Occlusion in RPD's Flashcards
Why is occlusion important in RPD’s?
If get it wrong the patient will not tolerate the denture no matter how well fits in the arch
How are RPD’s different to CD’s
The patient has natural teeth remaining which will influence:
The occlusion
The position of teeth
The occlusal plane
This has significant impact on the denture construction process from planning/design through delivery of the denture
What is ICP
The point of max intercuspation between the teeth - natural position
When is ICP stable?
If goes in to the same position each time dictated by the cusp form
When will you not have a stable ICP?
If grind teeth - have no cusps
What is centric relation?
Relationship of the mandible to the maxilla when the condyles are seated in the midmost uppermost position of the glenoid fossa
What does CR have nothing to do with?
CR has nothing to do with teeth, is a jaw relationship
Why do dentists you CR position?
Useful as it is reproducible and generally well tolerated by patients
What is the optimum position for neuromuscular system?
Centric relation
What is retruded contact position related to?
What is it?
Teeth
The first tooth contact when the condyles are fully seated in the glenoid fossa
Where is the usual first point of contact in CR?
Usually on a posterior tooth
Sometimes can have a couple of positions
What is vertical dimension?
Indicates the superior-inferior relationship of the maxilla and the mandible when the teeth are situated in max intercuspation
How does a stable ICP appear?
Clear intercuspation between numerous teeth which the patient consistently replicates
When is it more difficult to get into stable ICP?
When have fewer teeth present or if have tooth wear
Reducing the cusp heigh then dont have the same interlocking and ICP isnt clear
How to check is the ICP is stable?
Move the teeth laterally while in ICP
When will vertical dimension not be stable?
If have no occluding contacts - if the teeth dont oppoer each other
When may you need to increase the OVD?
IF posterior teeth over erupt - no longer have space to place opposing teeth
If patient has a stable ICP and acceptable vertical dimension what stage can you now go on to for mucosa and tooth borne dentures?
Mucosa- proceed to making a mucosa borne denture - design with study models
Tooth borne - consideration to the position of the occlusal rests consider articulating the models prior to designing
If patient has a unstable ICP and acceptable vertical dimension what stage can you now go on to for mucosa and tooth borne dentures?
Establish a new ICP to coincide with centric relation (as this is reproducible)W
Need to establish the new occlusal scheme on reg rims and articulate the models prior to designing
If patient has a stable ICP and unacceptable vertical dimension what stage can you now go on to for mucosa and tooth borne dentures?
Will need to use reg rims to establish a new ICP at the correct vertical dimension to be coincident with centric relation
If patient has no stable ICP and unacceptable vertical dimension what stage can you now go on to for mucosa and tooth borne dentures?
Need to use reg rims to establish a new ICP at the correct vertical dimension to be coincident to centric relation
When do you design the denture?
After primary imps or after articulated
What is needed to design the partial denture?
Surveyed and articulated study casts
Once designed the denture you can proceed to tooth prep and secondary imps
What should the rests seats ideally be like?
1mm deep, not into dentine with rounded edges
Dont forget to leave enough space for the minor connector or clasp arm
There needs to be enough space for the rest seats without it affecting the occlusion
What happens at the CoCr try-in stage?
Check the framework fits well on the cast and is fully seated
Then transfer to the mouth and ensure that the framework fully seats - paying particular attention to the rest seats
Check the occlusion
If required adjust until framework seats fully and doesn’t interfere with the occlusion
What is done at wax reg?
This will be on a wax/shellac/acrylic base for acryic dentures
This should be on the metal framework for the cobalt chrome denture
What does the wax reg stage confirm?
occlusal relationship, tooth position and incisal plane
What is done at fit?
Check there have been no changes to the occlusion from the wax try in stage
May any adjustments
Check record - double check occlusion
What is done at the review?
Make sure no changes and that patient is happy
When use metal backings?
Gives protection to anterior teeth, good for bruxists and heavy bite
Need to know the exact position of the teeth prior to the metal framework being made
Done after wax reg
What is the summary of the denture construction process
Primary imps Wax reg- of occlusion not obvious Tooth try-in - if metal backings required Design denture Tooth prep and secondary imps Framework try-in for CoCr Wax reg on CoCr Wax try in Re-try Fit Review
