Background: Due to bone loss, implant placement in the posterior mandible is often impossible without prior augentative procedures. The reconstruction of bone defects with horizontal and vertical components using particulated bone grafts requires the placement of a mechanically stable structure for stabilization of the grafting material. Although titanium‐reinforced membranes and titanium meshes have been shown to be effective in this indication, the necessity of their removal, often in a separate surgical procedure, is seen as a disadvantage. Since the introduction of a new resorbable magnesium metal membrane and fixation screw, a mechanically stable and resorbable system might provide an alternative option for guided bone regeneration (GBR) in the posterior mandible.Case Presentation: A 61‐year‐old patient was presented with large edentulous areas in all posterior regions and requested fixed dentures in Areas 34–36. Tooth 33 was extracted and treated with an immediate implantation of a ceramic implant, whereas Positions 34–36 were treated with a two‐stage approach. The site was augmented horizontally, with a slight vertical component using autologous and allogenic bone and a new completely resorbable magnesium metal membrane and fixation screw. During the initial healing period, the patient reported a tingling sensation at the site of the augmentation. This is an observation that is specific to the magnesium products and is potentially caused by the release of hydrogen gas as the metal degrades and is resorbed. Upon re‐entry at 3 months, it was clinically observed that there was a very dense and vascularized bone that was sufficient for placing two 5.5 × 10 mm ceramic dental implants.Conclusion: A completely resorbable magnesium membrane and fixation screw were able to support the bony regeneration in a large GBR situation in the posterior mandible. Due to the use of a new material for GBR, different clinical observations were made compared to the standard material choices.