Define ingestion
Movement of food from the external environment into the mouth
List how food is transported from the front of the mouth to the posterior teeth (3)
- Food is gathered on tongue tip
- Tongue retracts, pulling the material to the posterior teeth (takes 1 sec)
- Associated with retraction of the hyoid bone and narrowing of the oropharynx
How is mechanical processing of food achieved? (2)
> Foods masticated by premolar + molar teeth
> Some soft foods are ‘squashed’ by tongue against hard palate
List muscles involved in food processing (4)
- Mandibular muscles
- Supra-hyoid muscles
- Tongue muscles
- Lips + cheeks
Function of tongue when eating?
Controlling and transporting the food bolus within the mouth
List the tongue actions involved in chewing (3)
- Tongue controls bolus to keep it on the chewing surfaces, along with the cheeks
- Tongue moves bolus from side to side of the mouth
- Tongue gathers the bolus for transport
What happens in the initial opening phase?
The forward movement of the tongue during the occlusal and initial opening phases creates a contact between the tongue and the hard palate
What happens in the squeeze back mechanism/
The contact zone moves progressively backwards, squeezing the processed food through the fauces
When does the food accumulated on the pharyngeal surface of the tongue move?
Moves when swallowing occurs
List the 3 chewing cycle phases
- Opening phase
- Jaw depressor muscles are active - Closing phase
- Jaw elevator muscles are active - Occlusal phase
- Mandible is stationary/teeth joined
Chewing on a carrot variation in chewing cycle
Creates a broader stroke than chewing on cheese
Chewing gum variation in chewing cycle
Creates an even broader and wider chewing stroke
Define balanced articulation
Using teeth with cusps to achieve balanced occlusion
When is balanced occlusion used? (2)
- If the patient performs ruminatory mandibular movements use it to stabilise their dentition whilst they chew
- Especially where the patients have a favourable ridge form
What test is used to determine whether the patient may need balanced occlusion for complete denture patients?
- In complete denture patients we give them a biscuit to see how they chew (if there’s small movements consider an alternative)
- If they have lateral movements then consider balanced occlusion (if they don’t, use cuspless teeth)
What sign suggests vertical (chopping) mandibular movements
If the dentures have occlusal surfaces which are evenly worn (flat)
What type of teeth are used for patients that have worn occlusal surfaces
Cuspless teeth might be used (especially in flat atrophic mandibular ridges)
Why is tongue movement an important consideration before designing prostheses (2)
Inaccurate placement of mandibular posterior teeth might interfere with tongue’s movements
- Compromising the retention and stability of the denture
Where should the prosthesis be positioned
- Must be on the ridge, not lingually or buccally inclined
What can a buccally inclined prosthesis lead to
Cheek biting
Why would a neuromuscular disorder lead to a failed prosthesis?
Patient won’t have mechanical retention to control the denture with their tongue
Tongue sign of a successful prosthesis
If the tongue is raised to contact the denture then very good muscular control
Function of mechanical breakdown of food in the mouth (2)
- Facilitates swallowing
2. Might improve digestive efficiency in GI tract
What can deteriorated masticatory performance lead to?
Dietary restrictions
- Avoiding foods that are difficult
