DH104 Midterm

A detailed image of dental tools, materials, and a human skull model, representing the study of dental hygiene and materials science.

DH104 Midterm Quiz

Test your knowledge with the DH104 Midterm Quiz, designed for dental health students and professionals. This quiz covers important topics in dental materials, restorative techniques, and the history of dentistry.

Prepare yourself for your midterm exams with these key features:

  • 100 carefully crafted questions
  • Multiple-choice format to assess your understanding
  • Score yourself immediately after completion
100 Questions25 MinutesCreated by BrushingTooth24
Until 1970 which of the following groups of dental auxiliaries were allowed to perform intraoral functions in all states
Dental hygienists
Certified dental assistants
Registered dental assistants
On-the-job trained dental assistants
Which of the following is not a classification of dental materials?
Preventive
Restorative
Biological
Therapeutic
The first acceptable amalgam formula was developed by _____ in 1895.
G.V. Black
Dr. Frederick McKay
Pierre Fuchard
Dr. William Taggart
What is today's approach to dental care referred to as?
Individualized care
Science-based dentistry
Comprehensive care
Evidence-based dentistry
What is Dr. Frederick McKay credited with?
Developing an acceptable formula for silver dental amalgam
Noting dental fluorosis in Colorado Springs
Demonstrating a casting method to produce gold inlays
The introduction of dental cements
Since 2005, the American Dental Association (ADA) Seal of Acceptance is awarded to _____ products.
Professional but not consumer
Both professional and consumer
Consumer but not professional
Neither professional nor consumer
Dental materials considered devices, as well as over-the-counter products sold to the public, are subject to control
Food and Drug Administration
Drug Enforcement Administration
Centers for Disease Control and Prevention
Department of Human and Health Services
Normal masticatory forces on the occlusal surfaces of molar teeth can increase _ pounds per square inch on a cusp tip.
280
1000
10,000
28,000
_____ force is applied when two surfaces slide against each other in opposite directions.
Compressive
Shearing
Tensile
Axial
Stress is the amount of force exerted from within an object, and _______ is the amount of change that the force has produced.
Strain
Tension
Compression
Chemical bonding
Which of the following statements is correct about fatigue failure?
It is not a factor for restorative dental materials.
It is not dependent on conditions in the oral cavity.
It occurs as the result of a large, single-force appli- cation.
It occurs as the result of microscopic flaws that grow over time.
The normal resting pH of saliva ranges from 6.2 to _____, which is neutral. 20sec
1
6.6
7
14
The staining of resins and acrylics from repeated exposure to coffee, tea, and other dyed beverages is due to
Compressive forces.
Water sorption.
Galvanism.
Tarnish.
Which of the following is true of galvanism?
 
A) It is an electrical current transmitted between two similar materials 
 
B) It is observed in patients with composite resin but not silver amalgam restorations. 
 
C) Galvanic stimulation will decrease with time as oxides form on the surface of the metal. 
 
D) The salts of the saliva inhibit the movement of electrical current from one type of metal to another. 
 
A
B
C
D
What could excessive expansion of a restorative material result in?
Corrosion
Galvanism
Fracture of cusps
Leakage of fluid and bacteria into the gaps
What is percolation?
 
 
 
The rate at which heat flows through a material
A form of chemical rather than mechanical retention
Something that help seal the interface between tooth & restorative material
The repeated shrinkage and expansion of the restoration during ingestion of cold and hot fluids that can allow the ingress of bacteria between the tooth and restoration
Which of the following is the best thermal conductor?
Gold
Dentin
Enamel
Ceramic
Which of the following restorative material has a coefficient of thermal expansion/ thermal conductivity close to enamel?
Gold
Amalgam
Porcelain
Composite resin
Which of the following statements is true for the property of wetting as related to dental materials?
The Teflon surface of cooking equipment has good wetting.
A thin film of dental cement is desirable to cement crowns.
Liquids generally spread better over low surface en- ergy surfaces.
A surface has high surface energy when liquids bead up on the surface.
1, 2
1,2,3
1,2,3,4
2,3,4
Some materials give off heat when mixed. What is this called?
Chemical reaction
Exothermic reaction
Thermal conductivity
Coefficient of thermal expansion
Which term describes a materials resistance to flow (how thin/thick a material is)?
Density
Viscosity
Flowability
Thixotropic
Which type of bond occurs when two atoms share electrons in their outer shell, creating full shells for both?
Ionic bond
Covalent bond
Metallic bond
Hydrogen bond
Which of the following forms of matter has/have both shape and volume?
1. Solid
2. Liquid
3. Gas
1, 2, 3
1, 2
2, 3
1
Which of the following is the hardest material?
Enamel of a tooth
Cementum of a tooth
Cast gold restorative material
Composite resin restorative material
Which of the following are considered to be therapeutic dental materials?
Partial and complete dentures
Fluorides and pit and fissure sealants
Fillings, inlays, crowns, bridges, and implants
Medicated bases and topical treatments for periodontal disease
Which of the following is an example of a direct restorative material?
Porcelain inlay
Cast gold crown
Ceramic implant abutment
Silver dental amalgam restoration
Dental stone begins with _____ components.
Water and powder
Liquid and powder
Paste and liquid
Paste and paste
_____ time is the time permitted to manipulate the material in the mouth.
Mixing
Working
Initial set
Final set
Dual set materials utilize _____ setting reactions.
Both light-activated and chemical
Light-activated but not chemical
Chemical setting but not light-activated
Neither light-activated nor chemical
In general, _____ temperature and _____ humidity will accelerate the reaction of the material.
High; high
High; low
Low; high
Low; low
What is the maximum amount of stress a material can take before breaking?
Ultimate capacity
Ultimate strength
Material hardness
Maximum elasticity
Metals that can withstand dimensional change without breaking are:
Tough.
Ductile
Resilient.
Malleable.
What is the measure of the weight of a material as compared with its volume?
Density
Viscosity
Hardness
Resistance
A _____ material will flow more easily under mechanical pressure.
Viscous
Thixotropic
Resistance
Therapeutic
Which of the following would be considered an indirect placement restorative material?
Gold
Glass ionomer
Amalgam
Composite resin
Who has the responsibility of assessing hazardous chemicals and then passing the information to consumers?
Occupational Safety & Health Admin Occupational Safety and Health Admin.
Organization for Safety and Asepsis Procedures
Centers for Disease Control and Prevention
Chemical manufacturers
Acute chemical toxicity results from _____ levels of exposure over a _____ period of time.
High; long
High; short
Low; long
Low; short
Which of the following is essential to prevent severe injury if phosphoric, hydrofluoric, or hydrochloric acid is splashed on the skin, eyes, or clothing during manipulation of various dental materials? 
 
Calling 911
Flushing with water
Placing an ointment and a bandage over the affected area
NIOSH approved dust and mist respirator facemask
If eyes are exposed to acids used during manipulation of various dental materials, how long is it recommended for the exposed individual to use the nearest eye wash station and flush the eyes with water? 
1 minute
5 minutes
10 minutes
15 minutes
Which part of the chemical hazard communication program must describe how chemicals are handled in the workplace? 
Written program
Employee training
Chemical inventory
Labeling of containers
What does SDS stand for?
Safety Data Sheet
Serving Dental Systems
System of Dental Services
Serving Dental Structures
Staff training for a hazard communication program is required once _____ for all continuing employees.
A month
A year
Every 3 years
Every 5 years
Which particulates are smaller than 50 microns?
Dust
Mold
Splatter
Aerosols
The most commonly used etchant or conditioner for tooth bonding is _____ in concentrations ranging from 10% to 38%.
Acetic acid
Phosphoric acid
Hydrochloric acid
Sodium perborate
Which of the following statements is true for bonding orthodontic brackets?
 
A) Orthodontic brackets have replaced bands for many uses, especially in the posterior part of the mouth. 
 
B) Because brackets cannot be used with conventional cements, they must be bonded to the enamel using adhesive materials. 
 
C) Only self-cured adhesive bonding resins can be used for bonding orthodontic brackets. 
 
D) Orthodontic brackets must be direct bonded; there is no indirect method of application of brackets. 
A
B
C
D
When are post placed within the root of endodontically treated teeth to retain dental material used to build up the teeth?
When the root needs strengthening
When the crown-to-root ratio is poor
When a multi-rooted tooth is involved
When coronal tooth structure is inadequate for retention a crown & build-up is needed
Overdrying of the dentin after etching can cause:
Dehydration.
Desiccation
Tooth hypersensitivity.
Desiccation and tooth hypersensitivity
The etched surface of a permanent tooth should have a/an _____ appearance when dried.
Frosty
Opaque
Darkened
Transparent
Which of the following is true of the smear layer?
It is composed exclusively of bacterial plaque.
It is easily washed off with an air-water spray.
It forms on the external surface of uncut enamel.
It interferes with the formation of a bond to dentin & needs to be removed.
For how many seconds should dentin be etched?
10
20
40
60
The oxygen-inhibited layer is a very thin coating of uncured resin. Where is it found?
Within the dentinal tubules
At the base of the polymerized bonding resin
On the surface of the polymerized bonding resin
Within intertubular and peritubular dentin, but not within dentinal tubules
Composite resins are composed mainly of an organic resin matrix and inorganic silica filler particle join together by a_______ coupling agent. 
Silane
Colloidal
Surfactant
Hydrophobic
In general, it is recommended that light-cured composite be placed in increments no thicker than ____ mm.
1.0
2.0
4.0
8.0
Which part of the tooth is generally closest to the dentin in color?
Body
Cervical
Incisal area of anterior teeth
Occlusal area of posterior teeth
Which of the following is used to prepare the dentinal tooth surface for placement of glass ionomer cement?
35% phosphoric acid
10% polyacrylic acid
A rotary cutting instrument such as a diamond bur
Nothing; it bonds to calcium without surface prepa- ration.
What is the risk to our eyes after repeated low-level exposure to the blue curing light?
Cataract
Blindness
Detached retina
Macular degeneration
Which of the following materials is fluoride releasing?
Porcelain
Glass ionomer
Composite resin
What is the organic matrix of composite resins made up of?
BIS-GMA
Glass
Silica
Quartz
What is the best way to take a patient's color/shade?
Using a shade guide
Moistening the teeth
Curing a small quantity to enamel
All are good choices.
The accepted optimal level of fluoride in the drinking water is ____ mg/L or parts per million.
0.01
0.7
0.12
0.5
Where is fluoride's greatest anticaries benefit gained?
Topical fluoride exposure before eruption
Systemic fluoride exposure before eruption
Topical fluoride exposure after the teeth have erupted
Systemic fluoride exposure after the teeth have erupted
Which of the following is the most commonly noted side effect with chlorhexidine gluconate as an antibact mouth rinse?
Leukoplakia
Brown stain
Geographic tongue
Median rhomboid glossitis
Which of the following are the teeth from which sealants are most frequently lost?
First premolars
Second premolars
First molars
Second molars
Which of the following is the worst type of sealant failure?
All of the sealant is lost.
Part of the sealant is lost.
The sealant remains in place but leaks.
Too much sealant is placed, resulting in excess material in the contact
Which of the following causes of tooth sensitivity may be successfully treated with a desensitizing agent?
Dental caries
A cracked tooth
A leaking restoration
Exposed dentinal tubules
Which of the following desensitizing agents is thought to work by passing through the dentinal tubules to the pulp and acting directly on the nerve? 
Fluoride compounds in toothpastes, gels, or solutions
Ferric or potassium oxalate solutions
Chemical solutions containing resin
Potassium nitrate
At what pH will tooth demineralization occur?
3.5
4.5
5.5
6.5
What is the proper order for the steps of applying sealant?
Etch, clean, cure, seal
Clean, etch, seal, cure
Etch, seal, cure, clean
Clean, seal, cure, etch
In conjunction with fluoride, which product wouldaid in tooth remineralization?
Phenolic compounds
Chlorhexidine
Essential oils
Antibiotics
Where is resin infiltration most successfully used?
In pits and fissures
In early cavitation
On interproximal surfaces
On smooth surface white spots
Which factor would contraindicate dental sealants?
Deep, uncoalesced grooves
Shallow, well-coalesced grooves
Adult patients with high caries risk
What is the main advantage of the combination of porcelain and metal for fixed crown and bridge prosthodontics?
 
A) Direct fabrication of the restoration in the patient's mouth. 
 
B) Superior esthetics when contrasted with all-porcelain jacket crowns. 
 
C) The use of high-fusing porcelain for superior bonding to tooth structure. 
 
D) The strength and durability produced by the bond between a metal internal core and the porcelain covering. 
 
 
A
B
C
D
Which of the following is the first layer of porcelain applied to the metal during fab of porcelain metal restorations?
Body porcelain
Incisal porcelain
Opaque porcelain
Translucent porcelain
Why do all-ceramic crowns have a more lifelike appearance than porcelain-bonded-to-metal crowns?
Have an opaque layer
Do not have an opaque layer to hide metal
Utilize high-fusing rather than low-fusing porcelain
Are cemented with different cements than porce- lain-bonded-to-metal crowns
What is the major drawback of all-ceramic restorations in the posterior of the mouth?
Fracture rate
Lack of esthetic appearance
Difficulty in creating an acceptable interproximal contact area
Inability 2 create an adequate occlusal anatomy vs the opposing occlusion
Which of the following is true of computer-aiding machining (CAD) for crown and bridge techniques?
 
A) An optical scanner is used for the impression, no die needs to be poured, and no temporary crown is necessary. 
 
B) A porous ceramic core is infiltrated with molten glass by capillary action. 
 
C) Ceramic powder is mixed with a water-based liquid to form a mass that is pressed onto a porous refractory die. 
 
 
A
B
C
What is the primary cause of porcelain failure?
Occlusal loading
Firing defects
Oral habits
Poor diet
When porcelain particles are melted and fused to metal, what is the process known as?
Firing
Smelting
Bonding
Sintering
Which of the following is most challenging when placing veneers?
The patient has a diastema.
The natural tooth structure is dark.
The teeth are rotated out of occlusion.
The adjacent teeth have been bleached.
The completed impression forms a_____reproduction of the teeth and tissues & model forms a _____ replica of the teeth & tissue.
Positive; positive
Positive; negative
Negative; positive
Negative; negative
Which of the following is the most widely used dental impression material?
Reversible hydrocolloid
Irreversible hydrocolloid
Addition of silicone impression material
Condensation silicone impression material
A properly extended maxillary alginate impression tray will extend posteriorly enough to include which oral landmark
Retromolar pad
Hamular notch
Soft palate
Uvula
Fixed alginate should be loaded into the impression tray in _____ increments as _____ as possible.
Large; quickly
Large; slowly
Small; quickly
Small; slowly
What is the ideal time frame for pouring an alginate impression?
An hour
A day
A week
A month
Which of the following is true of vinyl polyether silicone?
It is hydrophobic.
It flows well but has low tear strength.
It can tolerate a little moisture around the preparation.
It is available in three viscosities: light, monophase, and heavy.
Which of the following is an elastic impression material?
Impression wax
Impression plaster
Vinyl polyether silicone
Dental impression compound
Why would a dentist choose to use an addition silicone over a condensation silicone?
Addition is stronger than condensation.
Addition does not distort as badly.
Addition is cleaner to use.
Addition tastes better.
When should impressions be disinfected?
At the dental lab check-in
Before rinsing with water
At the chairside upon removal
For an hour before pouring in gypsum
Which of the followin dental gypsum product will require the least water for mixing& will have the highest final density
Impression plaster (Type I)
Model plaster (Type II)
Dental stone (Type III)
Dental stone, high strength (Type IV)
Which material is able to withstand the high heat and stress produced when molten metal is forced into molds to form indirect restorations? 
Dental investment
Model plaster
Dental stone
Die stone
The _____ the particles of gypsum powder are, the weaker and less resistant the final product is to abrasion.
Smaller, more irregular, and denser
Smaller, more regular, and more porous
Larger, more irregular, and more porous
Larger, more regular, and denser
Which of the following statements is true concerning the mixing of plaster and stone materials?
 
A) The measures amount of powder is placed into the mixing bowl and the water dumped into the powder. 
 
B) The measured amount of water is placed into the mixing bowl and the powder is slowly sifted into the water. 
 
C) The measured amount of water is placed into the mixing bowl and the powder is dumped into the water. 
 
A
B
C
What does it mean when freshly mixed gypsum loses its gloss?
Beginning of the working time
Final compressive strength
Initial set
Final set
1,2,3
1,2
2,3
1
Which of the following correctly represents the stages seen when acrylic powder & liquid are mixed together?Initial set
Dough, sandy, rubber, and stringy
Stringy, sandy, dough, and rubber
Sandy, stringy, dough, and rubber
Rubber, stringy, dough, and sandy
Polimerization of chemical-cured acrylic resins is set into action when the tertiary amine in the liquid activates the ________ in the powder to produce free radicals. 
Plasticizers
Hydroquinone
Benzoyl peroxide
Glycol dimethacrylate
Polymerization shrinkage is seen most readily in which of the following areas of a heat-cured acrylic resin denture?
Labial flange
Alveolar ridge
Palatal
Hamular notch
A specialized aspect of a/an _______ practice may include the fabrication of maxillofacial prostheses to replace facial tissues lost as the result of trauma, disease, surgery, or birth defect. 
Prosthodontic
Periodontic
Endodontic
Orthodontic
Why must dentures be relined periodically?
Dentures absorb odors from plaque and food.
Dimensional changes in acrylic occur.
Alveolar ridges shrink over time.
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