Amid friendly autumn weather, the Osteology Foundation welcomed over 300 delegates in Baden-Baden to the 5th National Osteology Symposium from 18-19 September 2015. Scientists and practitioners from Germany, Switzerland and Italy met under the motto Science-based treatment concepts for dental practice. The focus was on practical questions from the daily routine of regenerative dentistry. Scientific evidence as a basis was always taken into account. A total of 34 industry exhibitors sponsored the workshops and the scientific symposium, thus providing participants with high level training as well as information about their products and services. INTENSIVE TRAINING IN 16 WORKSHOPS Friday was the traditional day for practical exercises. The workshops occupied the entire Baden-Baden congress house. Never before had that many workshops been on offer. The wide variety of 16 practical and theoretical workshops attracted close to 200 participants to topics such as extraction socket management, sinus, anterior tooth aesthetics, GBR, interposition, bone splitting, peri-implantitis, soft tissue surgery or the management of failures. The focus was on extensive hands-on training on animal specimens, which could then be applied in practice by the participants. Excellent organisation in advance and a structured approach was reflected by the relaxed atmosphere when welcoming the participants. This was acknowledged by feedback from the participants, stating they had rarely encountered such a stress-free and relaxed further education event at such a high level. PRACTITIONERS FORUM 20 success factors relating to tissue regeneration were presented in the forum for advanced practitioners led by Professor Friedrich Neukam. In front of an audience of some 50 participants, Dr Matthias Mller, legal counsel to the DGMKG, kicked off the session and spoke on current legal issues relating to surgical intervention. Professor Ralf Rler presented measures on the successful treatment of infections and Dr Oliver Brendel discussed the various implant concepts and timings from a prosthetic point of view before the break. In the second half of the session, Dr Gerd Krner provided insights on what needs to be considered when transforming severely periodontally damaged teeth into an aesthetic piece of artwork. Dr Christian Hammcher and Dr Jamal Stein presented their concept on managing peri-implantitis which they had developed and fine-tuned over many years. Dr Raoul Rendchen ended the session with an overview on the consequences of surgical malpositioning of implants. SCIENCE AT A HIGH LEVEL As the Osteology Symposium not only has the aim of bringing science into dental practices, but also wishes to support and enthuse young scientists as well as gaining their interest for the congress, a new highlight was provided by the scientific forum for young physicians which was held in parallel to the practice-oriented events on the Friday. With 23 poster submissions, the interest was overwhelming and by far exceeded initial expectations, so that the jury of the Osteology Foundation had to decide in advance which of the short oral presentations were to be admitted. Moderated by Professor Bilal Al-Nawas, Member of the Expert Council of the Osteology Foundation, Dr Birgit Schfer and Dr Peer Kmmerer held a presentation on the importance and numerous possible stumbling blocks in the field of biomaterials research as well as clinical research. The poster contributions and short presentations covered a variety of subjects, ranging from basic research to pre-clinical as well as clinical research. During the break, the roughly 40 participants had the opportunity of discussing their current priorities and results, including networking between the universities. Other interested delegates to the Osteology Symposium joined the young scientists, and all praised the high scientific level of the forum. TOP LEVEL SCIENTIFIC PROGRAMME Professor Friedrich Neukam opened the symposium on Saturday in the famous Benazet Hall of the Baden-Baden Kurhaus with an overview on the scientific commitment of the Osteology Foundation. A very special moment was the award ceremony of the Osteology Science Award for the best presentations in the scientific forum on the day before. The awards went to Dr Annika Kasten (Rostock) and Dr Martin Heller (Mainz), who each received a voucher for the Osteology Research Academy in 2016. The first third of the symposium under the aegis of Professor Ralf Rler was devoted to the clinical protocols and long-term success rates of treating alveoli. Dr Daniel Thoma gave an impressive presentation on the Zurich Concept, as to how and above all why, the various concepts ranging from immediate to delayed restorations can be differentiated. He also gave an outlook on how pending new developments can adapt the treatment of extraction alveoli even better to the needs of patients. Dr Christiane Kunert-Keil examined the orthodontic movement of teeth following augmentation measures, a topic which is still relatively new in terms of science. According to her experience, the augmented bone should not be too dense, however, following augmentation with Bio-Oss Collagen, loading can already be introduced after only a few weeks, which represents a major gain in time compared with the present standards. The fact that implant dentistry has meanwhile attracted a large field of users, was highlighted by Dr Mario Roccuzzo with his statement that while he used to receive referrals for implant placement, he is now more involved in saving implants. Using case studies, he demonstrated how ridge preservation techniques can be applied initially to facilitate implant positioning in order to achieve a stable outcome in the long term. The second session, headed by Professor Robert Sader, focussed on new insights in block augmentation. Professor Katja Nelson gave a presentation on what autologous blocks from different host regions can achieve and the problems encountered. According to her experience, the iliac crest graft is suited best, but harvesting is not always possible in daily dental practice. Here retromolar bone would be the first choice, but for reasons not yet known precisely, suitability is only limited for ridge preservation. The limitation of options was not only due the materials per se, but also due to the experience of surgeons. Professor Becker explained the main difference between allogenic and xenogenic bone replacement materials and presented the various studies his working group had conducted with blocks over the past years. He underlined that useful alternatives to autologous blocks could exist, if the choice of materials and technique were adapted to the biological limitations. Problems with dehiscences and infections usually occurred through over-contouring. However, as the time required for the complete reconstruction of autologous blocks takes approximately seven years, it remains necessary to conduct long-term studies with biomaterials as nobody so far knows how the alternative materials behave in the long term if an infection occurs. Professor Massimo Simion discussed the pros and cons of autologous and xenogenic blocks compared to bone chips and granules and demonstrated their areas of use as well as their limitations. Although block augmentation tends to show high stability in part, one can observe non-vital areas histologically after several years, whereas chips tend to vascularise rapidly as a rule and the graft contains considerably more vital bone. In the third part of the symposium, Professor Friedrich Neukam approached the topic of cross-border augmentation and avoiding errors before they occur. Professor Bilal Al-Nawas presented numerous cases at the edge of the abyss for iatrogenic-caused failures, for example due to incorrectly positioned or dimensioned implants, as well results following overload of the regenerative potential. According to the current guidelines and risk classifications, there are groups which can be well predicted in dental practice, groups which are questionable, and groups which should better not be included in the planning of augmentation therapies. In many cases, a lot can be gained if major augmentation is avoided and by proceeding step by step to keep the risks low. Professor Torsten Reichert concurred. His presentation focussed on patient-related factors which could lead to failure. One of the risks being, that various pre-existing disorders and treatments may have affected bone metabolism over the years or were, in part, not diagnosed at all. Often however, there was hardly any evidence which prohibited implantation in such situations. Dr Michael Stimmelmayr focussed on complications relating to soft tissue, for example, lacking keratinising gingiva, scarring due to incorrect incision, volume loss due to graft necrosis, or lacking bone foundation for the soft tissue. In terms of soft tissue management, there is often a lack of necessary experience or insufficient education. Success factors for soft tissue management include patient selection, good compliance, appropriate pre-treatment and oral hygiene, extensive patient education and atraumatic surgical techniques. See all photos from the event

Objectives: The objective of this study was compare the osteogenic differentiation potential and mineralisation of STRO-1-positive selected mesenchymal stem cells derived from human tooth germ (hTGSCs) with a heterogeneous hTGSC population, and to determine whether a minor cell subpopulation is more committed to osteogenic differentiation. Methods: Human TGSCs were isolated from dental follicle and apical papilla tissues of impacted tooth germs of third molars from volunteers aged 13–20 years. Cells were expanded and characterised by flow cytometric analysis with CD34, CD45, CD105, CD90, CD44, CD14 and CD117 antigens. Following surface-antigen profiling, STRO-1 antigen, defining a mesenchymal stem cell subpopulation, was used for cell selection with flourescence-activated cell sorting (FACS). Three cell populations (STRO-1 positive, STRO-1 negative, and unsorted) were tested for their ability to differentiate towards osteoblast-like phenotype in osteogenic medium and standard culture medium. Cultures were analysed for cell proliferation (MTS assay and protein assay) and alkaline phosphotase (ALP) activity on days 1, 4, 7, 14 and 21; calcium deposition and gene expression of runx2, osteocalcin and osteonectin with real-time polymerase chain reaction (RT-PCR) on days 7, 14 and 21. Mineralisation and cell phenotype were further screened with Von Kossa staining and confocal microscopy on days 7, 14 and 21. Statistical analysis was made with SPSS Statistics 22[tm]. Kruskal Wallis and Mann–Whitney U tests were applied and a p value of Results: Flow cytometry analysis of passage 3 (p3) hTGSCs showed positivity for CD44, CD90 and CD105, and negativity for CD14, CD45, CD34 and CD117. A total of 11% of p3 hTGSCs were sorted as STRO-1-positive and 24% as STRO-1-negative. In STRO-1-positive cells, osteogenic groups showed significantly higher calcium content than the controls on days 7, 14 and 21. In STRO-1-negative and unsorted cells, the osteogenic groups showed significantly higher calcium content on days 14 and 21 compared to controls. Calcium deposition was not significantly different in osteogenic cell groups in on days 7, 14 and 21. Calcium content seemed to increase in all cell groups from day 7 to day 21. In osteogenic groups, ALP activity of unsorted cells was significantly higher than that of STRO-1-positive and STRO-1-negative groups on days 7, 14 and 21, suggesting a faster rate of osteogenic differentiation in this group, whereas there was no statistical difference between groups on day 21. Activity of ALP was lowest in all groups on day 7 and increased on days 14 and 21. Osteocalcin was expressed in all groups, with no significant difference between them. Osteonectin was highly and significantly expressed in all osteogenic groups on day 7, which is consistent with the findings for ALP and calcium deposition, suggesting that mineralisation was initiated on day 7. Runx2 was downregulated from day 7 to 14. There were no significant differences in the expression of late and early markers of mineralisation in all osteogenic cell groups. Conclusion: Human TGSCs are a novel stem cell source without ethical issues that can be obtained from routine dental treatments. These results suggest they have a high capacityfor osteogenic differentiation. Selecting groups based on STRO-1 negativity or positivity offers no advantages over unsorted cells, but other osteogenic markers might be allow selection of more sensitive osteogenic subpopulations from hTGSCs.