OBJECTIVE: To assess the possibility of vertical alveolar ridge augmentation by means of activation of the periosteum.
METHODS: Six adult male Beagle dogs were used for the study. All premolars and first molars were extracted, and one vertical saucer-shaped bony defect was created on each side of the mandible. After 3 months of healing, full-thickness muco-periosteal flaps were elevated, and one distraction device was placed on each side of the mandible. The distraction plate was left submerged, and the activation mechanism connected to the distraction rod was exposed intra-orally. The protocol of periosteal activation (PP: periosteal \'pumping\') was initiated after a latency of 7 days. The alternation of activation and relaxation at the rate of 0.35 mm/12 h during 5 days was followed by the sole activation of 0.35 mm/12 h for 5 days (PP group). Devices were left inactivated on the contralateral control side of the mandible (C group). All animals were euthanized after 8 weeks of consolidation. Samples were analysed histologically and by means of micro-CT.
RESULTS: New mature lamellar bone was formed over the pristine bone in all groups. More intensive signs of bone modelling and remodelling were observed in the PP group compared to the C group. Mean new bone, bone marrow, connective tissue and total volumetric densities were greater in the PP group (p < 0.001, p = 0.001, p = 0.003 and p < 0.001, respectively). No differences were observed in the relative area parameters. Total tissue volume and bone volume were higher in the PP group (p = 0.031 and p = 0.076, respectively), while the bone mineral densities were higher in the C group (p = 0.041 and p = 0.003, respectively). Trabecular number, trabecular thickness and trabecular separation values were similar between the two groups.
CONCLUSIONS: Regeneration of vertical alveolar bone ridge defects may be enhanced by activation of the periosteum, without the application of bone grafting materials.

BACKGROUND: Periosteal expansion (PEO) results in the formation of new bone in the space created between existing bone by expanding the periosteum. PEO has already been performed on rabbit parietal bone and effective new bone formation has been demonstrated. In this study, the utility of a polyethylene terephthalate (PET) membrane as an activator was evaluated in the more complex morphology of the mandible.
METHODS: A PET membrane coated with hydroxyapatite (HA)/gelatine was placed in the rabbit mandibular bone at lower margin of mandibular molar region underneath periosteum, and screw-fixed. In the experimental group, the membrane was bent and screw-fixed along the lateral surface of the bone, with removal of the outer screw after 7 days followed by activation of the membrane. The experimental group was divided into two subgroups: with and without a waiting period for activation. Three animals were euthanized at 3 weeks and another three at 5 weeks postoperatively. Bone formation was assessed using micro-CT as well as histomorphometric and histological methods.
RESULTS: No PET membrane-related complications were observed. The area of newly formed bone and the percentage of new bone in the space created by the stretched periosteum did not significantly differ between the control and experimental groups. However, in the experimental group a greater volume was present after 5 weeks than after 3 weeks. Histologically, bone formation occurred close to the site of cortical bone perforation, with many sinusoidal vessels extending through the perforations in the new bone into the overlying fibrous tissue. Inflammatory cells were not seen in the bone.

This study investigates the efficacy of a collagen membrane as a substitute for autologous periosteum in atelocollagen-assisted autologous chondrocyte implantation (ACI) using J-TEC autologous cultured cartilage (JACC®). Sixty-nine patients with knee joint chondral defects underwent ACI using JACC®-34 with periosteum-covered ACI (P-ACIs) and 35 with collagen-covered ACI (C-ACIs). Clinical outcomes were compared through patient-reported measures, International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) scores at second-look arthroscopy one year postoperatively, and adverse event incidence. Postoperative subjective scores significantly improved up to two years, with no significant differences between P-ACI and C-ACI groups. However, C-ACI exhibited a lower adverse event rate (p = 0.034) and significantly higher ICRS CRA scores (p = 0.0001). Notably, C-ACI outperformed P-ACI in both femoral condyle and trochlea assessments (p = 0.0157 and 0.0005, respectively). While clinical outcomes were comparable, the use of a collagen membrane demonstrated superiority in ICRS CRA during second-look arthroscopy and adverse event occurrence.

Limb lengthening relies on the process of distraction osteogenesis. The active periosteal bone formation has been detected in clinical practice with a lengthening and then nail (LATN) technique but has not been confirmed by experimental studies to date. The aim of this study is to compare the tissue regeneration of the distraction regenerate during tibial lengthening in rabbits using a LATN technique. This study was performed on 54 mature rabbits of the Soviet Chinchilla breed, which were divided into three groups of 18 animals. In group 1 (control), the tibia was lengthened in an external fixator. In group 2, the LATN technique was modeled and in group 3, lengthening over nail (LON) was modeled. The total duration of the experiment was 45 days. On the 10th, 15th, 20th, 30th, and 45th day X-ray, computed tomography and morphological studies were performed. In the experimental groups (2 and 3), a more pronounced periosteal bone formation in the area of regenerate was noted when compared to group 1. In group 2 (LATN), wide cortical plates were formed from the intermediate and periosteal areas. In this group, the maximum densitometric density values were noted. Endosteal bone formation was preserved in all groups. The LON and LATN techniques, when compared with the classical Ilizarov lengthening, do not demonstrate any deficiency in the tissue regeneration of the bone tissue at the regenerate sites. The most powerful bone structures are formed with the sequential use of the external fixation and nailing (LATN).

UNASSIGNED: Soft tissue plays an important role in stabilizing the hinge point for osteotomy around the knee. However, insufficient data are available on the anatomic features of the soft tissue around the hinge position for lateral closing-wedge distal femoral osteotomy (LCWDFO).
UNASSIGNED: To (1) anatomically analyze the soft tissue around the hinge position for LCWDFO, (2) histologically analyze the soft tissue based on the anatomic analysis results, and (3) radiologically define the appropriate hinge point to prevent unstable hinge fracture based on the results of the anatomic and histological analyses.
UNASSIGNED: Descriptive laboratory study.
UNASSIGNED: In 20 cadaveric knees (age, 82.7 ± 7.8 years; range, 60-96 years), the soft tissue of the distal medial side of the femur was anatomically analyzed. The thicknesses of the periosteum and direct insertion of the adductor tendon (AT) were histologically examined and measured using an electron microscope. The thickness of the periosteum was visualized graphically, and the graph of the periosteum and radiograph of the knee were overlaid using image editing software. The appropriate hinge position was determined based on the periosteal thickness and attachment of the AT.
UNASSIGNED: The mean thickness of the periosteum of the metaphysis was 352.7 ± 58.6 µm (range, 213.6-503.4 µm). The overlaid graph and radiograph revealed that the thickness of the periosteum changed at the part corresponding to the transition between the diaphyseal and metaphyseal ends of the femur. The mean width of the AT attached to the distal medial femur from the adductor tubercle toward the distal direction was 7.9 ± 1.3 mm (range, 6.3-9.7 mm).
UNASSIGNED: Results indicated that the periosteum and AT support the hinge for LCWDFO within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle.
UNASSIGNED: When the hinge point is located within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle, these soft tissues work as stabilizers, and there is no risk of cutting into the joint space.

OBJECTIVE: To introduce a modified guided bone regeneration (GBR) technique using intact periosteum and deproteinized bovine bone mineral (DBBM) for peri-implant augmentation and compare the clinical outcomes with those of conventional GBR.
METHODS: Patients who received peri-implant augmentation in posterior sites between 2015 and 2021 were reviewed in this study. Group A was treated with a modified GBR technique, and Group B was treated with conventional GBR. For group comparison, propensity score matching was performed with a sensitivity analysis. The implant survival rate, dimensional changes in hard tissue, marginal bone loss (MBL), and peri-implant parameters were evaluated.
RESULTS: In total, 114 implants from 98 patients were included. The implant survival rates were 95.74% in Group A and 95.00% in Group B during the follow-up period. At 6 months, the median horizontal thickness was recorded at 0.87 mm (IQ1-IQ3 = 0.00-1.75 mm) in Group A, exhibiting a relatively lower value compared to the corresponding measurement of 0.98 mm (IQ1-IQ3 = 0.00-1.89 mm) in Group B (p = .937). Vertical height displayed no statistically significant intergroup difference between the two groups (p = .758). The mean follow-up period was 25.83 ± 12.93 months after loading in Group A and 27.47 ± 21.29 months in Group B (p = .761). MBL and peri-implant parameters were comparable between the two groups.
CONCLUSIONS: Within the limitations of this study, the modified GBR technique using intact periosteum and DBBM grafting might be a viable alternative to correct bone defects around implants in molar and premolar sites.

OBJECTIVE: To radiographically evaluate the effect of intact periosteum in guided bone regeneration (GBR) for the treatment of peri-implant ridge defects in posterior region.
METHODS: Twenty-eight patients who satisfied the criteria were included in this study. Buccal dehiscence defects were regenerated using demineralised bovine bone mineral (DBBM). Subjects were divided into two groups: the control group (conventional GBR, buccal trapezoidal flap and DBBM with collagen membrane coverage, n = 14) and the test group (modified GBR, buccal pouch and DBBM with collagen membrane coverage, n = 14). CBCT images obtained immediately after and 3 to 7 months following GBR were used to assess buccal bone thickness (BBT) at a level of 0, 2, 4 and 6 mm below the implant platform.
RESULTS: Immediately after surgery, BBT at 0 mm and 2 mm below the implant platform presented a significant difference between the two groups (P < 0.05) with significantly thicker buccal bone in the control group in terms of BBT-0 (3.83 ± 1.01 mm) and BBT-2 (4.88 ± 1.15 mm) than in the test group (2.33 ± 0.66 mm and 3.60 ± 1.10 mm, P = 0.000 and P = 0.008, respectively). After 3 to 7 months of healing, the BBT at all levels showed no significant difference between the two groups (P > 0.05), but more bone graft resorption (BBR) in the control group in terms of BBR-0 (2.45 ± 1.14 mm), BBR-2 (2.09 ± 0.94 mm) and BBR-0% (65.37% ± 26.62%) than the test group (BBR-0 1.07 ± 0.51 mm, P = 0.001; BBR-2, 1.22 ± 0.63 mm, P = 0.008; BBR-0% 45.70% ± 15.52%, P = 0.024).
CONCLUSIONS: In the short term, all treatment modalities achieved similar coronal BBT and the intact periosteum had a positive effect on keeping ridge dimensions even.

The periosteum is a thin tissue surrounding each skeletal element that contains stem and progenitor cells involved in bone development, postnatal appositional bone growth, load-induced bone formation, and fracture repair. BMP and TGFβ signaling are important for periosteal activity and periosteal cell behavior, but thorough examination of the influence of these pathways on specific cell populations resident in the periosteum is lacking due to limitations associated with primary periosteal cell isolations and in vitro experiments. Here we describe the generation of a novel periosteum-derived clonal cell (PDC) line from postnatal day 14 mice and use it to examine periosteal cell behavior in vitro. PDCs exhibit key characteristics of periosteal cells observed during skeletal development, maintenance, and bone repair. Specifically, PDCs express established periosteal markers, can be expanded in culture, demonstrate the ability to differentiate into chondrocytes, osteoblasts, and adipocytes, and exhibit an osteogenic response to physical stimulation. PDCs also engage in BMP and/or TGFβ signaling when treated with the activating ligands BMP2 and TGFβ-1, and in response to mechanical stimulation via fluid shear. We believe that this PDC line will be useful for large-scale, long-term experiments that were not feasible when using primary periosteal cells. Anticipated future uses include advancing our understanding of the signaling interactions that occur during appositional bone growth and fracture repair and developing drug screening platforms to discover novel growth and fracture healing factors.

An experimental in vivo model has been developed on the rabbit mandible to study reparative regeneration of alveolar bone after intercortical split osteotomy and the role of the periosteum in the process of reparative osteogenesis. The peculiarity of this model is fixation of the periosteum over the reconstruction zone, which allows preserving the bone block displaced during surgery and leads to the formation of an organotypic structure of the regenerate with cortical and spongy bone.

OBJECTIVE: Minipigs present advantages for studying oral bone regeneration; however, standardized critical size defects (CSD) for alveolar bone have not been validated yet. The objectives of this study are to develop a CSD in the mandibular alveolar bone in Aachen minipigs and to further investigate the specific role of periosteum.
METHODS: Three female Aachen minipigs aged 17, 24, and 84 months were used. For each minipig, a split-mouth design was performed: an osteotomy (2 cm height × 2.5 cm length) was performed; the periosteum was preserved on the left side and removed on the right side. Macroscopic, cone beam computed tomography (CBCT), microcomputed tomography (µCT), and histological analyses were performed to evaluate the bone defects and bone healing.
RESULTS: In both groups, spontaneous healing was insufficient to restore initial bone volume. The macroscopic pictures and the CBCT results showed a larger bone defect without periosteum. µCT results revealed that BMD, BV/TV, and Tb.Th were significantly lower without periosteum. The histological analyses showed (i) an increased osteoid apposition in the crestal area when periosteum was removed and (ii) an ossification process in the mandibular canal area in response to the surgical that seemed to increase when periosteum was removed.
CONCLUSIONS: A robust model of CSD model was developed in the alveolar bone of minipigs that mimics human mandibular bone defects. This model allows to further investigate the bone healing process and potential factors impacting healing such as periosteum.
CONCLUSIONS: This model may be relevant for testing different bone reconstruction strategies for preclinical investigations.