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