4/17: Determinants of Occlusal Morphology II

Question 1

What do horizontal forces influence?

Answer 1

The direction of the ridges an grooves on the occlusal surfaces, and also the placement of the cusps

Question 2

What does it mean that the mandible moves medially?

Answer 2

Right mediotrusion means that the right condyle moves medially (same as left lateral movement)

Question 3

What is the non working pathway called?

Answer 3

Mediotrusive pathways

Question 4

What does it mean that the mandible moves laterally?

Answer 4

Right laterotrusion means that the right condyle moves laterally (same as right lateral movement)
- right lateral, mediotrusion left
A: non-working pathway or mediotrusive pathway

Question 5

What are the working pathways also called?

Answer 5

Laterotrusive pathways

Question 6

What are horizontal factors?

Answer 6

• distance from the rotating condyle
• distance form the midsagital plane
• amount of mandibular lateral translation
• intercondylar width

Question 7

Horizontal factors are the effect of distance of the tooth from the ________ and ___________

Answer 7

Rotating condyle; midsagittal plane

Question 8

Horzontal movements are the effect of what three things?

Answer 8

1. Effect of distance of the tooth from the
   - rotating condyle
   - midsagittal plane
2. Effect of mandibular lateral translation movement
3. Effect of intercondylar distance

Question 9

The greater the distance of the tooth from the rotating condyle, the _______ the angle formed by the working and non working pathways

Answer 9

Wider
- same in the mandible and maxilla

Question 10

Most of the times teeth that are closer to the midsagittal plane will be at ___________ distance from the rotating condyle

Answer 10

Greater

Question 11

What do teeth that are positioned more anteriorly in the jaw (premolars) tend to have?

Answer 11

Greater angles between mediotrusive and laterotrusive pathways compared to teeth that are positioned more posteriorly (i.e., molars)

Question 12

What does the angle formed by the working and non working pathways increase?

Answer 12

The amount of lateral translation increases
- the direction of the lateral translation also influences the angle
- same in the mandible and maxilla

Question 13

The angle formed by the working and non working pathways _________ as the intercondylar distance ___________

Answer 13

Decreases; increases

Question 14

Describe composite movements in a cusp fossa relationship

Answer 14

Question 15

What is another term for working interfering contact?

Answer 15

Laterotrusive contacts

Question 16

What is another term for non working interfering contact?

Answer 16

Mediotrusive contacts

Question 17

What are three components of the masticatory system?

Answer 17

Mastication
Swallowing
Speech

Question 18

What is mastication?

Answer 18

Initial stage of digestion

Question 19

What is control of the central pattern generator?

Answer 19

Rhythmic separation and closure of the teeth
- autonomic/involuntary- can be controlled voluntarily

Question 20

What is the chewing stroke?

Answer 20

Single cycle of opening and closing

Question 21

What shape is the chewing stroke?

Answer 21

Tear shaped pattern (frontal)

Question 22

What are the phases of the chewing stroke?

Answer 22

Opening phase
Closing phase
- crushing phase
- grinding phase

Question 23

Where does the chewing stroke begin and end?

Answer 23

At MIP

Question 24

What creates more vertical chewing stroke?

Answer 24

Taller cusps
Depper fossae

Question 25

Most people have a preferred ___________

Answer 25

Chewing stroke

Question 26

What occurs during mastication?

Answer 26

Tooth contacts

Question 27

What is increased as food is broken down?

Answer 27

Increased frequency of contacts - gliding contact (cuspal inclines) - single contacts (MIP contacts)

Question 28

What is the average length of time of contact?

Answer 28

194 MSEC

Question 29

How do forces vary in maximal biting forces?

Answer 29

Male > female Skeletal relationships and occlusion Race (eskimos) Anterior or posterior tooth mastication or swallowing

Question 30

What is the average max biting force?

Answer 30

80 to 150lbs (greatest was 975 lbs)

Question 31

When is forces least?

Answer 31

For chewing (36% of max biting)

Question 32

What is the biting force of dentures?

Answer 32

1/4 that of natural teeth

Question 33

What is the definition of swallowing?

Answer 33

Series of coordinated muscular contractions that move a bolus of food from th eoral cavity through the esophagus to the stomach

Question 34

What kind of muscle activity is swallowing?

Answer 34

Voluntary/involuntary reflex - somtaic/visceral swallow

Question 35

During swallowing, what is the mandible stabilized by?

Answer 35

Tooth contacts (MIP)

Question 36

How long is tooth contact during swallowing?

Answer 36

683 msec

Question 37

Lower levels of muscle activity if _____ and ____ are coincident

Answer 37

MIP; CR

Question 38

How many times per day do we swallow?

Answer 38

Up to 700 times

Question 39

What is the first stage of swallowing?

Answer 39

- voluntary control - bolus of food is created - lips are sealed - tip rests against hard palate behind incisors - teeth contact in MIP - reflex reaction in tongue pushes food posteriorly into pharynx

Question 40

What is the second stage of swallowing?

Answer 40

- food bolus in pharynx - contraction of pharyngeal constrictor muscles move food to esophagus (peristalsis) - soft palate rises and seals off the nasal passages (nasopharynx) - epiglottis seals off trachea

Question 41

What is the velopharyngeal seal?

Answer 41

Soft palate rises and seals off the nasal passages (nasopharynx)

Question 42

What is the third stage of swallowing?

Answer 42

- peristaltic waves move food into the stomach (6-7 seconds) - cardiac sphincter relaxes and food enters stomach

Question 43

What is speech?

Answer 43

Controlled contraction and relaxation of the vocal cords as air is moved through the larynx

Question 44

When does speech occur?

Answer 44

During expiration

Question 45

Do the teeth contact during speech?

Answer 45

NO

Question 46

Since the teeth don't contact during speech, what can help determine?

Answer 46

A patients correct occlusal vertical dimension

Question 47

Where are the centric occlusion contacts?

Answer 47

Question 48

Where are the canine guidance contacts?

Answer 48

Question 49

Where are the group function contacts?

Answer 49