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Attachments_in_Removable_Prosthodontics

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					    Attachments in Removable
         Prosthodontics
                Dr Anas Alibrahim
            BDS (JUST, Jordan, 2007)
MDSc Prosthodontics (Dundee, United Kingdom, 2010)
Lecture Outline
   Why do we use attachments in removable prosthodontics?
   Retention of removable partial dentures.
   Definition of attachments.
   Classification of attachments.
   Indications for attachments.
   Contraindications for attachments.
   Advantages of attachments.
   Disadvantages of attachments.
   Other attachments and retention devices.
   How to choose appropriate attachments for different cases?
   References.
Attachments
 Retention,
  support and
  stability.
 Can be used with:
 Partial dentures.
 Overdentures.
 Implants.
Retention of Removable Partial Dentures

                  Retention




  Neuromuscular                Inherent physical
                  Mechanical
     control                         forces




     Clasps       Undercuts      attachments
Definition
   An attachment is a
    mechanical device made
    up of two components, one
    located in or on the
    abutments tooth and the
    other housed in the
    denture. When the two
    matched parts are linked
    together they produce very
    positive retention.
Classification
                        Size:
                    Macro or Micro




   Fabrication:                            Location:
     Precision        Attachments        Intracoronal
 or Semiprecision                       or Extracoronal




                       Functional
                     characteristics:
                    Rigid or Movable
Intracoronal Attachments -1

   Two components:
    Matrix and Patrix.
   Sliding joint
    configuration.
   Retain, support and
    stabilise the
    removable partial
    denture.
Intracoronal Attachments -2

   Crowns.
   At least 4 mm vertical
    space.
   At least 3 mm
    buccolingual space.
   Parallelism.
Intracoronal attachment -3

   Location :
    Intracoronal.
   Size :
    Micro attachments.
   Functional
    characteristics:
    Rigid attachments.
   Fabrication:
    Precision or semi
    precision attachments.
Extracoronal attachments -1

   Two components:
    e.g. Dalbo (Patrix)
    and other component
    (Matrix) held in
    denture.
   Sliding joint
    configuration.
   Retain and stabilise
    removable partial
    dentures.
Extracoronal attachments -2
   Reside entirely outside
    the normal clinical
    contour of abutments.
   Need no space within
    the abutment crown.
   May be employed
    where buccolingual
    space is limited.
   often employed to
    retain bilateral distal
    extension prostheses.
Extracoronal attachments -3
   Location:
    Extracoronal.
   Size: Micro
    attachments.
   Functional
    characteristics:
    Rigid or movable
    attachments.
   Fabrication: Precision
    or semi precision
    attachments.
Extracoronal attachments -4

   Rigid : only allow
    movement in one
    direction.
   Movable: movement
    allowed should be
    regarded as a safety
    valve and not as a
    means of anchoring
    an unstable prosthesis
    to natural teeth.
Macro attachments
          E.g. Telescopic crowns
Indications
   When neither fixed bridge
    nor clasp retained denture
    would be satisfactory.
   Small bounded saddles
    with considerable bone
    loss.
   Retain bilateral distal
    extension prosthesis.
   Join a series of crowns
    which don’t have common
    path of insertion.
   Overdentures.
   Implants.
Contraindications
   Short clinical crowns of abutment teeth
    (Intracoronal attachments).
   Limited buccolingual space of abutment teeth
    (Intracoronal attachments).
   Large size of pulp
    (Intracoronal attachments).
   Poor periodontal health of abutment teeth
    (Rigid attachments).
   Lack of experience and clinical skills
    (Extra and Intracoronal attachments).
   Bad oral hygiene
    (Extra and Intracoronal attachments).
Advantages
   Better aesthetic results and more effective
    retention than clasps.
   More apical functional load transfer to abutments
    than rests (Intracoronal attachments).
   Diminish rotational movements of abutments
    (Intracoronal attachments).
   Improved cross arch load transfer and
    stabilisation of prosthesis.
   Limit the potentially damaging force imparted to
    abutments (Extracoronal attachments and
    Intracoronal attachments).
Disadvantages
   Abutment teeth
    usually have to be
    crowned.
   Occupy a lot of space.
   Encourage plaque
    accumulation.
   Require ongoing
    maintenance.
   Clinical and technical
    skills are demanding.
   Relatively expensive.
Other attachments and retention devices -1

   Stud attachment
•   Used with
    overdentures.
Other attachments and retention devices -2

   Magnets
   No demands on the
    periodontal tissues of
    abutment teeth.
Other attachments and retention devices -3

   Two parts denture
•   Needs good manual
    dexterity.
How to choose appropriate attachments
for different cases? -1

   Personal design
    philosophy
•   Rigid or movable?
•   How much resiliency?
How to choose appropriate attachments
for different cases? -2

   Condition of the
    abutment teeth
•   Intra or extracoronal
    attachments?
How to choose appropriate attachments
for different cases? -3


   Condition of the non-
    abutment supportive
    structures
    (periodontal tissues
    and alveolar ridge)
•   Rigid or movable ?
How to choose appropriate attachments
for different cases? -4


   Manual dexterity
•   Intra or extracoronal
    attachments ?
References

Stewart’s Clinical Removable Partial
 Prosthodontics, Third Edition. Chapter 20,
 Attachments for removable partial
 dentures, pages 507-515.
 Preiskel, H. W. (1974). "Precision
 attachments for the partially dentate
 mouth." Annals of the Royal College of
 Surgeons of England 55(6): 294-298.

				
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