Copy Dentures

Question 1

Name 4 errors that can occur when making complete dentures

Answer 1

1. Errors on production of mould - e.g air bubble after using alginate, would make final denture impossible to be seated. Shiny vs matte silicone putty - matte means it hasn’t touched the fitting surface
2. Vertical dimension errors introduced:
   - Must check vertical dimension of copy dentures vs patients old dentures. Must always refer back and compare to OG dentures
   - a) thickness of wash impression: YOU CAN PREVENT THIS BY cutting a hole in the wax up denture - relief hole in centre of palate, prevents build up of impression material and allows you to seat copy denture down fully

-b) Thickness of registration material
3-4mm is quite a lot to increase VD by - if you have lost that much VD over time if dentures are very worn down, may need to consider conventional remake of denture

3. c) Changes to base and arch shape
   - ILL FITTING BASE = rocking
   -Poor retention - upper (if you have really bad retention, just do an upper denture normal Increase in vertical dimension - inadequate seating (using willis gauge)
   -Discomfort - either too big or there’s some part of the denture fitting surface putting pressure there and making it uncomfortable
   SHOULDN’T USE FOR FLABBY RIDGES
   - Haven’t carried out sufficient border moulding of buccal periphery before imp = change in shape and extension. Must stabilise denture with fingers on both occlusal sides when taking imp, manipulate pts soft tissues
   - CHANGES TO ARCH SHAPE:
   Base shift during imp taking
   - Technical errors due to poor definition or technique
   - The teeth have been placed more labially anteriorly and more lingually posteriorly- lab error
4. d) Changes to appearance
   - Poor appearance
   - Poor tooth selection
   - Must give technician mould shape
   - WHY MIGHT TECHNICIAN SELECTING TOOTH MOULD FROM WAX REPLICAS A BAD IDEA? Wax shrinks when solidifying - either select tooth mould again and provide that with the technician, or pour plaster into denture mould for anterior portion as it’s more dimensionally stable