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29 Cards in this Set
- Front
- Back
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Functional mandibular movement
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characteristic movements of the mandible made during speech, mastication, yawning, swallowing, and other associated movements.
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Parafunctional mandibular movement
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Movements of the mandible that accomplish no purposeful objective and are potentially harmful such as clenching, grinding and bruxing
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What are the types of mandibular movements
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Rotation and Translation
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Rotation of Mandible
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Rotational movement of mandible with condyles in centric relation
Mandible moves up and down around the central axis of the condyles |
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Translation of Mandible
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Movement of the condylar disc anteriorly and inferiorly along the articular surface of the temporal bone
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What planes can the mandible move in?
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Horizontal plane
Frontal plane Sagittal plane |
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Movement of mandible on Horizontal/Transverse axis
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Movement in sagittal plane
Mandible makes rotational opening and closing around horizontal axis through both condyles |
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Movement of mandible on Frontal/Vertical axis
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Movement in horizontal plane
Mandible moves into lateral excursion Vertical axis extends through working side condyle |
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Movement of mandible on Sagittal axis
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Movement in frontal plane
When mandible moves to one side, the condyle on the side opposite to the direction of movement travels forward |
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Border position
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Extreme position of the mandible in any given direction
Ex Centric relation Lateral Protrusive |
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What is the most retruded border position?
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Centric relation
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Border movements
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Movement of the mandible through the outer range of motion (Connect the dots from the border position points)
Limited by ligaments and articular surfaces of the TMJ as well as teeth |
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What limits border movement
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Ligaments
Articular surfaces of TMJ Morphology and alignment of teeth |
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Superior contact border
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Centric relation (CR) position
Determined by occluding surfaces of the teeth initial tooth contact occurs between mesial incline of maxillary and distal incline of mandibular teeth Also Lingual incline of maxillary hits Labial incline of mandibular anterior teeth |
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Superior anterior shift
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Moves mandible from centric relation (CR) position to maximum intercuspation position
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Anterior opening border movement
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From the maximum protrusive movement reached by the jaw, the mandible is maximally opened
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Posterior opening border movement
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Two-stage hinge movement
1. Condyles are stabilized in most superior position in fossa 2. Mandible is lowered in pure rotational movement without translation of condyle. Anterior teeth are 20-25mm (12*) apart 3. Second stage of movement involves rotation and translation - mandible is opened to its maximum limit |
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Functional movement
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Chewing stroke
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Envelope of motion
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3-D space circumscribed by mandibular border movements within which all unstrained mandibular movement occurs
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Envelope of function
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3d space contained within the envelope of motion that defines mandibular movement during masticatory function or phonation
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Vertical dimension
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Refers to the length of the face
during rest position during occlusion |
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Vertical dimension of physiological rest position
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Vertical separation of jaws when the opening and closing muscles of mandible are at rest in minimum tonic contraction
Dimension remains fairly constant throughout life |
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Vertical dimension of occlusion
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Vertical separation of the jaws when the teeth are in occlusion
VD occlusion = VD rest - Interocclusal distance |
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Inter-occlusal space
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The distance/gap between upper and lower teeth when mandible is in physiological rest position
Usually 2-3mm at 1st PM area |
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Centric Relation
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Most retruded relation of the mandible to the maxilla when the condyles are in the most posterior, unrestrained position in the fossa
Position is independent of tooth contact |
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Terminal Hinge Position
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The position of the mandible from which pure hinge movement is possible
Maximum range is 12* Creates a range of 18-25mm of interincisal opening |
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What is the significance of centric relation
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It is a reference point when recording maxillomandibular relations
It can be verified and repeated It serves as a reference point during denture construction Itis the starting point for developing occlusion It is a functional position |
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What can be used as a reference point when recording maxillomandibular relations
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Centric Relation
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Face bow
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Used to record the relationship of the maxilla to the TMJ and to orient the casts in the same relationship measured
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