Intro to occlusion Flashcards
What is occlusion?
How the teeth come together and function
Whenever we do a restoration what should we keep in mind regarding occlusion
We need to make sure the patients but feels comfortable
What can happen if the teeth don’t meet in harmony?
Can lead to :
- Pain
- Loosening of teeth
- Fracture of restorations
What things can go wrong with occlusion?
We can overload the teeth
What can lead to overloading of teeth?
- Premature contacts (Interference)
- Lateral forces in posterior teeth
- Excessive forces due to parafunction (Bruxism)
What are occlusal interferences?
Interferences when a patent is bitting up and down usually due to a too high restoration
Define occlusion
The relationship of the maxillary to the mandibular teeth at rest and in function
What technique can you use to check you restoration isn’t too high?
Fremitus and articulation paper
What does Fremitus rely on?
Vibrations in the tooth
If a restoration is too high that tooth will vibrate more than its neighbours
What symptoms will a patient experience if you place a restoration that is too high?
- Inflammation
- Pain in the PDL
- Bruising + pain
- Widening of the PDL
- Increased mobility of tooth
Which forces are posterior teeth designed to deal with?
Vertical forces NOT horizontal
What is bruxism?
Subconscious, non-functional grinding
What symptoms can patents with bruxism experience?
- Increased tooth wear
- Fracture of restorations
- Muscle pain
- Micro cracks
What is the function of the Articular emine?
It guides the mandible forward when you slide you jaw forward
Where is the Articular emine found?
It is found on the glenoid fossa
What is freeway space?
The space between the upper and lower teeth AT REST
What is the typical value of the freeway space?
2-4mm
What does ICP stand for in terms of occlusion?
Inter cuspal position
What is the Intercuhspal Position?
The position of he mandible when the mandibular and maxillary teeth are maxillary interdigitated
What does RCP Stand for?
Retruded Contact Position
What two processes occur in the TMJ when the mouth opens?
The condyle both ROTATES and TRANSLATES (moves forwards and downwards)§
What is the first part of rotation (jaw opening) controlled by?
The digastric muscle
Up to how many cm does the mouth open during rotation?
Upto 2cm (20mm)
Which muscle controls the translation of the mouth?
Lateral pterygloid muscle
What happens in the translating stage of jaw opening?
The jaw open all the way
Name the key muscles involved in closing the mouth
- Temporalis
- Masseter
- Medial pterygoid
- Lateral pterygoid
Name some jaw movements we talk about in dentistry
Protrusion and lateral movements
How does your body prevent horizontal movement form affecting the molars?
Condylar guidance
What is the “working” side
The side your jaw is moving to
What is the non working side?
The side your jaw isn’t moving to
Which sides condyle moves more?
The n on working side
What are the 2 terms we use to describe occlusal schemes
- Canine guidance
2. Group function
Describe a patient who is said to have canine guidance
It means only the canines on their working side remain in contact when movies to that side
Describe a patient who is said to have group function
When they move their jaw laterally 2 or more teeth remain in contact on the working side
Why might older patients be in group function rather than canine guidance
Because over time they have worn down their canines due to grinding
What are the problems associated with group functions
Canines come into contact with each other during lateral movement which they don’t like
What can we use to check the occlusion of alginate models we have taken?
We can use an articulator
What is an articulator?
It is a mechanical device that recreates the patients jaws upon which study models can be positioned and the relationship between upper and lower teeth can be studied
Name different types of articulators
- Simple hinge
- Average value
- Semi adjustable
- Fully adjustable
What is the terminal hinge axis
The point about which the condyle rotates during the rotatory phase of opening
