Impact of design and length on the accuracy of closed tray transfer copings

BACKGROUND: The aim of this study was to evaluate the accuracy of two closed-tray transfer copings for implant impressions (a new design vs. an old design) in two different lengths (short and long). MATERIAL AND METHODS: Four groups of transfer copings (NS - new short, NL - new long, OS - old short and OL - old long) were tested. An epoxy resin model was prepared of missing teeth 1.4, 1.5 and 1.6. Two Alpha-Bio analogues were placed in position of teeth 1.4 and 1.6, at a 10o angulation. Two calibrated operators took 10 closed-tray impressions for each group with polyether in a Rim-Lock impression tray. RESULTS: After measuring and comparing impressions, a significant difference was found between the two new transfer copings and the old short transfer coping. CONCLUSIONS: The new transfer coping design significantly improved impression accuracy. An adequate transfer coping design for the closed-tray impression technique can help to achieve clinically acceptable impressions for two-unit implant supported bridges. Key words:Closed tray, impression coping, transfer coping, implant impression.