Operative Dentistry

Question 1

what aspects of your cavity preparation should you consider for composite

Answer 1

prism orientation
avoid cavosurface margins

Question 2

what is the result of caries being left at the EDJ

Answer 2

unsupported enamel and early breakdown of restoration margin when microleakage occurs

Question 3

what is assessed with sensibility testing

Answer 3

the neural activity - not vascular supply

Question 4

give an example of a vitality test

Answer 4

pulse oximetry - measures the blood flow

Question 5

what are the four requirements for caries to develop

Answer 5

susceptible tooth surface
Time
Bacteria
Sugar

Question 6

name four potential plaque traps on a tooth

Answer 6

pit and fissures
interproximal
smooth surfaces
root surface

Question 7

what are reasons for treating tooth loss

Answer 7

aesthetics
function
speech
maintenance of teeth

Question 8

what is a bridge

Answer 8

prothesis that replaces a missing tooth or teeth and is attached to one or more natural teeth or implants

Question 9

what are the two types of bridgework

Answer 9

adhesive
conventional

Question 10

what are indications for a bridge

Answer 10

favourable alignment of abutments
favourable occlusion
aesthetics
big teeth

Question 11

what are contra-indications for a bridge

Answer 11

abutment prognosis poor
likely to lose more teeth in same arch
uncooperation
periodontal disease
tilted and rotated teeth
periapical status

Question 12

what are the two designs that conventional or adhesive bridgework can be

Answer 12

cantilever - abutment tooth on one side
fixed-fixed - abutment teeth on both sides

Question 13

what are advantages of cantilever bridges

Answer 13

minimal to no prep
no LA required
less surgery time
less costly

Question 14

what are disadvantages of cantilever bridges

Answer 14

rigorous clinical technique
metal shine through
chipping porcelain
occlusal interference

Question 15

what is required when canines are going to be used as part of the bridge unit

Answer 15

facebow registration

Question 16

what is a direct bridge

Answer 16

done post XLA
using patient’s tooth
patient doesnt have to leave with a gap

Question 17

what is an indirect bridge

Answer 17

lab formed
wing finish 0.5mm supragingivally

Question 18

what preparation is required for an adhesive bridge (if needed)

Answer 18

180 wrap around
chamfer margin 0.5mm supragingivally
rest seats on posterior teeth

Question 19

what retainers are used for resin bonded bridges

Answer 19

CoCr or NiCr
sanblasted by lab to increase bond of cement

Question 20

what is an advantage of conventional bridgework

Answer 20

more robust
used in larger spans
maximum retention and strength

Question 21

what are disadvantages of conventional bridgework

Answer 21

more destructive to tooth tissue
preparation is difficult
removal of tooth tissue
parallel tooth preparation required

Question 22

what are the five aspects of pontic design

Answer 22

wash through
dome shaped
modified ridge
ridge lap
ovate

Question 23

what materials can be used for abutment teeth crowns in conventional bridges

Answer 23

all metal - gold, nickel, CoCr, stainless steel
metal ceramic
all ceramic - zirconia, lithium disilicate

Question 24

what materials may be used for crowns

Answer 24

gold type II alloy
paladium alloy
base metal alloys (nickel and chromium)
ceramic
stainless steel (paediatric)

Question 25

when are crowns used

Answer 25

to protect weakened tooth structure to improve aesthetics for retainers in bridgework when indicated by RPD design to restore tooth function

Question 26

what are the 6 principles of tooth preparation

Answer 26

preserve tooth structure retention and resistance structural durability marginal integrity preserve periodontium aesthetics

Question 27

what does under preparation for a crown result in

Answer 27

poor aesthetics overbuilt crown with periodontal and occlusal consequences

Question 28

what does overpreparation of a tooth for a crown result in

Answer 28

pulp and tooth strength being compromised

Question 29

what is the ideal design of a crown to allow retention and resistance to unwanted forces

Answer 29

inclination of opposing walls 6 degrees limit number of paths of insertion

Question 30

how is the tooth prepared to be structurally durable for crown application

Answer 30

occlusal reduction functional cusp bevel axial reduction

Question 31

for metal ceramic crown preparations on posterior teeth what is the occlusal reduction required

Answer 31

2.5mm

Question 32

what is the occlusal reduction required for metal crowns

Answer 32

1-1.5mm

Question 33

what margin is required for metal ceramic crowns

Answer 33

1.5mm chamfer margin

Question 34

what occlusal reduction is required for all ceramic crowns

Answer 34

2.5mm

Question 35

where should margins of crown restorations be placed to preserve the periodontium

Answer 35

smooth and fully exposed to cleansing action where the dentist can finish them and patient can clean them at the gingival margin where possible

Question 36

what is the axial reduction, occlusal reduction and finish line for a metal crown

Answer 36

0.5mm axial 1.5 functional cusp 0.5 non-functional cusp chamfer

Question 37

what is the axial reduction, occlusal reduction and finish line for ceramic crowns

Answer 37

1mm axial 1.5mm functional cusp 1mm non-functional cusp shoulder (1mm)

Question 38

what is the axial reduction, occlusal reduction and finish line for a metal ceramic crown

Answer 38

1.3mm axial 1.8mm functional cusp 1.3 non-functional cusp chamfer margin

Question 39

what are the stages in tooth preparation for a metal ceramic crown

Answer 39

occlusal reduction separation buccal reduction (in 2 planes) palatal/ lingual reduction shoulder/ chamfer finish check occlusal surface and clearance

Question 40

what are three treatment objectives of treating an endodontically treated tooth

Answer 40

remain tooth in arch maintain coronal seal of root canal system protect and preserve remaining tooth structure

Question 41

what is a post

Answer 41

peg or pin for fastening an artificial crown or core onto natural tooth root

Question 42

when are posts required

Answer 42

when three walls are lost (MODB/L cavity) no walls remaining

Question 43

what is the minimum thickness of a cavity wall to determine resistance to functional loads

Answer 43

1mm

Question 44

what is a ferrule

Answer 44

2-3mm coronal dentine remaining should not be less than 1.5mm

Question 45

what is the function of a ferrule

Answer 45

reduces stress which otherwise would cause root fracture

Question 46

what are the dimensions of an optimal post

Answer 46

1: ratio with crown or 2/3rd root length 4-5mm GP left at apex no more than 1/3 of root diameter placed in straight part of canal

Question 47

what materials can be used for posts

Answer 47

metal - stainless steel, titanium, cast metal non-metal - glass fibre, cement fibre

Question 48

what are cast posts

Answer 48

custom made posts to follow canal curvature requires extra lab and clinical stage

Question 49

what are fibre posts

Answer 49

pre-formed posts tooth coloured compatible with adhesive systems

Question 50

when would a fibre post be used as opposed to cast post

Answer 50

for a fibre post there must be 2-3mm remaining supra-gingival tooth structure fibre posts cannot be used in patients with paranfunctional habits or overbites

Question 51

what is the mode of failure for 1) cast posts and 2) fibre posts

Answer 51

1) fracture roots 2) debond at post-cement interface leading to caries

Question 52

what is the downside of tapered posts

Answer 52

must be cement retained wedging effect

Question 53

what is the downside of parallel posts

Answer 53

more tooth tissue removed

Question 54

what are three aspects of an optimal post design

Answer 54

parallel sided - avoids wedging non-threaded - avoids installation stress cement retained - cement distributes masticatory forces

Question 55

what types of cements can be used for cementing posts

Answer 55

GIC adhesive resin cement RMGIC

Question 56

what are the properties of adhesive resin cements in post placement

Answer 56

greater retention higher compression strength premature setting may occur before post fully seated

Question 57

what are the properties of GIC as a cement for post placement

Answer 57

weak chemical bond to dentine easier retrievability fluoride release but requires several days to reach max strength

Question 58

what are the properties of RMGIC as a cement for post placement

Answer 58

insoluble good retention but expands with time

Question 59

what is polyvinylsiloxane an example of

Answer 59

elastomeric material

Question 60

what are the three viscosities PVS has

Answer 60

light bodied medium bodied heavy bodied

Question 61

what forceps are used with articulating paper

Answer 61

millers forceps

Question 62

what are two ways an apex locator reading can be affected

Answer 62

fluid within the canal poor contact point with canal walls