Effect of impression coping and implant angulation on the accuracy of implant impressions: anin vitrostudy

Abstract

PURPOSEThe purpose of this study was to compare the accuracy of the implant master cast according to the type (pick-up, transfer) and the length (long, short) of the impression copings.MATERIALS AND METHODSThe metal master cast was fabricated with three internal connection type implant analogs (Osstem GS III analog), embedded parallel and with 10° of mesial angulation to the center analog. Four types of impression coping were prepared with different combinations of types (transfer, pick-up) and lengths (long, short) of the coping. The impressions were made using vinyl polysiloxane (one step, heavy + light body) with an individual tray, and 10 impressions were made for each group. Eventually, 40 experimental casts were produced. Then, the difference in the distance between the master cast and the experimental cast were measured, and the error rate was determined. The analysis of variance was performed using the SPSS (v 12.0) program (α = .05), and the statistical significance was set at P < .05.RESULTSThe ANOVA showed that the pick-up type impression coping exhibited a significantly lower error rate than the transfer type. However, no significant difference was observed with respect to the length of the impression coping. Additionally, no significant difference was observed between the parallel and mesial angulated groups.CONCLUSIONWithin the limitations of this study, the pick-up type impression coping exhibited a more accurate implant master cast than the transfer type in parallel group. The accuracy of the implant master cast did not differ for different lengths of impression coping of at least 11 mm. Additionally, the accuracy of the implant cast was not different for the parallel and 10° mesial angulated groups.

A Clinical Protocol for Intraoral Digital Impression of Screw-Retained CAD/CAM Framework on Multiple Implants Based on Wavefront Sampling Technology

“…4 In addition, scientific literature has used the term "passive fit" like a total lack of tension between the implant and the framework. Although this basic definition is very under stable, a more concrete or specific aspect of this "passive fit" seems to be difficult issue of agreement between the different authors [5][6][7][8][9][10][11][12] A prosthesis misfit can result in mechanical and biological complications. [6][7] It is believed that biological complications such as loss of osseointegration and marginal bone may arise from a non accurate fitting prosthesis.…”

Current methods and techniques of implant impressions: A literature review

“…Z drugiej strony inni autorzy wykazali, iż mniej zaznaczona nierównoległość w położeniu implantów nie ma wpływu na dokładność wycisków. 30,54,75 Ponadto Conrad i wsp. 76 wykazali, że zarówno metoda wyciskowa jak i kąto-wość położenia implantów nie mają wpływu na dokładność wycisku przy nierównologłości wszczepów rzędu 5 o , 10 o i 15 o .…”

Accuracy of implant transfer using closed tray technique with different viscosities of polyvinyl siloxane

“…Since the passive fit of the superstructure on the abutments is essential for long term success of implant-supported prosthesis [4], making accurate impressions as the first step for achieving this fitness is mandatory [5]. Misfit of the implants could results in many complications including screw loosening, fixture fracture, bone loss and occlusal discrepancy [6][7][8].…”