Orthodontic Terms Flashcards
Anchorage
The source of resistance to the forces generated in reaction to the active components of an appliance.
Angulation
Degree of tip of a tooth in the mesiodistal plane
Anterior Open bite
There is no vertical overlap of the incisors when the buccal segment teeth are in occlusion.
Balancing extraction
Extraction of the same (or adjacent) teeth on the opposite side of the arch to preserve asymmetry
Bimaxillary proclination
Both upper and lower incisors are proclined relative to the skeletal bases
Bimaxillary retroclination
Both upper and lower incisors are retroclined relative to the skeletal bases
Bodily movement
Equal movement of the root apex and crown of a tooth in the same direction
Buccal crossbite
The buccal cusps of the lower premolars and/or molars occlude buccally to the buccal cusps of the upper premolars and/or molars
Centric occlusion
Position of maximum interdigitation
Centric relation
The condyle is in its most superior anterior position in the glenoid fossa
Cingulum plateau
The convexity of the cervical third of the lingual/ palatal aspect of the incisor and canines
Compensating extraction
Extraction of the same tooth in the opposing arch
Competent lips
Upper and lower lips contact without muscular activity at rest
Complete overbite
The lower incisors occlude with the upper incisors or palatal mucosa
Crowding
Where there is insufficient space to accomodate the teeth in perfect alignment in an arch, or segment of an arch
Curve of Spee
Curvature of the occlusal plane in the sagittal plane
Dento-alveolar compensation
The inclination of the teeth compensates for the underlying skeletal pattern, so that the occlusal relationship between the arches is less marked
Hypodontia
This term is used when one or more pemanent teeth (excluding third molars) are congenitally absent.
Ideal occlusion
Anatomically perfect arrangement of the teeth. Rare.
Andrew desrcibed the “six keys to an ideal occlusion”
Impaction
Impeded tooth eruption, usually because of displacement of the tooth or mechanical obstruction, eg crowding or a supernumerary tooth
Inclination
Degree of tip of a tooth in the labiopalatal plane
Incompetent lips
Some muscular activity is required for the lips to meet together
Incomplete overbite
The lower incisors do not occlude with the opposing upper incisors or the palatal mucosa when the buccal segment teeth are in occlusion
Intermaxillary
Between the arches
Intramaxillary
Within the same arch
Leeway space
The difference in diameter between the deciduous canine, first molar, and second molar and ther permanent successors (canine, first premolar, and second premolar)
Lingual crossbite
The buccal cusps of the lower premolars and/or molars occude lingually to the lingual cusps of the upper premolars or molars. Sometimes referred to as a scissors bite
Malocclusion
Variation from ideal occlusion which has dental health and/or psychosocial implications for the individual.
NB The borderline between normal occlusion and malocclusion is contentious
Mandibular deviation
The path of closure of the mandible starts from a postured position
Mandibular displacement
When closing from the rest position, the mandible displaces (either laterally or anteriorly) to avoid a premature contact.
The premature contact can be determined by placing the mandible into the retruded contact position (centric relation)
Midline diastema
A space between the central incisors.
Most common in the upper arch.
Normal occlusion
Acceptable variation from ideal occlusion
Overbite
Vertical overlap of the upper and lower incisors when viewed anteriorly.
Overjet
Distance between the upper and lower incisors in the horizontal plane.
Normal overjet is 2-3 mm
Posterior open bite
When the teeth are in occlusion, there is a space between the posterior teeh
Relapse
The return, following correction, of features of the original malocclusion
Reverse overjet
The lower incisors lie anterior to the upper incisors.
When only one or two incisors are involved, the term anterior crossbite is commonly used
Rotation
A tooth is twisted around its long axis
Spacing
Where the teeth do not touch interproximally and there are gaps between adjacent teeth.Can be localized or generalized.
Tipping movements
Movement of the rooth apex and crown in opposite directions around a fulcrum
Torque
Movement of the root apex buccolingually, either with no or minimal movement of the crown in the same direction
Traumatic overbite
The occlusion of the lower incisors with the palatal mucosa has led to ulceration. It is also possible to have ulceration of the labial mucosa of the lower incisors due to the upper incisor’s occlusion.
