Prosthetic Revision
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Transcript Prosthetic Revision
Prosthetics Revision
Clinical Steps
Dr Charles
Scola
July 2004
Prosthetics Revision
Last two weeks we studied:
Dentist / Patient expectations
The value of an old denture
A written denture treatment plan
RVD = OVD + FS
Copy Denture Technique
F/F Clinical techniques
Overdentures
Meeting their needs & expectations
What sort of patient are they?
Easy going or up-tight
Adaptable or precise
Accepting or demanding
Cooperative or difficult
Asses their attitude & personality,
This is very important in denture tolerance
NEVER promise what you cannot deliver !
Your Denture Treatment Plan
This is your written prescription or recipe
Without it you will get lost !
It applies to new or old denture users
Must be agreed with the patient
Keeps you on the right track
Is your record and defense, in case of later
problems or complaints
At every stage of treatment
Check your treatment plan
Remind your patient of the plan
Explain what you are doing today
Measure RVD & OVD
Look at the old dentures & compare
Observe the patient as they talk & smile
Remind the patient of the limitations
Vertical Dimension
RVD is always > OVD
RVD should remain constant
whether dentures are worn or not
Whatever treatment you do
OVD may be changed by you
All patients need FS, 2 – 5mm
Vertical Dimension
RVD
Freeway space
Vertical Dimension
0VD
Prosthetics Revision
Today we are going to
consider:
Partial Denture planning &
design
The clinical stages of partial
denture construction
Please read Dr Ulpee Darbar’s notes, these are very good !
Partial dentures often
grow up into full dentures- why ?
Partial dentures often grow up into
full dentures- why ?
Plaque
Caries, perio disease
Trauma
Abrasion, forced gingival recession, tissue
hyperplasia
Excessive forces
Worsens perio disease, bone loss, mobility
Partial dentures – yes or no ?
So before we rush to make a partial
denture, ask yourself:
Will it do more harm than good
Are there ‘safer’ alternatives
Have you explained all the ‘pros and
cons’ to your patient
Partial dentures need plenty of
maintenance, by you and the patient
Partial Dentures - Benefits
Appearance
Face, lips, smile, sexy
Function
Chewing, biting, gripping, tearing, kissing
? Helps remaining teeth
Spreads load, prevents tilting, over-eruption
? Prepares pt for full dentures
(Is this rather defeatist)
Partial Dentures - design
Must minimize plaque build up and allow pt to
maintain good oral hygiene
Needs to avoid soft tissue trauma
Should support and stabilize the remaining teeth
without producing excessive occlusal or tipping
forces
Avoid your partial denture becoming:
1. a ‘gum stripper’
2. an orthodontic appliance !
Partial Dentures - design
Retention
Stops the denture falling out
Suction, friction, muscular, mechanical (clasps etc)
Resistance or Support
Stops the denture being pushed in (gum stripper)
Tissue or tooth borne ?
Connectors
Joins the teeth, aids resistance & retention
Make it as patient-friendly as possible
Refer Dr Ulpee’s notes on clasps/ rest seats
Resistance or Support
Stops the denture being pushed in
A major cause of trauma to tissues !
Tissue or tooth borne - Which is better?
Teeth are made to take occlusal load
Soft tissues are not !
The effects of ‘sinking’ are:
Trauma to gingivae and forced recession
Damage to mucosa by flanges and connectors
Denture teeth start to look too short
Natural teeth may be tilted, intruded or loosened
Providing Resistance or Support
Bring the acrylic up over the cingulum of
anterior teeth,...if the bite allows it !
✔
✖
Providing Resistance or Support
Bring the acrylic up over the bulbosity
of molars, ....if the bite allows it !
✔
✖
Providing Resistance or Support
You may need to cut a rest seat
Providing Resistance or Support
Provide metal occlusal rests
With premolars & molars you cannot easily
bring the acrylic over the occlusal surface,
..but you can fit a metal occlusal rest
Your denture
will ‘hang’ off
the teeth
Providing Resistance or Support
Occlusal rests;
Make the denture ‘tooth borne’
Should be used wherever possible
Are used on ‘strong’ teeth
Need to be positioned carefully
Can be formed from stiff wire and inserted
into the arylic
Providing Resistance or Support
You may need to cut a rest seat
Providing Resistance or Support
You may need to cut a channel for a clasp
This will also provide support
Connectors
Do not ‘pinch’ the gingivae
Keep 4mm away
Do not cause food traps
Cross the gingival margins mid-tooth only
Keep the design simple
Avoid cutting across rugae in palate
Follow them instead
Follow anatomical lines if possible
Partial Dentures - planning
As soon as you have your study models, and
BEFORE you take your 2’ impressions:
Plan your design, considering all the pros & cons,
and your patient’s wishes
You may need to consider:
More extractions
Hopeless prognosis, deep undercuts
Conservation
Reshape opposing teeth,
Cut rest seats, channels for clasps, guide planes
Remove undercuts, create undercuts
Guide Planes & Occlusal Rests
Partial Dentures
Lets try to design a few
Follow these principles:
Which teeth are to be replaced
Design connectors and outlines
Avoid palatine papilla if possible
Consider undercuts & path of insertion
Provide resistance & retention
Do any teeth need cutting, reshaping, or exo
Draw on your model & write your treatment plan
Partial Dentures, 2’ Imps
Check your treatment plan
Cut or reshape any teeth as needed, ?undercuts
Check your special tray covers all areas that are
crucial to your design
Take good alginate impressions, use your finger
Take your shade
Check the occlusion, ? take a wax bite, you may
not need to take MMR using bite blocks
Partial Dentures, MMR
Will only be needed if:
Many teeth are missing
There are free end saddles
There is no tooth to tooth contact
The existing occlusion needs to be raised,
or changed in some way (rare)
Partial Dentures, MMR
Check fit and stability of wax blocks
Trim occlusal levels to follow natural teeth
If there is tooth to tooth contact, use this
occlusion unless there is a specific reason
to change it
Record bite blocks in centric occlusion
Mark centre lines
Partial Dentures, Try - In
Confirm smile lines and levels
Agree aesthetics with the patient
Similar steps to F/F try in:
Assess accuracy of the occlusion
But also:
Check resistance –
Check retention Hygiene –
Soft Tissues –
is occlusion affected
will clasps show
are there food traps
any risk of trauma
Partial Dentures, Fitting
Try them in gently, never force them
Adjust carefully to ensure a snug fit
Check occlusion, ? Tooth to tooth contact
Check aesthetics, ? Objectives achieved
Ensure comfort, no trauma
Teach patient how to fit and remove them
Don’t use clasps as ‘handles’
Give full cleaning & maintenance instructions
Don’t wear them 24 / 7, give your mouth a rest
Prosthetics Revision
Today we have reviewed:
Partial Denture planning &
design
The clinical stages of partial
denture construction