FUNDAMENTALS OF OCCLUSION AND MANDIBULAR MOVEMENTS

What part of the TMJ is responsible for translation?

What is it called?

Superior - Arthroidal

What part of the TMJ is responsible for rotation?

What is it called?

Inferior - Gingylmoid

What are the 6 possible movements of TMJ

Laterotrusion

Mediotrusion

Surtrusion

Detrusion

Retrusion

Protrusion

Significance of Mandibular Movements

Recording __ relations

_____, ______ and _____ of articulator

Creating a tooth form for ________

Understanding basic ________

Dignosing and treating _____ disturbances

Preserving _______ health

Jaw

Designing, adjustment, selection

Restorations

Occlusion

TMJ

Perio

Excursive Movement:

Occurs when mandible moves ________ from ______

Combination of ______ and ______

Away from MI

Rotation and translation

What are the three types of excursive movements

Opening and closing

Protrusion and retrotrution

Lateral

What three positions are border movements recorded in

Sagittal

Frontal

Horizontal

Border Movement in the Sagitaal Plane (4)

Centric

Max protrusion

Max opening

CLosing and return to centric

Border movement in horizontal plane (4)

Centric

Right and left extreme movements

Max protrusion

Close and return to centric

Border movement in frontal plane (4)

Centric

Right and left extremes

Max opening

Close and return to centric

All functional movements of the mandible occur within what

Envelope of motion

What are the functional movements of the mandible? (4)

What shape are they?

What planes are they viewed in?

Chewing, swallowing, speaking, yawning

Tear drop

All

Bennet Movement:

What side rotates?

What side orbits / translates?

Working - Side youre chewing on

Non working - Side youre not chewing on

Bennet Movement is defined as condylar movement on the _____ side in the ____ plane

Working

Horizontal

What is the bennett angle formed between?

When?

What value range?

Sagittal plane and condylar path

During lateral mand movements

0-35

Bennett Angle / Hanau formula

Range value? Mean?

L = H/8 = !2 (H = horizontal condylar guidance, L = lateral condylar guidance)

2-44, 16

What mandibular movements is masseter responsible for

CLosing and retrusion

What mandibular movements is temporalis responsible for

Elevation and retrution

What mandibular movements is medial pterygoid responsible for

Closing and lateral

What mandibular movements is lateral pterygoid responsible for

Opening, protrusion, lateral

What mandibular movements are suprahyoid muscles responsible for

Depress

Parafunctional activities associated with:

Chewing

Swallowing

Speech

Bruxism

Clenching

Pipe smoking, pencil biting, safety pin opening

Sustained movements of mandible that occur orther than normal

What can they cause?

Parafunctional movements

Restricted mandibular movements

More common parafunctional habits

Bruxism and clenching

What are the two divisions of Centric Occlusion

Centric Relation

Maximum Intercuspation

Centric occlusion is a _____ to _____ relation

Centric relation is a _____ to ______ relation

Tooth to tooth

Bone to bone

Occlusion of teeth as the mandible closes in centric relation

Centric Occlusion

The reference point from which all other relations are eccentric

Centric Occlusion

The relation between maxilla and mandible when condyles are in rear upper mid most in the glenoid fossa

Centric Relation

Most closed complete interdigitation of mandibular and maxillary teeth

What is it irrespective of?

Maximum intercuspation

Condylar centricity

Does maximum intercuspation coincide with centric occlusion?

Why?

Not always

Depends on position of condyle

If maximum intercuspation occurs with condyles out of centricity, it is refferred to as what

What is it considered?

Habitual or physiological occlusion / closure

Eccentric position

What is ideal occlusion?

What % of the population has this?

Maximum intercuspation coinciding with centric relation

Very low %

Why is centric relation the universally accepted jaw position? (2)

Physiologically and biomechanically correct

Only jaw position that permits interference free occlusion

Occlusion that refers of contact of teeth that occurs during movement of mandible

Eccentric Occlusion

Contact between oppostin teeth when mandible is moved R or L, contacts occur on sides toward which mandible moves

Lateral / Working / Functional Occlusion

Positon of mandible is anterior to centric relation is what occlusion

Protruded

What teeth ideally contact in protruded occlusion

Disocclude?

6 anteriors along the lingual inclines of maxillary anteriors

Posteriors

What is balancing (nonfunctional) side occlusion

Tooth contacts that occur away from the side the mandible moves

What is unilateral balanced occlusion other name?

What teeth contact? Not?

Group Function

Simultaneous contact of max and mand teeth on working side

No contact on non working (balancing) side

What is bilatreal balanced occlusion?

Both working and balancing (non working) side have simultanous contact of maxillary and mand teeth in anterior and posteriors through all eccentric movements

Is bilateral balanced occlusion found in natural dentition?

What is it needed for?

No

Denture stability

What type of occlusion is widely accpeted, easy fabricated and has greater tolerance by patients

Canine Guided (protected) occlusion

In unilateral balanced occlusion, what teeth are in contact in lateral excursive movements

All teeth on working side

Why is mutually protected occlusion called what it is?

Anterior teeth protect posteriors during mandibular excursions, posteriors protect anteriors in intercuspal position

Occlusion classes are based on what tooth

First max molar

What is Class I occlusion called?

What occludes?

Neutro occlusion

MB cusp of first molar occludes with MB groove of lower first permanent molar

What is Class II occlusion called?

WHy?

Disto occlusion

Mandibular first molar is posterior to class I

What is Class III occlusion called?

Why

Mesio Occlusion

Mand first molar is anterior to class I

What are the three main categories of interocclusal registration

Centric intercuspal records (CO or MI)

Centric Interocclusal record (CR)

Eccentric interocclusal records (lateral and protrusive)

What is the goal of treatment in fixed if the patient has stable intercuspal position

Maintaining pretreatment intercuspation and occlusal vertical dimension

What is the goal of treatment in fixed if patient has unstable intercuspal position with signs and symptoms from occlusion?

Direct towards centric reltaion

Centric Relation is independent of ________, in which the condyles articulate in the _______-______ position

In this position, the mandible is restricted to what type of movement?

Tooth contact, anterior-superior

Rotary

Occlusion of opposing teeth when mandible is in centric relation

Does it coincide with max intercuspal position

Centric Occlusion

May or may not

Sometimes referred to as the best fit of teeth regardless of condylar position

Maximal intercuspal position