. The provider must follow IPA practices, accept reimbursement as full payment and comply with IPA peer review and quality assurance procedures. Typically, the IPA pays the provider a percentage of his fee, with the remaining percentage held in a reserve pool that may be divided at year's end by the provider if any funds remain.
inelastic deformation Deformation of a member sufficiently substantial to exceed the elastic limit of the material and, upon total unloading (deactivation), the result is in a 'permanent set' (a change in geometry/shape from the passive state prior to the deformation).
infection control Measures practiced by healthcare personnel in healthcare facilities to decrease transmission and acquisition of infectious agents (e.g., proper hand hygiene, scrupulous work practices, use of personal protective equipment (PPE) [masks or respirators, gloves, gowns, and eye protection]. These guidelines are set by CDC, OSHA, etc.
informed consent An agreement by the patient or parent to proceed with or decline treatment after the benefit and risks of treatment options have been presented.
infradentale The highest and most forward point of the alveolar process between the mandibular central incisors.
infraocclusion A tooth or teeth positioned below the normal plane of occlusion.
intensifying screen A stiff sheet of plastic impregnated with a material which fluoresces when exposed to x-radiation. It is used in an x-ray cassette to intensify the x-ray image and reduce the patient's exposure to radiation. See rare earth screen.
interceptive orthodontics An extension of preventive orthodontics that may include localized tooth movement. Such treatment may occur in the primary or transitional dentition and may include such procedures as required for the redirection of ectopically erupting teeth, correction of dental crossbites or recovery of space loss where overall space is inadequate. When initiated during the incipient stages of a developing problem interceptive orthodontics may reduce the severity of the malformation and mitigate its cause. Complicating factors such as skeletal disharmonies, overall space deficiency, or other conditions may require subsequent comprehensive therapy.
interdental spacing Spacing between the teeth.
interleukins (IL) A group of proteins that function as cytokines and are regulatory of immune function. These proteins are produced as metabolites of arachidonic acid.
intermaxillary Between the upper and lower jaws.
intermaxillary anchorage (Baker’s anchorage) Anchorage in which units in one jaw are used to effect tooth movement or to apply traction on the other dental arch.
intermaxillary elastic traction Use of elastics to apply traction between the upper and lower jaws.
intermittent force An orthodontic or orthopedic force that is inactive for intervals of time during the between-appointments period, often exhibiting a cyclic, long-term, magnitude-time pattern (e.g., force exerted by an extraoral appliance worn only at night).
internal derangement An intracapsular problem of the TMJ which may relate to arthritis, fibrosis, tumors, condylolysis, condylar hyperplasia or other internal factors. This condition often reflects a displacement or malrelation of the articular disk to the condyle and articular eminence.
interocclusal clearance Synonymous with freeway space.
intramaxillary Within one dental arch.
intramaxillary anchorage A situation where a tooth or group of teeth provides anchorage to apply traction to other teeth within the same arch.
intraoral anchorage Anchorage located inside the mouth.
intraoral force Force which is generated by orthodontic appliances in the oral cavity.
intrusion A translational form of tooth movement directed apically and parallel to the long axis of a tooth.
irregularity index An assessment of the crowding of the anterior teeth developed by R. Little.
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J-hook headgear An extraoral appliance (headgear) that uses a pair of metallic hooks, each in the shape of the letter 'j,' which, when attached to a tooth or to an archwire, delivers a force bilaterally to anterior, intraoral sites.
jackscrew Synonymous with expansion screw.
jaw A common term for either the maxilla (upper jaw) or mandible (lower jaw).
jaw relationship The position of the upper jaw in relationship to the lower jaw; usually an anteroposterior or transverse assessment.
joint symptoms A generalized term that refers to various aspects of TMJ dysfunction, internal derangement or other conditions involving the TMJ.
jumping the bite A “slang” term - The correction of a crossbite brought about by horizontal movements of teeth and, occasionally, the jaw, to their correct position.
jumper A spring appliance that is attached to fixed appliances to move teeth (similar to a Herbst appliance and developed by J. J. Jasper.)
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key ridge The most inferior point on the zygomatic process of the maxilla as seen in a lateral cephalometric radiograph; the craniometric point zygomaxillare.
Kloehn headgear See Headgear.
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labial Of or pertaining to the lip. A term that describes a tooth surface facing the lips. Has the same meaning as 'facial' in the anterior portion of the dentofacial complex.
labial arch or bow A wire that traverses the labial surfaces of the teeth.
labial sulcus The furrow that lies between the lips and the alveolar process.
labial root (lingual crown) torque The third-order couple of a transverse force system applied to the crown(s) of a tooth or dental segment that has the potential for rotational displacement which results in labial movement of the root(s) and/or lingual movement of the crown(s).
labiolingual appliance A fixed orthodontic appliance that includes both facial and lingual crown attachments and archwires.
labioversion General term indicating the deviation of a tooth toward the labial.
labrale inferior Most forward point of the lower lip.
labrale superior Most forward point of the upper lip.
landmarks, cephalometric Anatomic and constructed measure points used in analysis of cephalometric radiographs.
LASER Abbreviation for Light Amplification by Stimulated Emission of Radiation. A device that concentrates light into an intense, narrow beam used to cut or destroy tissue. It is used in surgery (frenectomy, canine exposure, gingival recontouring etc.), photodynamic therapy, and for a variety of diagnostic purposes.
lateral cephalometric radiograph An x-ray taken according to cephalometric conventions with the x-ray source facing the right side of the face and perpendicular to the mid sagittal plane. The x-ray film faces the left side of the face. This radiograph is used to measure and determine sagittal and vertical craniofacial relationships. See cephalometrics.
lateral excursion Movement of the mandible away from its centric position.
leeway space The difference between the combined widths of the three buccal primary teeth (canine and two molars) and their permanent successors (canine and two premolars).
Le Fort surgical procedure Surgical procedure in which parts of the upper face are completely separated from their supporting structures and repositioned to effect corrective alignment.
Le Fort I surgical procedure A horizontal segmented fracture of the alveolar process of the maxilla, in which the teeth are usually contained in the detached portion. (Also called Guerin’s fracture)
Le Fort II surgical procedure A pyramidal fracture of the midfacial skeleton with the principal fracture lines meeting at an apex at or near the superior aspect of the nasal bones. The lateral orbital rims and nasal processes are typically intact.
Le Fort III surgical procedure A craniofacial dysjunction fracture in which the entire maxilla and one or more facial bones are completely separated from the cranial base. Also called Transverse facial fracture.
leveling A phase of comprehensive orthodontic treatment when fixed appliances are used to change the line of intercuspation from a curve to a straight line; to align the teeth in the same plane.
leveling wire Orthodontic wire, sometimes round (in cross-section) and that exhibits low flexural stiffness, used in the leveling phase of treatment.
ligament, periodontal See periodontal ligament.
ligationThe act of tying, of applying a ligature. In orthodontics the term is often used to denote tying a wire to the orthodontic brackets.
ligature A tie that secures the archwire in the bracket-slot typically annealed wire, rubber, or a polymer.
light-wire technique An orthodontic treatment modality in which the appliance components to be activated are relatively flexible. Small force values, active over long time periods are used.
limited orthodontic treatment Typically focuses on limited objectives, not necessarily involving the entire dentition. It may be directed at the only existing problem, or at only one aspect of a larger problem in which a decision is made to defer or forego a more comprehensive plan of therapy.
lingual Of or pertaining to the tongue. A term used to describe surfaces and directions toward the tongue.
lingual appliances Orthodontic appliances fixed to the lingual (toward the tongue) surface of the teeth.
lingual arch A single orthodontic wire, that traverses the lingual surfaces of the teeth, usually from molar to molar. Generally used for stabilization, as a holding arch for space maintenance, for expansion, or to provide anchorage for intermaxillary traction.
lingual frenum See frenum.
lingual retainers A variation of the lingual arch that traverses the lingual surfaces of the mandibular anterior teeth between the cuspids. The purpose is to stabilize the teeth.
lingual root (labial crown) torque The third-order couple of a transverse force system applied to the crown(s) of a tooth or dental segment that has the potential for rotational displacement which results in lingual movement of the root(s) and/or labial movement of the crown(s).
lingual version Denotes malposition of one or more teeth to the lingual; same as linguoclusion.
linguoclusion An occlusal relationship in which the position of one or more teeth is abnormally lingual. Affected teeth must be identified when this term is used.
lip bumper An appliance designed to eliminate excessive lip pressure on the anterior teeth and transfer that force to the molars. Typically consists of a labial archwire with or without an anterior plastic pad, fitted into tubes on the molars. The treatment objectives are to allow incisors to move forward and to distalize the molars, thereby increasing the arch length.
lip incompetence A gap between the relaxed upper and lower lips because of a vertical hard and soft tissue imbalance.
long-face syndrome A craniofacial pattern characterized by a long and narrow face, an increased mandibular plane angle, an anterior open bite malocclusion and lip incompetence. It is thought by some to result partly from a lack of adequate airway.
long-axis rotation A nontranslational tooth movement characterized by the coincidence of the long axis and the axis of rotation.
luxation Forceful movement or displacement of an anatomic structure. In dentistry, may describe displacement of the mandibular condyle or the intentional movement of a tooth in its alveolus with tearing of the periodontal fibers; sometimes used in an effort to free an ankylosed tooth.
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macrodontia Teeth that are larger than normal.
magnetic force Repelling and attracting forces created by small rare earth magnets, incorporated in fixed and removable orthodontic appliances to cause changes in tooth position or optimize response in functional magnetic growth guidance appliances.
MRI (Magnetic Resonance Imaging) Creation of images specifically of the TMJ for studies of articular disc position.
mal- Prefix denoting a bad or unfavorable condition. Malalignment, malocclusion, malposition and malrelation are common terms used in describing unfavorable tooth positions.
malocclusion (relationship of teeth in occlusion) A deviation in intramaxillary and/or intermaxillary relations of teeth from normal occlusion. Often associated with other dentofacial deformities. See Angle classification.
malar Relating to the cheek or cheekbone. See zygoma.
mandible The lower jaw.
mandibular resection (osteotomy) Surgical removal of a part of the mandible to allow repositioning of the remaining parts.
mandibular osteotomy Surgical sectioning of the mandible into two or more parts to allow repositioning of the resulting components.
mastication The process of chewing food for swallowing and digestion.
materia alba White accumulation or aggregation of microorganisms, desquamated epithelial cells, blood cells and food debris loosely adhered to surfaces of teeth, soft tissues, dental restorations and orthodontic appliances. Less adherent than plaque, but may change into plaque.
maxilla Paired facial bones that form the base for the upper dental arch, floor of the nose and much of the lower border of the orbit and cheek bones.
maxillary Of or pertaining to the upper jaw. May be used to describe teeth, dental restorations, orthodontic appliances or facial structures.
maxillary osteotomy Surgical sectioning and repositioning of maxillary bone structure to alter bone and jaw relationships.
maximum force An orthodontic force having the greatest magnitude within a range of force values that will produce tooth movement at a clinically acceptable rate.
mechanotherapy Orthodontic treatment with mechanical forces, that act on the dentofacial complex.
mediolateral The direction perpendicular to a sagittal plane of the dentofacial complex; the medial direction/sense is toward, and the lateral direction/sense is away from the mid-sagittal plane.
menton The most inferior point on the chin in the lateral view. A cephalometric landmark.
mesial Toward or facing the midline, following the dental arch. Used to describe surfaces of teeth, as well as direction.
mesial drift A term applied to either a natural developmental phenomenon whereby the posterior teeth continually move slightly forward as the interproximal surfaces wear or where contiguous teeth are missing and there is movement into that space..
mesioclusion An occlusal relationship in which the mandibular teeth are positioned mesially (forward) relative to the maxillary teeth, similar to the relationship in an Angles Class III malocclusion.
mesiodens A supernumerary tooth located in the midline of the maxillary alveolar process. Often unerupted, it may inhibit or otherwise disrupt eruption and the position of the incisor teeth.
mesiodistal The local direction tangent to the ideal arch form and parallel to the occlusal plane; the mesial direction/sense is toward, and the distal direction/sense is away from, the midline of the dentition.
midsagittal plane The imaginary, vertical plane that separates the left and right sides of the dentofacial complex.
miniscrews Small titanium alloy or stainless steel surgical bone screws.
mesognathic Position of jaws forward from their normal position in relation to other facial structures.
microdontia Abnormal smallness of teeth.
microglossia Presence of a small tongue.
micrognathia An abnormally small jaw.
migration (dental) Spontaneous movement of a tooth or teeth after eruption.
mixed dentition The developmental stage during which both primary and permanent teeth are present in the mouth (approximately 6 to 12 years of age).
model (dental) Popular name for a cast of a tooth or teeth, usually in plaster or similar material.
modiolus The area near the corner of the mouth where eight facial muscles converge.
moment A tendency to rotate as a result of the application of a force that is not through the center of resistance of a body. Moments are measured either as 1) the magnitude of a single applied force times the perpendicular distance the force acts away from the center of resistance, or 2) in the case of a couple, the magnitude of one of the forces of the couple times the distance between the forces of the couple.
monobloc A removable activator type orthodontic appliance.
monomer A chemical compound that can undergo polymerization.
mouthguard A removable elastic appliance used to protect the teeth and supporting tissues during contact sports.
second order movement Movement of teeth in a mesiodistal, x, direction.
third order movement Movement of teeth in a vertical, z, direction.
MS Master of Science, a degree awarded by a university graduate school, after completion of an advanced dental specialty education program.
MSD Master of Science in Dentistry, a degree awarded by a dental school after completion of an advanced dental education program.
mucoperiosteum Term used to describe the mucous membrane and the periosteum together. This is used in periodontal surgery to denote the total thickness flap.
mucosa The epithelial lining of body cavities opening to the outside. The oral mucosa lines all of the soft tissue surfaces of the mouth.
myalgia Muscle pain.
myofunctional Referring to the role of muscle function in relation to the teeth and jaws.
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nasion A cephalometric landmark on the bony profile at the junction of the frontal and nasal bones.
natural head position A standardized orientation that the head assumes when the subject focuses on a point in the distance at eye level. It is used for clinical examination of the face by anthropologists, orthodontists and maxillofacial surgeons.
neutroclusion Normal mesiodistal occlusal relationships of the buccal teeth.
nightguard A removable plastic appliance worn at night to prevent the deleterious effects of nocturnal parafunctional activity (i.e., clenching, bruxism). See mouthguard.
normal occlusion Optimal meeting of upper and lower teeth during function with no malocclusion present (such as, rotations, malpositions or abnormal jaw relationships that are encountered in Class I, Class II and Class III malocclusion categories).
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obturator A prosthesis used to close an opening. Frequently used to close the defect caused by a cleft palate.
occlusal Pertaining to the chewing surfaces of the posterior teeth. May be used to identify those tooth surfaces, as well as the direction (upward in the lower arch, downward in the upper).
occlusoapical The local direction perpendicular to the occlusal plane; also termed 'occlusogingival.'
occlusal dysfunction A term often used to describe abnormal functional forces and improper contact of maxillary and mandibular teeth. Untoward reaction beyond the teeth and investing tissues is claimed by some dentists, with the possibility of enhancing a multifactorial TMD etiology.
occlusal index A rating or categorizing system that assigns a numeric score or alphanumeric label to an individual's occlusion. There are five types: diagnostic, descriptive-epidemiological, treatment need or priority, treatment outcome, treatment complexity.
occlusal plane The imaginary surface on which upper and lower teeth meet in occlusion. It is actually a compound curved surface, but is commonly approximated by a plane (straight line in the lateral view) based on specific reference points within the dental arches.
occlusion The relationship of the maxillary and mandibular teeth as they are brought into functional contact.
onplant An anchorage fixture integrated to a bony surface beneath the soft tissue
open bite Lack of tooth contact in an occluding position. (also called apertognathia)
oral screen See vestibular screen.
orbitale The most inferior point on the lower border of the left orbit. A craniometric and cephalometric landmark.
ortho- A prefix denoting straight or correct.
orthodontic (orthopedic) Relating to correction of abnormal dental relationships, including facial structures and neuromuscular abnormalities.
orthodontic attachment An element affixed to a tooth crown that transmits force from the archwire or auxiliary to the dentition (e.g., a bracket).
orthodontic displacement Tooth movement achieved through biomechanical remodeling of the periodontal ligament and/or the alveolar bone.
orthodontic force Force generated by the orthodontic appliance that contributes to the correction of a malocclusion.
orthodontics/ dentofacial orthopedics That dental specialty which includes the diagnosis, prevention, interception, guidance and correction of malrelationships of the developing or mature orofacial structures.
orthodontist A dental specialist who has completed an advanced post-doctoral course in orthodontics which is accredited by the American Dental Association.
orthognathic Normal relationships of the jaws.
orthognathic surgery Surgery to alter relationships of teeth and/or supporting bones, usually accomplished in conjunction with orthodontic therapy.
orthopedic Correction of abnormal form or relationship of bone structures. May be accomplished surgically (orthopedic surgery) or by the application of appliances to stimulate changes in the bone structure by natural physiologic response (orthopedic therapy).
osseous Of or pertaining to bone.
ossification The process of replacing connective tissue such as cartilage and mesenchyme with bone.
ostectomy Surgical removal of a bone or part of a bone.
osteitis Inflammation of bone.
osteoblasts Cells that remodel and deposit bone. These cells arise from osteoprogenitor cells that are often located in the perivascular connective tissue.
osteoclasts A multinucleated giant cell of hematopoietic origin that has the role of removing bone.
osteoconduction 3-Dimensional structural scaffold to allow for the ingrowth of capilliaries, perivascular tissue and osteoprogenitor cells of the host into the graft. The scaffold itself is not osteoinductive and therefore cannot initiate bone formation.
osteocytes Mature osteoblasts that are encased in the bony matrix.