Restorative Flashcards
1
Q
What is the most important thing to consider when prescribing fluoride supplements?
A
The age of the patient and concentration of fluoride in the water
2
Q
____ are considered the best restorative materials in class IV cavity preparations
A
Composite resins
3
Q
In acute caries, the cavity floor is ___ in consistency
A
Soft and caseous
4
Q
Acute caries are ___ in color
A
Lighter (mostly light brown and grey)
5
Q
What is the optimal range of drinking water fluoridation as defined by the US CDC guidelines?
A
0.7-1.2ppm
6
Q
What are compound carious lesions?
A
Carious lesions found on two surfaces of the same tooth
Complex caries is found on MORE than 2 tooth surfaces
7
Q
Dentinal sclerosis occurring with aging is termed ___ . Dentinal sclerosis due to mild irritation is termed ___.
A
Physiologic dentinal sclerosis
Reactive dentinal sclerosis
8
Q
Xerostomia can cause…
A
Dental caries Oral candidiasis Oral dysesthesia Dry mucosa Dysphagia Fissured tongue associated with atrophy of filiform papillae Difficulty wearing dentures
9
Q
True or false… pilocarpine causes xerostomia
A
False. It is used to treat xerostomia
10
Q
Incipient interproximal caries are typically found where?
A
Just gingival to the contact
Incipient interproximal caries extend up to half the thickness of enamel and do not extend beyond enamel
Incipient caries do not necessarily require restoration unless the patient has a high caries risk index. Prescription of fluoride toothpaste or sealants are typically sufficient treatment for patients with low careis risk
11
Q
___ is the leading reason for the extraction of primary teeth
A
Untreated caries
12
Q
After dental plaque is formed, it adheres to the surface of the tooth through ___, which are…
A
Dextrans
Insoluble and stick and serve to increase the tenacity of the attachment fo dental plaque to the surface of the tooth
13
Q
Dextran is chemically and physically complex polymer, so breakdown is carried out by a variety of ___ and ___ found in ___
A
Endo- and exodextranases found in saliva
14
Q
Roughly __% of the dry weight of dental plaque is water-insoluble glucans.
A
20%
15
Q
____ is a gram +, facultative anaerobic, rod-shaped, filamentous, and is mostly associated with root surface caries
A
Actinomyces viscosus
16
Q
Which part of the tooth is most commonly misdiagnosed as caries on a radiograph?
A
CEJ
17
Q
As dentinal tubules approach the pulp there is an increase of what three things?
A
Density
Diameter
Permeability
18
Q
Why is glucose less cariogenic than fructose?
A
It is a monosaccharide not a disaccharide
19
Q
True or false… glycogen is cariogenic
A
False… because it is unable to be broken down into monosaccharides in the oral cavity
20
Q
Fluoride ions incorporated at the ___ stage of tooth development produces a tooth structure that is more resistant to careis
A
Calcification
21
Q
Fluoride ions can replace the ___ ions during the calcification stage of tooth development, which results in a structure that is more compact and resitant to caries
A
Hydroxyl
22
Q
The initial colonizing bacteria is collectively known as ___ plaque and predominantly consists of ___ microorganisms. The two main ones are __ and ___
A
Supragingival
Gram + facultative
Actinomyces viscosus
Streptococcus sanguinis
23
Q
What is the best treatment plan to control rampant caries?
A
Remove caries, place glass ionomer restorations, then complete the treatment plan after the vitality of the teeth has been established.
The placing of glass ionomer restorations allows the affected dentin to be remineralized
24
Q
Transillumination utilizes light scattering and photon absorption of enamel and dentin to detect caries. Enamel lesions present ___. Dentin lesions present___.
A
Gray shadows
Bluish or orange-brown shadows
25
An increase in saliva ___ would increase a patient’s caries risk.
Viscosity. Its ability to flow is altered resulting in its diminished function in the oral cavity
26
What should the dentist considered primarily when restoring the incisal edge or enameloplasty for a patient with slight chipping of the incisal edge of maxillary central incisors?
Amount of translucent enamel present
The thickness of enamel in the incisal surface is greater than that of the facial surface
27
In what 3 ways does fluoride prevent tooth decay?
Decreases enamel solubility
Interferes with bacterial metabolic activity
Remineralizes tooth structure
28
The ___ surface of primary teeth is most susceptible to staining because...
Cervical
The cervical bulges can trap debris underneath
Cervical portions are mor constricted in primary teeth thus making plaque, caries, and stain formation easier
Children are incapable of brushing the cervical areas properly due to limited dexterity.
29
What is the best way to treat superficial decalcification/staining seen in deep fissures of molars?
Enameloplasty limited to the superficial depth of the decalcified enamel. This will avoid unnecessary tooth preparation required for a full restoration and makes the grooves more cleansible.
30
What are 4 organic components of oral bacterial plaque? What are 5 inorganic components?
Polysaccharides, glycoproteins, proteins, lipids
Calcium, sodium, potassium, phosphorus, fluoride
31
What is the diagnosis for a tooth with a cavity floor that is hard and leathery with a very dark appearance? These lesions occurs as a result of ___ involvements and affect a ___ number of teeth and are __ in size.
Chronic caries
Long-standing caries
Fewer
Smaller
32
True or false... pulp prognosis is very good in cases of chronic caries
True. Because tertiary dentin formation occurs in the cases of chronic caries
33
True or false.. acute and aggressive caries is a rapidly occurring disease process that typically involves less teeth than chronic caries
False... it involves a greater number of teeth
34
True or false... the pulp is responsible in forming cementum
True
35
What mechanism in which mercury enters the body is considered to induce the highest toxicity?
Inhalation
80% of elemental and inorganic mercury is absorbed in the lungs
36
The generally accepted threshold limit for exposure to mercury vapor for a 40 hr work week is ___ micrograms per cubic meter
50
37
What are some of the main mercury hazards in the dental operatory?
Mercury vapors released from stored materials
Small losses from capsules during trituration
Spillage during manipulation for restorations
Vapor exposures during removal, placement, finishing, and polishing of amalgam
Cotton roll contamination
Collection of debris via vacuum suction in the plumbing system
Collection of remnants in a jar for recycling
Mercury trapped in carpet fibers or floor tiles
38
Dentin has an average thickness of about ___mm. A minimum remaining dentin thickness of __mm can help prevent pulpal damage
3
2
39
With a remaining dentin thickness of __mm, pulpal reaction to increased bacterial load is observed. With a remaining dentin thickness of ___mm, loss of odontoblasts is observed.
0. 75mm
| 0. 25mm
40
What is the most accepted treatment for mottled enamel?
Microabrasion with hydrochloric acid (HCl)/pumice
Mottled enamel is a condition in which a combination of small white, brown, and yellow spots are seen all over the surfaces of the teeth
Microabrasion removes a thin layer of stained enamel with the use of pumice and hydrochloric acid. HCl whitens the stains in the tooth surface and has an effect that lasts for a few days after its application
41
The primary objective of the clinician in treatment planning is to...
Respect the patient’s rights to be treated in a way that puts their rights to autonomy, beneficence, justice, nonmaleficence, and veracity above all else.
42
What esthetic properties does dentin provide?
Chroma
Opaqueness
Fluorescence to above-lying dental enamel
43
The distance light is able to travel into tooth structure before being reflected back outward is termed ___. What is penetrance?
Degree of translucency
Penetrance is the degree of the ability of light to pass through
44
What can happen if a preparation is done with the high-speed handpiece used with the water off but still cooling the tooth with air?
Hypersensitivity in the prepared tooth - could lead to irreversible pulpitis
Irritation of the pulp from being too dry
The odontoblasts to be forced into the dentinal tubules, causing damage
45
True or false.. zinc-oxide eugenol cement provides an excellent marginal seal.
True
46
Erosion of teeth is most commonly caused by __ in males and most commonly caused by ___ in females.
Ingestion of acidic beverages
Bulimia
47
Acute reversible pulpitis is a transient condition of the pulp in which unusual sensitivity is experienced due to __, ___, ___, ___, ___, or ___
Thermal shock - due to preparation or polishing process
Trauma - induced by a blow to the tooth or improper occlusal relationship
Desiccation - typically occurs when the tooth is prepared without the utilization of a high-speed handpiece without a water jet
Placement of an amalgam restoration in contact with a gold restoration - the tooth will experience galvanic shock from having two different metallic restorations contact within the oral cavity
Chemical stimulus - sweets are easily fermented by bacteria to form acid that triggers sensitivity
Caries extension - continuous bacterial attack on the tooth surface causes pain and sensitivity to tooth, but such pain is lost after stimulus is removed
48
What is the correct order of listing the tolerance of occlusal forces from greatest to least?
Molars
Canines
Premolars
Incisors
49
The normal physiologic contact wear of teeth is ___ micrometers per year
29
50
Removal of dentinal smear layer [increases/decreases] bond strength, [increases/decreases] dentin wetness, and makes microleakage [more/less] significant because barrier of bacteria to pulp is removed. It [increases/decreases] fluid flow onto the the exposed dentin surface.
Increases
Increases
More
Increases
51
What are two strategies used to overcome the low attachment strengths of smear layer?
Removal of the smear layer prior to bonding by acid etching
Or
Use of bonding agents that can penetrate the smear layer and incorporate it into the bonding layer
52
Arrested caries may appear [darker/lighter] due to...
Darker
Due to staining from recent demineralization and do not necessarily require restoration
53
What are 4 favorable properties of a good sealant?
Light cured polymerization (to provide ample working time)
Fluoride release
Opaque/tinted (to differentiate from tooth structure)
Filled composite resin
54
Dentin-bonding mechanisms largely rely on the properties of ___ agents like ___, which penetrate into the inherently moist dentin surfaces and are able to copolymerize with composite resins.
Difunctional coupling
Silanes
55
The majority of bond strength is obtained from ....
The interdiffusion zone formed by the bonding agent and the dentin is called the ___
Penetration and adaptation of the bonding agent to the demineralized intertubular dentin and exposed collagen fibers
Hybrid layer
56
What accounts for the primary retention of fissure sealants?
Micro-mechanical retention
Deep pits and fissure are more retentive than shallow pits and fissures
57
The restorative material with the highest potential for marginal leakage due to high thermal elasticity properties is ___
Unfilled resins
Higher coefficient of thermal expansion means that the resin expands and contracts faster than the tooth, resulting in gaps that make teeth sensitive to changes in temperature and increase marginal leakage
58
True or false... silicate cement restorations are not good for restoring teeth with proximal contacts
True
59
Silicate cement is ___ and prone to surface ___ on the margins because ___ in silicate cements are easily dislodged from the restorative filling. Because they wear easily, they are unsuitable for restoring ___ and ___.
Brittle
Chipping/crazing
Glass particles
Proximal contacts and stress bearing areas
60
G.V Black’s steps in cavity preparation consist of...
1) establish outline form
2) obtain resistance form
3) obtain retention form
4) obtain convenience form
61
What is a class 6 carious lesion?
Cusp tip
62
True or false... the only way to truly determine the status of the pulp is through histological analysis and not with the clinical signs and symptoms the tooth elicits
True
63
The filler particles within resin composite are coated with ___ to promote adhesion to the matrix. Dental resin composites are composed of a resin matrix that contains ___ and ___ as well as ___, ___, ___, ___ and a ____.
Silanes
Monomers
Cross linking monomers
Free radical initiator
Inhibitor
Coloring agents
Filler materials such as barium, glass, silica, apatite
Silane coupling agent
64
The coupling agent in resins function to___
Enhance the bonding between the filler particles and resin matrix
65
Spherical alloys are [more/less] sensitive to variation in condensation pressure. They demonstrate [higher/lower] mercury-to-alloy ratio. They demonstrate a [longer/shorter] working time and [faster/slower] set comparatively. They demonstrate [better/poorer] adaptation to cavity walls. They typically create [better/poorer] interproximal contact in class II restorations.
Less
Lower
Shorter
Faster
Poorer
Poorer
66
True or false... admired alloys typically yield better interproximal contacts for class II restorations. Amalgam of spherical powder is very plastic and cannot rely on pressure of condensation to establish proximal contour.
True
67
What are some advantages of composite resins over amalgam for posterior restorations? What is a disadvantage?
Esthetics
Conservation of tooth structure
Low thermal conductivity
Disadvantage = low fracture toughness. Not as good marginal seal
68
Replacement of a defective amalgam with a cast gold restoration can achieve ___ and ___
Provide a better marginal seal
Provide more ideal contours
69
What is the primary reason for administration of prednisolone during an operative procedure?
It decreases the likelihood of pulpal inflammation
Prednisolone can decrease pain stimuli by reducing the production of prostaglandins responsible for the mediation of pain and inflammation
Prednisolone is an anti-inflammatory steroid drug that functions as an effective inhibitor of phospholipase A2, which is responsible for promoting inflammation.
It has the ability to down-regulate some pro-inflammatory cytokines and reduce the pulpal inflammation during operative procedures
70
___ is considered to be the only dental restorative material that improves its marginal sealing with age due to ___
Amalgam
Corrosion, which seals the micro-gap between the tooth and restorative material with age.
71
For an ideal class 5 restoration on a mandibular premolar, what is the most important factor when choosing a restorative material?
Reaction of the gingival tissue
Esthetics are less of an issue in this case because it is less visible than an mandibular anterior tooth
72
____ is typically the most indicated restorative material for class 5 posterior restorations because they...
Glass ionomer
Bond to root surface
Release fluoride to help protect the surrounding root structure
Are easily contoured
Are easily smoothed
73
The coronal dentin in primary teeth is ___ as thick as permanent teeth because primary teeth have pronounced ___ which cause less dentin coverage. Permanent teeth are larger in size and have smaller pulp spaces in relation to their crown size. Dentin formation occurs throughout life thus increasing the bulk of dentin in permanent teeth
50%
Pulp horns
74
When restoration a MO or DO, an onlay is indicated if...
Cuspal integrity is in question
Onlays reinforce fractured, weakened or unsupported tooth structure
Weakened cusps are reinforced by reducing unsupported structure and replacing it with a durable material capable of bearing heavy occlusal forces
75
What is the most significant disadvantage of glass ionomer cements?
Moisture sensitivity during initial curing
Water is essential in the setting reaction of glass ionmer cement as it sets through an acid-base reaction
Water loss and moisture contamination must be prevented in order to obtain satisfactory physical properties.
Desiccation prevents formation of the polycarboxylate matrix, resulting in a rough, chalky surface and decreased surface hardness
During the latter part in the reaction, water is essential in hydrating the crosslink of the polymer matrix to strengthen the cement
76
Tooth whitening procedures are contraindicated in patients with ___ and or ___
Amelogenesis imperfecta because they usually have improperly formed enamel and may demonstrate suboptimal outcomes
Old and stained composite restorations. They can never be whitened through bleaching. Whitening these teeth will make the stained composite restorations more noticeable
77
What composite resin constituent provides the most radiopacity?
Barium
78
The ADA states that resin based composites are endorsed in which 3 conditions?
Small-moderate sized restorations
Conservative tooth preparations
Areas where esthetics is important
79
Posterior composite resins are contraindicated in what three situations?
Large sized cavity preparations
Areas where isolation is difficult to achieve
Exposed root surfaces where it is difficult to achieve optimum bonding
80
Define fluorescence
When light is absorbed by a substance and emitted back in a longer wavelength
81
What mechanical property measures the materials ability to resist the propagation of a crack?
Fracture toughness
82
Define elasticity
The tendency of solid materials to return to their original shape after being deformed
83
Define flexural strength
The materials ability to resist deformation under load
84
Define hardness
A measure of how resistant a solid matter is to various kinds of permanent shape change when a force is applied
85
Microfilled composite [allow/inhibit] restorations to bend with tooth flexure, better protecting the bonding interface, thus they may perform better in certain class restorations than a more rigid hypbrid composit
Allow
86
What are four disadvantage to microfilled composites?
Increased thermal expansion
Decreased tensile strength
Increased water absorption
Increased polymerization shrinkage
87
What is the purpose of amphipathic primer in composite resins?
Allow the hydrophobic unfilled resin (adhesive) to penetrate the collagen network exposed after etching with acid
88
___ helps to make bond between the resin on one end and the filler on the other end, acting as a bi-functional coupling agent
Silane
89
True or false...
Mercury demonstrates a higher surface tension than water.
Mercury is the only metal that remains in a liquid state at room temperature
Under ordinary conditions, mercury cannot combine with nickel, chromium, molybdenum, cobalt, and iron to form amalgam
All are true
90
Mercury combines with ___ to form dental amalgam
Silver-copper-tin alloy
91
In ___ amalgam, mercury is liberated via corrosion and reacts with unreacted gamma phase to produce ___ and ___ phases. ___decreases the strength of amalgam. To avoid this decrease in strength, amalgams must be condensed to bring excess __ to the surface. This excess ___ is then removed at teh end of the placement of the restoration.
Low copper
Gamma 1 and gamma 2
Gamma 2 phase
Mercury
Mercury
92
In amalgams, less mercury leads to less ___ leads to less ___ which leads to ___
Corrosion
Potential gamma 2 phase
Increased strength of amalgam
93
In regards to amalgam restorations, a FL width of no more than ___mm and a depth are ___ are considered ideal. As an amalgam restoration becomes wider faciolingually, what are two drawbacks?
1-1.5mm
1.5-2mm
The tooth is more subject to fracture
The integrity of the restoration is less likely to be maintained
94
In a patient with cusps undermined by decay and heavy occlusal forces, which of the following is the restorative material of choice?
Cast gold
It can be easily finished, polished, burnished, and adapted to tooth structure to decrease recurrent caries risk.
Cast gold has the highest corrosion resistance of any restorative material
95
Which material demonstrates the highest rate of fluoride release, but also the least resistance to wear?
Glass ionomer cement
They are not recommended as restorative materials in high-stress bearing areas, however they may be used in class III and class V areas where stress are low (chemically bond to root surface and have high flexural strength)
These are mostly indicated as liners under stronger restorative materials
96
What is the primary advantage of placing a microfilled resin composite?
They are highly polishable which results in a restoration surface hat is less receptive to plaque or extrinsic staining
97
What tooth most commonly has the dental anomaly “dens in dente”?
Maxillary lateral incisor
98
Dentin is composed of ___% inorganic material (mostly ___) and ___% organic material (mostly ___)
70%
Hydroxyapatite
30%
Collagen
99
Dentin formation begins immediately [before/after] the enamel formation
Before
100
What material demonstrates the greatest coefficient of thermal expansion? It’s coefficient of thermal expansion is approximately ___ times that of the tooth structure.
Resin composites
Three
101
True or false... water absorption is greater in composites with smaller particles than in composites with larger particles
False.
Materials with higher filler contents exhibit lower water absorption values than material with lower filler content (quantity). Materials with smaller particle sizes have higher filler content, and those are more able to prevent the absorption of water than materials with larger particle sizes.
102
True or false.. the release of unbound monomers or additives is hypothesized to be the cause of the cytotoxicity observed in in-vitro studies of resin-based composites
True
103
Retentive features for class 5 allow restorations are typically placed on which surfaces?
Incisal/occlusal and gingival walls
Placement of undercuts should be confined within the dentin layer to prevent undermining of enamel.
Retention for class 5 restorations can be improved by lengthening the walls and making parallel opposing walls
104
Amalgam has a weak ___ strength and requires a ___ cavosurface margin and an adequate thickness for strength and durability. Cast gold preparations on the other hand require a __ to...
Edge
90 degree
Bevel to remove unsupported enamel rods and render a smooth-flowing form of cavity preparation. The bevel on the margins allows for better marginal adaptation through burnishing
105
True or false... internal angles in amalgam preparations should be acute
False.. they should be rounded
106
The ___ pulp horn of the mandibular first premolar is most susceptible to mechanical exposure during a class II amalgam prep. What should be done to counter this?
Buccal
The pulpal floor along the buccal cusp should be higher than the lingual to avoid encroaching on its prominent buccal horn
107
What is the smear layer and what is it composed of?
```
When the tooth surface is altered by rotary or manual instrumentation during cavity preparation, the cutting debris is smeared over the enamel and dentin surfaces, forming a smear layer. It contains:
Calcified debris
Shattered and crushed hydroxyapatite
Fragmented and denatured collagen
Bacteria
Saliva
Dentinal chips
```
108
What is the major difference between a class V preparation for an amalgam and a composite restoration?
Angulation of the enamel cavosurface margins
Amalgam must always have a 90degree cavosurface margin. The cavosurface margin preparation for class 5 composite however requires a 45degree bevel to provide additional surface for adhesion as well as to create an esthetically blended junction between the tooth and the composite material
109
According to GV Black, the outline form of a cavity preparation is the shape of the cavity preparation ____
Along the cavosurface margin
110
When prepping a tooth for a cast gold restoration, the tooth structure that is weakened by the preparation and subjected to masticatory forces must be ___
Reduced and protected by the restoration
Weak tooth structure must be reduced or removed. Undermined cusps and unsupported tooth structure are prone to fracture, so capping of cusps may be necessary to protect the tooth and provide strength.
111
What are some reasons to place bevels into enamel?
To enhance esthetics if the margin is to be in a visible location
To remove fragile enamel
To smooth the cavorestorative margins
Minimize the line of demarcation at the tooth-restoration interface
112
What is the first step in cavity preparation according to GV Black?
Establish outline form based on location and extent of carious lesion
113
What is the primary reason to diverge the mesial and distal walls occlusally in a class I amalgam cavity prep?
To prevent the undermining of the tooth structure of the marginal ridges
114
In a class III prep, a __degree cavosurface bevel serves what purpose?
45degree
Exposes more surface area of enamel rods that can be etched and bonded to retain and seal composite restorations
Note that no bevels should be placed on occlusal surfaces however.
115
___ pins are the most retentive, but their placement also creates stresses and cracks in the dentin. ___ pins are the least retentive but they put the least stress on dentin.
Threaded
Cemented
116
Why is it important to burnish amalgam after condensation and before carving?
It produces denser amalgam at the margins of restorations
Finalizes condensation
Removes excess mercury rich amalgam
Initiates carving process
117
Cast gold restorations are indicated to replace aging amalgams to ___
Achieve more ideal anatomy
118
True or false... spherical alloys contain more mercury than admired alloys
False
119
____ alloys are recommended for areas requiring development of proximal contacts
Admixed
120
___ are believed to be the major contributors to retention to enamel in regards to adhesives. The extend up to ___ deep.
Microtags
20 micrometers
121
Flowable resin composite demonstrates ___ times greater polymerization shrinkage than hybrid composite. They [are/are not] as radiopaque as enamel.
Three
Are not
122
What is the “snow plow” technique when it comes to class 2 composites?
A small uncured increment of flowable composite is placed on the gingival portion of the box then conventional composite is placed over it. The conventional composite is condensed to displace most of the flowable composite out of the cavity preparation and the rest of it flows into deeper portions where conventional composite cannot reach
123
True or false... incremental filling results in decreased post-operative sensitivity
True becuase incremental placement decreases the polymerization shrinkage and increases the percentage of curing
124
What is the acid and the base used in the reaction of glass ionomer bonding to tooth structure?
Acid: polyalkenoic acid
Base: Aluminosilicate glass
125
What is the function of a primer in the bonding process?
Infiltrate and remove water from animal prisms, dentinal tubules, and exposed collagen network
Form hybrid layer because it is made of solvents and bi-functional /ampiphilic penetrating monomers
126
How is the hybrid layer formed?
Etching removes the smear layer and hydroxyapatite within the intertubular dentin, in addition to exposing the collagen fibers
Primers penetrate the collagen network and allow the adhesive resins to form microtags within the intertubular dentin
127
Why is calcium hydroxide recommended for vital pulp capping procedures?
It is the most biocompatible material that has been proven to help induce dentin bridge formation
128
What are 4 advantages of indirect resin restorations over direct resin restorations?
Improved proximal contacts
Decreased marginal leakage
Increased strength
Decreased post-operative sensitivity
129
What are the primary disadvantages of indirect resin restorations?
Time
The patient doesn’t leave the office with the definitive restoration
130
____ is used as an initiator in self-cure or auto-curing composite resins.
___ is an initiatory and ___ are activators for light-activated composite resins
Visible light cure composites need a wavelength approximately ___nm to initiate the polymerization reaction
Benzoyl peroxide
Camphorquinone
Tertiary amines
468
131
Why is overfilling of amalgam in proximal restorations necessary?
Proper carving of the amalgam restoration can be achieved
Allows burnishing and achieving the contact point
Ease in the restoration of tooth morphology
132
true or false... composite resins chemically bond to dentin
False
133
True or false... glass ionomer cements chemically bond to tooth structure
True
134
If the remaining dentin thickness is greater than __mm glass ionomer cement can be used as cavity liner but for a remaining thickness of ___ or less, calcium hydroxide should be used, then glass ionomer should be placed overtop.
1. 5mm
| 0. 5mm
135
Alloys with higher copper content demonstrate [higher/lower] creep values because...
Lower
Because they exhibit little or no gamma 2 phase
136
Define creep in regards to amalgam
The time-dependent plastic permanent deformation of amalgam under static or dynamic loading
Creep causing protrusion of amalgam out of the cavity. The protruded edges are unsupported and weak and are further weakened y corrosion leading to fracture, ditching, and microleakage
137
The ____ phase is primarily responsible for higher creep values
Gamma 2
138
What is considered the most toxic form of mercury?
Organic
Mercury can form organic compounds such as methyl mercury. Organic mercury compounds can be readily absorbed by many organisms and concentrated as they pass up the food chain. Organically bound mercury in food is the primary source of mercury exposure in most people.
139
___ of mercury is less effective from the human body compared to its ___. Organic mercury has a tendency to concentrate in __, a___, and __ after being absorbed
Excretion
Absorption
Liver
Kidney
Brain
140
Mercury toxicity can result in ___, ___, ___ and ___. When inhaled in toxic quantities it can cause damage to the ___.
Bronchitis
Pneumonia
Kidney disease
Allergic reactions
CNS
141
Admixed amalgam alloy consists of __ and __ particles
Spherical
Lathe-cut
142
Admixed alloys have the “body” of ___ alloys when condensing; are easily condensed with good adaptation but are more easily worked with like ___ alloys.
Lathe-cut
Spherical
143
___ alloys can withstand forces of condensation better than ___ alloys which is why these alloys are preferred for proiximal amalgam restorations. __ alloys demonstrate higher levels of creep and corrosion compared to __ alloys.
Admixed
Spherical
Admixed
Spherical
144
Why is zinc added to low-copper amalgams?
Enhances its mechanical properties
Reduces delayed expansion where contaminated with moisture
Reduces marginal fracture rates
145
If a low-copper, zinc-containing alloy is contaminated with moisture, it will result in ___, ___, and ___
Surface blistering
Internal corrosion
Delayed expansion of up to 4% by Columba beginning 3-5 days after the contamination and continuing for up to 6 months, which can lead to creep and a reduction in strength of up to 24%
146
Which phase of amalgam is considered the weakest and has the least resistance to corrosion?
Gamma-2
147
Which phase of amalgam has the highest strength and corrosion resistance?
Gamma 1
148
___ is the amalgam phase which is considered unreacted during the chemical reaction between amalgam alloy and mercury
Gamma
149
How does acid-etching improve retention of composite restorations?
It increases the mechanical retention (not chemical)
It removes surface debris from the cavity preparation
Acid etching provides surface roughness to provide mechanical retention without too much loss of healthy tooth structure during cavity prepartion.
Microporosities created by acid etching allows even small cavity preparations to have retention despite insufficient retention form
150
What material is used as the base material for the bonded-base (open sandwich) technique?
Glass ionomer
151
Describe the open sandwich technique
A restorative GI or RMGI is used in the portion of the restoration near the gingival margin, because these materials are moisture tolerant
Recommended in composite restorations with margins in thin enamel near the CEJ or on cementum or dentin
Composite resins are placed over the GI portion without impeding the contact of GI with oral cavity
152
True or false... polishing of amalgam significantly increases the longevity of the restoration
False
153
When carving a freshly condensed amalgam, the amalgam begins to chip and flake away. Why would this happen?
The amalgam was condensed after its working time had elapsed
Overcondensation of amalgam alloy will result in chipping away of the filling material during carving
Prolonged condensation pressure will result in decrease strength of the amalgam restoration
154
Amalgam alloys typically take roughly ___ to set complexity, so undue pressure or disturbance during this time will result in the breakage of the restoration
24 hours
155
What is the optimal absorption energy for the activation of camphorquinone?
400-499nm (optimum = 465)
156
What is the first step in the delivery of a cast gold inlay?
Adjust contacts (CIMEO)
157
True or false... gold can be burnished against the margins of the preparation to make it more adapted and tightly fit for a good marginal seal
True
158
What induces sealants to polymerize?
The formation of free radicals
159
What are the steps of an indirect pulp cap?
Infected dentin is completely removed
Affected dentin close to the pulp is left due to the possibility of pulp exposure
Calcium hydroxide, followed by glass ionomer is placed over the affected dentin
Final restoration is placed
160
What are three factors that can affect photopolymerization?
Time of curing light application
Distance of curing light tip from surface of restoration
Irradiance and wavelength of the photopolymerizing source
161
What are 4 advantages of amalgam restorations over composite?
Less time-consuming to place
Lower cost
Less technique sensitive
Less likely to remove additional tooth structure when removing an amalgam restoration due to its color
162
How is composite bonded to adhesive resin?
Chemically bonded through polymerization through MMA bonds
163
what is a likely reason why an amalgam restoration would have an open gingival margin?
The clinician loaded too much amalgam into the prep before properly condensing it into proximal box
164
Which type of amalgam requires strong lateral force application to condense the amalgam?
Spherical
165
Composites in posterior teeth are indicated if what three criteria are met?
BL width of preparation is <1/3 inter-cuspal distance
Gingival margin of preparation is on intact enamel
Esthetics are important
166
What is the best conditioner to clean the tooth’s surface when applying glass ionomer adhesives?
Polyalkenoic acid (PAA).
PAA is used for GIs because it is a weaker acid that does NOT penetrate into the dentin as much as phosphoric acid. This is because the glass ionomers have a much higher molecular weight polymer that cannot penetrate into the smaller tubules created further gingivally by the phosphoric acid
Ethanol is a solvent primer used to remove excess water after rinsing acid
167
What is the maximum amount of resin composite that can be properly cured per layer?
2mm
168
What is the purpose of trituration of amalgam?
Remove oxide layers from the alloy particles, to coat each alloy particle with mercury, and to provide a homogenous mass for condensation
169
True or false.. if amalgam was properly triturated it should be dry and crumbly and should stick to the capsule walls
False
170
____ are dentinal sealer typically used in amalgam preps only
Super seal
171
Distal slot preparations are indicated in what 5 situations?
Proximal root caries in patients with gingival recession
Teeth with distal decay and no adjacent tooth positioned distally
Teeth with distal decay extending up to the DEJ
Small proximal caries that DOES NOT include or undermine the occlusal surface
Proximal caries in a tooth with attrition
172
When using matrix bands for posterior proximal amalgam restorations, the band should be trimmed to which dimension?
At least 1mm higher than the adjacent marginal ridge
173
What can happen if you place the matrix for an amalgam restoration too high?
Access and visibility problems
Difficult instrumentation
Difficult placement of materials
174
What is the best method to remove carious dentin near the pulp in a class 2 preparation?
A very slow rotating large bur - this will prevent accidental pulp exposures during caries excavation.
175
Spoon excavators are used to remove ___ dentin. They can leave ___ in the cavity preparation if __ is not used. A slow speed handpiece with a large bur will remove the affected dentin that a spoon excavator typically cannot.
Very soft, carious
Affected
Firm force
176
It is advised to carry out finishing and polishing of amalgam restorations at least ___ AFTER the placement of amalgam to allow complete setting to occur.
24 hours
177
What instruments can be used to polish amalgam restorations?
Sof-lex disks
Abrasive-impregnated rubber points
Prophylaxis cup with tin oxide
178
what are the purposes of placing a bevel on preparations for composite restorations?
To expose the ends of enamel rods instead of the sides
To improve the seal of the enamel-resin margin
To increase the surface area of enamel for etching
Eliminate the line between filling and tooth
179
___ bevels are placed on the facial side of a class IV preparation. ___ bevels are typically found around the margins of a class V restoration.
Esthetic
Retentive
180
What are three indications of composite restorations?
Small and moderate-sized restorations
Conservative tooth preparations
Areas where esthetics is important
181
Dental burs are typically made of what two different types of material?
Steel carbide - dull more quickly but are less prone to breaking.
Tungsten carbide (most) (they are best operated under high speeds with light pressure.
182
When placing a light-cured composite in a deep cavity preparation, the composite should be placed in increments no greater than ___
2mm
183
The __ of the gingival marginal trimmer corresponds to the nib of the ___
Blade
Condenser
184
In non-cuttin instruments the blade is replaced by a __ or __. The working ends or __ of condensers may be of any shape, but they are usually round with flat ends.
Nib or a point
Nibs
185
Adjacent proximal cavities are best restored in one appointment because... (list 5 things)
The cavity prep can be made more conservatively, preserving more healthy tooth structure.
There will be adequate access and visibility, enabling the dentist to work more efficiently/effectively
The restorations can be placed easier due to adequate space to finish the proximal margins of the restorations properly
Placing the restorations at the same time will decrease the wasted materials, for instance, adhesive, that must be dispensed
Placing the restorations at the same time DOES NOT increase the chance of having proximal contacts
186
The enamel rods of primary teeth are directed ___, making the gingival bevel [necessary/unnecessary]
Occlusally
Unnecessary
187
Dentinal plugs are composed of the __ of the ___. It is removed by ___
Debris from the smear layer
Acid-etching
188
True or false.. over-mixing admixed amalgam alloy causes a decrease in the overal strength
False
189
What are the effects of over-mixing admixed alloy? (3 things)
Decreases working time
Increases contraction
Increases creep
190
The optimal fluoride levels in water is __ to ___ mg/L
0.7 - 1.2
191
Why are optimal fluoride levels lower for warmer climates?
People tend to drink more water
192
___ is the minimum number of flutes needed on a carbide bur for it to be considered a finishing bur.
12
193
Conventional glass ionomers contain basic ___ glass and water ___. Conventional glass ionomer cements undergo a chemical self-setting ___ reaction created by mixing an ion-leachable ___ glass powder with an aqueous ___ acid
Ion-leachable
Soluble polyacids
Acid base
Fluoroalminosilicate
Polycarboxylate
194
In a class 5 restoration, where should the rubber dam be punched?
1mm facial to the disgraced tooth
195
What does DMFT stand for?
Decayed
Missing
Filled
Teeth
196
Filler particles provide strength to composite resins and help to improve what physical properties?
Reduces the coefficient of thermal expansion
Reduces polymerization shrinkage of the composite
Makes the material harder, denser, and more resistant to wear
Causes reinforcement of the resin matrix
Decreases polymerization shrinkage
Improves workability
Decreases water sorption
Increases radiopacity
197
The normal range of composite curing light wave length is approximately ___
470 nm
198
How thick should the first increment be for a class 2 restoration?
1mm
199
What are two advantages of the snowplow technique with class 2 composite restorations?
Decreased voids in the restoration
Decreased gingival marginal leakage
