Jane's Wiggs Chapter 17 and 18 - Operative Dentistry Flashcards
1
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What class of lesion is this in GV Blacks modified cavity preparation classification system?
A
Class 1 - pit and fissure location, any tooth
2
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What class of lesion is this in GV Blacks modified cavity preparation classification system?
A
Class 2 - lesions on proximal surfaces ***ONLY MOLARS AND PREMOLARS***
3
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What class of lesion is this in GV Blacks modified cavity preparation classification system?
A
Class III - Proximal surface, not including incisal edge *** ONLY INCISORS AND CANINES*
4
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What class of lesion is this in GV Blacks modified cavity preparation classification system?
A
Class IV - lesions of the proximal surface involving the incisal edge ***ONLY CANINES AND INCISORS***
5
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What class of lesion is this in GV Blacks modified cavity preparation classification system?
A
Class V - Facial and lingual surfaces of all teeth, excludes pits and fissures
6
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What class of lesion is this in GV Blacks modified cavity preparation classification system?
A
Class VI - defect of the incisal edge or cusp on any tooth (not in GV blacks original classification)
Careful to differentiate from class IV - proximal between incisors or canines, but affecting the incisal edge
7
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the three categories, and what does each mean in the ELEMENTARY CAVITY CLASSIFICATION?
A
Simple - one wall affected
compound - two walls affected
complex - three walls affected
8
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
How many dentinal tubules are there per square mm of SURFACE dentin?
A
30,000 - 40,000
9
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Compare and contrast pulp a-delta and c-fibres with regard to size, myelin, speed of conduction and type of pain
A
A delta: Large, myelinated, fast conduction, sharp pain
C-fibres: Small, non- or minimally myelinated, slower conduction, dull, throbbing, acching pain
10
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
According to Brannstrom, what is suspected to be the main cause of eliciting dental pain?
A
Rapid flow of fluid in dentinal tubules
11
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Name the cell layers inside the tooth pulp, beginning at the dentin and moving inwards
A
Odontoblast layer
Cell free zone (of Weil)
cell rich zone (of Hohl)
pulp core (not mentioned in Wiggs, but mentioned elsewhere)
12
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What is sclerotic dentin?
A
Dentin that is more highly mineralized in response to a dead tract (unoccupied tubule) left vacant by a dead odontoblast.
13
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What is a clinical sign of sclerotic dentin visible to the naked eye?
A
highly translucent dentin
14
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What are they two types of tertiary dentin, and what is the difference?
A
Reactionary - made by an existing odontoblast in response to an insult
Repairative - newly differentiated odontoblast-like cell from a local stem cell precursor
15
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Name the walls of the cavity prep depicted by each letter.
A
Uses human terms, substitue bucal for facial.
Best way for me to remember is that wall is named for what it’s made out of…
16
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
What is the difference between a line angle and a point angle?
A
Line angles are where 2 walls intersect, point angles are where 3 walls intersect.
17
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Name the following line and point angles.
A
angles are named by the 2 or 3 surfaces that make them
18
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Which is considered more important in modern dentistry: extension for prevention or conservation of tooth structure?
A
conservation of tooth structure. Extension for prevention is dead.
19
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Name all of the forms (7) in G.V. Blacks cavity preparation steps:
A
- Outline form
- Resistance form
- Retention form
- Convenience form
- Pathology removal form
- Wall form
- Preparation cleansing form
20
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the outline form for cavity preparation
A
establishing the external and internal dimensions of the preparation
21
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the resistance form for cavity preparation:
A
Shaping the preparation to Resist fracture of the material and tooth
22
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the retention form for cavity preparation
A
Design of the preparation so that the restorative material stays put. (i.e. undercuts etc for non-adhesive materials)
23
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the convenience form for cavity preparation:
A
Shaping the preparation for ease of access in placement, shaping and finishing
24
Q
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the Pathology removal form for cavity preparation:
A
shaping the prep to remove all diseased dental material.
25
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the wall form for cavity preparation:
refinement in shaping to remove all unsupported enamel rods, and smooth rough outlines
26
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the preparation cleansing form for cavity preparation:
Final shaping and removal of debris etc before placing restoration
27
According to Wiggs Chapter 17 (Restorative Dentistry),
What is a pulp capping material and when is it indicated?
What is the difference between direct and indirect pulp capping?
At what distance from the pulp should indirect pulp capping be performed
a medicament placed over the pulp area. Use MTA or CaOH.
indirect capping is if the pulp has not quite been exposed. Direct capping is when the pulp has been exposed.
within 0.5 mm of the pulp pulp capping amterial should be placed
28
According to Wiggs Chapter 17 (Restorative Dentistry),
What is the chemical reaction on which most light cure products are based?
bis‐phenol A and a glycidyl methacrylate, commonly abbreviated to bis‐GMA
29
According to Wiggs Chapter 17 (Restorative Dentistry),
What is the wavelength of light presently used to cause light curing?
460-480 nm
30
According to Wiggs Chapter 17 (Restorative Dentistry),
What is the most common activator in chemically cured products?
Benzoyl peroxide
31
According to Wiggs Chapter 17 (Restorative Dentistry),
What is the most common activator in visible light cured products?
camphoroquinone
32
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the 4 main components in a dental composite?
inorganic fillers (mainly quartz/ glass particles),
organic resins (the glue),
coupling agent (the link or bond between the glue and the glass),
the initiator–accelerator system.
33
According to Wiggs Chapter 17 (Restorative Dentistry),
What do inorganic fillers do in a dental composite (6)?
Strengthen the matrix,
increase hardness
reduce wear,
reduce shrinkage,
reduce thermal expansion
Improve handling (make product thicker) and radiopacity
34
According to Wiggs Chapter 17 (Restorative Dentistry),
What is a coupling agent?
coating applied to inorganic fillers essentially so they will stick to the resin. Usually **Silane**
35
According to Wiggs Chapter 17 (Restorative Dentistry),
What is a major problem with methacrylate based polymerization systems?
Shrinkage! (is it cold in here?)
36
According to Wiggs Chapter 17 (Restorative Dentistry),
What benefit do newer silorane based products offer? How is their chemical reaction different?
reduced shrinkage
chemical reaction is a cationic ring opening which represents significantly less shrinkage.
37
According to Wiggs Chapter 17 (Restorative Dentistry),
What is a main esthetic advantage of a restorative material with smaller particles?
They are highly polishable and very esthetic
38
According to Wiggs Chapter 17 (Restorative Dentistry),
What are main disadvantages (4) of a restorative material with a lower quantity of inorganic fillers?
higher coefficient of thermal expansion,
increased shrinkage during polymerization
may absorb more water
less fracture and wear resistant
39
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the benefits of a nanofilled composite?
maintain strength of a microhybrid, but the esthetics of a microfill composite
40
According to Wiggs Chapter 17 (Restorative Dentistry),
What is done to make flowable composite flowable?
more resin, less filler.
41
According to Wiggs Chapter 17 (Restorative Dentistry),
How much shrinkage is expected when light curing a composite resin?
3% linear shrinkage and 1.5 % volume shrinkage
slightly more with flowable products
42
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the weakest points of the bond of a restoration?
cervical enamel cavosurface and the dentin interface
43
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the components of a glass ionomer cement?
aluminosilicate glass powder (calcium or strontium fluoroaluminosilicate (FAS) glass)
polyalkenoic acid (polyacrylic acid),
water
tartaric acid
Barium, zinc oxide, and other metals are added to the GIC to provide radio‐opacity.
44
According to Wiggs Chapter 17 (Restorative Dentistry),
How does a GIC bond to the tooth?
Chemical bond
bond to dentin by forming ion salts to calcium in the tooth
45
According to Wiggs Chapter 17 (Restorative Dentistry),
What are main benefits of GIC?
Release fluoride
biocompatible with pulp
maintain a tight marginal seal (coefficient of thermal expansion similar to tooth)
46
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the main drawbacks to GIC?
technique sensitive
do not bear stress and wear as well as other materials
47
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the GIC chemical reaction
FAS Glass + Polyacrylic acid --\> Acid base reaction
some glass dissolves, releases alumina, strontium, fluoride
remaining glass embedded in silica matrix;
There is an ionic interaction with the exchange of calcium and/or phosphate ions from the hydroxyapatite, and calcium ions increase in the GIC, indicating chemical bonding.
48
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the 4 types of GIC?
Type I Luting cements
Type II Esthetic restorative
Type III Bases and liners
Type IV Admixtures
49
According to Wiggs Chapter 17 (Restorative Dentistry),
What is different about type I GICs?
luting cements, finely ground glasss and film thickness \<25 um
50
According to Wiggs Chapter 17 (Restorative Dentistry),
When are type II GIC's indicated?
As a restorative material when fluoride release is desirable
51
According to Wiggs Chapter 17 (Restorative Dentistry),
What defines a Type IV GIC and what is a drawback of type IV GIC's for their intended use?
Type IV have a substantial metal component - gold, silver or amalgam.
Used for temporary restorations or buildups
significantly weaker than other materials used for this purpose
52
According to Wiggs Chapter 17 (Restorative Dentistry),
What are benefits of RMGIC's over the traditional GIC's?
Short/controlled setting time
53
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the two setting reactions in a RMGIC?
Polyacrylic acid + FAS Glass reaction
AND
free radical methacrylate polymerization
Essentially both the reaction for GIC and for composite resin
54
According to Wiggs Chapter 17 (Restorative Dentistry),
What is the difference between a compomer and a Giomer?
gi-omer has prereacted glass, so releases fluoride, but it more like a composite.
compomer has mostly properties of a composite resin, but with glass particles and releases some fluoride
55
According to Wiggs Chapter 17 (Restorative Dentistry),
Name the bond mechanism for the following restorative products:
GIC, RMGIC, composite resin, amalgam
GIC - chemical
RMGIC - chemical
CR - micromechanical
Amalgam - mechanical retention (no bond)
56
According to Wiggs Chapter 17 (Restorative Dentistry),
Describe the effect of acid etching on enamel?
Acid conditioning of the enamel causes enamel prisms and interprismatic enamel to dissolve and a micro retentive surface is created
57
According to Wiggs Chapter 17 (Restorative Dentistry),
How many generations of dentin bonding have there been?
8
58
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the essential components of any modern dentin bonding system?
etch, primer, adhesive
59
According to Wiggs Chapter 17 (Restorative Dentistry),
How many steps are there in a 4th generation system?
3 steps:
Acid etch
primer (usually hydroxyethyl methacrylate or HEMA)
bonding agent (bis‐GMA plus photoinitiator)
60
According to Wiggs Chapter 17 (Restorative Dentistry),
What major change was made between a 4th and 5th generation bonding agent?
Primer and adhesive are combined in 1 bottle, which reduces to 2 steps (acid etch, then primer/adhesive application)
61
According to Wiggs Chapter 17 (Restorative Dentistry),
What are the two types of 6th generation material bonding systems?
Type 1 - self etching primer applied, followed by the adhesive. No rinsing required
Type 2 - mix 2 products before applying, but it is a self-etching adhesive product. no rinsing.
62
According to Wiggs Chapter 17 (Restorative Dentistry),
What is different about 6th generation agents with regards to the smear layer?
incorporated as a hybrid layer instead of being removed
63
According to Wiggs Chapter 17 (Restorative Dentistry),
What is a drawback to the 6th generation systems?
weaker bond strength than 5th gen.
64
According to Wiggs Chapter 17 (Restorative Dentistry),
How many steps are required in 7th and 8th generation bonding systems?
1
Etch, primer and bonding agent all in the same product. No rinsing or washing.
65
According to Wiggs Chapter 17 (Restorative Dentistry),
What is different about 8th generation systems over all others previously marketed?
has nanofiller incorportated as a component. Still a 1 product, 1 step system similar to 7th generation with no rinsing.
66
According to Wiggs Chapter 17 (Restorative Dentistry),
What generation of bonding system has 3 steps?
4th generation
67
According to Wiggs Chapter 17 (Restorative Dentistry),
What generations may be 2 step systems?
Generation 5 - acid etch, then primer+adhesive in the same product
Generation 6, type I - self etching primer, then adhesive separately
(no rinsing)
Type II is mixing 2 products together before applying the mixture - self etching adhesive. Unsure if this is one or two steps
68
According to Wiggs Chapter 17 (Restorative Dentistry),
What are 6 principles for cavity prep design (not GV blacks forms)?
1) Cavosurface angles should be at a 90° or parallel to the enamel rods.
2) Designed so the dentinal tooth structure supports the restoration.
3) Preparation should be complete, but conservative in nature.
4) Consider retention based on restoration material. Only amalgam needs to incorporate retentive features
5) Protect the pulp - pulp capping or liner if indicated
6) where resto likely to be stressed, sufficient bulk for strength will be necessary.
69
According to Wiggs Chapter 17 (Restorative Dentistry),
List in order from Extra fine to extra course the colour bands of diamond burs?
FG diamond burs come in various levels of grit coarseness with
extra fine grit (yellow banded).
fine grit (red banded),
medium grit (blue banded),
coarse grit (green banded),
extra coarse grit (black banded),
N.B. - going fine to coarse same colour order as endo files, just no white
70
According to Wiggs Chapter 17 (Restorative Dentistry),
In which class of cavity preparations should the cavosurface margin be bevelled and why?
For class III, IV, V, VI
Will increase the surface area of enamel for bonding and also give a gradual change of composite to enamel
71
According to Wiggs Chapter 17 (Restorative Dentistry),
In which class of cavity preparations should the cavosurface margin **NOT** be bevelled and why (3)?
Class I and Class II.
not beneficial because the rods are already exposed.
Also if on occlusal surface, enamel is more wear resistant than restorative material
also bevel gives very thin edge of restoration which is prone to fracture on occlusal surface
72
According to Wiggs Chapter 17 (Restorative Dentistry),
Which class of preparations are bes managed with cast or milled restorations as opposed to direct restorations?
Class IV and VI - involve an occlusal edge
73
According to Wiggs Chapter 17 (Restorative Dentistry),
in Class V lesions, when would bevelling of enamel not be recommended?
when the margin is on cementum. bevelling only gives a benefit when it is on enamel.
74
According to Wiggs Chapter 17 (Restorative Dentistry),
What considerations must be taken in placing GIC restorations?
Very sensitive to moisture
75
According to Wiggs Chapter 17 (Restorative Dentistry),
What happens to GIC restorations contaminated early with moisture?
Dissolves the GIC and washes it out of the prep
76
According to Wiggs Chapter 17 (Restorative Dentistry),
What happens to GIC restorations when contaminated with moisture during setting?
cloudy spots at the points of contamination, which is due to **crazing or microcracks** in the restoration
77
According to Wiggs Chapter 17 (Restorative Dentistry),,
Once GIC is set, but not hard, what additional step must be taken?
protection from dehydration with a moisture barrier such as an unfilled resin.
78
According to Wiggs Chapter 17 (Restorative Dentistry),,
Rank the following in terms of bond strength:
GIC to enamel, Composite resin to enamel, GIC to dentin
GIC to dentin, GIC to enamel, Composite resin to enamel
79
According to Wiggs Chapter 18 (Crowns and prosthodontics),
Define convergance angle
The angle between two opposing axial walls of a preparation.
80
According to Wiggs Chapter 18 (Crowns and prosthodontics),
For crowns, what is the difference between resistance and retention?
Resistance is ability to resist occlusal forces (apical/oblique)
Retention is ability to resist tensile forces along the long axis (ie. mesial/distal/laterally directed force)
81
According to Wiggs Chapter 18 (Crowns and prosthodontics),
When crown prepping a vital tooth what can be done to protect the pulp from insult?
Temporary crown placement, or dentin bonding.
82
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What type of crown material is considered the gold standard in veterinary dentistry?
Cast metal crown
83
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What are the noble metals (7)?
Gold,
platinum,
palladium,
ruthium,
rhodium,
iridium,
osmium
84
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What non-noble metal is also included in precious metals? Why is it not noble in dentistry?
Silver
Corrodes in the oral cavity
85
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What is a high fusing metal and why is it used for a PFM (porcelain fused to metal) restoration?
Alloy which has a very high melting temperature.
Used because it will not melt or creep during repeated heating process needed to fuse the porcelain
86
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What is a high noble alloy?
Noble metal content ≥60% (gold + platinum
group) and gold ≥40%
87
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What defines titanium and titanium alloys?
\> = 85% titanium
88
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What defines a noble alloy?
Noble metal content ≥25%
89
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What defines a predominantly base alloy?
Noble metal content = 25%
90
According to Wiggs Chapter 18 (Crowns and prosthodontics),
what beneficial properties do predominantly base alloys have?
As a group they are much harder, stronger, and have twice as high an elastic modulus as do the high noble and noble metal alloys.
This latter property is advantageous because casting can be made thinner and still retain rigidity
91
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What must be the axial, incisal and occlusal reduction in order to properly fit a porcelain fused to metal crown, and why?
•The axial reduction with PFM needs to be in the range of 1.5 mm
The incisal reduction should be 2.0mm and occlusal 1.5 mm range
To allow for a 0.5 mm metal substructure and the 1 mm of porcelain needed to cover the metal esthetically.
92
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What is the benefit of a PFM restoration, what are the risks, and what happens if the porcelain fails?
Benefit is estietic
risk is fracture of the porcelain
if that happens, metal substructure should still be intact and protecting the tooth.
93
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What are the five guiding principles for crown preparation design?
preservation of tooth structure,
retention and resistance,
structural durability,
marginal integrity,
preservation of the periodontium.
94
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What are the 4 operator controlled factors related to retention and resistance?
convergence angle,
crown height,
auxiliary features,
freedom of displacement
95
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What concept is being illustrated here?
convergence angle
96
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What is the naturally occurring convergnece angle of the maxillary fourth premolar and mandibular first molar (from wisconsin paper)?
Max P4 - 43 deg
Mand M1 - 36 deg
97
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What are the average achievable convergance angles for the canine tooth in the Mesiodistal and faciolingual plane?
MD - 35 deg
FL 18 deg
98
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What key factor is unde the operators control and helps improve retention with unfavourable preparations?
choice of luting cement - resin based are very strong
99
According to Wiggs Chapter 18 (Crowns and prosthodontics),
How is the limiting convergence angle calculated?
CAlim = arcsin (H/D)
100
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What happens to CA lim when H/D is greater than 1?
mathematically there is no CAlim, and theoretically any convergence angle would provide retention (may not be true in practice)
Basically, if the prep is taller than it is fat, the crown can't be rolled off the prep
101
According to Wiggs Chapter 18 (Crowns and prosthodontics),
Define type I, type II, and type III Crown lengthening
Type 1 - gingivectomy
Type 2 - apically repositioned flap with osseous recontouring
type 3 - orthodontic extrusion
102
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What auxiliary feature can be added to crown preparations with unfavourable properties?
Axillary grooves
103
According to Wiggs Chapter 18 (Crowns and prosthodontics),
How do axillary grooves improve retention (2)?
Increases surface area for cement bonding
decreases the 'effective CA'
104
According to Wiggs Chapter 18 (Crowns and prosthodontics),
Describe freedom of displacement?
the number of geometrically possible ways that a restoration can be dislodged, including rotation if prep is close to cylindrical
105
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What is the difference between a shoulder margin and a radial shoulder margin for a crown?
radial shoulder has a rounded internal margin wheras a shoulder has a sharp margin.
Both have a 90 deg cavosurface margin.
106
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What is preferred margin configuration for veneer metal restorations?
Chamfer
107
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What margin may be better for a ceramic or PFM restoration?
Heavy chamfer
108
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What is bevelling with regards to crown preps and what is it's purpose?
Adding a bevel to the cavosurface margin, may improve the integrity of the margin
109
According to Wiggs Chapter 18 (Crowns and prosthodontics),
What type of cements create the highest degree of marginal integrity?
Resin based cements
110
According to Wiggs Chapter 18 (Crowns and prosthodontics),
Why should subgingival finish lines on crown preparation be avoided?
increased plaque accumulation,
gingival inflammation,
deep pocket formation,
attachment loss,
gingival recession,
(essentially periodontitis!)
and an increased chance of invading biologic width
111
According to Wiggs Chapter 18 (Crowns and prosthodontics),
When taking impressions, why should the impression be repeated if there is putty show through?
Exposed set putty creates a pressure spot that rebounds when the impression is removed and results in too small a casting
112
According to Wiggs Chapter 18 (Crowns and prosthodontics),
When mixing alginate what does the temperature of the water do?
cold water slows setting, warm water increases it
113
According to Wiggs Chapter 18 (Crowns and prosthodontics),
How quickly should alginate be mixed?
completely mixed with no lumps in less than 1 minute
