Lecture 13- Determinants of Occlusal Morphology Part 2

Question 1

what do horizontal factors influence

Answer 1

the direction of the ridges and grooves on the occlusal surfaces and the placement of the cusps

Question 2

what happens in right mediotrusion

Answer 2

the right condyle moves medially

Question 3

what happens in right laterotrusion

Answer 3

the right mandible moves laterally

Question 4

what are the horizontal factors

Answer 4

-distance from the rotating condyle
-distance from the midsagittal plane
- amount of mandibular lateral translation
-intercondylar width

Question 5

what do horizontal factors effect

Answer 5

-effect of distance of the tooth from the rotating condyle and the midsagittal plane
- effect of mandibular lateral translation movement
- effect of intercondylar distance

Question 6

the greater the distance of the tooth from the rotating condyle the ____ the angle formed by the working and non working pathways

Answer 6

wider the angle

Question 7

the greater the distance of the tooth from the midsagittal plane the ____the angle formed by the working and non working pathways

Answer 7

wider

Question 8

most of the time teeth that are closer to the midsagittal plane will be at ____ distance from the rotating condyle

Answer 8

greater

Question 9

teeth that are positioned more anteriorly in the jaw tend to have greater _________ compared to teeth that are positioned more posteriorly

Answer 9

angles between mediotrusive and laterotrusive pathways

Question 10

the angle formed by the working and non working pathways increases as the amount of ____

Answer 10

lateral translation increases

Question 11

the direction of the lateral translation also influenes ____

Answer 11

the angle

Question 12

what is the effect of intercondylar distancr

Answer 12

the angle formed by the working and non working pathways decreases as the intercondylar distance increases

Question 13

what is another term for working interfering contacts

Answer 13

laterotrusive contacts

Question 14

what is another term for non working interfering contacts

Answer 14

mediotrusive contacts

Question 15

what makes up the physiology of the masticatory system

Answer 15

-mastication
-swallowing
- speech

Question 16

describe mastication

Answer 16

• initial stage of digestion
• rhythmic separation and closure of the teeth- control of the central pattern generator
• automatic/involuntary- can be controlled voluntarily

Question 17

what is the chewing stroke

Answer 17

single cycle of opening and closing

Question 18

what is the shape of the chewing stroke and what makes up the phases

Answer 18

-tear shaped pattern
- opening phase
- closing phase: crushing phase and grinding phase

Question 19

where does the chewing stroke begin and end

Answer 19

at MIP

Question 20

what would tall cusps and deep fossae indicate about the chewing stroke

Answer 20

more vertical chewing stroke

Question 21

most people have a _____ chewing stroke

Answer 21

preferred

Question 22

____ frequency of contacts as food is broken down

Answer 22

increased

Question 23

describe the tooth contacts during mastication

Answer 23

-gliding contact (cuspal inclines)
- single contacts (MIP contacts)

Question 24

what is the average length of time of tooth contacts in the chewing stroke

Answer 24

194 msec

Question 25

how do maximal biting forces vary

Answer 25

-male > female
- skeletal relationships and occlusion
-race (eskimos +++)
- anterior or posterior tooth
- mastication or swallowing

Question 26

what is the average max biting force

Answer 26

80-150 lbs

Question 27

are maximal biting forces stronger or chewing forces

Answer 27

maximal biting forces

Question 28

what are the maximal biting forces of dentures

Answer 28

1/4 that of the natural teeth

Question 29

what is the definition of swallowing

Answer 29

series of coordinated muscular contractions that move a bolus of food from the oral cavity through the esophagus to the stomach

Question 30

describe the swallowing reflex

Answer 30

voluntary/involuntary and reflex muscle activity
- somatic/visceral swallow

Question 31

what is the mandible stabilized by during swallowing

Answer 31

tooth contacts in MIP

Question 32

how long is tooth contact during swallowing

Answer 32

683 msec

Question 33

how is muscle activity affected during swallowing if MIP and CR are coincident

Answer 33

lower levels of muscle activity

Question 34

how many times a day do we swallow

Answer 34

up to 700

Question 35

describe what happens in the first stage of swallowing

Answer 35

• 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 36

describe what happens in the second stage of swallowing

Answer 36

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

Question 37

what happens during the third stage of swallowing

Answer 37

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

Question 38

what happens during speech

Answer 38

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

Question 39

when does speech occur

Answer 39

during expiration

Question 40

do teeth touch during speech

Answer 40

no

Question 41

what is speech used to determine in patients

Answer 41

correct OVD