Operative Dent

Question 1

What 4 things are there a strong relationship between in cavity preparation?

Answer 1

• the position of the caries
• the extent of the caries
• the shape of the prepared cavity
• the final restorative material

Question 2

Name 4 positions of caries?

Answer 2

= pit & fissure
= approximal
= smooth surface
= root

Question 3

What are the 6 principles of cavity design and preparation?

Answer 3

= identify and remove carious enamel
= remove enamel to identify the maximal extent of the lesion at the amelodentinal junction and smooth the enamel margins
= progressively remove peripheral caries in dentine - from the ADJ first, then circumferentially deeper
= only then remove deep caries over pulp
= outline form modification (cava-surface margins)- enamel finishing, occlusion, requirement of the restorative material
= internal design modification - internal line and point angles, requirement of the restorative material

Question 4

What 5 things are critical in the final seal of the restoration (cavity prep)?

Answer 4

= smooth margins
= appropriate CSMA
= no unsupported tooth tissue
= no stress connectors
= internal anatomy that allows adaptation of material

Question 5

Advantages of composite?

Answer 5

= aesthetics
=conservation of tooth tissue
= support for remaining tooth tissue
=adhesion/bonding
=command cure
= low thermal conductivity
= elimination of galvanism
= amalgam alternative - NHS SDR

Question 6

Negatives of using amalgam…

Answer 6

= does not bond to enamel or dentine
= does not support the tooth
= common for pieces of tooth to breakaway

Question 7

Minimum depth of amalgam bulk?

Answer 7

= 2mm deep

Question 8

What are some examples of retention?

Answer 8

= undercuts
= dovetail
=key
= isthmus

Question 9

What can any micro-leakage lead to?

Answer 9

penetration and ingress of bacteria, collection of plaque and secondary caries

Question 10

Can you leave caries at the margins of the cavity?

Answer 10

NO

Question 11

How is the hybrid layer made?

Answer 11

= removal of smear layer
= solubilised surface
= collagen fibril matrix
= no water content
= solvent/aqeuous primer
= hydrophobic resin
= air inhibition

Question 12

What does configuration factors mean?

Answer 12

ratio of bonded surfaces to un-bonded surfaces ( important for composite restorations)

Question 13

What is used to etch the enamel?

Answer 13

37% phosphoric acid - to roughen the surface

Question 14

Why else are we etching the enamel and dentine?

Answer 14

to remove the smear layer

Question 15

Smear layer?

Answer 15

layer of organic material which is produced whenever we use a high speed hand piece or slow speed hand piece on dentine (we want to expose out dentinal tubules)

Question 16

Why should you not dry out dentine?

Answer 16

post-operative sensitivity

Question 17

What composite has less filler content?

Answer 17

flowable composite (reducing the polymerisation contraction stresses)

Question 18

Why do we not join one enamel margin to another enamel margin?

Answer 18

• gives us the risk of cohesive enamel fracture

Question 19

How can you counter contraction stresses?

Answer 19

incremental build up
warm composite
flowable composite
curing regime
C-factor considerations