Dental prosthesis extraoral indexing and pick‐up technique for mandibular full arch immediate rehabilitation in fibula free flap reconstruction
1. Imaging Obtain CT maxillofacial, CT neck, and CTA images of the lower extremities with 1 mm slices for pre‐surgical planning of the reconstruction and free flap. High‐quality CBCT may also be used. Position the patient in the maxillomandibular relationship of the final prosthetic plan during imaging. For edentulous patients, use a dual scan technique with occlusal rims or an existing denture for planning the prosthetic teeth at the appropriate maxillomandibular relationship. Capture the existing dentition and restorative maxillomandibular relationship with intraoral or laboratory scans of stone models from physical intraoral impressions. If the patient is edentulous, use occlusion rims or an existing denture to facilitate appropriate maxillomandibular records. Design the prosthesis from the pre‐existing dentition or with CAD‐CAM software. 2. Digital surgical planning with a craniofacial plating company Upload images to the software of a craniofacial plating company that partners with a full‐service dental laboratory for digital planning with the surgical and restorative team such as IPS (KLS Martin, Jacksonville, FL) or VSP (Stryker, Kalamazoo, MI). In the virtual surgical planning session, ensure the alignment of the intraoral scan STL images to the CBCT or CT imaging for maintenance of maxillomandibular relationships and improved surface fidelity of the dentition. Position the prosthesis in the planned maxillomandibular relationship to commence planning in a “crown down” approach. Set the neomandible with approximately 17 mm of prosthetic space to accommodate for restorative material, hygiene space, and height of intermediate abutments (Figure ). Plan the implant position into the fibula according to principles of full arch implant dental restoration planning with extra consideration to vertical prosthetic requirements for soft tissue and hygiene space (Figure ). Design the extraoral dental prosthesis positioning and indexing articulator (Figure ). On the upper member, create vertical struts to maintain the maxillomandibular relationship and a positioning attachment to allow for an intimate and reproducible alignment of the full arch dental prosthesis. Design hinges that translate the orientation of the upper member in the sagittal plane to the lower member. Make access channels on the positioning attachment to facilitate accessibility to the screw channels after prosthesis pickup with a dual cure acrylic. Place predictive screw holes on the lower member for reproducibility of the reconstruction plate. With this design, the immediate prosthesis “snaps in” to the upper member of the articulator. The extraoral dental prosthesis position and indexing articulator are additively manufactured by the craniofacial plating company and the dental prosthesis is additively manufactured from the dental laboratory with a biocompatible ceramic nanohybrid photopolymer (Rodin Sculpture; PacDent, Brea, CA). 3. Intraoperative techniques After the surgical team performs the fibula osteotomies and placement of implants (Figure ), place straight intermediate abutments on the dental implants and torque to manufacture specifications. Fit the fibula with implant construct to the defect model, the lower member of the extraoral prosthesis positioning and indexing articulator (Figure ). Adapt custom reconstruction plates to the fibula and leave fixation screws incompletely tightened until the prosthesis is picked up to the temporary cylinders with a dual cure methacrylate‐based acrylic resin (Stellar DC; Taub Products, New Jersey City, NJ). This transfers error from the occlusal relationship of the prosthesis to the neomandible where errors are more readily accommodated and helps prevent an unwanted “roll” of the fibula segment. Seat the immediate prosthesis into the positioning attachment of the upper member with a “snap in” effect to ensure correct positioning of the dental prosthesis (Figure ). Complete seating of the prosthesis can be visualized through the viewing windows of the upper member. Place metal temporary cylinders on the intermediate abutments through access windows of the indexing guide of the upper member and through the widened access channels of the prosthesis. Ensure the temporary cylinders do not contact the prosthesis to minimize errors in passivity of the conversion prosthesis to the intermediate abutments after pick up. Lute the prosthesis to the temporary cylinders with a dual cure acrylic (Stellar DC; Taub Products, New Jersey City, NJ). Fully tighten the reconstruction plate screws and remove the prosthesis for finishing and polishing (Figure ). If immediate load is deemed acceptable by the surgical team, parachute sutures are placed to improve access of the intermediate abutments to the conversion prosthesis (Figure ). Verify the occlusion with articulation paper and adjust as necessary intraoperatively. Tighten prosthetic screws in a counter‐positioning fashion and seal access channels temporarily with polyvinyl siloxane (GI Mask; Coltene Whaledent, Cuyahoga Falls, OH). 4. Post‐operative course Take post‐operative imaging at the first clinic follow‐up to verify positioning and bone height of the neomandible, surgical hardware, and implant placement (Figure ). Occlusal adjustments are performed as necessary. Obtain final records at >6 weeks post‐operatively. Remove the immediate prosthesis for impressions and begin planning for the final prosthesis. Deliver the definitive prosthesis >3 months from the surgical date (Figure ).   Obtain CT maxillofacial, CT neck, and CTA images of the lower extremities with 1 mm slices for pre‐surgical planning of the reconstruction and free flap. High‐quality CBCT may also be used. Position the patient in the maxillomandibular relationship of the final prosthetic plan during imaging. For edentulous patients, use a dual scan technique with occlusal rims or an existing denture for planning the prosthetic teeth at the appropriate maxillomandibular relationship. Capture the existing dentition and restorative maxillomandibular relationship with intraoral or laboratory scans of stone models from physical intraoral impressions. If the patient is edentulous, use occlusion rims or an existing denture to facilitate appropriate maxillomandibular records. Design the prosthesis from the pre‐existing dentition or with CAD‐CAM software.   Upload images to the software of a craniofacial plating company that partners with a full‐service dental laboratory for digital planning with the surgical and restorative team such as IPS (KLS Martin, Jacksonville, FL) or VSP (Stryker, Kalamazoo, MI). In the virtual surgical planning session, ensure the alignment of the intraoral scan STL images to the CBCT or CT imaging for maintenance of maxillomandibular relationships and improved surface fidelity of the dentition. Position the prosthesis in the planned maxillomandibular relationship to commence planning in a “crown down” approach. Set the neomandible with approximately 17 mm of prosthetic space to accommodate for restorative material, hygiene space, and height of intermediate abutments (Figure ). Plan the implant position into the fibula according to principles of full arch implant dental restoration planning with extra consideration to vertical prosthetic requirements for soft tissue and hygiene space (Figure ). Design the extraoral dental prosthesis positioning and indexing articulator (Figure ). On the upper member, create vertical struts to maintain the maxillomandibular relationship and a positioning attachment to allow for an intimate and reproducible alignment of the full arch dental prosthesis. Design hinges that translate the orientation of the upper member in the sagittal plane to the lower member. Make access channels on the positioning attachment to facilitate accessibility to the screw channels after prosthesis pickup with a dual cure acrylic. Place predictive screw holes on the lower member for reproducibility of the reconstruction plate. With this design, the immediate prosthesis “snaps in” to the upper member of the articulator. The extraoral dental prosthesis position and indexing articulator are additively manufactured by the craniofacial plating company and the dental prosthesis is additively manufactured from the dental laboratory with a biocompatible ceramic nanohybrid photopolymer (Rodin Sculpture; PacDent, Brea, CA).   After the surgical team performs the fibula osteotomies and placement of implants (Figure ), place straight intermediate abutments on the dental implants and torque to manufacture specifications. Fit the fibula with implant construct to the defect model, the lower member of the extraoral prosthesis positioning and indexing articulator (Figure ). Adapt custom reconstruction plates to the fibula and leave fixation screws incompletely tightened until the prosthesis is picked up to the temporary cylinders with a dual cure methacrylate‐based acrylic resin (Stellar DC; Taub Products, New Jersey City, NJ). This transfers error from the occlusal relationship of the prosthesis to the neomandible where errors are more readily accommodated and helps prevent an unwanted “roll” of the fibula segment. Seat the immediate prosthesis into the positioning attachment of the upper member with a “snap in” effect to ensure correct positioning of the dental prosthesis (Figure ). Complete seating of the prosthesis can be visualized through the viewing windows of the upper member. Place metal temporary cylinders on the intermediate abutments through access windows of the indexing guide of the upper member and through the widened access channels of the prosthesis. Ensure the temporary cylinders do not contact the prosthesis to minimize errors in passivity of the conversion prosthesis to the intermediate abutments after pick up. Lute the prosthesis to the temporary cylinders with a dual cure acrylic (Stellar DC; Taub Products, New Jersey City, NJ). Fully tighten the reconstruction plate screws and remove the prosthesis for finishing and polishing (Figure ). If immediate load is deemed acceptable by the surgical team, parachute sutures are placed to improve access of the intermediate abutments to the conversion prosthesis (Figure ). Verify the occlusion with articulation paper and adjust as necessary intraoperatively. Tighten prosthetic screws in a counter‐positioning fashion and seal access channels temporarily with polyvinyl siloxane (GI Mask; Coltene Whaledent, Cuyahoga Falls, OH).   Take post‐operative imaging at the first clinic follow‐up to verify positioning and bone height of the neomandible, surgical hardware, and implant placement (Figure ). Occlusal adjustments are performed as necessary. Obtain final records at >6 weeks post‐operatively. Remove the immediate prosthesis for impressions and begin planning for the final prosthesis. Deliver the definitive prosthesis >3 months from the surgical date (Figure ).   Jaw in a day surgeries are increasing in popularity as the psychosocial and quality of life benefits of immediate reconstruction are acknowledged. Advancing technologies allow for a completely digital workflow through high‐quality 3D imaging, intraoral scanning, and virtual surgical planning. They also allow for the development of innovative devices and techniques to reduce intraoperative time, such as the extraoral prosthesis positioning and indexing articulator. This articulator replicates the patient's pre‐surgical maxillomandibular relationship and reliably transfers it to the new prosthesis and neomandible through the design of the hinges and struts of the upper member. The positioning attachment uses a physical index of the patient's planned immediate prosthesis for a “snap in” effect at the time of pick‐up. Indexing to this, rather than the maxillary dentition through the use of a stereolithic model or occlusal splints, minimizes conjecture of the occlusal relationship, error, amount of acrylic debris due to intraoperative prosthesis adjustments, and surgical time. Since the implementation of this extraoral dental prosthesis positioning and indexing articulator at our institution, the need for intraoperative occlusal adjustments has reduced drastically. The complexity of JIAD surgery requires a multidisciplinary approach, often involving teams of surgeons, prosthodontists, oncologists, speech and language pathologists, social workers, nurses, vendor teams, biomedical engineers, and support staff. As subject matter experts on maxillomandibular relationships, prosthetics, materials, and techniques, prosthodontists are critical to the success of same‐day dental rehabilitation. With ever‐advancing technologies, prosthodontists are imperative for dental rehabilitation and uniquely poised to continuously innovate and champion novel technologies and techniques in JIAD surgery.   The design of the novel dental prosthesis positioning and indexing articulator allows for translation of the patient's planned maxillomandibular relationship to the immediate prosthesis and neomandible with high fidelity. This full arch extraoral pick up technique minimizes the need for intraoperative adjustments, lowers the risk of acrylic debris in the surgical site, prevents an unwanted “roll” of the fibula segment, and reduces overall surgical time.   Drs. Andersen and Hammer are consultants for Stryker, Kalamazoo, Michigan. The views expressed in this article are those of the author(s) and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the U.S. Government. 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