Relationship between impression method of mucosa-borne area and denture pressure supportability

In order to develop a more rational impression method, we examined the relationship between impression method and denture pressure supportability through the denture. Measured with denture bases prepared from impressions taken under various pressures, pressure supportability generally increased with increasing impression pressure. However, the pressure supportability of a denture base prepared from a slight-pressure impression taken under minimum pressure was greater in some cases than for a middle-pressure impression performed under a more pressure. The impression pressure required to produce maximum pressure supportability were calculated based on the area projected from the occlusal plane and ranged from 1.24 to 2.44 kg/cm2 (0.12 to 0.24 MPa). Values calculated based on the surface area of the denture-supporting mucosa ranged from 0.83 to 2.48 kg/cm2 (0.08 to 0.24 MPa). Pressure supportability of the great-pressure impression was 1.3 to 2.6 times higher than that of the slight-pressure impression and 1.2 to 1.8 times greater than that of the alginate impression. Viewed from a clinical standpoint, the great-pressure impression is more effective than the alginate and no-pressure (slight-pressure) impressions in increasing denture pressure supportability.