Peri-implant Strain Evaluation of Ti Si Snap Versus Locator Attachments in Two-Implant Retained Mandibular Overdentures: An In Vitro Study

Aim: This in vitro study was conducted to evaluate peri-implant strain induced by ‎two different types of attachments; (Ti Si snap and Locator) in implant-retained ‎mandibular overdentures. ‎ Materials and methods: Twelve completely edentulous acrylic resin models were 3D printed. ‎Two implant analogues were inserted in each model in the intra-foraminal region. ‎Acrylic resin mandibular overdentures were fabricated over two types of implants ‎attachments: Group I involved Ti Si snap attachment while Group II involved Locator ‎attachment, where n=6 for each group. Retention sil was applied as the female ‎component in the fitting surface of overdentures of both groups. Strain gauges were ‎bonded to the model at the mesial and distal surfaces of each implant analogue. The ‎peri-implant strain was recorded during unilateral and bilateral loading using a ‎universal testing machine. Data were collected, tabulated, and statistically analyzed ‎using independent sample-t test at a 95% level of confidence. ‎ Results: Group I (Ti Si group) revealed a higher induced strain compared to Group II ‎‎(Locator group) during bilateral loading as well as on the loaded side during unilateral ‎loading. However, Group I (Ti Si group) showed significantly reduced mean strain ‎values at the unloaded side in comparison to Group II (Locator group) . ‎ Conclusion: Based on the limitations of this study, it could be concluded that Locator ‎attachment exhibited a better stress distribution pattern compared to Ti Si attachment ‎retaining mandibular overdentures during bilateral loading and on the loaded side ‎during unilateral loading. ‎