PRINCIPLES OF REMOVABLE PARTIAL DENTURE DESIGN

Question 1

T/ F

the strategy of selecting component parts for a partial denture to help control the movement of the prosthesis under functional load has been
highlighted as as method to consider for
logical partial denture design

Answer 1

T

Question 2

Who introduced 5 basic principles in designing of removable partial denture?

Answer 2

COLONEL ARTHUR H. SCHMIDT (1953)

Question 3

5 basic principles in designing of removable partial denture:

Answer 3

(1) Dentist must have a working knowledge of both the mechanical and biological factors included in RPD design and construction

(2) Any plan of restoration must be based on complete examination and diagnosis of individual patient

(3) The dentist not the technician should correlate the pertinent factors and recommend a proper plan of treatment

(4) A RPD should restore form and function without injury to the tissue

(5) A RPD is a form of treatment not a care

Question 4

tooth-supported, or Class III, removable partial denture, like fixed partial denture, is supported by ___

Answer 4

abutments

Question 5

T/ F

Classes I, II, and IV removable partial dentures are subjected to greater stresses because their support is a combination of tooth and soft tissue

Answer 5

T

Question 6

a removable partial denture in the mouth can perform the
action of two simple machines, the ___&___

Answer 6

lever and the inclined plane

Question 7

if the lever rests against its ___ and a weight is applied at another point, rotation or movement will occur around the
support

Answer 7

support

(the support is known as the fulcrum and movement takes
place around the fulcrum)

Question 8

fulcrum is in center

→ resistance is at one end

A. First-Class
B. Second-Class
C. Third-Class

Answer 8

A

Question 9

→ effort or force is at opposite end
→ most efficient and easily controlled lever

A. First-Class
B. Second-Class
C. Third-Class

Answer 9

A

Question 10

→ fulcrum at one end
→ effort at opposite end

A. First-Class
B. Second-Class
C. Third-Class

Answer 10

B

Question 11

→ resistance in center
→ seen as indirect retention in removable
partial dentures

A. First-Class
B. Second-Class
C. Third-Class

Answer 11

B

Question 12

→ fulcrum at one end
→ resistance at opposite

A. First-Class
B. Second-Class
C. Third-Class

Answer 12

C

Question 13

→ effort in center
→ not encountered in partial dentures

A. First-Class
B. Second-Class
C. Third-Class

Answer 13

C

Question 14

the ___ is the other simple machine to be concerned with

o forces against the inclined plane may result in deflection of that which is applying the force or may result in movement to the inclined plane

o neither of these results is desirable

Answer 14

inclined plane

Question 15

is in distal extension removable partial dentures that the type
of prosthesis controlling stress is important

Answer 15

PROSTHESIS SUPPORT

Question 16

T/f

the all-tooth supported partial denture is mostly subjected to
induced stresses, because leverage-type forces are not involved and there are no fulcrums around which the partial denture may rotate

Answer 16

F

the all-tooth supported partial denture is RARELY subjected to
induced stresses, because leverage-type forces are not involved and there are no fulcrums around which the partial denture may rotate

Question 17

T/f

inclined planes are also not a factor when the partial denture is tooth supported

Answer 17

T

Question 18

T/F

the distal extension partial denture, on the other hand, is subjected to rotation around three principal fulcrums

Answer 18

T

Question 19

T/f

horizontal fulcrum line passing between two principal
abutment teeth controls rotational motion of denture toward or away from supporting ridge

Answer 19

T

Question 20

________ extends from occlusal rest on terminal abutment posteriorly along crest of residual ridge; this fulcrum controls rocking, or side-to-side, movement that takes place over crest of ridge; in a Class I arch there are two such fulcrums

Answer 20

second rotational fulcrum

Question 21

third fulcrum is ____ and is located in midline lingual to anterior teeth; it controls movement of denture in horizontal plane

Answer 21

vertical

Question 22

T/ f

a modified T bar or I bar engaging the distobuccal
retentive area results in action similar to second class lever; when downward pressure is applied to partial denture, the clasp tip will also have downward movement thereby minimizing lateral stress on the abutment tooth

Answer 22

T

Question 23

T/ F

Intracoronal retainers change the contour of abutment teeth

Answer 23

F

extracoronal retainers change the contour of abutment teeth

Question 24

T/F

lingual and palatal major connectors must be rigid to transmit lateral stresses to other parts of the partial denture

Answer 24

T

Question 25

T/F

lingual and palatal major connectors must be rigid to transmit lateral stresses to other parts of the partial denture

Answer 25

T

Question 26

T/f

The longer the edentulous area covered by the denture base, the greater the potential level action on the abutment teeth

Answer 26

T

Question 27

T/f

Flat ridge will provide good support, poor stability

Answer 27

T

Question 28

T/f

Sharp spiny ridge will provide poor support, poor to fair
stability

Answer 28

T

Question 29

T/f

Displaceable tissue on ridge will provide poor support and
poor stability

Answer 29

T

Question 30

elastic impression materials use for IMPRESSION REGISTRATION

Answer 30

*irreversible hydrocolloid (alginate)
*mercaptan rubber base (thiokol)
*silicone impression materials (both condensation and addition reaction)
* polyethers

Question 31

T/f

The supporting form of the soft tissue underlying the distal
extension base of the partial denture should be recorded so that firm areas are used as primary stress-bearing areas and readily displaceable tissues are not overloaded

Answer 31

T

Question 32

T/f

no single impression material can satisfactorily fulfill both of the previously mentioned requirements
→ recording the anatomic form of both teeth and supporting tissue will result in inadequate support for the distal extension base this is because the cast will ot represent the optimum coordinating forms, which necessitates that the ridge be related to the teeth in a supportive form

Answer 32

T

Question 33

T/f

a fifth point of difference between the two main types of removable partial denture lies in their requirements for direct retention

Answer 33

T

Question 34

arising from the body fo the clasp and approaching the undercut from an occlusal direction

Answer 34

Circumferential Type

Question 35

arising from the base of the denture and approaching the undercut area from a gingival direction

Answer 35

Bar Type

Question 36

T/ f

in the combination tooth- and tissue-supported removable partial dentures, because of this tissue ward movement, those elements of a clasp that lie in an undercut area mesial to the fulcrum for a distal extension (as is often seen with a distal rest) must be able to flex sufficiently to dissipate stresses that otherwise would be transmitted directly to the abutment tooth as leverage

Answer 36

T

Question 37

produced on a cast by a surveyor making the greatest prominent of contour in relation to the planned path of placement of a restoration (GPT 7)

Answer 37

SURVEY LINES

Question 38

marks the height of contour of the tooth

Answer 38

SURVEY LINES

Question 39

Blatterfein divided the buccal and lingual surfaces in to two halves and described them as:

Answer 39

Near Zone

Far Zone

Question 40

area closer to the edentulous space

Answer 40

Near Zone

Question 41

area away from the edentulous space

Answer 41

Far Zone

Question 42

survey lines can be classified as:

Answer 42

A. High Survey Line

B. Medium Survey Line

C. Low Survey Line

D. Diagonal Survey Line

Question 43

→ line passes from the occlusal third in the near zone to the occlusal third in the far zone
→ undercut will be deep

A. High Survey Line

B. Medium Survey Line

C. Low Survey Line

D. Diagonal Survey Line

Answer 43

A

Question 44

a wrought wire clasp which is more flexible should be used

A. High Survey Line

B. Medium Survey Line

C. Low Survey Line

D. Diagonal Survey Line

Answer 44

A

Question 45

→ line passes from the occlusal third in the near zone to the middle third in the far zone
→ aker’s or roach clasp is used

A. High Survey Line

B. Medium Survey Line

C. Low Survey Line

D. Diagonal Survey Line

Answer 45

B

Question 46

→ closer to the cervical third of the tooth in both near and far zone
→ a modified t-clasp is used

A. High Survey Line

B. Medium Survey Line

C. Low Survey Line

D. Diagonal Survey Line

Answer 46

C

Question 47

runs from occlusal third in the near zone to cervical third of far zone

A. High Survey Line

B. Medium Survey Line

C. Low Survey Line

D. Diagonal Survey Line

Answer 47

D

Question 48

a reverse circlet clasp is used

A. High Survey Line

B. Medium Survey Line

C. Low Survey Line

D. Diagonal Survey Line

Answer 48

D

Question 49

originating from a distal occlusal rest on the terminal abutment tooth and engaging a mesio-buccal retentive undercut should not be used on a distal extension removable partial denture

Answer 49

CIRCUMFERENTIAL CAST CLASP

Question 50

→ the terminal of this clasp reacts to movement of the denture base toward the tissue by placing a distal tipping, or torquing, force on the abutment tooth
→ this particular force is the most destructive force a retentive clasp can exert; this clasping concept must be avoided at all costs

Answer 50

CIRCUMFERENTIAL CAST CLASP

Question 51

approaching a distobuccal undercut from mesial occlusal surface, may be acceptable for a distal extension partial denture. As the denture base moves toward the tissue, the retentive clasp tip will tend to move into an area of greater undercut (arrow). This action releases torquing forces that can damage an abutment tooth.

Answer 51

reverse circlet clasp

Question 52

used on the terminal abutment tooth on a distal extension partial denture when the retentive undercut is located on the distobuccal surface

Answer 52

vertical projection, or bar, clasp

Question 53

as the denture base is loaded toward the tissue, the retentive tip of the T-clasp rotates gingivally to release the stress being transmitted to the abutment tooth

Answer 53

VERTICAL PROJECTION, OR BAR, CLASP

Question 54

→ it is never indicated when the tooth has a mesiobuccal undercut
→ the bar clasp functions in a manner similar to the reverse
circumferential clasp

Answer 54

VERTICAL PROJECTION, OR BAR, CLASP

Question 55

releases torsional stress on the terminal abutment tooth.

Answer 55

The vertical projection T-clasp

Question 56

This releasing action is accomplished when the retentive clasp tip rotates gingivally into a greater undercut as tissueward forces are applied to the denture base (arrows). Rotation takes place around distal occlusal rest.

Answer 56

vertical projection T-clasp

Question 57

(VERTICAL PROJECTION, OR BAR, CLASP )

→ one school of thought on the philosophy of removable partial denture design has advocated omitting the _____ occlusal rest from the terminal abutment in favor of a ___ rest when a bar clasp is used
→ advantage claimed for moving the occlusal rest more ___ is that the lever arm (the distance from the rest to the denture base) is ___, which causes the force directed toward the residual ridge to be more vertical and thus, better tolerated by the ridge

Answer 57

distal, mesial

anteriorly, increased

Question 58

(VERTICAL PROJECTION, OR BAR, CLASP )

One advantage claimed for eliminating distal occlusal rest (A) and placing a mesial rest more anteriorly (B) is that lever arm, represented by ____ from rest to denture base, is increased.

Answer 58

distance

Question 59

(VERTICAL PROJECTION, OR BAR, CLASP)

A ___ force is better tolerated by ridge than is a ___ oblique force

Answer 59

vertical, horizontal

Question 60

when a mesiobuccal undercut exists on an abutment tooth adjacent to a distal extension edentulous ridge, the combination clasp can be employed to reduce the stress transmitted to the abutment tooth

Answer 60

COMBINATION CLASP

Question 61

wrought alloy wire, by virtue of its internal structure, is more flexible than a cast clasp

Answer 61

COMBINATION CLASP

Question 62

can flex in any spatial plane, whereas a cast clasp flexes in the horizontal plane only

Answer 62

COMBINATION CLASP

Question 63

the wrought wire retentive arm has a stress-breaking action that can absorb torsional stress in both the vertical and horizontal planes

Answer 63

COMBINATION CLASP

Question 64

how the tooth has responded to
previous stress)

Answer 64

bone index area

Question 65

in a tooth- and tissue-supported partial denture, consideration must be given to:

Answer 65

• the quality of the residual ridge, which includes contour, quality of the supporting bone and quality of the supporting mucosa
• the extent to which the residual ridge will be covered by the denture base
• the type and accuracy of the impression registration
• the accuracy of the denture base
• the design characteristics of the component parts
  of the partial denture framework
• the anticipated occlusal load

Question 66

in an entirely tooth-supported partial denture, the potential
support an abutment tooth can provide, consideration should be given to:

Answer 66

• periodontal health
• crown and root morphologies
• crown-to-root ratio
• bone index area (how the tooth has responded to
  previous stress)
• location of the tooth in the arch
• relationship of the tooth to other support units
  (length of edentulous span
• the opposing dentition

Question 67

T/f

major connectors must be rigid so that forces applied to
any portion of the denture can be effectively distributed to
the supporting structures

Answer 67

T

Question 68

T/f

minor connectors arising from the major connector make it
possible to transfer functional stress to each abutment tooth through its connection to the corresponding rest and also to transfer the effect of the retainers, rests, and stabilizing components to the remainder of the denture and throughout the dental arch

Answer 68

T

Question 69

T/f

retention is accomplished by mechanical retaining elements (clasps)

Answer 69

T

Question 70

retention is accomplished by mechanical retaining elements (clasps), the key to selecting a successful clasp design for any given situation is to choose one that will:

Answer 70

• avoid direct transmission of tipping or torquing forces to the abutment
• accommodate the basic principles of clasp design
• provide retention against reasonable dislodging
  forces
• be compatible with undercut location, tissue
  contour, and esthetic desires of the patient

Question 71

T/F

the fourth step is to connect the retention units to the support
units

o if direct and indirect retainers are to function as designed,
each must be rigidly attached to the major connector

Answer 71

T

Question 72

T/f

the fifth and last step in this systematic approach to design is to outline and join the edentulous area to the already established design components

Answer 72

T

Question 73

ESSENTIALS OF PARTIAL DENTURE DESIGN

determine how the partial denture is to be supported:

A, 1st
B. 2nd
C. 3rd
D. 4th
E. 5th

Answer 73

A

Question 74

ESSENTIALS OF PARTIAL DENTURE DESIGN

systematically developing the design for any removable partial denture is to connect the tooth and tissue support units

A, 1st
B. 2nd
C. 3rd
D. 4th
E. 5th

Answer 74

B

Question 75

ESSENTIALS OF PARTIAL DENTURE DESIGN

the third step is to determine how the removable partial denture is to be retained

A, 1st
B. 2nd
C. 3rd
D. 4th
E. 5th

Answer 75

C

Question 76

ESSENTIALS OF PARTIAL DENTURE DESIGN

is to connect the retention units to the support
units

A, 1st
B. 2nd
C. 3rd
D. 4th
E. 5th

Answer 76

D

Question 77

ESSENTIALS OF PARTIAL DENTURE DESIGN

systematic approach to design is to outline and join the edentulous area to the already established design components

A, 1st
B. 2nd
C. 3rd
D. 4th
E. 5th

Answer 77

E

Question 78

T/f

to secure the maximum possible retention through the use of the forces of adhesion and cohesion, the denture base should cover the maximum area of available support and must be accurately adapted to the underlying mucosa

Answer 78

T

Question 79

T/f

To enhance the quality of retention through adhesion and cohesion, the denture base must fit edentulous ridge accurately and must cover the maximum area of available support.

Answer 79

T

Question 80

the partial denture should be designed so that guide planes are created on as many teeth as possible

Answer 80

FRICTIONAL CONTROL

Question 81

term guiding plane is defined as two or more parallel, vertical surfaces of abutment teeth, so shaped to direct a prosthesis during placement and removal

Answer 81

FRICTIONAL CONTROL

Question 82

Development of guide planes on proximal surfaces of teeth adjacent to edentulous spaces will increase retention of partial denture by ____. These guide planes may be created in enamel surfaces.

Answer 82

frictional contact

Question 83

is indicated most often for Class III arches particularly when there is a modification space on the opposite side of the arch

Answer 83

QUADRILATERAL CONFIGURATION

Question 84

a retentive clasp should be positioned on each abutment tooth adjacent to the edentulous spaces

o this results in the denture being confined within the outline
of the four clasps and leverage on the denture is effectively neutralized

A. QUADRILATERAL CONFIGURATION
B. TRIPOD CONFIGURATION
C. BILATERAL CONFIGURATION

Answer 84

QUADRILATERAL CONFIGURATION

Question 85

is used primarily for Class II arches

o if there is a modification space on the edentulous side, the teeth anterior and posterior to the space are clasped

A. QUADRILATERAL CONFIGURATION
B. TRIPOD CONFIGURATION
C. BILATERAL CONFIGURATION

Answer 85

B

Question 86

this design is not as effective as the quadrilateral configuration, but is most effective in neutralizing leverage in the Class II situation

A. QUADRILATERAL CONFIGURATION
B. TRIPOD CONFIGURATION
C. BILATERAL CONFIGURATION

Answer 86

B

Question 87

most removable partial dentures fall into the bilateral distal extension group or Class I

A. QUADRILATERAL CONFIGURATION
B. TRIPOD CONFIGURATION
C. BILATERAL CONFIGURATION

Answer 87

C

Question 88

the single retentive clasp on each side of the arch should be located near the center of the dental arch or denture bearing area

A. QUADRILATERAL CONFIGURATION
B. TRIPOD CONFIGURATION
C. BILATERAL CONFIGURATION

Answer 88

C

Question 89

the clasps exert little neutralizing effect on the leverage-induced stresses generated by the denture base

A. QUADRILATERAL CONFIGURATION
B. TRIPOD CONFIGURATION
C. BILATERAL CONFIGURATION

Answer 89

C

Question 90

part of the partial removable denture prosthesis that joins the components of one side of the arch to those on the opposite sid

A. MAJOR CONNECTORS
B. MINOR CONNECTORS

Answer 90

A

Question 91

should be rigid necessary to provide proper distribution of forces to and from the supporting components

A. MAJOR CONNECTORS
B. MINOR CONNECTORS

Answer 91

A

Question 92

must be supported by rests at each of anterior span

A. MAJOR CONNECTORS
B. MINOR CONNECTORS

Answer 92

A

Question 93

T/f

In the mandibular arch, the lingual plate major connector that is properly supported by rests can aid in the distribution of functional stresses to the remaining teeth.

Answer 93

T

Question 94

T/f

In the maxillary arch, the use of a broad palatal major connector that contacts several of the remaining natural through lingual plating can distribute stress over a large area

Answer 94

T

Question 95

T/f

In the maxillary arch, the use of a broad palatal major connector that contacts several of the remaining natural through lingual plating can distribute stress over a large area

Answer 95

T

Question 96

the connecting link between the major connector or base of a partial removable denture prosthesis and the other units of the prosthesis such as the clasp assembly, indirect retainers, occlusal rests, or cingulum rests

A. MAJOR CONNECTORS
B. MINOR CONNECTORS

Answer 96

B

Question 97

this close metal-to-enamel contact serves two purposes:
o offers horizontal stability to the partial denture against lateral forces on the prosthesis; the tooth with its supporting
bone helps dissipate these displacing stresses

A. MAJOR CONNECTORS
B. MINOR CONNECTORS

Answer 97

B

Question 98

through the contact of the minor connector and the abutment tooth, the tooth receives stabilization against ____ stresses

Answer 98

lateral

Question 99

component of a removable dental prosthesis used to retain and prevent dislodgement, consisting of a clasp assembly and precision attachment

Answer 99

Direct Retainer

Question 100

the part of the removable dental prosthesis that acts as a direct retainer and/or a stabilizer for a prosthesis by partially encompassing or contacting an abutment tooth

Answer 100

Clasp Assembly

Question 101

an interlocking device, one component of which is fixed to an abutment or abutments and the other is integrated to a removable dental prosthesis in order to stabilize and/or to retain it

Answer 101

Precision Attachment

Question 102

retain the prosthesis against reasonable dislodging
forces without damage to the abutment teeth

A. TOOTH-SUPPORTED PARTIAL DENTURES
B. DISTAL EXTENSION PARTIAL DENTURES

Answer 102

A

Question 103

to aid in resisting any tendency of the denture to be
displaced in a horizontal plane

A. TOOTH-SUPPORTED PARTIAL DENTURES
B. DISTAL EXTENSION PARTIAL DENTURES

Answer 103

A

Question 104

→ the prosthesis cannot move tissueward as the rest supports the
retentive components of the clasp assembly
→ there should be no movement away from the tissue and
therefore, no rotation about a fulcrum because a direct retainer
secures the retentive component

A. TOOTH-SUPPORTED PARTIAL DENTURES
B. DISTAL EXTENSION PARTIAL DENTURES

Answer 104

A

Question 105

→ the clasp retainer must not impinge on gingival tissue and must
not exert excessive torque on the abutment tooth during
placement and removal
→ it must be located the least distance into the tooth undercut for
adequate retention and it must be designed with a minimum of
bulk and tooth contact

A. TOOTH-SUPPORTED PARTIAL DENTURES
B. DISTAL EXTENSION PARTIAL DENTURES

Answer 105

A

Question 106

→ the bar clasp arm should be used only when the area for
retention lies close to the gingival margin of the tooth
→ with an excessive tissue undercut, recontouring the abutment and
using some type of circumferential direct retainer is advisable

A. TOOTH-SUPPORTED PARTIAL DENTURES
B. DISTAL EXTENSION PARTIAL DENTURES

Answer 106

A

Question 107

____ (frictional) retainers are ideal for tooth-supported
restorations and offer esthetic advantages that are not possible
with extracoronal (clasp) retainers

Answer 107

intracoronal

Question 108

____ (frictional) retainers are ideal for tooth-supported
restorations and offer esthetic advantages that are not possible
with extracoronal (clasp) retainers

Answer 108

intracoronal

Question 109

the retainer should retain the prosthesis and also be able to flex or disengage when the denture base moves tissueward under function; thus, the retainer may act as a stress-breaker

A. TOOTH-SUPPORTED PARTIAL DENTURES
B. DISTAL EXTENSION PARTIAL DENTURES

Answer 109

B

Question 110

→ the clasp arm must be freely flexible in any direction, as dictated by the stresses applied
→ bound, tapered clasp forms offer advantages of greater and more universal flexibility, less tooth contact, and better esthetics

A. TOOTH-SUPPORTED PARTIAL DENTURES
B. DISTAL EXTENSION PARTIAL DENTURES

Answer 110

B

Question 111

explained stress breakers which automatically return the saddle to rest position following displacement

Answer 111

ALLISON G. JAMES (1955)

Question 112

basic principle involved is that portion of appliance directly attached to the abutment teeth, the anterior part of palatal casting shall be rigid, and with __ motion possible allowed
between it and the abutment

Answer 112

minimum

Question 113

the ___ will be attached to this rigid portion by a narrow
isthmus in the saddle casting as close as feasible to the midline of the palatal appliance

Answer 113

saddles

Question 114

components of the partial removable dental prosthesis that assists the direct retainers in preventing displacement of the distal extension denture by functioning through lever action on the opposite side of the fulcrum line when the denture base moves away from the tissues in pure rotation around the fulcrum line

Answer 114

INDIRECT RETAINERS

Question 115

→ it must be placed as far anterior from the fulcrum line
→ it must be placed on a rest seat prepared on an abutment tooth
that is capable of withstanding the forces placed on it

Answer 115

INDIRECT RETAINERS

Question 116

cannot function effectively on an inclined tooth surface, nor on a single weak incisor tooth; either a canine or premolar tooth
should be used for the support of

Answer 116

indirect retainer

Question 117

function:
o restrict movement of a distal extension base away from the basal seat tissue

o support for major connectors

Answer 117

INDIRECT RETAINERS

Question 118

when the edentulous span is too large to ensure adequate support from the adjacent teeth, an ________ may be attached to the adjacent abutment teeth in such a manner that fixed splinting of the abutment teeth results, with a smooth, contoured bar resting lightly on the gingival tissue to support the removable partial denture

Answer 118

anterior splint bar

Question 119

___ surfaces are minimally contacted by rounded form of lower portion of bar. Anterior and posterior slopes of splint bar must be compatible with path of placement of denture.

Answer 119

Tissue

Question 120

differs from the splint bar in that the ____ provides both support and retention from the connecting bar

Answer 120

internal clip attachment

Question 121

→ every consideration should be directed to preventing the need for a distal extension removable partial denture
→ in many instances, it is possible to salvage the roots and a portion of the crown of a badly broken-down molar through endodontic treatment

Answer 121

OVERLAY ABUTMENT AS SUPPORT FOR A DENTURE BASE

Question 122

→ a ______ is a removable partial denture in which the framework is designed and fabricated in separate parts
→ the tooth support and tissue supported components are individually fabricated, and the two are joined with a high impact acrylic resin to become a single, rigid functioning unit

Answer 122

component partial