Planning for Crowns and Bridges

Question 1

A plan should be

Should inform patient about

Answer 1

Discussed in detail

Current conditions
Extent of tx
Time and cost
Level of home care
Level of maintenance/repairs and replacements
Possible alterations before irreversible changes are made

Question 2

Identifying patient needs

Answer 2

Correct existing disease
Prevent future disease - INDICATIONS 
Restoration of function 
Improve appearance 
Treatment plan should conform to the patient's needs not to plan

Question 3

Crown

Answer 3

Indirect extracoronal restoration which replaces missing tooth structure and restores anatomy

Question 4

Indications for crown placement

Answer 4

Broken down
Trauma
Tooth wear 
Anatomical defect
Hypoplastic conditions and atypical shape
Alter and correct occlusion 
Part of another restoration 
e.g on abutment teeth for bridges and RPDs

Restore missing fx
Appearance

Question 5

Contraindications for crown placement

Answer 5

Other more conservative options available
Poor OH —> high risk of recurrent caries
Very broken down tooth with caries extending subgingivally - difficult to create good margins
Perio conditions - lack of bone support

Question 6

Crown planning

Answer 6

History and examination
Critical thinking and decision making
Detailed planning of crowns and clinical and lab stages

Question 7

History and examination

Answer 7

Patient factors - expectations, compliance, age
Mouth condition
Tooth and teeth in question

Question 8

Effect of age on crown prep planning

Answer 8

Younger patients have larger pulps - higher risk of pulp necrosis - degree of eruption or cooperation of teeth
Older patients have more brittle teeth

Question 9

Patient factors

Answer 9

Attitude and expectation - limitations understood
Cooperation of patient important
Age no upper or lower limit

Females generally more concerned about appearance
Social history
Habits e.g smoking
Cost - budget

Question 10

Mouth condition

Answer 10

Oral hygiene
Status of other teeth
Soft tissue conditions such as mucosal reactions to dental materials

Question 11

Individual tooth factors

Answer 11

Value of tooth
Position 
Appearance 
Pulp status - vital or necrotic?
Periodontium - healthy gingivae 
Occlusion - is it functional 
Root length - bone support

Question 12

Aesthetics - 6 points

Answer 12

Colour
Contour - bulbosity 
Outline - shape 
Symmetry - compare R to L 
Proportion - height:width of central incisors, width all the way (golden ratio) - define ideal aesthetics 
Soft tissue harmony - gum levels

Question 13

Pulp status

Answer 13

Check vitality before crown prep - easier to do RCT pre-crown
15-20% of vital teeth die post crown prep
Take pre-op rad for bone levels and periapical status
Assess size and depth of current restorations

Question 14

Occlusion

Answer 14

Anterior teeth determine the movement of the posterior teeth
Failure to conform to, or create correct anterior guidance will upset posterior occlusion
Understanding and planning the occlusion is essential for success

Question 15

Periodontal factors

Answer 15

Correct and control inflammatory defects
Assess soft tissue contours

Correct if necessary

• Orthodontic correction
• Surgical correction

Question 16

Periodontal factors - issues which could arise

Answer 16

Gingival cleft - perioplastics 
High frenum insertion 
Blunted papilla - can be corrected with fillers
Gingival asymmetry 
Gingival recession - graft

Question 17

Critical questions

Answer 17

Is tooth worth being kept?
Would another option be more suitable?
Is remaining tooth sufficient for a crown preparation
Will direct restoration be needed first?
Is pre-crown tx needed

Question 18

Detailed planning?

Answer 18

Confirmative vs re-organisation 
Crown lengthening? 
Diagnostic wax-up can help visualise result prior to tooth prep
Provisional restorations 
Determination of best material

Question 19

Type of crown

Answer 19

Full coverage
Partial 3/4
Post-core crown

Question 20

Type of crown material

Answer 20

Gold/metal
Metal ceramic or porcelain fused to metal PFM
Dentine Bonded Crown 
High strength core all ceramic crown 
Composite crown

Question 21

Bridge

Answer 21

Tooth borne indirect fixed prosthesis used for replacement of one or more missing teeth

Question 22

Indications for bridge

Answer 22

Missing
Caries, perio disease, trauma, hypodontia, toothwear, oral cancer
iatrogenic

Question 23

Types of bridge

Answer 23

Fixed - fixed on both sides
Fixed moveable
Cantilever
Resin-bonded - pontic with a small wing glued to adjacent tooth
becomes cantilever
becomes fixed fixed resin bonded bridge if two wings present
Implant retained

Question 24

Possible treatment option for partially edentulous patients

Answer 24

No prosthetic treatment

• compromising fx and aesthetics
• over eruption of opposing teeth
• risk of drifting

RPD

• conservative and removable
• periodontal management becomes more difficult - PRF

Conventional tooth supported FPD

• Place crown with replacement prosthetic tooth
• predictable
• invasive, irreversible
• risk of pulp damage
• enamel loss

Resin-bonded bridge

• fixed option
• risk of debond and some aesthetic issues
• 5-10 years lifetime
• risk of metal shadow

Implant-supported FPD

• expensive
• dependent on bone levels

Question 25

Clinical examination

Answer 25

Assess abutment teeth

• perio
• periapical
• root configuration - conical ( more suitable for short span)

Crown-root ratio
Radiographic assessment necessary to evaluate parameters

Question 26

Clinical exam parameters

Answer 26

Length of span - how many teeth missing

Occlusion - assess occlusion but also occlusion of pontic with opposing arch
- sufficient space?

Shape of ridge - affects shape of pontic
- surgical ridge augmentation

Question 27

Predicting final appearance

Answer 27

Study models and diagnostic wax ups

IO trials

• temp RPD
• reshape abutment teeth with composite and temporary attachment of pontic teeth
• make provisional bridges more permanent looking
• -> predict outcome
• -> further mods
• -> time for soft tissues to heal and reshape