Effect of Implant Angulation on the Accuracy of Connecting Impression Coping to the Implants With Internal Hex

Different implant angulation, which is unavoidable in clinical situations, can affect the accuracy of impression. The aim of this study was to investigate the effect of fixture position on the accuracy of connecting impression coping to implants with internal hex.

A gypsum model with 4 implants with internal hex connection was prepared. The implants were installed in different mesiodistal angles of 0, 15, 25 and 35 degrees to the longitudinal axis in the gypsum model. To simulate the gums, a gingival mask was injected around the implants to a height of 2 mm. After a training session for senior dental students on how to close the impression coping, forty students were asked to close the impression copings on four implants. The correctness of the impression coping was evaluated by an expert prosthodontist. Data were statistically analyzed using Cochran Q test. Significance level was considered 0.05.

 this article is approved by ethics committee of Arak University of Medical Sciences.

The correct performance of students in connecting the impression coping to the implant at angles of 0, 15, 25 and 35 degrees was equal to 85%, 72%, 52%, 35%, respectively. With the exception of 0 and 15 degree groups, a statistically significant difference was observed between different study groups.

The fixture position has a significant effect on the accuracy of connecting impression coping to the implants with the internal hex and by increasing the implant angulation, the accurate connection the impression coping to the implant decreases.