IMPORTANT VIVA QUESTIONS PROSTHODONTICS

April 16, 2018
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COMMON VIVA QUESTION:

Q76. What is RPD?

Ans. RPD is defined as any prosthesis that replaces some teeth in a partially dentate arch.It can be removed from the mouth and replaced at will-also called partial removable dental prosthesis.

Q78. What are the components of RPD?

Ans. The components of removable partial denture are:

  1. Connectors –  (a) major                      (b) minor
  1. Retainers –     (a) direct                       (b) indirect
  1. Rests
  2. Denture base
  3. Artificial teeth

Q79. What is a major connector?

Ans. The part of a partial removable dental prosthesis that joins the components on one side of the arch to the components on opposite side.

Q80. What are the functions of a major connector?

Ans. The functions of major connector are:

  1. It connects the components on one side of the arch to the opposite side of the arch
  2. It provides the cross arch stabilization

Q81. What are the types of maxillary major connectors?

Ans. The types of  maxillary major connector are:

  1. Single palatal strap
  2. Combination anterior and posterior strap type
  3. Complete palatal plate type connector
  4. Horseshoe or U- shaped palatal connector
  5. Single palatal bar
  6. Closed horseshoe or anteroposterior palatal bars

Q81. What are the types of mandibular major connectors?

Ans. The types of the mandibular major connector are:

  1. Lingual bar
  2. Labial bar
  3. Double lingual bar/ kennedy bar
  4. Lingual plate

Q82. What is a minor connector?

Ans. The connecting link between the major connector or base of partial removable dental prosthesis and other components of the prosthesis, such as the clasp assembly, indirect retainers, occlusal rests, or cingulum rests.

Q83. What are types of minor connectors?

Ans. There are four types of minor connector. They are:

  1. Connector that joins the clasp assembly to the major connector
  2. Connector that joins indirect retainers or auxiliary rests to the major connectors
  3. Connector that joins the denture base to the major connector
  4. Connector that serve as an approach arm for a vertical projection or bar type clasp

Q84. What are the types of minor connectors that joins the denture base to the major connector?
Ans. There are three types of minor connectors that joins the denture base to the major connector. They are:

  1. Ladder or lattice work
  2. Nail head or bead
  3. Meshwork

Q85. What is direct retainer?

Ans. The direct retainers are of two types?

  1. Extracoronal retainers or the clasp type
  2. Occlusally approaching, e.g. circumferential or Akers clasp
  3. Gingivally approaching, e.g. bar or Roach clasp
  4. Intracoronal retainers or the attachments

Q86. What are the parts of clasp?

Ans. The parts of the clasp are:

  1. Rest
  2. Body
  3. Shoulder
  4. Reciprocal clasp arm
  5. Retentive arm
  6. Retentive terminal
  7. Minor connector
  8. Approach arm

Q87. What are the requirements of a clasp design?

Ans. The basic requirements of clasp design are:

  1. Retention
  2. Support
  3. Stability
  4. Reciprocation
  5. Encirclement
  6. Passivity

Q88. What is the other name for reciprocal arm?

Ans. Reciprocal arm is also called bracing arm or stabilizing arm.

Q89. What is a combination clasp?

Ans. The combination clasp consists of the cast reciprocal arm and wrought retentive arm.Combination clasp is usually indicated in greater or a deeper undercut area where more flexibility of the retentive clasp arm is required.

Q90. Which is the only component of the clasp which is placed below the height of the contour?

Ans.The retentive terminal tip is placed below the height of contour of the abutment tooth generated by the retentive terminal as it passes over the height of contour of the tooth when the partial denture is inserted or withdrawn from the mouth.

Q91. What are the factors which influences the flexibility of the clasp arm?

Ans.The factors which influences the flexibility of the clasp arm are:

  1. Length of the retentive arm
  2. Taper of the arm
  3. Cross-section form of the arm
  4. Type of alloy used.

Q92. What are the types of circumferential clasp?

Ans. The types of circumferential clasp are:

  1. Simple circlet
  2. Multiple circlet
  3. Embrasure clasp
  4. Ring clasp
  5. Fish hook clasp
  6. Onlay clasp

Q93. What are the types of bar clasps?

Ans. The types of bar clasps:

  1. T clasp
  2. Modified claps
  3. Y clasp
  4. I clasp

Q94. What is an indirect retainer?

Ans. The component of a partial removable dental prosthesis that assists the direct retainers in preventing displacement of the distal extension denture base 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.

Q95. What are the functions of an indirect retainer?

Ans. The role of an indirect retainer is to effectively activate the direct retainer to prevent movement of a distal extension base away from the tissue surface.

Q96. In which classification of partially edentulous arch is mandatory to give an indirect retainer?

Ans. In Kennedy’s class I and II, it is mandatory to design aan indirect retainer.

Q97. What are the factors which influences the effectiveness of an indirect retainer?

Ans. The greater the distance between the fulcrum line and the indirect retainer, more effective will be the indirect retainer.

Q98. What are the forms of indirect retainer?

Ans. The forms of indirect retainers are:

  1. Auxiliary occlusal rest
  2. Lingual or cingulum rest
  3. Incisal rest

Q99. What is an occlusal rest?

Ans. A rigid component of the cast partial removable denture that serves primarily to transfer occlusal forces occurring against the prosthesis down the long axis of the abutment tooth.

Q100. What are the functions of occlusal rest?

Ans. Functions of occlusal rest are:

  1. It transmits along the long axis so that the periodontal ligament absorbs the force without damaging the supporting bone
  2. It acts as a vertical stop and prevents injury and over displacement of the soft tissues under the partial denture bases
  3. It maintains the clasp in its position
  4. It prevents food entrapment between the abutment tooth and edentulous ridge
  5. In combination with minor connector,it performs reciprocation action

Q101. What is a dental cast surveyor?

Ans. A paralleling instrument used in construction of a dental prosthesis to locate and delineate the contours and relative positions of abutment teeth and associated structures.

Q102. What are the parts of a surveyor?

Ans. Ney dental surveyor:

  1. Surveying platform
  2. Surveying table or cast holder
  3. Vertical arm
  4. Horizontal arm
  5. Surveying arm
  6. Surveying tools
  7. Analyzing rod
  8. Carbon markers
  9. Undercut gauges
  10. Wax knife

Q103. What are the functions of a surveyor?

Ans. Functions of surveyor:

  1. Surveying diagnostic cast
  2. Tripoding the cast
  3. Transferring tripod marks to another cast
  4. Contouring wax pattern
  5. Contouring crowns and cast restoration
  6. Placing internal attachments and rests
  7. Surveying the master cast

Q104. What is tripod marking?

Ans. Tripod marks or lines drawn on a cast in a single plane perpendicular to the survey rod  to assist with repositioning the cast on a dental surveyor in a previously defined orientation.

Q104. What is an undercut?

Ans. An undercut is:

  1. The portion of the surface of an object that is below the height of contour in relationship to the path of placement.
  2. The contour of a cross-sectional portion of a residual ridge or dental arch that prevents the insertion of a dental prosthesis.

 Q105. What is a tooth supported removable partial denture?

Ans. A dental prosthesis or part of a prosthesis that depends entirely on the natural teeth for support. For example, Kennedy’s  class III partially edentulous situation.

Q106. What is a height of contour?

Ans. A line encircling a tooth and designating its greatest circumference at a selected axial position determined by a dental surveyor or a line encircling a body designating its greatest circumference.

Q107. What are guiding planes?

Ans. Vertically parallel surfaces on abutment teeth or/and dental implant abutments oriented so as to contribute to the direction of the path of placement and removal of a removable dental prosthesis.

Q108. What is a survey line?

Ans. A line produced on a cast by a surveyor marking the greatest prominence of contour in relation to the planned path of placement of a restoration.

Q109. What is a suprabulge?

Ans. The portion of a tooth or crown that converges toward the occlusal surface, i.e.,above the height of contour.

Q110. What is infrabulge?

Ans. That portion of the crown of a tooth apical to the survey line.

Q111. What are the alloys used for fabrication of cast partial denture?
Ans.  The alloy used are:

  1. Cobalt chromium alloys
  2. Titanium alloys
  3. Type IV gold alloys

Q112. What is fixed partial denture?

Ans. Any dental prosthesis that is cemented, screwed or mechanically attached or otherwise securely retained to natural teeth, tooth roots, and/ or dental implant abutments that furnish the primary support for the dental prosthesis.This may include replacement of one to sixteen teeth in each dental arch.

Q113. What are the parts of a fixed partial denture?

Ans. The parts of a fixed partial denture are retainer, pontic and connector.

Q114. Define abutment?

Ans. A tooth, a portion of a tooth or that portion of a dental implant that serves to support and/or retain a prosthesis.

Q115. Define retainer?

Ans. Retainer is a component of fixed partial denture used for stabilization or retention of a prosthesis.

Q116. Define connector?

Ans. In fixed dental prosthesis, the portion of a fixed dental prosthesis that joins the retainer and pontic.

Q117. Define pontic?

Ans. Pontic is the suspended member of the bridge or the artificial teeth of a fixed partial dental prosthesis that replaces missing natural teeth, restoring function and appearance.

Prosthodontics
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