Occlusion Midterm

Front 1

Maximal Intercuspal Position

Back 1

The complete intercuspation of the opposing teeth independent of condylar position

Front 2

Centric Occlusion

Back 2

The occlusion of opposing teeth when the mandible is in central relation.

This may or may not coincide with the maximal

intercuspal position.

Front 3

Centric Relation

Back 3

The maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the shapes of the articular eminencies.

> This position is independent of tooth contact.
> This position is clinically discernible when the mandible is directed superior and anteriorly. It is restricted to a purely rotary movementabout the transverse horizontal axis.

Front 4

Centric Position

Back 4

The position of the mandible when the jaws are in centric relation

Front 5

Retruded Contact Position

Back 5

Guided occlusal relationship occurring at the most retruded position of the condyles in the joint cavities.

A position that may be more retruded then the centric relation position.

Front 6

Postural Position

Back 6

Any mandibular relationship occurring during minimal muscle contraction.

Front 7

Occlusal Vertical Dimension

Back 7

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

Front 8

Rest Vertical Dimension

Back 8

The distance between two selected points (one of which is on the middle of the face or nose and the other of which is on the lower face or chin) measured when the mandible is in the physiologic rest position

Front 9

Physiologic Rest Positon

Back 9

The mandibular position assumed when the head is in an upright position and the involved muscles, particularly the elevator and depressor groups, are inequilibrium in tonic contraction, and the condyles are in a neutral, unstrained position

Front 10

Interocclusal Distance

Back 10

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

Front 11

Interocclusal Rest Space

Back 11

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

Front 12

Hinge Movement (rotation)

Back 12

The movement in space characterized by two divergent points moving around a central axis of rotation

Front 13

Transverse Horizontal Axis (hinge axis)

Back 13

An imaginary line around which the mandiblemay rotate within the sagittal plane.

Front 14

Translatory Movements

Back 14

The movement in space characterized by linear motion with no axis of rotation

Front 15

Border Movements

Back 15

The most extreme positions to which the mandible is able to move – generally considered to be relatively stable and reproducible (not pathological). These movements have been described from the frontal, sagittal and horizontal planes.

Front 16

Posselt Diagram of Border Movements

Back 16

Describe border movements in three planes – sagittal, horizontal and frontal .

When combined describe a 3D envelope of motion that represents the maximum range of movement of the mandible.

Although this envelope of motion is characteristic in shape, it varies from individual to individual. It must be remembered this is a tracing of the movements of the mandibular incisal point movements.

Front 17

Working Side

Back 17

The side toward which the mandible moves during lateral excursion.

Front 18

Non-Working Side

Back 18

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

Front 19

Balanced Articulation/Occlusion

Back 19

The bilateral, simultaneous, anterior, and posterior occlusal contact of teeth incentric and eccentric positions. APPLIES ONLY WHEN REFERRING TO COMPLETE UPPER AND LOWER DENTURES.

Front 20

Mutually Protected Articulation/Occlusion

Back 20

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

Front 21

Anterior Guidance

Back 21

The influence of the contacting surfaces of anterior teeth on tooth limiting mandibular movements.

Edge of mandibular teeth sliding along the lingual aspect of maxillary teeth when in maximal intercuspal position.

AVG is 1-3 mm in both vertical and horizontal direction.

Front 22

Group Function

Back 22

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

Front 23

Protrusion

Back 23

A position of the mandible anterior to centric relation

Front 24

Protrusive Movement

Back 24

Mandibular movement anterior to centric relation

Front 25

Lateral Excursion

Back 25

Sideward movement of the mandible characterized by:

(1) Rotation of the working side condyle

(2) Forward, inward and downward translation of the non-working condyle

Front 26

Laterotrusion

Back 26

Movement of the working side condyle in the horizontal plane. May or may not be used in combination to describe other direction movements (i.e. lateroprotrusion, lateroretrusion, etc)

Front 27

Laterodetrusion

Back 27

lateral and downward movement of the condyle on the working side

Front 28

Lateroprotrusion

Back 28

lateral and forward movement of the condyle on the working side

Front 29

Lateroretrusion

Back 29

lateral and backward movement of the condyle on the working side

Front 30

Laterosurtrusion

Back 30

lateral and upward movement of the condyle on the working side

Front 31

Mediotrusion

Back 31

A movement of the condyle medially

Front 32

Bennet Movement

Back 32

Bodily shift of the mandible toward the working side during lateral excursion.

Movement caused by restraint from TMJ ligaments and medial wall of glenoid fossa on the non-working side.

Avg lateral mvmt is 0.75 mm

Front 33

Bennet Angle

Back 33

The angle formed between the anterior and medial movement of the non-working condyle and the straight protrusive path (s. Related to the degree of Bennet Movement.

Front 34

Functional Movement

Back 34

Chewing, swallowing, talking, etc. – all within the confines of the envelope of motion

Front 35

Occlusocranial Relationships

Back 35

Source Plane to

Mid-Sagital Plane >>> 60"

Mid-Sagital Plane to

Film Plane >>> 15"

Front 36

Porion (Po)

Back 36

Midpoint of the upper contour of the external auditory meatus

Front 37

Sella (S)

Back 37

Midpoint of the cavity of sella turcica

Front 38

Orbitale (O)

Back 38

The lowest point of the inferior margin of the orbit

Front 39

Pogonion (Pog)

Back 39

The most anterior point of the contour of the chin

Front 40

Menton (Me)

Back 40

Most inferior point on the mandibular symphysis

Front 41

Gnathion (Gn)

Back 41

The center of the inferior contour of the chin

Front 42

Gonion (Go)

Back 42

The center of

the inferior

contour of the

mandibular angle.

Front 43

Nasion (N)

Back 43

The anterior point

of intersection of

the frontal bone

and nasal bone

Front 44

Frankfort Horizontal Plane

Back 44

Porion (Po) to

Orbitale (O)

Front 45

Occlusal Plane

Back 45

Line bisecting the

overlapping cusps

of the first molars

and incisors

Front 46

CANT of the Occlusal Plane

Back 46

Angle formed between the occlusal plane

and Frankfort plane.

Mean Angle

9.3 degrees

Front 47

Facial Plane

Back 47

Nasion (N) to

Pogonion (Po)

Front 48

Facial Angle

Back 48

Frankfort-Facial

Angle.

Indicates degree of

protrusion or retrusion of the mandible.

Mean Angle

87.7 degrees

Front 49

Axis Orbital Plane

Back 49

Plane established by

Orbitale (O) and the

terminal hinge axis

Front 50

Mandibular Plane

Back 50

Menton (Me) to

Gonion (Go)

Front 51

Frankfort-Mandibular Angle

Back 51

Angle between

FH plane and

mandibular plane.

Mean Angle

21.9 degrees

Front 52

Y (Growth) Axis

Back 52

Sella (S) to

Gnathion (Gn)

Front 53

Frankfort - Y axis Angle

Back 53

Indicates the

position of

the chin

Mean Angle

59.4 degrees

Front 54

Inter-Incisor Angle

Back 54

Angle formed by

long axis of

the upper and

lower incisors.

Mean Angle

135 degrees

Front 55

Occlusal Plane - Maxillary Central Incisor Angle

Back 55

60 degrees

Front 56

Occlusal Plane - Mandibular Central Incisor Angle

Back 56

75 degrees

Front 57

Curve of Spee

Back 57

The anterior-posterior curve from the cusp tip of the mandibular canine following through the cusp tips of the posterior teeth

Front 58

Curve of Wilson

Back 58

The medio-lateral curve that contacts buccal and lingual cusps of the molars.

Lower in the middle due to the lingual inclination of the long axis of mandibular molars.

Front 59

Compensating Curve

Back 59

Combination of the Curve of Wilson and Curve of Spee.

Used to develop balanced occlusion.

Front 60

Angle's Classification of Occlusion

Back 60

Classification system of occlusion based on the interdigitation of the 1st molars.

Front 61

Angle's Class 1

Back 61

NEUTRAL OCCLUSION

The maxillary mesiobuccal cusp aligns with the mandibular mesiobuccal groove.

Front 62

Angle's Class 2

Back 62

ANTERIOR DISPLACEMENT

The maxillary mesiobuccal cusp lies anteriorly to the mandibular mesiobuccal groove.

Front 63

Class II Division I

Back 63

When Maxillary Anterior Teeth are PROCLINED and a large OVERJET is present

Front 64

Class II Division II

Back 64

When Maxillary Anterior Teeth are RETROINCLINED and a deep OVERBITE exists

Front 65

Angle's Class 3

Back 65

POSTERIOR DISPLACEMENT

The maxillary mesiobuccal cusp lies posteriorly to the mandibular mesiobuccal groove.

Front 66

Occlusal Table

Back 66

"Inner Incline" of the cusps.

50-60% of the total BL width

Front 67

Supporting Cusps

Back 67

OCCLUDING CUSPS (1 mm of contact)

MAXILLARY LINGUAL & MANDIBULAR BUCCAL

• rounder
• hold the vertical dimension
• further from outer aspect
• LARGER outer incline seen from occlusion

FUNCTIONAL OUTER ASPECT: outer incline that participates in occlusion

Front 68

Guiding Cusps

Back 68

Cusps that do not occlude.

MAXILLARY BUCCAL & MANDIBULAR LINGUAL

• sharper
• closer to outer aspect
• SMALLER outer incline seen from occlusion

Front 69

Crown Forms

Back 69

BUCCAL-LINGUAL [FRONTAL]

> All Teeth: TRAPEZOID

MESIAL-DISTAL [PROXIMAL]

> Anterior: TRIANGULAR

> Post. Max: TRAPEZOID

> Post. Man: RHOMBOID

Front 70

Height of Contour

Back 70

Facial:

> All teeth: cervical 1/3

Lingual:

> Anteriors: Cervical 1/3

> Post Max: Middle 1/3

> Post Man: Occlusal 1/3

Front 71

Over or Under Contouring

Back 71

Important for the movement of food away from gingival crevices.

Front 72

Cervical Line Form

Back 72

The way the CEJ faces.

Flatten as you move posteriorly. [depth decreases]

F/L DIRECTED TOWARD THE APEX

• U shaped

M/D DIRECTED TOWARD THE CROWN

• inverted U shape
• Mesial more curved than distal on same tooth
• adjacent teeth will have similar curvatures

Front 73

Contact Height

Back 73

HIGHER ON THE MESIAL THAN THE DISTAL.

CONTACT GETS CLOSER TO THE GINGIVA AS YOU MOVE POSTERIORLY

Front 74

Contact Point/Embrasures

Back 74

Anterior Teeth: contact divides the tooth equally (B & L embrasures are equal)

Posterior Teeth: contact occurs more buccally (lingual embrasure larger than buccal embrasure)

Front 75

Axial Positions

Back 75

Mandibular 3rd Molars = largest root inclination [BUCCAL}

Maxillary Central Incisors = 2nd largest root inclination [LINGUAL]

Maxillary 2nd Premolars = most vertical tooth

Mandibular 3rd Molars = tilt mesially & lingually

Front 76

Maxillary Axillary Positions: Lateral View

Back 76

Note that the anteriors are mesially inclined while the most posterior teeth become more distally inclined with reference to the alveolar bone.

Front 77

Maxillary Axillary Positions: Frontal View

Back 77

Note that all the posteriors are

slightly inclined bucally.

Posterior roots incline palatally except for DB root of 1st molar

Front 78

Root Inclination: Maxillary Incisors

Back 78

AXIAL: MESIAL INCLINATION

Central Incisors = 2 degrees

Lateral Incisors = 7 degrees

SAGITAL: LINGUAL INCLINATION

Central Incisors = 28 degrees

Lateral Incisors = 26 degrees

Front 79

Root Inclination: Maxillary Canines

Back 79

AXIAL: DISTAL INCLINATION

Canines = 17 degrees

SAGITTAL: LINGUAL INCLINATION

Canines = 16 degrees

Front 80

Mandibular Axial Positons: Lateral View

Back 80

Note that both the anteriors and posteriors are inclined mesially.

Front 81

Mandibular Axial Positions: Frontal View

Back 81

Note that all the posteriors are slightly inclined lingually (with roots inclined buccally).

Front 82

ONLY MANDIBULAR TOOTH WITH LINGUAL INCLINATION TO THE ROOT APEX

Back 82

1st PREMOLAR

Front 83

Horizontal & Vertical Overlap

Back 83

Front 84

Overlap and Anterior Guidance

Back 84

Anterior Guidance INCREASES when:

INCREASE VERTICAL OVERLAP

DECREASE HORIZONTAL OVERLAP

Front 85

Occlusal Lines

Back 85

BO line: mandibular buccal cusps

LO line = maxillary lingual cusps

CF line = central fossa

BO-CF line = mandibular buccal and maxillary CF

LO-CF line = maxillary lingual and mandibular CF

Front 86

In maximal intercuspal position which teeth

occlude with only one opposing tooth?

Back 86

Mandibular Central Incisors

Maxillary 3rd molars

Front 87

Working Side Condyle

Back 87

Rotating Condyle during lateral excursion.

Front 88

Non-woking Side Condyle

Back 88

Moves toward median line in lateral excursion.

Moves Inward, downward, and forward.

Front 89

Canine Protected Guidance

Back 89

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.

Canines force posterior teeth to disengage during lateral excursion.

Front 90

Mutually Protected Articulation

Back 90

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

Front 91

Major Functions Related to Teeth

Back 91

• mastication
  
• speech
• esthetics

Front 92

What kind of joint is the TMJ?

Back 92

COMPOUND JOINT (condylar process, articular fossa, and articular disc)

also a synovial joint.

Front 93

2 Joints of the TMJ

Back 93

Upper and Lower joint cavities formed by the articular disc.

Lower Joint: hinge (ginglymoid joint)

Upper Joint: hinge and gliding (ginglymoathroidal joint)

Front 94

TMJ Evolution

Back 94

TMJ is a mammalian 'invention'.

Vertebrates before mammals formed jaw joint via endochondral bone formation and other portions of jaw via membraneous formation.

Immediate mammalian ancestors began forming a second jaw articulation between two bones (mandible and squamous part of temporal bone) developed via membraneous ossification. This new TMJ became dominant, and the endochondral jaw articulation shifted into the middle ear to become the malleus and incus.

Front 95

TMJ Embryology

Back 95

TMJ forms between 7th-11th weeks. TMJ malformation caused by teratogens acting during the first trimester.

Mesenchymal Formation. Either (1) single mesenchymal formation that differentiates into temporal and mandibular portions or (2) two initially independent mesenchymal condensations termed a temporal blastema and condylar blastema that grow towards each other but remain seperated by other mesenchymal tissue- the tendon of the lateral pterygoid- that becomes trapped between the two bones and separates to form the articular disc.

Front 96

Meckel's Cartilage

Back 96

1st pharyngeal arch cartilage that plays indirect role in TMJ formation- acts as central point around which membraneous formation of the mandible occurs.

Thus all parts of the mandible are formed around Meckel's cartilage, which ultimately transforms into the sphenomandibular ligament, anterior ligament of the malleus, and the malleus.

Front 97

Development of the TMJ

Back 97

Condyle development is secondary cartilage (originates with-in local mesenchymal blastema). This secondary cartilage persists and is gradually replaced by bone until age 17.

Front 98

Mandibular Condyle

Back 98

Surface is usually roughened and convex with an ellipsoid shape. The medial pole juts out significantly more than the lateral pole. The long axis of the condylar head is perpendicular to the posteriorly divergent ramus- forming an angle of about 145-160 degrees projecting toward the anterior rim of the foramen magnum (therefore, TMJ radiographs must be taken from an oblique perspective).

Front 99

Pterygoid Fovea

Back 99

Shallow cavity located on the anteriomedial aspect of the mandibular neck- where all fibers of the inferior head and most fibers of the superior head attach to the mandible.

Front 100

Blood supply to the condyle

Back 100

Inferior alveolar vessels

Front 101

In centric occlusion, the articular surface of the condyles face..

Back 101

the posterior slope of the articular eminence (and not the mandibular fossa)

Front 102

Squamous part of the temporal bone

Back 102

Forms the mandibular (glenoid) fossa, which is bound anteriorly by the posterior slope of the articular eminence and posteriorly by the postglenoid tubercle. The roof of the fossa is very thin compact bone with no underlying spongy bone and lined by very thin dense fibrous CT (implies joint is non-weight bearing)

It sits anteriorly to the petrotympanic fissure which the chorda tympani and anterior tympanic vessels pass through (not located in TMJ).

Front 103

Articular Disc Attachments

Back 103

Biconcave oval structure interposed between the articular surfaces of the TMJ dividing it into inferior and superior joint spaces. It is attach to the condyle at its medial and lateral poles. Posteriorly it is attached to the tympanic plate via the superior retrodiscal lamina and to the mandible via the inferior retrodiscal lamina. Anterior, superior, and inferior attachments are the the articular capsule.

Front 104

Articular Disc Anatomy

Back 104

Anterior, Intermediate, and Posterior portions. Posterior is the thickest, Intermediate is the thinnest. Posterior disc in continuous with the highly vascularized and innervated retrodiscal pad.

Frontal Cut >> medial portion thicker than the lateral portion

Front 105

Articular Capsule

Back 105

Disc merges with joint capsule around its periphery. Firmly attached anteriorly but not medially or laterally.

It acts to resist and medial, lateral, or inferior forces. It is highly innervated and thus provides proprioreceptive feedback.

Front 106

Temperomandibular Ligament

Back 106

Attaches to the articular capsule laterally providing stability in the posterior-lateral directions.

superficial oblique fibers (restrict lateral movement)

deep horizontal fibers (limit posterior movement).

Front 107

Accessory Ligaments

Back 107

NOT DIRECTLY PART OF THE TMJ BUT PLAY A ROLE IN GUIDING IT.

Sphenomandibular ligament attaches to the lingula of the ramus and sphine of sphenoid bone.

Stylomandibular ligament attaches to angle of mandible and styloid process. Limits protrusive mvmt.

Front 108

Blood and Nerve Supply

Back 108

Blood supply is via branches of the superficial temporal a. and maxillary a.

Nerve supply is via the auriculotemporal n. (sensory) with additional branches from nerves supplying muscles of mastication also playing a role in proprioception.

Referred pain from the TMJ is frequently to the ear (auriculotemporal n. innervates anterior part of the external auditory meatus)

Front 109

Movements Affecting the Articular Disc

Back 109

When lateral pterygoid m. contracts to open the jaw it pulls the disc downward & forward along the posterior slope (articular eminence.)

Open the jaw a little : bone contact with thick posterior part of the disc.

Open the jaw more : bone contact with thick anterior part of the disc.

Front 110

Biomechanics of the TMJ: 2 structurally and

functionally distinct systems

Back 110

(1) Tissues that surround the inferior synovial cavity (condyle and disc). Disc is tightly bound to condyle by the lateral and medial discal ligaments. Responsible for rotation.

(2) Composed of condyle-disc complex functioning against the surface of the mandibular fossa. Because the disc isn't tightly attached to the articular fossa, free sliding movement of the superior portion of the disc and mandibular fossa is possible in the superior cavity. This movement occurs when the mandible is moved anteriorly (translation).

Front 111

TMJ Stability

Back 111

TMJ stability is maintained by the constant activity of the muscles of mastication that pull across the joint.

• lateral ligament prevents anterior/posterior displacement, and with corresponding ligament of the opposite side prevents lateral dislocation.
• Capsule of the joint is weak anteriorly (most common direction of dislocation).

Front 112

Excessive Condylar Movement During Opening

Back 112

During wide yawn or large bite contractions of the lateral pterygoids may pull head of mandible excessive far anteriorly of the convexity of the articular eminence into the temporal fossa. Mandible is protruded and remains fixed in the open position. Muscle of mastication tend to go into spasm. Reduction of this dislocation is achieved by pressing downward and backward on the lower molar teeth.

Front 113

Parotid Gland and TMJ

Back 113

Parotid gland divided by facial n. into superficial and deep lobes. The deep lobe is wedged between the mastoid process and TMJ.

We avoid impinging it during wide jaw opening through anterior translation.

Front 114

Synovial Fluid Functions

Back 114

(1) Provides Lubrication: has viscous, egg-white consistency due to hyalouronic acid secreted by synovial membrane cells. When portion of articular cartilage is compressed it squeezes out fluid that reduces friction.

(2) Nourishes the Chondrocytes: normal amount of fluid is very small and must be continually circulated to provide nutrients and waste disposal. Circulates with joint movement and contains phagocytes.

(3) Shock Absorber: cushions shocks in the joints subject to compression. When pressure increases it absorbs shock and distributes it evenly across articular surfaces.

Front 115

Types of Cartilage

Back 115

(1) Hyaline Cartilage is very spongy making it ideal for compressive forces but susceptible to tearing with friction forces

(2) Elastic Cartilage is flexible and snaps back into place but not strong enough for the TMJ

(3) FIbrocartilage contains chondrocytes surrounded by tons of collagenous tissue making it ideal for with-standing frictional forces

Front 116

Histology of the TMJ: Articular Cartilage

Back 116

Fibrocartilage (not hyaline) covers articular surfaces. Varies in thickness so that it is thicker in locations where bones rub frequently (i.e. condylar eminence) but thinner where we don't need it.

Front 117

Histology of the TMJ: Temporal Bone

Back 117

Mandibular Fossa is formed by thin, translucent part compact bone covered by thin dense fibrous CT (no underlying diploic bone or fibrocartilage cover).

Articular Eminence is comprised of thick posterior slope and summit. This area has fibrocartilage arranged in two layers: an outer layer with CT fibers arranged in parallel to the bone surface and an inner later with CT fibers perpendicular to the bony surface.

Front 118

Histology of the Articular Disc: Anterior Band

Back 118

Smooth surfaces that minimize effects of friction. Anterior band is very vascular and lined by synovial membrane on both sides. It's fibers (collagen/elastin) are oriented anterior-posteriorly and its medial portion is very thick due to tendon of the superior head of lateral pterygoid.

Front 119

Histology of the Articular Disc: Intermediate Zone

Back 119

Avascular and not innervated. Consists of fine elastin and collagen fibers oriented anterior-posteriorly.

Front 120

Histology of the Articular Disc: Posterior Band

Back 120

Divided into Posterio-inferior and Posterio-superior lamina that surround the retrodiscal pad- which is highly vascular, innervated loose CT lined by synovial membranes on its inferior and superior sides.

The posterio-inferior lamina is composed of almost entirely collagenous fibers.

The posterio-superior lamina is composed of elastic fibers.

Both are arrange in an antero-posterior directions.

Front 121

Why are posterior lamina composed of different types of fibers?

Back 121

Condyle and disc displace when jaw opens.

Posterior-Superior band has to stretch a ton as it goes from almost vertical to horizontal. Requires elasticity >>> elastin fibers.

Posterior-Inferior band doesn't displace much but does have to endure some compressive forces >>> collagen fibers.

Front 122

Histology of the Mandibular Condyle:

3 distinct layers covering the superior aspect

Back 122

(1) fibrous articular layer (thick avascular fibrocartilage covering that obscures and smooths bone irregularities. Uniform thickness except in area of contact between condyle and eminence that is compressed during superior joint movement and hence thinner)

(2) cellular proliferative layer (6-10 cells thick containing undifferentiated mesenchymal cells w/ potential to form chondroblasts)

(3) layer of hyaline growth cartilage (can be divided into an outer zone of matrix formation, middle zone characterized by cellular hypertrophy, and inner zone of calcification and resorption)

Front 123

Histology of the Mandibular Condyle: Bone Type and Formation

Back 123

(1) Primary Cartilage Growth Site exhibits interstitial growth where chondrocytes of primary cartilage eventually degenerate and die.

(2) Condylar Cartilage exhibits appositional growth from cells produced in the intermediate cellular proliferative layer and cells in condylar cartilage emerge still living at the ossification front

Bone marrow of the condyle is hematopoetic type with trabeculae joining compact bone surface at right angles.

Posterior-Superior aspect is very vascular.

Front 124

Histology of the Articular Capsule

Back 124

Composed of two layers:

(1) Outer fibrous capsule termed stratum fibrosum.

(2) adjacent to joint spaces is the stratum synovia made up of loosely arranged bundlews and then walled fluid filled spaces

Front 125

Histology of the Synovial Membrane: Structure

Back 125

Specialized tissue lining all internal joint surfaces except for the articular surfaces and the disc. It lines the inner surface of the capsule and upper/lower surfaces of the retrodiscal pad (largest surface). Internal surface linings contain vili, or folds that allow the disc to translate by unfolding into a sheet when the jaw opens. The membrane is composed of 2 layers:

(1) Intima is adjacent to the joint space and is highly rich in arteriolar/capillary type blood vessels and lymph capillaries.

(2) Subintimal/Subsynovial Layer is outer layer composed of fibrous tissue and is poorly vascularized.

Front 126

Histology of the Synovial Membrane: Function

Back 126

Major function is to produce synovial fluid which provides nutrition for all non-vascularized portions of the joint, particularly the fibrous CT lining and the disc.

Normal joint fluid contains only a few free cells (58% monocytes and 38% macrophages- which remove free fragments that can cause wear and tear).

Some cells in the synovial membrane have phagocytic properties and can remove particulate matter- though process may take several months.

Front 127

Synovial Fluid in the TMJ

Back 127

Superior Joint Cavity = 1.2 ml

Inferior Joint Cavity = .9 ml

It is almost impossible to aspirate fluid from either cavity.

The synovial fluid function as a shock absorber is minimal in the TMJ (amount of fluid is small and joint is not subject to much compressive force.)

Front 128

Microscopic Innervation of the TMJ: 4 receptors

Back 128

(1) Corpuscles of Ruffini located in joint capsule (static mechanoreceptor)

(2) Golgi Tendon Organs located in ligaments (static mechanoreceptor)

(3) Free Nerve Endings are most abundant and acts as pain receptors.

(4) Pacinian Corpuscles are dynamic mechanoreceptors

ALL INVOLVED IN REFLEXES PROTECTING JOINT FROM DAMAGE

Front 129

Jaw Openers

Back 129

(1) Anterior Digastric

(2) Lateral Pterygoid

Front 130

Jaw Closers

Back 130

(1) Masseter

(2) Temporalis

(3) Medial Pterygoid

Front 131

Masseter

Back 131

Origin: zygomatic process of the maxilla and inferiorborder of zygomaticarch

Insertion: angle of the mandibleinferior, lateral side of ramus

Innervation: masseteric n.

Front 132

Temporalis

Back 132

Origin: temporal fossa andtemporal fascia (temporal lines of parietal bone)

Insertion: coronoid process ofthe mandible

Innervation: temporal nerve

Front 133

Medial Pterygoid

Back 133

Origin: pterygoid fossa and medial surface of lateralpterygoid plate

Insertion: medial aspects of the ramus and angle of the mandible

Innervation: medial pterygoid nerve

Front 134

Lateral Pterygoid

Back 134

Inferior Head Origin: lateral surface of lateral pterygoid plate

Superior Head Origin: infratemporal fossa of greater wing of sphenoid bone

Insertion: anterior neck of the mandible

Innervation: branch of masseteric or buccal n.

Function: pull condyle/diskalong the eminence

Front 135

Digastric

Back 135

Origin (posterior digastric): mastoid notch of temporalbone

Insertion (anterior digastric): lingual, inferior border ofthe mandible

Posterior Digastric Innervation: facial n.

Anterior Digastric Innervation: n to mylohyoid (V3)

Function: Lowers mandible, elevates hyoid

Front 136

Electromyography: Mechanism

Back 136

Muscle Action Potentials

Across Membrane: 90 mV (millivolts)

Extracellular: 90 uV (microvolts)

EMG signal is attenuated at the skin by about 1000

Front 137

Electromyography: Electrodes

Back 137

surface electrodes and needle electrodes

Front 138

Electromyography: Electronics

Back 138

1) amplifier

2) analog to digital converter

3) computer

4) display

Front 139

Electromyography: Caveats

Back 139

a) Electrical activity must be calibrated to relate directly to muscle force.

b) Jaw mm are redundant. SIx jaw closers are all active in jaw adduction. You cannot control the muscle independently. The forces on the jaw must satisfy newtons equations.

c) EMG only detects recruitment and frequency (NOT muscle length or contraction velocity)

Front 140

Determinants of Muscle Force

Back 140

1) recruitment

2) frequency

3) muscle length

4) velocity

Front 141

Electromyography: Strengths

Back 141

(A) know precisely when a muscle is active.

(B) know roughly how active.

(C) provides insight into MN activity

Front 142

Rest Position Hypothesis

Back 142

(1) Passive Elasticity

(2) Active Contraction

(a) stretch reflex

(b) TMJ receptors

(c) airway patency

Front 143

Rest Positon: Evidence

Back 143

Passive Elasticity:

• length tension curve
• negative EMG search

Active Contraction: FAVORED

• sleep in chair
  
• MN inhibition in sleep
  
• positive needle EMG
  
• positive surface EMG
  

Front 144

Rest Position: Evidence for Active Contraction (Surface EMG and sleep)

Back 144

Graph shows EMG activity during jaw opening. Rest Position is 2 mm open. Opening mouth to 7 mm involves decreasing muscle activity indicating it is being actively contracted at rest position.

Sleeping shows a similar result (when MN are turned off mouth opens).

Front 145

Mastication Hypothesis

Back 145

(1) Alternating Reflex (now disproved)

(2) Central Pattern Generator

Significance = Part of the theme "be skeptical and critical"

Front 146

Jaw Jerk Reflex

Back 146

POSTURAL AND MONOSYNAPTIC

• Masseteric n. afferent (muscle spindles) and efferent
• Muscle Spindles

Front 147

Jaw Opening Reflex

Back 147

PROTECTIVE and POLYSYNAPTIC

• Inferior alveolar n. afferent
• Digastric n. efferent

Front 148

Electronic Devices for TMD Diagnoses

Back 148

Hypotheses: both plausible but no convincing evidence

(1) resting EMG greater in TMD patients

(2) jaw position differs in TMD patients

Evidence to ask for:

(a) Sensitivity (ability to detect disease when present)

(b) Specificity (ability to detect normal when present)

Front 149

Swallowing (type of activity and control)

Back 149

Reflex Activity; Brain Stem

Front 150

Mastication (type of activity and control)

Back 150

Rhythmic Activity, Brain Stem

Front 151

Respiration (type of activity and control)

Back 151

Rhythmic Activty, Brain Stem

Front 152

Speech (type of activity and control)

Back 152

Voluntary Activity, Cortex

Front 153

Deglutition: Purpose

Back 153

58% awake but not eating

34% eating

8% sleeping

Front 154

Deglutition: Trigger

Back 154

Anterior Pilar = Glossopalatine Arch

Posterior Pilar = Pharyngopalatine Arch

Front 155

Deglutition: Afferent and Efferent Input

Back 155

AFFERENT (sensory nucleus):

CN VII, CN IX, CN X (Nucleus Tractus Solarius)

EFFERENT (motor nucleus):

CN V (trigeminal motor nucleus)

CN VII (facial nucleus)

CN IX & CN X (nucleus ambiguus)

CN XII (hypoglossal nucleus)

C1-C2 (spinal cord)

Front 156

Phases of Swallowing

Back 156

Oral: .5 sec, voluntary, facultative

Pharyngeal: .7 sec, involuntary, obligate

Esophageal: 3 sec (liquid) & 9 sec (solid), involuntary, obligate

Front 157

Obligate Muscles of Deglutition

Back 157

Pharyngeal fire at the same time.

• 5 muscles: mylohyoid, geniohyoid, posterior tongue,

palatopharyngeus, superior constrictor

Esophageal are delayed and sequential.

• 6 muscles: thyrohyoid, thyroarytenoid, middle constrictor, cricothyroid, inferior constrictor, diaphragm
  

Front 158

Respiration

Back 158

One of several activities in the orofacial region competing for attention. Respiratory control center located in the Medulla.

a) cyclic contraction/relaxation of the inspiratory mm only (in contrast to alternating of openers and closers in mastication)

b) skeletal mm (driven by MN's)

c) Typical rate: 15 breathes per minute

Front 159

Control of Respiration

Back 159

Respiratory Medulla receives input from mechanoreceptors, chemoreceptors, and the cerebral cortex. It sends nerve impulses to the spinal cord which stimulate respirtatory mm that alter the lungs and chest wall causing ventilation. Alveolar capillary barriers pass oxygen to blood via diffusion.

Feedback to mechanoreceptors (chest wall) and chemoreceptors (blood pH and partial pressures.

Front 160

Central Pattern Generator for Respiration

Back 160

CPG for respiration in the medulla.

1. Tonic Inspiratory Drive (to inspiratory muscles)

2. Excitation (signals from vagal stretch receptors)

3. Excitation of "cut-off switch" (signal from pneumotoxic center)

4. Inhibition (signal from peripheral and central chemoreceptors)

Front 161

Respiratory Cycle and Swallowing

Back 161

Swallowing usually occurs at the end of expiration.

It prolongs the respiratory cycle.

How frequently we swallow after expiration is based on controls. IT IS NOT RANDOM.

Front 162

Central Pattern Generation

Back 162

Neural Input starts and maintains the process.

The rhythm generator sets the overall length and duration of the cycle.

Front 163

Speech: Dental Problems

Back 163

A) caused by poor dentures... % speech errors after implant prosthesis

1. bilabial sounds (p/b).... 32%

2. labiodental sounds (f/v)... 23%

3. linguopalatal sounds (s/sh)... 33%

B) caused by other conditions

1. anterior open bite (f/v)

2. recessive mandible (p/b/m)

3. prognathism (f/v)

4. cleft palate (nasal speech)

Front 164

Speech: Physical Mechanisms

Back 164

1. respiration (lungs)

2. phonation (vocal cords)

3. resonance (sinuses)

4. articulation (lips and tongue)

CONTINUOUS ACTIVITY is a characteristic of muscles during speech

MEDIAL PTERYGOID INVOLVED IN SPEECH, MASSETER/TEMPORALIS MOSTLY UNINVOLVED.

Front 165

Speech: Development

Back 165

A. Innate ability to learn language rules.

B. Single words at about 1 year.

C. Rules of grammar at about 5 years.

D. Speech is uniquely human.

Front 166

Speech: Evolution

Back 166

A. All organs evolved for other functions (competition for use)

B. Control centers located in the cortex (not brain stem or spinal cord)

C. No development across species (origin of language is controversial)

Front 167

Posselts Sagittal Envelope

Back 167

(1) Posterior Opening Border

(2) Anterior Opening Border

(3) Superior Contact Border

(4) Functional Border

Front 168

Anterior/Posterior Borders (Sagittal)

Back 168

Posterior Border:

(1) Rotation

(2) Rotation and Translation

Anterior Border:

(3) Rotation and Translation

Front 169

Superior Contact Border (Sagittal)

Back 169

(0) Centric Occlusion

(1) Maximal Intercuspation

(2) Incisal Guidance

(3) Edge-to-Edge Position

(4) Beyond Edge-to-Edge

Front 170

What if CO and ICP are the same for an individual?

Back 170

There is no upward slide to start the movement.

Front 171

Superior Contact Border varies according to...

Back 171

Superior border movement is solely tooth dependent. Changes in the teeth will result in changes in the movement.

(1) amount of variation between CR and ICP

(2) steepness of the cuspal inclines of the posterior teeth

(3) amount of vertical and horizontal overlap of the anterior teeth

(4) lingual morphology of the maxillary teeth

(5) general interarch relationship of the teeth

Front 172

Influence of Head Posture

Back 172

Border movements are not effected by head or body posture.

Head posture does, however, influence the final closing position.

(A) Neutral Position: close to ICP

(B) Chin Up: close posterior to ICP

(C) Chin Down: close anterior to ICP

Front 173

Postural Rest Position (PP)

Back 173

NOT A BORDER POSITION

With-in the envelope 2-4 mm below ICP.

Front 174

Horizontal Plane Border

Back 174

(1) & (3) lateral borders are caused by contraction of the lat. pterygoid on the non-working side- rotating the non-working condyle around the frontal axis of the working condyle.

(2) & ( 4) protrusive movement as the working side lat. ptyerygoid contracts bringing the mandible both forward and back toward the midline.

Front 175

How does mandibular positioning affect the horizontal plane border?

Back 175

The amount of horizontal border movement decreases as the jaw is opened and you get further from the centric position.

Front 176

Frontal Plane Borders

Back 176

(1) & (3) are superior contact borders determined primarily by tooth contact. Concavity due to incisal edges to dipping to clear the maxillary arch.

(2) & (4) are lateral borders that produce convex pathways. The lateral maximum is reached and ligaments tighten pulling the mandible back toward the midline.

Front 177

Functional Movements: Sagittal

Back 177

Front 178

Functional Movements: Frontal

Back 178

Front 179

Incisal Guidance and Patient Movement

Back 179

(A) Normal

(B) No incisal guidance due to worn down teeth (note superior contact border shape)

(C) person can't open as wide (could be for number of reasons)

Less guidance also causes increased range of functional movements.

Front 180

Side Shift

Back 180

When the whole body of the mandible moves (shifts) toward the working side.

2 types:

(1) Progressive Side Shift is when the lateral movement of the mandible occurs throughout the entire movement

(2) Immediate Side Shift is when the shift occurs early in the movement and is completed before the condyles have finished rotating

Front 181

Retrusive Contacts

Back 181

Front 182

Protrusive Contacts

Back 182

Front 183

Mandibular Movements and Effect on Contact with Opposing Arch

Back 183

Maxilla:

Protrusive = shift anterior

Working Side = shift buccally

Non-Working = shift mesiolingually

Mandible:

Protrusive = shift posterior

Working Side = shift lingually

Non-Working = shift distobuccally

Front 184

Disclusion

Back 184

Loss of occlusal contact between opposing teeth during tooth-guided movements or positioning of the mandible.

NORMAL CONDITION- EXAMPLE IS POSTERIOR TEETH DISENGAGED DURING PROTRUSIVE MVMT FROM MIP DUE TO ANTERIOR GUIDANCE.

Front 185

Overbite

Back 185

Extension of the maxillary teeth over the mandibular teeth in a vertical direction when the opposing posterior teeth are in centric occlusion [vertical overlap]

Front 186

Overjet

Back 186

Projection of the maxillary anterior and/or posterior teeth beyond their protagonists in a horizontal direction when the mandible is in centric occlusion [horizontal overlap].

Front 187

Occlusal Stability

Back 187

Absence of a tendency for teeth to migrate with-in the dentition other than slow physiologic movements usually resulting from tooth wear.

Front 188

Malocclusion

Back 188

Any occlusion in which structural characteristics are beyond those established for theoretically ideal occlusion.

Doesn't necessarily imply such an occlusion is non-physiologic or that therapy is indicated. [physiologic occlusion = no therapy required]

Front 189

Therapeutic Occlusion

Back 189

An occlusion that has been modified by appropriate therapeutic modalities in order to change a non-physiologic occlusion to one that, at the least, falls with-in the parameters of a physiologic occlusion- if not theoretically ideal.

Such an occlusion may contain structural modifications not necessarily found in nature, in order to optimize the health and adaptive potential of the masticatory system.

Front 190

Crossbite

Back 190

Maxillary BUCCAL cusps contact the CF in the opposing mandibular teeth.

Due to discrepancies in skeletal arch size or eruption pattern.

Front 191

Interarch Relationship of Maxillary and Mandibular Teeth

Back 191

Mandibular teeth are situated slightly lingual and mesial to their maxillary counterparts.

Front 192

Who Invented the Face Bow?

Back 192

George Snow, 1907

Front 193

Who Invented the first simple articulator?

Back 193

Gariot, 1805

Front 194

Functions of the FaceBow?

Back 194

• relates maxillary cast to the TMJ
  
• permits accurate fabrication of restorations based on mand mvmts
• permits general restorative diagnosis and Tx planning
• permits occlusal analysis
• only can function correctly with accurate mandibular cast mounting

Front 195

Facebow: Reference Planes

Back 195

Axis-Orbitale Plane: true hinge axis

Frankfort Plane: arbitrary hinge axis

Front 196

Gysi's Point

Back 196

10 mm anterior to the posterior margin of the tragus on a line from the center of the tragus to the outer canthus of the eye

Front 197

Beyron's Point

Back 197

13 mm anterior to the posterior margin of the tragus on a line from the center of the tragus to the outer canthus of the eye

WHERE TRUE HINGE AXIS IS LOCATED.

Front 198

Fascia Facebow

Back 198

- Used orbitale as reference point

- Ruler parallel to inter pupillary line

- ONLY 2 POINTS OF REFERENCE [basically a bite registration]

Front 199

Ear Facebow

Back 199

- anterior reference point is ORBITALE

- posterior reference point is PORION

ARBITRARY AXIS IS THE CIRCLE 10 mm BEHIND THE EAR PIECE

TYPICAL TO USE SPRING BOW INSERT FOR POSTERIOR REFERENCE POINTS

MOUNT TO MAXIMAL INTERCUSPATION

[ONLY MOUNT TO CENTRIC RELATION FOR COMPLETE DENTURES]

Front 200

Accuracy of an Arbitrary Axis

Back 200

"the estimated axis location for most facebows will place the position of the arbitrary axis with +/- 6 mm of the true axis 80% of the time"

Front 201

Open Incisial Pin 3 mm...

Back 201

Anterior opening 2 mm

Posterior opening 1 mm

Front 202

Weinberg Principle for Selecting Axis

Back 202

• Selecting terminal hinge axis 5 mm too far posterior using a 3 mm thick interocclusal record would produce an error of .2 mm at the 2nd molar location at closure into occlusion
• a 5 mm error is practical and dependable for orienting the maxillary cast
• Limiting interocclusal opening to 6 mm will produce negligible error

Front 203

REARWARD CAST MOUNTING

Back 203

CONDYLE BEHIND HINGE AXIS [INFERIOR CONDYLE]

ANTERIOR TEETH PREMATURITY

POSTERIOR OPEN CONTACT

Front 204

FOREWARD CAST MOUNTING

Back 204

CONDYLE IN FRONT OF HINGE AXIS [SUPERIOR CONDYLE]

POSTERIOR TEETH PREMATURITY

ANTERIOR OPEN CONTACT

Front 205

HIGH CAST MOUNTING

Back 205

CONDYLE IS ABOVE HINGE AXIS [RETRUDED CONDYLE]

ANTERIOR TEETH PREMATURITY

POSTERIOR OPEN CONTACT

Front 206

LOW CAST MOUNTING

Back 206

CONDYLE IS BELOW HINGE AXIS [PROTRUDED CONDYLE]

POSTERIOR TEETH PREMATURITY

ANTERIOR OPEN CONTACT

Front 207

When is True Hinge Axis (terminal hinge axis) required for patients?

Back 207

- training programs

- very large rehabilitative restorations that require alteration of VDO

- high cusp angle interdigitation

Front 208

When is arbitrary hinge axis required?

Back 208

- large rehab restorations

- to mimimize occlusal error with any restoration

- esthetic restorations when visualization and orientation required to fabricate restoration

Front 209

Requirement of an Articulator

Back 209

- holds cast in correct horizontal and vertical position

- provides a positive anterior vertical stop [incisal pin]

- hinge, lateral, and protrusive movements

- accept facebow transfer

- components move freely/machined accurately

- adjustable horizontal/lateral guides

- CONDYLAR GUIDES [MECHANICAL FOSSA] AS UPPER FRAME

- CONDYLAR ELEMENTS AS LOWER FRAME

- ALLOW MECHANISM TO ACCEPT 3rd REFERENCE POINT FROM FACEBOW

Front 210

Limitations of the Articulator

Back 210

- mandibular movements are complex 3D movements with the added dimension of TIMING [can't transfer dimension of timing to an articulator]

- SIMULATE mandibular movements [CAN NOT duplicate the movements]

- Instrument only as good as the operators ability to transfer the information accurately and use the features

Front 211

WEINBERG CLASSIFICATION FOR ARTICULATORS

Back 211

1. ARBITRARY

2. POSITIONAL

3. SEMI-ADJUSTABLE

• non-arcon
  
• arcon

4. FULLY ADJUSTABLE

Front 212

Arbitrary Articular

Back 212

- not related to human anatomy

- just a mounting of the cast

- open and close but NO HINGE MOVEMENT (up & down)

- Monson articulator

- Hagman Balancer

Front 213

Positional Articulator

Back 213

- Only one position is accurate

- Stansberry Tripod

Front 214

Arcon Semi-Adjustable Articulator

Back 214

*represents the anatomy of the patient

- MECHANICAL FOSSA ON UPPER... CONDYLAR SPHERES ON LOWER

- angulation of mechanical fossa is FIXED relative to the occlusal plane

- set intercondylar distance of 110 mm

- adjustable protrusive angle [30 degrees]

- centric lock

- curved condylar path to represent natural movement

- HANUA MODULAR ARTICULATOR

Front 215

Non-Arcon Semi-Adjustable Articulator

Back 215

*DO NOT REPRESENT ANATOMY OF PATIENT

- MECHANICAL FOSSA ON LOWER/CONDYLAR SPHERE ON UPPER

- angulation of the mechanical fossa relative to occlusal plane is NOT FIXED

• [angle changes when you open the articulator]
  

Front 216

Limitations of the Semi-Adjsutable Articulator

Back 216

- no laterotrusive movement of working side condyle

- possible horizontal ridge and groove pathway occlusal interferences

[effects angles between medio- and latero- trusive pathways]

- designed to have a PROGRESSIVE SIDE SHIFT [can't set immediate shift]

- no lateral movement of rotating condyle [possible buccal cusp interference on working side & vertical cusp height determinant]

Front 217

Fully Adjustable Articulator

Back 217

- 3D movements can be reproduced with simulataneous pantographic tracings containing 3 planes of space

- difficult to use/not really necessary

- can't use with facebow and must trace movements

- DENAR MK V articulator

Front 218

Limitations of HINGE ARTICULATORS

Back 218

1) Distance from condylar axis effects effects the arc of closure contacts [very short distance on hinge articulator]

2) Intercondylar Distance causing disparity in the laterotrusive and mediotrusive pathways.

3) No condylar excursive movement capabilities.

Front 219

Factors of Occlusal Morphology

Back 219

1. Neuromuscular [mastication, bruxism, bite force]

2. Diet

3. Age

4. Quality of Occlusal Forces

5. Relationship of Skeletal Components

6. Position of Condylar Axis

7. Vertical/Horizontal Components

Front 220

Mastication

Back 220

1. OPENING PHASE

- working side rotates/non-working translates

- mandible moves forward on working side

2. CRUSHING PHASE

- condyle of working side retrudes posterior and laterally

3. GRINDING PHASE

- final closure to MIP

- bodily movement of mandible on working side [bennett movement]

CHEWING HARD FOOD = WIDE CLOSURE/CANINE GLIDING CONTACTS

Front 221

Bruxism

Back 221

- bruxism and nothing else = NO BONE LOSS

- EMG during nocturnal: bilateral rhythmic bursts followed by 20s of sustained contraction

- no cure

- teeth flatten and shorten

- mouth guard can protect/help prevent additional damage

Front 222

BITE FORCE

Back 222

AVG: 150-250 LBS

MAX. PARAFUNCTION: 1000 LBS

VETERAN EDENTULOUS: 5-8 LBS

MAX EDENTULOUS: 50 LBS

Front 223

2. DIET

Back 223

When you must grind food more you can wear down your supporting cusps....

- can result in a REVERSE CURVE OF WILSON

Front 224

4. QUALITY OF OCCLUDING SURFACES

Back 224

IATROGENIC: problem caused by treatment

- rough surfaces can cause problems

- zirconium hard to polish/may cause wear

Front 225

6. Position of Condylar Axis

Back 225

Length of mandible varies, effecting the posterior cusps.

Short Mandible [SMALL ANGLE] = SHARPER CUSPS

Tall Mandible [LARGER ANGLE] = SHALLOW CUSPS

Front 226

VERTICAL DETERMINANTS

Back 226

FACTORS THAT INFLUENCE CUSP HIEGHT AND HOW FAR THEY EXTEND INTO DEPTHS OF FOSSA

1. Condylar Guidance [Angle of Eminence]

2. Anterior Guidance

3. Plane of Occlusion

4. Curve of Spee

5. Lateral Translation Movement

(1) PCF, (2) ACF, AND (3-5) NEARNESS OF CUSP TO CF's

Front 227

HORIZONTAL DETERMINANTS

Back 227

FACTORS INFLUENCING THE DIRECTION OF RIDGES/GROOVES THROUGH THE MEDIO- AND LATEROTRUSIVE PATHWAYS GENERATED

1. Distance between tooth & ROTATING CONDYLE

2. Distance between tooth & MIDSAGGITAL PLANE

3. Lateral Translation Movement

4. Intercondylar Distance

Front 228

Taller Cusp Heights....

Back 228

Front 229

Smaller Angle between medio- and latero- trusive pathways...

Back 229

Front 230

"Health" [of occlusion]

Back 230

structures of occlusal anatomy are in harmony with the structures controlling the movement patterns of the mandible.

In any given moment, anatomical relationships [TMJ and anterior teeth] dictate a precise and repeatable pathway.

To maintain harmony of occlusal condition = posterior teeth pass close to but don't contact opposing teeth during a mandibular movement

Front 231

Two Structures Controlling Mandibular Movements

Back 231

1. Posterior Controlling Factor: TMJ

2. Anterior Controlling Factor: Anterior Teeth

- note posterior teeth are in between the two factors, and can be influenced by both...

ACF's and PCF's ARE INDEPENDENT OF ONE ANOTHER, BUT STILL FUNCTION TOGETHER TO CONTROL MANDIBULAR MVMT

Front 232

POSTERIOR CONTROLLING FACTORS [PCF's]

Back 232

- angle to which condyle moves away from the horizontal reference plane [angle of eminence or condylar guidance angle]

- condylar guidance forms a larger angle of mandibular movement during during lateral mvmt than during protrusive movement [medial wall of fossa is steeper compared to fossa anterior to condyle]

- FIXED FACTOR

Front 233

ANTERIOR CONTROLLING FACTORS [ACF's]

Back 233

- Incisal Guidance

VARIABLE FACTOR

• alterations [restoration/ortho/extraction]
  
• pathologic [wear, caries, habits]

* variation of ACF's an important part of treating occlusal disturbances

Front 234

Nearer the tooth is to the TMJ...

Back 234

THE MORE THE JOINT ANATOMY WILL EFFECT IS ECCENTRIC MOVEMENT AND THE LESS THE ANATOMY OF THE ANTERIOR TEETH WILL INFLUENCE ITS MOVEMENT.

[LIKEWISE FOR NEARNESS TO ANTERIOR TEETH]

Front 235

Ratio/Relationship Between Vertical and Horizontal Determinants

Back 235

IMPORTANT TO MANDIBULAR MOVEMENTS BECAUSE:

VERTICAL COMPONENT = function of superoinferior movements

HORIZONTAL COMPONENT = function of anteroposterior movements

ANGLE OF DEVIATION FROM HORIZONTAL REFERENCE PLANE IS WHAT CLINICIANS STUDY IN MANDIBULAR MOVEMENT

Front 236

ORIENTATION OF THE CURVE OF SPEE

Back 236

WHERE IS RADIUS FALLS RELATIVE TO LINE PERPENDICULAR TO HORIZONTAL REFERENCE PLANE CAN ALSO HAVE AN EFFECT.

All cusps posterior to this line will need shorter cusps than those anterior to it.

- If radius is further posterior, more teeth will be located distal to the line and have shorter cusps.

- If radius is further anterior, more teeth will be located in front of the line and have longer cusps.

Front 237

DEGREE OF INWARD MOVEMENT OF THE NON-WORKING CONDYLE:

Back 237

INFLUENCED BY:

1) Morphology of Medial Wall of Mandibular Fossa

2) Inner Horizontal Portion of TMJ Ligament

No Movement when TM LIGAMENT [WORKING SIDE] IS TIGHT and MEDIAL WALL IS CLOSE TO NON-WORKING CONDYLE

Lateral movement when ligament loose and non-working condyle moves inward to lateral wall

Front 238

3 ATTRIBUTES OF THE LATERAL TRANSLATION MOVEMENT

Back 238

1. AMOUNT

2. TIMING [greatest effect on posterior teeth]

3. DIRECTION

Front 239

Timing of lateral translation...

Back 239

If the Side Shift is PROGRESSIVE, amount and direction have little effect on occlusal morphology.

But if it's immediate, they have a massive effect.

Front 240

Amount of lateral translation...

Back 240

Looser ligament & more medial wall = greater amount of lateral translation movement

Front 241

Direction of lateral translation movement...

Back 241

- DEPENDS ON DIRECTION TAKEN BY THE ROTATING (WORKING) CONDYLE DURING THE BODY MOVEMENT

- 60 DEGREE CONE ALLOWING COMBINED LATERAL MOVEMENT IN ANTERIOR/POSTERIOR/INFERIOR/SUPERIOR DIRECTIONS

LATEROSUPERIOR MOVEMENT --> SHORTER CUSPS

LATEROINFERIOR MOVEMENT --> LONGER CUSPS

Front 242

Distance from tooth to Rotating condyle-

Maxillary vs Mandibular pathways...

Back 242

Maxillary Pathway = generated more distally

Mandibular Pathway = generated more mesially

Front 243

Distance from tooth to Mid-sagiital plane-

relative effect

Back 243

PROXIMITY TO MID-SAGITAL PLANE OUTWEIGHS EFFECT OF DISTANCE FROM THE ROTATING CONDYLE.

Generally as one increases the other decreases, but since distance from condyle changes faster PREMOLARS GENERALLY HAVE WIDER ANGLES BETWEEN PATHWAYS THAN THE MOLARS

Front 244

TMD STATS

Back 244

- 75% of population

- 5-10% diagnosable disorder

- most common tx among dentists is splints

- women more frequently affected

- start to build in teenage years until late 30's then decrease/fade out [not a progressive disease]

Front 245

TMD Symptoms

Back 245

Pain in the facial and preauricular area and may include headache

Pain aggravated by jaw function

Frequently accompanied by:

- Limitation of jaw movement

- Joint sounds

- Pain from palpation of muscles and joints

Front 246

Appropriate Diagnostic Standards

Back 246

- Clinical Evaluation [operationalized, reliable, algorithm-driven]

- Biomedical Diagnosis [muscle, disk, or arthritic disorder]

- Assessment of the Person [function, psychological, co-morbid symptoms, impact of pain on functioning]

Front 247

Dual Axis Classification of TMD

Back 247

AXIS I = biomedical model, physical disease

AXIS II = biopsychosocial model, bio-behavioral assessment of the person

Front 248

Primary TMD Types

Back 248

1. Pain Disorders

2. Mechanical Joint Disorders

3. Degenerative Joint Disorders

Front 249

Pain Disorders

Back 249

myalgia: muscle disorder

arthralgia: pain in joint

Front 250

Mechanical Joint Problems

Back 250

Disk displacement with reduction

Disk displacement with locking

Disk displacement without reduction

Front 251

Degenerative Joint Disorders

Back 251

Osteoarthrosis: observed on radiograph

Osteoarthritis: symptomatic

- breakdown of condyle and cortical plate

- disc breaks down and shreds

- for many, still functional is not overdoing the system

- opposite mechanism of rheumatoid arthritis

Front 252

Signs and Symptoms of TMD

Back 252

Regional pain

Limitation in mobility

Decreased function

Pain on palpation of muscles and joints

TMJ noises

Front 253

Why is there no evidence for causation between occlusion and TMD?

Back 253

1. Ideal occlusion exist in 5% of population

2. distribution of age & gender of TMD vs Malocclusion

3. Clinical Observational Studies overall have not been replicable, show CNS capacity for adaptation, and individual variability in biology

4. Static occlusion very different from dynamic occlusion

5. Experimental studies showing occlusion interference doesn't trigger new TMD cases & hypervigilance is more important

6. Unpredictable and non-specific treatment response to oral appliances and occlusal adjustment (unknown pathology)

Front 254

STATIC vs DYNAMIC OCCLUSION

Back 254

STATICS: account for 5% variance in TMD

- anterior open bite

- CR to MIP > 2 mm [and asymmetric]

- overjet > 4 mm

- 5 or more missing teeth

DYNAMICS:

- degree of orthopedic instability

- amount of loading [bruxism, unilateral chewing]

- frequnecy of loading

- accessory loading

Front 255

Model for Role of Occlusion Affection Masticatory System

Back 255

[Normal Function + an 'event'] > [Physiological Tolerance] = TMD SYMPTOMS

Normal Function: chew, swallow, speak, emotional expression, breathe

Events:

a) Local: occlusal changes, sudden strain, overuse, deep pain

b) Systemic: emotional, hormonal, general disease

Physiological Tolerance:

a) Local: departures from stable occlusion [condylar instability, non-longitudinal tooth forces, inappropriate disclusion, iatrogenic/developmental...]

b) Systemic: stress, anxiety, depression, personality

Front 256

Occlusal Dysthesia

Back 256

Persistant, Uncomfortable Bite

Perception or focus leading to perceived symptoms.

Front 257

Bonwill

Back 257

Front 258

Spee

Back 258

1. CONTACT SURFACE OF MANDIBLULAR TEETH GLIDE AGAISNT MAXILLARY TEETH

2. AREA OF CONTACT LIE ON SAME CYLINDRICAL SURFACE

3. HORIZONTAL AXIS OF CURVATURE PASS THROUGH MIDDLE OF MESIAL SURFACE OF ORBIT

Front 259

Monson

Back 259

Front 260

Balkwill

Back 260

Discovered Bennett Movement

Front 261

Bennett

Back 261

Wrote Paper on Bennet Movement

Front 262

Di'Amico

Back 262

Canine Protection

Front 263

Christenson's Phenomenon

Back 263

Front 264

Gysi

Back 264

Front 265

Walker

Back 265

Front 266

McCollum

Back 266

Kinematic Face Bow

Front 267

Stuart and Stallard

Back 267

Front 268

Schuyler

Back 268

- Concluded that balanced contacts of the posterior teeth in either lateral or protrusive eccentric functional movements may be desirable for complete dentures but they are NOT essential for the stability of natural teeth.

- The value in distributing functional stress is negative

- Shifted away from balanced occlusion in the natural dentition

FUNCTIONALISM: sucharrangements of the teeth as will provide the highest efficiency during all the excursions of the mandible which arenecessary to the function of mastication.

Front 269

Beyron

Back 269

Front 270

An evidence-baseddiagnostic system for a disease/disorder such as TMD should include which ofthe following elements:

Back 270

Clearly defined procedures

Examiner Reliability

Biological Plausibility

Front 271

The primary characteristicsof TMD include:

Back 271

Preauricular Pain

Limitation of Mobility

Palpable Tenderness of Muscles

Front 272

A common type of occlusalproblem is the measured discrepancies between the retruded jaw position(centric occlusion) and the maximal position of tooth intercuspation; thesediscrepancies are:

Back 272

equally common in individuals with TMD as thosewithout TMD

Front 273

TRUE or FALSE:

Limitation ofmovement, one of the primary characteristics of TMD, occurs very often due to mechanicalproblems within the TMJ

Back 273

FALSE.

Limitation of movementusually has something to do with the brain telling your muscles that theycannot go past a certain point.

It is MYOFASCIAL that primarily accounts forthe majority of TMJ. (can be clenching, etc.)

Front 274

It isoften claimed in the scientific research that TMD is a ___________ disorder,most often without serious morbidity. What evidence supports this claim?

Back 274

SELF-LIMITING.

Populationepidemiology demonstrates that the prevalence of TMD decreases markedly afterthe age of 40

Front 275

Accordingto material presented during the lecture, what are the appropriate diagnostic standards for TMD:

Back 275

Clinical Evaluation

Biomedical Diagnosis

Assessment of the Person

Front 276

The primary forms of TMD in terms of prevalence are:

Back 276

Myofascial Disorders

Arthritis

Intracapsular Disorders

Front 277

Anindividual subjected to a severe head and neck trauma that paralyzed his softpalate would most likely demonstrate which of speech issue/s:

Back 277

Nasal Speech

Front 278

Defective dentures may cause what speech issues?

Back 278

Defective "f" sounds

Defective "s" sounds

Linguopalatal Sounds [s/sh]

Front 279

Your facebow (Spring bow) is aligned to yourModular Hanau articulator axis via:

Back 279

An anterior horizontal mounting offset of approximately 10 mm

Front 280

T or F.

Bonwills articulator not only produced balanced occlusion but allowed adjustment of the condylar elements.

Back 280

F.

No condylar adjustments.

Front 281

Balanced Occlusion Includes the following:

Back 281

- Working Side Tooth Contacts

- Working Side Cross-Tooth Contacts

- Balancing Side Contacts

- Protrusive posterior/anterior contacts

Front 282

Bonwill's Triangle...

Back 282

10 cm equilateral triangle extending from condyles to MI angle of MANDIBULAR central incisors.

Front 283

In most individuals, when the dentition occludesin centric occlusion, the mandibular arch is:

Back 283

POSTERIOR to the MIP

Front 284

In most individuals, when the dentition occludesin maximal intercuspation, the mandibular arch is:

Back 284

ANTERIOR to the CR [centric position]

Front 285

Which of the following are remnants of Meckel’scartilage?

1. Condyle

2. Body of mandible

3. Malleus

4. Stylomandibular ligament

5. Sphenomandibular ligament

6. Articular disk

7. Anterior mallear ligament

Back 285

Malleus, Sphenomandibular Ligament, and Anterior Mallear Ligament

[3, 5, 7]

Front 286

The role of the rhythm generator in the central patterngenerator is:

Back 286

Set the overall lengthand duration of the cycle

Front 287

Therole of the cortex in the central pattern generator formastication is:

Back 287

Start and Maintain the Process

Front 288

Which of the following are considered trigeminal reflexes:

1. Jaw opening reflex

2. Breathing

3. Blink reflex

4. Jaw closing reflex

5. Gagging

6. Chewing

7. Speaking

Back 288

Jaw Opening Reflex, Blink Reflex, Jaw Closing Reflex, Gagging

[1,3,4,5]

Front 289

The mandibular border movements along thesuperior border of Posseltt’s envelope of motion is limited by:

Back 289

Tooth Contact

Front 290

The reference plane for the hinge axisface bow is:

Back 290

AXIS-ORBITAL

Front 291

The anterior reference point for the face bowused with your modular articulator is:

Back 291

ORBITALE

Front 292

The occlusal scheme proposed by Bonvillemploying 10 cm equilateral triangle articulator concept was:

Back 292

BILATERAL BALANCED OCCLUSION

Front 293

Incisal guidance is best characterized by:

Back 293

A. Occurs during protrusive movement

B. Is influenced by horizontal and vertical overlapof anterior teeth

C. Is influenced by anatomy of maxillary andmandibular teeth

Front 294

Common Pattern of Attrition

Back 294

More rapid wear of maxillary lingual and mandibular buccal cusps [supporting cusps]

Front 295

Moving from canines to 3rd molars...

[cusp height and MD distance between buccal cusps]

Back 295

Mesiodistal Distance between buccal cusps becomes progressively shorter.

Cusp Height Gradually decreases [more vertical path during closure]

Front 296

Cross Tooth Balance

Back 296

Movement to lateral excursion with simultaneous buccal-to-buccal and lingual-to-lingual cuspcontact on the working side

[BALANCED OCCLUSION]

Front 297

Cross Arch Balance

Back 297

Movement to lateral excursion with Maxillary Lingual-to-Mandibular Buccal cusp contact on thenon-working side

[BALANCED OCCLUSION]

Front 298

Protrusive Balance

Back 298

Protrusivemovement with simultaneous contact of maxillary and mandibular incisors, as well as maxillary and mandibularposterior teeth

[BALANCED OCCLUSION]

Front 299

The Reference Plane for the Hanau Articulator is:

Back 299

Frankfort Horizontal Plane

Front 300

Iffollowing completion of orthodontic treatment, a tooth is not placed in aneutral space position and there are no obstructions to subsequent movement,what is a potential physiologic sequelae?

Back 300

The tooth will likely move to aposition where the muscular forces on the tooth are inequilibrium.

Front 301

Thepicture below illustrates part of the technique used to mount the Hanau Spring Bow. What is the purpose of theoffset depicted in the picture?

Back 301

Relate the facebow to arbitrary hinge axis

[not relate the facebow to the Frankfort-Orbitale plane for some reason- though that was the arbitrary hinge axis]