the failure of directly placed restorations Flashcards
why do we restore teeth
to stop lesion progression and prevent its recurrences
restore occlusion and function
restore aesthetics
maintain physical integrity
restore comfort and satisfaction of the patient
what is the median survival rate of amalgam
15 years in one study upto 22.5 years in another
what is the annual failure rate of amalgam
3%
what are some causes of amalgam failure
Incorrect case selection Cavity preparation: inadequate retention Poor matrix preparation Amalgam manipulation Contamination Failure to condense Improper finishing and polishing procedures Post-operative pain : inappropriate lining material Microleakage, ditching and creep Tarnish and corrosion Faulty contacts
what is the median survival of composite
8 years
what is the annual failure rate of composite
2%
what are the causes of composite failure
Incorrect case selection
The difficulty to obtain long term adhesion between the composite resin and the dentine, failure at the gingival margin is not uncommon
Failure to light cure composite in increments
Contamination of the material: moisture control
Polymerization shrinkage causing caries, fracture, sensitivity, marginal deficiency
what is the survival of glass ionomer in permanent teeth
30-43 months
what is the annual failure rate of GIC
7%
what are the implication of restorative failure
time cost material choice technique remaining tooth structure
why might gic fail
DUE to case selection
what might affect the success or failure of restorations
Patient factors
Operative factors
Material factors
what are patient factor of why restorations might fail
Caries risk: Oral hygiene, diet regular dental check up Heavy occlusal forces: bruxism Tooth to be restored Cavity size and location Pulpal health Periodontal health Allergies
what happens when patients are allergic to amalgam or gold alloys
oral lichenoid reaction of the oral mucosa
what are operative factors of why restorations might fail
The correct choice of restorative dental material for the situation
Cavity design ,retention, removal of unsupported enamel and weakened cusps
The optimal handling of that material
The use of exemplary clinical techniques in placement & finishing
why might restorations fail due to materials
compressive strength
regdity
surface hardness
flexural strength
what is ditching and creep
slow deformation of amalgam placed under constant load, When the load is less than necessary to produce fracture ,causing marginal breakdown. Mostly seen when using amalgam with gamma 2 phase products.
what shape does ditching or crevicing make
irregular V shape crevice
when does creep happen
the corrosive products leak and fill the gap between the tooth and the restoration
which diseases cause restorations to fail
Caries Tooth wear Periodontal disease Pulpal problems Trauma
how do you detect a failed restoration clinically
patient symptoms: pain aesthetic concerns discolouration and fracture
visual + tactile: caries marginal breakdown
transillumination
radiographic examination
occlusal exam
what do we consider in the radiographic examination
caries apical and perio status and overhangs
what is the risk of secondary caries in composite
3.5 x
what are the causes of colour changes
loss of marginal integregity microleakage
marginal staining
loss of surface lustre and polish
when do we repair the restoration
No obvious spreading of gross caries that would structurally undermine the restoration or remaining tooth structure
Sufficient volume of retained restoration remaining and it is strong enough to resist masticatory forces
The possibility to bond or mechanically interlock the new restoration into the ‘old’ restoration and tooth
No potential aesthetic mismatches between the ‘new’ and ‘old’ materials
what materials might produce an oral lichenoid reaction
amalgam or gold alloys or sensitivity to HEMA in resin
why does amalgam have reduced microleakage
due to the formation of corrosive products
which ways would restorations fail
disease or technical failure
give examples of technical failure
Fractured restoration Marginal breakdown Tooth fracture Defective contours Failure of retention
where does secondary or recurrent caries occur
at the margin or underneath a restoration
