The

In this study, we investigated the retention of two attachment types, Straumann ball (SB) and Straumann LocatorThe attachments placed on angulation of 0°-, 10°-, and 20° implants were subjected to 1440 vertical insertion-separation cycles. The retention values of the attachments after 0, 720, and 1440 cycles were measured using the Instron machine. In addition, scanning electron microscopy images of the attachments and abutments were obtained before and after the insertion-separation process.There was a significant difference between the SB and SL attachments that were placed on 0° after 1440 cycles (P0.05) and between 20° SB and 20° SL attachments after 720 and 1440 cycles (P0.05) in terms of retention. No significant difference was observed between 20° SB and 20° SL attachments at 0 cycles (P0.05).In implants with a 20° angle, retention of stud attachments decreased more than ball attachments after use. Thus, the total angle between the implants should not be20° if long-term retention is desired when using stud attachments. For implants with angles20°, 6-month patient controls are required to control retention of attachments by considering factors in the mouth with the two tested attachment systems.