Similarities and differences between porcine mandibular and limb bone marrow mesenchymal stem cells

ObjectiveResearch has shown promise of using bone marrow mesenchymal stem cells (BMSCs) for craniofacial bone regeneration; yet little is known about the differences of BMSCs from limb and craniofacial bones. This study compared pig mandibular and tibia BMSCs for their in vitro proliferation, osteogenic differentiation properties and gene expression.DesignBone marrow was aspirated from the tibia and mandible of 3–4 month-old pigs (n = 4), followed by BMSC isolation, culture-expansion and characterization by flow cytometry. Proliferation rates were assessed using population doubling times. Osteogenic differentiation was evaluated by alkaline phosphatase activity. Affymetrix porcine microarray was used to compare gene expressions of tibial and mandibular BMSCs, followed by real-time RT-PCR evaluation of certain genes.ResultsOur results showed that BMSCs from both locations expressed MSC markers but not hematopoietic markers. The proliferation and osteogenic differentiation potential of mandibular BMSCs were significantly stronger than those of tibial BMSCs. Microarray analysis identified 404 highly abundant genes, out of which 334 genes were matched between the two locations and annotated into the same functional groups including osteogenesis and angiogenesis, while 70 genes were mismatched and annotated into different functional groups. In addition, 48 genes were differentially expressed by at least 1.5-fold difference between the two locations, including higher expression of cranial neural crest-related gene BMP-4 in mandibular BMSCs, which was confirmed by real-time RT-PCR.ConclusionsAltogether, these data indicate that despite strong similarities in gene expression between mandibular and tibial BMSCs, mandibular BMSCs express some genes differently than tibial BMSCs and have a phenotypic profile that may make them advantageous for craniofacial bone regeneration.     

Maxillary sinus floor augmentation and dental implant placement using dentin matrix protein-1 gene-modified bone marrow stromal cells mixed with deproteinized boving bone: A comparative study in beagles

ObjectiveThe aim of the study was to evaluate the effects of the combined use of dentin matrix protein-1 (DMP1) gene-modified bone marrow stromal cells (BMSCs) and Bio-Oss^® for maxillary sinus floor augmentation (MSFA) implant placement in dogs.Materials and methodsBMSCs were derived from bone marrow of six beagles and cultured. The cells were transduced with a lentiviral vector overexpressing the DMP1 gene and enhanced green fluorescent protein (EGFP) gene (Lenti-DMP1/EGFP) in test group, and with a lentiviral vector encoding EGFP gene (Lenti-EGFP) in control group. Six dogs received sinus augmentations using the bilateral approach with a simultaneous implant placement at each site respectively. At the same concentration, 2 × 10⁷ cells/ml, one sinus was grafted using a mixture of autologous DMP1/EGFP gene-modified BMSCs and Bio-Oss^® (DMP1 group), and the contralateral sinus was grafted with autologous EGFP gene-modified bMSCs and Bio-Oss^® (EGFP group). After a 3 month healing period, bone regeneration and osseointegration were evaluated using histologic and histomorphometric methods.ResultsThe bone-implant contact (BIC) and the bone area fraction in the DMP1 group (BIC: 34.67% ± 8.23%, bone area fraction: 35.16% ± 3.32%) were significantly greater compared with the EGFP group (BIC: 26.06% ± 5.16%, bone area fraction: 20.74% ± 1.63%) (P < 0.05). No significant difference between the residual bone substitute material volume (BSMV) in the DMP1 group (35.86 ± 7.35) and the EGFP group (32.16 ± 9.16) was found in our study (P > 0.05).ConclusionBMSCs modified with the DMP1 gene can be used as an adjunct to Bio-Oss^® to enhance new bone formation and the osseointegration of dental implants in MSFA of dogs.     

Effects of connective tissue growth factor on human periodontal ligament fibroblasts

ObjectiveThe aim of this study was to evaluate the effects of different concentrations of connective tissue growth factor (CTGF) on human periodontal ligament fibroblasts(HPLFs).DesignHPLFs were cultured and identified. Then, different concentrations of CTGF (1, 5, 10, 50, 100 ng/ml) were added to the HPLF culture. Next, CCK-8 assays, alkaline phosphatase (ALP) assays, hydroxyproline determination, alizarin red staining methods, Transwell chambers and real-time PCR methods were applied to observe the effects of CTGF on the proliferation, ALP activity, synthesis of collagen, formation of mineralized nodules and migration. We also studied expression of ALP, fiber link protein (FN), integrin-binding sialoprotein (IBSP), osteocalcin (OC), and integrin beta 1 (ITGB1) mRNA by HPLFs. Statistical significance was assumed if P < 0.05 or P < 0.01.ResultsThe addition of CTGF (1, 5, 10 ng/ml) remarkably promoted the proliferation and collagen synthesis of HPLFs compared with controls. CTGF (1, 5, 10, 50 ng/ml) improved ALP activity of HPLFs, and at all concentrations, CTGF (1, 5, 10, 50, 100 ng/ml) improved the expression of ALP, FN, IBSP and ITGB1 mRNA. In addition, CTGF (1, 5, 10, 50, 100 ng/ml) promoted the migration of HPLFs, which was dose-dependent, with maximal promotion in the 10 ng/ml group (P < 0.05 or P < 0.01).ConclusionsThus, in a certain range of concentrations, CTGF can promote the biological effects, including proliferation, migration and collagen synthesis of HPLFs, to promote the differentiation of HPLFs in the process of osteogenesis.     

Effects of prostaglandin E2 on clonogenicity,proliferation and expression of pluripotent markers in human periodontal ligament cells

Background and objectiveBased on our earlier work on the response of periodontal ligament (PDL) cells to mechanical stress by induction of cyclooxygenase expression and production of prostaglandin PGE₂ that could regulate mineralization of PDL cells, it was hypothesized that PGE₂ had potential effects on PDL stemness. In this study, we aimed to investigate clonogenicity, proliferation and expression of certain pluripotent markers, considered to be characteristics of PDL stemness, in response to treatment with exogenously-added PGE₂.Material and methodsHuman PDL cells were cultured and treated with various doses of PGE₂, and the aforementioned characteristics of PDL stemness were analyzed.ResultsThe clonogenicity and proliferation were significantly enhanced by PGE₂ at low concentrations (0.01, 0.1 and 1 ng/ml; P < 0.05), but only the proliferation was significantly diminished by PGE₂ at a high concentration (100 ng/ml; P < 0.05). Expression of NANOG and OCT4 mRNA and protein was increased by PGE₂ treatment at 0.1 and 1 ng/ml. Consistently, expression of stage-specific embryonic antigen 4, a putative stem cell marker, was significantly augmented by PGE₂ treatment at 1 ng/ml (P < 0.05).ConclusionOur findings suggest that although a high dose of PGE₂ (100 ng/ml) inhibits proliferation of PDL cells, PGE₂ at low doses appears to play a role in the maintenance of PDL stemness.     

Osseointegration of fiber-reinforced composite implants: Histological and ultrastructural observations

ObjectivesThe aim of this study was to evaluate the bone tissue response to fiber-reinforced composite (FRC) in comparison with titanium (Ti) implants after 12 weeks of implantation in cancellous bone using histomorphometric and ultrastructural analysis.Materials and methodsThirty grit-blasted cylindrical FRC implants with BisGMA–TEGDMA polymer matrix were fabricated and divided into three groups: (1) 60 s light-cured FRC (FRC-L group), (2) 24 h polymerized FRC (FRC group), and (3) bioactive glass FRC (FRC–BAG group). Titanium implants were used as a control group. The surface analyses were performed with scanning electron microscopy and 3D SEM. The bone–implant contact (BIC) and bone area (BA) were determined using histomorphometry and SEM. Transmission electron microscopy (TEM) was performed on Focused Ion Beam prepared samples of the intact bone–implant interface.ResultsThe FRC, FRC–BAG and Ti implants were integrated into host bone. In contrast, FRC-L implants had a consistent fibrous capsule around the circumference of the entire implant separating the implant from direct bone contact. The highest values of BIC were obtained with FRC–BAG (58 ± 11%) and Ti implants (54 ± 13%), followed by FRC implants (48 ± 10%), but no significant differences in BIC or BA were observed (p = 0.07, p = 0.06, respectively). TEM images showed a direct contact between nanocrystalline hydroxyapatite of bone and both FRC and FRC–BAG surfaces.ConclusionFiber-reinforced composite implants are capable of establishing a close bone contact comparable with the osseointegration of titanium implants having similar surface roughness.     

In vitro dentine remineralization with a potential salivary phosphoprotein homologue

ObjectiveAdvantages of introducing a salivary phosphoprotein homologue under standardized in vitro conditions to simulate the mineral-stabilizing properties of saliva have been proposed. This study longitudinally investigates the effects of casein, incorporated as a potential salivary phosphoprotein homologue in artificial saliva (AS) solutions with/without fluoride (F) on in vitro dentine lesion remineralization.DesignThin sections of bovine root dentine were demineralized and allocated randomly into 6 groups (n = 18) having equivalent mineral loss (ΔZ) after transverse microradiography (TMR). The specimens were remineralized using AS solutions containing casein 0 μg/ml, F 0 ppm (C₀–F₀); casein 0 μg/ml, F 1 ppm (C₀–F₁); casein 10 μg/ml, F 0 ppm (C₁₀–F₀); casein 10 μg/ml, F 1 ppm (C₁₀–F₁); casein 100 μg/ml, F 0 ppm (C₁₀₀–F₀) or casein 100 μg/ml, F 1 ppm (C₁₀₀–F₁) for 28 days with TMR taken every 7 days.ResultsSurface mineral precipitation, evident in group C₀–F_1, was apparently inhibited in groups with casein incorporation. Repeated measures ANOVA with Bonferroni correction revealed higher ΔZ for non-F and non-casein groups than for their counterparts (p < 0.001). Subsequent multiple comparisons showed that mineral gain was higher (p < 0.001) with 10 μg/ml casein than with 100 μg/ml when F was present in the earlier stages of remineralization, with both groups achieving almost complete remineralization after 28 days.ConclusionCasein is a potential salivary phosphoprotein homologue that could be employed for in vitro dentine remineralization studies. Concentration related effects may be clinically significant and thus must be further examined.     

Influence of tumour necrosis factor alpha on epithelial–mesenchymal transition of oral cancer cells in co-culture with mesenchymal stromal cells

Tumour progression in head and neck squamous cell carcinoma (HNSCC) is influenced by the surrounding stroma and inflammatory cytokines such as tumour necrosis factor alpha (TNF-α). The aim of this study was to test the hypothesis that TNF-α modulates the interactions of HNSCC cell line PCI-13 and bone marrow mesenchymal stromal cells (BMSCs) and influences markers of epithelial–mesenchymal transition (EMT). Following induction with TNF-α, mono- and co-cultures of BMSCs and the established HNSCC cell line PCI-13 were analyzed; protein expression of E-cadherin and vimentin and qRT-PCR expression of Snail, Twist, MMP14, vimentin, E-cadherin, and β-catenin were examined, and changes in cellular AKT signalling were analyzed. TNF-α induced a significant decrease in E-cadherin (64.5 ± 6.0%, P = 0.002) and vimentin (10.4 ± 3.5%, P = 0.04) protein expression in co-cultured PCI-13, while qRT-PCR showed a significant increase in β-catenin (BMSCs P < 0.0001; PCI-13 P = 0.0005) and Snail (BMSCs P = 0.009; PCI-13 P = 0.01). TNF-α also resulted in a down-regulation of AKT downstream targets S6 (38.7 ± 20.9%, P = 0.01), p70S6 (16.7 ± 12%, P = 0.05), RSK1 (23.6 ± 28.8%, P = 0.02), and mTOR (27.4 ± 17.5%, P = 0.004) in BMSC co-cultures. In summary, while reducing the expression of vimentin and AKT-signalling in PCI-13 and BMSC, respectively, TNF-α introduced an inflammatory-driven tumour–stroma transition, marked by an increased expression of markers of EMT.     

β-Tricalcium phosphate promotes cell proliferation,osteogenesis and bone regeneration in intrabony defects in dogs

ObjectiveThis study investigates the effect of the new synthetic bone grafting material, high pure-phase β-tricalcium phosphate (Cerasorb^® M, granule size 500–1000 μm), on the osteogenesis process and proliferation marker in bone marrow stromal cells (BMSCs) and its regenerative effect in the periodontal intrabony defects in dogs.DesignThe effect of Cerasorb^® M (20 and 40 mg ml^?1 for 1 and 2 weeks) on the proliferation rate of BMSCs was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay on the proliferating cell nuclear antigen (PCNA) by immunoblotting and on alkaline phosphatase level by colourimetric assay. The regenerative effect of Cerasorb^® M in the periodontal intrabony defects in dogs was investigated by histological and immunohistochemical analysis after 3 and 6 months of grafting.ResultsIncubation of BMSCs with Cerasorb^® M for 2 weeks led to significant increase in cell proliferation rate, which was associated with increased PCNA. Cerasorb^® M significantly increased the production of alkaline phosphatase as a marker for the osteogenic stromal lineage and for differentiation and bone formation in BMSCs after 2 weeks. In the histological features and immunohistochemical analysis of PCNA of the intrabony defects in dogs augmented with Cerasorb^® M, osteoid tissue with a plate-like structure and cellular mesenchymal proliferation besides osteoid islands joined by bridges were observed after 3 months. Six months after the implantation, the Cerasorb^® M granules were replaced by abundant new plate-like bone besides PCNA-enriched, small, oval-shaped mononuclear cells and multinucleated-giant cells that were attached to newly formed bones. No remains of the Cerasorb^® M granules could be seen after 3 and 6 months with the newly formed plate-like bones and no histological sign of inflammatory reaction or formation of foreign-body granulomas.ConclusionCerasorb^® M may induce cell proliferation via induction of PCNA that may induce early osteogenesis and bone formation. Cerasorb^® M regenerated the bone completely in intrabony defects and that this regeneration was highly associated with PCNA expression in different cell lineage.     

BMP2 and BMP4 variations and risk of non-syndromic cleft lip and palate

ObjectiveNon-syndromic cleft lip with or without cleft palate (CL/P) is one of the most common congenital anomalies and arises from the interaction of environmental and genetic factors. The objective of this study was to investigate the association between the BMP2 (bone morphogenetic protein 2) and BMP4 (bone morphogenetic protein 4) polymorphisms with non-syndromic CL/P to clarify the potential role of these genes in the etiology of CL/P in Iranian population.DesignThe allelic and genotypic frequencies of BMP2 rs235768 A > T and BMP4 rs17563 T > C polymorphisms were determined in 107 unrelated Iranian subjects with non-syndromic CL/P and 186 control subjects using PCR and RFLP methods, and the results were compared with healthy controls. A p-value of <0.05 was considered statistically significant.ResultsThe BMP2 rs235768 AT genotype was significantly higher (P = 0.009, OR = 3, 95% CI = 1.3–7.0) in the CL/P (59.8%) than the control group (33.3%). Similarly, the BMP4 rs17563 TC genotype were significantly higher (P = 0.008, OR = 3.7, 95% CI = 1.4–9.9) in the CL/P (70.0%) than the control group (44.6%).ConclusionThe BMP2 rs235768 A > T and BMP4 rs17563 T > C polymorphisms could be considered as the risk factor for non-syndromic CL/P in Iranian population.     

Comparison of craniofacial morphology,head posture and hyoid bone position with different breathing patterns

ObjectivesThe aim of this study was to evaluate differences in craniofacial morphology, head posture and hyoid bone position between mouth breathing (MB) and nasal breathing (NB) patients.MethodsMouth breathing patients comprised 34 skeletal Class I subjects with a mean age of 12.8 ± 1.5 years (range: 12.0–15.2 years). Thirty-two subjects with skeletal Class I relationship were included in the NB group (mean 13.5 ± 1.3 years; range: 12.2–14.8 years). Twenty-seven measurements (15 angular and 12 linear) were used for the craniofacial analysis. Additionally, 12 measurements were evaluated for head posture (eight measurements) and hyoid bone position (four measurements). Student’s t-test was used for the statistical analysis. Probability values <0.05 were accepted as significant.ResultsStatistical comparisons showed that sagittal measurements including SNA (p < 0.01), ANB (p < 0.01), A to N perp (p < 0.05), convexity (p < 0.05), IMPA (p < 0.05) and overbite (p < 0.05) measurements were found to be lower in MB patients compared to NB. Vertical measurements including SN-MP (p < 0.01) and PP-GoGn (p < 0.01), S-N (p <0.05) and anterior facial height (p < 0.05) were significantly higher in MB patients, while the odontoid proses and palatal plane angle (OPT-PP) was greater and true vertical line and palatal plane angle (Vert-PP) was smaller in MB patients compared to NB group (p < 0.05 for both). No statistically significant differences were found regarding the hyoid bone position between both groups.ConclusionsThe maxilla was more retrognathic in MB patients. Additionally, the palatal plane had a posterior rotation in MB patients. However, no significant differences were found in the hyoid bone position between MB and NB patients.     

Comparison of the properties of human CD146+ and CD146− periodontal ligament cells in response to stimulation with tumour necrosis factor α

ObjectivesPeriodontal ligament stem cells (PDLSCs) can be used in periodontal regeneration. Tumour necrosis factor-alpha (TNF-α) participates in the regulation of cell proliferation, apoptosis, differentiation, and migration. However, whether TNF-α can affect the biological features of PDLSCs is still unclear. The objective of this study was to illustrate the biological effects (proliferation, apoptosis, osteogenesis and migration) of TNF-α on human CD146 positive periodontal ligament cells (CD146+PLDCs) and CD146 negative periodontal ligament cells (CD146?PDLCs).MethodsCD146 ± PDLCs were isolated from human PDLCs and analyzed using a fluorescence-activated cell sorter. The biological effects of TNF-α on CD146 ± PDLCs were evaluated by CCK-8 assay (proliferation), DAPI staining (apoptosis), alizarin red staining and alkaline phosphatase activities assay (osteogenesis), and wounding assay and transwell assay (migration).ResultsCD146+PDLCs, which expressed MSC surface markers CD105, CD90, CD73, CD44, and Stro-1, showed higher proliferative and osteogenic potential than CD146?PDLCs. TNF-α at a dose of 2.5 ng/ml was found to enhance both proliferation and osteogenesis in CD146+PDLCs. At 5 ng/ml, TNF-α promoted proliferation, osteogenesis, and apoptosis in CD146+PDLCs and enhanced osteogenesis in CD146?PDLCs. At 10 ng/ml, TNF-α only aggravated apoptosis in CD146+PDLCs. The migratory ability of both CD146+PDLCs and CD146?PDLCs was not altered by TNF-α.ConclusionsCD146+PDLCs were subpopulation of MSC. It showed greater proliferative and osteogenic potential than CD146?PDLCs. At low concentration, TNF-α was beneficial to CD146+PDLCs on proliferation and osteogenesis, and at high concentration it was detrimental. CD146?PDLCs were found to be less sensitive to TNF-α.     

Initial bone regeneration around fenestrated implants in Beagle dogs using basic fibroblast growth factor–gelatin hydrogel complex with varying biodegradation rates

PurposeThe purpose of this study was to compare the effectiveness of fast and slow biodegradation of basic fibroblast growth factor (bFGF)–gelatin hydrogel complex on bone regeneration around fenestrated implants as a new augmentation drug delivery system.MethodsNine titanium implants (3.3 mm diameter and 10 mm length) were placed into the edentulous areas of the mandibles of three adult beagle dogs with four screws exposed at the upper buccal side. The effectiveness of bFGF–gelatin hydrogel complexes of varying degradation types used to cover implant screws without membrane were compared with 1 μg and 10 μg bFGF–98 wt% gelatin as the fast degradation type and 10 μg bFGF–95 wt% gelatin as the slow degradation type. After 4 weeks, bone regeneration around the screws was evaluated histologically and histomorphometrically.ResultsWith use of 10 μg bFGF, regenerated bone around exposed screws was clearly seen in both the fast and slow degradation type groups. In contrast, little bone formation was seen in the fast degradation-type group with 1 μg bFGF. Height of regenerated bone for the slow degradation-type complex group was significantly greater than for the fast degradation-type group with 1 μg bFGF (P < 0.05).ConclusionThese results suggest that use of slow degradation-type bFGF–gelatin hydrogel complex may accelerate bone regeneration around fenestrated implants at an early stage of bone regeneration.     

Human neutrophil peptide-1 affects matrix metalloproteinase-2, -8 and -9 secretions of oral squamous cell carcinoma cell lines in vitro

ObjectivesThe present study aimed to investigate the effect of HNP-1 on the matrix metalloproteinase (MMP)-2, -8 and -9 secretions of two oral squamous cell carcinoma (OSCC) cell lines (UT-SCC-43A and UT-SCC-43B).DesignIn all experiments, the two OSCC cell lines were incubated with graded concentrations (0, 1, 5, and 10 μg/ml) of HNP-1 for 24 and 48 h. Cell viability was measured using a colorimetric proliferation test and cell death was analyzed with a colorimetric cytotoxicity detection kit. Enzyme activity of MMP-2 and MMP-9 was detected by using gelatin zymography, and molecular weight forms of MMP-8 were determined by Western-blot and a densitometric quantitation method.ResultsBoth cell lines showed a significant increase in LDH toxicity at 24 h (UT-SCC-43A: p = 0.005 & UT-SCC-43B: p = 0.014). Reduced gelatinolytic activities of proMMP-2 were detected in UT-SCC-43B cell line after 24 and 48 h of incubation with HNP-1 (1 μg/ml: p < 0.001, 5 μg/ml: p < 0.001, and 10 μg/ml: p = 0.0225). MMP-8 levels of both cell lines decreased at 200–250 kDa after 24 h of incubation, while after 48 h only UT-SCC-43B decreased at 45–50 kDa.ConclusionsOur results indicate that HNP-1 suppresses the secretion of MMP-2, -8, and -9 in OSCC cell lines.     

The effect of omega-3 in temporomandibular joint synovial tissues of rats with induced arthritis: pilot study

This study evaluated the effect of systemic administration of omega-3 on the expression of interleukins IL-1β and IL-10 and tumour necrosis factor alpha (TNF-α) and on the thickness of cartilage in the temporomandibular joint (TMJ) inflammatory model induced by complete Freund’s adjuvant (CFA). Thirty-two adult rats were divided equally into four groups: control, CFA (induced arthritis), and induced arthritis animals treated with dexamethasone or omega-3. The TMJs were then removed and assigned to histomorphometric analysis or immunoassay. The Kruskal–Wallis test with Dunn post hoc test was applied to the data; the significance level was set at 5%. IL-1β levels (median; interquartile range) were higher (P < 0.0001) in the CFA group (46.4 ng/ml; 39.4–53.3) than in the control group (1.81 ng/ml; 1.5–5.4), but there were no differences between the control, omega-3, and dexamethasone groups. TNF-α levels were also higher (P < 0.0001) in the CFA group (122.7 ng/ml; 92.9–284.7) than in the control group (29.1 ng/ml; 23.7–31.3). IL-10 levels were lowest (P < 0.0001) in the CFA group (73.5 ng/ml; 52.8–90.5), and no differences were found amongst the other groups. In conclusion, omega-3 successfully reduced the damage in the TMJ of induced arthritis rats. Further investigations are warranted to confirm whether the administration of omega-3 has a comparable effect to glucocorticoids in rheumatoid arthritis patients.     

The efficacy of Salvadora persica extract in the elimination of the intracanal smear layer: A SEM study

AimTo evaluate the efficacy of an ethanolic Salvadora persica extract in removing the smear layer following a root canal procedure.MethodsSixty extracted, single-rooted human teeth were cleaned, shaped, and divided into four groups. Experimental groups 1 (n = 20) and 2 (n = 20) were irrigated with 1 mg/ml and 5 mg/ml of S. persica, respectively. The positive controls (n = 10) were irrigated with 17% ethylenediaminetetraacetic acid (EDTA), while the negative controls (n = 10) were irrigated with saline. Approximately 5 ml of the irrigating solution was delivered into the root canals for 5 min, and the final rinse was performed with 5 ml of 1% sodium hypochlorite. Scanning electron microscopy was used to evaluate the endodontic smear layer removal at the coronal, middle, and apical thirds of the specimens.ResultsA significant difference in smear layer removal between groups 1 and 2 at the coronal and middle thirds of the canal was observed, and no significant difference was seen between group 2 and the positive control at the coronal third. At the apical third, both concentrations of S. persica had similar effects and were less effective than the positive control in removing the smear layer.ConclusionThe 5 mg/ml S. persica solution was significantly more effective than the 1 mg/ml solution. In addition, the 5 mg/ml S. persica solution was as effective as 17% EDTA in removing the smear layer from the coronal third of the canal wall.     

Resveratrol improves bone repair by modulation of bone morphogenetic proteins and osteopontin gene expression in rats

This study investigated the effect of resveratrol on bone healing and its influence on the gene expression of osteogenic markers. Two calvarial defects were created and one screw-shaped titanium implant was inserted in the tibia of rats that were assigned to daily administration of placebo (control group, n = 15) or 10 mg/kg of resveratrol (RESV group, n = 15) for 30 days. The animals were then sacrificed. One of the calvarial defects was processed for histomorphometric analysis and the tissue relative to the other was collected for mRNA quantification of bone morphogenetic protein (BMP)-2, BMP-7, osteopontin (OPN), bone sialoprotein (BSP), osteoprotegrin (OPG), and receptor activator of NF-κB ligand (RANKL). Implants were removed by applying a counter-torque force. Histomorphometric analysis revealed higher remaining defect in the calvarial defects of the control group than the RESV group (P = 0.026). Resveratrol increased the counter-torque values of implant removal when compared to control therapy (P = 0.031). Gene expression analysis showed a higher expression of BMP-2 (P = 0.011), BMP-7 (P = 0.049), and OPN (P = 0.002) genes in the RESV group than in the control group. In conclusion, resveratrol improved the repair of critical-sized bone defects and the biomechanical retention of implants. Indeed, this natural agent may up-regulate the gene expression of important osteogenic markers.     

A study on the protective effect of molecular hydrogen on osteoradionecrosis of the jaw in rats

The aim of this study was to investigate the protective effect of hydrogen in a rat model of osteoradionecrosis of the jaw (ORNJ). The rats and bone marrow-derived mesenchymal stem cells (BMSCs) were pre-treated with hydrogen before receiving irradiation (7 Gy per fraction, five fractions in total once a day for rats, 4 Gy for BMSCs). Reactive oxygen species (ROS) and cell differentiation were measured in the BMSCs. Also, the radioprotective effect of hydrogen for ORNJ in Sprague-Dawley rats was examined by gross clinical manifestations, micro-computed tomography, and histology. Hydrogen significantly reduced the production of ROS in BMSCs after irradiation. The cell viability was significantly decreased after irradiation (P =  0.001), but pre-treatment with hydrogen before irradiation increased the cell viability (P =  0.025). Hydrogen considerably increased the cellular differentiation potential of the irradiated cells. Comparing with the rats underwent irradiaton only, those rats treated by hydrogen-rich saline significantly appeared improved occlusion, salivation, alopecia, oral ulcer, and less bone necrosis. Myofibroblasts accumulated overwhelmingly in the fibrosis medulla and around the sequestrum after irradiation, and this was decreased in the group pre-treated with hydrogen. Hydrogen may represent a strategy for the prevention and treatment of ORNJ. Its high efficacy and low toxicity suggest possible therapeutic application.     

Influence of mandibular residual ridge resorption on objective masticatory measures of lingualized and fully bilateral balanced denture articulation

PurposeTo assess the influence of mandibular residual ridge resorption (RRR) on objective masticatory measures of two occlusal schemes: lingualized occlusion (LO) and fully bilateral balanced articulation (FBBA).MethodsThe enrolled patients (n = 22) were randomly allocated one set of complete dentures with either LO or FBBA. Maximum occlusal force, masticatory performance (by the MPI), and mandibular movements were measured at 3- and 6-month follow-ups. Mandibular RRR was assessed as the sum of the mandibular bone height at the midline, first premolar region, and least vertical height region, and from the mental foramen to the alveolar crest, measured on panoramic radiographs; the treatment groups were subclassified into severe or moderate RRR subgroups by the value of the sum of individual measurements.ResultsSignificant differences were observed in the between-subgroup comparisons (Kruskal–Wallis test) of the MPI (3 months, p = 0.01; 6 months, p = 0.04) and linear deviation from intercuspal position (anterior–posterior: 6 months, p = 0.01; inferior–superior: 3 months, p = 0.008; 6 months, p = 0.02). The patients with severe RRR in the FBBA group showed a significant decrease in the MPI and increase in linear inferior deviation from intercuspal position at 3 months (post hoc comparison) as well as a significant increase in the linear posterior and inferior deviation from intercuspal position at 6 months.ConclusionsLO is the preferable occlusal scheme for patients with severe RRR. (This trial has been registered at http://clinicaltrials.gov/ct2/show/NCT00959530.)     

Treated dentin matrix particles combined with dental follicle cell sheet stimulate periodontal regeneration

ObjectivePeriodontal tissue engineering is an attractive approach for restoring periodontal-supporting structures and functions. However, complete periodontal regeneration has not been accomplished. Previous studies demonstrated the feasibility of using cell sheets and treated dentin matrix (TDM) to regenerate bio-roots.MethodsIn this study, we regenerated periodontal tissue using cell sheets combined with TDM particles (TDMPs). Human dental follicle cells (hDFCs) were isolated and characterized. Human dental follicle cells sheets (hDFCSs) and human TDMPs (hTDMP) were fabricated and characterized. The osteogenic effect of hTDMP was evaluated on human bone marrow stromal cells (hBMSCs) in vitro and a rat calvarial bone defect in vivo. Real-time PCR, western blotting, radiograph analysis, and histological analysis were performed to evaluate the periodontal induction capacity of hTDMP. One-wall periodontal intrabony defects were prepared to evaluate the periodontal regeneration capacity of TDMP/DFCSs on beagle dogs.ResultsThe results showed that hDFCs were mesenchymal stem cells. hTDMP promoted the proliferation and osteogenic differentiation of hBMSCs. New bone formation was observed in the rat calvarial bone defect zone in both the hTDMP and hydroxyapatite/β-tricalcium phosphate groups. Periodontal-like tissues showed better regeneration in the canine TDMP + DFCS group than in the other groups.SignificanceThese results demonstrate the potential of using TDMP/DFCSs in periodontal regeneration.