Planning for crowns and bridges

Question 1

Treatment planning

Answer 1

 A plan should be discussed in detail
 Good communication is essential
 Informs pt about:
-current conditions
-extend of dental treatment proposed
-time and cost
-level of home care
-level of maintenance/ repairs/ replacements
 Patient should be informed of possible alterations
before any irreversible procedures are undertaken
 Informed consent is essential

Question 2

Identification of patient needs

Answer 2

 Correction of existing disease
 Prevention of future disease
 Restoration of function
 Improvement of appearance
 Treatme`nt plan should conform to the patient’s
needs not the patient to the “ideal” treatment
plan

Question 3

Available materials and techniques

Answer 3

 Plastic materials
-amalgam
-composite
 Cast metal
 Porcelain
 Metal ceramic
 Veneered composite
 Fiber reinforced composite
 CAD/CAM

Question 4

Restorative options

Answer 4

 Fixed Dental Prostheses
-single crown units
-bridges
 Implant supported prostheses
 Partial Removable Dental Prostheses
 Complete Dentures

Question 5

Crown definition

Answer 5

An indirect extracoronal restoration
which replaces missing tooth structure and
restores anatomy

Question 6

Indications for crowns

Answer 6

 Badly broken down or previously heavily
restored teeth
 Trauma
 Tooth wear
 Hypoplastic conditions and Atypical shape
 To alter occlusion
 Part of another restoration
 Restore missing function
 Mechanical problems
 Appearance

Question 7

Contraindications for crowns

Answer 7

 Other more conservative restorative options are
viable
 Poor OH
 Very broken-down tooth with caries extending
subgingivally
 Periodontal condition- not enough bone
support

Question 8

Planning for crowns

Answer 8

 History and examination
 Critical thinking and decision making
 Detailed planning of the crown(s) and
performing clinical and laboratory stages

Question 9

Planning for crowns: history and examination

Answer 9

 Patient factors
 Mouth condition
 Tooth/teeth in question

Question 10

Planning for crowns: history and examination

-patient factors

Answer 10

 Attitude and expectation; understands limitations of
procedure
 Cooperation of the patient is important; crown is a
complex procedure, requires few appointments
 Age: no upper or lower age limit but…older patient
usually have more brittle teeth, younger patient large
pulp chambers!
 With young patients you need to consider:
-size of pulp
-degree of eruption of tooth
-cooperation of patient
 Female patients are generally more concerned
about the appearance
 Social history, profession i.e. musicians,
 Habits i.e. pipe smoking, availability
 Cost

Question 11

Planning for crowns: history and examination

-mouth condition

Answer 11

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

Question 12

Planning for crowns: history and examination

-individual tooth factors

Answer 12

 Value of the tooth
 Position of the tooth in the mouth
 Appearance
 Pulp status
 Periodontium
 Occlusion
 Root length-bone support

Question 13

Aesthetics - the 6 basic points

Answer 13

 Colour
 Contour
 Outline
 Symmetry
 Proportion
 Soft tissue
harmony

Question 14

Pulp status for crowns

Answer 14

 Always check vitality prior to crown
preparation (EPT, ethyl chloride)
 15-20% of vital teeth will become non-vital
following crown preparation
 Always take a preoperative periapical
radiograph
 Assess size and depth of current restorations
 Remember – its easier to undertake endodontic
treatment prior to placing the crown

Question 15

Occlusion for crowns

Answer 15

 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 16

Periodontal factors for crowns

Answer 16

 Correct and control inflammatory defects
 Assess soft tissue contours
 Correct if necessary
-orthodontic correction
-surgical correction

Question 17

Examples of periodontal factors for crowns

Answer 17

Gingival cleft
High frenum insertion
Blunted papilla
Gingival asymmetry
Ridge defect
Gingival recession

Question 18

Planning for crowns - critical thinking and decision making

Answer 18

 Is the tooth worth to be kept? Or better to be
extracted?
 If it is suitable to be kept could another restorative
option be more suitable?
 If it is suitable for crowning is the remaining tooth
sufficient for a crown preparation?
 If not will it need restoration with a direct material first?
 And if yes which one? Amalgam, Composite or GIC??
 Is pre-crown treatment necessary? Orthodontic
treatment, bleaching, RCT…

Question 19

Planning for crowns - Detailed planning of the crown(s) and

performing clinical and laboratory stages

Answer 19

 Conformative versus re-organisation approach
 Need for crown-lengthening?
 Diagnostic wax-up can help visualise result prior
to tooth preparation
 Provisional restorations
 Determination of best material

Question 20

Conformative approach

Answer 20

provision of restorations ‘in harmony with the existing jaw relationships’

Question 21

Reorganisation approach

Answer 21

The
objective of the ‘re-organized approach’
is to provide an occlusion that is more
ideal

Question 22

Need for crown lengthening surgery?

Answer 22

Dental surgeons perform crown lengthening by recontouring gum tissue, and sometimes bone, to expose more of a tooth’s surface for a crown

Question 23

Type of crown

Answer 23

 Full coverage crown
 Partial coverage crown: ¾ crown
 Post-core crown

Question 24

Type of crown regarding the material of fabrication

Answer 24

 Gold or metal
 Metal ceramic or Porcelain Fused to Metal
(PFM)
 Dentine Bonded Crown (Ceramic)
 High strength core all ceramic crown
 Composite crown

Question 25

Definition of a bridge

Answer 25

Bridge is a tooth-borne indirect fixed prosthesis which is used for the replacement of one or more missing teeth

Question 26

Indications for a bridge

Answer 26

 Replacement of missing teeth and restoration of
edentulous areas
 Reasons for tooth loss:
-caries
-periodontal disease
-trauma
-hypodontia
-toothwear
-oral cancer
-iatrogenic

Question 27

Types of bridges

Answer 27

 Fixed-fixed
 Fixed-moveable
 Cantilever
 Resin bonded
 Implant retained

Question 28

Planning for bridges

Answer 28

(Similar to crown planning)
 History and examination
 Critical thinking and decision making
 Detailed planning of the bridge(s) and
performing clinical and laboratory stages
 Is the patient suitable for a bridge?
*try to simplify the treatment*

Question 29

Possible treatment option for partially

edentulous patients

Answer 29

 No prosthetic treatment: compromised function
and aesthetics. Risk of tilting the adjacent teeth and
over eruption of the opposing teeth.
 RPD: Conservative but removable option
 Conventional tooth supported FPD: Invasive and
irreversible approach, loss of enamel, pulp damage
but fixed and predictable solution
 Resin-bonded bridge: Conservative fixed option
but risk of debond and some aesthetic issues
 Implant-supported FPD: Bone quantity and costs

Question 30

Clinical examination for bridges

Answer 30

 Assessing abutment teeth
-periodontal assessment
-periapical assessment
-root configuration; teeth with conical roots more
suitable for short-span bridge
 Crown-root ratio: optimum ration 2:3, a ratio 1:1
is the minimum accepted
 Radiographic assessment is necessary to
evaluate the above parameters
 Length of span; how many teeth are missing? Is a
fixed-fixed bridge more suitable than a cantilever
bridge? Implant-supported bridge?
 Occlusion: the occlusion of abutment tooth/teeth
should be assessed but also the occlusion of pontic
with the opposing arch should be predicted
 Shape of ridge: this will affect the shape of the pontic,
if it is critical should be taken into consideration and
preparatory treatment should be done before
preparing the bridge i.e. surgical ridge augmentation
or other treatment plan i.e. PD

Question 31

Predicting the final appearance

Answer 31

 Use of study models and diagnostic wax-ups
 Intra-oral trials with the use of:
-temporary RPD
-reshaping of abutment teeth with composite and
temporary attachment of pontic teeth
provisional lab-made bridges- more “permanent”
than temporary bridges:
–>used to predict outcome,
–>allow further modifications for aesthetic reasons
–>allow modifications to the occlusion
–>give time to soft tissues to heal and reshape before final restoration