Term Test 1 Flashcards
(137 cards)
1
Q
When were synthetic resins introduced?
A
1932
2
Q
When were cements introduced?
A
1855
3
Q
Know the classification of dental materials.
A
- Preventive
- Therapeutic
- Restorative
4
Q
When was fluoride first mentioned?
A
1874
5
Q
What year was fluorosis first noted?
A
1901
6
Q
Compressive force:
A
force applied to compress or squeeze object; crushing biting forces; posterior teeth are ideally suited for this type of force.
7
Q
Tensile force:
A
force applied to an object in opposite directions to pull object apart; biting forces used to stretch a material; imagine chewing a caramel.
8
Q
Shearing force:
A
force applied when two surfaces slide against each other in opposite directions. This occurs when max and mand incisors are used for cutting, and when anterior teeth are used to bite into food, mand teeth slide forward or to the side, and max teeth in the opposite direction to shear it off.
9
Q
Torsion or Torque:
A
twisting force that is a combination of tensile and compressive forces. This force is more descriptive of normal mastication.
10
Q
Solubility:
A
Susceptible to being dissolved.
11
Q
Water sorption:
A
The ability to absorb moisture.
12
Q
Corrosion:
A
Deterioration of a metal caused by a chemical attack or electrochemical reaction with dissimilar metals in the presence of a solution containing electrolytes (such as saliva).
13
Q
Tarnish:
A
Discoloration that results from oxidation of a thin layer of metal at its surface. It is not as destructive as corrosion.
14
Q
Dimensional change:
A
a change in the size of matter (expansion of dental materials due to heat or contraction due to cold temperature).
15
Q
Coefficient of thermal expansion (CTE):
A
the measurement of change of volume or length in relationship to change in temperature.
16
Q
Percolation:
A
movement of fluid within the microscopic gap of the restoration margin as a result of differences in the expansion and contraction rates of the tooth and the restoration with temperature changes associated with ingestion of cold or hot liquids or foods.
17
Q
Thermal conductivity:
A
The rate in which heat flows through a material.
18
Q
Insulator:
A
materials that have a low thermal conductivity.
19
Q
Retention:
A
A materials ability to maintain its position without displacement under stress.
20
Q
Adhesion:
A
The act of sticking two things together. Described as bonding or cementing in dentistry.
21
Q
Bonding:
A
to connect or fasten; to bind.
22
Q
Wetting:
A
The ability of a liquid to wet or intimately contact a solid surface (water beading on a waxed surfaces of a car is an example of poor wetting).
23
Q
Viscosity:
A
The ability of a liquid material to flow.
24
Q
Film thickness:
A
The minimum thickness obtainable by a layer of a material. This is particularly important to dental cements.
25
Surface energy:
The electrical charge that attracts atoms to a surface.
26
What is micro leakage and what causes it?
Leakage of fluid and bacteria caused by microscopic gaps that occur at the interface of the tooth and the restoration margins.
27
What is galvanism?
An electrical current transmitted between two dissimilar metals.
28
Review primary versus secondary bonds.
- Primary bonds: hold atoms together by the exchanging or sharing of electrons.
- Secondary bonds: no transfer or sharing of electrons; weaker.
29
Which bonds are the strongest?
Primary bonds are the strongest.
30
What are the three primary bonds known as?
The three types of primary bonds are known as ionic, covalent, and metallic bonds.
31
Define Preventive materials:
chemicals, devices, or procedures that reduce or eliminate disease or tooth destruction in the oral cavity.
32
Define Therapeutic Materials:
materials used to treat disease.
33
Define Restorative Materials:
Materials used to reconstruct tooth structure.
34
Define direct restorations:
fabricated directly in the mouth
35
Define indirect restorations:
fabricated outside of the mouth (commonly in a lab) and then placed in the patient’s mouth.
36
Permanent restorations:
expected to be long lasting replacement or missing, discoloured or damaged teeth.
37
Temporary restorations:
used for short periods of time (several days to weeks).
38
Intermediate restorations:
placed for a limited time, however, the time may extend from several weeks to months. Often used when there is other ongoing treatment such as orthodontics or implant therapy that is needed before a permanent restoration is required.
39
Mixing time:
the amount of time allotted to bring the components of a material together in a homogenous mix.
40
Working time:
the time permitted to manipulate the material within the mouth.
41
Initial set time:
The time at which the material can no longer be manipulated within the mouth.
42
Final set time:
The time at which a material has reached its ultimate state.
43
Chemical set materials:
materials that set through a timed chemical reaction with the combination of a catalyst and a base.
44
Light-activated materials:
materials that require a blue light source to initiate a reaction.
45
Dual set materials:
materials that polymerize by a chemical reaction that occurs when the material is mixed with a catalyst or that is initiated by exposure to blue light (or a combination of chemical and light reaction).
46
Define bio-aerosol.
A cloud-like mist that contains droplets, tooth dust, materials dust, and bacteria of a particle size smaller than 5um in diameter.
47
Acute chemical toxicity:
results from high levels of exposure over a short time. Effects are felt right away.
48
Chronic chemical toxicity:
repeated exposures to lower doses over a much longer time such as months or years. Effects include cancer.
49
Know the ways in which chemical can enter the body.
???Through the skin, eyes, ears, mouth, nose.???
50
Review proper PPE and safe handling of dental materials.
...
51
Self-cure:
two paste system; catalyst and base.
52
Light-cure:
operator controls working time; needs to be cured with blue light.
53
Dual-cure:
two paste system; contain both chemically and light activated materials; ensures material is set in areas of the tooth that cannot be reached by the light.
54
Which curing system is most common for resins?
Light cure is the most common.
55
Review glass ionomers
- Self-cured
- Fluoride releasing
- Bond to tooth structure directly (no bonding agent required)
- Uses: luting, restorative materials, and liners and bases for cavity preparation. (Similar chemical composition but different ratios of liquid and powder).
56
Organic resin matrix:
- most commonly used resin is bis-GMA (bisphenol-A-glycidyl dimethacrylate), reduces viscosity
- another resin that is used for the composite matrix is urethane dimethacrylate (UDMA).
57
Inorganic filler particles:
has several functions
- make composite stronger and more wear resistant (the higher the filler content, the stronger the material will be).
- help to reduce the amount of shrinkage that occurs
- help to control translucency of composite
- one important factor to keep in mind when choosing a composite resin material is the size of the filler particles, the smaller the particles, the smoother the surface of the composite will be after finishing and polishing and the longer it will be able to retain its luster.
58
Silane coupling agent:
used to provide a stronger bond between the inorganic fillers and the resin matrix.
- this coupling agent is silane, which reacts with the surface of the inorganic filler and with the organic matrix to allow the two to adhere to each other.
- good adhesion of the two is necessary to minimize loss of filler particles and to reduce wear.
59
Pigments:
inorganic; develop colors.
60
Macrofilled composites
used large particles as fillers.
- Large particles make composite difficult to polish.
- Generally stronger than composites with smaller filler particles.
- No longer widely used.
61
Microfilled composites:
small particles as fillers (weaker than macro)
- smooth and clean when polished
- not suitable for stress-bearing sites such as class I, II, and IV (incisal edge repair) due to their poorer physical properties.
62
Hybrid composites:
contain both large and microfine fillers.
- strong composite
- polishes well
- universal application (can use anterior and posterior)
- most manufacturers have stopped making these because of improved products have reduced the demand for them.
63
Microhybrids:
hybrids that were improved on by using even smaller particles.
- contain a mixture of small particles and microfine particles
- can contain higher filler content because microfine particles fill spaces between small particles.
64
Nanohybrids:
microhybrids with nanohybrid particles added.
- reduces resin (with less resin, composites shrink less with polymerization.
- strong composites
- can be polished to a high shine, and retain shine better than earlier composites.
65
HYBRIDS ARE ________: CAN BE USED AND POSTERIOR AND ANTERIOR PORTIONS OF THE MOUTH. _________, ______ ______, AND ______.
UNIVERSAL
ESTHETIC, WEAR RESISTANT, AND STRONG.
66
Nanocomposites:
contain particles that are 1000x smaller than conventional fillers.
-Have excellent polish ability, wear resistance, and maintain their luster long-term.
67
How are composite resins classified? (4).
- Filler amount (volume %)
- Particle size (um)
- Matrix composition
- Polymerization method
68
What is a silane coupling agent?
a chemical that helps to bind the filler particles to the organic matrix.
69
What is the purpose of the silane coupling agent?
to stick or adhere the particles to the matrix.
70
Polymerization:
is the chemical reaction that occurs when low molecular weight resin molecules called monomers join together to form long chain, high molecular weight molecules called polymers.
71
How can polymerization be done?
-activation of polymerization can be done chemically or by light or a combination of the two.
72
What does polymerization shrinkage refer to?
Polymerization shrinkage refers to the shrinkage that occurs when the composite is cured (polymerized).
73
What is the oxygen-inhibited layer?
very thin coating of uncured resin on the surface of the polymerized bonding resin.
- occurs in composites and sealants
- polymerization is inhibited where the surface is exposed to oxygen in the air
- once the composite resin and placed on top of the bonding resin its presence will exclude air and the uncured layer of the bond will cure when the composite is cured.
74
What is an oligomer?
- A polymer whose molecules consist of relatively few repeating units.
- (Resins) Thick liquids made up of two or more types of organic molecules.
75
What are the optimum levels of fluoride in community drinking water?
0.7 to 1.2mg/L or ppm
76
What are the types of desensitizing agents?
- occluding (plugging) the open dentinal tubules
| - desensitizing the nerve endings
77
Which kind of desensitizing agent acts directly on the nerve?
-desensitizing the nerve endings
78
What is fluorosis and how does it occur?
Enamel abnormality caused by consumption of excessive levels of fluoride
79
What are some causes of failed sealants? (4).
- Placing to much sealant material,
- surface contamination,
- air bubbles,
- vigorous scrubbing with application brush.
80
What are some possible causes of tooth sensitivity. (5).
- Exposed dentinal tubules to the oral cavity
- Temperature (usually cold)
- Sugar
- Acidic food
- Exposed root structure.
81
What are some indications for sealants.
- Indicated in permanent teeth if there was or are signs of disease in primary teeth
- Deep pits and fissures
82
What are the steps of sealant placement? (11).
1. Place isolation
2. Clean surface(s) to be sealed with pumice
3. Rinse and dry teeth thoroughly
4. Place etch for 20-30 seconds
5. Rinse with water for 10-15 seconds
6. If using cotton rolls carefully replace or ensure they are dry (could dry out with HVE)
7. Dry teeth thoroughly
8. Apply sealant according to manufacturer’s instructions
9. Cure for required length of time
10. Check with explorer
11. Remove isolation and thouroughly rinse.
83
What should an etched tooth surface look like?
Properly etched surface should appear frosty (white and chalky).
84
What type of etch is used for sealants?
Acid etchant should be used.
85
After placement of a sealant, what should you be checking?
- Ensure all pits and fissure are covered
- No holes in the material exist
- Sealant is well retained
* MORE MATERIAL CAN BE APPLIED IF NEEDED SO LONG AS THE SURFACE HAS NOT BEEN CONTAMINATED.*.
-Make sure to floss contact areas.
86
Topical fluorides:
strengthen teeth already present in the mouth, making them more decay resistant, while systemic fluorides are those that are ingested and become incorporated into forming tooth structures.
87
Systemic fluorides:
also provide topical protection because fluoride is present in saliva, which continually bathes the teeth.
88
Gel Fluroride:
given in trays for either 4 minutes or 1 minute (1 min not recommended by the ADA)
89
Foam Fluoride:
given in trays for either 4 minutes or 1 minute (1 min not recommended by the ADA)
90
Varnish Fluoride:
applied directly to surface of teeth. Pg. 100.
91
Acidulated phosphate fluoride (APF):
most often used with children as it has 12,300 ppm fluoride and has good uptake on enamel.
92
Two percent Neutral sodium fluoride (NaF):
contains 9000 ppm fluoride and is used more often with adults
93
APF is contraindicated for patients who...
have restorations made of porcelain, composite resin, glass ionomer, or compomer. It will also worsen root sensitivity in patients who are experiencing it as it dissolves plugs that block the dentinal tubules.
94
When should ZOE be used?IJIOSNOSCNIOCSNONCJONS
- Temporary cementation
- Temporary or intermediate restorations
- High and low strength bases
- Root canal sealers
- Or periodontal dressings
- Base or liner.
95
Review zinc phosphates.
- Set through an acid-base reaction
- Oldest of the cements
- Not widely used today (recognized for its problems with hypersensitivity)
- Powder liquid system:
- CAN ONLY BE MIXED ON A COOL GLASS SLAB!
96
Primary consistency:
less-viscous mix of materials that flows easily, can be drawn to a 1-inch string with a spatula when lifted from the center of its mass and is suitable for luting (cementing).
97
Secondary consistency:
thick, putty-like, condensable mix of material that can be rolled into a ball or rope and is suitable for use as an insulating base.
98
CLASSIFICATIONS OF DENTAL CEMENTS:
| Type I
- Luting cement
- Is designed to act as an adhesive to hold an indirect restoration to the tooth surface
- Adhere brackets to tooth surface during ortho treatment
- Includes permanent and temporary cements.
99
CLASSIFICATIONS OF DENTAL CEMENTS:
| Type II
-Involves material that could be used as a restorative material (IRM – intermediate restorative material) & dental sealants.
100
CLASSIFICATIONS OF DENTAL CEMENTS:
| Type III
-Include liners and bases that are placed within cavity prep.
101
Review how to mix zinc phosphate and why it is mixed that way.
- Mixed in increments
- Cool glass slab
- Exothermic reaction
- Figure 8
- Clean off spatula right away!!!!!!!!!!!!!!!!!
102
Review the composition of hybrid ionomers and how they differ from GIC.
Hybrid ionomer cements are similar to glass ionomer, however they have been modified with the addition of resin. The resin helps to improve the bond strength and to decrease the solubility.
103
Review the uses of a GIC:
permanent luting agents, luting of orthodontic bands and brackets, restorative materials, low and high strength bases, and core buildups.
104
Advantages of GIC: (4):
chemical adhesion to tooth and metal, fluoride release, moderately strong, easy to mix.
105
What is luting consistency?
Luting consistency = primary consistency
- not very viscous
- 1-inch string
106
What are the variables affecting final cementation? (4).
- Mixing time
- Humidity
- Powder-to-liquid ratio
- Temperature
107
How do you disinfect impressions?
- Rinse any debris from impression after removal from the mouth
- Disinfect with sodium hypochlorite, iodophor, Glutaraldehde, and phenyl phenol solutions
- Soak times can vary from 10-20 minutes depending on product used
- After disinfection, wrap in wet paper towel, plastic baggy & pack with Rx (written by DDS) to be sent to Dental Lab.
108
Hydrophilic:
an attribute that allows a material to tolerate the presence of moisture.
109
Hydrophobic:
an attribute that does not allow a material to tolerate or perform well in the presence of moisture
110
What armamentarium is needed for making an alginate impression?
- Alginate
- Water measurer
- Powder scoop
- Rubber bowl
- Wide-bladed spatula
- Impression trays (perforated) or solid trays including rim locks require alginate adhesive
- Utility wax ropes
- Saliva ejector
- Disinfecting solution
- Zippered plastic bag
- Paper towel.
111
Preliminary impression:
are made as a precursor to further treatment.
112
Final impression:
more accurate. Used for the fabrication of permanent restorations.
113
Elastic:
hydrocolloids; alginate and polyvinyl siloxane (PVS)
-alginate – preliminary
-polyvinyl siloxane: final impressions.
114
Inelastic:
older impression materials, seldom used in dentistry today because of the superior properties of elastic materials.
115
reversible hydrocolloid:
can pass repeatedly between highly viscous gel and low viscosity sol simply through heating and cooling.
116
irreversible hydrocolloid:
once converted to the gel form cannot be converted back into the sol, and is therefore said to be irreversible hydrocolloid material.
117
What are positive reproductions of dental structures known as?
Casts or Diagnostic casts.
118
What does “pouring” of the cast refer to?
Pouring is the process of vibrating the flow able gypsum product into the impression. This process must produce a cast that is the exact replica of the impression.
119
Impression plaster (type I):
- rarely used by todays dentists
- used as a final impression wash for edentulous arches
- can be used to mount casts on an articulator
120
Model Plaster (type II) -
- frequently used for diagnostic casts and articulation of stone casts.
- easy to manipulate
- least costly
- durable but realitivly weak
121
Dental Stone (type III):
-ideal for making full or partial denture models, orthodontic models, and casts requiring higher strength and abrasive resistance.
122
Dental stone, High-Strength/Low-Expansion (Type IV):
- suited for fabricating wax patterns for cast restorations.
- often referred to as densite or die stones.
- used to fabricate crowns and bridges
123
Dental stone High-Strength/High-Expansion (Type V)
- recent addition
- can withstand very high temperatures
- good to use with the newer base metals because of casting shrinkage
124
What is the initial setting time and final setting time of gypsum products?
Initial: 8-16 minutes
Final: 45min-1hour
125
What are the 2 parts of the diagnostic and working casts.
- Anatomic portion: teeth and gums.
| - Art portion: the base.
126
What are the three classifications of waxes?
- Pattern Waxes
- Processing Waxes
- Impression Waxes
127
What are the three pattern waxes?
- Inlay wax
- Casting wax
- Base plate wax
128
Inlay wax:
- Produces patterns of metal casting through lost wax technique.
- Comes in sticks, pellets, and tins.
- Is either green or blue.
- Hard, medium, and soft.
129
Casting wax:
- Used to construct the metal framework of partial and complete dentures.
- Comes in sheets and pre-formed shapes.
- Is similar to inlay wax but is not softened in the mouth.
130
Baseplate wax:
- Layered to produce the contours of the denture and hold the position on which denture teeth are set.
- Pink sheets.
131
What are the three processing waxes?
- Boxing wax
- Utility wax
- Sticky wax
132
Boxing wax:
- Used to form a box around impressions of the mouth when a cast is made
- Used to form the base (art) portion of a gypsum model.
- 1.5-inch red strip of boxing wax wrapped around an impression.
- Easily to manipulate at room temperature and is also slightly tacky so it can adhere to itself.
133
Utility wax (AKA: periphery wax).:
- Comes in long ropes that are easily manipulated at room temperature (sheets of long ropes).
- May be used with boxing wax to aid in the pouring of an impression
- Used to add to impression tray to enhance patient comfort.
134
Sticky wax:
- Comes in orange sticks that at room temperature are hard and brittle, but when heated under flame become soft and sticky
- Used to adhere components of metal, gypsum, or resin together temporarily.
135
What are the two impression waxes?
- Corrective impression wax
| - Bite registration wax
136
Corrective impression wax:
- Used in conjunction with other impression materials when taking edentulous impressions.
- Flows at mouth temperature.
- Used within another impression material to correct undercut areas, to fill in small voids, or to help develop a functional posterior palatal seal for maxillary complete denture impressions.
137
Bite registration wax:
-Used to produce bite registration for articulation of models.
