Newly designed retentive posts of mandibular reconstruction plate in oral cancer patients based on preliminary FEM study

BACKGROUND: The reconstruction of a large mandibular defect poses a challenging issue in oral cancer ablation surgery. One popular option for mandibular continuity reconstruction after tumor resection involves the use of a reconstruction plate (R-plate), which maintains space and contour without bone harvesting. An R-plate, however, cannot provide final functional loading rehabilitation with implants or dentures. METHODS: We suggest a new method of functional mandibular reconstruction using retentive posts and an upper prosthesis. The finite element method (FEM) was used to optimize the design. Surgery was needed to adapt the retentive posts. Prosthodontic procedures were required for the upper prosthesis. RESULTS: Eight patients were treated with retentive posts and prostheses. All patients underwent wide resections of the mandible, and reconstruction with an R-plate and microvascular soft tissue transfer. We adapted the retentive posts on an R-plate and fabricated the upper prostheses with a flexible denture or a fixed resin prosthesis. Finally, the patients had functional rehabilitation, which restored proper mastication. CONCLUSIONS: The retentive posts of the R-plate and upper prosthesis allow functional dental rehabilitation without the need for a bone graft. Virtual simulation using FEM will help to design and optimize the retentive posts. Two or three regular size posts are suitable for the quadrant jaw. This first preliminary step will allow improved patient-specific retentive post designs in the near future.