Oral functions feeding Flashcards
The first part of the feeding sequence is ingestion . What does this mean?
- Movement of food from the external environment into the mouth
How is ingestion of food accomplished?
- By biting (anterior teeth) and/or using tools (cutlery, cups etc)
What do lips provide in ingestion of food?
- An anterior oral ‘seal’
What 2 muscles are used to control the food bolus and prevent spillage of food?
- Buccinator
- Orbicularis oris
What is meant by ‘transport’ of food in the mouth?
Moving material from the front of the mouth to the level of the posterior teeth
How is food moved from the front of the mouth to the level of the posterior teeth? (3 points)
- Food is gathered in tongue tip
- Tongue retracts, pulling the material to the posterior teeth (pull back process; takes about 1 second)
- Associated with retraction of the hyoid bone and narrowing of the oropharynx
What is meant by ‘mechanical processing’ of food in the mouth? (2 points)
- Some solid foods must be broken down and mixed with saliva before they can be swallowed
- Moist solid foods have to have fluid removed before transport and swallowing
What is used to chew foods?
- Premolar and molar teeth
How can some soft foods be mechanically processed in the mouth (not including teeth)?
- They can be ‘squished’ by the tongue against the hard palate
Food processing involves the co-ordinated actions of many muscles. What are the categories of these? (4 points)
- The ‘mandibular muscles’
- The supra-hyoid muscles
- The tongue muscles
- The lips and cheeks
What is the role of the tongue in chewing? (3 points)
- Plays a key role in controlling and transporting the food ‘bolus’ within the mouth
- Tongue gathers food and ro tates to reposition the bolus on the occlusal table
- Along with the cheeks, it keeps the bolus on the chewing surfaces
Why do we always encourage patients to chew bilaterally?
- As unilateral chewing is not advised and can cause problems in the masticatory system
- Might have hypertrophy of the masseter
What does the forward movement of the tongue during the occlusal and initial opening phases of chewing create and what mechanism does this create?
- Creates a contact between the tongue and the hard palate
- The contact zone moves progressively backwards, squeezing the processed food through the fauces - this is called the ‘squeeze mechanism’
Food accumulates on the pharyngeal surface of the tongue and remains there until swallowing occurs. What is the difference between swallowing solids and liquids?
- During processing of solid foods, the mouth is continuous with the oropharynx
- However, a posterior oral seal is produced during the ingestion of liquids
What are the 3 phases of the chewing cycle and what is the importance of studying this?
- Opening phase (jaw depressor muscles are active)
- Closing phase (jaw elevator muscles are active)
- Occlusal phase (mandible is stationary/teeth joined) (intercuspal position where teeth are together
Importance
- Cycle is different between people/dentition and between different foods
What is the chewing cycle like with brittle foods?
- Narrower
What is the chewing cycle like with tough foods?
- Wider
Occlusal conditions has a marked effect on the chewing stroke in a chewing cycle. What is the chewing cycle like of people with good, worn and malocclusion?
Good = closer together
Worn = More random and irregular
Malocclusion = there is no consistency
If a patient performs ruminatory mandibular movements what should you consider for the denture to achieve balanced occlusion?
- Consider teeth with cusps (especially where patients have a favourable ridge form)
If a patients denture has occlusal surfaces which are evenly worn (flat), what does this usually suggest?
- Usually suggestive of vertical (chopping) mandibular movements
- (cuspless teeth may need to be used)
Why must tongue movements be considered when designing prostheses?
- As inaccurate placement of mandibular posterior teeth might interfere with the tongue’s movements and will compromise the retention and stability of the denture
What does mechanical breakdown of food in the mouth facilitate? (2 points)
- Swallowing
- Might improve digestive efficiency in the GIT
Does all dentition need to be present for adequate chewing?
- No, minimum chewing with a ‘good’ dentition is sufficient to ensure adequate digestion of most foods
What does deterioration of masticatory performance result in? (3 points)
Results in dietary restrictions:
- Avoiding foods that are ‘difficult’
- Such as green veg and some meats
How many teeth are considered the minimum required to be acceptable for masticatory function, aesthetics and maintenance of oral hygiene and what is the name for this?
- 20 teeth
- The shortened dental arch
When are absent molar teeth replaced in the form of a partial denture?
- Only if their absence gives rise to problems
Does a shortened dental arch provide sufficient occlusal stability?
- Yes
Does a shortened dental arch provide satisfactory comfort and appearance?
- Yes
If a shortened dental arch exists, what must particular attention be given to?
- The possibility of simply maintaining the status quo rather than providing a RPD
Are biting forces reduced or increased in complete denture wearers?
- Reduced
What is the biting load of complete dentures carried by?
- The mucosa of the residual ridge
this is not designed to bear masticatory loads
How can the biting forces of complete dentures be increased?
By supporting dentures on teeth or implants
What are all the possible forms of replacement of missing teeth? (5 points)
Mucosa supported prosthesis:
- Complete
- Partial
Tooth supported prosthesis:
- Removable
- Fixed (bridges)
Bone supported prosthesis:
- Implants
What is a cantilever bridge?
- A pontic connected to a retainer at one end only
- It 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 are the benefits of an adhesive bridge/resin bonded bridge? (5 points)
- An immediate, temporary adhesive bridge is appropriate, followed by a permanent bridge once the tissues have settled
- They are quick, non-destructive aesthetic and durable (good life span)
What is another name for an adhesive bridge?
- Maryland
