The failure of directly-placed restorations Flashcards
Why do we restore teeth?
- To stop progression and prevent its recurrence
- Restore occlusion and function
- Restore aesthetics
- Maintain the physiological integrity of the teeth with the adjacent hard and soft tissues
- Restore patient cohort and satisfaction
What is the median survival rate for amalgam?
15-22.5 years
What is the annual failure rate for amalgam?
3%
Why might amalgam fail?
- Incorrect case selection
- Cavity preparation has inadequate retention
- Poor matrix preparation
- Contamination
- Failure to condense
- Improper finishing and polishing procedures
- Micro-leakage, ditching and creep
- Tarnish and corrosion
- Faulty contacts
- Not manipulating amalgam properly
What is failure rate of composite resin materials after 10 years?
50% failure
What is the medical survival of composite?
8 years
What is the annual failure rate for composite?
2%
Why might composite fail?
- Incorrect case selection
2, Difficulty to obtain long term adhesion between the composite resin and the dentine - Failure to light cure composite in increments
- Contamination of the material (moisture control)
- Polymerisation shrinkage causing caries, sensitivity, marginal deficiency
What is the median survival of glass ionomer?
30-42 MONTHS in permeant teeth
What is the annual failure rate for glasswork ionomer?
7%
Why might glass ionomers fail?
- Case selection
- Poor handling of the material at the time of placement
- Excessive occlusal loads
Name the broad factors that affect the success and failure of restorations
- Patient factors
- Operatve factors
- Material factors
What patient factors can lead to restorative failure
- Caries risk
- Heavy occlusal forces (bruxism)
- Tooth to be restored
- Cavity size and location
- Pulpal health
- Periodontal health
- Allergies
What allergy can a patient have that may effect the success of a restoration?
- An oral lichenoid reaction can occur of the oral mucosa against amalgam or gold alloys
- Allergy to HEMA in resin composites/ fissure sealants
What operative factors can lead to restorative failure
- Incorrect choice of restorative dental materials for the situation
- Incorrect cavity design
- If you don’t handle the material in the most effective way
- The use of exemplary clinical techniques in placement & finishing
How can cavity design decease the effectiveness of a restoration?
- No retention factors
- If you don’t remove unsupported enamel
- Weakened cusps
How can a restoration failure affect the patient and dentist?
- Requires time
- Requires money
3, Uses materials - Affects remaining tooth structure
What material factors can lead to restorative failure
- Compressive strength
- Adhesion property
- Resistance to fatigue
- Solubility
- Ditching and creeping
What are ditching and creeping a result of?
A result of the slow deformation of amalgam placed under constant loads
When can ditching and creeping mostly be seen?
When using amalgam with the gamma 2 phase products
What is ditching and creeping?
Breakage of a thin edge creating an irregular V shaped crevice
When does creep happen?
When the corrosive products leak and fill the hap between the tooth and the restoration
Which filling material would you recommend to a patent with a high caries risk?
Amalgam
Give some diseases that can cause restorations to fail
- Caries
- Tooth wear
- Periodontal disease
- Pulpal problems
- Trauma
What technical failures can arise which may cause the restoration to fail?
- Fractured restoration
- Marginal breakdown
- Tooth fracture
- Defective contours
- Failure of retention
How do you detect restoration failure?
- Patent symptoms
- Visual and tactile inspection
- Transillumination
- Radiographic examination
- Occlusal examination
What complaints might a patient come in with if their restoration fails?
- Pain
- Aesthetic concerns
- Discolouration
- Fracture
What is the treatment for oral lichenoid to amalgam?
Replace the amalgam restoration with an amalgam and check if the allergy has vanished
How do we confirm a patient has had a lichenoid reaction to amalgam?
Replace the amalgam restoration with an amalgam and check if the reaction has vanished
How can we visually check if a patent has a failed reaction?
1, Caries 2. marginal breakdown 3 .lost restoration 4. fractured restoration 5. excessive discoloration 6. open contacts and overhangs
What is the main reason a restoration (of any material) is replaced?
Secondary caries
What is primary caries?
Caries formed at a new site on the tooth
What is secondary caries?
Caries found at the margin or under a restoration
What is another name for secondary caries?
Recurrent caries
In which material is risk of secondary caries higher and by how much?
Risk of secondary caries was found to be 3.5x greater for composite than amalgam restorations
Diagnosis of caries should be supported by what?
Radiographic finding and clinical symptoms
Diagnosis of caries should be supported by what?
Radiographic finding and clinical symptoms
How can the tooth next to the restored develop caries?
Due to iatrogenic damage during preparation
This happens in 60-70% of proximal preparations
What can cause a change in colour of a restoration?
Dure to:
- Loss of marginal integrity
- Microleakage of composite resin restorations
- Marginal staining
- Loss of surface lustre and polish
When do repair a restoration?
- When theres no obvious spreading or gross caries that would structurally undermine the restoration or remaining tooth structure
- . If theres sufficient volume of retained restorations remaining and it is strong enough to resist masticatory forces
- If the new restoration can bond to the old one
- When there no potential aesthetic mismatch between old and new materials
