Restorative Flashcards
(149 cards)
1
Q
Amalgam composition
A
Mercury Tin Silver Copper Zinc
2
Q
What does tin do in amalgam?
A
Critical to setting reaction
Controls dimensional change
3
Q
What does copper do in amalgam?
A
Prevents corrosion
Reduces fracture
Eliminates Gamma 2
4
Q
What does zinc do in amalgam
A
Scavenger for oxygen
5
Q
What does mercury do in amalgam?
A
Wets alloy and initiates setting reaction
6
Q
What is the gamma 1 phase of amalgam?
A
Silver and mercury
7
Q
What is the gamma 2 phase of amalgam?
A
Tin and mercury
Responsible for early fracture and failure
8
Q
3 Types of Amalgam
A
Spherical: amalgamates more readily, less mercury required
Lathe-cut
Admixed: better proximal contacts
Both spherical and admixed are marketed today
9
Q
What is the amount of creep amalgam can have to be ADA certified?
A
Maximum 5% creep
Occurs under loading
Modern alloy should not have more than 1% creep
10
Q
Does amalgam or composite have more dimensional change?
A
Composite (2%)
Amalgam has 0.2%
11
Q
What is the only restorative material in which the marginal seal improves over time?
A
Amalgam
12
Q
What is the eta phase of amalgam?
A
Copper and Tin
13
Q
3 forms of mercury
A
Elemental: liquid at room temperature, used in amalgam
Organic: methyl mercury (most toxic) and ethyl mercury - formed in water/soil by bacteria, can build up in fish
Inorganic: enters air from mining or deposits, burning coal/waste
14
Q
Main human exposures to mercury
A
Mercury vapor from dental amalgam
Methyl mercury from seafood
Inorganic mercury from food
15
Q
Threshold for health hazards from air/mercury
A
5 g/m2 for adults
1 g/m2 for kids and pregnant women
This is well-below daily amalgam associated exposure
16
Q
What is the primary risk to dental personnel for use of amalgam?
A
Inhalation
17
Q
How to reduce plasma and urine mercury levels during dental restorations
A
Use rubber dam
Use high speed evacuation and water spray
Do not heat sterilize amalgam
More mercury removed when fillings are removed than when placed
18
Q
New England Children’s Amalgam Trial
A
534 children between 6-10 years of age with no prior amalgam
Assignment to amalgam (vs composite) associated with higher mercury level
No association with IQ, urinary albumin, general memory index or visuomotor composite
19
Q
Indications for Amalgam
A
Class II preparations that do not extend beyond the line angles
May be inappropriate for primary 1st molar in children 4 and younger
20
Q
Amalgam Preparation Design
A
Pulp floor depth 0.5mm into dentin
Isthmus 1/3 of intercuspal width
Carved anatomy should be shallow
Convergent walls occlusally
Broader proximal box at cervical portion than occlusal
Gingival wall is flat, not beveled
Axial wall 0.5mm into dentin with 1mm wide gingival seat
21
Q
Trituration of Amalgam
A
Under triturated (most serious error) appears dry and sandy, sets rapidly
Higher trituration speed gives less working time
Back-to-back restorations should be condensated simultaneously
22
Q
Amalgam longevity vs composite
A
Up to 7 times more need for repairs of composite compared to amalgam
Need for additional restorative treatment 50% higher with composites versus amalgam historically
23
Q
3 Phases in Composite
A
Resin (matrix)
Surface (interstitial or continuous) - binds to organic resin matrix to inorganic fillers
Dispersed (reinforcement, filler)
24
Q
Composite oligomers
A
All composite have dimethacrylate oligomer such as Bis-GMA, Bis-EMA6 (larger), siolorane monomer
Larger oligomers (TEGDMA or Bis-6) have less shrinkage
25
Filler sizes of composite
Microfilled: 40nm
Nanofilled: 20-75nm
Hybrid: 40nm and small particle (200-300nm)
Flowable: 45-75% filler
26
Does more resin result in more or less shrinkage?
More
27
What does larger particle size do? What does smaller particle size do?
```
Larger = strength
Smaller = polishability
```
Microfilled composites can achieve better polish more quickly; used for esthetic restorations
28
Indications for composite
Class I restorations
Class II restorations that don't extend beyond line angle (except when exfoliating in 1-2 ears)
Class II restorations in permanent tooth extending 1/3-1/2 B/L intercuspal width of tooth
Indirect resins allow more complete polymerization of resin and reduced shrinkage
29
Contraindications for composite
Young children at high caries risk
| Tooth cannot be isolated
30
What does beveling do in composite?
Removes the prismatic layer of enamel, which may not etch well
31
What is the increment of composite that can be placed at a time?
2-4mm
32
How do you achieve the best contact for back-to-back restorations?
Do one at a time
33
What is the typical polymerization shrinkage of most composites?
1-5.7%
| Newer composites are lower
34
Advantages of bulk fill composite
Increased depth of cure (4-5mm)
Decreased time to cure (20s)
Less technique sensitive
35
Disadvantages of bulk fill composite
Greater translucency, poorer esthetics
Extra equipment
Shrinkage/post op sensitivity
36
Etching
Overcomes smear layer, obstruction of dentin tubules
Liquid and gel produce similar results
No significant difference of resin bond strength etching for 20 or 60 seconds
37
Bonding Agent
Solutions of resin monomers with hydrophilic and hydrophobic groups
Rely on phosphate-calcium bond for retention
38
Hybrid Layer
Mechanical bond created when the smear layer is removed, monomers infiltrate into demineralized dentin, polymerize and interlock with dentin matrix
39
How does composite bond to dentin?
Micromechanical retention
| Little evidence supports chemical bond
40
Glass Ionomer Physical Properties
```
Chemical bonding to enamel and dentin
Thermal expansion similar to tooth
Less shrinkage than resin
Uptake and release of fluoride
Hydrophilic
```
41
What is the only dental material that has potential for true adhesion to tooth structure?
GI
42
3 Categories of GI
Luting
Restorative
Base/Liner
43
Composition of GI
Base: calcium or strontium alumino-fluoro-silicate glass powder
Acid: polyacrylic acid
44
How does GI bind to dentin?
Hydrogen bonds at tooth surface
| Free hydrophilic carboxyl groups form the bond
45
How does GI release fluoride?
Hardening reaction involves neutralization of acid by powdered glass base
Fluoride is released by reaction from calcium and aluminum ions binding to polyacrylic acid
Requires presence of water
46
How does GI result in tooth sensitivity?
If not sufficient water is present, GI takes water from dentin tubules
47
Is GI recommended for class II restorations in primary molars?
No
| Conventional GI is not recommended
48
RMGI
Conventional glass ionomer formulation with addition of resin monomers of acrylic acid and methacrylate like HEMA
49
Triple Hardening of RMGI
Initial curing of light-sensitive resin
Chemical resin cure
GI acid/base neutralization matures over time
50
Sandwich Technique
GI or RMGI is used to replace dentin, composite is overlaid as a bonded enamel replacement
Ionomer bonds adhesively to tooth, bonding agent bonds mechanically between ionomer and enamel
51
Advantages of Sandwich Technique
Decreased marginal leakage
Reduced sensitivity
Reduced shrinkage
Improves esthetics of GI/RMGI only
52
Indications for RMGI
```
May be considered for class I and II restorations in primary teeth
Class V permanent teeth
```
Insufficient evidence for long-term restorations in permanent teeth
53
RMGI compared to composite
RMGI has less wear resistance
RMGI has lower fracture strength
RMGI placed without occlusal dovetail is more likely to show adhesive failure
54
Compomer
Polyacid modified resin composite
72% strontium fluorosilicate glass and resin matrix to allow for release of fluoride
Does NOT recharge with fluoride like GIC
Not hydrophobic
No bond to tooth structure (must be used with adhesive)
55
Compomers for restorative material?
Not enough data to compare compomers to other restorative materials
Resins have better mechanical properties than compomers
56
Should you acid etch with compomer?
Not according to manufacturer instructions, but studies found better bond strength with enamel acid etch
57
Bioactive material compositions
56% filler
21% bioactive glass filler
Bioactive ionic resin matrix
Rubberized resin
58
Properties of bioactive materials
```
Some chemical bond to teeth
No Bis-GMA or BPA derivatives
Releases calcium phosphate and fluoride
Reportedly greater deflection to break than composite or RMGI
Light cure 20s, chemical cure 2 min
```
59
Technique for bioactive materials
```
Etch 10s
Use bonding agent in non-retentive prep
Dispense into preparation
Use up to 4mm
Allow to be in contact for 20-30s
Light cure
```
60
Does ACTIVA, composite, or RMGI have greater microleakage?
ACTIVA has greater microleakage than composite or RMGI
61
What type of steel is used in SSCs?
316 Stainless Steel
| Orthopedic surgery type
62
Composition of SSCs
65-73% iron
17-19% chromium
Some nickel
63
Indications for SSCs
```
After pulp therapy
Multisurface caries in high risk
Proximal box extending beyond line angle
Fractured teeth
Teeth with extensive wear
As abutment for space maintainer
Multisurface lesions when restoration needed more than 2 years or if patient is younger than 6
```
64
Contraindications for SSCs
Patients undergoing MRI of head and neck
Patients with nickel allergy
Teeth exfoliating in 6-12 months
65
Indications for permanent tooth SSC
Interim restoration
When finances do not allow lab-fabricated crown
Teeth with developmental defects
Permanent tooth requiring full coverage but partially erupted
66
Technique for permanent tooth SSC
1.5-2mm occlusal reduction
Restore original morphology with buildup before cementation
BW radiograph to verify fit
67
Comparison of SSCs versus amalgam and composite
SSCs have highest success rates
Amalgam failure 2-7x SSC
Cost per patient is lower when teeth restored with SSCs due to fewer replaced restorations
68
Reasons for failure of SSCs
Crown loss
| Perforation
69
Gingival health and SSCs
Crowns with poorly adapted margins show gingivitis
Extension of crown not associated with gingival health
Poor OH associated with unhealthy gingiva around SSCs
70
Primary tooth SSC technique
```
Occlusal reduction 1.5mm
Proximal reduction without ledges (feather edge)
Round line angles
Minimal buccal and lingual reduction
Crown seats 0.5-1mm subgingival
```
71
Cementing SSC
Bonded resin cement has greater tensile strength and retention with least microleakage - may have isolation problems
GI or RMGI is acceptable
Do NOT use polycarboxylate cement
72
Purpose of base/liner
Reduce marginal microleakage
| Prevent sensitivity
73
Calcium hydroxide formulation
Catalyst paste: Ca(OH)2, zinc oxide, zinc serate in ethylene toluene sulfonamide
Base paste: calcium tungstate, calcium phosphate and zinc oxide in glycol salicylate
74
Calcium Hydroxide Properties
Alkaline pH prevents bacterial invasion
Hydrolysis and microleakage
Should use less soluble high-strength base over calcium. hydroxide
75
Zinc Oxide Eugenol formulation
Powder: zinc oxide, rosin and zinc acetate
Liquid: eugenol
76
ZOE properties
Sedative effect for pulp
Low compressive effect
Eugenol is inhibitor for polymerizing resins
77
Hall Technique Success
Up to 98% successful
More successful than intracoronal restorations
No different than traditional SSC
78
Alternative Restorative Technique
Means of restoring and preventing cares in populations with little access to traditional dental care
Developing countries
79
Interim Therapeutic Restoration
May be used to restore, arrest or prevent progression of caries where traditional restoration is not possible or desirable
Fluoride releasing materials, no anesthetic, minimal tooth structure removal
Not great for interproximal restorations
80
Failure from ART/IRT?
Inadequate cavity preparation
| Loss of mechanical retention
81
Esthetic posterior SSCs
Major problem is chipping and loss of preveneered facings
More reduction than SSC, cannot be crimped/adapted as much
Moisture/heme control is less of an issue compared to zirconia
82
Why are class III restorations difficult in primary teeth?
Small clinical crowns
Large pulp chambers
Thin enamel
May need labial or lingual dovetail
83
Indications for full coverage for primary incisors
```
Multiple carious surfaces
Incisal edge involvement
Extensive cervical decay
Pulp therapy
Hypoplastic
Poor moisture or hemorrhage control
Large single-surface lesions
Discolored incisors that are esthetically unpleasing
```
84
Are zirconia or SSC more resistant to fractures?
SSC
| However all crowns exceed maximum bite force of children 6-8 years
85
Main reasons for zirconia failure?
Loss of crown
| Infection
86
Is gingival health better around SSC or zirconia?
Zirconia
87
Advantages of zirconia
High strength
Abrasion resistant
Biocompatible
Color-stable
88
Disadvantages of zirconia
Greater tooth reduction
More technique sensitive
Higher cost
Can cause abrasion of opposing teeth
89
Prosthetic replacement of primary incisors
Space maintenance typically not required for incisors
Ideal to allow 6-8 weeks following tooth loss before appliance fabrication but can be done immediate
Bands or SSCs on primary molars are abutment for anterior pontic teeth
90
Diastema closure
Orthodontist can help have optimal arrangement of teeth for closure
Partial diastema closure may be a good option
91
Microabrasion
Esthetic treatment of hypoplasia
Hydrochloric acid 6.6% in slurry of silicon carbide microparticles
Follow with fluoride treatment
92
Full coverage restorations of permanent teeth
Reduction of all ceramic materials are less than metal-ceramic (1.5mm vs 2mm)
Posts and cores do not strengthen teeth (only indicated with inadequate structure)
Veneers require 0.3-1mm tooth structure removal
93
Vital Bleaching
Hydrogen peroxide, carbamide peroxide or sodium perborate
Home bleaching: carbamide peroxide
Office: hydrogen peroxide, rubber dam, light
Carbamide peroxide is 1/3 what hydrogen peroxide is
-ex: 10% carbamide peroxide is 3.3% hydrogen peroxide
94
Side effects of vital bleaching
Sensitivity
Tissue irritation
Marginal leakage of restorations
95
Nonvital bleaching - walking bleach technique
Walking bleach technique
- open RCT, ensure no pulp remains
- clean with alcohol
- create cervical seal below CE
- sodium perborate mixed with water
- change after 3-7 days
96
Side effects of nonvital bleaching
Increased marginal leakage of existing restoration
External root resorption
Ankylosis
97
Issues with dental implants in pediatrics
Impact of growth on position of impact
| Effect of implant-supported prosthesis on growth and development
98
Implants in mandible
May be done in patients with ectodermal dysplasia
Mandible has less change, so implants can be done earlier
Posterior mandible implant placed too early may lead to lingual positioning of implant
99
Implants in maxilla
Can give rise to diastema
| Prosthesis of midline can inhibit growth
100
Pubertal growth spurts
Boys: 11-17 years
Girls: 9-15 years
Important to consider growth for implant placement
101
Dental lasers
Device that generates intense beam of coherent monochromatic light by stimulated emission of photons from excited atoms or molecules
102
Differences primary teeth from permanent
```
Enamel is thinner
Greater dentin thickness over occlusal fossa
Pulp horns are higher
Pronounced cervical ridges
Enamel rods slope occlusally
Marked cervical constriction
Longer, more slender roots
Roots flare out
```
103
Crowns of primary teeth
```
Shorter than permanent teeth
Wider MD
Narrower occlusal table
Cervical constriction
Broad, flat contacts
Prominent MB bulge
No developmental grooves/mamelons on incisors
Thinner enamel
Lighter in color
Dentin tubules increase in diameter with depth toward pulp
```
104
Pulp in primary teeth
Larger than permannet teeth
Pulp horns closer to outer surface
Great variation in size and location
Mesial pulp horn is higher
105
Roots of primary teeth
```
Anterior roots are narrower MD than BL
Molar roots are longer and more slender
Roots more flared
Roots branch directly from crown with no root trunk
Larger apical formina
Many accessory canals
```
106
Maxillary Central Primary Incisor Anatomy
MD crown width is greater than crown height
| Square Tooth
107
Maxillary Lateral Primary Incisor Anatomy
Longer than maxillary central
108
Maxillary Primary Canine Anatomy
Wider, more symmetrical than mandibular canine
| Cusp tip is offset to the distal
109
Maxillary 1st Primary Molar Anatomy
Greatest dimension is BL
| 4 cusps - 2 distal cusps are diminished
110
Maxillary 2nd Primary Molar Anatomy
Very similar to permanent counterpart
| Can include cusp of Carabelli
111
Mandibular Central Primary Incisor Anatomy
Narrowest tooth MD
| Straight incisal edge, very symmetrical
112
Mandibular Primary Lateral Incisor Anatomy
Wider and less symmetricalthan central
| Rounded incisal edge
113
Mandibular Primary Canine Anatomy
Narrower than maxillary
Cusp is to mesial
Long distal slope
114
Mandibular Primary 1st Molar Anatomy
Wider MD than BL
2 mesial cusps are larger than distal cusps
Prominent "S-curve" of gingival tissues
Broad contact between mesial of of molar and canine
115
Mandibular Primary 2nd Molar Anatomy
Similar to permanent counterpart
| Narrower BL and less pentagonal than permanent 1st molar
116
Objectives of Restorative Care
```
Restore damage caused by caries
Preserve remaining tissue
Prevent pain and infection
Retain function
Restore esthetics
Facilitate good hygiene
Maintain arch length
```
117
Sensitivity vs Specificity for caries diagnosis
Sensitivity: ability to determine caries when present
Specificity: ability to determine absence of caries when disease is not present
Visual, radiographic, laser fluorescence, fiber optic transillumination, electrical conductance, quantitative light-induced fluorescence have poor sensitivity and specificity
118
What is the best current method for caries detection?
Visual methods continue to be the standard for clinical assessment due to financial and practical reasons
119
Nonselective/Complete Caries Excavation
Carious dentin is completely removed at first visit
120
Stepwise caries excavation
Carious dentin is partly removed at 1st appointment with caries left over the pulp and temporary filling
Remaining carious dentin removed at 2nd appointment
Reduces pulp exposure compared to complete excavation
121
Partial/Incomplete Caries Excavation
Caries left over pulp with base and restoration placed in one visit
Reduces pulp exposures compared with complete excavation
More cost effective than stepwise excavation
122
OSHA requirements for materials
MSDS sheets need to be in a binder for any material that you have in your office
123
Epidemiology of pit-fissure caries
90% of caries in permanent teeth of children occurs in pits and fissures
2/3 occurs on occlusal surface alone
Primary teeth 44% occlusal caries
124
Is fluoride more or less effective on smooth surface compared to pits and fissures?
More effective on smooth surfaces
125
Primary, Secondary, Tertiary Prevention
Primary: intervention before evidence of disease (sealants)
Secondary: intervention after disease has begun, before symptoms (sealants)
Tertiary: intervention after disease is established (temporary sealant, PRR)
126
ADA Noncavitated/Initial Lesion Definition
Initial caries lesion development before cavitation occurs
Change in color, glossiness or surface structure as a result of demineralization before macroscopic break in tooth structure
Up to D1 lesion
Sealants can be placed on these lesions
127
Sealant success
Up to 76% reduction of incidence of occlusal caries
Risk of developing carious lesions in teeth with fully or partially lost sealants is no greater than teeth that have not been sealed
Sealed restorations superior to unsealed
128
Indications for Sealants
```
Caries-susceptible permanent molars
-history of caries in primary molars
-susceptible anatomy
-poor oral hygiene
Teeth that can be isolated
```
129
Resin Based Sealant Composition
Monomer: urethane dimethacrylate or bisphenol A-glycidyl methacrylate
Bis-GMA is product of bisphenol A and glyceryl methacrylate
130
Mechanism of adhesion of resin sealants
Mechanical
131
Wavelength of light for curing sealants
450-470nm
Camphorquinone/diketone-amine system
Minimal light output is 350
132
How do chemically cured sealants set?
By means of tertiary amine (activator) that is mixed with benzoil peroxide, producing free radicals that initiate polymerization
133
Compomer Sealants
Hydrophobic
Requires bonding agent
Fluoride release is low
Less retention than resin sealant
134
GI/RMGI Sealants
Suggested when isolation is difficult
| Mechanical and chemical retention
135
GI versus Resin Sealants
GI has 5x greater risk of loss
GI has 3x greater risk of loss compared to RMGI
No difference in caries development with GI or resin sealant, but resin based has better retention
136
Indications for Sealant
Pit and fissure caries are questionable or in enamel only
Caries-free pits and fissures with at risk morphology
Medical history of xerostomia
Patient is receiving routine preventive dental care
137
Contraindications for Sealant
```
Caries extends into dentin
Proximal caries or restoration involving pit and fissures
Inadequate isolation
Minimal or no caries risk
Pit and fissure morphology not at risk
Sporadic dental care
```
138
Reason for sealant failure
Most common from salivary contamination
139
Sealing over caries?
Acid-etch eliminates 75% of viable bacteria
Following sealant placement, dentinal lesions have been shown to be arrested
Retention of sealants over sound and carious tooth surfaces are similar
140
ADA Guidelines - Sealant Panel Recommendations
- Sealants effective in preventing and arresting pit-and-fissure caries in primary and permanent molars
- Sealants can minimize progression of non-cavitated occlusal carious lesions (initial lesions)
- Use of hydrophilic bonding layer enhances long-term retention
- Self-etching bonding agents provide less retention than total etch
- Routine mechanical preparation of enamel before etch is not recommended
- When possible, 4-handed technique should be used
- Use of explorers is not necessary for detection of early lesions
141
Is there a difference in sealant retention with air polishing versus conventional cleaning methods?
No
142
Rubber dam versus vacuum system isolation for sealants?
No difference
| Rubber dam better than cotton
143
Does topical fluoride interfere with bonding between sealant and enamel?
No
144
Should you use adhesive with sealant?
Yes
| Probably should cure it
145
BPA and Dental Materials
Dental materials contribute to very low level BPA exposure for up to 3 hours
Amount does not exceed FDA safe exposure limit
Limit by gargling with water, pumice on cotton ball, rubber prophy cup
146
PRR and CAR
PRR: Preventive Resin Restoration
CAR: Conservative Adhesive Restorations (reflects that other bonded materials like GI may be used)
Both involve removal of caries with sealant of adjacent pits/fissures
147
Resin Infiltration (ICON)
```
Can improve appearance of WSL
May reduce lesion progression
No preparation required
No margin of restoration
Not radiopaque
```
148
Components of resin infiltration
Icon dry: ethanol
Icon etch: 15% hydrochloric acid
Icon infiltrate: methacrylate based resin matrix, ignitors, adhesives
149
Indications for Resin Infiltration
Noncavitated E1-D1 lesions
WSL
Posterior and anterior use
