Oral Functions: Feeding Flashcards
What is ingestion and what is carried out by?
Movement of food from the external environment into the mouth
- Accomplished by biting (anterior teeth) and/or using ‘tools’ (cutlery, cups, etc)
- Lips provide anterior oral ‘seal’.
What facial muscles are used in ingestion and what do they do?
- Help to control food bolus and prevent spillage:
–Orbicularis oris
– Buccinator
What is transport and how is it carried out?
Moving material from the front of the mouth to the level of the posterior teeth
Food is gathered on tongue tip
- Tongue retracts, pulling the material to the posterior teeth (pull back process; takes about one second)
What anatomy is transport associated with
retraction of the hyoid bone and narrowing of the oropharynx
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
How is mechanical processing carried out?
- Foods chewed (or masticated) by premolar and molar teeth
- Some soft foods are ‘squashed’ by tongue against hard palate
What muscles are involved in food processing? (general groups)
– the “mandibular (former mastication) muscles”
– the supra-hyoid muscles
– the tongue muscles
– the lips and cheeks
What neck muscle is involved in chewing?
sternocleidomastiod
What are the actions of the tongue in chewing?
The tongue ‘controls’ the bolus
Tongue gathers food for transport and rotates to reposition the bolus on the occlusal table (from side to side)
Along with the cheeks, it keeps the bolus on the chewing surfaces
What are the intrinsic tongue muscles and what do they do?
alter shape
longitudinal
vertical
transverse
What are the extrinsic muscles and what do they do?
alter shape and position
genioglossus
hypglossus
palatoglossus
styloglossus
What is the reciprocal action of the tongue and cheeks?
The 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 during chewing.
What is the squeeze back mechanism?
During swallowing, the tongue presses food backward against the palate in a wave-like motion. This “squeeze-back” action helps push the food down your throat through the fauces.
What is the difference between swallowing solids and liquids?
Solid foods, the mouth is continuous with the oropharynx
Liquid foods, posterior oral seal is produced during the ingestion of liquids (liquids are swallowed from the mouth)
What are the 3 phases of the chewing cycle?
opening phase - jaw depressor muscles are active
occlusal phase - mandible is stationary, teeth are joined
closing phase - jaw elevator muscles are active
What strokes does a good occlusion create?
narrow and less broad
What strokes does chewing on hard food create?
broader and wider
What should be considered when designing prostheses?
chewing style
If dentures have occlusal surfaces that are worn (flat), what might be the cause?
vertical (chopping) mandibular movement
When designing the denture, what type of teeth might be used for flat atrophic mandibular ridges?
cuspless teeth
What does mechanical breakdown of the food in the mouth acheive?
–Facilitates swallowing
–Might improve digestive efficiency in G.I. Tract
Minimum chewing with a ‘good’ dentition is sufficient to ensure adequate digestion of most foods
What does deteriorated masticatory performance cause?
– avoiding foods that are “difficult”
– such as green vegetables, some meats
there is no clear evidence that poor mastication causes malnutrition in people with G.I. tract disorders especially with modern foods and methods of preparation.
What is the minimum amount of teeth required for a SDA (shortened dental arch)?
20 teeth is considered the minimum for acceptable:
– masticatory function
– aesthetics
– maintenance of oral hygiene
What does a SDA provide?
- 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 were not significantly enhanced by the provision of RPDs.
What should be done if a SDA is present?
particular attention must be given to the possibility of simply maintaining the status quo rather than providing an RPD.
What is the biting load carried by in complete denture wearers?
mucosa of residual ridge (not designed to bear masticatory loads therefore support area is reduced)
Where is the biting load carried to in dentate patients?
PDL
How can biting forces be increased in patients with dentures?
by supporting dentures on teeth or implants
What are the types of supports in replacing missing teeth?
- ‘Mucosa-supported’ prosthesis
– complete – Partial - ‘Tooth-supported’ prosthesis
– removable
– fixed (‘bridges’) - ‘Bone supported’ prosthesis (Implants)
What is an example of mucosa-supported prothesis?
acrylic partial dentures
What is an example of tooth-supported prothesis?
CoCr partial dentures
Bridges
What is a cantilever bridge and what is it used for?
- A pontic connected to a retainer at one end only
- Is used to replace single teeth and only one retainer is used to support the bridge.
- Not recommended when occlusal forces on the pontic will be heavy
What is an adhesive bridge/resin bonded/maryland?
dental prosthesis that replaces a missing tooth by bonding a pontic (artificial tooth) to the adjacent natural teeth using resin cement, without the need for extensive tooth preparation.
What are the advantages of an adhesive bridge?
Quick, non-destructive (conservative of tooth tissues), aesthetic, and durable (good life span)
What are the two designs of adhesive bridges?
cantilever
fixed-fixed
What is mucosa borne?
Craddock class 2
Occlusal load transmitted to bone via the oral mucosa NOT RECOMMENDED!
What is tooth borne?
Occlusal load transmitted to bone via the rests and PDL RECOMENDED
