Rest and Rest Seats in Partial Dentures
46 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of a rest in a partial denture?

  • To enhance esthetics
  • To provide vertical support (correct)
  • To distribute occlusal forces
  • To improve speech

    • The width of the occlusal rest seat form should be approximately 4 mm.

    False

    How much should the marginal ridge be lowered in preparation for an occlusal rest seat?

    1 to 1.5 mm

    The rest seat should have a __________ shape for optimal support.

    <p>rounded triangular</p> Signup and view all the answers

    Match the following attributes with their descriptions regarding occlusal rest seat form:

    <p>Concave floor = Prevents horizontal stresses Apex directed towards center = Directs occlusal forces along the tooth axis Smooth outline = Eliminates sharp line angles Rounded marginal ridge = Provides strength and prevents fracture</p> Signup and view all the answers

    What is one critical feature of the floor of an occlusal rest seat?

    <p>Concave or spoon-shaped</p> Signup and view all the answers

    The angle formed by the rest and minor connector should be greater than 90 degrees.

    <p>False</p> Signup and view all the answers

    What is the ideal angle formed by the rest and minor connector?

    <p>Less than 90 degrees</p> Signup and view all the answers

    The base of the triangular occlusal rest seat should be approximately __________ the bucco-lingual width of the tooth.

    <p>one third</p> Signup and view all the answers

    What is the purpose of a boxed-shaped occlusal rest?

    <p>To provide guide-surfaces for tooth-supported dentures</p> Signup and view all the answers

    Extended occlusal rests should be less than one-half the mesiodistal width of the tooth.

    <p>False</p> Signup and view all the answers

    What is one advantage of using a casting for a severely tilted posterior abutment tooth?

    <p>Direct the forces along the long axis of the tooth.</p> Signup and view all the answers

    The _____ rest helps in preventing lateral movement of the denture.

    <p>occlusal</p> Signup and view all the answers

    Match the following types of rests with their descriptions:

    <p>Occlusal Rest = Rest positioned on the occlusal surface of teeth Lingual Rest = Rest placed on the lingual side of the teeth Incisal Rest = Rest located on the incisal edge of anterior teeth Embrasure Hooks = Hooks used to engage the embrasure spaces</p> Signup and view all the answers

    Which of the following is NOT a type of rest mentioned?

    <p>Distal Rest</p> Signup and view all the answers

    What is the primary purpose of the occlusal rest in dental prostheses?

    <p>To prevent slippage of the prosthesis</p> Signup and view all the answers

    A cingulum rest is also referred to as an inverted V rest.

    <p>True</p> Signup and view all the answers

    An amalgam restoration is suitable to support an occlusal rest.

    <p>False</p> Signup and view all the answers

    What is the recommended thickness for an extended occlusal rest?

    <p>At least 1 mm thickness.</p> Signup and view all the answers

    What should be prepared in enamel if there is a low caries index and good oral hygiene?

    <p>Rest seat</p> Signup and view all the answers

    To prevent the extrusion of the tooth, a _____ is utilized in the partial denture framework.

    <p>rest</p> Signup and view all the answers

    The occlusal rest must fit the tooth to minimize ___ collection.

    <p>food</p> Signup and view all the answers

    Match the following functions of the occlusal rest to their descriptions:

    <p>Support = Prevents settling of the prosthesis Transmits Vertical Stress = Distributes stress along the long axis of the tooth Maintain Clasp Position = Keeps clasp in proper alignment Indirect Retention = Prevents extrusion of abutment teeth</p> Signup and view all the answers

    Which of the following is NOT a requirement of the occlusal rest?

    <p>Must raise the vertical dimension of occlusion</p> Signup and view all the answers

    Guiding planes must be established before making the master cast.

    <p>True</p> Signup and view all the answers

    What is one function of an occlusal rest regarding lateral displacement?

    <p>Resistance to lateral displacement</p> Signup and view all the answers

    The interproximal occlusal rest seat is modified to provide space for the ___ and ___ arms.

    <p>retentive, bracing</p> Signup and view all the answers

    Which type of rest is primarily indicated when there is no posterior tooth available?

    <p>Cingulum Rest</p> Signup and view all the answers

    A cingulum rest can be prepared on an incisor when no canine is available.

    <p>True</p> Signup and view all the answers

    What is the incisal apical depth for a cingulum rest?

    <p>1.5 mm</p> Signup and view all the answers

    The depth of a ball rest is ______ mm.

    <p>1.5</p> Signup and view all the answers

    Match the type of rest to its description:

    <p>Cingulum Rest = Prepared with a prominent cingulum Ball Rest = Spoon-shaped with no sharp line angles Canine Ledge = Step-like preparation usually for canines Incisal Rest = More applicable on mandibular teeth</p> Signup and view all the answers

    What is an important consideration when preparing a cingulum rest seat?

    <p>Maintaining a prominent cingulum</p> Signup and view all the answers

    The width of an incisal rest should be 2.5 mm.

    <p>True</p> Signup and view all the answers

    What type of rest seat is shaped like a spoon and has a more difficult preparation due to incline?

    <p>Round Lingual Rest Seat</p> Signup and view all the answers

    The MD length of a cingulum rest is ______ mm.

    <p>2.5</p> Signup and view all the answers

    Which type of rest is considered preferable due to its aesthetic advantages?

    <p>Lingual Rest</p> Signup and view all the answers

    The incisal rest exerts less mechanical leverage than the lingual rest.

    <p>False</p> Signup and view all the answers

    What is one advantage of a lingual rest in dental applications?

    <p>It is more aesthetic.</p> Signup and view all the answers

    The _____ hooks act as indirect retainers in dental applications.

    <p>Embrasure</p> Signup and view all the answers

    Match the dental components with their main characteristics:

    <p>Occlusal Rest = Supported from the occlusal surface Lingual Rests = Preferred for esthetics Incisal Rest = Exerts greater mechanical leverage Embrasure Hooks = Support splinting of teeth</p> Signup and view all the answers

    Which of the following is NOT a disadvantage of embrasure hooks?

    <p>Support for natural teeth</p> Signup and view all the answers

    A lingual rest will exert less leverage and reduce tendency to tipping compared to the incisal rest.

    <p>True</p> Signup and view all the answers

    What is the primary function of embrasure hooks?

    <p>To support and splint natural teeth.</p> Signup and view all the answers

    Applying force near the top of the post will remove it more readily than applying the same force near the _____.

    <p>ground level</p> Signup and view all the answers

    What is the primary reason lingual rests are preferable to incisal rests?

    <p>Closer to center of rotation</p> Signup and view all the answers

    Study Notes

    Rest and Rest Seats

    • Rigid extensions of partial dentures that provide vertical support by resting in prepared seats on occlusal, lingual, or incisal surfaces.
    • Quality of the prosthesis is essential to resist movement towards the tissues.

    Occlusal Rest

    • A rigid extension of a removable partial denture (RPD) that contacts the occlusal surface of posterior teeth.
    • Rest seats should be rounded and triangular, with specifications for dimensions: about 2.5 mm wide, base at the marginal ridge.
    • The triangular base should be one-third the bucco-lingual width of the tooth, with a smooth contour and no sharp line angles.
    • The marginal ridge is lowered approximately 1-1.5 mm to ensure sufficient bulk and prevent fracture.

    Occlusal Rest Seat Form

    • Floor of the rest seat should be concave or "saucer-shaped" to prevent horizontal stresses and torque.
    • Angle between rest and minor connector should be less than 90 degrees; deepest portion is central.
    • Proper design directs occlusal forces along the tooth's long axis, preventing slippage and orthodontic movement.

    Preparation Conditions

    • Use enamel for rest seat preparation only if caries index is low and oral hygiene is maintained.
    • Amalgam restorations are unsuitable; replace with a cast restoration if present.

    Double Embrasure Rest Seat Form

    • Adjacent interproximal occlusal rest seats require modification for better retention and positioning of RPD components.
    • Ensure all line angles in rest seat preparations are smooth and rounded.

    Requirements of the Occlusal Rest

    • Must fit the tooth to minimize food accumulation and maintain location.
    • Should withstand loads without deforming.
    • Should not raise the vertical dimension of occlusion.

    Functions of the Occlusal Rest

    • Supports the RPD and prevents settling.
    • Transmits vertical stress along the tooth's long axis.
    • Maintains proper clasp positioning.
    • Distributes occlusal load and resists lateral displacement.
    • Acts as indirect retention and prevents extrusion of abutment teeth.

    Special Considerations

    • Box-shaped occlusal rests are limited to healthy periodontal conditions.
    • Tipped molars may require additional or extended occlusal rests to maintain stability and restore occlusal planes.

    Lingual Rests

    • Commonly referred to as cingulum rests, these can substitute when posterior teeth are absent, ideally placed on canines or incisors.
    • Preparation includes rounded, non-undercut forms, with a minimum depth of 1 mm.

    Ball Rest and Canine Ledge

    • Ball rests are smooth and typically 1.5 mm deep and 2.5 mm wide.
    • Canine ledge rests require step-shaped preparations with no sharp angles.

    Incisal Rest

    • Predominantly used as auxiliary rests for mandibular teeth; 2.5 mm wide and 1.5 mm deep.
    • Lingual rest is more esthetic and less bothersome for the tongue compared to incisal rests.

    Embrasure Hooks

    • Provide support and splinting of natural teeth, acting as indirect retainers.
    • Noted for poor esthetics and potential wedging action on adjacent teeth.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Dental Rest and Rest Seats PDF

    Description

    This quiz covers essential concepts about rest and rest seats in removable partial dentures, focusing on their design and importance in prosthetics. Understanding the specifications for occlusal rests and proper rest seat forms is crucial for successful dental practices.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser