CSA failure of restorations Flashcards
Why do we restore teeth?
- improve aesthetic shape/shade/angulation
- function
- Stop lesion progression and prevent its recurrence
- Restore occlusions/ health of periodontium
- Restore patient comfort and satisfaction
what depends on how long do restorations last?
o Success – Restoration should fulfil objective
o Survival rate – How long does restorations last
o Longevity – How long does restoration last?
o Failure – Inability to meet desired outcome
What is median survival rate for amalgam
15 years
What is amalgam recommended for ?
posterior teeth with heavy occlusal forces and patient with high caries risk
What is failure rate of composite?
50% AFTER 10 YEARS
MEDIAN survival is 8 years
what is median survival of GIC?
30-42 months in permanent teeth
What can’t GIC withstand easily?
occlusal forces
when does amalgam have a smaller survival rate?
for smaller cavities
what are the implications of restorative failure?
time/cost/material choice/technique/remaining tooth structure
What factors affect restoration longevity?
o Patient factors
o Operative factors
o Material factors
What are patient risk factors?
- Caries risk:
- Heavy occlusal forces:
- Tooth to be restored
- Cavity size and location
- Pulpal health
- Periodontal problems
- Allergies
What sort of heavy occlusal forces are there?
bruxism, risk of fracture under heavy load
what does a failed restoration on anterior teeth mean?
patient will seek treatment earlier
What does location of cavity mean?
cavity near gingival margin affected by moisture control
What sort of allergies are there?
- Oral lichenoid reaction
* Allery to amalgam or gold alloys, or sensitivity to HEMA in resin composites/fissure sealant
What are the allergies usually like?
painless and benign
What are operative factors to consider?
- know qualities and properties of material
- Correct cavity design
- Optimal handling of material
- Use of exemplary clinical techniques in placement & finishing
What is correct cavity design for amalgam?
undercuts for amalgam & must be deeper than 2mm
o Retention/ Removal of unsupported enamel and weakened cusps
What are material factors to consider?
- Thermal expansion
- Compressive strength
- Rigidity (modulus of elasticity)
- Surface hardness and surface wear characteristics
- Flexural strength
What does thermal expansion lead to?
micro leakage and fracture
what is compressive strength ?
amount of force material can take before breaks
What are factors linking to micro leakage?
adhesion property , e.g. composite has a good bonding to tooth so less micro
Does amalgam have good adhesive properties?
ability to seal itself around margins, known as creep
What does creep reduce for amalgam?
secondary caries
what can form between restorations and tooth surface over time?
gaps
What is creep ?
pulling away of restoration due to occlusal forces
what is a result of creep?
ditching , food packing can occur here
Way in which restorations fails due to disease?
o Caries o Tooth wear o Periodontal disease o Pulpal problem o Trauma
What can overhanged restorations act as ?
PFS
Way in which restorations fail due to technicalities ?
o fractured restoration
o Marginal breakdown (micro leakage
o Defective contours
o failure of retention
How do you detect a restoration failure?
- Ppt. symptoms:
- Visual and tactile inspection:
- Transillumiation
- Radiographic examination
- Occlusal examination:
What are patient symptoms?
o Pain
o Aesthetic concerns
o Discolouration
o Fracture
What are visual and tactile inspections?
o caries, o Marginal breakdown o Lost restoration o Excessive discoloration o Open contacts and overhangs
What is transillumination ?
light behind teeth and seeing
What is radiographic examination?
caries apical and periodontal status, overhangs present
What is occlusal examinatiion?
occlusal with adjacent teeth, State of tissue, Loss of anatomy of tooth
what is the most common reason for restoration failure?
caries
What is secondary caries?
caries next to a restoration
How does secondary caries form?
o due to incorrect handling/packing/choice of material/dentist didn’t remove all the caries and sealed it up
What is the risk for secondary caries like?
3.5 times greater for composite
what are aesthetic reasons to why restorations fail?
•Causes of colour changes o Loss of marginal integrity o Micro leakage of composite resin restorations o Marginal staining o Loss of surface luster and polish
When do we repair restoration?
o No obvious spreading of gross caries
o Sufficient volume of retained restoration remaining and strong enough to resist masticatory forces
o can bond new restoration into ‘old’ restoration and tooth
o No aesthetic mismatches
When do we replace a restoration ?
if caries is present
