Effect of Decompression on Jaw Cystic Lesions Based on Three-Dimensional Volumetric Analysis.

Background and objectives: This study aimed to evaluate the effectiveness of decompression on jaw cysts according to various parameters by volumetric analysis using three-dimensional computed tomography. Materials and methods: Fifty patients who underwent surgical decompression of the jaw cystic lesion were selected, and their preoperative and postoperative computed tomography results between 3 and 27 months were collected. Volumetric analysis was performed to evaluate any differences in the rate of volumetric change according to the sex, age, initial volume of the lesion, duration, location of the lesion, tooth extraction, expansion of the cortical layer, and pathological diagnosis. Multiple linear regression and generalised linear mixed models were used for statistical analyses. Results: The mean reduction rate among all patients was 54.68%. Multiple linear regression analysis revealed that higher reduction rates were associated with a long decompression period, young patient age, and location of the cyst in the posterior maxilla. Generalised linear mixed models revealed that higher reduction rates were associated with a long decompression period and young patient age. Conclusions: Decompression was an effective treatment for reducing the cyst size in all patients. Its effectiveness increased with a long treatment duration, young patient age, and cyst location in the posterior maxilla three-dimensionally.

Combination therapy with BMP-2 and BMSCs enhances bone healing efficacy of PCL scaffold fabricated using the 3D plotting system in a large segmental defect model.

The three-dimensional (3D) plotting system is a rapidly-developing scaffold fabrication method for bone tissue engineering. It yields a highly porous and inter-connective structure without the use of cytotoxic solvents. However, the therapeutic effects of a scaffold fabricated using the 3D plotting system in a large segmental defect model have not yet been demonstrated. We have tested two hypotheses: whether the bone healing efficacy of scaffold fabricated using the 3D plotting system would be enhanced by bone marrow-derived mesenchymal stem cell (BMSC) transplantation; and whether the combination of bone morphogenetic protein-2 (BMP-2) administration and BMSC transplantation onto the scaffold would act synergistically to enhance bone regeneration in a large segmental defect model. The use of the combined therapy did increase bone regeneration further as compared to that with monotherapy in large segmental bone defects.

Decellularized Human Adipose Tissue as an Alternative Graft Material for Bone Regeneration.

BACKGROUND: Tissue engineering approaches to treat damaged bone include various tissue transplants such as autologous, allogeneic, and xenografts. Artificial materials have been widely introduced to meet the demand for graft materials, but insufficiency in supply is still not resolved. In this study, human adipose tissue, easily obtained from the human body, was harvested, and the tissue was decellularized to fabricate a decellularized human adipose tissue matrix (DM) as an alternative graft material. METHODS: Human adipose tissue was obtained via liposuction. The obtained fresh adipose tissue sample was cut into pieces then put into decellularization solution (1% antibiotic-antimycotic solution and 1% phenylmethanesulphonyl fluoride). Lipids were further removed via treatment in isopropanol. The sample was then subjected to another enzymatic digestion and lipid removal processes. The obtained decellularized adipose tissue matrix was lyophilized to form a graft material in disc shape. RESULTS: Decellularization was confirmed by nuclear staining methods and detection of RNA and DNA via PCR. Bone morphogenetic protein 2 (BMP2)-loaded DM showed the ability to form new bone tissue when implanted in subcutaneous tissue. In recovery of a mouse calvarial defect model, BMP2-loaded DM exhibited similar levels of bone tissue regeneration efficiency compared with a well-defined commercial product, BMP2-loaded CollaCote®. CONCLUSION: The DM developed in this study is expected to address the problem of insufficient supply of graft materials and contribute to the treatment of bone defects of critical size as an alternative bone graft material with preserved extracellular matrix components.

Semi-Rigid Fixation Using a Sliding Plate for Treating Fractures of the Mandibular Condylar Process.

Occlusal displacement often occurs after surgery for condylar process fractures because it is difficult to reduce these fractures precisely. However, performing semi-rigid fixation using a sliding plate may overcome this limitation. A retrospective clinical comparison between semi-rigid and rigid fixations was performed. Among 34 patients who had unilateral condylar process fractures, 17 were treated with rigid fixation and the remaining with semi-rigid fixation using a sliding plate. For all patients, panoramic radiographs were collected 1 day and 6 months after surgery. In these radiographs, ramus height and condylar process inclination were measured, and the differences between the fractured and normal sides were assessed. Additionally, the radiographic density of the fracture area was measured. Differences in surgical outcomes and operative times between the two groups and changes in postoperative deviations within each group were analyzed. There was no statistically significant difference in ramus height and condylar process inclination between the two groups at postoperative day 1 and 6 months. Radio-density was observed to be higher in the rigid fixation group, and it increased with time in both groups. The semi-rigid fixation group had a significantly shorter operative time than the other group did. Semi-rigid and rigid fixations showed no differences in terms of effectiveness and outcomes of surgery. In terms of operative time, semi-rigid fixation was superior to rigid fixation.

Microcomputed Tomography and Histological Study of Bone Regeneration Using Tooth Biomaterial with BMP-2 in Rabbit Calvarial Defects.

Our study was aimed to analyze the osteoinductive effect of powdered and block type autogenous bone graft along with bone morphogenetic protein (BMP-2) as compared to synthetic bone graft. Three circular bicortical defects were made in the calvaria of each rabbit and randomly divided into three groups as follows: powdered tooth biomaterial+BMP-2, block tooth biomaterial+BMP-2, and control group: synthetic bone+BMP-2. The samples taken from these defects after 4 and 8 weeks were analyzed histologically along with micro CT analysis. In our study, both powered and block type tooth autogenous bone graft successfully stimulated mesenchymal cells leading to endochondral ossification and bone regeneration. We observed that the powered bone graft material which is acid insoluble especially is preferable as a carrier for BMP-2.

Histomorphometric Evaluation of Socket Preservation Using Autogenous Tooth Biomaterial and BM-MSC in Dogs.

This study is aimed at assessing the dimensional alterations occurring in the alveolar bone after premolar extraction in dogs with histomorphometric and histological analysis. After atraumatic premolar extraction, tooth-derived bone graft material was grafted in the extraction socket of the premolar region in the lower jaws of six dogs in two experimental groups. In the second experimental group, BM-MSCs were added together with the graft. The control was left untreated on the opposite side. After twelve weeks, all six animals were sacrificed. Differences in alveolar bone height crests lingually and buccally, and alveolar bone width at 1, 3, and 5 mm infracrestally, were examined. Histologic study revealed osteoconductive properties of tooth biomaterial. A statistically significant difference was detected between the test and control groups. In the test groups, a reduced loss of vertical and horizontal alveolar bone dimensions compared with the control group was observed. Tooth bone graft material may be considered useful for alveolar ridge preservation after tooth extraction, as it could limit the natural bone resorption process.

Micro-CT and Histomorphometric Study of Bone Regeneration Effect with Autogenous Tooth Biomaterial Enriched with Platelet-Rich Fibrin in an Animal Model.

The aim of this study was to evaluate the potential of tooth biomaterials as bone graft biomaterials for bone healing in rabbits. We prepared tooth biomaterial and platelet-rich fibrin (PRF) to fill the round-shaped defect in the skull of New Zealand white rabbits. These cranial defects were treated with different conditions as follows: group 1, a mixture of tooth biomaterials and platelet-rich fibrin (PRF); group 2, only tooth biomaterials; group 3, only PRF; and group 4, the unfilled control group. Specimens of the filled sites were harvested for analysis with microscopic computerized tomography (micro-CT) and histomorphology at 4 and 8 weeks. As a result of micro-CT, at 4 weeks, the bone volume percentages in groups 1 and 2 were 50.33 ± 6.35 and 57.74 ± 3.13, respectively, and that in the unfilled control group was 42.20 ± 10.53 (p = 0.001). At 8 weeks, the bone volume percentages in groups 1 and 2 were 53.73 ± 9.60 and 54.56 ± 8.44, respectively, and that in the unfilled control group was 37.86 ± 7.66 (p = 0.002). The difference between the experimental group 3 and the unfilled control group was not statistically significant. Histomorphologically, the total new bone was statistically different.

Biosilicated collagen/ß-tricalcium phosphate composites as a BMP-2-delivering bone-graft substitute for accelerated craniofacial bone regeneration.

BACKGROUND: Bioceramic ß-tricalcium phosphate (ß-TCP) is used as a bone-grafting material and a therapeutic drug carrier for treatment of bone defects in the oral and maxillofacial regions due to the osteoconductivity and biocompatibility. However, the low mechanical strength and limited osteoinductivity of ß-TCP agglomerate restrict bone regenerating performance in clinical settings. METHODS: Herein, a biomimetic composite is proposed as a bone morphogenetic protein-2 (BMP-2)-delivering bone graft substitute to achieve a robust bone grafting and augmented bone regeneration. RESULTS: The sequential processes of brown algae-inspired biosilicification and collagen coating on the surface of ß-TCP enable the effective incorporation of BMP-2 into the coating layer without losing its bioactivity. The sustained delivery of BMP-2 from the biosilicated collagen and ß-TCP composites promoted in vitro osteogenic behaviors of pre-osteoblasts and remarkedly accelerated in vivo bone regeneration within a rat calvarial bone defect. CONCLUSIONS: Our multicomposite bone substitutes can be practically applied to improve bone tissue growth in bone grafting applications with further expansion to general bone tissue engineering.

Combined Delivery of Two Different Bioactive Factors Incorporated in Hydroxyapatite Microcarrier for Bone Regeneration.

BACKGROUND: The delivery of growth factors using a carrier system presents a promising and innovative tool in tissue engineering and dentistry today. Two of the foremost bioactive factors, bone morphogenetic protein-2 and vascular endothelial growth factor (VEGF), are widely applied using a ceramic scaffold. The aim of this study was to determine the use of hydroxyapatite microcarrier (MC) for dual delivery of osteogenic and angiogenic factors to accelerate hard tissue regeneration during the regenerative process. METHODS: Two MCs of different sizes were fabricated by emulsification of gelatin and alpha-tricalcium phosphate (α-TCP). The experimental group was divided based on the combination of MC size and growth factors. For investigating the in vitro properties, rat mesenchymal stem cells (rMSCs) were harvested from bone marrow of the femur and tibia. For in vivo experiments, MC with/without growth factors was applied into the standardized, 5-mm diameter defects, which were made bilaterally on the parietal bone of the rat. The animals were allowed to heal for 8 weeks, and samples were harvested and analyzed by micro-computed tomography and histology. RESULTS: Improved proliferation of rat mesenchymal stem cells was observed with VEGF loaded MC. For osteogenic differentiation, dual growth factors delivered by MC showed higher osteogenic gene expression, alkaline phosphatse production and calcium deposition. The in vivo results revealed statistically significant increase in new bone formation when dual growth factors were delivered by MC. Dual growth factors administered on a calcium phosphate matrix showed significantly enhanced osteogenic potential. CONCLUSION: We propose this system has potential clinical utility in providing solutions for craniofacial bone defects, with the added benefit of early availability.

Proteasome inhibition promotes functional recovery after peripheral nerve reperfusion injury.

BACKGROUND: The proteasome degrades NF-kappaB blocking protein (I-kappaB) and activates NF-kappaB that plays as a key transcriptional factor to regulate inflammatory factors that are involved in the tissue reperfusion injury. This study was designed to assess whether the proteasome inhibitor can attenuate peripheral nerve ischemia/reperfusion (I/R) injury and consequently promote motor functional recovery after ischemic insult. METHODS: Rat sciatic nerves were exposed to 2 hour of ischemia followed by various periods of reperfusion. Rats were administered either proteasome inhibitor (bortezomib) or phosphate-buffered saline 30 minutes before reperfusion start. Results were evaluated using a walking track test, and an isolated muscle contraction test, and by muscle weight, and histology. RESULTS: Bortezomib treatment induced an earlier improvement in sciatic functional index and a more rapid restoration of contractile force and wet weight of extensor digitorum longus muscle. Bortezomib reduced early axonal degeneration and promoted regeneration. CONCLUSION: This study indicates that bortezomib; a proteasome inhibitor, is effective at promoting the functional recovery of reperfused peripheral nerve. The proteasome inhibition may play a role as one of the clinical strategy in the peripheral nervous system I/R injury with further understanding its mechanism of action.