Intro to Occlusion 4

mandibular side shift

(mandibular translation)- 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—see also EARLY MANDIBULAR LATERAL TRANSLATION, IMMEDIATE MANDIBULAR LATERAL TRANSLATION, PROGRESSIVE MANDIBULAR LATERAL TRANSLATION

terminal hinge axis

(transverse horizontal axis)- an imaginary line around which the mandible may rotate within the sagittal plane

guidance

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3 Types of occlusion

1. Bilateral balanced occlusion 2. Unilateral balanced occlusion 3. Mutually protected occlusion

Name the 6 mandibular movements

1. Depression 2. Elevation 3. Retrusion 4. Protrusion 5. Right lateral excursion 6. Left lateral excursion See slides 34- 45 for pictures

Posterior determinants of occlusion

1. angle of the articular eminence 2. mandibular lateral translation

malocclusion

1: any deviation from a physiologically acceptable contact between the opposing dental arches 2: any deviation from a normal occlusion—see ANGLE′S CLASSIFICATION OF OCCLUSION

anterior guidance

1: the influence of the contacting surfaces of anterior teeth on tooth limiting mandibular movements 2: the influence of the contacting surfaces of the guide pin and anterior guide table on articulator movements

eccentric

Any position of the mandible other than that which is its normal position

Condylar guidance

Bear in mind that we're actually referring to the inclination of the articular eminence THE INCLINATION OF THE ARTICULAR EMINENCE "GUIDES" THE ACTIONS OF THE CONDYLE This setting controls the amount of separation between maxillary and mandibular molars when the patient protrudes the mandible.

Mutually protected occlusion

Centric relation = maximum intercuspation Six anterior maxillary teeth together with six anterior mandibular teeth guide excursive movements of the mandible. No posterior occlusal contact occur during any lateral or protrusive excursions

mandibular lateral translation

During translation, the mandible shifts bodily in the direction of the working side movement. Sometimes that movement is great, as in 1. Sometimes it is minimal as in 3.

What are the 3 axes of mandibular movement?

Horizontal axis Vertical axis Sagittal axis

excursion

In dentistry, the movement occurring when the mandible moves away from maximum intercuspation

Hanau's formula

L=H/8+12 L=lateral side shift setting H=condylar guidance setting This is the way we will set the lateral side shift settings on our articulators.

Rotation:

Movement of the condyles about the axis of rotation while remaining within the mandibular fossae

translation

Movement of the condyles out of the mandibular fossae

Notice what happens to the position of the condyle when opening with rotation only..

The condyle is in a superior, retruded position, but the condyles are rotated, still with the disc interposed

Notice what happens to the position of the condyle at rest

The condyle is in a superior, retruded position, with the disc interposed between the condyle and the fossa

Notice what happens to the position of the condyle when mouth is opened wide with rotation annd translation...

The condyle rotates and slides out of the glenoid fossa. The disc is brought along with the condyle

Bilateral balanced occlusion

The idea was to have as many contacts as possible in all positions, centric and excursive. only used in complete denture fabrication

Christensen's phenomenon

To make a protrusive interocclusal record wafer, start with a CR wafer, Use the material from the inside of the wafer to thicken the posterior portion of the wafer to accommodate Christensen's phenomenon.

capsule

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

centric relation

an anteriorly, superiorly braced position along the articular eminence of the glenoid fossa, with the articular disc interposed between the condyle and eminence.

pathogenic occlusion

an occlusal relationship capable of producing pathologic changes in the stomatognathic system

mutual protection

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

mandibular movement

any movement of the lower jaw

occlusal device

any removable artificial occlusal surface used for diagnosis or therapy affecting the relationship of the mandible to the maxillae. It may be used for occlusal stabilization, for treatment of temporomandibular disorders, or to prevent wear of the dentition

Horizontal axis

around the hinge axis of the mandible defined by the line connecting the centers of rotation of the two condyles.

Unilateral Balanced Occlusion

commonly known as group function Unilateral balanced occlusion calls for all teeth on the working side to be in contact during a lateral excursion. Teeth on the nonworking side are contoured to be free of any contact.

The Curve of Monson

curve of occlusion confroming to a segment of the surface of a sphere 8 inches in diameter

Posselt

describes the extremes of the mandibular movement in all directions. These extremes of motion are known as Posselt's envelope of motion. The extremes define what are known as border movements.

parafunction

disordered or perverted function

interference

in dentistry, any tooth contacts that interfere with or hinder harmonious mandibular movement

articular disk

interposed between the condyle and eminence

Bennett movement

lateral and backward movement of the condyle on the working side

border movement

mandibular movement at the limits dictated by anatomic structures, as viewed in a given plane

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

Curve of Wilson

seen from the frontal plane

Curve of Spee

seen from the sagittal plane.

disocclusion

separation of opposing teeth during eccentric (any position of the mandible other than that which is its normal position) movemets of the mandible

nonworking side

that side of the mandible that moves toward the median line in a lateral excursion. The condyle on that side is referred to as the nonworking side condyle

attrition

the act of wearing or grinding down by friction 2: the mechanical wear resulting from mastication or parafunction, limited to contacting surfaces of the teeth-comp ABRASION, EROSION

temporomandibular joint

the articulation between the temporal bone and the mandible. It is a bilateral diarthrodial, bilateral ginglymoid joint 2: the articulation of the condylar process of the mandible and the intraarticular disk with the mandibular fossa of the squamous portion of the temporal bone; a diarthroidal, sliding hinge (ginglymus) joint. Movement in the upper joint compartment is mostly translational, whereas that in the lower joint compartment is mostly rotational. The joint connects the mandibular condyle to the articular fossa of the temporal bone with the temporomandibular disk interposed

intercondylar distance

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

vertical overlap

the distance teeth lap over their antagonists as measured vertically; especially the distance the maxillary incisal edges extend below those of the mandibular teeth. It may also be used to describe the vertical relations of opposing cusps 2: the vertical relationship of the incisal edges of the maxillary incisors to the mandibular incisors when the teeth are in maximum intercuspation

Sagittal axis

the jaw also drops down when jaw executes a lateral excursion

bruxism

the parafunctional grinding of teeth 2: an oral habit consisting of involuntary rhythmic or spasmodic nonfunctional gnashing, grinding, or clenching of teeth, in other than chewing movements of the mandible, which may lead to occlusal trauma—called also tooth grinding, occlusal neurosis

clenching

the pressing and clamping of the jaws and teeth together frequently associated with acute nervous tension or physical effort

horizontal overlap

the projection of teeth beyond their antagonists in the horizontal plane

working side

the side toward which the mandible moves in a lateral excursion

speaking space

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

determinants of occlusion

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

Vertical axis

when the jaw executes a lateral excursion