What is occlusion? Flashcards
what can occlusion be defined as
contacts between teeth
how can the definition of occlusion be refined
defining those contacts between the teeth when the mandible is closed and stationary as the static occlusion, and those contacts between teeth when the mandible is moving relative to the maxilla as the dynamic occlusion
what are other names for centric occlusion
intercuspation position, bite of convenience or habitual bite
what is centric occlusion
is the occlusion the patient makes when they fit their teeth together in maximum intercuspation
what is centric relation
jaw relationship and describes a conceptual relationship between the maxilla and mandible
how can centric relation be described anatomically
It can be described as the position of the mandible to the maxilla with the intra-articular disc in place, when the head of the condyle is against the most superior part of the distal facing incline of the glenoid fossa.
what is the terminal hinge axis
two terminal hinge points are connected by an imaginary line called the terminal hinge axis
describes how the mandible opens
The mandible opens by firstly a rotation of the condyle and then a translation which is downwards and forwards
what is the terminal closure of the mandible
purely rotational
what is freedom in centric
another aspect of the static occlusion and it is the freedom in centric occlusion which occurs when the mandible is able to move anteriorly for a short distance in the same horizontal and sagittal plane while maintaining tooth contact
when will there not be freedom in centric
There will be no freedom in centric occlusion if either the front teeth or the posterior occlusion do not allow this horizontl movement
what is dynamic occlusion
refers to the occlusal contacts that are made whilst the mandible is moving relative to the maxilla.
what is the mandible moved away by
he muscles of mastication and the pathways along which it moves are determined not only by these muscles but also by two guidance systems
what is the posterior guidance system of the mandible provided by
TMJ
what is the guidance pathway determined by
the intra-articular disc and the articulatory surfaces of the glenoid fossa, all of which are enclosed in the joint capsule.
what is guidance
If teeth are touching during a protrusive or lateral movement of the mandible then those (touching) teeth are also providing guidance to mandibular movement.
what is canine guidance
refers to a dynamic occlusion that occurs on the canines during a lateral excursion of the mandible. A canine protected occlusion refers to the fact that the canine guidance is the only dynamic occlusal contact during this excursive movement
what is group function
contacts are shared between several teeth on the working side during a lateral excursion. The working side is the side of the mandible towards which the mandible is moving.
what is needed to qualify for group function
the contacts would need to be towards the front of the mouth and the most anterior needs to have the earliest and hardest contacts
what is working side interference
Working side interference means a heavy or early occlusal contact towards the back of the mouth during an excursive movement
what is non working side interference
is an anterior guidance on the back teeth on the non working side during lateral excursion
what is posterior interference
osterior interference are therefore considered to be a less ideal type of dynamic occlusion and the term ideal relates to whether or not it is ideal for another part of the articulatory system, the TMJ
what is the definition of ideal occlusion
- The coincidence of centric occlusion in centric relation (CO=CR), when there is freedom for the mandible to move slightly forward from that occlusion in the same sagittal and horizontal plane (freedom in centric occlusion)
- When the mandible moves there is immediate and lasting posterior disclusion (anterior guidance on front teeth)
