OBJECTIVES: To assess the biomechanical performance of a novel bridging plate for treating Rockwood III acromioclavicular joint dislocation. METHODS: A novel bridging plate structure was designed based on CT data from a patient with Rockwood type III acromioclavicular joint dislocation, and a finite element model of the bridging plate-acromioclavicular joint interaction was constructed. The stress and deformation characteristics and biomechanical compatibility of the plate under post-reduction, normal loading, and impact loading conditions were analyzed to evaluate its fixation mechanism and clinical advantages. RESULTS: The stiffness of the bridging system was 27.78 N/mm, close to that of acromioclavicular joint ligaments (26.05 N/mm) and meeting the requirements for flexible deformation. Under normal loading, the maximum stress in the bridging system was 88.29 MPa to sustain physiological activities; under impact loading, the maximum stress reached 480 MPa, and the cable underwent plastic deformation to dissipate energy and effectively buffer local stress concentrations, thereby reducing the risk of rigid bone fractures. The high-stress regions in the bone primarily occurred at the edges of the C1-C4 screw holes. The maximum bone stress was 0.762 MPa under normal loading and 5.963 MPa under impact loading, accounting for 2.86% and 1.66% of the corresponding bolt stresses, respectively. CONCLUSIONS The novel bridging plate is better adapted to biomechanical characteristics of the acromioclavicular joint compared to traditional internal fixation. This fixation system provides sufficient stability while allowing physiological micromotion to facilitate postoperative rehabilitation. Significant flexible deformation can occur at the connection between the fixation ring and the cable, and brittle materials should not be used in this region. The issue of stress concentration at the C1-C4 screw holes requires special attention in its clinical application.
Acromioclavicular Joint/surgery* ; Humans ; Bone Plates ; Biomechanical Phenomena ; Finite Element Analysis ; Joint Dislocations/surgery* ; Fracture Fixation, Internal/methods*

Objective To investigate the clinical effect of glassfiber post with all-ceramic-crown for incisors restoration, providing some references for our clinical application. Methods 82 patients (100 teeth defect) in our department from October,2008 to October, 2009 were divided into group A and group B with 50 incisors in each. Glassfiber post with all - ceramic - crown was used in group A, and metal post with porcelain-fused-to-metal in group B. After one year follow-up, we observed the clinical effect. Results 49 cases were effective and 1 case failed in group A. 42 cases were effective and 8 cases failed in group B.There was statistically significant difference between the two groups. Conclusions Glassfiber post with all-ceramic-crown is better in convenient handling and good colour for incisors compared to metal post with porcelain-fused-to-metal.