Treatment Planning Flashcards
What to check when doing a restoration?
Which teeth are in ICP, RCP and is the tooth involved in guidance?
Complete restoration
Now check ICP and RCP contacts against, protrusive and lateral excursions
Indirect restorations - Easier conformative cases?
Usually smaller no of units 1-2 units No guiding teeth No interferences Facebow not usually necessary
Indirect restorations - Reorganised cases?
Full mouth re-hab
Multiple restorations in multiple quadrants
When increasing vertical dimensions
What to do before and during preparation with easier conformative cases?
What to do during fit?
Assess contacts in ICP - Shimstock or GHM - Adjacent teeth - Contralateral side Assess RCP contacts Assess guidance in excursions Study casts
During prep ensure sufficient space for restorative material, check in ICP and excursions
Fit:
Check ICP, lat/protrusive excursion and adjust necessary
ICP - ensure tooth can hold shimstock paper, but also that all teeth with previous ICP contacts can hold shimstock
Excursions - Check excursions are the same as before and no interferences produced
When may you want to change the occlusion following a simple restoration?
Avoid excursive contacts on a restored cusp
Change an RCP contact point from a restored surface to natural tooth structure
To move an ICP contact point away from a restoration interface
To remove a non-working side interference
To reintroduce canine guidance
Loss of canine guidance can result in..?
How to prevent this?
Usually a result of tooth wear
Can transfer guidance posteriorly
= Non-ideal forces on lingual cusps of lower molars = fracture of cusp
Restoring tooth = fracture again
Canine guidance should be reintroduced first
How to restore canine guidance - simple restorations?
Usually an ICP contact on the canine = needs to be maintained
Form of the canine is altered to restore this tooth so it’s the only one involved in the working side excursion
Achieved using indirect restorations or direct composite
What makes a conformative case complex?
3+ units
Any unit if guiding
Difficult occlusions, especially:
- Class II div II - if restoring anterior teeth
- Class III/AOB - If restoring posterior teeth
Facebow needed
What can sometimes happen to the last tooth in the arch with simple conformative cases?
Situation develops when preparing last tooth in the arch
As you prepare the last tooth, when the pt bites together the teeth maintain contact and the space is lost
Occurs if last tooth is lone standing
Possibly occurs due to a shift in the condyles following tooth prep
How to prevent the last tooth in the arch from happening?
To prevent this the ICP contact point should be maintained following prep with an occlusal stop
= Removed by the technician when fabricating the crown
And needs to be removed on the tooth prior to fit
Don’t allow pt to bite down following removal of the stop as the pt will immediately adapt and the space will be lost
What to do before prep of a complex conformative case?
Udertake full occlusal analysis
U and L imps and facebow
Have casts mounted on articulator using facebow
Analyse mounted casts and check occlusal analysis
Decide if there are any aspects of the occlusion you wish to adjust
Get a wax up of the intended restoratons
Why use a facebow?
Records spatial orientation of the upper teeth relative to the condyles
= Allows correct positioning of upper model, lower model is mounted using interocclusal record
= Allows you to assess the casts in occlusion, with ICP, RCP, protrusive and lateral excursions as close as possible to pts occlusion
Allows lab to construct crown/bridge taking into account occlusion = less adjustment in clinic
Can customise guidance
What should teeth involved in guidance have in complex cases?
Suitable root structure
Enough remaining tooth structure
Ideally no endodontic post
What should bridgework in conformative complex cases aim for?
Contact in ICP on abutment tooth
Light contact in ICP on the pontic (shimstock just pulls through)
Avoid guidance on pontic, especially if cantilevered
Indirect materials - when to use?
Gold
- Suitable to be used in guidance
PFM
- Try to avoid ICP contacts on the interface
- Consider having metal on the guiding surface and occlusally for pts with heavy bites
Dentine bonded crown
- Gain strength from bonding to underlying tooth structure
- Try to avoid heavy/guiding contacts on individual teeth
High strength porcelain crowns:
- Should be able to withstand occlusal forces due to strength
- However, if a veneering porcelain has been layered on top for aesthetics = can fracture off
