Copy Dentures

Question 1

What does successful dentures depend on?

Answer 1

• Adaptation to foreign body in mouth
• Neuromusclar adaptation
• Becomes more difficult as patient ages

Question 2

What is the goal of copy dentures?

Answer 2

• Keep similar contours and extensions as old dentures a
• Similar tooth dimension
• Minimal change in OVD
• Makes adaptation much easier

Question 3

What are the indications and contraindications of copy dentures?

Answer 3

Indications

• Pt happy with existing dentures
• Dentures loose due to bone resorption
• Overclosed due to tooth wear

Contraindications

• Severe undercuts
• Requiring adjustment of current denture to proceed–>if your new dentures don’t work out, you risk ruining their old ones

Question 4

What should you inform your patient when planning copy dentures?

Answer 4

-They need to leave dentures with you for a day or two

Question 5

What should you write to the lab when doing copy dentures?

Answer 5

• Please pour master impressions + mount on articulator
• Please set up teeth on wax (or CCA) bases (this is the wax denture initial try-in)
• Any adjustments (e.g. setting upper teeth 1mm longer, with similar shape, set lower teeth in normal overbite/jet)
• Clean up dentures for return at try in

If patient satisfied, carve palatal seal, and ask lab to process and finish

Question 6

What tends to happen as denture wears?

Answer 6

-Patient tends to protrude creating a pseudo class III

Question 7

Should teeth be placed all the way to the back of the dentures? Why or why not?

Answer 7

No

• Tends to confines tongue
• Increases risk of tongue/cheek biting
• Usually leave one premolar off if insufficient space

Question 8

What are the steps for doing copy dentures?

Answer 8

1. Assess stability and need for reline + occlusal record + need to re-open OVD
2. If needed then:
   - Take re-line impression with current dentures
   - Take occlusal record with current dentures
   - Can open OVD by placing wax (horse-shoe wax is approximately 2mm thick and is great for opening OVD by this amount for worn teeth)
3. Send appropriate materials to the lab

Lab:

1. Study models will be poured using the denture (if re-line impression was taken using denture as tray this will be recorded in the cast/model thus providing the new arch shape)
2. Study models are mounted on articulator and positioned by either: current denture occlusion, new occlusal record, wax occlusal record with opened OVD
3. Acrylic replica of denture base is generated by:
   * Mixing a large amount of putty and pushing the denture tooth first into it, thus taking impression of occlusal surface
   * Wait until putty set, then carving 3 locating grooves into it
   * Mixing more putty and putting this over the top of the denture to take impression of fitting surface while leaving it in place in the first putty mould
   * As the first putty mould has already set, the two putty halves won’t join together, and locating grooves help fit putty halves together
   * When putty halves are put together, mould forms the shape of the original denture
4. Denture is removed and wax or CCA is flowed into the mould and container closed, thus creating the shape of the original denture

Clinic:
1. Try in of wax denture

Lab:
If patient unsatisfied, teeth can be carved off and replaced with new teeth, and a new putty copy mould is created

If patient is satisfied, tooth impressions are filled with tooth coloured acrylic material and allowed to set and excess trimmed. This is then replaced into the mould