oral functions 3: feeding

Question 1

what is ingestion?

Answer 1

movement of food from external environment into the mouth
accomplished by biting (anteriors) and/or using tools
lips provide anterior oral seal

Question 2

which facial muscles help to control food bolus and prevent spillage?

Answer 2

orbicularis oris

buccinator

Question 3

what is transport?

Answer 3

moving material from the front of the mouth to the level of the posterior teeth

Question 4

what are the stages of transport?

Answer 4

food is gathered on tongue tip
tongue retracts, pulling the material to the posterior teeth
associated with retraction of the hyoid bone and narrowing of the oropharynx

Question 5

what is mechanical processing?

Answer 5

some foods must be broken down and mixed with saliva before they can be swallowed
moist foods eg fruit must have fluid removed before tx and swallowing

Question 6

how is food mechanically processed?

Answer 6

foods chewed (masticated) by premolar and molar teeth
some soft foods are squashed by tongue against hard palate

Question 7

what muscles are involved in food processing?

Answer 7

mandibular muscles
supra-hyoid muscles
tongue muscles
lips and cheeks

Question 8

what are the tongue actions in chewing?

Answer 8

tongue controls the bolus
tongue gathers food and rotates to reposition the bolus on the occlusal table
along with cheeks it keeps the bolus on the chewing surfaces
tongue moves bolus from side-to-side of the mouth
gathers for transport

Question 9

describe the tongue/cheek actions

Answer 9

tongue and cheeks act in a reciprocal manner to place the food on the occlusal surfaces of the teeth
tongue-pushing and cheek pushing cycles are observed

Question 10

describe the process of tongue -> oropharynx

Answer 10

material accumulates on the pharyngeal surface of the tongue and remains there until swallowing occurs
during process of solid foods, the mouth is continuous with the oropharynx
posterior oral seal may be produced during the ingestion of liquids

Question 11

where are liquids swallowed from?

Answer 11

mouth

-oral seal

Question 12

where are solids swallowed from?

Answer 12

oro-pharynx

-no oral seal

Question 13

what happens during swallowing?

Answer 13

moved rapidly through the hypopharynx past the laryngeal inlet

Question 14

what are the phases of the chewing cycle?

Answer 14

occlusal phase-mandible stationary, teeth joined
opening phase
-jaw depressor muscles are active
closing phase
-jaw elevator muscles are active

Question 15

what can cause variations in chewing cycles?

Answer 15

chewing on a brittle food (carrot) appears to create a broader stroke than chewing on cheese
chewing gum produces an even broader and wider chewing stroke
occlusal conditions has a marked effect on the chewing stroke

Question 16

when is chewing style considered in dentistry?

Answer 16

when designing prostheses

Question 17

what should you do if the px performs ruminatory mandibular movements to balance articulation?

Answer 17

use teeth w/ cusps to achieve balanced occlusion

-esp. when px have favourable ridge form

Question 18

what does dentures with flat (evenly worn) occlusal surfaces suggest?

Answer 18

vertical mandibular movements (chopping)

cuspless teeth may be used

Question 19

why are tongue movements considered when designing a prostheses?

Answer 19

inaccurate placement of mandibular posterior teeth might interfere with tongue’s movements and compromise the retention and stability of the denture

Question 20

why is mechanical breakdown (chewing) of food necessary?

Answer 20

facilitates swallowing

might improve digestive efficiency in GIT

Question 21

what is sufficient to ensure adequate digestion of most foods?

Answer 21

minimum chewing with a good dentition

Question 22

what can deteriorates masticatory performance result in?

Answer 22

dietary restictions

• avoid difficult foods
• eg green veg, meat
• no evidence poor mastication causes malnutrition in people with GIT disorders

Question 23

what is a shortened dental arch?

Answer 23

20 teeth considered the minimum for acceptable:

• masticatory function
• aesthetics
• maintenance of oral hygiene

Question 24

what is the shortened dental arch concept?

Answer 24

absent molar teeth are only replaced if their absence gives rise to problems
SDA provides sufficient occlusal stability
SDA provides satisfactory comfort and appearance
chewing and comfort not significantly enhanced by RPDs

Question 25

how does age affect the number of people who might have a functional SDA?

Answer 25

falls dramatically with age

Question 26

describe biting forces in complete denture wearers

Answer 26

reduced
biting load carried by mucosa of residual ridge
not designed to bear masticatory loads
support area reduced
-mucosa vs PDL
biting forces can be increased by supporting dentures on teeth for implants

Question 27

how can you replace missing teeth?

Answer 27

mucosa supported prosthesis
-complete 
-partial
tooth supported prosthesis
-removable
-fixed (bridge)
bone supported prosthesis (implants)

Question 28

what is a cantilever bridge?

Answer 28

a pontic connected to a retainer at one end only

used to replace single teeth and only one retainer is used to support the bridge

Question 29

when is a cantilever bridge not recommended?

Answer 29

when occlusal forces on the pontic will be heavy

Question 30

what is an adhesive bridge/resin bonded bridge?

Answer 30

an immediate, temporary adhesive bridge is appropriate, followed by a permanent bridge once the tissues have settled
-quick, non-destructive (conservative of tooth tissues) aesthetic and durable

Question 31

why is mucosa borne RPD not recommended?

Answer 31

occlusal load transmitted to bone via oral mucosa

Question 32

why is tooth borne RPD recommended?

Answer 32

occlusal load transmitted to bone via the rests and PDL