Tooth wear and occlusion Flashcards
What are the parts of the articulatory system
Temporomandibular Joints (TMJs)
Occlusion
Muscles of Mastication
What does the study of occlusion take into consideration
The close interrelationship between
the articulation of the teeth and the muscles of mastication and TMJ
What are the types of occlusion
Static and dynamic
What does static occlusion involve
Centric Occlusion (CO)
Habitual Bite
Maximum Intercuspation (MIP)
Intercuspal Position (ICP)
All terms for teeth fitting together
What does dynamic occlusion involve
Mandibular Eccentric Movements
Lateral Excursion
The sideways movement of the mandible from a centric position
How can we mark the occlusal contacts
Occlusal analysis armamentarium
Articulating papers held by miller forceps
Why are different colours of
papers used in marking occlusal contacts
For identifying specific tooth contacts and to allow comparisons to be made
What holders can be used for articulating papers
Miller forceps
Y-type articulating holder
Fix-clip bite frame
What is the benefit of a bite-chek articulating film
Bite-Chek with its easy-grip handle,
requires no forceps, simplifing
checking the occlusion.
*There is no risk of biting forceps.
*No curling, handle hold the film flat.
*Handle keeps the gloves clean.
*Thin 19 micron film marks high points
accurately.
*Available in double-sided Black/Black or
Black/Red
Why are thin papers used to show occlusion
To minimise contacts artefacts and clearly indicate tooth contact detail
Thick paper will mark a large area surrounding the point of contact and result in grinding of unnecessary tooth
Why might ICP contacts be broad and rubbing
There may be underlying occlusal problems
What does a large ring on colour with a much lighter internal segment indicate in occlusion
The lighter section is where the actual occlusion occurs while the surrounding area is from the high pressure squeezing out extra pigment
What are wear facets
A type of non-carious lesion that
occurs when teeth rub against each other too much
What are the supporting cusps in occlusal stability
Mandibular buccal
Maxillary palatal cusps
What may excess colour from articulating papers indicate
Premature contact due to a high point on the tooth which will be more prone to fracture and should consider altering this
What are the non-supporting cusps
Mandibular lingual
Maxillary buccal
What causes axial loading
Reciprocal incline contacts (tripodization)
How many reciprocating contact areas does each centric cusp have in relation to the opposing fossa in tripodization
3
Where should the occlusion from a cusp be
On a fossa or marginal ridge for stability
If a cusp only has a single contact with an opposing tooth what can occur
Allows for unwanted tilting and overeruption
When should tripodization be used
When contact point of the cusp cant be in line with the fossa so tripodization is the next best option
What can cause a mediotrusive contact
The new posterior restoration has been
overcarved, resulting in a lack of contact with the mandibular buccal cusp
After a time the mandibular tooth shifts to a more stable occlusal position, which
re-establishes contact between the mandibular buccal cusp and the restoration
Although the ICP is now stable, a
mediotrusive contact has
resulted
Why should occlusal contacts on tooth-restorative interface be avoided
Dental restorative materials, while durable, may not withstand the full force of occlusion over time as well as natural tooth enamel. Excessive pressure can lead to
material fracture or debonding
What is T scan
A digital tool used to analyse occlusal forces.
It provides a detailed understanding
of the patient’s bite and how their
teeth come together
How can we detect the infra-occluded restoration
Shimstock is used to check firmness of occlusal contacts in
comparison with those on the selected index teeth
What is the thickness of shimstock
8 microns
What is group function
Multiple contact relations between
the maxillary and mandibular
teeth in lateral movements (Canine
are included)
What is canine guidance
The lower canines guide the mandible during lateral excursions of the jaw
This means that when the jaw moves to the side, the contact between the upper and lower canines prevents the posterior teeth from touching
How can we check that a new crown fulfils proper occlusion
The shimstock is still held after restoration as it did in between the natural teeth
When is occlusion improtant
Reduce Risk of Fracture/wear/ Failure
- Tooth
- Restoration
What should be remembered when placing or adjusting restorations considering occlusion
The periodontal ligament able to detect materials between teeth down to half the thickness of human hair
What is the ‘conformative’ approach
Consideration of the occlusal scheme is made according to the patients existing intercuspal position, and new restorations are provided in harmony with the
existing jaw relationships
How are dental loupes beneficial in occlusion
The use of loupes will facilitate removal of excess and reduce the risk of damage to marginal enamel
Allows a better working posture of <25 degrees avoid bending over the oral cavity
