Retention and Wear Performance of Locator Attachments Under Cyclic Loading: An In Vitro Study

The objectives of the current study were to evaluate and compare the retention loss and wear rates of locater attachments made of three different materials under cyclic load.

Three locater attachments, including those made of titanium nitride-coated (conventional Locator), titanium carbon nitride-coated (Locator R-Tx), and zirconia (TAV Locker), were used to produce 42 specimens. Half of the samples in each group were placed straight, while the other half were positioned at the maximum recommended angulation in custom aluminum molds. Each sample was treated to 5,000 insertion-separation cycles. Retention forces were assessed after 10, 500, 1,000, 4,000, and 5,000 insertion-separation cycles. Furthermore, the wear of the attachments was assessed using the mass loss technique and scanning electron microscopy.

Although the mean retention values of the angle-placed attachments did not differ significantly across all cycles (p > 0.05), there was a statistically significant difference in the mean retention values of the straight-placed attachments across all cycles. titanium carbon nitride demonstrated higher retention values in each retention test cycle compared to titanium nitride-coated and zirconia locator attachments (p≤0.001). The greatest weight loss among the locator attachments was observed in the titanium carbon nitride-coated angle-placed group (-0,066), while among the nylon inserts, the titanium nitride-coated angle-placed group exhibited the most significant weight loss. (-2,727).

The retention force of the titanium carbon nitride-coated group was statistically higher both in straight and angle-placed specimens at the beginning and end of the study compared to the other attachment groups.