Mastication

What is the role of mastication

breakdown of food

preparation for swallowing

stimulation of salivary flow

growth and maintenance of oro-facial tissues

what teeth do we need to have a functional occlusion

5-5

Mechanics of mastication

* lip movements
* jaw movements
* tongue movements
* cheek movements

what are the phases of the chewing cycle

* opening
* fast closing
* slow closing
* intercuspal phases

how long does 1 chewing cycle take

0\.5 - 1.2 secs

in what phase of the chewing cycle does food breakdown occur

slow closing + intercuspal

what are the movements of the condylar head during opening

Working side

* rotates around vertical axis
* moves 1-1.4,, laterally - Bennett Movement
* very slight posterior movement

Non - working side

* moves downwards, forwards and medially over articular eminence
* Described by Bennett Angle

movements of the condylar head during closing

Working side

* moves medially to normal position in glenoid fossa
* rotates back to normal orientation

Non-working side head

* moves upwards, backwards and laterally
* returns to normal position in glenoid fossa

what is the sequence of muscle activation during the chewing cycle

Opening

* mylohyoid
* digastric
* lateral pretygoid

Closing

* temporalis
* masseter
* medial pterygoid