RESTS, DIRECT AND INDIRECT RETAINERS _ Removable Partial Denture MCQs
RESTS, DIRECT AND INDIRECT RETAINERS _ Removable Partial Denture MCQs
1. Terminal end of retentive arm of extra coronal retainer is placed at
a) Gingival third
b) Occlusal third
c) Middle third
d) Junction of middle & Gingival third
2. In anterior teeth ‘rests’ are ideally prepared and located on
a) Incisal edges
b) Lingual surfaces
c) Mesial surfaces
d) Distal surfaces
3. In a removable partial denture, the clasps provide retention and stability; support is provided by
a) Minor connector
b) Occlusal rests
c) Rigid portion of the class arm
d) Resilient portion of the class arm
4. Size of the bur for preparing lingual rest seat for an RPD is
a) 1/10th inch
b) 1/4th inch
c) 1/2inch
d) 1 inch
5. The terminal end of a retentive arm is optimally placed at
a) Middle of the gingival third of the clinical crown
b) Middle of the middle third of the clinical crown
c) Under the gingival sulcus in the clean area
d) Middle of occlusal third of the clinical crown
6. All of the following factors influence the flexibility of the clasp EXCEPT
a) Diameter of the clasp are
b) Length of the clasp
c) Material of the clasp
d) Tooth on which the clasp rests
7. The retentive terminal of a clasp should always point towards the
a) Facial surface
b) Occlusal surface
c) Gingiva
d) Lingual surface
8. The clasps for partial dentures should be made of
a) Gold
b) Iridioplatinum
c) Platinum
d) Silver
9. In designing the occlusal rest seat, the floor of the rest seat should be inclined towards the
a) Buccal surface
b) Centre of the tooth
c) Lingual surface
d) Marginal ridge
10. Circumferential clasp is
a) Aker’s clasp
b) Retentive arm lies at the occlusal third
c) Clasp can be easily adjusted
11. The most important mechanical property involved when a base metal partial denture clasp is adjusted is:
a) Hardness
b) Elongation
c) Elastic limit
d) Tensile strength
12. The clasp most often used on the mandibular bicuspids when the most favorable retentive undercut is on the distobuccal surface adjacent to edentulous area is
a) Ring clasp
b) Reverse loop clasp
c) Simple circlet clasp
d) Reverse approach circlet clasp
13. Indirect retention is designed to
a) Stabilize tooth borne RPD
b) Engage an undercut area of the abutment tooth
c) Resist tissue ward movement of an extension base partial denture
d) Resist dislodgement of an extension base partial denture in occlusal direction
14. Heel-raising movement of a RPD is prevented by:
a) Occlusal rests
b) Minor connector
c) Direct retainer
d) Indirect retainer
15. The function of an occlusal rest seat is
a) To resist vertical force of occlusion
b) Stabilize the denture
c) To prevent the lateral forces acting on the tooth
d) Increase retention of partial denture
16. Terminal component of clasp end is shaped as:
a) Long
b) Stop
c) Finger
d) Arm
17. Any clasp assembly should encircle at least how much of the abutment tooth?
a) 120
b) 160
c) 180
d) 360
18. Which type of R.P.D definitely requires an indirect retainer
a) Class I, II R.P.D
b) Class II, IV R.P.D
c) Class I & IV R.P.D
d) Class III & IV R.P.D
19. What would be an ideal clasp on a tooth with high survey line?
a) All wrought clasp
b) All metal clasp
c) Cast metal clasp with wrought retentive terminal
d) Wrought metal clasp with soldered noble metal retentive terminal
20. A rest seat is prepared as:
a) Spoon shaped depression with the apex towards the center of the tooth
b) Concavity with hemisphere shape
c) Elliptical shape
d) Rhomboid depression limited to enamel
21. Flexibility of clasp depends on
a) Composition & structure of material
b) Length & Cross section of clasp
c) Amount of tempering & Cold working
d) All of above
22. The function of reciprocal clasp arm is:
a) To balance the denture
b) To act as a direct retainer
c) To counteract the movement of denture which is caused during engagement of retentive arm
d) None of the above
23. Indirect retainers are most effective when:
a) They rest bilaterally on cingulum of canines
b) Rest on mesial surface of premolars with extensions on to canines
c) They rest on incisal edges of canines
d) Rest on incisal edges of lateral incisors with extensions on to central incisions
24. The means by which one part of R.P.D opposes the action of the retainer in the function is called
a) Tripoding
b) Reciprocation
c) Retention
d) Stress breaking
25. A properly designed rest on lingual surface of a canine is preferred to a rest on incisal surface because:
a) Less leverage is exerted against the tooth by lingual rest
b) Enamel is thicker on lingual surface
c) Visibility and access is better on lingual surface
d) The cingulum of canine produces a natural surface for recess
26. In full tooth borne dentures occlusal rests transmits percentage of occlusal forces to teeth:
a) 50%
b) 70%
c) 80%
d) 100%
27. The main action of the reciprocating arm is
a) Reciprocates the action of the retentive arm
b) Reciprocation of vertical displacement
c) To provide stability to the denture
d) None of the above
28. Indirect retainers in R.P.D are placed:
a) In line with the direct retainers
b) Are not necessary if direct retainers are given
c) Opposite side of the fulcrum line of the denture base and away from the direct retainers.
d) Opposite side of the fulcrum line of the denture base and close to the direct retainers.
31. Intracoronal retainer placed in the abutment teeth has the following disadvantage
a) It is unaesthetic
b) They cannot provide support and stability
c) Difficult laboratory procedures
d) Difficult to repair and replace
32. For the preparation of the rest seat in the marginal ridge of a molar tooth which is reduced by 2mm to achieve the correct width of the rest seat. The marginal ridge is then rounded in order to:
a) Reduce the chances of fracture of the metal rest
b) Decrease food impaction
c) For better distribution of the vertical load
d) Better clasp retention
33. Indirect retainers are situated:
a) As far anteriorly from the fulcrum line
b) As close to the fulcrum line
c) At the canine region
d) At the mesial marginal ridge of the premolars in the class I case
34. Bracing of RPD framework can be best obtained by:
a) Rigid reciprocal arm of the clasp
b) Rigid reciprocal arm and body of clasp
c) Rigid reciprocal arm and flexible part of the retentive arm of the clasp
d) None of the above
35. Indirect retainers of a partial denture:
a) Engages undercut areas
b) Most effective when close to direct retainers
c) Must be constructed with flexible materials like plastics.
d) Should resist rotatory forces about a fulcrum
36. Which of the following is an example of push back type clasp
a) Circumferential clasp
b) Bar clasp
c) Embrasure clasp
d) Indirect retainer
37. The floor of the occlusal rest is:
a) Ledge shaped
b) Half pear shaped
c) Spoon shaped
d) Half moon shaped
38. Internal attachments for a partial denture is used:
a) When restoring a palatal cleft
b) When abutment tooth has dental caries
c) When there is difficult in getting clasp retention
d) When restoring lost vertical dimension
39. A complete clasp assembly consists of a
a) Retentive arm and a reciprocal arm
b) Circumferential arm and a bar-type arm
c) Proximal plate and a retentive arm
d) Retentive arm, an occlusal rest, and reciprocating elements.
40. The primary indication for precision attachment of RPD when the abutment teeth are well supported when the patient is:
a) Esthetically concerned
b) Abutment teeth require restoration
c) No posterior abutment teeth are present
d) When teeth are present on both the ends of the edentulous area
41. RPI stands for:
a) Occlusal rest, proximal plate, I bar,
b) Cingulum rest, proximal plate, I bar
c) Rest, proximal guide plane, I bar.
d) Rest, proximal plate, indirect retainer.
42. Failure of partial dentures due to poor clasp design can best be avoided by:
a) Using stress breakers
b) Using bar-type clasps
c) Altering tooth contours
d) Clasping only those teeth with fairly long crowns and normal bone support
43. Combination clasp consist of
a) Wrought wire reciprocal arm and cast retentive arm
b) Wrought retentive arm and cast reciprocal arm
c) Wrought reciprocal and wrought retentive arm
d) Cast retentive and cast reciprocal arm
44. Indirect retention for a partial denture is achieved from which one of the following?
a) Lingual bar
b) Lingual plate
c) Palatal bar
d) Double palatal bar
45. Which statement is not an advantage for a particular clasp ? The clasp
a) Should be flexible enough for the purpose of its use
b) Should cover a maximum of tooth surface
c) Terminal retentive arm should be able to be adjusted
d) Should be as inconspicuous as possible
46. An extra coronal retainer should bear
a) Passive relationship to the tooth
b) Active relationship to the tooth
c) Active relationship to the tooth except when dislodging force is used
d) Passive relationship to the tooth except when a dislodging force is used
47. Which of the following statement is false
a) Each retentive arm of a clasp should be opposed by a reciprocal (bracing) arm
b) The path of escapement of a retentive clasp should be parallel to the path of removal of the RPD
c) The amount of retention should be the minimum amount necessary to resist reasonable dislodging
d) None of the above
48. A ring clasp is used
a) In Kennedy class I case
b) Always with a supporting strut
c) On tilted molars
d) Both B and C
49. The ideal clasp to use for its retentive and bracing qualities in all tooth supported Kennedy class III is
a) Back action clasp
b) Circumferential clasp
c) Bar clasp
d) Ring clasp
50. Multiple clasping is used when
a) The remaining natural teeth are not periodontally strong enough to act as separate abutments
b) More retention is necessary
c) The dentist wants an expensive partial denture
d) The dentist tries to conserve tooth structure
51. In order to achieve maximum flexibility a clasp arm must be
a) Cast chrome
b) Half round in shape
c) Round in shape
d) None of the above
52. A multiple clasp is
a) Two bar clasp joined
b) Two circumferential clasp with one minor connector
c) Two circumferential clasps opposing one another with two minor connectors and joined by their reciprocal arms
d) Many clasp joined together
53. The clasp of choice to be used in a Kennedy class I case for the distal abutment teeth
a) Circumferential cast clasp
b) Circumferential combination clasp
c) Bar clasp with mesial undercuts
d) Back action clasp with distal rest
54. Half and half clasp is best used on
a) Tilted molars
b) Distal abutments in a Kennedy class I case
c) Isolated teeth
d) Supra erupted teeth
55. The advantage of combination clasp is
a) Its flexibility
b) Esthetically it is more pleasing than other clasps
c) It covers a minimum of tooth structural because of line contact
d) All of the above
56. The disadvantage of circumferential clasp is
a) More tooth surface is covered than with a bar clasp arm because of its occlusal direction of approach
b) More metal display than with bar clasp arm
c) Its half round form prevents edgewise adjustment
d) All of the above
57. Contraindication for using a bar-type direct retainer is:
a) Usable distributed on terminal abutments
b) When esthetics demand less display of metal
c) When a large tissue undercut is present
d) When a push type of retention is needed
58. The angle between occlusal rest and the vertical minor connector from which it originates is
a) 90 degrees
b) 100 degrees
c) 120 degrees
d) Less than 90 degrees
59. Rests may be placed upon
a) Sound enamel
b) Cast restorations
c) Silver amalgam
d) All of the above
60. Possible movement(s) of a distal extension partial denture could be
a) Rotation around a fulcrum line passing through the two principal occlusal rests
b) Rotation around a longitudinal axis formed by the crest of the residual ridge
c) Rotation around a vertical axis located near the center of the arch
d) All of the above
61. Kroll designed
a) RPI clasp
b) Bar clasp
c) Circumferential clasp
d) Altered clasp
62. A wrought wire clasp is considered most effective in Kennedy class
a) III cases for periodontally weakened abutment teeth
b) I cases for periodontally weakened abutment teeth
c) II cases for the non edentulous side
d) IV cases with periodontally weakened teeth
63. Which of the following is the primary reason for using plastic teeth in a removable partial denture? Plastic teeth are:
a) Resistant to wear
b) Resistant to stains
c) Esthetically acceptable
d) Retained well in acrylic resin
64. Indirect retainers in bilateral distal extension base removable partial dentures are based on:
a) Class I lever principle
b) Class II lever principle
c) Class III lever principle
d) Combination of more than one of the above
65. Back action clasp is a modification of
a) Embrasure clasp
b) Half & half clasp
c) Reverse action clasp
d) Ring clasp
66. Which component of a removable partial denture used to retain or prevent dislodgement?
a) Indirect retainer
b) Rest
c) Minor connector
d) Direct retainer
67. A rigid reciprocal arm of a clasp may also act as:
a) Direct retainer
b) An auxiliary indirect retainer
c) Major connector
d) Minor connector
68. Reciprocal arm serves mainly to:
a) To give flexibility
b) Give indirect retention
c) Counteract the forces of retentive arm
d) To give support
69. Which of the following is not a disadvantage of combination clasp in comparison to circumferential clasp?
a) It is easily distorted by handling of the patient
b) More tooth surface is covered than with a bar clasp because of its occlusal direction of approach.
c) Avoid the use of extracoronal and occlusal record
d) It can flex in any spatial plane
70. Which among the following has great flexibility:
a) Cast circumferential clasp arm
b) Wrought circumferential clasp arm
c) Cast bar clasp arm
d) Wrought bar clasp arm
71. A circumferential clasp arm:
a) Originates above the height of contour
b) Originates below the height of contour
c) Traverses soft tissue
d) Approaches undercut from gingival direction
72. The direct retainer of choice when the principle abutment tooth has lost its periodontal support is:
a) Embrasure clasp
b) Ring clasp
c) Multiple circlet clasp
d) Onlay clasp
73. Indirect Retainer is placed:
a) Near direct retainer
b) As far as possible from fulcrum line
c) Near fulcrum line
d) Near edentulous area
74. A cantilever design is a lever of
a) Class I
b) Class II
c) Class III
d) Class IV
75. Compared to a cast circumferential clasp, the main disadvantage of a combination clasp is that, it?
a) Can flex in all spatial planes
b) Is more prone to breakage and damage
c) makes greater surface contact with the tooth
d) Is less acceptable esthetically
76. Most common reason for failure of rest seat in RPD is
a) Improper rest seat preparation
b) Contaminated metal
c) Distorted occlusal rest
d) Excessive occlusal forces
77. For strength and rigidity, the vertical height of a finished lingual bar should be at least
a) 6mm
b) 7mm
c) 4mm
d) 5mm
78. In a tooth supported partial denture movement of the base towards the edentulous ridge is prevented primary by
a) Clasps on abutment teeth
b) Rests on abutment teeth
c) Indirect retainer on abutment teeth
d) Minor connector on abutment teeth
79. Secondary retention for a removable partial denture is provided by
a) The indirect retainer
b) The direct retainer
c) Intimate contact between the denture bases and the underlying tissues
d) Direct and indirect retainers
80. Internal occlusal rest provided in partial denture does not provide:
a) Horizontal stabilization
b) Retention
c) Vertical stop
d) Occlusal support
81. Advantages of wrought gold alloy clasp wires over cast gold clasps of the same cross sectional area are
a) Coarser grain
b) Higher yield strength
c) Greater flexibility
d) More accurate adaptation to the tooth
82. The rest seat for a lingual rest is
a) Triangular shaped
b) Round shaped
c) V-Shaped
d) Oval Shaped
83. Auxiliary rest are
a) Direct retainer
b) Indirect retainer
c) All of the above
d) None of the above
84. Clasp used in distobuccal undercut of distal extension removable partial denture are all expect?
a) Combination clasp
b) Embrasure clasp
c) Circumferential clasp
d) Reverse circlet clasp
85. Retentive clasp arms should be placed on each abutment tooth such that
a) The retentive terminals are below the height of contact
b) There is a frictional fit on the surface of the abutment
c) They are in approximately the same degree of undercut
d) The retentive terminals are above the height of contour
86. For locating clasp patterns, which block out is used?
a) Parallel block out
b) Shaped block out
c) Arbitrary block out
d) Relief