Mandibular Movements Flashcards
What cusp of the mandible molar teeth are normally seated in the central fossa of maxillary molars?
Distobuccal
What do the palatal cusps of the maxillary bicuspids contact?
Contact the marginal ridges of mandibular bicuspids and 1st molar
What cusp of the maxillary molars are seated in the central fossa of the mandibular molars?
The mesiopalatal
In intact unworn teeth where are the actual contact points?
Called centric stops or holding contacts, because they serve to hold the teeth in a stable position
The supporting cusp contact the opposing inclines leading tip the fossae - ideally with a buccal and lingual contact for each cusp
What are the actual contact points called?
Centric stops or holding contacts
What are the contact points of intact supporting cusps?
Contact on inclines leading the the central fossa with a buccal and lingual contact for each group
They have at least 1 mesial or distal contact with opposing marginal, triangular, transverse or oblique ridges
How many contacts allows the firm position of a supporting cusp?
At least 3
What are the contacts of supporting cusps called?
Tripodisation or tripodism of posterior occlusal contacts
What are the 2 main types of anterior guidance in lateral excursion?
Canine guidance
Group function
What guidance is involved in protrusion?
Incisor guidance
Describe Invisalign guidance
In protrusion the mandibular incisal edges glide down along the palatal inclines of the maxillary incisor teeth
What side are the condylar and bennet angles measured?
Non-working side condyle
What is the condylar or bennet angle?
The angle down the saggy tail plane and horizontally towards the working side
What is a condylar movement?
The immediate non-progressive side shift it immediate side shift or bennet movement
The movement of the working side condylar head outwards (laterally) during lateral excursion
Describe the condylar movement?
This movement is immediate and non-progressive
Why does immediate side shift happen?
It is the effect of downward, forward and inward movement of the non working side condyle during lateral excursion
What is the condylar angle?
The angle formed by the downward movement of the non working condyle to the horizontal plane
What is the general condylar angle?
22-65
Usually around 30
What is the Bennet angle?
The angle formed from the medial movement of the non working condyle to the vertical plane
What is the Bennet movement?
Forward downward and inward translation and the rotation of the working side
Working side condyle moves laterally in the direction of the lateral excursion and sometimes slightly downwards. This bodily lateral shift of the mandible is called the bennett movement
What is the average shift of the bennet movement?
1.5mm
Can the Bennet angle exist even in the absence of the Bennet movement?
Yes
What is the centric relation?
Position of the mandible to the maxilla with the intra-articulation disc in place, when the head of the condyle is against the most superior part of the distal facing incline of the glenoid fossa
I.e the condyle is in the uppermost and foremost position within the glenoid fossa
What is posselt’s envelope of movement?
Gives an idea of the different movements of the mandible
On the saggital plane
