Objectives: Distraction osteogenesis is based on the separation of two vital bone segments and careful distraction after initial formation of callus. A callus between a titanium surface and surrounding bone (“jumping gap regeneration“) might also be eligible for expansion, providing a significantly less-invasive method of distraction osteogenesis. The aim of this pilot study was to evaluate the elevation of a thin HA-coated titanium plate and subsequent callus distraction beneath the titanium. Methods: After gaining approval of the local ethics committee of the University Hospital of Cologne and authorisation by the Federal Institute for Drugs and Medical Devices (BfArM, Bonn, Germany), 10 healthy patients with a vertical bone defect of the posterior maxilla or mandible (two bilateral) were consecutively enrolled. Mucoperiosteal flap elevation was performed, and HA-coated titanium plates (Bonehill Type Zä/® prototypes 14x7mm or 18x8 mm) were inserted 1–2mm away from the underlying bone, by fixing to adjacent teeth using individual bridges. Soft tissue was thickened up beneath the periosteum using a 1-mm collagen matrix (Mucodermä/®) and closed using single mattress sutures. The callus-forming phase was 7–10 days. Membranes were then elevated 0.70mm per day until the desired individual augmentation heights of 4–8 mm were reached. After 4–8 months‘ consolidation, the titanium plates were removed and bone core biopsies harvested in preparation of the implant bed. Conventional radiographs were taken at baseline, after plate insertion, and after the healing periods. Results: Initial healing was uneventful in all cases, with 8 of 12 augmented areas showing sufficient vertical bone formation at the end of the consolidation period. Implants were placed as planned, and histological evaluation showed excellent bone formation with physiological microarchitecture of the bone trephines. One site showed complete reduction of the initially achieved augmentation height based on insufficient retention; in other cases there were trauma-related soft tissue perforations with subsequent removal. In the successful cases, radiographs taken after 4-months‘ consolidation showed initial mineralisation of augmented areas, with increasing radiodensity up to 8 months. At implant uncovering, bone levels were stable radiologically and clinically in both vertical and horizontal dimensions. Conclusions: Given the limitations of this pilot study, we conclude that this novel technique of distraction osteogenesis using HA-coated titanium plates in distance to the underlying bone leads to predictable vertical bone regeneration; this is a proof of concept. It also offers a minimally invasive alternative for vertical ridge augmentation in severely resorbed jaws. A trial based on parallel inclusion of a higher number of patients in a multicentre setting using a device with an internal distraction mechanism, has now begun yielding data on new applications.

Objectives: Mesenchymal stem cells are considered to have a positive impact on tissue regeneration, but they require many manipulations and invasive procedures, such as cell harvesting from bone marrow. This study aimed to evaluate a protocol for using smart blood concentrate in the form of injectable platelet rich fibrin (i-PRF) provides platelets, inflammatory cells and considerable quantities of mesenchymal stem cells from a simple blood withdrawal procedure with a short spin time. Methods: Autologous blood was withdrawn and centrifuged in specific i-PRF tubes at a very low speed for a short time, producing a supernatant of i-PRF. After flow cytometric analysis, specific markers (CD34–, CD45–, CD44+, CD73+, CD90+, CD105+) were applied to detect mesenchymal stem cells. The supernatant was injected into human knee and temporomandibular (TMJ) joints and in sites for soft tissue and bone regeneration within the oral cavity in a total of 40 patients suffering from TMJ and knee joint disorders. Results: Numerous mesenchymal stem cells (0.4–2.0% of total cells) were present in the supernatant. They were cultured in in mono-culture and co-culture with other mesenchymal cells, such as osteoblasts, fibroblasts and endothelial cells. Injection into a graft included clotting of granulesin 1 minute and produced a solid bone graft without any granule mobility (sticky bone graft). Six injections resulted in cartilage regeneration in 10 patients and significant pain relief was achieved in 10 with TMJ dysfunction. In the other 20, better soft tissue and bone regeneration was achieved compared with control groups who received bone substitute and collagen-based materials without i-PRF. Conclusions: This simple protocol may lead to new clinical applications of stem cells for tissue regeneration. The presence of stem cells within the inflammatory milieu might optimise synergy between mesenchymal stem cells and inflammatory cells for soft tissue and bone regeneration.