Management of approximal caries

Question 1

Why is approximate caries common?

Answer 1

Contact point of tooth is a nice stagnation point for bacteria

Question 2

At what point does approximal caries need restoration?

Answer 2

When the lesion reaches the ADJ

Question 3

On occlusal surfaces what is the most common restoration? Why is this not the same for approximal?

Answer 3

PRR and FS over the top

Approximal is harder to get to

Question 4

What factors are necessary for a good clinical examination to diagnose approximal caries?

Answer 4

Clean, dry, good lighting

Question 5

What probe is used to test the hardness of the enamel in a suspected lesion?

Answer 5

Briault/straight probe

Question 6

What is transillumination?

When is it useful?

Answer 6

Reflecting operating light through contact point. This is useful for posterior teeth.
The bright light will make the caries appear darker

Question 7

What technique is particularly useful for viewing approximal caries?

Answer 7

Seperators

Question 8

What types of radiographs are useful for diagnosing approximal caries?

Answer 8

Bitewiing, DPTs, periapical

Question 9

How does approximal caries spread?

Answer 9

In a vertical line, simultaneously pulpward

Question 10

Name 5 problems with radiographs for diagnosis.

Answer 10

Cervical burn-out = area of black between and enamel and bone, looking like caries
Contrast (over/under-exposure)
Restorations (lesions may be beneath or hidden by restorations)
Problems if bean angulation is wrong
Superimposition

Question 11

How can you tell the difference between cervical burn-out and caries?

Answer 11

Burn out will be more triangular shape and closer to the bone, it will affect equal number of teeth on the X-ray, not just one.
Caries will be more rounded with no defined border, it will spread into enamel nd subgingivally

Question 12

How long does approximal caries take to reach dentine in permanent teeth?

Answer 12

3-4 years, in a reversible cycle of demineralisation and remineralisation

Question 13

Name and explain 4 ways approximal caries can be prevented?

Answer 13

Eliminate carbohydrate substrate (dietary analysis and advice)
Increase resistance of host (fluoride)
Eliminate bacterial plaque (inter proximal cleaning techniques)
Diet diary (define the problem)

Question 14

Name 4 aims of operative treatment

Answer 14

Remove bacterial infection
Reinforce the remaining tooth structure
Restore function and aesthetics
Protect the pulp from bacterial invasion

Question 15

Name the 3 steps that come before designing a cavity?

Answer 15

Gain access to caries
Remove caries (clear periphery at ADJ)
Put instruments down --> Look, think, design

Question 16

What 5 things must you think about during ‘look, think, design’ of a cavity?

Answer 16

Choice of material
Retention of material
Features to protect the remaining tooth structure
Features to maximise strength of the tooth and restoration
Shape and position of the cavity margins

Question 17

What are the 3 types of materials that can be used for designing a cavity?

Answer 17

Direct e.g. amalgam, composite, glass ionomer
Indirect e.g. inlet/onlay
Combination

Question 18

What 5 factors affect the retention of the material?

Answer 18

Grooves
Undercuts
Dovetails (pins)
Dentine bonding
Physical and chemical bonds

Question 19

What features of a cavity protect the remaining tooth structure?

Answer 19

Removing unsupported enamel
Modify weak cusps
Occlusal coverage
Splinting with adhesive materials

Question 20

What features of a cavity maximise strength of the tooth and restoration?

Answer 20

Adequate thickness of material
Ensure sufficient tooth is left
Tissue has been removed

Question 21

Shape and position of cavity margins

a) amalgam and porcelain
b) composite
c) position in relation to gum
d) contact area between teeth
e) margins on anterior sites

Answer 21

a) 90-degree margin
b) bevelled margin
c) supragingival
d) clear contact area
e) left intact to improve aesthetics

Question 22

Name 3 ways approximal caries can be accessed

Answer 22

Occlusally
Buccal/lingually
Directly

Question 23

How is approximal caries accessed occlusally?

Answer 23

Through the marginal ridge - always try to preserve after but if too little is left it will just break so remove

Question 24

When can approximal caries be accessed directly?

Answer 24

When there is adjacent tooth loss

Question 25

Why try to preserve marginal ridge?

Answer 25

Removing reduces strength of tooth by 69%

Question 26

What are the limitations of dental amalgam?

Answer 26

Not used in children under 15/pregnant/breastfeeding

Destructive preparations

Question 27

Differences and similarities between posterior amalgam vs composite preparations

Answer 27

Composite -> access caries sousing larger, slower speed burr
Both - remove caries at ADJ
Amalgam –> at this point consider retention factors e.g. make groove
Composite –> remove surface contaminants , etch, bond and restore
Amalgam –> insert metal matrix band and insert amalgam