Swing-lock dentures 4m***

  1. Swing-lock RPDs are used, when a number of remaining teeth is too few to support a conventional design. 
  2. This denture has a labial bar extending labially all along the arch like a major connector. 
  3. The labial bar is connected to the remaining parts of the denture by a hinge on one side and a lock on the other. 
  4. The labial bar can be unlocked during insertion and locked after insertion. 
  5. Indications 
    1. Missing key abutments 
    2. When the number of remaining natural teeth is less 
    3. When the remaining teeth are too mobile to serve as abutments 
    4. When the soft tissue and the tooth are in unfavorable contours 
    5. Provide retention and stability for maxillofacial prostheses, such as obturators 
    6. For retention of the prosthesis in case of loss of large segments of teeth and alveolar ridge, due to trauma or infection. 
  6. CONTRAINDICATIONS
    1. When the vestibule is shallow 
    2. High labial frenal attachment 
    3. Patient with poor oral hygiene 
  7. Advantages 
    1. The construction is relatively simple and inexpensive. 
  8. Disadvantages 
    1. It is unaesthetic in patients with short lips. 
    2. Tipping is seen in the remaining anterior teeth in the distal extension case. 

Fabrication 

  1. Selection of metal for swing-lock framework
    1. The metal of choice is chrome alloy. 
    2. Gold alloys wear off due to constant movement
  2. Surveying and designing 
    1. The cast is mounted on the surveyor. 
    2. The path of insertion is from a lingual direction with the labial arm open. 
  3. Lingual plate
    1. The lingual plate should be designed to end above the survey line. 
    2. It prevents the tissueward displacement.
  4. Occlusal rest 
    1. helps to prevent tissueward displacement of the denture. 
  5. Major connector 
    1. The mandibular major connector extends above the survey line with scallops extending up to contact points. 
    2. The maxillary major connector is the complete palatal or closed horseshoe with borders extending up to or above the survey line. 
  6. Labial arm design 
    1. The vertical projection of the labial bar should be designed to touch the teeth below the height of contour. 
  7. Conventional design
    1. This consists of a labial bar with metallic vertical I-bar or T-bars attached to it.
    2. Using acrylic resin retention loop 
    3. This is indicated for patients with short lips and where aesthetics is of concern. 
  8. Selection of impression material = Heavy-bodied alginate is best preferred. 
  9. Tray selection = A custom tray should be used for recording maximum labial and buccal vestibular depths.
  10. For the secondary impression, 5–6 mm space should be given between the teeth and the tray when placed in the mouth. 
  11. Making the impression. 
    1. It is similar to conventional dentures. 
    2. Dual impressions may be required for distal extension.
  12. Framework fabrication.
  13. Fitting the framework.
  14. Arranging artificial teeth to occlusion 
  15. Insertion = Lingual path of insertion is done. 
  16. Post insertional care = Oral hygiene should be maintained by the patient. Distal extension RPD has to be frequently relined. 

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