RPD 2 Flashcards
What are spoon dentures used for
temporary
What are every dentures?
What are properties
Borders 3mm from the margins
Open design at saddle/tooth junction
Point contacts between abutment and artificial
Fanges includes to provide bracing
Posterior wire stops to prevent posterior drift and loss of contact
How are lateral stresses reduced in every dentures?
Balanced occlusion
What is included in the RPI system?
R = occlusal rest P = distal plane guide I = Gingivally approaching I-bar
When is the RPI system used?
For free-end saddle cases
What does the RPI system allow?
Minor connector and distal plate together act to provide reciprocation to the I-bar
Where should the I bar be placed in the RPI system?
Should be on or anterior to the midpoint of the buccal surface
What is the path of insertion?
Mechanical retention - relative to the path of displacement
Why consider creating guide planes?
when do it in particular?
To restrict the path of insertion
Particularly when providing musoca born RPD’s
How do you record a path of insertion?
3 marks with lead at fixed height
Scribe the side of model
Why may a shortened dental arch be necessary?
It is more important to maintain the teeth that remain rather than replacing the missing one
What does WHO say about a shortened dentition?
20 natural teeth throughout adulthood
Having a functional occlusion important
Why consider SDA over RPD?
RPD’s that replace molar teeth may not provide the patient with any immediate masticatory benefit
RPD’s often requiring patient to learn new skills to effectively use the appliance
A standard of OH is required is required by patient if further tooth loss is to be avoided
Patients may find this harder with an RPD
What are the disadvantages of SDA?
Increased risk of anterior tooth wear
RPD provision in future may be more challenging with fewer teeth, tongue space, controlling a larger denture
What’s the different combination work?
Milling a crown
Attachments
CoCr RPD/onlay - where space for acrylic teeth is limited, where increase in OVD
Telescopic crowns
What do undercuts need to be noted for?
Undercut for retention by creating a POI
Note undercut for retention for clasping
What are the roles of the dentist?
Assess patient TP Prep work Tooth prep Design partial denture Prescribe RPD Monitor denture in changing oral environment
What are the roles of clinical dental technician
Assess pt
TP with dentist
Design RPD with dentist
Construct RPD to prescription
Amend detail but not direction of the TP/prescription
Monitor denture in the changing oral environment
What is the undercut assessment necessary for?
For POI and POD
For clasping
For reciproction
What do you need to assess in the edentulous areas?
Size and position
Which are going to be saddle area
Is there room for teeth
Is tooth prep necessary to enlarge the gap?
What needs to be assessed on the occlusion?
Is there room for occlusal rest
What will happen on excursion
Is the ICP and OVD acceptable
What needs to be included on your prescription
Extension of saddles and number and size of tooth
Position of occlusal rests
Clasp types on which teeth and corresponding reciproction
Type of connectors and their extension
Colour of the acrylic base where important for acrylic
What are the different metal frameworks for RPD’s?
Most commonly cast Co-Cr
Historically Au
Ti alloy available
SLM production is rapidly developing
When planning a partial denture, if the patient has teeth remaining, what will this influence?
The occlusion
Position of the teeth
Occlusal plane
The number, condition and location of the remaining teeth has significant impact on the denture construction process from planning and design.
When do we work to centric relation?
Complete dentures; correct vertical dimension and unstable ICP
Why work in centric relation?
Jaw relationship, nothing to do with teeth
It is the optimum position for the neuromuscular system
Reproducible and tolerated well by patients
What is retruded contact position?
Related to the teeth
The first point of contact when the condyles are fully seated in the glenoid fossa
What is vertical dimension of occlusion?
The superior inferior relationship of the maxilla and the mandible when the teeth are situated in maximum intercuspation
What is a stable ICP?
Clear intercuspation between numerous teeth which the patient consistently replicates
What is an unstable or unclear ICP usually due to?
Reduced number of tooth contacts
tooth wear
ICP position not easy to replicate
When will vertical dimension not be stable?
If there are no remaining tooth contacts
If the remaining teeth do not oppose each other
The patient may be partially dentate in both arches or edentate in one arch
If have a stable ICP and acceptable vertical dimension what do you do
You can proceed to make a mucosa borne denture - designing with study models
For tooth borne dentures consideration must be given to the position of the occlusal rests
Therefore consider articulating the models prior to designing
If dont have a stable ICP but have an acceptable vertical dimension, what do you do
Need to establish a new ICP to coincide with centric relation.
Therefore you will need to establish the new occlusal scheme on registration rims and articulate the models prior to designing
If have a stable ICP and unacceptable vertical dimension, what do you do?
Here you will need to use registration rims to establish a new ICP at the correct vertical dimension to be coincident with centric relation
If you have no stable ICP and unacceptable vertical dimension, what do you do?
Here you will need to use registration rims to establish a new ICP at the correct vertical dimension to be coincident with centric relation
What is the procedure for a simple RPD
Primary imps -> design (survey denture) Tooth prep and secondary imps Registration Try in Fit Review
Tooth preparation tips:
If rest seats requires make sure these are cut to appropriate dimensions
There needs to be enough space for the rests withouot affecting the occlusion
Don’t forget to leave enough space for minor connectors or clasp arms
Ensure that rest seat preps are picked up well by the secondary impressions
What do you need to confirm in the wax registration stage?
Occlusal relationship
Tooth position
Incisal plane
What do you check at the fit stage?
Check there have been no changes to the occlusion from the wax try-in stage
Make any adjustments as required
Check record
What are metal backings?
Provide a co/cr denture with metal backings occasionally
if need one, need to do a tooth try-in at this stage to tell the technician where the denture teeth and metal backings need to be
