Caries removal and definitive restoration practical

Question 1

what are the principles of caries removal and cavity prep

Answer 1

• identify and remove the carious enamel
• remove enamel to identify the maximal extent of the lesion at the amelodentinal junction
• smooth the enamel margins
• remove peripheral caries in dentine from adj then circumferentially deeper
• remove deep caries over the pulp
• outline form modification for enamel finishing
• modify the internal design to match the requirements of the restorative material

Question 2

how to manage caries

Answer 2

• remove enamel caries first
• followed by dentine caries from the adj to the pulp
• access the enamel caries and identify the spread at the adj

Question 3

what can happen if you fail to consider the cavity configuration

Answer 3

dentine bond failure
unsupported enamel fracture
interstitial enamel fracture
post operative sensitivity

Question 4

why is it important to avoid bonding axial surfaces together

Answer 4

there is stress across the width of the cavity if you do this

Question 5

beginning of cavity prep

Answer 5

high speed fissure bur in the central pit
keep bur on the long axis of the tooth and extend into the fissure pattern until there is clean enamel

Question 6

where should the bur be at all times

Answer 6

along the long axis of the tooth

Question 7

how to remove unsupported enamel

Answer 7

red bar ultra fine burr running along the axial enamel wall, or yellow band

Question 8

explain what differential etching is

Answer 8

this is when the first 10 seconds is enamel only etch and then move the etch onto the dentine surface for a further 10
enamel etched for a total of 20s and dentine for 10s

Question 9

how long do you wash the cavity after etching

Answer 9

for as long as it was etched

Question 10

how many mm of composite in one increment

Answer 10

no more than 2mm

Question 11

describe increment 1

Answer 11

occlusal floor of the cavity only, to minimise the polymerisation contraction stress by avoiding bonding enamel or dentine axial walls together

Question 12

why should composite be room temp

Answer 12

so there is good adaptation

Question 13

the internal anatomy of the cavity may have sharp internal anatomical features. how do you smooth these

Answer 13

using a large slow speed round but

Question 14

how should cut dentine be conditioned

Answer 14

using polyacrylic, polymaleic or citric acids.