- In this technique, the secondary impression is made
after the construction of the metal framework and denture base. So, it is referred to as functional reline. - By using this technique, a new surface is added to the
tissue side of the denture base. - This can be done before insertion or later if excessive resorption is present.
- Procedure
- A soft metal spacer (Ash No. 7 metal) is adapted over the ridge on the cast before the metal denture base is being processed.
- After processing, the metal is removed, which leaves an even space between the base and the edentulous ridge.
- Border molding is done and an impression is made using a low-fusing modeling plastic placed over the tissue surface of the denture base.
- The modeling plastic is tempered in a water bath and seated in the patient’s mouth until an accurate impression of the ridge is made.
- The patient should partially open his mouth during the entire procedure.
- After modeling plastic application is complete, about 1 mm of modeling plastic is scraped away uniformly from all over the crest of the ridge.
- The final impression is made with a free-flowing zinc oxide eugenol impression paste. In cases where excessive undercuts are present, elastomeric impression material is used.
Disadvantages
- Occlusion may be altered after the new denture base is processed.
- Previous occlusal contacts cannot be established.
- May be difficult to maintain the correct relationship between the framework and the abutment teeth during the impression procedure.