Objectives: In clinical cases where a severe horizontal bone deficiency is present, it is very difficult to install implants in the perfect position for achieving optimum aesthetics and functional rehabilitation. The split-crest technique leads to reduced waiting times for installation of implants for maxillary defects of less than 3mm. The cases reported here underwent the split-crest technique with interposition of Bio-Oss biomaterial and were reopened for implant placement after five months. Methods: Patients were selected with a horizontal bone deficiency in the maxilla of 1.6–2.3mm. Both were fit for surgery. The preoperative assessment consisted of blood tests, CT scans and antibiotic prophylaxis and full treatment plans were presented to the patients. Infiltrative terminal anesthesia was applied until satisfactory tissue ischaemia was produced. An incision was made above the crystal with 15c blades and mesiodistal relaxing incisions. After total detachment and bone mucoperiostal exposure, a tag 701 was made with a surgical drill at the cortical level, completed with a metal disc osteotomy. A chisel was used between the markings to achieve total displacement of cortical , to achieve sufficient expansion and an intact nasal spine . Screws were placed at the base of each fracture, preventing vestibular cortical blades from moving during bone maturation. Gaps and remaining spaces were filled with Bio-Oss. Bio-Gide membranes were applied, the flap repositioned and the wound was closed by suturing without tension. Results: CT scans four months postoperatively showed increased bone width of approximately 5.2mm. There were no complications and both patients reported little discomfort after surgery. Both underwent further surgery for implant placement after five months. Primary stability of all implants was achieved and manufacturing the prostheses. Conclusion: The split-crest technique is a feasible option. Using Bio-Oss with a Bio-Gide membrane increased the maxillary bone thickness, which facilitated rehabilitation with dental implants.

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.

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.