Crown Under Partial

We refer to this as the "under partial / no partial" case, or stated on your prescription directions, as 'UPNP'. By following the steps outlined below, excellent results can be achieve `and keep your patients smiling.

Step One : Routine prep and impression procedure

  1. A. Check for adequate clearance between prep, rests, and clasps.
  2. Take impression without the partial in place.(Refer to photo)
  3. This impression will become our master model, so an accurate, clear margin is necessary.
  4. Take opposing impression and bite registration.

Step Two : Making the 'Mini' impression for relation of partial to crown. (*Impression tray and clear margins NOT necessary for this small clasp impression.) (Refer to photo)

  1. Inject Impregum or Polyvinylsiloxane (must be heavy body) on and around prep at the location where the partial makes contact.
  2. Inject Impregum or Polyvinylsiloxane on the inside of the rest and clasp area where it contacts the prepped tooth. (Use care to avoid trapping air)
  3. Seat partial in mouth, checking to ensure accurate alignment of partial to all teeth. This is a 'must'!
  4. Hold in place until impression material has set.
  5. Remove partial from mouth and carefully ease impression material from the partial.
  6. Send this 'mini' impression with the master impression, opposing model, and bite registration. Indicate UPNP on the prescription.

* If multiple abutment teeth are to be prepped under partial, follow same procedures as above, injecting impression material around each of the preps, clasps, and rests and seating the partial at one time.

Step Three : Upon receiving your UPNP case, we recreate the clasp and rest area of the patient's partial through means of wire and Duralay to conform to the 'mini' impression. Refer to Photo

Step Four : The under partial crown is waxed to the Duralay clasp, then cast and processed following standard procedures. Contouring of the crown utilizes the pseudo clasp in establishing clasp fit, undercut, and rest areas. Refer to Photo