The failure of directly-placed restorations

Question 1

Why do we restore teeth?

Answer 1

1. To stop progression and prevent its recurrence
2. Restore occlusion and function
3. Restore aesthetics
4. Maintain the physiological integrity of the teeth with the adjacent hard and soft tissues
5. Restore patient cohort and satisfaction

Question 2

What is the median survival rate for amalgam?

Answer 2

15-22.5 years

Question 3

What is the annual failure rate for amalgam?

Answer 3

3%

Question 4

Why might amalgam fail?

Answer 4

1. Incorrect case selection
2. Cavity preparation has inadequate retention
3. Poor matrix preparation
4. Contamination
5. Failure to condense
6. Improper finishing and polishing procedures
7. Micro-leakage, ditching and creep
8. Tarnish and corrosion
9. Faulty contacts
10. Not manipulating amalgam properly

Question 5

What is failure rate of composite resin materials after 10 years?

Answer 5

50% failure

Question 6

What is the medical survival of composite?

Answer 6

8 years

Question 7

What is the annual failure rate for composite?

Answer 7

2%

Question 8

Why might composite fail?

Answer 8

1. Incorrect case selection
   2, Difficulty to obtain long term adhesion between the composite resin and the dentine
2. Failure to light cure composite in increments
3. Contamination of the material (moisture control)
4. Polymerisation shrinkage causing caries, sensitivity, marginal deficiency

Question 9

What is the median survival of glass ionomer?

Answer 9

30-42 MONTHS in permeant teeth

Question 10

What is the annual failure rate for glasswork ionomer?

Answer 10

7%

Question 11

Why might glass ionomers fail?

Answer 11

1. Case selection
2. Poor handling of the material at the time of placement
3. Excessive occlusal loads

Question 12

Name the broad factors that affect the success and failure of restorations

Answer 12

1. Patient factors
2. Operatve factors
3. Material factors

Question 13

What patient factors can lead to restorative failure

Answer 13

1. Caries risk
2. Heavy occlusal forces (bruxism)
3. Tooth to be restored
4. Cavity size and location
5. Pulpal health
6. Periodontal health
7. Allergies

Question 14

What allergy can a patient have that may effect the success of a restoration?

Answer 14

1. An oral lichenoid reaction can occur of the oral mucosa against amalgam or gold alloys
2. Allergy to HEMA in resin composites/ fissure sealants

Question 15

What operative factors can lead to restorative failure

Answer 15

1. Incorrect choice of restorative dental materials for the situation
2. Incorrect cavity design
3. If you don’t handle the material in the most effective way
4. The use of exemplary clinical techniques in placement & finishing

Question 16

How can cavity design decease the effectiveness of a restoration?

Answer 16

1. No retention factors
2. If you don’t remove unsupported enamel
3. Weakened cusps

Question 17

How can a restoration failure affect the patient and dentist?

Answer 17

1. Requires time
2. Requires money
   3, Uses materials
3. Affects remaining tooth structure

Question 18

What material factors can lead to restorative failure

Answer 18

1. Compressive strength
2. Adhesion property
3. Resistance to fatigue
4. Solubility
5. Ditching and creeping

Question 19

What are ditching and creeping a result of?

Answer 19

A result of the slow deformation of amalgam placed under constant loads

Question 20

When can ditching and creeping mostly be seen?

Answer 20

When using amalgam with the gamma 2 phase products

Question 21

What is ditching and creeping?

Answer 21

Breakage of a thin edge creating an irregular V shaped crevice

Question 22

When does creep happen?

Answer 22

When the corrosive products leak and fill the hap between the tooth and the restoration

Question 23

Which filling material would you recommend to a patent with a high caries risk?

Answer 23

Amalgam

Question 24

Give some diseases that can cause restorations to fail

Answer 24

1. Caries
2. Tooth wear
3. Periodontal disease
4. Pulpal problems
5. Trauma

Question 25

What technical failures can arise which may cause the restoration to fail?

Answer 25

1. Fractured restoration 2. Marginal breakdown 3. Tooth fracture 4. Defective contours 5. Failure of retention

Question 26

How do you detect restoration failure?

Answer 26

1. Patent symptoms 2. Visual and tactile inspection 3. Transillumination 4. Radiographic examination 5. Occlusal examination

Question 27

What complaints might a patient come in with if their restoration fails?

Answer 27

1. Pain 2. Aesthetic concerns 3. Discolouration 4. Fracture

Question 28

What is the treatment for oral lichenoid to amalgam?

Answer 28

Replace the amalgam restoration with an amalgam and check if the allergy has vanished

Question 29

How do we confirm a patient has had a lichenoid reaction to amalgam?

Answer 29

Replace the amalgam restoration with an amalgam and check if the reaction has vanished

Question 30

How can we visually check if a patent has a failed reaction?

Answer 30

``` 1, Caries 2. marginal breakdown 3 .lost restoration 4. fractured restoration 5. excessive discoloration 6. open contacts and overhangs ```

Question 31

What is the main reason a restoration (of any material) is replaced?

Answer 31

Secondary caries

Question 32

What is primary caries?

Answer 32

Caries formed at a new site on the tooth

Question 33

What is secondary caries?

Answer 33

Caries found at the margin or under a restoration

Question 34

What is another name for secondary caries?

Answer 34

Recurrent caries

Question 35

In which material is risk of secondary caries higher and by how much?

Answer 35

Risk of secondary caries was found to be 3.5x greater for composite than amalgam restorations

Question 36

Diagnosis of caries should be supported by what?

Answer 36

Radiographic finding and clinical symptoms

Question 37

Diagnosis of caries should be supported by what?

Answer 37

Radiographic finding and clinical symptoms

Question 38

How can the tooth next to the restored develop caries?

Answer 38

Due to iatrogenic damage during preparation | This happens in 60-70% of proximal preparations

Question 39

What can cause a change in colour of a restoration?

Answer 39

Dure to: 1. Loss of marginal integrity 2. Microleakage of composite resin restorations 3. Marginal staining 4. Loss of surface lustre and polish

Question 40

When do repair a restoration?

Answer 40

1. When theres no obvious spreading or gross caries that would structurally undermine the restoration or remaining tooth structure 2. . If theres sufficient volume of retained restorations remaining and it is strong enough to resist masticatory forces 3. If the new restoration can bond to the old one 4. When there no potential aesthetic mismatch between old and new materials