title: Biomaterial shell bending with 3D-printed templates in vertical and alveolar ridge augmentation: a technical note.
abstract: OBJECTIVE
  Alveolar ridge and vertical augmentations are challenging procedures in dental implantology. Even material blocks with an interconnecting porous system are never completely resorbed. Shell techniques combined with autologous bone chips are therefore the gold standard. Using biopolymers for these techniques is well documented. We applied three-dimensional (3-D) techniques to create an individualized bending model for the adjustment of a plane biopolymer membrane made of polylactide.
  
  
  METHODS
  Two cases with a vertical alveolar ridge defect in the maxilla were chosen. The cone beam computed tomography data were processed with a 3-D slicer and the Autodesk Meshmixer to generate data about the desired augmentation result. STL data were used to print a bending model. A 0.2-mm poly-D, L-lactic acid membrane (KLS Matin Inc., Tuttlingen, Germany) was bended accordingly and placed into the defect via a tunnel approach in both cases. A mesh graft of autologous bone chips and hydroxylapatite material was augmented beneath the shell, which was fixed with osteosynthesis screws.
  
  
  RESULTS
  The operative procedure was fast and without peri- or postoperative complications or complaints. The panoramic x-ray showed correct fitting of the material in the location. Bone quality at the time of implant placement was type II, resulting in good primary stability.
  
  
  CONCLUSIONS
  A custom-made 3-D model for bending confectioned biomaterial pieces is an appropriate method for individualized adjustment in shell techniques. The advantages over direct printing of the biomaterial shell and products on the market, such as the Xyoss shell (Reoss Inc., Germany), include cost-efficiency and avoidance of regulatory issues.
authors.affiliation: D Implant Institute, Munich, Germany; Extraordinary Professor for Oral & Maxillofacial Surgery, University of Marburg, Germany. Electronic address: draenert@profdraenert.de.
authors.forename: Florian G
authors.initials: FG
authors.lastname: Draenert
authors.affiliation: Private practice for orthodontics, Munich, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Gebhart
authors.affiliation: Department of Prosthodontics, DPU University, Vienna, Austria.
authors.forename: Gergo
authors.initials: G
authors.lastname: Mitov
authors.affiliation: Clinic for Oral & Maxillofacial Surgery, University of Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Neff
mesh_terms: D000540:Alveolar Ridge Augmentation / Q000379:methods*; D001672:Biocompatible Materials; D001863:Bone Screws; D016025:Bone Transplantation / Q000379:methods; D054893:Cone-Beam Computed Tomography; D015921:Dental Implants; D017886:Durapatite; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery; D008567:Membranes, Artificial; D008875:Middle Aged; D011091:Polyesters; D066330:Printing, Three-Dimensional; D011862:Radiography, Panoramic; D014182:Transplantation, Autologous
chemical_list: D001672:Biocompatible Materials; D015921:Dental Implants; D008567:Membranes, Artificial; D011091:Polyesters; C033616:poly(lactide); D017886:Durapatite