Accuracy of impressions for internal-connection implant prostheses with various divergent angles.
OBJECTIVE
The aim of this study was to determine the accuracies of implant-level impressions for internal-connection dental implants with various angles of divergence.


METHODS
Five groups were created according to the angles of divergence (0, 5, 10, 15, and 20 degrees) between two implant analogs in a master model. A master stone model for each group was fabricated. The divergent angle in each master model was verified with a profilometer. Study models (n = 10) from each master model were constructed through the implant-level impression technique. The divergent angle in each study model was verified with the profilometer. The splinted metal framework with passive fit was cast with base metal and cast-on abutments in each master model. The metal framework was tried in the study models and the fit of each framework was evaluated. One-way analysis of variance and the Tukey Honestly Significant Difference test were used for statistical analysis.


RESULTS
Statistically significant deformations of the impressions were found in the study models with divergently placed implant analogs. A larger divergence angle resulted in a larger gap between the framework and the implant analogs. The gap in the 20-degree divergence group differed significantly from that measured in the master model (P < .01).


CONCLUSIONS
Internal-connection implants were accurate when the divergence angle was less than 15 degrees. Inaccuracy of impressions increased as the divergence angle increased. The inaccuracy was significantly greater for the 20-degree-divergent implants than the other groups.
Department of Prosthodontics, College of Dentistry, Yonsei University, Seoul, South Korea.
Hee-Kon
HK
Jang
Sungtae
S
Kim
June-Sung
JS
Shim
Keun-Woo
KW
Lee
Hong-Seok
HS
Moon
D059605:Dental Implant-Abutment Design / Q000592:standards; D015921:Dental Implants; D003761:Dental Impression Technique / Q000295:instrumentation / Q000592:standards*; D018772:Dental Marginal Adaptation / Q000592:standards; D017267:Dental Prosthesis Design / Q000592:standards*; D019094:Dental Prosthesis, Implant-Supported; D006801:Humans; D008422:Materials Testing; D003765:Models, Dental; D013499:Surface Properties
D015921:Dental Implants