Feeding - chewing and chewing performance Flashcards
3 feeding sequence components
ingestion
stage I transport
mechanical processing
ingestion is
movement of food from the external environment into the mouth
how is ingestion accomplished
by biting (anterior teeth) and/or using ‘tools’ (cutlery, cups, etc)
Lips provide anterior oral ‘seal’.
What muscle is involved in controlling this seal?
Orbicularis Oris
and buccinator control food bolus and maintaining seal
what provide the anterior oral seal
lips
stage I transport is
Moving material from the front of the mouth to the level of the posterior teeth
steps in stage I transport
Food is gathered on tongue tip
Tongue retracts, pulling the material to the posterior teeth (pull back process; takes about one second).
associated with retraction of the hyoid bone and narrowing of the oropharynx, in order to keep mastication effective before swallowing
what bone retracts in chewing?
hyoid bone
what is mechanical processing
Some solid foods must be broken down and mixed with saliva before they can be swallowed
Moist solid foods (e.g. fruit) have to have fluid removed before transport and swallowing
Some soft foods are ‘squashed’ by tongue against hard palate (involved)
what teeth are involved in chewing?
premolars and molars
sometime squashed against hard palate by tongue
what muscles are involved in food processing
o the “mandibular muscles”
o the supra-hyoid muscles
o the tongue muscles
o the lips and cheeks
what is the role of sternocleidomastoid
turning head from side to side and flexing neck
tongue key role
controlling and transporting the food ‘bolus’ within the mouth.
extrinsic tongue muscles
are involved in altering the shape and position of muscles
intrinsic tongue muscles
alter the shape
what does the tongue do when food initially enters the mouth
gathers food and rotates to reposition the bolus on the occlusal table
how does the tongue and cheeks work together
cheeks act in a reciprocal manner to place the food on the occlusal surfaces of the teeth.
- “Tongue-pushing” (red) and “cheek-pushing” cycles (blue) are observed during chewing.
(they keep the bolus on the chewing surfaces)
Helps in crushing bolus and effective chewing
how does the tongue move the bolus
from side to side of mouth
style of chewing
bilateral
issue with unilateral chewing
unilateral chewing can develop mandibular muscle problems
- can tell by symmetry of face,
- hypertrophy of masseter muscle on Extra oral examination
how is the contact between the tongue and hard palate created initially
forward movement of the tongue during the occlusal and initial opening phases creates a contact between the tongue and the hard palate.
how does the contact zone of the bolus with the tongue and hard palate move
moves progressively backwards, squeezing the processed food through the fauces
- the so-called ‘squeeze-back’ mechanism
squeeze back mechanisms
contact zone (bolus, tongue, hard palate) moves progressively backwards, squeezing the processed food through the fauces
where does the bolus accumulate before swallowing occurs
on the pharyngeal surface of the tongue
what is the oropharynx like during the processing of solid foods
continuous with the oropharynx
what is the oropharynx like during the ingestion of liquids
posterior oral seal produced
liquids are swallowed from the mouth .i.e without Stage II transport
what are the phases of the chewing cycle
Phase 1: Opening
- jaw depressor active
Phase 2: Closing
- jaw elevator active
Phase 3: Occlusal
-Mandible is stationary/ teeth joined
phase 1 of chewing cycle
opening
jaw depressor active
phase 2 of chewing cycle
closing
jaw elevator active
phase 3 of chewing cycle
occlusal
mandible is stationary/ teeth joined
brittle food variation in chewing cycle
narrower
e.g. carrot
tough food variation in chewing cycle
wider
e.g. meat
cheese, carrot and gum differences in chewing cycle strokes
Chewing on a carrot appears to create a broader stroke than chewing on cheese
Chewing gum produces an even broader and wider chewing stroke
what does a good occlusal condition do to chewing stroke
chewing stroked are close to each other
what does bruxism/ tooth wear do to chewing stroke
chewing strokes are random and wide
whats does malocclusion do to chewing strokes
no consistency
ruminatory mandibular movements
lots of lateral movement when chewing
how to achieve balanced articulation in prothesis in a patient who has ruminatory mandibular movements
use teeth with cusps to achieve balanced occlusion (especially where patients have favourable ridge form, be stable while they chew)
how to assess how a patient chews for a prothesis
assess how they chew a biscuit
vertical (chopping) mandibular movements lead to
worn (flat) occlusal surfaces
how to achieve balanced articulation in prothesis in a patient who has vertical (chopping) mandibular movements
cusp-less teeth
especially in flat atrophic mandibular ridges
what can inaccurate placement of mandibular posterior teeth on prosthesis lead to?
interference of tongue’s movement and compromise the retention and stability of the denture
how to ensure prosthesis teeth will not interfere with tongue space
ensure teeth are alligned on the ridge
when does a patient have neuromuscular denture control
when there is a resorbed maxilla and mandible
-no ridge
what is neuromuscular prosthesis control
Use tongue to control denture when biting
when would a patient not be able to have neuromuscular denture control
If they have neuromuscular disorder will not have this mechanism
Assess how they walk
what does mechanical breakdown of food in the mouth lead to
o Facilitates swallowing
o might improve digestive efficiency in G.I. Tract
what is minimum chewing with a good dentition sufficient to ensure
adequate digestion of most foods
what can deteriorated masticatory performance lead to
dietary restrictions
avoiding foods that are “difficult”
- such as green vegetables, some meats
what is there no clear evidence to indicate of poor mastication
causes malnutrition in people with G.I. tract disorders especially with modern foods and methods of preparation.
No adverse effects on health
what is the functional occlusal area like compared to the occlusal surface area
usually smaller than the total occlusal area (green outline), unless there is a lot of tooth wear
how many healthy units are considered the minimum acceptable
20 healthy units
what does 20 healthy units ensure (3)
masticatory function
aesthetics
maintenance of oral hygiene
what does ‘healthy’ in a healthy unit mean
good perio condition
no gross caries
what do you need to do if a patient does not have 20 healthy units
restore or provide RPD
when should you replace teeth
only replaced if their absence gives rise to problems.
3 things a Shortened Dental Arch provides
sufficient occlusal stability.
satisfactory comfort
satisfactory appearance
if a SDA exists what must be given attention
possibility of simply maintaining the status quo rather than providing an RPD.
- need to do work to maintain teeth
Need good attender, good oral hygiene – assess patient
correlation of number of people with functional SDA with age
fall dramatically with age
why are biting forces reduced in people with complete dentures
lack of periodontal mechanoreceptors
Biting load carried by mucosa of residual ridge
- not designed to bear masticatory loads
Support area is reduced (mucosa vs. PDL, no mechanoreceptors)
how can bite force be increased in patients with prosthesis need
supporting dentures on teeth or implants
replacing missing teeth in mucosa supported prosthesis
complete or partial denture
replacing missing teeth in tooth supported prosthesis
removable (have occlusal rests)
fixed (bridges)
replacing missing teeth in bone supported prosthesis
implants
acrylic partial denture (mucosa supported prosthesis) disadvantage
Not definitive treatment option of replacement of missing teeth
Temporary or transitional
- clasp is on gingival margin, gum stripper, sink on mucosa cause gum recession
- lacks support no occlusal rest seats
- force on bone and bone resorbs
cobalt chrome partial denture (tooth supported prosthesis) support is
on occlusal surfaces and cingulums (rests)
bridges are
(tooth supported prosthesis)
prepared teeth with pontic inbetween
fixed-fixed bridges (tooth supported prosthesis)
all ceramic
retainers with joining pontics
cantilever bridge (tooth supported prosthesis)
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
when is a cantilever bridge not recommended
when occlusal forces on the pontic are heavy
adhesive/ resin bonded/ maryland bridge (tooth supported prosthesis)
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 (good life span)
Least destructive
- Wing-pontic-wing from palatal aspect of teeth
- Stuck with adhesive material (composite) on the palatal side – no whole retainer teeth
advantage of adhesive/ resin bonded/ maryland bridge
Least destructive
- Wing-pontic-wing from palatal aspect of teeth
- Stuck with adhesive material (composite) on the palatal side – no whole retainer teeth
occlusal load transmission from RPD of mucosa born prosthesis
Occlusal load transmitted to bone via the oral mucosa, to mucosa and bone
- Bone resorbed
NOT RECOMMENDED
occlusal load transmission from RPD of tooth born prosthese
Occlusal load transmitted to bone via the rests and PDL to PRDL and bone
- Greater distribution and dissipation of forces
- Less resorption
RECOMENDED
why is tooth preparation needed for RPDs
to create rest for support in CoCr RPD
implants not indicated for use if
Systemic disease, diabetes - affect healing
Smoker – not NHS implants, effects osteointegration of implant
advantages of implants
Bone supported (best) - screws/fixtures will bare forces
Fixed (permanent change patient life and appearance)
-Aesthetically acceptable and functions well
