Bloomfield Hills, MI (Michigan) Orthodontist Roy D. McAnnally, MS, PHD, DMD

A B C D E F G H I J L M N O P R S T U V W X

AAO See American Association of Orthodontists.

abutment The teeth on either side of a missing tooth.

acrylic An organic resin, usually methyl methacrylate, commonly used for the construction of dental appliances, including orthodontic treatment and retention appliances.

activation The process of deforming an orthodontic component from its passive state, e.g., stretching elastic rubber bands or engaging a deformed arch wire in brackets to transmit force to the dentition.

Adams clasp A circumferential clasp engaged in mesiobuccal and distobuccal undercuts of individual teeth used to stabilize removable appliances.

alveolar bone The bone that surrounds and supports the roots of the teeth.

alveolar process The ridge of maxillary or mandibular bone that surrounds and supports the roots of the teeth.

amalgam A silver and mercury mixture which is used for filling decayed teeth.

American Association of Orthodontists (AAO) The AAO is a professional association of educationally qualified orthodontic specialists dedicated to advancing the art and science of orthodontics and dentofacial orthopedics, improving the health of the public by promoting quality orthodontic care, and supporting the successful practice of orthodontics.

anatomy The arrangement of the bones in the skeleton. Also the study of the arrangement of the bones in the skeleton.

anchorage A means of resisting unwanted tooth movement caused by the application of orthodontic force. Anchorage refers to the intraoral and extraoral structures that supply the resistance to unwanted tooth movement. Anchorage may be provided by intraoral structures, teeth, bone, and soft tissue, or by extraoral head gear.

Angle’s classification of malocclusion A classification of malocclusion introduced by Edward H. Angle. The governing criterion is the anteroposterior relationship of the upper and lower first permanent molars.

Angle’s Class I malocclusion A malocclusion with correct mesiodistal relationships of the first permanent molars. The mesiobuccal cusp of the maxillary first permanent molar occludes in the buccal groove of the mandibular first permanent molar. Class I is sometimes incorrectly used as a synonym for normal occlusion. However, Class I only signifies a normal sagittal relationship of upper and lower first molars. Class I malocclusions, though normal sagittally, can be abnormal in many other respects. For example, there can be excessive spacing, crowding, and rotations of teeth, excessive bite depth, crossbite, or anterior openbite.

Angle’s Class II malocclusion A malocclusion in which the lower first permanent molar is positioned distally relative to the opposing upper first permanent molar. A distal or posterior placement of the lower first permanent molar; a mesial or anterior relationship of the upper first permanent molar; or a combination of the two will result in a Class II malocclusion. The mesiobuccal cusp of the upper first permanent molar occludes mesial to the buccal groove of the lower first permanent molar, usually near the embrasure between the lower first permanent molar and second bicuspid. To classify a unilateral Class II malocclusion see subdivision.

Angle’s Class II, Division 1 An Angle Class II molar relationship in which the upper incisors are flared, proclined or positioned forward in relation to the lower incisors. This results in a marked overjet.
Angle’s Class II, Division 2 An Angle Class II molar malocclusion in which the maxillary central incisors are in close relationship to the lower incisors. Typically, upper central incisors are tipped lingually, upper lateral incisors tipped labially, and the overbite is excessive. Subdivision denotes a unilateral malocclusion, e.g., Class II, division 2, subdivision right or left.

Angle’s Class III malocclusion A malocclusion in which the lower first permanent molar is positioned mesially relative to the upper first permanent molar. A mesial or anterior relationship of the lower first permanent molar to the upper first permanent molar; a distal or posterior relationship of the upper first permanent molar to the lower first permanent molar; or a combination of the two will result in a Class III malocclusion. The mesiobuccal cusp of the upper first permanent molar will typically occlude near the embrasure between the lower first and second permanent molars.

angulation The tilt of the long axis of a tooth in a mesial or distal direction. Contrast this with inclination in which the tilt of the long axis of a tooth is in the buccolingual or faciolingual direction.

ankylosis Abnormal immobility, union or fusion. Ankylosis can occur between two bones at their articulation or between teeth and supporting alveolar bone. Pathologic fusion of the temporal bone and mandible at their articulating surfaces would result in ankylosis or abnormal immobility of the TMJ. More commonly fusion occurs between teeth and alveolar bone. In such a case, the periodontal ligament is obliterated by a ‘bony bridge’ and the tooth root is fused to the alveolar bone. Dental ankylosis prevents both eruption and orthodontic movement. In a growing child, an ankylosed tooth appears to ‘submerge’ as adjacent unaffected teeth and alveolar bone continue their normal pattern of growth occlusally.

anterior crossbite One or more upper front teeth are lingual to one or more of the opposing lower teeth in maximum intercuspation.

anterior guidance Contact of maxillary and mandibular incisors guide the mandible downward in protrusive and lateral excursive movements to separate the posterior teeth. This reduces wear and eliminates harmful lateral forces on the posterior teeth.

anterior segment All of the canine and incisor teeth in a given dental arch. The six front teeth.
anteroposterior Front to back. The anterior direction is forward. The posterior direction is rearward or back.

apical base The underlying (basal) maxillary and mandibular bone that supports and is continuous with the alveolar bone supporting the roots of the teeth. Although the demarcation between basal and alveolar bone is not specific, it is generally considered to lie at the level of the apices of the roots.

appliance Any device designed to influence the shape and/or function of the stomatognathic system. Anything the orthodontist attaches to the teeth to move the teeth or to change the shape of the jaw.
fixed appliance A bonded or banded appliance affixed to individual teeth or groups of teeth.
orthodontic appliance Any device used to influence growth or the position of teeth and jaws.
removable appliance An appliance that is freely removable from the mouth. It is not secured by cementation.

orthopedic appliance Any device used to influence the growth, size, form or position of bones.
functional appliance Any device, removable or fixed, designed primarily to effect skeletal and/or dental changes by modifying and utilizing the neuromuscular forces of the stomatognathic system. Examples include the Frankel appliance, activator, and bionator variations.

alveolar arch The U-shaped alveolar ridge that encloses the roots of teeth in either jaw.
arch The composite structure including the teeth and supporting alveolar and basal bone of either jaw. See dental arch.

dental arch The composite structure of the dentition, alveolar ridge, and basal arch.
arch circumference or arch perimeter The distance from the mesial contact of one first permanent molar to its antimere, the permanent molar on the other side, measured through the contact points or buccal cusp tips of all of the intervening teeth, ignoring those teeth that are malpositioned or blocked out so that the measurement represents an ideal arch form. See arch length.

arch depth The perpendicular distance from a point between the central incisors to a line connecting the mesial contacts of the first permanent molars. See arch length.

arch form The shape of an individual dental arch or of an arch wire formed to fit or shape that arch. An orthodontist could say that you have a U-shaped arch form or a V-shaped arch form.

arch length available and arch length required These are measurements of space available to align the teeth and required to align the teeth. Arch length and arch depth are synonymous. You should note, however, that Arch length is often used as a synonym for arch circumference or arch perimeter.
arch length deficiency The difference between the space required and the space available to align crowded teeth. See discrepancy.

arch wire or archwire A wire engaged in orthodontic attachments, usually affixed to the crowns of two or more teeth by brackets, and capable of causing or guiding tooth movement.
arch wire, sectional or segmental An arch wire that engages a limited number of adjacent teeth, perhaps only the four incisors or only a posterior dental segment.

armamentarium A general term for materials, equipment, and devices used by the orthodontist.
band, orthodontic A thin stainless steel band placed around the crown of a tooth to which orthodontic attachments are secured. The band, with orthodontic attachments welded or soldered to it, is closely adapted to fit the contours of the tooth and then cemented into place.

banding The process of cementing orthodontic bands to the teeth.
basal bone The bone that underlies, supports, and is continuous with the alveolar process. See apical base.

base, bracket The part of a bracket that is attached either to a metal band or bonding pad.
beta-titanium A beta titanium-molybdenum alloy.

bilabial protrusion Both upper and lower lips are too far forward.

bimaxillary Both the upper and lower jaws. Bimaxillary is a collective term used to describe the combination of maxilla and mandible.

bimaxillary protrusion Anterior protrusive position of both jaws in relation to other cranial and facial structures. Orthodontists refer to a bimaxillary protrusion when both jaws, the maxilla and mandible, are too far forward.

bimaxillary dentoalveolar protrusion The teeth and supporting alveolar bone in both jaws are protrusive. The basal bone and anteroposterior position of the jaws may be in normal position.
biomechanics The relationship between the forces you apply to living tissue such as teeth and gums and how the tissue responds.

bionator A modified removable functional appliance, developed by Dr. Balters to provide better control of the buccal musculature.

biteplate or bite plane A removable orthodontic appliance designed to open the bite and/or prevent selected teeth from occluding.

blocked out A tooth that is positioned away from its proper position in the dental arch due to insufficient space.

bodily movement Translational movement of a tooth or dental segment ordinarily understood to be perpendicular to the long axis/axes.

Bolton analysis A method developed by Wayne Bolton for the evaluation of tooth-size discrepancies (mesiodistal crown diameter) between the upper and lower arches.

bonding The process by which orthodontic attachments are affixed to the teeth by an adhesive.
bonding, direct An intraoral procedure in which orthodontic attachments are oriented by inspection and bonded individually to the tooth surface.

bonding, indirect A two-step process by which orthodontic attachments are affixed temporarily to the teeth of a study model and then transferred en masse to the mouth by means of a molded matrix that preserves their predetermined orientation and permits them to be bonded simultaneously.
braces See fixed appliance.

bruxism Habitual grinding or gnashing of the teeth, usually during sleep. May cause attrition of the teeth, muscle ischemia, and pain and damage to the supporting tissues. Bruxism is frequently associated with clenching and TMJ problems.

bracket A metal or ceramic orthodontic attachment that is secured to a tooth, either by bonding or banding, for the purpose of engaging an arch wire. Brackets can be fabricated from metal, ceramic or plastic.

bracket slot That portion of a bracket which receives an arch wire. Edgewise bracket slots are rectangular in cross section. Either 0.018 x 0.025 or 0.022 x 0.028 inches in dimension with the shorter dimension open go the buccal or labial.

bracket tie wing The portion of a bracket which retains a ligature.

buccal Toward the cheeks.

buccal segment All of the premolar (bicuspid) and molar teeth in a given quadrant.
buccal tube A fixed attachment which is open only at each end. Tubes may be round or rectangular in cross section. Round tubes are usually .045 inches in diameter to receive auxiliaries such as a face bow or lip bumper. Rectangular tubes are either .018 x .025 or .022 x .028 inches in diameter in order to receive arch wires and generally are placed on the most distal molar teeth in the appliance.

buccoversion Buccal malposition of a tooth or groups of teeth.

calculus A hard deposit that forms when you do not brush the teeth and plaque hardens. Calculus is also known as tartar.

caries Tooth decay.

casts, dental - study models - working models Plaster replicas or plaster models of the teeth and surrounding tissues, typically made from an alginate impression and used for diagnosis and treatment planning (study models) and appliance fabrication (working models), and as a part of the patient’s permanent record.

cavity A hole in a tooth caused by tooth decay.

centric occlusion Mandibular position dictated by maximum and habitual intercuspation of the upper and lower teeth. Centric occlusion has been variously referred to as intercuspal position, maximum intercuspal position, habitual centric, usual occlusal position. The condylar position may or may not be in harmony with centric occlusion. Because of this, the term habitual occlusion is preferable.
centric relation A gnathologic term, signifying optimal condyle-articular eminence-glenoid fossa relationships. Centric relation is determined by neuromuscular balance and temporomandibular joint relationships and not by tooth intercuspation. Changing concepts no longer accept the most retruded, rear most or hinge axis definition of centric relation, originally derived from prosthetic articulators. The condylar position can vary somewhat but is generally in a reasonably well-centered position within the temporal fossa. The bearing surface of the condyle rests upon a cartilaginous articular disk. In the mandibular rest position the condyle is somewhat high along the posterior slope of the articular eminence and separated from the eminence by 2.5 mm, the thickness of the articular disk. The average superior and posterior joint space ranges between 3.0 to 3.4 mm. This space contains the supratemporal artery and auriculotemporal nerve. Any discrepancy or lack of harmony between centric occlusion and centric relation is particularly important in the diagnosis and management of TMJ problems.

cephalogram or ceph An abbreviated synonym for a cephalometric radiograph. The term is sometimes used to refer to a fine-line tracing of the salient craniomandibular structures, landmarks and pertinent measurements on an acetate film overlay. The linear and angular measurements are used for diagnostic purposes. Today, the salient structures and landmarks can be captured directly with digital radiography. X-ray film is eliminated and measurements can be derived using computerized cephalometry programs.

cephalometric analysis The process of evaluating dental and skeletal relationships using linear and angular measurements obtained directly from the living head or, more commonly, from cephalometric radiographs and tracings. Standardized sets of cephalometric measurements are commonly used in the evaluation.

cephalometric radiograph An X-ray of the head that allows linear and angular measurements of the teeth, jaws, and other facial and cranial structures. The cephalometric radiograph is also called a cephalometric x-ray, a lateral skull radiograph or lateral skull x-ray, or simply a ceph. It is used to assess the structural development and compare an individual’s development to normal standards. A standardized radiograph of the head is characterized by a precisely defined relationship between x-ray source, subject and film. By convention, the distance between x-ray source and the center of the subject, midsagittal plane or transporionic axis, is either 5 feet or 1 52.4 cm. The distance between the midsagittal plane or transporionic axis of the subject and film is approximately 12 cm but may be standardized at a different value, or varied according to head size and recorded for each exposure. The standard projections are a lateral profile and posteroanterior (P-A).

ceramic brackets Crystalline alumina tooth-shade or clear synthetic sapphire brackets. These brackets are commonly considered esthetically more pleasing than metal brackets.
chain, orthodontic – C-chain, power chain, or elastomeric chain A elastic ligating chain used to apply traction and close spaces between teeth.

clenching Nocturnal parafunctional activity of temporalis, masseter and pterygoid muscles that is considered to be part of a stress-strain-tension release syndrome. Clenching is frequently associated with bruxism and temporomandibular joint disturbances.

clicking A term applied to abnormal sounds emanating from one or both temporomandibular joints, usually due to anterior or anteromedial or anterolateral displacement of the articular disk during functional movements.

closed bite A malocclusion with excessive vertical overlap of the anterior teeth. Also called a deep bite or referred to as excessive bite depth.

comprehensive orthodontic therapy The coordinated diagnosis and treatment leading to the correction of craniofacial dysfunction, dentofacial deformity, and dentoalveolar malocclusion. Anatomic, functional and esthetic relationships are optimized. Treatment usually, but not necessarily, utilizes fixed orthodontic appliances. Adjunctive procedures such as extractions, maxillofacial surgery, nasopharyngeal surgery, myofunctional or speech therapy, and restorative or periodontal care require coordination of disciplines. Optimal care requires long term consideration of a patient’s needs and periodic reevaluation. Treatment may incorporate several phases with specific objectives at various stages of dentofacial development.

computerized axial tomography (CAT scan) Images made by computed tomography. Anatomical information from a cross-sectional plane of the body is derived by computer synthesis of an image from x-rays.

conditioner (also Acid etch) A weak solution of orthophosphoric acid placed on the surfaces of the teeth to prepare the tooth surfaces for bracket bonding. The conditioner increases the adhesion of brackets to the tooth surfaces.

condyle The superior portion of the ramus of the mandible that articulates with the temporal eminence in the glenoid fossa. The mandibular condyle articulates with the temporal bone of the skull in front of the ear.

condylar displacement A functional abnormality in which one or both mandibular condyles are displaced from their normal relationships with their articular disks and eminentia in the glenoid fossae as the mandible closes into habitual occlusion.

condylar guidance The functional movements of the mandible are guided by the morphology of the mandibular condyles, the articular disks, and the temporal eminentia in the glenoid fossae.
condylar growth Proliferation of condylar cartilage, followed by its endochondral ossification. The condyle is a site of growth that is important to the overall development of the mandible. Condylar growth normally stops shortly after that of the rest of the face, although it may continue well beyond adolescence, particularly in males, or it may stop and begin again.

consultation (also diagnostic and treatment planning conference) A meeting with the orthodontist to discuss the diagnostic findings, treatment recommendations, alternative plans of treatment, their potential benefits, risks, estimated treatment times, and mechanotherapies. Progress consultations may also be held to discuss the progress of treatment, difficulties encountered, and possible alterations in the treatment plan.

continuous orthodontic force Action of an appliance against the dentition that decreases little in magnitude between appointments.

cosmetic orthodontics Orthodontic therapy whose purpose is improving the appearance of the face, teeth, and smile.

cranial base The endochondral bone that forms the anteroinferior aspect of the brain case. Because the bones of the cranial base stop growing relatively early, they are often used in the superimposition of serial cephalograms or tracings.

crepitus In orthodontics, a grating or grinding sound in a moving temporomandibular joint. Crepitus has been likened to the sound of crumpling dry leaves or rubbing two bricks together.

crossbite An abnormal relationship of a tooth or teeth to the opposing teeth in which normal buccolingual or labiolingual relationships are reversed. A malocclusion where one or more upper teeth are inside the lower teeth when you bite down.

crowding Inadequate space for the teeth leading to misalignment of teeth. The sum of the mesiodistal widths of the teeth in an arch exceeds the arch circumference.

crown An prosthetic or artificial replacement for the outer structures of a tooth, usually shaped from gold, ceramic or porcelain to resemble a natural tooth.

curve of Spee When viewed from a lateral or sagittal perspective, the occlusal and incisal surfaces of the teeth in both dental arches collectively describe a curve. The concave aspect of the curve of the mandibular arch faces upward. The convex aspect of the curve of the maxillary arch faces downward.

curve of Wilson Because the long axes of the mandibular molars and premolars converge towards the midline, the occlusal surfaces of these teeth bilaterally form a curve in a buccolingual direction. This imaginary curve as defined by lines tangent to the buccal and lingual cusps of the mandibular posterior teeth bilaterally is termed the curve of Wilson.

debanding The removal of cemented orthodontic bands.

debonding The removal of bonded orthodontic attachments.

decalcification The loss of calcium from the surfaces teeth. Surface erosion resembles “white rust” and can lead to deeper decay.

DDS, Doctor of Dental Surgery, and DMD, Doctor of Dental Medicine. The degrees are awarded by dental schools to graduates of doctoral dental programs. Some dental schools grant the DDS degree. Others grant the DMD degree. The two degrees are equivalent.

deep bite Excessive vertical overlap of upper and lower front teeth. Also referred to as excessive overbite or closed bite.

dehiscence A clefting defect in the gingival margin of a tooth; a type of gum recession.
dental plaque Colonized bacteria growing in a thick, mucous-like glycan, also referred to as a mucopolysaccharide matrix. Plaque removal is accomplished by tooth brushing and use of dental floss after eating. Failure to regularly remove plaque can lead to caries, gum inflammation, and periodontal disease.

dentition A collective term for the teeth. The character of a set of teeth especially with regard to their number, kind, and arrangement.

dentition, primary The first set, primary, deciduous, or “baby” teeth. These are the first teeth to develop and erupt into the mouth. These teeth are normally replaced by permanent successors.

dentition, adult The adult teeth.

dental or dentoalveolar malocclusion A malocclusion characterized by abnormally positioned teeth and supporting alveolar bone. The size, shape, and position of craniofacial bones are within the normal range. A dental malocclusion in which the teeth are not in their correct positions can be contrasted with a skeletal malocclusion in which the craniofacial bones are not within their normal range.

dentofacial deformity Dentofacial malformation characterized by one or more of the following: Disharmonies in size, form and position of skeletal structures, malocclusion, cleft lip or palate, and other skeletal or soft-tissue deformities. These deformities may be accompanied by various types of muscular dysfunction.

dentofacial orthopedics The treatment of the skeletal aspect of malocclusions. Dentofacial orthopedics and orthodontics more fully describes the scope of a contemporary orthodontic practice. See orthodontic.

developmental guidance See guidance. Preventive, interceptive, and corrective dentofacial orthopedic and orthodontic supervision and growth guidance during the primary and mixed dentitions to maturity. Services insure that growth and development of the craniofacial complex, including the occlusion, proceeds normally.

diagnosis The process of identifying the nature of a disorder. A statement or conclusion from such an analysis.

diastema A space between two teeth.

disocclusion Separation of opposing occlusal surfaces as the mandible moves into different functional positions.

discrepancy, arch length Arch length deficiency.

displacement Any movement of a particle or a body as a whole.

distal Behind or towards the back of the mouth. You might say that the first bicuspid is distal to the cuspid. A direction oriented along the dental arch away from the dental midline: right or left in the anterior segment; posteriorly in the buccal segments.

distal segment Synonymous with posterior segment.

distocclusion Lower teeth occluding distal to their normal relationship to the uppers, as in an Angle Class II malocclusion.

distoversion A term sometimes used to describe a tooth positioned distal (posterior) to its normal position.

drift See mesial drift. Teeth exhibit a physiologic mesial drift.

dysfunction Impaired or abnormal function.

dysplasia Abnormal development.

E-space The difference between the mesiodistal widths of the primary second molar and the second premolar (second bicuspid). Generally the permanent second premolar is smaller than the primary second molar.

early orthodontic treatment Orthodontic treatment started while patient is still in the primary or transitional dentition. Permanent teeth are not fully erupted.

ectopic Located away from normal position; often used to describe a condition in which a tooth develops, erupts, or rests in an abnormal position.

ectopic eruption Any tooth can erupt ectopically. When applied to the first permanent molar, it describes a condition wherein the first permanent molar erupts with excessive mesial angulation. This often results in resorption of the second primary molar and lack of full eruption of the first permanent molar.

edentulous Without teeth. All of the teeth are missing from either the upper or lower jaw.
edge-to-edge occlusion An occlusion in which the anterior or posterior teeth of both jaws meet along their incisal or buccal cuspal edges. Often associated with a Class III molar relationship.

edgewise appliance A fixed orthodontic appliance characterized by attachment brackets with a rectangular slot for engagement of an orthodontic wire. The most common appliance in use today.

elastic Capable of recovering size and shape after deformation. Capable of ready change or easy expansion or contraction : not rigid or constricted. A flexible appliance element that exhibits substantial elastic range.

elastics (rubber bands) Elastomeric bands used to provide orthodontic traction. Class I elastics, Class II elastics, Class III elastics, vertical elastics, and diagonal or cross-elastics describe the elastic connections and force vectors. Usually made of latex.

elastomeric ligature An elastic band or thread that is stretched around the tie-wings of an orthodontic bracket to prevent disengagement of an arch wire or auxiliary from the bracket slot.

endodontist (Endo) A dentist who specializes in root canals and the treatment of diseases or injuries that affect the root tips, nerves, and blood vessels within the teeth.

equilibrate Reshaping the occlusal (functional) surfaces of the teeth. Equilibration may be undertaken to eliminate bite interferences, redistribute and balance the functional load on the teeth, or for esthetic reasons.

erupt, eruption Movement of teeth in an incisal or occlusal direction through the supporting bone and gingival tissue into the oral cavity. A new tooth is said to erupt when the tooth breaks through the surface of the gums and can be seen in the mouth.

exfoliate To fall out. The deciduous teeth exfoliate and permanent teeth erupt into the space.

esthetics, facial See facial esthetics.

etch The application of a weak acidic solution to the labial or lingual surfaces of teeth as part of the preparation for bonding orthodontic attachments to the teeth.

etiology The cause of a medical or dental condition.

exfoliate Physiological loss or shedding, as when a primary tooth is lost prior to the eruption of the permanent tooth.

expansion Enlargement; often used to describe the mechanical widening of the dental arches.

expansion screw A mechanical device incorporated in a removable appliance or a fixed appliance used to enlarge the dental arch in some dimension.

expansion, rapid palatal (RPE) See rapid palatal expansion.

extraction Removal of a tooth.

extraoral Outside of the mouth. For example, head gear is said to be extraoral since it is an orthodontic auxiliary that is used outside of the mouth.

extraoral anchorage Anchorage that is located outside the mouth.

extraoral force or traction Force originating outside the oral cavity.

extraoral photographs Facial photographs used for the assessment of facial form.

extrusion A translational form of tooth displacement with movement directed occlusally and parallel to the long axis.

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

facial form The configuration, shape or appearance of the face.

facial growth The developmental process leading to maturation and 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.

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

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

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.

fluoride A chemical solution or gel applied to the teeth to harden the teeth and help prevent tooth decay.

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, intraoral, extraoral, orthodontic, orthopedic, elastic, spring, magnetic, etc. depending on the need.

fossa, glenoid See glenoid fossa. The concavity within the temporal bone in front of the ear within which the condyle of the mandible rotates and translates during movements of the lower jaw.

Fränkel appliance An activator type functional appliance 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 rest position.

frenectomy The surgical removal or repositioning of a frenum or frenal attachment. 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 the lip, cheek or tongue to the alveolar mucosa. There are both labial and lingual frenal attachments.

friction A resistance to the relative displacement of contacting bodies in a direction tangent to the plane of contact. Resistance aids anchorage but impairs translational movements of teeth.

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 of upper and lower dental arches.

functional appliance A term applied to a class of removable appliances which utilizes 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 (bone formation) and local functional demands, proposed by J. Moss. The functional matrix is the entire structural and functional milieu of the tissues enclosing or enveloping the developing bone.

functional occlusion An arrangement of the teeth intended to minimize stress on the temporomandibular joint; maximize function, stability and esthetics of the teeth; and provide for protection and health of the periodontium.

gingiva The tissues that surround the teeth, consisting of a fibrous and vascularized zones of tissue that are continuous with the periodontal ligament and mucosal covering of the alveolar bone.

gingival attachment The fibrous attachment of the gingiva to the teeth.

gingival display A vertical measure of the amount of gingiva (gum) visibly seen above the upper front teeth when smiling. See gummy smile.

gingival hypertrophy The abnormal enlargement of the gingiva surrounding the teeth caused by poor oral hygiene.

gingival recession Shifting of the gingival margin apically exposing part of the root of the tooth.

gingivitis Inflammation of the gingiva. Inflammation of the gums caused by improper brushing. The first sign of periodontal or gum disease.

glenoid fossa The depression or fossa in the temporal bone in which the condyle of the mandible is positioned. Part of the temporomandibular joint (TMJ).

grinding A term synonymous with bruxism or parafunctional activity.

growth An age-related increase in size.

guidance, developmental A planned orthodontic and orthopedic effort to influence the growth of the jaws and eruption of the teeth, with the objective of guiding abnormal development into a normal situation. This generally requires a combination of carefully timed appliance therapies and supervisory examinations throughout progressive stages of development. This may be required from the earliest date of detection of a developing malformation until the craniofacial skeleton is mature.

gummy smile A popular term for excessive exposure of maxillary gingival tissue during a full smile, usually caused by excessive maxillary vertical height.

habit In dentistry a term applied in a negative sense to frequently repeated activity such as finger or lip sucking or tongue thrusting. Such activity may alter the normal development of the teeth or bones.

habit therapy Treatment designed to prevent potentially deforming finger, lip, or tongue habits and/or correct a malformation of the teeth or bones caused by a habit. Treatment might occur by counseling, appliance therapy, or both.

habitual occlusion Habitual occlusion is closure into maximum intercuspation or the “best fit of the teeth.” The “best fit of the teeth” may or may not be consistent with “correct fit of the teeth.” Both malocclusions and normal occlusions close into the “best fit of the teeth.” Habitual occlusion may or may not coincide with centric relation. When an incompatibility exists between the “best fit of the teeth” and the “best fit and function of the TM joints” the teeth and habitual occlusion are dominant, take precedence over normal TMJ and neuromuscular function, and the TM joints and masticatory muscle function suffer. The result is a temporomandibular disorder (TMD) and/or myofascial pain disorder (MPD). To put it simply, “When the teeth are not in their correct positions, they (the teeth) can force the jaw out of its correct position.” The result is TMD and/or MPD. The goal of treatment is to establish compatibility between teeth, joints, and muscles.

Hawley appliance A Hawley retainer modified to obtain minor orthodontic corrections.

Hawley retainer A passive removable acrylic and wire appliance generally used to stabilize teeth in their new position after orthodontic correction. See retainer.

headgear An apparatus that is used to deliver traction force to the teeth derived from anchorage outside the oral cavity. A headgear consists of three parts: a face bow, a head gear force module, and either a neck strap or a high-pull, occipital-pull, or cervical-pull head cap.

Herbst appliance A fixed or removable appliance designed to advance and center the mandible. The appliance postures the jaw forward to stimulate sagittal correction of retrognathic Class II skeletal malocclusions.

holding arch See lingual arch. A space maintainer designed to prevent forward drift of posterior teeth.
hooks Attachments soldered or welded to arch wires for the placement of elastics, headgear, or elastic chains.

hyperplasia Tissue enlargement through multiplication of cells, Hyperplasia is often a response to inflammation or drugs.

hypertrophy An increase in tissue bulk through an increase in size of the tissue elements.
hypoplasia Incomplete development of a tissue or structure.

ideal occlusion A theoretical placement of the teeth in the dental arches which maximizes esthetics, function, stability, and longevity of the dentition and supporting structures. No malocclusion is present.

idiopathic An adjective that connotes an unknown etiology or causation. Pain, disease, or disorder caused by unknown factors.

immobilization To fix in place so that no movement is possible. Usually used in regard to orthognathic (jaw) surgery.

impacted tooth A tooth that failed to erupt into the oral cavity. In orthodontics this often describes maxillary canines and third molars or “wisdom teeth” that occupy positions in which normal eruption is highly unlikely.

impaction, tooth A condition describing the total or partial lack of eruption of a tooth well after the normal age for eruption.

implant A prosthetic metallic root is surgically inserted into the jaw bone. When the metallic root is secure, a replacement crown resembling a natural tooth is attached to the implanted root.

impression A negative image of a tooth or dental arch. An impression is produced by placing an elastic compound like alginate in a preformed tray and inserting the tray into the mouth around the teeth until the compound stiffens. The impression is removed from the mouth and filled with plaster to produce an exact positive reproduction of the teeth or dental arch.

incisal Pertaining to the cutting edge or surface of the anterior teeth. The biting edge of the central and lateral incisors.

inclination The tilt of the long axis of a tooth in the buccolingual or faciolingual direction. Often called torque. Contrast this with angulation, the tilt or tip of the long axis of a tooth in a mesial or distal direction.

inclined plane An acrylic ledge or platform which is usually added to a maxillary Hawley retainer and is designed to intrude anterior 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.

infection control An important aspect of any health service. Guidelines are set by the Communicable Disease Center (CDC), the Occupational Safety and Health Association (OSHA), and other local, state, and federal agencies.

informed consent An agreement by the patient or parent to proceed with or decline treatment after the potential benefits and risks of treatment have been presented.

infraocclusion (Also spelled infracclusion) 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 in an otherwise normal dentition. Such treatment may occur in the primary or transitional dentition and may include such procedures as the redirection of ectopically erupting teeth, correction of isolated dental crossbite, or recovery of recent minor space loss where overall space is adequate. Early intervention can simplify or eliminate the need for later, more complicated treatment.

interdental spacing Spacing between the teeth.

interdigitation Intercuspation.

intermaxillary Between the upper and lower jaws.

intermaxillary anchorage Using one dental arch as anchorage 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 applied occasionally or periodically as opposed to continuously.

internal derangement An anatomic displacement or malposition of the articular disk and/or condyle relative to the temporal fossa and articular eminence. Malposition of anatomic structures within the temporomandibular joints may be due to the occlusion or may be due to arthritis, fibrosis, tumors, trauma, condylosis, condylar hyperplasia, and other internal factors.

interocclusal clearance Synonymous with freeway space.

interocclusal bite registration Bite marks in a wax wafer which are used to see how the teeth come together.

interproximal Between adjacent teeth.

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 Inside or within the oral cavity.

intraoral anchorage Anchorage located inside the mouth.

intraoral force Force which is generated by orthodontic appliances in the oral cavity.

intrusion Movement of a tooth back into the bone. A translational form of tooth movement parallel to the long axis of the tooth and directed apically or toward the root tip.

jackscrew Synonymous with expansion screw.

jaw A common term for the maxilla, the upper jaw, and mandible, the lower jaw.

jaw relationship The position of the upper jaw in relationship to the lower jaw; an anteroposterior, transverse, or vertical assessment.

joint symptoms A general term referring to subjective evidence of a disease or disturbance of joint function. Clenching and grinding of teeth, microtrauma, macrotrauma internal joint derangement, or internal pathologic conditions may result in TM joint symptoms. Contrast subjective symptoms with objective signs of disorder.

jumping the bite The correction of a crossbite brought about by buccolingual movements of the posterior teeth and/or transverse movement of the jaws to their correct positions in the case of posterior crossbite; or labiolingual movement of anterior teeth and/or sagittal movement of the jaws in the case of anterior crossbite.

labial Of or pertaining to the lip. Identifies a surface facing the lips. The same as ‘facial’ in the anterior portion of the dentofacial complex. The tooth surface facing the lips.

labial arch or bow A wire that traverses the labial surfaces of the teeth.

labial root (lingual crown) torque The third-order couple of a force system applied to the crown(s) of a tooth or a dental segment having the potential for displacement resulting in labial movement of the root(s) and/or lingual movement of the crown(s).

labioversion General term indicating the deviation of a tooth toward the labial.

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 midsagittal 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 lower jaw away from the middle position.

leeway space The difference between the combined widths of the three buccal primary teeth, the primary canine, and first and second primary molars, and their successors, the permanent canine, and permanent first and second premolars (bicuspids).

leveling The initial phase of comprehensive orthodontic treatment using fixed appliances designed 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, ordinarily round in cross-section and exhibiting low flexural stiffness, used in the leveling phase of treatment.

ligament, periodontal See periodontal ligament. The fibrous attachment of the cementum of the root to the supporting alveolar bone. The attachment is comprised of one-half mm radial fibers that extend from the cementum of the root to the alveolar bone.

ligating module A small elastomeric O-ring used to hold the arch wires in the brackets on braced teeth.

ligature A tie used to secure the arch wire to the brackets on individual teeth. Ligatures are usually made of annealed wire, rubber, or a polymer. The tie secures the archwire in the bracket slot.

Ligatures are also used to secure removable lingual arches, lip bumpers, etc. to their respective attachments.

light-wire technique The use of light, continuous forces to move teeth. An orthodontic treatment modality in which the appliance components to be activated are relatively flexible, resulting in relatively small force values, active over long time periods.

limited treatment Orthodontic treatment with limited objectives. Treatment usually does not involve the entire dentition. It may be directed at the only existing problem, or at only one aspect of a complex problem produced by a variety of elements or causes in which a decision is made to defer or forego more comprehensive therapy.

lingual Of or pertaining to the tongue. A term used to describe surfaces and directions toward the tongue. The tooth surface facing the tongue.

lingual arch A single orthodontic wire usually located in the lower arch, traversing 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 intramaxillary or intermaxillary traction.
lingual frenum See frenum.

lingual retainers A variation of the lingual arch traversing the lingual surfaces of the lower teeth between the cuspids. The purpose is to stabilize the teeth.

lingual root (labial crown) torque The third-order couple of a force system applied to the crown of a tooth or dental segment having the potential for displacement resulting 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.

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, increasing the arch length.

lip incompetence An absence of lip seal at postural rest, i.e., when relaxed. A gap between the relaxed upper and lower lips because of a vertical hard and soft tissue imbalance.

MRI (Magnetic Resonance Imaging) of the TMJ The creation of images for the study of articular disc position.

mal- Prefix denoting a bad or unfavorable condition. Misalignment, malocclusion, and malposition are common terms used in describing unfavorable tooth positions.

malocclusion An unfavorable or “bad bite.” Intramaxillary and/or intermaxillary relationships of teeth deviate from normal occlusion. Malocclusion is often associated with other dentofacial deformities. See Angle’s classification of malocclusion.

mandible The lower jaw.

mandibular Pertaining to the lower jaw.

mandibular buccal crossbite One or more teeth in a mandibular buccal segment are buccal to opposing teeth in the maxillary buccal segment. Less common than a maxillary palatal crossbite.

mandibular osteotomy Surgical sectioning of the mandible into two or more parts to allow repositioning of the parts.

masticate To chew food and mix the food with saliva.

maxilla The upper jaw. 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 Pertaining to the upper jaw. May be used to describe teeth, dental restorations, orthodontic appliances, or facial structures.

maxillary palatal crossbite One or more teeth in the maxillary buccal segment are usually lingual to one or more or the opposing teeth in the mandibular buccal segment in maximum intercuspation. More common than a mandibular buccal crossbite.

maximum force The largest orthodontic force that will produce tooth movement at a clinically acceptable rate.

mechanotherapy The application of mechanical forces to correct dentofacial and orthodontic abnormalities.

mediolateral The global direction perpendicular to a sagittal plane of the dentofacial complex; the medial direction is toward and the lateral direction is away from the midsagittal plane.

mesial A directional term with reference to the dental arch denoting toward or facing the midline in the front of the mouth. Mesial is used to describe surfaces of teeth as well as direction. For example, the cuspid is mesial to the bicuspid (direction). The mesial surface of the bicuspid is closest to the midline (surface).

mesial drift A term applied to either a natural physiologic phenomenon whereby the posterior teeth continually move slightly forward as the interproximal surfaces wear or where contiguous teeth are missing and there is mesial movement of posterior teeth into that space.

mesioclusion An occlusal relationship in which the lower teeth are positioned mesially relative to the upper teeth, similar to the relationship in an Angle Class III malocclusion.

mesiodistal The local direction tangent to the ideal arch form and parallel to the occlusal plane; the mesial direction is toward and the distal direction is away from the dental midline.

midline The median line or median plane through the very center of the mouth that separates the right and left sides of the mouth. The midline passes between central incisors if the face is symmetrical.
midsagittal plane The imaginary vertical plane that separates the left and right sides of the dentofacial complex.

mixed dentition The developmental stage during which both primary or deciduous 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.

mouth guard A removable elastic appliance used to protect the teeth and supporting tissues while engaging in contact sports.

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.

nickel-titanium or Ni-Ti Arch wires made of a nickel-titanium alloy which deliver a much lower force for a given amount of deflection than comparable wires made of resilient stainless steel.

night guard A removable plastic appliance worn at night to prevent deleterious effects of nocturnal parafunctional activity, e.g., clenching and bruxism. See mouth guard.

normal occlusion Optimal meeting of upper and lower teeth during function with no malocclusion present. There are no rotated, tipped, spaced or crowded teeth. Malpositioned or abnormal jaw relationships that are encountered in Class I, Class II and Class III skeletal malocclusions are absent. The Angle relationships of teeth are normal. Andrew’s six keys to normal occlusion are present.

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 and downward in the upper arch. The chewing or grinding surfaces of the bicuspid and molar teeth.

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 upper and lower teeth. Untoward reaction beyond the teeth and investing tissues can include TMD.

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 gently curved plane or gently curved line in the lateral view. The occlusal plane is based on specific reference points within the dental arches.

occlusal radiograph The only x-ray that is taken without a precision x-ray holder. The x-ray film for this procedure is shaped like a large oatmeal cookie. You are asked to bite on the x-ray film and the top of the x-ray machine is positioned over the nose for a maxillary occlusal x-ray or under the chin for a mandibular occlusal film. The x-ray shows the whole arch.

occlusion The relationship of the maxillary and mandibular teeth as they are brought into functional contact.

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open bite A malocclusion in which some teeth cannot be brought into contact with opposing teeth and no vertical overlap is present. Bite depth, whether open or closed, is a vertical relationship. Open bite contrasts with a closed bite or deep bite.

open bite, functional Failure of incisors to contact in maximum intercuspation even though vertical overlap is present. Shim stock will slip freely between upper and lower incisor teeth.

oral Pertaining to the mouth.

ortho- A prefix denoting straight or correct.

orthodontic and orthopedic Relating to correction of abnormal dental relationships including facial structures and neuromuscular abnormalities.

orthodontic appliance Any device used to move teeth or influence the shape of the jaw. Orthodontic appliances include braces, Invisalign aligners, expanders, and other dentofacial orthopedic and functional appliances.

orthodontic attachment The element affixed to the tooth crown that transmits force from the arch wire or auxiliary to the dentition, e.g., a bracket.

orthodontic displacement Biomechanically induced tooth movement achieved through remodeling of the periodontal ligament and/or the alveolar bone.

orthodontic force Force generated by an 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 licensed dental specialist who has completed an advanced post-doctoral course, accredited by the American Dental Association of at least two academic years in the specialty area of dentofacial orthopedics and orthodontics. Licensed by the State of Michigan following academic specialty training within an accredited dental school orthodontic specialty program and passage of the State specialty examination.

orthognathic surgery Surgical repositioning of one or both jaws to alter the relationships of teeth and supporting bones. Orthognathic surgery is usually done in conjunction with orthodontic repositioning of the teeth.

orthopedic Correction of abnormal form or relationship of skeletal structures. May be accomplished surgically (orthopedic surgery) or by the application of appliance force to stimulate physiologic changes in the skeletal structure (orthopedic therapy).

osseous Of or pertaining to bone.

osteotomy Surgical procedure involving the cutting of bone.

overbite Vertical overlap of upper teeth over lower teeth. Overbite usually refers to incisor teeth and is measured perpendicular to the occlusal plane.

overjet Horizontal projection of upper teeth beyond the lower teeth. Overbite generally refers to incisors and is measured parallel to the occlusal plane. When not otherwise specified, the term is generally assumed to refer to central incisors and is measured from the labial surface of the lower tooth to the lingual surface of the upper at the level of the edge of the upper incisor. Unique conditions may sometimes require other measuring techniques. In Class III malocclusion, overjet is recorded as negative.

palatal expander An expansion device used to widen the upper jaw.

palate The bone and soft tissue closing the space encompassed by the upper alveolar arch, with a posterior extension to the pharynx. The palate forms the roof of the mouth and is connected to the nasal septum and floor of the nose in the midline.

palate, hard The anterior part of the palate that is supported by and includes the palatal extensions of the maxillary and palatine bones.

palate, soft The part of the palate lying posterior to the hard palate composed only of soft tissues without underlying bony support.

panoramic radiograph A radiographic tomograph of the jaws, taken with a specialized machine designed to present a panoramic view of the full circumferential length of the jaws on a single film. Also know by several proprietary brand names of machines, most of which include ‘pan’ as a part of the name. Also termed panoral or panorex.

papilla (interdental) The gingival structures occupying the space between adjoining teeth.
pedodontist (Pedo) A dentist who specializes in children’s dentistry.

periapical Pertaining to the area and tissues around the apex (tip) of the root of a tooth. Periapical X-ray is an X-ray of individual teeth or groups of teeth.

periodontal ligament The periodontal membrane which serves a ligamentous function in the attachment of the tooth root to the alveolar bone.

periodontal membrane or ligament The fibrous tissue that occupies the space between the root of the tooth and alveolar bone. The periodontal membrane provides a ligamentous attachment of the tooth to the bone and nourishment to the cementum surface of the root and the cells that permit tooth movement.

periodontal pocket A periodontal disease condition characterized by an abnormally enlarged space between tooth root and alveolar bone, destruction of the membranous periodontal attachment, and invasion of the space (pocket) by oral epithelium. Periodontal pockets are often progressive and result in bone and tooth loss if not arrested by treatment.

periodontics The dental specially concerned with the maintenance of the health and integrity of the periodontal tissues that support the teeth.

periodontist A dentist who specializes in the treatment of gum disease.
periodontium The investing and supporting tissues of the teeth; the periodontal membrane and alveolar process.

permanent dentition Those teeth that succeed the primary teeth and the additional permanent molars.
pharynx That part of the respiratory tract extending from the larynx to the nasal cavity; the throat is a part of the pharynx.

posterior Situated behind. In dentistry, an adjective used to describe the back of the mouth or the back teeth.

posterior crossbite More commonly, one or more teeth in the maxillary buccal segment are usually lingual to one or more or the opposing teeth in the mandibular buccal segment in maximum intercuspation. Less commonly, one or more teeth in a mandibular buccal segment are buccal to opposing teeth in the maxillary buccal segment. The former is referred to as a maxillary palatal crossbite; the latter as a mandibular buccal crossbite.

postural rest position The position of the mandible when the masticatory muscles are relaxed. The mandible assumes the postural rest position after saying any of the following words aloud: Mississippi, house, church, judge.” See freeway space, rest position.

preventive orthodontic treatment Dental services intended to prevent the development of a malocclusion by maintaining the integrity of a normally developing dentition. Typical services include dental restorations, temporary prostheses to replace prematurely lost primary teeth (space maintainers), and removal of primary teeth that fail to shed normally when the removal of these teeth will allow their permanent successors to erupt satisfactorily.

primary dentition See dentition.

primate space Space mesial to the maxillary primary canines and distal to the mandibular primary canines in the primary dentition. Primate space aids eruption of the larger permanent canines (cuspids). Absence of primate space in the primary and mixed dentitions usually leads to anterior crowding.

proclination Forward inclination of anterior teeth as opposed to bodily protrusion. An experienced practitioner can gage proclination by visual inspection or radiographic cephalometric analysis.

proclined A forward inclination of an incisor tooth.

prognathic A forward position of the mandible or maxilla relative to other craniofacial structures.

prognathism See prognathic.

prosthodontist A dentist who specializes in the replacement of missing teeth.

protraction Anterior movement of the teeth and/or bones of the face.

protrusive or procumbent The state of being forward or anteriorly positioned. Usually a forward position of incisor teeth. Protrusion can be gauged by careful visual inspection or radiographic cephalometric analysis.

proximal Refers to the surfaces of teeth that touch the next tooth. The space between adjacent teeth is the interproximal space.

proximal segment In surgery that portion of a sectioned mandible containing the articulating portion.

radiograph A permanent image, typically on film, produced by ionizing radiation. Commonly called an x-ray after the most common source of image-producing radiation.

radiographic imaging The process of acquiring representations of structures using ionizing radiation.

rapid palatal or rapid maxillary expansion (RPE, RME) An orthopedic procedure using a fixed or removable appliance to separate the two maxillary bones at the midpalatine suture.

reciprocal anchorage The use of equal and opposite equilibrium forces exerted by an appliance to produce desired tooth movements on different teeth.

records appointment An appointment to acquire X-rays, photographs of the teeth and face, and study model impressions of the teeth. These records and a clinical examination are used to diagnose the treatment needs and plan the treatment.

reproximation, also slenderization or interproximal reduction (IPR) Reduction of small amounts of enamel from the proximal surfaces of the teeth. Reproximation eliminates or minimizes crowding by reduction of mesiodistal tooth widths. It is a safe procedure when undertaken by an experienced practitioner. Reproximation often offers an alternative to tooth extraction in crowded dentitions.
resection Surgical removal of part or all of a structure.

resorption Physiologic or pathologic removal of hard tissue, bone or root, by the resorptive activity of osteoclasts.

rest position The normal resting position of the mandible, with teeth apart and muscles relaxed.

retainer Any orthodontic appliance, fixed or removable, used to maintain the position of the teeth following corrective treatment.

retention The passive treatment period following active orthodontic correction during which retaining appliances may be used.

retraction Posteriorly-directed orthodontic or orthopedic movements of teeth or bones of the face. Retraction mechanics include lip bumpers, headgear wear, distalizing appliances, extraction site closure, or Class II elastic mechanics. Contrast retraction with protraction or anteriorly-directed orthodontic or orthopedic movements.

retroinclination A palatal or lingual (backward) inclination of teeth. Retroclined central incisors are most common in Class II division 2 malocclusions.

retrognathic A mandible or maxilla that is retruded or backward relative to other facial structures.

retrognathism is usually due to a size discrepancy (jaw too short) or positional abnormality (jaw too far back). Retrognathism is often is the result of jaw growth deficiency.

retrusive, retruded, or recumbent. A term used when the front teeth are slanted toward the tongue (lingually) or back of the mouth. Retrusion is characterized by anterior teeth or jaws that are distal or posterior to their normal positions. This may occur with retraction mechanics including headgear wear, extraction site closure, or Class II elastic mechanics.

root That part of the tooth not covered by enamel, normally lying within the alveolus where it is attached to the bone by the periodontal membrane or ligament.

root canal A procedure where the nerve and blood vessels of a heavily decayed tooth are removed from the tooth and replaced with a filling material.

root movement Tip, torque, or translation of the root through supporting alveolar bone by resorption of bone in the frontal path of movement and bone deposition in the wake.

root resorption The dissolution or breakdown of part of the root of a tooth. Root resorption may originate within the root or externally. Root resorption is said to be idiopathic when its cause is unknown.

rotation Though rotation can occur around any axis, orthodontic rotation usually refers to the turning of a tooth by movement around its long axis. A tooth is said to be rotated if turning it around its long axis is required to bring it to its proper position.

sagittal plane Of, relating to, situated in, or being the median plane of the body or any plane parallel to it. In dentistry, the midsagittal plane is the median plane that divides the mouth into right and left halves.

separation An orthodontic procedure for slightly separating teeth to facilitate placing bands.

separator A device inserted between the crowns of teeth which are to be fitted with orthodontic bands.

separators are usually made of elastomeric material or small metal springs. Separators will push the teeth slightly apart so that the band material passes freely between the teeth.

serial extraction A program of selective or guided extraction of primary and sometimes permanent teeth over a period of time, with the objective of relieving crowding and facilitating the eruption of remaining teeth into improved positions.

skeletal malocclusion A malocclusion characterized by deviations from the normal size, shape, or position of craniofacial bones. There usually is a concomitant dental malocclusion. Skeletal malocclusions generally require both skeletal and dental corrections for optimum dental and facial esthetics.

slot, bracket That portion of a bracket which receives an arch wire. Edgewise bracket slots are rectangular in cross section. Either 0.018 x 0.025 or 0.022 x 0.028 inches in dimension with the shorter dimension open go the buccal or labial.

soft palate See palate.

space maintainer A prosthetic replacement for prematurely lost primary teeth intended to prevent closure of the space before eruption of the permanent successors. Often an urgent necessity in the buccal segment to prevent impaction of the permanent teeth and other complications.

space regainer Correction of tooth displacement resulting from premature loss of one or more primary teeth without timely space maintenance. Effective when the space loss is recent and small. May be accomplished with varying types of corrective appliances. Often most efficiently accomplished as a part of a comprehensive orthodontic treatment plan.

spacing The sum of the mesiodistal widths of the teeth in an arch is less than the arch circumference.

specialist A practitioner who (a) has completed advanced specialty training in an accredited postdoctoral program, (b) has successfully completed specialty examination by the state, (c) has been granted a specialty license and (d) limits his/her practice to the diagnosis and treatment of diseases and conditions within the purview of the specialty.

Spee, curve of The occlusal and incisal surfaces of the tooth crowns in either dental arch describe a curve, from a lateral or sagittal view. The curve is concave upward with reference to the mandibular arch and convex for the maxillary arch. See curve of Spee.

splint A rigid appliance used to connect and mutually support teeth or bones. A removable form is often used to temporarily relieve occlusal interferences in functional disorders of the temporomandibular joint and related musculature.

stomatognathic system Literally, the mouth-jaw system; the entire complex of structures of the head and neck involved in the functions of mastication, swallowing, respiration and speech.

stop A bend or auxiliary attachment placed on a wire to limit the arch wire from sliding or moving in the molar tube or slot of an orthodontic bracket.

straight wire appliance A variation of the edgewise appliance in which brackets are pre-angulated (mesial-distal tip) and pre-torqued (buccal/labial-lingual torque), and have variable bracket slot off-sets to minimize multiple archwire bends. Brackets and molar tube slots are specifically orientated in three planes of space for each tooth in the mouth.

stripping Reproximating or slenderizing the mesiodistal widths of teeth. Stripping usually occurs in the anterior but posterior air rotor stripping may also be undertaken. See reproximation, slenderization, or interproximal reduction (IPR).

subdivision An Angle Class II or Class III malocclusion that is unilateral. The designation of the subdivision as right or left indicates the side which is Class II or Class III. Subdivision malocclusions can be due to dental shifts or eccentric jaw positions. The distinction requires differential diagnosis.

succedaneous teeth Those permanent teeth that replace or succeed the primary teeth, which includes all permanent teeth except the permanent molars.

super elastic Refers to a metallic alloy having a relatively substantial elastic range; within a specific range of temperatures, the elastic portion of the force-deformation relationship for the alloy has two distinct, sequential parts because of a submicroscopic metallurgic phase-change that occurs as the force-magnitude is increased; a reversal of the phase-change occurs as the magnitude of force is subsequently decreased toward the passive state.

supernumerary teeth Some people have extra teeth, i.e., teeth in excess of the normal number. These are called supernumerary teeth. Supernumerary teeth are often malformed or erupt abnormally.

suture In anatomy, a fibrous junction between bones. The line of union in an immovable articulation as between the bones of the skull.

syndrome A group of symptoms and/or deformities that occur together in a recognizable pattern, defining a specific disease or condition.

tartar Another name for calculus.

technique, appliance A method or procedure based on the use of certain appliances in specific ways. There are numerous variations and combinations.

temporomandibular joint articulation The bony articulation between the mandible and the right and left temporal bones to form the right and left temporomandibular joints.

tie wing The portion of a bracket which retains a ligature

TMD or temporomandibular dysfunction Abnormal function of the temporomandibular joints.

TMJ or temporomandibular joint TMJ is an abbreviation for the temporomandibular joint. The temporomandibular joint is the joint where the lower jaw connects to the skull. One of the two paired articulations between the temporal bones of the skull and the mandible; the condylar processes of the mandible articulate on the anterior slope of the glenoid fossae of the temporal bones.

therapeutic diagnosis An assessment of the objectives and available methods of treatment in light of known conditions existing in the individual patient. An empirical diagnosis by clinical trial. The response to therapy becomes a criterion in the ongoing diagnosis.

thumb (or finger) sucking A normal infantile activity sometimes extending into middle or late childhood. In certain situations, may produce or exacerbate malocclusion. The duration, frequency, and intensity of the habit determine the clinical significance of the habit.

tinnitus Hearing a ringing, buzzing, or roaring noise in the ear. A symptom often reported by patients with TMD. The sound is subjective, i.e., it is only head by the one affected.

tipping The tendency of a tooth to turn or rotate in either the mesiodistal or buccolingual direction when a force is applied to the crown. Tipping can change either the inclination or angulation of a tooth. Orthodontists frequently refer to mesial-distal tip and buccolingual or labiolingual torque

tipping, controlled The application of a force plus a moment to the crown which is designed to cause the tooth to rotate around a center that is at the root apex. The crown moves the greatest distance and the apex moves the least as the tooth tips.

tongue thrust Interposition of the tongue between the anterior teeth, especially in the initial stage of swallowing. This action, often combined with a resting position also between the teeth, can inhibit normal eruption and so produce an open bite.

tooth size discrepancy Lack of proportional harmony in the width (mesiodistal diameter) of various tooth crowns and the available space in the dental arch, causing relative spacing or crowding in different parts of the dentition.

torque A third order couple moving the crown in one direction and the root in the opposite direction. The term is commonly used to refer to forces that produce buccolingual or labiolingual rather than mesiodistal movements. With respect to the edgewise appliance, it is the force system created when a rectangular arch wire is engaged in a bracket slot in torsion, and which has the effect of changing the inclination of the tooth. Torque also refers to torsion or twisting bends deliberately placed in a rectangular arch wire which are intended to change the inclination of the tooth.

traction The act of drawing or pulling the teeth. Also used to describe a force delivery component of an appliance that is mechanically activated by elastically extending its characteristic length, e.g., as in the stretching of an elastic module or a coiled spring.

transitional dentition See dentition.

translation The movement of a body as a whole such that the displacements of all particles of that body are alike or equal in magnitude, direction, and sense. The angulation of the long axis must remain unchanged.All points on a tooth move in parallel straight lines. The center of rotation is at infinity. There are no tipping or rotating movements.

transposition Teeth which have switched positions in the dental arch.

transverse displacement An orthodontic tooth movement characterized by displacements of points of the tooth at right angles or perpendicular to the long-axis orientation.

trauma Tissue damage caused by an external force, such as a blow in an accident or abnormal clenching or grinding of the teeth.

twin block appliance A functional appliance developed by William Clark, with inclined planes on maxillary and mandibular components, to guide the mandible forward.

twin edgewise or Siamese bracket An edgewise bracket formed by two single edgewise tie wings side by side on one base. Two tie wings attached to the same base provides excellent control of rotations. This bracket was designed by Dr. Brainard (Barney) Swain, one of Dr. McAnnally’s mentors, and has been the mainstay of traditional orthodontics for decades.

underbite An ambiguous non-technical term for negative overjet now considered archaic.

universal appliance An orthodontic appliance developed by S.R. Atkinson, combining some of the principles of edgewise and ribbon arch appliances with very light arch wires.

uprighting Tipping inclined teeth to a more normal vertical axial inclination.

velopharyngeal insufficiency An anatomic or functional deficiency in the soft palate or superior pharyngeal constrictor muscle that prevents closure of the opening between the mouth and nose in speech. The result is a nasal speech quality and an open portal for food passage from the oropharynx to the nasopharynx above.

vertical dimension The vertical relationship of the mandible to the maxilla in the rest or occluded position.

vertical elastic traction Pertaining to forces occlusally directed and delivered through orthodontic attachments to tooth crowns as the result of the (stretching) activation of an ‘up-and-down’ elastic band.

wax bite A procedure to record how the teeth come together when you bite. You bite into a wax wafer. The orthodontist uses the bite marks in the wax wafer to relate the upper dental cast to the lower dental cast. The stone study models or casts of the teeth then give an accurate representation of the occlusion or how the teeth meet when you close normally.

wax, orthodontic A clear wax used to prevent the braces from irritating the lips when the braces are first put on, or at other times when you are experiencing irritation from the braces.

wear facet A flat, polished surface on a tooth produced by physiologic or parafunctional occlusal contact.

Wilson, curve of See curve of Wilson.

working side The lateral segment of the dentition toward which the mandible is moved during masticatory function.

x-bite This is an abbreviation for crossbite.

x-ray Electromagnetic radiation produced when electrons strike a target under high voltage in a vacuum. The term is sometimes used incorrectly as a synonym for radiograph