The effect of ostrich acellular dermal matrix on keratinized gingival width.

Background: Xenogeneic grafts have gained attention due to advantages in compare of autografts. This study aimed to compare Xeno (ostrich) Acellular Dermal Matrix (XADM) with the free gingival graft (FGG) to increase the width of Keratinized gingiva (KGW) in dogs. Materials and Methods: This split mouth animal study was performed on 10 mixed breed dogs. The upper second premolar sites were randomly selected for grafting by XADM (test) or FGG (control). Measurements of KGW were recorded before surgery, 1, 3, and 6 months after surgery. Biopsies from grafted sites for histologic and histomorphometric evaluations were harvested 6 months after surgery. Data were analyzed by repeated measured, paired samples t-test, and Wilcoxon Signed rank test. P < 0.05 was considered statistically significant. Results: KGW increased in the two study groups after surgery with no significant statistical difference between them at any time intervals (P > 0.05). The graft shrinkage was 23% and 21% for the test and control groups, respectively, without statistically significant difference (P > 0.05). Histomorphometric evaluation showed no significant difference between the two study groups. Foreign body reaction was not seen in any of the study groups. Conclusion: Increased KWG was similar between the two study groups. With regard to FGG limitations, XADM may be assumed as a suitable alternative for FGG. It should be noted that this research was an animal study and clinical trials on human should be performed to approve the efficacy and safety of this material.

The Effect of Low-Level Laser Therapy in Combination with Leukocyte- and Platelet- Rich Fibrin on Bone Regeneration in Rabbits' Calvarial Defects: Histologic and Histomorphometric Studies.

Objective: Bone regeneration is a desired treatment outcome in implant dentistry. The primary goal of the current investigation was to assess the joint effect of low-level laser therapy (LLLT) and leukocyte- and platelet-rich fibrin (PRF) on new bone formation. Materials and Methods: During this experiment study, forty bone defects (8 mm in diameter) were generated in the calvaria of ten New-Zealand white rabbits. defects were filled with autogenous bone defined as the control group, autogenous bone with leukocyte- and PRF (PRF group), autogenous bone and low-level diode laser radiation (LLLT group), and autogenous bone with leukocyte- and PRF and low-level laser radiation (LP group). Laser irradiation was done every second day for 2 weeks after surgery. Five rabbits were randomly selected to be sacrificed on postoperative weeks 4 and 8. On one and two-month post-surgery, histological and histomorphometric parameters including bone formation, fibroblast, and osteoblast were assessed. Results: The histological panel depicted that the ratio of fresh bone formation increased at one-and two-month postsurgery in all treatment groups compared to the control group. The most favorable results were seen in the LP group, followed by the PRF group. Based on the ANOVA test, bone neoformation was statistically significant in the LP group in comparison with the control group (P<0.001). One-month post-surgery, a higher degree of fibroblast was seen in the control group, while the last place was for LP group (118.6 ± 6.9 vs. 24.0 ± 3.2). In the PRF group, the percentage of bone formation was higher than that in the control group (13.2 ± 2.8 vs. 2.0 ± 1.2), but no significant difference when compared to the LP group (13.2 ± 2.8 vs. 19.0 ±.3.8). Conclusion: The combined L-PRF and LLLT was more likely to have a positive effect on accelerating bone regeneration and reducing fibrosis.

Histomorphic Analysis of UV-C Radiation on Osseointegration of Titanium Implants in the Rabbits.

Statement of the Problem: Unsuccessful implant integration leads to pain and implant mobility. Implant photo-functionalization by ultraviolet (UV) light has been suggested as a method that may stimulate osseointegration. Purpose: This study was conducted to analyze the histopathological feature of the titanium implant surface upon treatment with UV-C wave. Materials and Method: In this interventional study, twenty rabbits were enrolled. In the treatment groups, the titanium implants, irradiated earlier with UV-C for four hours laterally, were inserted in one of the femur bones. In the control group, the titanium implants without irradiation were inserted in the other femur bone of the rabbits. After two and four weeks, the animals were sacrificed, and then the samples were histologically and histo-morphometrically analyzed. In addition, the amounts of new bone formation, bleeding, and inflammation were recorded, and the data were subjected to statistical analysis. Results: The results confirmed that UV-C irradiation to titanium implants significantly improved new bone formation (p< 0.001). However, no significant new bone formation was observed between two and four weeks after implant insertion (p< 0.098). Conclusion: The study results showed that irradiating titanium implants with UV-C for four hours significantly improves osseointegration and new bone formation but does not considerably affect inflammation or bleeding around the implant. The study suggests that UV-C radiation can increase the success rate of implant treatment.

Critical-sized bone defects regeneration using a bone-inspired 3D bilayer collagen membrane in combination with leukocyte and platelet-rich fibrin membrane (L-PRF): An in vivo study.

OBJECTIVES: We aim to develop a 3D-bilayer collagen (COL) membrane reinforced with nano beta-tricalcium-phosphate (nß-TCP) particles and to evaluate its bone regeneration in combination with leukocyte-platelet-rich fibrin (L-PRF) in vivo. BACKGROUND DATA: L-PRF has exhibited promising results as a cell carrier in bone regeneration in a number of clinical studies, however there are some studies that did not confirm the positive results of L-PRF application. METHODS: Mechanical & physiochemical characteristics of the COL/nß-TCP membrane (1/2 & 1/4) were tested. Proliferation and osteogenic differentiation of seeded cells on bilayer collagen/nß-TCP thick membrane was examined. Then, critical-sized calvarial defects in 8 white New Zealand rabbits were filled with either Col, Col/nß-TCP, Col/nß-TCP combined with L-PRF membrane, or left empty. New bone formation (NBF) was measured histomorphometrically 4 & 8 weeks postoperatively. RESULTS: Compressive modulus increases while porosity decreases with higher ß-TCP concentrations. Mechanical properties improve, with 89 % porosity (pore size ∼100 µm) in the bilayer-collagen/nß-TCP membrane. The bilayer design also enhances the proliferation and ALP activity. In vivo study shows no significant difference among test groups at 4 weeks, but Col/nß-TCP + L-PRF demonstrates more NBF compared to others (P < 0.05) after 8 weeks. CONCLUSION: The bilayer-collagen/nß-TCP thick membrane shows promising physiochemical in vitro results and significant NBF, as ¾ of the defect is filled with lamellar bone when combined with L-PRF membrane.

Histological Comparison of New Bone Formation Using Amnion Membrane Graft Versus Resorbable Collagen Membrane: An Animal Study.

The purpose of this article was to evaluate the bone induction effects of an amnion membrane-protected graft compared with a collagen membrane-protected graft in the repair of tibial bony defects in dogs. This study was performed using the tibial bone of dogs. After the removal of periosteum, similar holes were made with a 16-mm trephine drill (38 holes in total). For the study group, 10 holes were covered by absorbable collagen and 16 holes by amniotic membrane. In the control group, 12 holes were made and covered by the overlying soft tissue. Tibial bones were exposed after 6 and 12 weeks, and the samples were harvested and histologically processed. New bone formation was evaluated by histomorphometric study. Four Iranian mixed dogs older than 1.5 years were included in this study. The new bone formation was less in the control group when compared with the collagen group ( P = .863). The collagen group showed less bone formation than the amnion group ( P = .194), but this difference was not significant. However, bone formation in the amnion group was significantly more than in the control group ( P = .050). Using the amniotic membrane appears to accelerate bone formation in guided bone regeneration. However, further studies should investigate its clinical impact on bone healing.

Alginate Microcapsules as Nutrient Suppliers: An In Vitro Study.

OBJECTIVES: Alginate, known as a group of anionic polysaccharides extracted from seaweeds, has attracted the attention of researchers because of its biocompatibility and degradability properties. Alginate has shown beneficial effects on wound healing as it has similar function as extracellular matrix. Alginate microcapsules (AM) that are used in tissue engineering as well as Dulbecco's modified Eagle's medium (DMEM) contain nutrients required for cell viability. The purpose of this research was introducing AM in medium and nutrient reagent cells and making a comparison with control group cells that have been normally cultured in long term. MATERIALS AND METHODS: In this experimental study, AM were shaped in distilled water, it was dropped at 5 mL/hours through a flat 25G5/8 sterile needle into a crosslinking bath containing 0.1 M calcium chloride to produce calcium alginate microspheres. Then, the size of microcapsules (300-350 µm) were confirmed by Scanning Electron Microscopy (SEM) images after the filtration for selection of the best size. Next, DMEM was injected into AM. Afterward, adiposederived mesenchymal stem cells (ADSCs) and Ringer's serum were added. Then, MTT and DAPI assays were used for cell viability and nucleus staining, respectively. Also, morphology of microcapsules was determined under invert microscopy. RESULTS: Evaluation of the cells performed for spatial media/microcapsules at the volume of 40 µl, showed ADSCs after 1-day cell culture. Also, MTT assay results showed a significant difference in the viability of sustained-release media injected to microcapsules (P<0.05). DAPI staining revealed living cells on the microcapsules after 1 to 7-day cell culture. CONCLUSIONS: According to the results, AM had a positive effect on cell viability in scaffolds and tissue engineering and provide nutrients needed in cell therapy.

Histological Changes in the Periosteum Following Subperiosteal Expansion in Rabbit Scalp.

PURPOSE: In intraoral bone grafting, tension-free coverage of the recipient site with periosteal flap results in optimal wound closure. Tissue expansion could be a suitable modality to obtain soft tissue in the oral cavity. The aim of this study was to assess the histology of the periosteum after subperiosteal expansion in the rabbit scalp. MATERIALS AND METHODS: In this animal study, 6 rectangular tissue expanders were placed in the skulls of 6 male white New Zealand rabbits; in 6 control rabbits, an incision was made to the periosteum but no expansion was performed. Three months after the surgeries, the rabbits were sacrificed and tissue samples were stained with hematoxylin and eosin and Masson trichrome. RESULTS: The number of osteoblasts, fibroblasts, and blood vessels and the density of collagen fibers were significantly increased in the experimental group compared with the control group (P < .001). CONCLUSIONS: Subperiosteal tissue expansion in the rabbit scalp markedly increased the histologic components of the periosteum involved in bone regeneration.

Effect of sintering temperature rise from 870 to 920°C on physicomechanical and biological quality of nano-hydroxyapatite: An explorative multi-phase experimental in vitro/vivo study.

Hydroxyapatite (HA) is a proper scaffold for bone repair, however, it is not of excellent mechanical properties. Most previous studies on the effect of temperature increases were in vitro and had assessed merely improvements of HA's physicomechanical quality. This in vitro/vivo study investigated the effect of temperature increases from 870 to 920°C on physicomechanical and biological quality of Nano-HA. Forty experimentally produced HA disks sintered at 870 to 920°C were prepared (n=20×2). Disks were subjected to Vickers microindentation test (1 disk from each group divided into 4 quarters), Fourier transform infrared spectroscopy (1 disk), X-ray diffraction (XRD) [1 disk together with non-sintered HA], field emission scanning electron microscopy (FSEM, 1 disk from each group together with non-sintered HA), cell seeding and SEM assessment (2 disks), MTT assay over 4 different time periods (16 quadrants of 4 disks from each group), 6 one-thirds of 2 disks from each group for immunocytochemical (ICC) assay, and 8 disks from each group [as well as non-sintered HA] for the animal study (implantation in 4 sockets in 8 rabbits [32 specimens], histomorphometry, and computerized tomography) over two time periods. Quantitative data were analyzed statistically (α=0.05). Vickers microhardness increased from 63.7±11.9 in the 870 group to 153.4±104.7 in the 920 group (P=0.057). XRD indicated more regular crystal patterns in sintered groups compared to non-sintered nanoHA. FSEM showed larger crystals in the 920 group compared to 870 and non-sintered nanoHA. Expression of osteocalcin, osteonectin, and RUNX2 genes were more visible in ICC samples of the 920HA group. In MTT, cell numbers increased in all groups significantly (P=0.000), with no between-group differences (P>0.3). In rabbit experiments, the extent of 'newly formed bone' increased significantly over time (two-way ANOVA, P=0.000), reaching 39.5%, 46.4%, and 77.5% in the groups non-sintered HA, 870, and 920, respectively. The 920°C-sintered nanoHA induced the highest bone formation (P=0.000). Increasing the temperature of nanoHA sintering from 870 to 920°C can improve its physicomechanical properties and bone formation potential.

Complement factor H and LOC387715/ARMS2/HTRA1 variant's frequencies and phenotypic associations in neovascular age-related macular degeneration, a pilot study.

PURPOSE: To evaluate the frequency of 12 single nucleotide polymorphisms (SNPs) of complement factor H (CFH) and LOC387715/ARMS2/HRTA1 and their association with some of the presenting clinical features of neovascular age-related macular degeneration (AMD). METHODS: In this prospective non-comparative case series forty four naïve patients with neovascular AMD were genotyped using sequencing or Sequenom iPLEX technology. Descriptive tests were used for displaying the magnitude of each allele, gender distribution, and age at diagnosis. Fisher exact test was used to evaluate the correlation between visual acuity (VA) and different alleles. Also Kruskal-Wallis test was used for comparison between age at the time of diagnosis and different alleles. RESULTS: The most frequent SNP among studied patients was rs1061147 with 100% frequency rate. The least common was rs2672598 with a frequency of 52.27%. Only the allele rs800292 of CFH locus on 1q32 was associated with VA better than 20/200 (p value = 0.034). The frequency of this allele was 77.27% (34 patients) in this study. There was no significant association between any of alleles, and VA worse than 20/200(p > 0.05). Fifteen patients had bilateral exudative AMD (34.09%). There was no significant difference between alleles in bilateral neovascular AMD and unilateral disease. Also bilateral and unilateral patients were not different in terms of age, gender or VA (p value: 0.330, 0.764 and 0.456 respectively). There was also no significant association between any of SNPs and bilaterality of disease. CONCLUSION: We designated the frequencies of SNPs of CFH and LOC387715/ARMS2/HRTA1 in neovascular AMD in a sample of Iranian patients. Only the allele rs800292 of CFH locus on chromosome 1q32 was associated with better VA.

Assessment of Surface Markers Derived from Human Periodontal Ligament Stem Cells: An In Vitro Study.

OBJECTIVES: Periodontal tissue regeneration for treatment of periodontal disease has not yet been mastered in tissue engineering. Stem cells, scaffold, and growth factors are the three main basic components of tissue engineering. Periodontal ligament (PDL) contains stem cells; however, the number, potency and features of these cells have not yet been understood. This study aimed to isolate and characterize the properties of PDL stem cells. MATERIALS AND METHODS: In this experimental study, samples were isolated from the PDL of extracted teeth of five patients and then stained immunohistochemically for detection of cell surface markers. Cells were then examined by immuno-flow cytometry for mesenchymal markers as well as for osteogenic and adipogenic differentiation. RESULTS: The isolated cell population had fibroblast-like morphology and flow cytometry revealed that the mesenchymal surface markers were (means): CD90 (84.55), CD31 (39.97), CD166 (33.77), CD105 (31.19), CD45 (32/44), CD44 (462.11), CD34 (227.33), CD38 (86.94), CD13 (34.52) and CD73 (50.39). The PDL stem cells also differentiated into osteoblasts and adipocytes in osteogenic and adipogenic media, respectively. CONCLUSIONS: PDL stem cells expressed mesenchymal stem cell (MSC) markers and differentiated into osteoblasts and adipocytes in osteogenic and adipogenic media, respectively.

Dental pulp stem cells differentiation into retinal ganglion-like cells in a three dimensional network.

The loss of retinal ganglion cells (RGCs) in majority of retinal degenerative diseases is the first seen pathological event. A lot of studies aim to discover suitable cell sources to replace lost and damaged RGCs. Among them dental pulp stem cells (DPSCs) have a great potential of differentiating into neuronal lineages as well as RGCs. Moreover, three-dimensional (3D) networks and its distribution for growing and differentiation of stem cells as much as possible mimic to native tissue holds great potential in retinal tissue engineering. In this study, we isolate DPSCs from rat incisors and validate them with flow cytometry. Briefly, we differentiated cells using DMEM/F12 containing FGF2, Shh and 0.5% FBS into retinal ganglion-like cells (RGLCs) in two conditions; 3D state in biocompatible fibrin hydrogel and two-dimensional (2D) or conventional culture in polystyrene plates. Immuncytochemical and gene expression analysis revealed the expression of Pax6, Atoh7 and BRN3B increased in 3D fibrin culture compared to 2D conventional culture. In combination, these data demonstrate that using 3D networks can resemble near natural tissue properties for effective generating RGCs which used to treat neurodegenerative diseases such as glaucoma.

Cytotoxic Effects and Osteogenic Activity of Calcium Sulfate with and without Recombinant Human Bone Morphogenetic Protein 2 and Nano-Hydroxyapatite Adjacent to MG-63 Cell Line.

OBJECTIVES: The aim of this study was to assess the cytotoxic effects and osteogenic activity of recombinant human bone morphogenetic protein (rhBMP2) and nano-hydroxyapatite (n-HA) adjacent to MG-63 cell line. MATERIALS AND METHODS: To assess cytotoxicity, the 4,5-dimethyl thiazolyl-2,5-diphenyl tetrazolium bromide (MTT) assay was used. Alkaline phosphatase (ALP) activity and osteogenic activity were evaluated using Alizarin red and the von Kossa staining and analyzed by one-way ANOVA followed by Tukey's post hoc test. RESULTS: The n-HA/calcium sulfate (CS) mixture significantly promoted cell growth in comparison to pure CS. Moreover, addition of rhBMP2 to CS (P=0.02) and also mixing CS with n-HA led to further increase in extracellular calcium production and ALP activity (P=0.03). CONCLUSION: This in vitro study indicates that a scaffold material in combination with an osteoinductive material is effective for bone matrix formation.

Mu opioid receptor gene: new point mutations in opioid addicts.

INTRODUCTION: Association between single-nucleotide polymorphisms (SNPs) in mu opioid receptor gene and drug addiction has been shown in various studies. Here, we have evaluated the existence of polymorphisms in exon 3 of this gene in Iranian population and investigated the possible association between these mutations and opioid addiction. METHODS: 79 opioid-dependent subjects (55 males, 24 females) and 134 non-addict or control individuals (74 males, 60 females) participated in the study. Genomic DNA was extracted from volunteers' peripheral blood and exon 3 of the mu opioid receptor gene was amplified by polymerase chain reaction (PCR) whose products were then sequenced. RESULTS: Three different heterozygote polymorphisms were observed in 3 male individuals: 759T > C and 877G > A mutations were found in 2 control volunteers and 1043G > C substitution was observed in an opioid-addicted subject. Association between genotype and opioid addiction for each mutation was not statistically significant. DISCUSSION: It seems that the sample size used in our study is not enough to confirm or reject any association between 759T > C, 877G > A and 1043G > C substitutions in exon 3 of the mu opioid receptor gene and opioid addiction susceptibility in Iranian population.

Evaluation of antitumor activity of a TGF-beta receptor I inhibitor (SD-208) on human colon adenocarcinoma.

BACKGROUND: Transforming growth factor-ß (TGF-ß) pathway is involved in primary tumor progression and in promoting metastasis in a considerable proportion of human cancers such as colorectal cancer (CRC). Therefore, blockage of TGF-ß pathway signaling via an inhibitor could be a valuable tool in CRC treatment. METHODS: To evaluate the efficacy of systemic targeting of the TGF-ß pathway for therapeutic effects on CRC, we investigated the effects of a TGßRI (TGF-ß receptor 1) or TßRI kinase inhibitor, SD-208, on SW-48, colon adenocarcinoma cells. In this work, in vitro cell proliferation was studied by methyl thiazolyl tetrazolium (MTT) and bromo-2'-deoxyuridine (BrdU) assays. Also, the histopathological and immunohistochemical evaluations were conducted by hematoxylin and eosin, and Ki-67 and CD34 markers were stained, respectively. RESULTS: Our results showed no significant reduction in cell proliferation and vessel formation (170 ± 70 and 165 ± 70, P > 0.05) in treated SW-48 cells with SD-208 compared to controls. CONCLUSION: Our data suggested that SD-208 could not significantly reduce tumor growth and angiogenesis in human colorectal cancer model at least using SW-48 cells.

Missense Mutation in Fam83H Gene in Iranian Patients with Amelogenesis Imperfecta.

BACKGROUND: Amelogenesis Imperfecta (AI) is a disorder of tooth development where there is an abnormal formation of enamel or the external layer of teeth. The aim of this study was to screen mutations in the four most important candidate genes, ENAM, KLK4, MMP20 and FAM83H responsible for amelogenesis imperfect. METHODS: Geneomic DNA was isolated from five Iranian families with 22 members affected with enamel malformations. The PCR amplifications were typically carried out for amplification the coding regions for AI patients and unaffected family members. The PCR products were subjected to direct sequencing. The pedigree analysis was performed using Cyrillic software. RESULTS: One family had four affected members with autosomal dominant hypocalcified amelogenesis imperfecta (ADHPCAI); pedigree analysis revealed four consanguineous families with 18 patients with autosomal recessive hypoplastic amelogenesis imperfecta (ARHPAI). One non-synonymous single-nucleotide substitution, c.1150T>A, p. Ser 342Thr was identified in the FAM83H, which resulted in ADHCAI. Furthermore, different polymorphisms or unclassified variants were detected in MMP20, ENAM and KLK4. CONCLUSION: Our results are consistent with other studies and provide further evidence for pathogenic mutations of FAM83H gene. These findings suggest different loci and genes could be implicated in the pathogenesis of AI.

Osteoblastic differentiation of human stem cells derived from bone marrow and periodontal ligament under the effect of enamel matrix derivative and transforming growth factor-beta.

PURPOSE: To increase the understanding of the applicability of biomaterials and growth factors in enhancing stem cell-based bone regeneration modalities, this study evaluated the effects of enamel matrix derivative (EMD) and recombinant human transforming growth factor-beta (rhTGF-ß) on osteoblastic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) as well as human periodontal ligament stem cells (hPDLSCs). MATERIALS AND METHODS: hBMSCs and hPDLSCs were obtained, and identification of stem cell surface markers was performed according to the criteria of the International Society for Cellular Therapy. Each group of stem cells was separately treated with a serial dilution of EMD (10, 50, and 100 µg/mL) or rhTGF-ß (10 ng/mL). Osteoblastic differentiation was examined through in vitro matrix mineralization by alizarin red staining, and mRNA expression of osteopontin and osteonectin was determined by quantitative reverse-transcriptase polymerase chain reaction. hPDLSCs were further assessed for osteocalcin mRNA expression. Stem cells cultured in osteogenic medium were employed as a standard positive control group. RESULTS: In none of the experimental groups were bone-related mRNAs detected subsequent to treatment with EMD for 5, 10, and 15 days. Alizarin red staining on day 21 was negative in EMD-treated BMSC and PDLSC cultures. In rhTGF-ß-supplemented BMSC culture, expression of osteonectin mRNA was demonstrated on day 15, which was statistically comparable to the positive control group. Nevertheless, extracellular matrix mineralization was inhibited in both groups of stem cells. CONCLUSIONS: Within the limitations of this study, it could be concluded that EMD with a concentration of 10, 50, or 100 µg/mL has no appreciable effect on osteoblastic differentiation of BMSCs and PDLSCs. Application of rhTGF-ß increased osteonectin mRNA expression in BMSCs. This finding corroborates the hypothesis that TGF-ß might be involved in early osteoblastic maturation.

The effect of carrier type on bone regeneration of demineralized bone matrix in vivo.

Demineralized bone matrix (DBM) is a bone substitute biomaterial used as an excellent grafting material. Some factors such as carrier type might affect the healing potential of this material. The background data discuss the present status of the field: Albumin as a main protein in blood and carboxymethyl cellulose (CMC) were applied frequently in the DBM gels. We investigated the bone-repairing properties of 2 DBMs with different carriers. Bone regeneration in 3 groups of rat calvaria treated with DBM from the Iranian Tissue Bank Research and Preparation Center, DBM from Hans Biomed Corporation, and an empty cavity was studied. Albumin and CMC as carriers were used. The results of bone regeneration in the samples after 1, 4, and 8 weeks of implantation were compared. The block of the histologic samples was stained with hematoxylin and eosin, and the percentage area of bone formation was calculated using the histomorphometry method. The results of in vivo tests showed a significantly stronger new regenerated bone occupation in the DBM with albumin carrier compared with the one with CMC 8 weeks after the implantation. The 2 types of DBM had a significant difference in bone regeneration. This difference is attributed to the type of carriers. Albumin could improve mineralization and bioactivity compared with CMC.

Reconstruction of human mandibular continuity defects with allogenic scaffold and autologous marrow mesenchymal stem cells.

Mandibular continuity defects occur after tumor resection, maxillofacial injury, or osteomyelitis. In this clinical pilot study, we report a novel method for reconstruction of mandibular continuity defect by in vivo tissue engineering. In 3 patients with critical-size mandibular bone defects, the allogenic mandibular bone scaffold was customized, loaded by ex vivo expanded mesenchymal stem cells, and transplanted into the surgical defect site. According to the bone scintigraphy, vascularized bone was identified in 2 cases. In spiral computed tomography, normal bone healing without significant bone resorption was seen at the 2 viable grafts, but at the failed construction, there was a lack of osteointegration to the adjacent host bone and a higher density in the medullary bone. According to the serial panoramic imaging, the patients with viable bone grafts had normal bone healing, whereas the other patient had progressive overall bone resorption. Our results demonstrate the feasibility of allogenic bone scaffold loaded by mesenchymal stem cells in the reconstruction of mandibular continuity defects. Although long-term results are not yet available, it may be a novel method of reconstruction and a basis for further studies.

Expression of odontogenic genes in human bone marrow mesenchymal stem cells.

OBJECTIVE: Tooth loss is a common problem and since current tooth replacement methods cannot counter balance with biological tooth structures, regenerating natural tooth structures has become an ideal goal. A challenging problem in tooth regeneration is to find a proper clinically feasible cell to seed.This study was designed to investigate the odontogenic potential of human bone marrow mesenchymal stem cells (HBMSCs) for seeding in tooth regeneration. MATERIALS AND METHODS: In this experimental study, three pregnant Sprague Dawley (SD) rats were used at the eleventh embryonic day and rat fetuses were removed surgically using semilunar flap under general anesthesia. The primary mandible was cut using a stereomicroscope. The epithelial and mesenchymal components were separated and the dissected oral epithelium was cultured for 3 days. We used flow cytometry analysis to confirm presence of mesenchymal stem cells and not hematopoietic cells and to demonstrate the presence of oral epithelium. Bone marrow mesenchymal stem cells (BMSCs) and cultured oral epithelium were then co-cultured for 14 days. BMSCs cultured alone were used as controls. Expression of two odontogenic genes Pax9 and DMP1 was assessed using quantitative reverse transcription- polymerase chain reaction (RT-PCR). RESULTS: Expression of two odontogenic genes, Pax9 and DMP1, were detected in BMSCs co-cultured with oral epithelium but not in the control group. CONCLUSION: Expression of Pax9 and DMP1 by human BMSCs in the proximity of odontogenic epithelium indicates odontogenic potential of these cells.

Effect of laminated hydroxyapatite/gelatin nanocomposite scaffold structure on osteogenesis using unrestricted somatic stem cells in rat.

Bone matrix consists of two major phases at the nanoscale: organic and hydroxyapatite. Nanotechnology as a diverse and interdisciplinary area of research has the capacity to revolutionise many areas of applications such as bone tissue engineering. Nanohydroxyapatite/gelatin composite has higher osteoblast attachment and proliferation than micro-sized ones, and shorter culturing period and lower cell seeding density compared to pure gelatin. A nanostructured scaffold was fabricated by three methods for bone repair using nanohydroxyapatite and gelatin as the main components. Its biocompatibility, alizarin red test on the 14th and 21st days, gene expression on the 21st day in in vitro using and histomorphometry after 4 and 8 weeks post-implantation in the rat were investigated. Cultured unrestricted somatic stem cells used for in vitro study showed an excellent level of cell attachment to the scaffold. Cells induced more osteoblast differentiation on the scaffold than in 2D cell culture. Osteoblast differentiation and bone regeneration results of in vitro and in vivo investigation on scaffold were extremely significant, better than control and treatment groups. These effects could be attributed to the shape and size of nanoHA particles and good architecture of the scaffold. The results confirm the feasibility of bone regeneration using synthesised scaffold as a temporary bone substitute.