Purpose. This in vitro study investigates how unilateral and bilateral occlusal loads are transferred to an implant assisted removable\r\npartial denture (IARPD). Materials and Methods. A duplicate model of a Kennedy class I edentulous mandibular arch was made\r\nand then a conventional removable partial denture (RPD) fabricated. Two Straumann implants were placed in the second molar\r\nregion, and the prosthesis was modified to accommodate implant retained ball attachments. Strain gages were incorporated into\r\nthe fitting surface of both the framework and acrylic to measure microstrain (??Strain).TheIARPD was loaded to 120Ns unilaterally\r\nand bilaterally in three different loading positions. Statistical analysis was carried out using SPSS version 18.0 (SPSS, Inc., Chicago,\r\nIL, USA) with an alpha level of 0.05 to compare the maximum ??Strain values of the different loading conditions. Results. During\r\nunilateral and bilateral loading the maximum ??Strain was predominantly observed in a buccal direction. As the load was moved\r\nanteriorly the ??Strain increased in the mesial area. Unilateral loading resulted in a twisting of the structure and generated a strain\r\nmismatch between the metal and acrylic surfaces. Conclusions. Unilateral loading created lateral and vertical displacement of the\r\nIARPD.The curvature of the dental arch resulted in a twisting action which intensified as the unilateral load was moved anteriorly.
Loading....