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