PRDS 126 Flashcards
Not component of RPD
Rest seat
Support for RPD is best provided by
rest; maxillary major connector for tooth & tissue borne RPD; indirect retainers
Marginal ridge reduction - Gold alloy? Metal base?
Gold = 2.0 mm
Metal base = 1.5
A guideline for the width of a properly prepared occlusal rest seat is one third the distance between the cusp tips or one half the buccal/lingual width of the tooth.
FALSE – 1/2 cusp tips, 1/3 buccal/lingual width of tooth
You are preparing an occlusal rest seat on a mandibular molar. Which of the burs listed below would be used LAST?
Medium Round Diamond
A surveyor
analyzing & delineating the contours of abutment teeth & associated structure before designing a removable
Undercut gauges come in various sizes, either 0.010 inch, 0.020 inch or 0.030 inch.
TRUE
RPD retention
Direct retainers (clasp assemblies, attachments applied to abutment tooth)
The location of the internal finish line is the same for maxillary and mandibular tooth- borne RPD’s or tooth borne segments of maxillary and mandibular tooth-mucosa borne RPD’s.
TRUE
The most common type of clasp used on TOOTH BORNE RPD’s in the anterior part of the mouth where esthetics usually is a concern is the?
Clasp combination cast circumferential & cast bar clasp
The Kennedy Class II, mod. 2 type of removable partial denture has how many partially edentulous spaces?
3
Movement of tooth borne removable partial dentures occurs around a fulcrum line axis.
FALSE – tooth and tissue borne
Which of the following is considered a primary supporting area for the maxillary edentulous arch?
posterior ridge crest + horizontal hard palate
Which of the following is considered a primary supporting area for the mandibular edentulous arch?
pear-shaped pad + buccal shelf
Fulcrum lines would NOT be associated with which of the Kennedy Classifications listed below?
Kennedy Class III (tooth borne)
For which of the maxillary Kennedy Classifications listed below would a modified palatal plate major connector be indicated?
Kennedy Class II
The general type of major connector chosen for a patient presenting with maxillary Kennedy Class III partial edentulism is
straptype
Which of the mandibular major connectors listed below contributes the most support to the extension base RPD?
NONE - no support from labial bar, lingual bar, lingual plate, sub-lingual bar (all are major connectors)
Which type of denture base is NOT associated with posts, loops or beads to help retain artificial denture teeth?
Retentive mesh – others, open lattice, metal base
Metal bases are commonly utilized to replace partially edentulous segments that are longer than molars mesiodistally.
FALSE – shorter than molars
Which of the direct retainers listed below is considered to be STRESS RELEASING?
RPI, combination cast circumferential and wrought wire
The first clasp of choice for abutment teeth on a maxillary Kennedy Class I RPD is?
RPI
Which of the components listed below is not a type of indirect retainer?
REST – indirect retainers: minor connector, proximal plate, lingual plate major connector, lingal bar major connector
A gold framework would weigh ____?___ how much more than a base metal framework of the same size.
2x as much
The major constituent of chromium-cobalt base metal alloys for RPD frameworks is chromium.
FALSE
Frameworks for RPD’s are waxed and cast directly on the master cast.
FALSE
Cuspid rise and anterior disclusion is an ideal occlusal scheme for mandibular tooth borne partial dentures opposing maxillary complete dentures.
FALSE
Master impressions for RPD’s should be made in
stock metal impression trays with alginate
A CERAMOMETAL restoration is a legitimate restoration to consider restoring an anterior tooth discolored in response to endodontic treatment
TRUE – not like Emax
Which prep margin is most appropriate for an Emax restoration?
Heavy chamfer
What is the chemical nature of Emax?
Lithium Disilicate
Emax is NOT an ideal restoration for a tooth that has been significantly discolored due to
endo treatment
TRUE
What is the minimal amount of axial reduction required for Emax? incisal reduction?
1.0 mm; 2.0 mm
Minimum amount of incisal reduction required for an Emax restoration?
1.5 mm – max: 2.0 mm
When drawing design sequence for RPD framework on a cast, the 2nd component you should draw is?
Minor connectors – 1st: rests
Term is used to describe bone’s response to loading forces
Bone index
For traditional Class II composite prep, where would you place retention grooves
Composite traditional prep doesn’t require retention grooves
In considering the following teeth for a ceramometal restoration, which would most likely accommodate the optimal amount of facial reduction
Tooth #11
Etching with 35% phosphoric acid longer than 20 second will:
A, B, C - increase sensitivity, coagulate collagen, open dentinal tubule excessivey
Ceramometal restoration needs porcelain facial margin, and the facial should should be how big
1.2 -1.5 mm
Primary supporting areas for mandibular arch is the posterior ridge crest.
FALSE – pear-shaped pad + buccal shelf
Fulcrum line access does not exist for this type of RPD:
Kennedy Class III - tooth borne
For proper examination and diagnosis how many casts of each partially edentulous arch should be made for patients requesting RPD therapy?
TWO
The advantages of direct composite veneers are:
They provide high flexibility in design and adjustments
When adding composite:
Always move your instrument from the composite towards the margin
Micro-fine diamond burs are used to:
Shape and pre-polish the composite
Posterior composite techniques require:
That a maximum of 2mm of composite be placed sequentially
In Class II Posterior composite designs:
All – It is okay to have the pulpal floor remain in enamel; As long as we are not in contact areas, it is okay to have a depth of less than 1.5mm; The minimal axial depth is 1mm; Healthy pits and grooves are not removed
Microfilled composites:
Provide high polishability, luster, and translucency
Regular carbide burs are ideal for shaping to a prefinish
FALSE
The use of all-ceramic occlusal surfaces versus metal occlusal surfaces can result in:
removal of more tooth structure to accommodate porcelain (2.0 mm); abrasion of the opposing occlusal surfaces (i.e. both natural teeth and gold); fracture and costly repair of occlusal porcelain
For porcelain occlusals, a minimum of ___?___ occlusal reduction is necessary.
2.0 mm
Maxillary second molars and mandibular molars may require metal ceramic crowns if a patient will not accept all metal crowns on those teeth.
TRUE
The minimal cusp reduction for a functional cusp when preparing a tooth for an extracoronal amalgam is:
2.0 mm
When placing a trough for additional retention in a vital tooth:
B,D,E,F - use inverted cone, place it parallel to DEJ, place entirely in dentin, place it 0.5 mm in from DEJ
To treatment plan a hygienic pontic, what is the minimal interocclusal space that is required?
5.0 mm
How much more deflection will a fixed partial denture with 3 pontics experience when compared with a fixed partial denture with 1 pontic?
27 x more deflection
Which of the following are methods of connecting a pontic to a retainer?
ALL - cast connector, soldered connector, non-ridged connector
In which discipline of dentistry is a precision attachment most useful?
RPDs
You are treatment planning a fixed partial denture to replace teeth #19, 20, 21. Tooth #23 can be considered a good candidate for a secondary abutment.
FALSE
In treatment planning a fixed partial denture replacing teeth #19, 20, 21 you have decided to use tooth #17 as a secondary abutment. Preparing tooth #18 for a full veneer gold crown and tooth #17 for a partial veneer gold crown is an acceptable treatment plan.
FALSE
Which of the following statements about non-ridged connectors is not correct?
It is usually placed in the mesial surface of the anterior abutment* – CORRECT OPTIONS: It usually draws with the distal abutment; It is usually placed in the distal of the pier abutment
If we want to make a Class IV Restoration have a translucent incisal edge the composite should:
be translucent on both the lingual and facial incisal areas
To prevent composite from sticking to instrument, it’s best to:
Wipe instrument w/gauze and keep it clean before manipulating composite
Before polishing our composite veneers, we should always end our pre-finishing with a:
15 micron (EF) diamond bur
What is the purpose of using a polyacrylic acid and pre-conditioning liquid?
Removing smear layer when placing a glass ionomer
After polishing a Class IV composite, Dr. Oops notices the incisal edges are too grey and transparent. What might he have overlooked:
ALL – tried composite pre-restoratively but forgot to light cure as he chose his shade; instead of A2 dentin, used A2 compsosite; used microfilled composite instead of hybrid composite; color matched as the tooth was rubber dammed and dehydrated
During color matching composites for a Class IV restoration, one of the first aspects to check for is:
The tone (in enamel) which determines the amount of gray in a tooth
When polishing your composite, the jiffy brush should be used
dry and hard
Tooth #8 prep for ceramometal restoration, how much incisal reduction is required?
1.5 -2.0 mm
Incisal 1/3 of the facial surface of the tooth #22 opposes lingual surface of #11, how much facial reduction is required in this area if prepping tooth for an emax?
1.0-1.2 mm (PBM = 1.0 - 1.5 mm)
Ceramometal restorations generally require more tooth reduction than do Emax restorations:
TRUE
Zirconia crowns are more durable than emax restorations:
TRUE
Zirconia crown can be cemented with traditional luting cements
TRUE
Empress restorations are less durable than emax restorations:
TRUE (empress = high glass)
On the mandibular framework shown here, circumferential clasps have been used on the canine, premolar and molar. Which of the following statements regarding the clasping is true?
If the patient has esthetic concerns a combination bar clasp should be designed for the canine
Referring to the pic below of the RPD framework, indirect retainers on teeth #22 and #27 function when
A & B (indirect retainer placement)– patient removes RPD; patient chews on something sticky
Reciprocation is the resistance to horizontal forces exerted on the tooth by an active retentive clasp. It is related to the timing of the contact between the bracing and retentive clasp arms in order to prevent undue forces of the abutment teeth during insertion and removal of the RPD.
TRUE, TRUE
Your patient has partially edentulous arch shown. Undercuts of teeth #21 and 28 are on the mesiofacial surfaces. Most common clasp assemblies used if esthetics is a factor would be:
Combination bar clasp
Your patient’s partially edentulous arch is shown below, esthetics are a concern for the patient. Where should the combination bar clasp be used?
NONE (18, 20, 29, 20&29) – there is a distal extension base from the missing teeth 30-32, because there isn’t stress release, a combination bar clasp cannot be used.
Your patient exhibits the partially edentulous arch form. Tooth #29 is tilted mesially. The undercut is on the mesiofacial surface. What would be the WORST clasp assembly to choose for #29?
RPI (mesial tilt eliminates required underecut gingival to distal guiding plane)
The most common type of clasp used on tooth borne RPD’s in the anterior part of the mouth where esthetics usually is a concern is the –?
Clasp combination cast circumferential cast bar clasp
Which of the direct retainers listed below is considered to be STRESS RELEASING?
RPI and combination cast circumferential and wrought wire
Which of the components listed below is not an indirect retainer?
Lingual BAR major connector – indirect retainers (rest, minor connector, proximal plate, lingual plate major connector)
Which of the following is not an advantage of base metal alloys over Type IV gold alloys for partial dentures?
High Modulus
Which of the following is the most important advantage of CoCr over NiCr base metal alloys for a dental prosthesis ?
Biocompatibility
Which of the following is not an important advantage of titanium alloys for a dental prosthesis
Low fusion temperature
The landmark that is reproducible for every tooth and gives the closest approximation for the roof of the pulp chamber is the?
CEJ
Lateral canals are most commonly found in the
apical third.
What is the minimum amount of body porcelain needed to make an porcelain bonded to metal restoration esthetic?
0.4mm
What is the minimum reduction of the facial surface of a tooth that will allow the fabrication of a porcelain bonded to metal restoration?
1.0mm
When preparing a tooth for a porcelain bonded to metal restoration, what is the range of facial reduction that is considered acceptable?
1.0-1.5mm
What is the maximum thickness for the porcelain bearing surface of the metal coping for a porcelain bonded to metal restoration?
0.3mm
Mandibular incisors are the most challenging teeth in the mouth to restore using porcelain bonded to metal restorations.
TRUE
When making a gold or porcelain crown on tooth #19 the most accurate method of relating the upper and lower casts for articulation is?
by a double bite impression
What is the maximum amount of incisal reduction allowed for a porcelain bonded to metal restoration?
2.0mm
The maxillary Triad, VLC record base is cured initially for how long
2 min
The total curing time for Ortho Resin record bases is
20 minutes
RPD Direct Retainers
Cast circlet (Aker’s); embrasure clasp; cast circumferential & cast bar clasp & precision attachment
Most common type of major connectors in maxillary
Straps & plates
Indirect retainers are commonly used on tooth borne RPDs
FALSE - tooth and tissue borne/extension base RPDs
Support for the tooth borne RPD is best provided by
RESTS (tooth borne)
The principal reason we cannot “see through” enamel in the visible range is strong ____________.
light scattering
Statements about megalloy (spherical amalgam alloy)
Less mercury is required to mix it; it can become moist during placement; it is more difficult to stretch for proximal contact during condensation — FYI: Dispersalloy has zinc
When discussing cross tooth/cross arch balanced articulation, cross tooth balance refers to posterior tooth contacts that occur on which side?
working side
Which facial margin deign of the preparation is most appropriate for a porcelain bonded to metal restoration that will have a porcelain margin?
Shoulder
What is the minimal thickness of body porcelain that is necessary to achieve acceptable esthetics?
0.4mm
What is the maximum thickness for the porcelain bearing surface of the metal coping for a porcelain bonded to metal restoration?
0.3mm
Which arch does the facebow mount on the articulator?
Mandibular
How is the mandibular arch mounted on an articulator?
Wax-bite
Which class of articulator is the Hanau Articulator that is being used in the PRDS 126 laboratory?
Semi-adjustable
On which of the following teeth can the optimal amount of facial reduction most likely be achieved if you where preparing a porcelain bonded to metal restoration?
19
Hue
Color
Of the following Vita shade colors, which has the greatest value?
A1
Which of the following shades is in the yellow range?
B
Vinyl Polysiloxaine allows for easy articulation of the mandibular and maxillary cast.
FALSE
If you are preparing multiple adjacent teeth, leaving the provisional restorations connected will decrease the possibility that the provisional restorations, once cemented, will fall off.
True
The elastic bonding concept is a key factor in preserving the strength of the bond in the dentinal interdiffusion zone. What techniques listed below preserve elastic bonding?
ALL – Ramped light curing cycles of composite; Applying adequate amount of bonding resin; Applying composite with minimal C-factor profiles
6th Generation bonding systems:
Use a self etching technique which includes creating a hybrid zone that includes the smear layer
Which permanent cement could be used to cement crown temporarily?
Polycarboxylate
If you are planning to cement an all porcelain crown with a resin cement, which temporary cement could you use to cement your acrylic temporary crown while the permanent restoration is being fabricated?
TemBond NE
Comparing household porcelain to dental porcelain, dental porcelain
contains larger amounts of feldspar
Sintering of a ceramic
increases its density
In dentulous patients, masticatory forces are transmitted through the bone as _____?_____ .
tension
In edentulous patients, masticatory forces are transmitted through the bone as _____?_____ .
pressure
Tooth #18 is being prepared for a gold full veneer crown. Prior to preparing the tooth you note that the buccal cusps are out of occlusion by 0.5 mm. Having noted this, how much more will you need to reduce the buccal cusps in order to obtain ideal reduction?
1.0 mm
Tooth # 21 is being prepared for a traditional 3⁄4 partial veneer crown. Which of
the following modifications is(are) added to the preparation in order to increase the structural durability of the final restoration?
1, 2, 4 == mesial proximal groove, distal proximal groove, occlusal shoulder
