Restorative Dentistry Flashcards

1
Q

pt lost a tooth, needs space filled. what options available to replace space now? (3)

A
  • natural tooth pontic
  • composite (free hand or crown former)
  • acrylic denture tooth
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2
Q

When adding a natural tooth pontic and additional retention needed, embed ____ on lingual surface. (3)

A
  • fiber reinforced ribbon
  • ortho wire
  • wire mesh
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3
Q

How is a Rochette bridge retentive? (3)

A
  • micromechanical retention
  • has countersunk holes within wing
  • allow retentive composite plugs/rivets to form when cemented
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4
Q

what are the cons of Rochette bridges? (2)

A
  • thick wing - affect occlusion
  • poor retention rate
  • fracture prone
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5
Q

Difference between adhesive resin luting cement and non-adhesive resin luting cement

A

adhesive can bond to metal in addition to etched tooth tissue.

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6
Q

adhesive luting cement bonds better with what sort of metal?

A

non-precious metal

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7
Q

give examples of

  • non precious metal
  • precious metal
A

CoCr
Stainless Steel
Nickel

Precious
- gold

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8
Q

What is done to improve bond strength of adhesive luting cement to precious metal alloy? (5)

A
  • Sandblasting with 50 micrometer alumina (most convenient and common)
  • Heat Tx and oxide formation
  • Silicate coating
  • Tin plating
  • Application of metal primer
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9
Q

what tooth preparation can be considered when doing a RBB? (3)

A

cingulum rest
cervical chamfer
occlusal rest (for posteriors)

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10
Q

if no prep RBB is done, what can be incooperated to help locate precise area of cementation? (2)

A

seating lug

incisal extension

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11
Q

what is the issues with cementing RBB on central incisors? (1)

A

metal wing can shine through

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12
Q

what is the issues with cementing RBB on canines? (3)

A
  • affect canine guidance

- mesial contact point on 3 is close to gingival margin (poor OH, connector too narrow)

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13
Q

what special prep is required for canines to be abutments for RBB? (1)

A

prep of guide plane on mesial surface

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14
Q

what is Ante’s law? (3)

A
  • combined pericemental area of abutment
  • must be equal or more to
  • the pericemental area of the teeth to be replaced.
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15
Q

what is Tarnow’s rule? (3)

A

distance between contact point and interproximal osseous crest has to be 5mm or less for complete fill of gingival embrasure

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16
Q

an abutment supporting 2 pontics (1 on both sides). What is this kind of abutment called?

A

Pier abutment

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17
Q

what is a spring cantilever? (3)

A
  • typically uses 6 as abutment
  • pontic on 1s or 2s.
  • stainless steal L shaped connector
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18
Q

spring cantilevers have become obsolete now cuz of the availability of what treatment option?

A

implants

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19
Q

what is the benefits of a fixed-movable bridge? (2)

A
  • allow movements along long axis of tooth

- does not require prep to be parallel

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20
Q

what is the ideal taper for a crown/bridge?

A

10-15 degrees

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21
Q

for a fixed-fixed bridge, what are the tooth prep rules? (3)

A
  • tapered
  • parallel to each other
  • no undercuts
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22
Q

name 4 pontic designs.

A
  • modified ridge lap
  • saddle
  • ovate / dome
  • sanitary
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23
Q

indications for a SANITARY pontic design (3)

A
  • posterior teeth (not in smile line)
  • easy cleaning
  • used primarily for stabilising occlusion
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24
Q

which pontic design is most popular amongst patients? why?

A
  • saddle

- has a similiar profile to natural teeth with realistic “feel”

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25
which pontic design is most desired by dentist? why?
- modified ridge lap - easy to clean - realistic appearance
26
when aspect of the occlusion is checked before fitting bridge? (2)
in ICP - abutment and pontic should have contacts in excursive movements - involve abutments only
27
what is the tooth prep thickness for veneers?
0.5 - 0.75mm
28
for a veneer prep, what sort of bur finish should be on the labial surface?
chamfer finish
29
name the 4 types of veneer incisal preps.
- feather edge - incisal overlap - window - incisal bevel
30
during veneer fabrication, why is glaze porcelain applied to the refractory die model? (1)
to allow space for luting cement
31
How can we create a rough fit surface on a veneer would allow better bond? (2)
- sandblasting | - use of hydrofluoric acid gel
32
what are the steps on veneer cementation? (6)
- apply silane coupling agent + air dry - cellulose strip other teeth - etch, rinse, dry, bond cure tooth - place resin luting cement - seat veneer - remove excess
33
ceramic try-in will look lighter when no try-in paste or definitive luting cement used, why? (2)
- with cement, more light is transmitted through veneer. | - without it, more light is transmitted.
34
when would a gold veneer be considered? (2)
- for palatal coverage | - erosion?
35
what does composite consist of? (3)
- Resin (dimethycrylate, ie BisGMA) - Filler particle (quartz, silica) - Barium (radio-opaque property)
36
what are the 2 types of composites?
hybrid | low shrink composites
37
after curing composite, it becomes smaller, what is this called?
polymerization shrinkage
38
how do you reduce polymerization shrinkage? (3)
place composite in increments | pre-heat composite
39
what is the C factor in composite?
configuration factor - ratio of bonded to unbonded surface area - lower C factor = lower shrinkage
40
why is RMGI cores is avoided for all ceramic crowns?
RMGI undergoes hygroscopic expansion
41
what does amalgam consist of? (4)
- mercury - silver-tin alloy - copper - palladium
42
what is the benefit of high copper amalgam? (3)
- less deformation - stronger in compression - reduced potential for corrosion
43
what is galvanic corrosion in dentistry? (3)
- occurs when 2 disimiliar metals (amalgam and gold fillings) - immersed in a conductive solution (saliva) - and are electrically connected.
44
Why copper amalgam has lower potential for corrosion than normal amalgam? (1)
absence of tin-mercury gamma 2 phase.
45
when tooth prepping for a crown, the aim is to create 2 forms. What are the 2 forms?
retention form | resistance form
46
what is retention form? (1)
prevents the displacement of restoration along path of insertion.
47
what is resistance form? (2)
- prevents dislodgment of restoration by forces directed apically or oblique direction. - prevents movement of restoration under occlusal forces
48
how is retention form achieved? (3)
total occlusal convergence (TOC) - is the angle of convergence of 2 opposing walls - ideal 4-10 degrees. taper - ideal 2-5 degrees (which gives the ideal TOC)
49
how is resistance form achieved? (3)
total occlusal convergence - ideal 4-10 degrees height of preparation (parallel belt) - shorter the better - posterior more resistance than anterior
50
what is a telescopic crown?
used as abutment for fixed prosthesis.
51
what is the advantage of using gold as restorative material? (4)
- high cast accuracy - require less tooth prep - high strength - highly polished (less abrasive to opposing teeth)
52
ceramic as a restorative material - pros (2) - cons (3)
pros - best aesthetics - hard and high wear resistance cons - brittle - rely mostly on luting cement for retention (tapered preps) - abrasive to opposing dentition when glaze is lost.
53
methods of making indirect restorations - traditional (2) - modern (1)
traditional - lost wax technique (for gold) - refractory die (for ceramic) modern - CADCAM
54
what is an Iwanson gauge? (1)
used to measure crown thickness
55
what is the minimal thickness required for the following restoration materials. - high copper amalgam - cast metal - porcelain - composite
- high copper amalgam: 1.5mm - cast metal: 1mm - porcelain: 2mm - composite: 2.5mm
56
how to achieve retention form for amalgam placement? (3)
create - dovetail - grooves - undercuts
57
dentine - types (3) - when do they form?
Primary - dentine before root completion 2* - dentine after root completion 3* - reaction to pathology/assault
58
Tertiary dentine - types (2) - what is it (2)
reactionary - dentine secreted by pre-existing odontoblast reparative - dentine secreted by newly differentiated odontoblast
59
ICDAS - what is it? - classes? (6)
international caries detection and assessment system class - 0: sound 1: first visual change in enamel 2: distinct visual change in enamel 3: localised enamel breakdown (no visible dentin) 4: underlying dark shadow from dentine 5: distinct cavity + visible dentin 6: extensive distinct cavity + visible dentin
60
temporary fillings - types (3) - brand names (3) - advantage? (3)
GI (FUJI) - adhesive ``` ZnO Eugenol (Kalzinol) - anti-inflammatory and LA effect ``` ZnO (Cavit) - undergoes linear expansion from water sorption
61
etching for composite filling - what is used? - how to use? - why is it used? (2)
30% phosphoric acid dry tooth + apply for 15s - removes smear layer - opens up collagen fibers and dentinal tubules
62
prime for composite filling | - why? (1)
increase wettability of surface
63
bond + curing in composite fillings - how long to cure? - what happens? (2)
20s - forms resin tags with fibers in tubules - forms links between resin primer and composite
64
what is chelation in dentistry? (2)
chelating agent (EDTA) binds with calcium and brings it out of the canal.
65
ceramic restorations - types (3) - describe (2 each)
glass ceramic - also called feldspathic porcelain - most aesthetic used in veneers particle filled glass - also called lithium disilicate - most common - example is Emax polycrystalline - strongest - example is Zirconia
66
what is a Lucia Jig? (3)
used to stabilise mandible in a harmonious position - accurate bite reg - deprogrammer for bruxism
67
% of teeth over-erupt (with no opposing dentition)
85%
68
what is a central bearing apparatus? (2)
- requires a Gerber condylator | - shows centric relation and retruded contact position