ICP-23 Failure of Restorations

Question 1

How long do amalgam fillings last

Answer 1

At 10 years <10% of restorations replaced

Question 2

What effect does operator skill, size of restoration and type of alloy have on how long amalgam fillings last

Answer 2

• Operator skill = no effect
• Size of restoration = no effect
• Dispersed phase high Cu alloys tend to last longer

Question 3

How long do composite with dentin bonding fillings last

Answer 3

Failure in cervical cavities typically begins <1yr

Question 4

What about composite with dentine bonding can improve its survival

Answer 4

• Improved survival with acidic primer
• Enamel etching and mechanical retention improves retention
• Dentine bonding reduces post-operative pain

Question 5

What does it mean if a restoration has failed

Answer 5

• Secondary/recurrent disease: invasive caries in dentine, pulpal necrosis
• Loss of function: loss of restoration, loss of surrounding tissue
• “Inevitable” progression to caries
• Microleakage causing sensitivity or pain
• Appearance unacceptable to patient

Question 6

What are the symptoms of secondary invasive caries in dentine

Answer 6

• Usually none
• Discolouration (anterior)
• Symptom of pulpitis

Question 7

What are the signs of secondary invasive caries in dentine at the restoration margin

Answer 7

• Visual (not approximally)
• Radiography (approximatif)
• Tactile

Question 8

What are the signs of secondary invasive caries in dentine in deep tissue

Answer 8

• Visual (sometimes)

- Radiography (sometimes)

Question 9

What are the symptoms of secondary pulpal necrosis

Answer 9

e.g. of pulpitis

Question 10

What are the signs of secondary pulpal necrosis

Answer 10

Loss of vitality on sensibility testing +/- peri-radicular radiographic change

Question 11

What is a symptom/sign of loss of function of a restoration

Answer 11

• Restoration can be loose or lost

- Fractured tooth/cusp causing loss of occluding surface

Question 12

What are the signs of the “inevitable” progress to caries

Answer 12

• Fractured restoration permitting microleakage

- Loss of marginal integrity permitting microleakage

Question 13

What does microleakage of a restoration cause

Answer 13

Microleakage will result in bacterial ingress and caries which causes failure of the restoration

Question 14

How might the appearance of a restoration become unacceptable to a patient

Answer 14

• Marginal staining (anteriors)
• Discolouration of anterior material
• Contrast with “normal” darkening of tooth
• Gingival recession (darker roots)
• Desire for “white fillings”

Question 15

What factors can cause a restoration to fail

Answer 15

• Patient factors
• Operator factors (iatrogenic)
• Materials factors
• Chance e.g. trauma

Question 16

What are some patient factors that can cause a restoration to fail

Answer 16

• Cariogenic Factors: Diet, Plaque, Saliva/xerostemia, Poor oral hygiene
• Para-functional habits
• Appearance unacceptable
  NB - when giving diet and hygiene advice, customise your advice to your patient lifestyle

Question 17

What are some operator factors that can arise from errors in planning that lead to a failed restoration

Answer 17

• Failure to promote prevention
• Failure to check occlusion before management of tooth
• Failure to take account of “whole patient” i.e. management of caries/periodontitis risk
• Inappropriate restoration for tooth or situation
• Inappropriate restorative material

Question 18

What are some operator factors that can arise from errors in execution that lead to a failed restoration

Answer 18

• Damage to pulp-dentine complex
• Leaving infected carious tissue
• Bad cavity design for restorative material
• Failure to reduce height of tall thin cusps in occlusion
• Incorrect use of material
• Failure to give self care instructions
• Using composite resin when the pulpal margin is in dentine

Question 19

What material factors can lead to failure of a restoration

Answer 19

Causes of failure differ between materials:

• Fracture
• Corrosion, dissolution, chemical degradation
• Wear
• Discolouration/staining
• Some materials normally have much greater longevity than others

Question 20

Should you repair or replace a failed restoration

Answer 20

Flawed data suggests:

• Repairs = similar short term survival to replacement
• Repairs are less invasive

Question 21

How to decide repair/replacement with the patient

Answer 21

• Explain treatment options and associated risks
• Discuss current state of evidence base underpinning treatment options
• Combine clinical expertise with patient’s informed choice

Question 22

What are some of the ways that you can improve composite restorations

Answer 22

• Work on a clean tooth surface - clean surface with wet pumice slurry
• Etch only area you’re working on, wash thoroughly
• Check for dry air, line in your three in one
• Enamel should be completely dry, dentine should not be desiccated
• Rub Primer and bonding agents on the surface to improve penetration
• Point the centre of the beam of the light cure on the area being cured
• Use small increments and shape appropriately to minimise cutting back
• Polish
• Don’t paint unfilled resin/bond on your finished restoration