Trial Method Using Adhesive For Accurate Implant Working Casts

Trial Method Using Adhesive For Accurate Implant Working Casts
10 March 2005
Y. ISHIURA, T. MIYAZAKI, and T. KAWAWA, Showa University, Tokyo, Japan
IADR
Objectives: The aim of this study was determine a method to make a more accurate implant working cast. Until now, our results indicate that the implant rotates when using an impression coping of the IAT Fit II implant system (Ishifuku, Tokyo). Methods: A three-dimensional microscope was used to measure reference points on the master model and working casts. Impressions were taken from a master model with two implants (I1 and I2) using adhesive painted (ADH) or non-painted (control) impression copings. The dental stone was poured into an impression; the impression was removed (1hour later), stored (24hours), and measured. Results: Except for the implant site, movements of reference points were similar to our previous studies; every point moved outwardly. The mesial implant (I1) rotated 0.22degrees (control) and 0.54degrees (ADH); the distal implant (I2), 0.32degrees (control) and 0.42degrees (ADH). The amount of dimensional change between I1 and I2 was 6.1micrometers (control) and -1.6micrometers (ADH). Discussion: The indirect method is commonly used to make superstructures of implants. Impression taking, working cast making, waxing-up and casting are unavoidable. An implant superstructure needs to be more accurate than a natural prosthesis, so an accurate working cast is needed. Rotation of implants and inter-implant distances are most important when making a frictional fit superstructure. In this study, the degree of implant rotation of the control and the ADH implants was similar. Although it is impossible to make a single-implant superstructure using a free-type gold coping for a multi-implant superstructure, rotation of the implant can be ignored. With the ADH, the absolute amount of dimensional change between the two implants was smaller than that of the control, so the ADH can make a more accurate implant working cast and implant superstructure. Conclusion: The ADH produces a more accurate implant working cast and implant superstructure than the control.