Post Test Flashcards
Free end saddles are liable to be displaced under occlusal pressure. This is a result of displaceability of the mucosa. Which technique is employed to try and prevent this by taking an impression of the mucosa under controlled pressure?
A. The functional load technique
B. The altered cast technique
C. The residual ridge technique
D. The total occlusal load technique
B. The altered cast technique
In a tooth-supported RPD with a circumferential cast clasp assembly, there is _____.
A. More than 180 degrees of encirclement in the greatest circumference of the tooth
B. A distal rest on the tooth anterior to the edentulous area
C. A mesial rest on the tooth posterior to the edentulous area
D. Only B and C
E. All of the above
E. All of the above
The component that is responsible for connecting the major connector with the rest and clamp assembly is:
A. The bar
B. The minor connector
C. The proximal plate
D. The guide plane
B. The minor connector
The superior border of a mandibular lingual bar major connector must be at least _____ mm below the gingival margins?
A. 1-2
B. 2-3
C. 3-4
D. 4-5
C. 3-4
The distance between the major connector on a maxillary RPD framework and the gingival margins should be at least _____.
A. 3mm
B. 2mm
C. 6 mm
D. 15 mm
C. 6 mm
NOTES:
WINDOW: 15 mm
From the following list of components of an RPD, which must be rigid?
A. Major connector, minor connector, and retentive clasp
B. Wrought wire clasp, rests, and minor connector
C. Minor connector, rest, and major connector
C. Minor connector, rest, and major connector
NOTES:
CIRCUMFERENTIAL CLASP ARM= 180 degrees encirclement
Retentive clasp arm: Buccal, Below the undercut, flexible, taper
Reciprocal clasp arm: Lingual, Above the undercut, rigid, uniform
Which is a main function of a guide plane surface contacted by a minor connector of an RPD?
A. Provides a positive path of placement and removal for an RPD
B. Can provide additional retention
C. Aids in preventing cervical movement
D. All of the above
E. Only A and B
E. Only A and B
Which type of clasps are generally used on a tooth-supported removable denture?
A. Circumferential cast clasp
B. Combination clasp
C. Wrought wire clasp
A. Circumferential cast clasp
The main function of the direct retainer of a removable partial denture is _____.
A. Stabilization
B. Retention
C. Support
D. Add strength to the major connector
B. Retention
NOTES:
Retention – resistance to vertical dislodging forces
Direct retainers
Indirect retainers
Stability (Bracing) – resistance to horizontal, lateral, or torsional forces
Minor connector
Proximal plates
Reciprocal arms and shoulders of circumferential clasp
Lingual plates
Rests
Support – resistance to vertical seating
Rests
Major connectors
Denture bases
Lack of reciprocation of a removable partial denture (RPD) clasp is likely to cause _____.
A. Tissue recession due to displacement of the RPD
B. Insufficient resistance to displacement
C. Fracture of the retentive clasp
D. Abutment tooth displacement during removal and insertion
D. Abutment tooth displacement during removal and insertion
The denture base of a mandibular distal extension RPD should cover _____.
A. The retromolar pads
B. All undercut areas and engage them for retention
C. The hamular notch
D. The pterygomandibular raphe
A. The retromolar pads
Inadequate rest-seat preparation for a removable partial prosthesis can cause _____.
A. Tooth mobility
B. Ligament widening
C. Occlusal rest fracture
D. Occlusal rest distortion
C. Occlusal rest fracture
Which of the following impression materials has the highest tear strength?
A. Polyether
B. Polysulfide
C. Addition silicone
D. Condensation silicone
B. Polysulfide
NOTES:
Polyether- most rigid
Polysulfide- most flexible; long setting time
Hydrocolloids- best wettability
Reversible hydrocolloid (Agar)
- setting reaction: gel→sol (Hytereresis)
Irreversible hydrocolloid (Aliginate)
Addition silicone (Polyvinyl siloxane)- most accurate elastomeric material
Condensation silicone- hydrophobic →least dimensionally stable
Which is true of a minor connector of an RPD?
A. Should be thin to not interfere with the tongue
B. Should be located on a convex embrasure surface
C. Should conform to the interdental embrasure
D. All of the above
E. A and C only
C. Should conform to the interdental embrasure
Which of the following is true of an occlusal rest for a removable partial denture?
I. One-third facial lingual width of the tooth
II. 1.5 mm for deep base metal
III. 2.0 mm labiolingual width of the tooth
IV. Floor inclines apically toward the center of the tooth
A. All of the above
B. I, III, IV
C. I, II, IV
D. III, IV
C. I, II, IV
In a Kennedy Class I arch in which all molars and the first premolar are missing and the rest of the teeth have good periodontal support, the preferred choice of treatment is _____.
A. A removable partial denture replacing all missing teeth
B. A fixed dental prosthesis replacing the missing premolar and a removable partial denture replacing the molars
C. Implant supported crowns replacing the first premolars and a removable partial denture replacing the molars
D. A and B are preferred choice of treatment over
E. B and C are preferred choice of treatment over
E. B and C are preferred choice of treatment over
Which of the following is(are) uses for the surveyor?
A. To aid in the placement of an intracoronal retainer
B. To block out a master cast.
C. To measure a specific depth of an undercut.
D. All of the above.
E. Only A and B are correct.
D. All of the above.
The minor connector for a mandibular distal extension base should extend posteriorly about _____.
A. Two-thirds the length of the edentulous ridge
B. Half the length of the edentulous ridge
C. One-third the length of the edentulous ridge
D. As long as possible
A. Two-thirds the length of the edentulous ridge
Which are characteristics of a major connector that contribute to health and well-being?
A. It is rigid and provides unification of the arch stability.
B. It does not substantially alter the natural contour of the lingual surface of the mandibular
alveolar ridge or the palatal vault.
C. It contributes to the support of the prosthesis.
D. All of the above.
E. Only A and B.
D. All of the above.
The component of an RPD that is spoon-shaped and slightly inclined apically from the marginal ridge of a tooth is the _____.
A. Indirect retainer
B. Minor connector
C. Rest
D. Lingual bar
C. Rest
All of the following are advantages of using a cast chromium-cobalt alloy for removable partial dentures except:
A. Corrosion resistance
B. High strength
C. High flexibility
D. Low specific gravity
C. High flexibility
The type or form of clasp is generally selected after:
A. Looking at the xrays
B. Talking to the patient
C. Surveying the cast
D. The initial try-in of the metal framework
C. Surveying the cast
Suprabuldge retainers (clasps) originate:
A. Below the height of contour
B. Above the height of contour
C. Above the 0.08 undercut
D. Above the occlusal surface of most molars
B. Above the height of contour
Which of the following indirect retainers will provide the best leverage against lifting of the denture base?
A. The one located the closest to the clasp tips which is located furthest from the edentulous area
B. The one located the furthest from the clasp tips which is located nearest to the edentulous area
C. The one located furthest from the clasp tips which is located furthest from the edentulous area
B. The one located the furthest from the clasp tips which is located nearest to the edentulous area
Which of the following Kennedy classes of removable partial dentures are not tooth-borne?
a. Class I, II
b. Class II, III
c. Class III, I
d. Class IV
a. Class I, II
It is important that a wrought wire clasp have an elongation percentage of:
A. More then 25%, allowing the clasp to bend without microstructure changes that could compromise its physical properties
B. More then 6%, allowing the clasp to bend without microstructure changes that could compromise its physical properties
C. Less then 6%, allowing the clasp to bend without microstructure changes that could compromise its physical properties
D. Less then 25%, allowing the clasp to bend without microstructure changes that could compromise its physical properties
B. More then 6%, allowing the clasp to bend without microstructure changes that could compromise its physical properties
The strength, hardness, and tensile strength of wrought wire is approximately:
A. 5% greater than the cast alloy from which it was fabricated
B. 25% greater than the cast alloy from which it was fabricated
C. 50% less than the cast alloy from which it was fabricated
D. 75% greater than the cast alloy from which it was fabricated
B. 25% greater than the cast alloy from which it was fabricated
The cingulum rest is usually confined to preparation on:
A. Maxillary lateral incisors
B. Maxillary canines
C. Mandibular lateral incisors
D. Mandibular canines
B. Maxillary canines
When designing a clasp assembly for the abutment tooth of a distal extension rpd, on which part of the crown surface should the retentive and reciprocal clasp arms be located?
A. Occlusal third
B. Middle third
C. Gingival third
C. Gingival third- as far apical as possible
Which primary design quality of the occlusal rest would categorize is as a positive rest
A. Allow no tilting of the appliance
B. Transmit stress down the long axis of the tooth
C. Form acute angles with the minor connectors that connect them to the major connector
D. Have a thickness of 1.5 mm
E. All of the above
C. Form acute angles with the minor connectors that connect them to the major connector
What degree of wall convergence during crown preparation will give the prosthesis optimal retention?
A. 1 to 3 degrees
B. 3 to 6 degrees
C. 4 to 8 degrees
D. 6 to 9 degrees
B. 3 to 6 degrees
The finish line of choice when fabricating an all ceramic crown is:
A. Shoulder
B. Bevel
C. Chamfer
D. Shoulder with bevel
A. Shoulder
NOTES:
Chamfer – best for metal margins
Shoulder – best for porcelain and ceramic margins
Feather edge/Bevel – Gold margins
Knife edge – tilted abutments
In a Provisional Fixed Partial Denture that is seated immediately after the extraction of a tooth, which of the following pontic forms will result in tissue blanching and provide the best support to the surrounding papillae while also providing for the best esthetic outcome following healing of the extraction site?
A. Sanitary (hygienic) pontic
B. Conical pontic
C. Ovate pontic
D. Modified ridge lap pontic
E. None of the above
C. Ovate pontic
All other factors are equal, the most retention is provided by the
A. Full crown preparation
B. Three-quarter preparation
C. Onlay
D. Inlay
A. Full crown preparation
Which of the following is the single most important predictor of clinical success of a cast post and core?
A. Amount of remaining coronal tooth structure
B. Post length
C. Post diameter
D. Positive horizontal stop
A. Amount of remaining coronal tooth structure
When preparing partial crown on a maxillary incisor, the proximal grooves should be parallel to the:
A. Long axis of the tooth
B. Gingival 2/3 of the labial surface
C. Incisal 2/3 of the labial surface
D. Middle third of the labial surface
C. Incisal 2/3 of the labial surface
The minimum acceptable crown:root ratio is:
A. 1:1
B. 1:2
C. 2:3
D. 1:3
A. 1:1
NOTES:
Ideal – 2:3
Acceptable – 1:2
Minimum – 1:1
A porcelain jacket crown will fracture when
A. Used in end-to-end occlusion
B. Fabricated for a mandibular incisor
C. Allow to contact the opposing teeth in centric occlusion
D. Subjected to tensile forces by opposing teeth
E. Subjected to compressive forces by the opposing teeth
D. Subjected to tensile forces by opposing teeth
The shoulder cervical finish
A. Greatly facilitate the adaptation of copper bands in making compound impressions.
B. Provide a well-defined finish line and adequate space in cervical region
C. Is the least conservative of the finish lines
D. Requires building up the short mesial end of the crown
C. Is the least conservative of the finish lines
A reverse 3⁄4 crown is most frequently fabricated for a:
A. Maxillary premolar
B. Mandibular premolar
C. Mandibular molar
D. Maxillary molar
C. Mandibular molar
NOTES:
7/8- maxillary molars, intact mesiobuccal surface
3/4- mandibular molars, intact lingual surface
For optimum periodontal health, restoration finish lines should be:
A. Within the sulcus at least 1.0 mm and away from the free gingival margin without encroaching on the biologic width
B. Terminated at the free gingival margin
C. Supragingival whenever possible
D. As far as possible subgingivally into the attachment apparatus
C. Supragingival whenever possible
The preparation for a full metal veneer crown is begun with occlusal reduction. There should be ____________ clearance on the functional cusps and about _____________ on the non-functional cusps.
A. 0.5 mm; 1.0 mm
B. 1.5 mm; 1.0 mm
C. 2.0 mm; 1.5 mm
D. 2.5 mm; 2.0 mm
B. 1.5 mm; 1.0 mm
NOTES:
OCCLUSAL REDUCTION
Porcelain/ PFM
Functional cusps: 2.0 mm
Non-functional cusps: 1.5 mm
Gold/ Metal
Functional cusps: 1.5 mm
Non-functional cusps: 1 mm
Which of the following teeth is the least desirable to use as an abutment tooth for an FPD?
A. Tooth with pulpal involvement
B. Tooth with minimal coronal structure
C. Tooth rotated and tipped out of line
D. Tooth with short, tapered root with long clinical crown
D. Tooth with short, tapered root with long clinical crown
After a few months that a dentist has restored an endodontically treated tooth with a cast-post crown, the patient complains of pain upon biting, the most probable cause is:
A. Vertical fracture
B. Psychosomatic
C. Premature contact
D. Loose crown
A. Vertical fracture
Which of the following is contraindicated in patients with cardiovascular disease
A. Alum
B. Ferric Sulfate
C. Epinephrine
D. Zinc chloride
C. Epinephrine
Metal in the crucible is melted and allowed to flow in the investment space.
A. Type Investing
B. Wax Pattern
C. Spruing
D. Type V
E. Casting
E. Casting
Which of the following surgical tissue management can be done without anesthesia
A. Electrocautery
B. Rotary curettage
C. Laser
D. None of the above
C. Laser
Which of the following is the correct biologic width
A. 2.40 nm
B. 2.04 nm
C. 2.40 mm
D. 2.04 mm
D. 2.04 mm
Which of the following is indicated in severely damged tooth with the mesiobuccal surface still intact
A. 3/4 crown
B. inlay
C. 7/8 crown
D. onlay
E. Laminate Veneer
C. 7/8 crown
NOTES:
7/8- maxillary molars, intact mesiobuccal surface
3/4- mandibular molars, intact lingual surface
What is the minimum amount of circumferential tooth structure above the margin to achieve Ferrule
A. 0.5 – 1.0 mm
B. 1.5 – 2.0 mm
C. 2.5 – 3.0 mm
D. 0.75 – 1.25 mm
B. 1.5 – 2.0 mm
A PRIMARY consideration for full coverage of abutment teeth to be used in the construction of
a fixed partial denture is the
A. Health of the mucous membrane
B. Health of the gingival tissues
C. Amount of supporting bone remaining
D. Caries susceptibility of the patient
E. None of the above
D. Caries susceptibility of the patient
When treatment planning for fixed prosthodontics, all of the following information can be obtained by studying diagnostic casts EXCEPT one. Which one is the EXCEPTION?
A. The length of the abutment teeth can be accurately gauged
B. The true inclination of the abutment teeth will be evident
C. The presence of periodontal pockets and the crown-to-root ratio of potential abutment teeth
D. Mesial-distal drifting, rotation, and faciolingual displacement of potential abutment teeth can be clearly seen
C. The presence of periodontal pockets and the crown-to-root ratio of potential abutment teeth
For patients with endodontically treated teeth, what is the best retainer to use
A. Full Crown
B. Onlay
C. Inlay
D. Partial Crown
A. Full Crown
What is the best margin to be used for porcelain
A. Feather edge
B. Knife edge
C. Shoulder
D. Chamfer
C. Shoulder
NOTES:
Chamfer – best for metal margins
Shoulder – best for porcelain and ceramic margins
Feather edge/Bevel – Gold margins
Knife edge – tilted abutments
The following is true regarding Inlay preparation except
A. Line angles should be sharp
B. Mesial and distal walls are diverging
C. Facial and lingual walls are diverging
D. None of the above
D. None of the above
Maxillary anterior teeth will give the best esthetic effect in a complete denture if arranged
A. Labially to the ridge
B. Lingually to the ridge
C. Over the crest of the ridge
D. To articulate with the mandibular anterior teeth placed over the crest of the ridge
E. None of the above
A. Labially to the ridge
In selecting anterior teeth for complete denture patients, one considers the patient’s
I. Facial size, shape and form
II. Age
III. Sex
IV. Physical features
A. I, II, III
B. I, II, IV
C. I, IV
D. AOTA
D. AOTA
Freeway space is synonymous with
A. Physiologic rest position
B. Interocclusal distance
C. Interdental arch space
D. Intermaxillary space
E. Both A ad B above
B. Interocclusal distance
Excessive vertical dimension may result in
A. A loss of muscle tone
B. Poor denture retention
C. A drooping of corners of the mouth
D. Creases wrinkles in the region of the mouth
E. Excessive trauma to the underlying support tissue
E. Excessive trauma to the underlying support tissue
Centric relation is a ____________ relationship.
A. Tooth to tooth
B. Mandible to condyle
C. Mandible to skull
D. Maxilla to skull
E. NOTA
C. Mandible to skull
NOTES:
CENTRIC RELATION
- Position in which condyles articulates with the thinnest avascular portion of their respective discs in the most anterior-superior position against the articular eminences.
In determining the posterior limit of a maxillary denture base, which of the following is on the posterior border?
A. Hamular notch
B. Fovea palatini
C. Hamular process
D. Vibrating line
E. Pterygomandibular raphe
A. Hamular notch
Which of the following will increase retention of a complete denture?
A. Xerostomia
B. Air chamber in midpalate
C. Foreshortened denture bases
D. Increases salivary film thickness
E. Accurate adaptation of the denture base to the mucosa
E. Accurate adaptation of the denture base to the
mucosa
Methods of selecting anterior teeth for a complete denture includes
I. Saving extracted teeth
II. Using pre-extraction records and photographs
III. Following the lines placed on the occlusion rims
A. I, II
B. I, III
C. II, III
D. I, II, III
E. NOTA
D. I, II, III
A patient who wears a complete maxillary denture complains of burning sensation in the palatal area of his oral cavity. This is an indication of excessive pressure by the denture in the:
A. Posterior palatal seal
B. Incisive foramen
C. Palatal mucosa
D. Hamular notch
E. External oblique ridge
B. Incisive foramen
The primary role of anterior teeth on denture is:
A. Occlusion
B. To incise food
C. Stability of the denture
D. Esthetics
D. Esthetics
Posterior teeth that are set edge to edge may cause:
A. Speech aberrations
B. Cheek biting
C. Gagging
D. Reduced taste
B. Cheek biting
Postural position is:
A. Ligament guided
B. Muscle guided
C. Tooth guided
D. Bone guided
B. Muscle guided
NOTES:
Centric Relation- Ligament guided
Resting or Postural- Muscle guided
Centric Occlusion- Tooth guided
The function of posterior palatal seal is:
A. To aid in balanced occlusion
B. To aid in insertion and removal
C. To ensure a complete seal thus helping in retention of a denture
D. Retention of mandibular denture by sealing its posterior margin
C. To ensure a complete seal thus helping in retention of a denture
Overextension of the posterior border of the denture causes:
A. Gagging sensation
B. Epulis fissuratum
C. Sagging of the corners of the mouth
D. AOTA
A. Gagging sensation
The greatest potential for wear exist between
A. Tooth and gold
B. Tooth and tooth
C. Porcelain and tooth
D. Porcelain to porcelain
E. Gold and gold
C. Porcelain and tooth
The relationship of denture base to bone that resist dislodgement of the denture in a horizontal direction is
A. Support
B. Pressure
C. Esthetics
D. Stability
E. NOTA
D. Stability
NOTES:
Stability – resistance of the denture against horizontal direction
Support – resistance of dentures to the force against the tissues/ resistance to vertical seating force
Retention – resistance to dislodgment of the denture away from the tissue
In determining the posterior limit of a maxillary denture base, which of the following is on the posterior border?
A. Hamular notch
B. Fovea palatini
C. Vibrating line
D. Retromolar pad
E. Pterygomandibular raphe
A. Hamular notch
When the mandible is in its physiologic rest position, the distance between occluding surfaces of maxillary and mandibular teeth or occlusion rims is
A. Centric occlusion
B. Vertical dimension
C. Interocclusal distance
D. Vertical dimension of rest
E. Occlusal plane
C. Interocclusal distance
The primary role of anterior teeth on a denture is:
A. To incise food
B. Occlusion
C. Esthetics
D. Stability of the denture
C. Esthetics
You are in the process of making a complete maxillary denture for a patient. Which of the following structure(s) will be the secondary support area(s)? (Choose 2)
A. Residual ridges
B. Palatal rugae
C. Incisive papilla
D. Maxillary tuberosity
E. Buccal vestibule
B. Palatal rugae
D. Maxillary tuberosity
NOTES:
MAXILLARY SUPPORTING AREAS
Primary
(1) Posterior part of the hard palate
(2) Posterolateral part of the residual ridge
Secondary
(1) Palatal rugae
(2) Maxillary tuberosity
The treatment plan for a patient indicates that both mandibular and maxillary immediate dentures are to be fabricated. The ideal way to do this is:
A. Fabricate the maxillary immediate denture first
B. Fabricate the mandibular immediate denture first
C. Fabricate the maxillary and mandibular immediate dentures at the same time
D. NOTA
C. Fabricate the maxillary and mandibular immediate dentures at the same time
The incisal edges of the maxillary anterior teeth should touch the wet/dry line of the lowerlip when enunciating which sound(s)?
A. “Th” sound
B. “F” and “V” sounds
C. “P” and “B” sounds
D. “S” sound
B. “F” and “V” sounds
NOTES:
SPEECH SOUNDS
(1) Fricative/ Labiodental sounds (f,v,ph)
- Contact between wet/dry line of lower lip and maxillary incisors
(2) Linguoalveolar/ Sibilant (s,z,sh,ch,j)
- Contact between the tip of the tongue and the lingual surface of the teeth
(3) Linguodental (t,d,n,l)
- contact between tip of tongue between maxillary and mandibular teeth
(4) Bilabial (b,p,m)
- Contact between upper and lower lip
(5) Gutteral (g,k)
- contact between throat and back of the tongue
The incisive papilla provides a guide for the anteroposterior placement of maxillary anterior denture. The labial surface of natural teeth are generally 8-10 mm anterior to this structure.
A. Both statement are true.
B. The first statement is true, and the second statement is false.
C. The first statement is false, and the second statement is true
D. Both statement are false
A. Both statement are true.
Which of the following statements is true concerning vertical dimension of rest?
A. VDR = physiologic rest position
B. VDR = position of the mandible when opening and closing muscle at rest.
C. VDR is postural relationship of the mandible and maxilla
D. VDR = the amount of separation of jaw separation controlled by jaw muscles when they are in relaxed state.
E. AOTA
E. AOTA
When border molding a mandibular complete denture, the extension of the lingual right and left flanges are best molded by having the patient ___________
A. Purse the lips
B. Wet the lips with the tongue
C. Open wide
D. Swallow
E. Count from 50 to 55
B. Wet the lips with the tongue
A good landmark for anterior-posterior positioning of the anterior maxillary teeth in a complete denture is the _____.
A. Residual ridge
B. Incisive papilla
C. Incisal foramen
D. Mandibular wax rim
B. Incisive papilla
Which one of the following is a purpose or characteristic of the posteror palatal seal?
A. Provides a seal against air being forced under the denture
B. Usually should extend posterior to the foveae palatinae
C. Improves the stability of the maxillary denture
D. Is carved deeper in the midpalatal suture area
A. Provides a seal against air being forced under the denture
The ____ is used as a guide to verify the occlusal plane.
A. Ala-tragus line
B. Interpupillary line
C. Camper’s line or plane
D. All of the above
D. All of the above
NOTES:
Ala-tragus line (Camper’s line or plane)- a line from the lower border of the ala of the nose to the upper border of the tragus of the ear.
Interpupillary line- a line that passes through the center of the pupil of each eye.
Which of the following conditions can be caused in an edentulous patient by an ill-fitting denture flange?
A. Papillary hyperplasia
B. Epulis fissuratum
C. Candidiasis
D. Fibrous tuberosity
B. Epulis fissuratum
For optimum esthetics when setting maxillary denture teeth, the incisal edge of the maxillary incisor should follow the _________.
A. Lower lips during smiling
B. Upper lips during smiling
C. Lower lips when relaxed
D. Upper lips when relaxed
A. Lower lips during smiling
Which impression material has the best wettability?
A. Polyether
B. Polysulfide
C. Hydrocolloids
D. Polyvinyl siloxane
C. Hydrocolloids
NOTES:
Polyether- most rigid
Polysulfide- most flexible; long setting time
Hydrocolloids- best wettability
Reversible hydrocolloid (Agar)
- setting reaction: gel→sol (Hytereresis)
Irreversible hydrocolloid (Aliginate)
Addition silicone (Polyvinyl siloxane)- most accurate elastomeric material
Condensation silicone- hydrophobic →least dimensionally stable
How does porcelain chemically bond to metal?
A. Interposition of an intermediate metal layer
B. Mixing of oxidized metal layer with porcelain oxides
C. Wetting of the porcelain onto the metal surface
D. Mixing of the metal atoms with the porcelain structure
B. Mixing of oxidized metal layer with porcelain oxides
What is the major component of an inlay wax?
A. Gum Dammar
B. Ceresin
C. Paraffin
D. Carnauba
C. Paraffin
NOTES:
Paraffin
- 40- 60% of inlay wax
Gum Dammar
- Reduce flakiness
- Increase surface finish
- Increase toughness
Ceresin
- modify toughness and carving characteristics
Carnauba/ Candelilla
- Decrease flow
- Improves glossiness
The impression material that is mainly composed of sodium or potassium salts of alginic acid is _____.
A. Polyether
B. Irreversible hydrocolloid
C. Polyvinyl siloxane
D. Reversible hydrocolloid
B. Irreversible hydrocolloid
NOTES:
Polyether- most rigid
Polysulfide- most flexible; long setting time
Hydrocolloids- best wettability
Reversible hydrocolloid (Agar)
- setting reaction: gel→sol (Hytereresis)
Irreversible hydrocolloid (Aliginate)
Addition silicone (Polyvinyl siloxane)- most accurate elastomeric material
Condensation silicone- hydrophobic →least dimensionally stable
One of the general requirements of a good luting agent is film thickness, the desired thickness is:
A. 10-20 microns
B. 25-30 microns
C. 35-40 microns
D. None of the above
A. 10-20 microns
The elastic modulus is a measure of:
A. Viscoelasticity
B. Toughness
C. Stiffness
D. Plasticity
C. Stiffness
Among the rubber based impression compounds, which is the least dimensionally stable?
A. Condensation Silicone
B. Addition Silicone
C. Polyether
D. Polysulfide
A. Condensation Silicone
NOTES:
Polyether- most rigid
Polysulfide- most flexible; long setting time
Hydrocolloids- best wettability
Reversible hydrocolloid (Agar)
- setting reaction: gel→sol (Hytereresis)
Irreversible hydrocolloid (Aliginate)
Addition silicone (Polyvinyl siloxane)- most accurate elastomeric material
Condensation silicone- hydrophobic →least dimensionally stable
The strength of dental investment for gold alloys is dependent upon the amount of:
A. Silica
B. Carbon
C. Gypsum
D. Alumina
C. Gypsum
It is the scavenger of oxides in an amalgam filling.
A. Zinc
B. Silver
C. Tin
D. Copper
A. Zinc
The procedure of removing surface tarnish or oxidation is:
A. Soldering
B. Boiling
C. Casting
D. Pickling
D. Pickling
NOTES:
Soldering- a process used for joining metal parts to form a mechanical or electrical bond
Boiling- the process by which a liquid turns into a vapor when it is heated to its boiling point.
Casting- Metal in the crucible is melted and allowed to flow in the investment space.
Pickling- the process of removing surface tarnish or oxidation.
The principal constituent of dental stone:
A. Beta-calcium sulfate hemihydrate
B. Alpha-calcium sulfate hemihydrate
C. Borax
D. Diatomaceous earth
B. Alpha-calcium sulfate hemihydrate
NOTES:
GYPSUM
TYPE 1: Impression plaster (Beta-calcium sulfate hemihydrate)
TYPE 2: Model plaster (Beta-calcium sulfate hemihydrate)
TYPE 3: Dental stone/ Hydrocal (Alpha-calcium sulfate hemihydrate)
TYPE 4: Die stone/ Densite (High strength stone)
TYPE 5: Die stone/ Densite (High strength, High expansion stone)
When porcelain is baked against metal, it should possess a:
A. High fusion expansion
B. High fusion temperature
C. Linear coefficient of thermal expansion less than, but close to, that of the metal
D. Linear coefficient of thermal expansion greater than, but close to, that of the metal.
C. Linear coefficient of thermal expansion less than, but close to, that of the metal
Carnauba is a:
A. Dental Wax
B. Gypsum products
C. Hydrocolloids
D. Porcelain cement
E. Flux
A. Dental Wax
Which of the following dental cement will chemically bond to enamel:
A. Zinc oxide-eugenol
B. Zinc phosphate cement
C. Zinc polycarboxylate cement
D. Zinc silico-phosphate cement
C. Zinc polycarboxylate cement
NOTES:
Glass Ionomer Cement
- Most biocompatible
- Bonds to tooth structure
- Fluoride releasing
- Translucent and tooth colored
Zinc Oxide Eugenol
- Neutral pH
- Low strength
- High solubility
- Contraindicated with composite resin
- Good temporary restorative material
Zinc Polycarboxylate
- High solubility to oral fluids
- Low compressive strength
Zinc Phosphate
- Very low pH
- High solubility to oral fluids
- Brittle
- Lack of adhesion to tooth
- opaque
Which component of porcelain serves as matrix for high fusing quartz?
A. Feldspar
B. Quartz
C. Kaolin
D. Metallic oxide
A. Feldspar
NOTES:
Feldspar -matrix for quartz; refractory skeleton
Quartz- strengthener
Kaolin- binder
Metallic oxides- impart shade
The gold content of an 18K alloy is:
A. 50%
B. 75%
C. 100%
D. 30%
B. 75%
NOTES:
24K= 100%
18K= 75%
12K= 50%
Which of the following cement bases has the highest elastic modulus to best support an extensive amalgam restoration?
A. Zinc phosphate
B. Zinc oxide eugenol
C. Zinc polycarboxylate
D. Glass ionomer
A. Zinc phosphate
NOTES:
Glass Ionomer Cement
- Most biocompatible
- Bonds to tooth structure
- Fluoride releasing
- Translucent and tooth colored
Zinc Oxide Eugenol
- Neutral pH
- Low strength
- High solubility
- Contraindicated with composite resin
- Good temporary restorative material
Zinc Polycarboxylate
- High solubility to oral fluids
- Low compressive strength
Zinc Phosphate
- Very low pH
- High solubility to oral fluids
- Brittle
- Lack of adhesion to tooth
- opaque
The metal ion in glass ionomer which has raised concern over neurotoxicity is
A. Magnesium
B. Aluminum
C. Tin
D. Zinc
B. Aluminum
A thin application of cavity varnish over the cut surface of a prepared tooth just prior to the cementation of a crown or a bridge with zinc phosphate cement will
A. Impede the seating of the restoration
B. Insulate the tooth against thermal change
C. Increase the possibility of thermal sensitivity
D. Reduce the possibility of irritation of the pulp
E. Increase the possibility of leakage of the restoration
B. Insulate the tooth against thermal change
Which of the following properties of dental materials is time-dependent?
A. Creep
B. Resilience
C. Elastic limit
D. Ultimate strength
E. Compressive strength
A. Creep
NOTES:
CREEP- time dependent plastic deformation or change of shape that occurs when a metal is subjected to a constant load near its melting point. This may be static or dynamic in nature.
RESILIENCE- maximum amount of energy without permanent deformation.
ELASTIC LIMIT- maximum stress a material endures without permanent deformation.
ULTIMATE STRENGTH - maximum stress before getting seriously damaged
COMPRESSIVE STRESS -results when the body is subjected to two sets of forces in the same straight line but directed towards each other.
The setting time of zinc oxide-eugenol impression paste may best be accelerated by:
A. Adding a drop of oleic acid to the mix
B. Chilling the mixing slab and the spatula
C. Adding a drop of water to the mix
D. Increasing the amount of eugeno
C. Adding a drop of water to the mix
Which of the following best describes quenching?
A. A metal is elevated to a temperature above room temperature and held there for a length of time
B. A metal is rapidly cooled from an elevated temperature to room temperature or below
C. Softening a metal by controlled heating and cooling
D. None of the above
B. A metal is rapidly cooled from an elevated temperature to room temperature or below
Eta phase in high copper amalgam is
A. Ag3Sn
B. Ag2Hg3
C. Sn7-8Hg
D. Cu6Sn5
D. Cu6Sn5
NOTES:
HIGH COOPER AMALGAM
Ag3Sn + Hg + AgCu
(gamma) (epsilon)
↓
Ag3SN + AgCu + Ag2Hg3 + Cu6 Sn5
(gamma-1) (eta)
LOW COOPER AMALGAM
Ag3Sn + Hg → Ag3SN + Ag2Hg3 + Sn8Hg
(gamma) (gamma-1) (gamma-2)
Thus,
Ag3Sn- gamma
Ag2Hg3- gamma 1
Sn7-8Hg- gamma 2
Cu6Sn5- eta
Dental plaster and stone are vibrated after mixing to:
A. Minimize distortion
B. Reduce setting time
C. Eliminate air bubbles
D. Increase the setting time
C. Eliminate air bubbles
This property allows the material to be drawn into wires without fracturing
A. elastic modulus
B. flexural strength
C. ductility
D. malleability
C. ductility
NOTES:
Elastic modulus (stiffness)- ability of a material to withstand changes in length when under lengthwise tension or compression
Flexural strength- the quality of bending easily without breaking.
Ductility- allows the material to be drawn into wires without fracturing
Malleability- ability to be hammered into thin sheets; % compression
