REST 702 -- Definitions

frontal plane

any plane parallel with the long axis of the body and at right andgles to the median plane

horizontal plane

any plane passing through the body at right angles to both the median and frontal planes, thus dividing the body into upper and lower parts

sagittal plane

any vertical plane or section parallel to the median plane of the body that divides a body into right and left portions

angles class I -- normal occlusion or neutroocclusion (long definition)

dental relationship in which there is normal anteriposterior relationship of the jaws, as indicated by correct interdigitation of maxillary and mandibular molars, but with crowing and rotation of teeth elsewhere (i.e. dental dysplasia or arch length deficiency)

retrusion

movement toward the posterior

disocclusion

separation of opposing teeth during eccentric movements of the mandible

Angle's Class II Division I (long definition)

the dental relationship in which the mandibular dental arch is posterior to the maxillary dental arch in one or both lateral segments -- mandibular first molar is distal to the maxillary first molar for division II -- bilateral distal with a normal or square-shaped maxillary arch, retruded maxillary central incisors, labially malposed maxillary lateral incisors, and an excessive vertical overlap. Subdivisions include right or left (unilaterally distal with other characteristics the same).

intercondylar distance

the distance between the rotational centers of two condyles or their analogues

centric occlusion

the occlusion of opposing teeth when the mandible is in centric relation. This may or may not coincide with the maximal intercuspal position

Propioception

the reception of stimulation of sensory nerve terminals within the tissues of the body that give information concerning movements and the position of the body perception mediated by proprioceptors

excursion

1. a movement outward and back or from a mean position or axis. Also, the distance traversed 2. in dentistry, the movement occuring when the mandible moves away from maximum intercuspation

malocclusion

1. any deviation from a physiologically acceptable contact between the oppoing dental arches 2. any deviation from normal occlusion

physiologic rest position (PRP)

1. mandibular position assumed when the head is in an upright position and the involved muscles, particulary, the elevator and depressor groups, are in equilibrium in tonic contraction (and the condyles are in a neutral, unstrained position 2. the position assumed by the mandible when the attached muscles are in a state of tonic equilibrium. Usually noted when the head is help upright 3. postural position of the mandible when a person is resting comfortably in an upright position and the associated muscles are in a state of minimal contractual activity **usually multiple tests are important to identify the position

most open position (MO)

The mandibular position as recorded by the greatest measurement between the maxillary and mandibular incisors, as described in Posselt's envelope of motion.

vertical axis of the mandible

imaginary line around whcih the mandible may rotate through the horizontal plane

eccentric

1. not having the same center 2. deviating from a circular path 3. located elsewhere than at the geometric center 4. any position of the mandible other than that which is its normal position

interocclusal rest space

The difference between the vertical dimension of rest and the vertical dimension while in occlusion.

interocclusal distance

The distance between occluding surfaces of the maxillary and mandibular teeth when the mandible is in a specified position.

interarch space (distance)

The interridge distance; the vertical distance between the maxillary and mandibular dentate or edentate arches under specified conditions

canine protected articulation (aka canine guidance)

a form of mutually protected articulation in which the vertical and horizontal overlap of the canine teeth disengage the posterior teeth in the excursive movements of the mandible

mediotrusion

a movement of the condyle medially (NONWORKING SIDE)

protrusion

a position of the mandible anterior to centric relation

protrusive interocclusal record

a registration of the mandible in relation to the maxilla when both condyles are advanced in the temporal fossa

lateral interocclusal record

a registration of the positional relationship of opposing teeth or arches made in either a right or left lateral position of the mandible

interocclusal record

a registration of the positional relationship of the opposing teeth or arches a record of the positional relationship of the teeth or jaws to each other

centric relation record

a registration of the relationship of the maxilla to the mandible when the mandible is in centric relation. Registration may be obtained either intraorally or extraorally.

articular disk

a ring of fibrocartilage that separates the articular surfaces of a joint

Curve of Spee

aka ANTERIORPOSTERIOR CURVE anatomic curve established by the occlusal alignment of the teeth, as projected onto the median plane, beginning with the cusp tip of the mandibular canine and following the buccal cusp tips of the premolar and molar teeth (continuing through the anterior border of the mandibular ramus, ending with the anterior most portion of the mandibular condyle)

Bennett movement

aka LATEROTRUSION condylar movement on the working side in the horizontal plane may be used in conjunction with other terms describing condylar movement in other planes (i.e. laterodetrusion, lateroprotrusion, lateroretrusion, laterosurtrusion)

Curve of Wilson (shorter definition)

aka MEDIOLATERAL CURVE in the mandibular arch, that curve (as viewed from the frontal plane) which is convace and contacts the buccal and lingual cusp tips of the mandibular molars. in the maxillary arch, that curve which is convex and contacts the buccal and lingual cusp tips of the maxillary molars

Curve of Wilson (longer definition)

aka MEDIOLATERAL CURVE in the theory that occlusion should be spherical, the curvature of the cusps as projected on the frontal plane expressed in both arches; the curve in the lower arch being concave and the one in the upper arch being convex. The curvature in the lower arch is affected by an equal lingual inclination of the right and left molars so that the tip points of the corresponding cross-aligned cusps can be placed into the circumferences of a circle. Transverse cuspal curvature of the upper teeth is affected by the equal buccal inclinations of their long axes.

Horizontal axis of mandible

aka transverse axis imaginary line around which the mandible may rotate within the sagittal plane

sagittal axis

an imaginary anteroposterior line around which the mandible may rotate when viewed in the frontal plane

terminal hinge axis (transverse horizontal axis)

an imaginary line around which the mandible may rotate within the sagittal plane

mutual protected articulation (aka mutually protected occlusion)

an occlusal scheme in which the posterior teeth prevent excessive contact of the anterior teeth in maximum intercuspation, and the anterior teeth disengage the posterior teeth in all mandibular excursive movements.

Class II is also referred to as ______________________

distocclusion

curve of Monson

eponym for a proposed ideal curve of occlusion in which each cusp and incisal edge touches or conforms to a segment of the surface of a sphere 8 inches in diameter with its center in the region of the glabella Monson GS occlusion as applied to crown and bridgework

laterotrusion

lateral and downward movement of the condyle on the WORKING SIDE

Angle's Class I

maxillary canine distal to mandibular canine (mx teeth are wider than mn teeth) MB cusp of max 1st molar lies in buccal groover on mand 1st molar

Angles Class II

maxillary canine mesial to mandibular canine MB cusp of max 1st molar lies anterior to the buccal groove on the mand. 1st molar

Angle's class III

maxillary canine much more distal to mandibular canine (like a whole tooth width) MB cusp of max 1st molar lies distal to the buccal groove on the mand. 1st molar

Class III is also referred to as ___________________________

mesioocclusion

group function

multiple contact relations between the maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces

translation

that motion of a rigid body in which a straight line passing through any two points always remains parallel to its initial position. The motion may be described as a sliding or gliding motion

maximal intercuspal position (MIP)

the complete intercuspation of the opposing teeth independent of condylar position, sometimes referred to as the best fit of the teeth regardless of the condylar position also called maximal intercuspation

Angle's Class III (long definition)

the dental relationship in which the mandibular arch is anterior to the maxillary arch in one or both lateral segments; the mandibular first molar is mesial to the maxillary first molar. The mandibular incisors are usually in anterior cross bit. Subdivisions include right or left (unilaterally mesial with other characteristics the same).

Angle's Class II Division I (long definition)

the dental relationship in which the mandibular dental arch is posterior to the maxillary dental arch in one or both lateral segments -- mandibular first molar is distal to the maxillary first molar for division I -- bilateral distal retrusion with a narrow maxillary arch and protruding maxillary incisors. Subdivisions include right or left (unilaterally distal with other characteristics being the same)

occlusal vertical dimension

the distance measured between two points when the occluding members are in contact

articular capsule

the fibrous ligament that encloses a joint and limits its motion. It is lined with the synovial membrane

speaking space

the space that occurs between the incisal or/and occlusal surfaces of the maxillary and mandibular teeth during speech

mandibular translation (side shift)

the translatory (medio-lateral) movement of the mandible when viewed in the frontal plane. While this has not been demonstrated to occur as an immediate horizontal movement when viewed in the frontal plane, it could theoretically occur in an essentially pure translatory form in the early part of the motion or in combination with rotation in the latter part of the motion or both

determinants of mandibular movement

those anatomic structures that dictate or limit the movements of the mandible. The anterior determinant of mandibular movement is the dental articulation. The posterior determinants of mandibular movement are the temporomandibular articulations and their associated structures.