Three implant impression techniques, using 3 different splinting materials,
were assessed for accuracy in a laboratory model that simulated clinical p
ractice. For group A, an autopolymerizing acrylic resin was used to splint
transfer copings. In group B, a dual-cure acrylic resin was used, and for g
roup C, plaster, which was also the impression material, was used. A metal
implant master cast with an implant master framework was made to accurately
fit to the cast. This cast was the standard for all impressions. For each
group, 15 impressions were made. Polyether impression material was used for
groups A and B. The accuracy of the stone casts with the implant analogues
was measured against the master framework, using strain gauges. A multiple
analysis of variance with repeated measures was performed to test for sign
ificant differences among the 3 groups. Additional analyses of variance wer
e carried out to locate the source of difference. The statistical analyses
revealed that a significant difference existed between groups A and B and b
etween groups B and C but not between groups A and C. Impression techniques
using autopolymerizing acrylic resin or impression plaster as a splinting
material were significantly more accurate than dual-cure acrylic resin. Pla
ster is the material of choice in completely edentulous patients, since it
is much easier to manipulate, less time consuming, and less expensive.