indirect restorations- inlays on onlays

Question 1

when do we have an increased risk of fracture

Answer 1

if the height to ratio base is greater than 1 the tooth is greater risk of fracture

Question 2

what is the greater risk of loss in a crowned tooth vs uncrowned

Answer 2

6 times greater chance

Question 3

which tooth position is optimum canine guidance or group funciton

Answer 3

canine guidance as the pt chews there is less pressure and force

Question 4

why is group function not as ideal

Answer 4

as the posterior teeth are in occlusion and this will put more stress on the cusps

Question 5

what are some risks of fractured tooth

Answer 5

crowned vs uncrowned
tooth treated
grinding/clenching jaw
height:base ratio

Question 6

what are some management options to reduce the risk of fracture

Answer 6

bonding

cusp coverage

Question 7

what is the issues with bonding

Answer 7

polymerisation shrinkage

Question 8

how do we try tor educe polymerisation shrinkage

Answer 8

minimise this y looking at the configuration factor

Question 9

what is the configuration factors

Answer 9

involves the number of bonded surfaces/ number of unbonded surfaces

Question 10

when doing a class 2 restoration what do we need to consider

Answer 10

that we need to achieve a good contact point and this will minimise food packing

Question 11

when is the indication for an inlay

Answer 11

used to achieve a good contact point if it is too wide

Question 12

define inlay

Answer 12

an indirect restoration that is intracoronal constructed in the lab and cemented into a tooth

Question 13

what are the advantages with inlays

Answer 13

made outside the lab
polymerisation shrinkage occurs outside the mouth
bonded in place

Question 14

disadvantages with inlays

Answer 14

no cusp coverage
small MO/DO cavities in molar/premolars
conservative MOD in molar

Question 15

what do we need to try to do an inlay

Answer 15

canine guidance
low caries risk
about 1/3th buccal to lingual width
height:width less than 1.1

Question 16

how much percentage of tooth tissue loss is there in a full coverage crown

Answer 16

67-75%

Question 17

definition of a cuspal coverage

Answer 17

an indirect restoration constructed in the lab and cemented in the tooth which may contain a intracoronal aspect BUT COVERS 1/MORE CUSPS

Question 18

advantages of cuspal coverage

Answer 18

→ Uses the intracoronal element to provide retention and cuspal protection
→ Doesn’t extend outside the tooth
higher margins less likely to cause irritation

Question 19

indications for cuspal coverage

Answer 19

Teeth with larger restoration but sound B and L walls needing cuspal protection eg
→ RCT teeth 
→ Wider MODs
→ MODs in premolars 
→ Low caries rate in pt 
→ Over 1/2 B-L width 
→ Height: width <1.1 
→ Parafunction 
→ XS cusp wear 
Group function

Question 20

what is the longevity of gold inlay/onlay

Answer 20

approx 10 years- 96%

Question 21

what is the longevity of ceramic inlays

Answer 21

8 years 80%

Question 22

what is the longevity for ceramic onlays

Answer 22

8 years

Question 23

what might be the issues with CAD/CAM inlays

Answer 23

might be more successful but issues with submargination and hypersensitivity if not ideal shape

Question 24

how do we choose what material it should be made from

Answer 24

structure
retention and resistance
aesthetics
tooth tissue preservation