Evaluation of some factors that may affect the accuracy of implant transfer impression

Abstract EN

Three implants were vertically arranged in a straight line parallel to one another in an acrylic block.

Three impression transfers were manually tightened to the implants by 10 different operators and by a 30 N/Cm torque as a control.

The distance between the transfers was measured under microscope from top and side views.

Three abutments were connected to the implants and an electroformed bridge was constructed to fit them.

Four groups of impressions were made for the implants using abutments as an impression transfers and the ordinary transfers; both were tightened manually and by 30 N/Cm torque.

Impressions were poured into stone using new implant analogues.

Another two groups of impressions were made using abutments that were tightened manually and by torque, but the stone models were made using old implant analogues.

The abutments were connected to each stone model and the electroformed bridge was placed over them.

The bridge seating was evaluated using a travelling microscope.

Conclusions: Within the limitation of this study: 1- On a microscopic scale, the tightening force of the transfer screw does affect its relation to the implant.

2- There is no practical difference between using the transfers or the actual abutments while making impression for implants, whether they were manually tightened or tightened with a controlled torque ratchet.

3- The repeated use of implant analogues for several times may affect the clinical accuracy of the transfer impression.