Objectives: Maxillofacial prostheses using craniofacial implants have been fabricated with both splinted and non-splinted designs. The use of individual implant attachments may provide greater ease in fabrication of prostheses, improved hygiene access for patients, and reduced costs. The purpose of this study was to examine the load transfer and retention characteristics of implant attachments for craniofacial implants. Methods: The attachments tested were: Locator (Zest Anchors); ERA (Sterngold Attachments); Dome Magnet (MAGFIT-IP-BD, Aichi Steel Corp.); Flat Magnet (MAGFIT-IP-BD, Aichi). The attachments were evaluated in combination with three individual craniofacial implants (Nobel Biocare, 3.7mm dia, 4.0mm long; BUD, 3.1mm, 3.7mm long; ITI, 3.2mm, 3.9mm long). Each implant design was positioned with its flange submerged under the surface of a photoelastic bone simulant representing complete integration. The dislodgment potential of the attachment-implant combinations was determined using a calibrated load cell. Axial and inclined forces, simulating prosthesis seating and removal, were applied and the stresses developed in the bone simulant were recorded photographically in a circular polariscope. Results: Locator was most retentive in axial (2.57±0.09lb) and inclined (2.85±0.06lb) conditions. ERA exhibited same retention for both conditions (1.31±0.04lb), as did the domed magnets (0.81±0.05lb). The flat magnets were less retentive with inclined pull (0.83±0.04lb) than axially (1.27±0.06lb). Under insertion forces, the highest stresses occurred with the BUD, lowest with ITI and intermediate with Nobel Biocare for all attachments. For all attachments and implants, inclined removals produced lower stresses than axial removal. Magnets generally produced similar stresses, except being higher with the dome under inclined insertion. Conclusion: Locator generally demonstrated highest retentive capacity. Regardless of attachment, BUD implant generated highest stresses in supporting structure under all loading conditions. Both magnets showed lower retention and stress production under insertion and removal loads. Selection of implant-attachment combination depends upon the requirements and dexterity of the patient.

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