Impression Taking Techniques for Fit-to-Partial Cases

There are 2 popular ways to take fit-to-partial impressions:

1. By taking a pickup impression with cast partial denture in the impression.
2. By taking an impression of patient’s mouth without the cast partial denture.

Pros and Cons:

1. By taking a pickup impression with cast partial denture in the impression.
   • Pros:
     • Cast partial denture will fit on the model better after model is poured up
     • Accuracy of the crown fitting to the partial denture will be better, so there will be less adjustments chair side
   • Cons:
     • This technique is more difficult to capture accurate impression
     • It is harder to remove pick up impression tray and cast partial denture at the same time chair side
     • After model is poured up, to remove the cast partial denture from the impression, the impression will need to be cut open. So the impression cannot be reused to pour up another model

*Technique:
1. Make sure to select the right size impression tray
2. Remove cast partial denture from patient’s mouth
3. Inject light body around patient’s prepped tooth while the dental assistant fills the impression tray with heavy body
4. Place cast partial denture in patient’s mouth
5. Immediately, place impression tray with heavy body in patient’s mouth
6. After setting, remove tray with cast partial denture
7. Send pick up impression to the lab for fit-to-partial fabrication

2. By taking an impression of patient’s mouth without the cast partial denture.
   • Pros:
     • Easier procedure to take impression
     • Impression tray can be reused to pour model again
   • Cons:
     • Due to impression was taken without cast partial denture, when seating the cast partial denture on the model, it may cause interference causing the cast partial denture to not sit all the way down in the model
     • May require more adjustments of crowns and clasps chair side compared to pickup impression technique

*Technique:
1. Take the impression the same way you would for a regular prepped tooth impression
2. Send cast partial denture and the impression to the lab for fabrication