The purpose of this in vitro study was to determine the biomechanical values of the SonicWeld Rx pin system in comparison with titanium screws for use in onlay cortical bone grafting. In this study, 2.1-mm SonicWeld Rx pins and 1.5-mm titanium screws, measuring 7 mm in length, were used. Sawbone blocks were positioned to simulate an onlay bone graft, and the pins and screws were used to replicate bicortical fixation. Four groups were designated for vertical load application, and failure of the fixation was determined when stability was compromised. Study groups consisted of fixation material types and number of fixation appliances. A Bose Electroforce 3300 system was used to deliver the force and to obtain data. Comparison of SonicWeld Rx 1-pin fixation with titanium 1-screw fixation showed similar peak resistance loads. Average peak loading resistance for SonicWeld Rx 1-pin fixation was 65.54 N and that for titanium 1-screw fixation was 59.37 N, with no significant difference (P = .9698). Average peak strength of SonicWeld Rx 2-pin and titanium 2-screw fixations was 110.24 and 97.3 N, respectively, with no significant difference (P = .1041). Based on the measured biomechanical values, SonicWeld Rx fixation can withstand similar peak load forces compared with that of titanium screw fixation. The SonicWeld Rx fixation can be an alternative method of fixation for onlay bone grafting in dentoalveolar ridge augmentation. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.