Retention and Mechanical Behavior of Attachment Systems for Implant-Retained Auricular Prostheses

OBJECTIVE: Auricular prostheses are artificial substitutes for facial defects. The retention of these has often been a problem. This study aimed to evaluate the mechanical behavior of 3 retained auricular prosthetic connections when submitted to a mechanical cycling test. MATERIALS AND METHODS: Twelve samples with installed implants were obtained and divided into 3 groups according to their retention system with 4 samples in each group. I: bar-clip system; II: magnet system; and III: ball/o-ring system. Each of samples was submitted to the pull-out test during 3240 cycles (f = 0.5 Hz) to determine its tensile strength. The mechanical cycling test was performed using the servo-hydraulic machine MTS 810-Flex Test 40 (Eden Prairie, MN) that had a 2.5 mm shift at a 10 mm/s velocity. The retaining strength for each of the samples was obtained at 7 intervals. RESULTS: The tensile strength for the group retained by the bar-clip system (29.60 N) was higher with statistically significant difference (P < 0.05) when compared with the group retained by the ball/o-ring system (9.41 N) and magnets system (8.61 N) for all periods assessed. The ball/o-ring system showed loss of retention during the fatigue test (Kruskal-Wallis, chi-squared = 17.28; P < 0.01). CONCLUSIONS: The evaluated systems showed a tensile strength compatible with the clinical use and no fractures of the components were observed.