Restorative Skills Flashcards

1
Q

why are cavities restored ?

A

to restore integrity, function and aesthetics

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2
Q

what do extensive amalgam restorations involve ?

A

rebuilding cusps, provide auxiliary retention

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3
Q

how do EAR’s compare to cast restorations ?

A

EAR’s are less invasive, expensive and time consuming

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4
Q

what is retention form ?

A

the features of the cavity that prevent withdrawal of the restoration in the long axis of the preparation

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5
Q

what is resistance form ?

A

the features preventing dislodgement of the restoration under all other forms of loading

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6
Q

what is auxiliary retention ?

A

supplementary retention required for extensive restorations

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7
Q

how is auxiliary retention achieved ?

A

cavity design features, pins, adhesives

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8
Q

how is additional resistance form achieved in EAR’s ?

A

boxes, axial grooves, slots, pits

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9
Q

what should the dimensions of slots and pits be in EAR’s ?

A

depth no greater than 1mm, width slightly greater than diameter of instrument used

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10
Q

what are the 3 types of pins used in EAR’s ?

A

cemented pins, friction grip pins, self threading pins (most retentive)

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11
Q

when should a pin be used in an EAR?

A

1 pin for each missing cusp, line angle and proximal surface

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12
Q

specifically where should pins be placed ?

A

1-2 mm inside DEJ
2mm into dentine
2mm into amalgam
2mm from opposing tooth (upper/lower)

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13
Q

what are the disadvantages of using pins in EAR’s ?

A

weaken tooth structure and the restoration
possible fracture of tooth structure
internal stresses
incorrectly placed pins can perforate the pulp or periodontal tissues
pins too close to pulp will cause post op sensitivity

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14
Q

which adhesives can be used to retain EAR’s?

A

4META (amalgambond)

MDP (panavia)

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15
Q

what are the advantages of using adhesives to retain EAR’s ?

A

increase retention

conserve sound tooth structure

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16
Q

in which 2 ways can restorations fail ?

A

new disease - secondary/recurrent caries

technical failure

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17
Q

what are the disadvantages of replacing defective EAR’s?

A

inadvertent removal of tooth structure,
increased cavity size,
risk of damage to pulp,
development of clinical symptoms

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18
Q

why is to often better to repair EAR’s rather than replace them ?

A

conservative, quicker, cheaper, LA may not be required

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19
Q

which bur is used to prepare a class III cavity ?

A

520 round bur

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20
Q

what are the advantages of bevelling enamel margins in class III cavities ?

A

provides larger surface area for bonding,
reduces micro-leakage,
cross cuts prisms and gives better etch pattern,
blends composite onto surrounding tooth surface

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21
Q

what are the disadvantages of bevelling enamel margins in class III cavities ?

A

damage to adjacent tooth,
lacerate gingivae,
increase in subsequent cavity size

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22
Q

what are the clinical recommendations for bevelling enamel margins in class III cavities ?

A

if labial margin of cavity is visible

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23
Q

when is a class IV restoration indicated ?

A
trauma resulting in fracture of the crown,
progress of a class III to involve the mesial edge
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24
Q

what angle do incisors fracture across the crown after trauma ?

A

45 degrees

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25
Q

what are the problems following trauma ?

A

root fracture may have occurred,

adjacent and opposing teeth may also have been fractured

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26
Q

how should the labial margin of a class IV be prepared ?

A

a D and Z bur is used to create a scalloped bevelled margin 1mm in width

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27
Q

where do class V cavities develop ?

A

cervical third of all tooth types

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28
Q

why may a class V restoration be required ?

A

caries due to poor plaque control,
abrasion due to inappropriate tooth brushing methods,
abfracture - occlusal stresses concentrate at the thin enamel near the enamel cementum junction causing fracture of the brittle enamel

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29
Q

what should be used to prepare the class V cavity before filling and why ?

A

oil and glycerine free prophylaxis paste to optimise the bonding of the filling material,
paste should also be free of fluoride as this may adversely affect bonding of the filling material

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30
Q

what is in a compomer ?

A

aluminosilicate glass and acid polymerisable resin

31
Q

what is the resin in a compomer ?

A

tetra carboxylic acid butane polymerised by hydroxyethyl methacrylate

32
Q

what can improve the bond strength of compomer to enamel ?

A

non rinse conditioner (NRC),

phosphoric acid etchant

33
Q

what is NRC?

A

mixture of maleic and polyacrylic acids

34
Q

how should enamel and dentine be prepared for compomer bonding ?

A

etched using total etch technique and bonding resin applied

35
Q

what increments should compomer be cured in ?

A

3mm

36
Q

what happens once the finished compomer restoration absorbs water ?

A

the glass ionomer reaction proceeds via the ionised pendant groups of carboxylic, these will react with the filler particles of alumina silicate glass
this allows some ionic interchange with the tooth surface for bonding and also release fluoride

37
Q

what are the indications for a porcelain crown ?

A
heavily restored tooth,
trauma resulting in fracture,
hereditary and acquired hypoplasia,
tooth wear,
alter size and shape of tooth,
in combination with bridges and partial dentures,
improve appearance of anterior teeth
38
Q

what are the alternative treatments to porcelain crowns ?

A

bleaching discoloured teeth,
restore with tooth coloured filling materials,
veneers

39
Q

what bur should be used for the incisal reduction in a porcelain crown ?

A

554

40
Q

how much incisal reduction should be created for a porcelain crown ?

A

1-2mm

41
Q

which bur should be used for the labial reduction in a porcelain crown ?

A

5013

42
Q

what is the depth of the labial reduction on a porcelain crown ?

A

1mm

43
Q

which bur is used for the axial reduction in a porcelain crown ?

A

5013

44
Q

what should the diverging angle of the sides of the porcelain crown prep be ?

A

3-6 degrees

45
Q

what is the finish line for a porcelain crown ?

A

1mm shoulder

46
Q

which bur should be used to complete the palatal reduction for a porcelain crown ?

A

5013 bur

47
Q

which bur is used to complete the cingulum reduction for the porcelain crown ?

A

285 rugby ball bur

48
Q

what is the difference between a temporary and provisional crown ?

A

temporary crown - short term while permanent crown made

provisional crown - lasts for longer period while other assessment of teeth carried out

49
Q

what are the requirements of temporary restorations?

A

biological,
mechanical,
aesthetic

50
Q

what are the biological requirements of a temporary crown ?

A

protect prepared dentine,
prevent gingiva overgrowing prep margins,
prevent over eruption or tilting of prepared tooth

51
Q

what are the indications for PFM crowns ?

A

heavily restored tooth,
porcelain crown repeatedly fractures,
occlusion is unfavourable - deep overbite and minimal overjet,
in conjunction with bridge or partial denture construction

52
Q

what is the reduction of the functional cusp for a PFM?

A

1.5mm

53
Q

what is the reduction of the non functional cusp for a PFM ?

A

1mm

54
Q

which bur is used to complete the occlusal reduction for a PFM ?

A

554

55
Q

what is the buccal finish line for a PFM ?

A

1.3 mm shoulder

56
Q

what is the palatal/lingual finish line for a PFM?

A

champher

57
Q

which bur is used to complete the chamfer ?

A

877K

58
Q

what are the advantages of the wingless PFM design ?

A

easier to prepare,

less chance of leaving undercut

59
Q

what are the disadvantages of the wingless PFM design ?

A

less resistance form,

not as conservative of tooth structure

60
Q

how many mm clearance should dentine pins be placed from the edge of the tooth?

A

3mm

61
Q

how much dentine should surround the pin ?

A

1mm

62
Q

what thickness of dentine is required for pin placement ?

A

2.5mm

63
Q

Describe the international caries detection and assessment system

A
0 sound tooth surface 
1 first visual change in dry enamel
2 distinct visual Change I wet enamel 
3 localised enamel breakdown
4 underlying dark shadow from dentine 
5 district cavity with visible dentine
6 extensive distinct cavity
64
Q

Describe the criteria for scoring bite wing radiolucencies

A

C0 no radiolucencies
C1 radiolucency evident in outer half of enamel
C2 radiolucency evident in inner half of enamel
C3 radiolucency extends beyond adj
C4 radiolucency evident within outer third of dentine
C5 radiolucency extends to inner third of dentine, may reach pulp

65
Q

When is pulpal extirpation indicated ?

A

Alleviation of pain of pulpitis or acute peri apical periodontitis and stabilise tooth in short term

66
Q

When is indirect pulp cappings or stepwise technique indicated ?

A

Where likelihood of pulpal exposure eg 3/4 of dentine thickness demineralised

67
Q

Why are restorations polished ?

A

Improve marginal integrity and longevity
Less destruction to opposing dentition,
Minimise plaque and gingival irritation,
Eliminate overhangs
Increased reflective and refractive index

68
Q

What is the order of polishability of composites ?

A
Least
Microhybrids, 
Nanohybrids, nanofills 
Microfills
Most
69
Q

What do high speed abrasives produce ?

A

Quick abrasion,
High heat,
Little wear of abrasive,
Smooth surface

70
Q

What do low speed abrasives produce ?

A

Slower abrasive action,
Less heat,
Wear of abrasive particles,
Deeper scratches

71
Q

What are the types of dental abrasives ?

A
Emery,
Garnet,
Pumice,
Keiselguhr,
Carbides,
Diamond,
Sand
72
Q

What does polishing produce ?

A

Smooth reflective surface,
Beilby layer,
Surface flow

73
Q

What are the types of polishing agents ?

A
Whiting,
Rouge,
Tripoli,
Tin oxide,
Chromium oxide
74
Q

What is burnishing ?

A

Smoothing by rubbing metal against metal