Molecular events in the jaw vascular unit:A traditional review of the mechanisms involved in inflammatory jaw bone diseases

Inflammatory jaw bone diseases are common in stomatology,including periodontitis,peri-implantitis,medication-related osteonecrosis of the jaw,radiation osteomyelitis of the jaw,age-related osteoporosis,and other specific infections.These diseases may lead to tooth loss and maxillofacial deformities,severely affecting patients'quality of life.Over the years,the reconstruction of jaw bone deficiency caused by inflammatory diseases has emerged as a medical and socioeconomic challenge.Therefore,exploring the pathogenesis of inflammatory diseases associated with jaw bones is crucial for improving prognosis and developing new targeted therapies.Accumulating evidence indicates that the integrated bone formation and dysfunction arise from complex interactions among a network of multiple cell types,including osteoblast-associated cells,immune cells,blood vessels,and lymphatic vessels.However,the role of these different cells in the inflammatory process and the'rules'with which they interact are still not fully understood.Although many investigations have focused on specific pathological processes and molecular events in inflammatory jaw diseases,few articles offer a perspective of integration.Here,we review the changes and mechanisms of various cell types in inflammatory jaw diseases,with the hope of providing insights to drive future research in this field.

Comparison of Maxillary Implant-Supported Prostpesis in Irradiated and Non-Irradiated Patients

In order to investigate the influence of radiation therapy after the treatment of maxillary implant-supported prostheses, 27 patients received a total of 131 implants in maxilla after oral cancer treatment and/or reconstructive surgery. Among them, 25 received maxillary implant-supported prostheses. The cumulative survival rates of implants and prostheses were evaluated by the product-limit-estimates method according to Kaplan-Meier. The cumulative survival rate of implants and prostheses in irradiated patients was compared with that in non-irradiated patients by statistical Log-rank test. The results showed that 112 implants were observed after implant loading. The implants cumulative survival rate was approximately 65 % for overall patients. The cumulative prosthesis successful rate was approximately 88 % for all 25 patients. Log-rank test analysis revealed that there was a significant difference in cumulative implants survival rates between non-irradiated and irradiated maxillary bone (P<0. 01). It was concluded that the implants and prostheses in irradiated patients have significantly lower survival rates than in non-irradiated patients.

Effect of Bone Marrow Mesenchymal Stem Cells Transfected with rAAV2-bFGF on Early Angiogenesis of Calvarial Defects in Rats

The purpose of this study was to evaluate the effect of bone marrow mesenchymal stem cells (MSCs) transfected with the basic fibroblast growth factor (bFGF)-expressing recombinant adeno-associated virus vector (rAAV2-bFGF), on early angiogenesis of calvarial defects in rats. The MSCs were cultured and transfected with rAAV2-bFGF after differential adherence isolation. The transfection efficiency was detected by RT-PCR and Western blotting. The transfected MSCs were compounded with poly-DL-lactide/hydroxyapatite (PDLLA/HA) in vitro. The cranial defect models in 36 male SD rats were created. Nothing (group A), PDLLA/HA alone (group B), PDLLA/HA combined with MSCs (group C), and PDLLA/HA combined with rAAV2-bFGF transfected MSCs (group D) were implanted in rat calvarial defects. The specimens were harvested for hematoxylin-eosin staining on the day 1, 3 and 7 after implantation. Factor Ⅷ immunohistochemical staining and histomorphometric analysis were carried out to evaluate neovascularization around the implantation. The results indicated that MSCs could indeed be successfully transfected with the rAAV2-bFGF vector. Histological and histomorphometric analysis revealed that the angiogenesis in group D was significantly enhanced as compared with the rest groups (P<0.05). These results strongly suggest that MSCs transfected with rAAV2-bFGF in combination with PDLLA/HA can effectively promote the early angiogenesis of calvarial defects in rats, which played an important role in creating an environment suitable for the survival and activity of transplanted cells for further applications in cranio-maxillofacial bone regeneration.

Effect of Saliva Contamination on Shear Bond Strength of Orthodontic Brackets When Using a Self-Etch Primer

The effect of saliva contamination on the shear bond strength of orthodontic brackets, at various stages of the bonding procedure using a new self-etch primer was studied. The samples were divided into 4 groups according to 4 different enamel surface conditions: Group A: dry; Group B: saliva contamination before priming; Group C: saliva contamination after priming, and Group D: saliva contamination before and after priming. Stainless steel brackets were bonded in each test group with a light-cured composite resin (TransbondXT 3M). The shear bond strength was determined in the first 30 min after bonding. The analysis of variance indicated that the shear bond strengths of the 4 groups were significantly different (F=11.89, P<0.05). Tukey HSD tests indicated that contamination both before and after the application of the acid-etch primer resulted in a significantly lower (=4.6±1.7 MPa) shear bond strength than either the control group (=8.8±1.9 MPa) or the groups where contamination occurred either before (=7.9±2.0 MPa) or after (=6.9±1.5 MPa) the application of the primer. It was concluded that the new acid-etch primer could maintain adequate shear bond strength if contamination occurred either before or after the application of the primer. On the other hand, contamination both before and after the application of the primer could significantly reduce the shear bond strength of orthodontic brackets.

An in vitro Investigation into Retention Strength and Fatigue Resistance of Various Designs of Tooth/Implant Supported Overdentures

Previously, the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected. Little or no data have been available on the correlation between the attachment system selected and the overdenture support configuration. The purpose of the present study was to evaluate the retention force and fatigue resistance of three attachment systems and four support designs of overdenture prosthesis. Four lower edentulous acrylic models were prepared and eight combinations of attachments groups were investigated in the study. These included: O-Rings with mini-dental implants (MDIs), Dalbo elliptic with Dalbo Rotex and fabricated flexible acrylic attachments with both MDI and Dalbo Rotex. The study was divided into four test groups: groups A and B, controls, and groups C and D, experimental groups. Control group A contained three overdenture supports: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with Dalbo Rotex screwed in. Control group B contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with Dalbo Rotex screwed in at the same MDI position, but on the left side of the model. Experimental group C contained three overdenture support foundations: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with MDI screwed in. Experimental group D contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with MDIs screwed in at the same MDI position, but on the left side of the model. Each group was further divided into two subgroups according to attachment type used. Five samples were prepared for each group. Retention force (N) values were recorded initially (0 cycles) and after 360, 720, 1440 and 2880 insertion and removal cycles. During the tensile test a cross-head speed of 10 mm/min was applied. Values of absolute force (AF) and relative force (RF) were statistically analyzed by two-way ANOVA and multiple comparison Tukey’s tests between groups and cycles periods. The results of fatigue tests showed a 50% reduction in retention force in the subgroups with flexible attachments. A triangular design of overdenture support foundations with O-Ring attachments revealed the lowest value of AF and a relatively high reduction in RF. The four overdenture support designs with flexible acrylic attachments improved the retention force and reduced the fatigue retention. Furthermore, the results of the investigation demonstrate that flexible acrylic attachments for both teeth and implant-supported overdentures offer a wide range of retention forces.

Construction of Adeno-associated Virus System for Human Bone Morphogenetic Protein 7 Gene

To construct the recombinant adeno-associated virus （rAAV） vector with human bone morphogenetic protein 7 （BMP7） and observe the BMP7 mRNA expression in vitro, BMP7 CDS sequence was cloned into expression plasmid pAAV-MCS of AAV Helper Free System. The recombinant plasmid was identified with enzyme digestion and sequencing. The recombinant plasmid, pAAV-RC, pHelper were co-transfected into AAV-293 cells according to the calcium phosphate-based protocol. The viral stock was collected by 4 rounds of freeze/thaw. After purified and concentrated, the recombinant virus titer was determined by dot-blot assay. HEK293 cells were transfected with the recombinant virus at different MOI, and the expression of BMP7 mRNA was detected by RT-PCR. The results showed rAAV-BMP7 was constructed and packaged successfully. The physical particle titer was 2.5×10^11 vector genomes/mL. There was different expression level of BMP7 mRNA after transfecton. These data suggested that recombinant AAV mediated a stable expression of hBMP7 mRNA in 293 cells. The AAV production method may pave the way of an effective strategy for the jaw bone defection around dental implants.

Oral pathogen aggravates atherosclerosis by inducing smooth muscle cell apoptosis and repressing macrophage efferocytosis

Periodontitis imparting the increased risk of atherosclerotic cardiovascular diseases is partially due to the immune subversion of the oral pathogen,particularly the Porphyromonas gingivalis(P.gingivalis),by inducing apoptosis.However,it remains obscure whether accumulated apoptotic cells in P.gingivalis-accelerated plaque formation are associated with impaired macrophage clearance.

Sol-gel derived B_(2)O_(3)-CaO borate bioactive glasses with hemostatic,antibacterial and pro-angiogenic activities

Sol-gel borate bioactive glasses(BGs)are promising ion-releasing biomaterials for wound healing applications.Here,we report the synthesis of a series of binary B_(2)O_(3)-CaO borate BGs(CaO ranging from 50 to 90mol%)using a sol-gel-based method.The influence of CaO content in B_(2)O_(3)-CaO borate BG on morphology,structure and ion release behavior was investigated in detail.Reduced dissolution(ion release)and crystallization could be observed in borate BGs when CaO content increased,while the morphology was not significantly altered by increasing CaO content.Our results evidenced that the ion release behavior of borate BGs could be tailored by tuning the B_(2)O_(3)/CaO molar ratio.We also evaluated the in vitro cytotoxicity,hemostatic,antibacterial and angiogenic activities of borate BGs.Cytocompatibility was validated for all borate BGs.However,borate BGs exhibited composition-dependent hemostatic,antibacterial and angiogenic activities.Generally,higher contents of Ca in borate BGs facilitated hemostatic activity,while higher contents of B_(2)O_(3) were beneficial for pro-angiogenic activity.The synthesized sol-gel-derived borate BGs are promising materials for developing advanced wound healing dressings,given their fast ion release behavior and favorable hemostatic,antibacterial and angiogenic activities.

Surface demineralized freeze-dried bone allograft followed by reimplantation in a failed mandibular dental implant

The removal of a failed implant with high torque causes significant damage to the surrounding tissue,compromising bone regeneration and subsequent osseointegration in the defect area.Here,we report a case of carrier screw fracture followed by immediate implant removal,bone grafting and delayed reimplantation.A dental implant with a fractured central carrier screw was removed using the bur-forceps technique.The resulting three-wall bone defect was filled with granular surface demineralized freeze-dried bone allograft(SD-FDBA).Cone-beam computerized tomography was performed at 1week,6months and 15months postoperatively and standardized for quantitative evaluation.The alveolar bone width and height at 15months post-surgery were about 91%of the original values,with a slightly lower bone density,calculated using the gray value ratio.The graft site was reopened and was found to be completely healed with dense and vascularized bone along with some residual bone graft.Reimplantation followed by restoration was performed 8months later.The quality of regenerated bone following SD-FDBA grafting was adequate for osseointegration and longterm implant success.The excellent osteogenic properties of SD-FDBA are attributed to its human origin,cortical bone-like structure,partly demineralized surfaces and bone morphogenetic protein-2-containing nature.Further investigation with more cases and longer follow-up was required to confirm the final clinical effect.

Bioactive materials from berberine-treated human bone marrow mesenchymal stem cells promote alveolar bone regeneration by regulating macrophage polarization

Alveolar bone regeneration has been strongly linked to macrophage polarization.M1 macrophages aggravate alveolar bone loss,whereas M2 macrophages reverse this process.Berberine(BBR),a natural alkaloid isolated and refined from Chinese medicinal plants,has shown therapeutic effects in treating metabolic disorders.In this study,we first discovered that culture supernatant(CS)collected from BBR-treated human bone marrow mesenchymal stem cells(HBMSCs)ameliorated periodontal alveolar bone loss.CS from the BBR-treated HBMSCs contained bioactive materials that suppressed the M1 polarization and induced the M2 polarization of macrophages in vivo and in vitro.To clarify the underlying mechanism,the bioactive materials were applied to different animal models.We discovered macrophage colony-stimulating factor(M-CSF),which regulates macrophage polarization and promotes bone formation,a key macromolecule in the CS.Injection of pure M-CSF attenuated experimental periodontal alveolar bone loss in rats.Colony-stimulating factor 1 receptor(CSF1R)inhibitor or anti-human M-CSF(M-CSF neutralizing antibody,Nab)abolished the therapeutic effects of the CS of BBR-treated HBMSCs.Moreover,AKT phosphorylation in macrophages was activated by the CS,and the AKT activator reversed the negative effect of the CSF1R inhibitor or Nab.These results suggest that the CS of BBR-treated HBMSCs modulates macrophage polarization via the M-CSF/AKT axis.Further studies also showed that CS of BBR-treated HBMSCs accelerated bone formation and M2 polarization in rat teeth extraction sockets.Overall,our findings established an essential role of BBR-treated HBMSCs CS and this might be the first report to show that the products of BBR-treated HBMSCs have active effects on alveolar bone regeneration.

Cerium oxide nanoparticles loaded nanofibrous membranes promote bone regeneration for periodontal tissue engineering

Bone regeneration is a crucial part in the treatment of periodontal tissue regeneration,in which new attempts come out along with the development of nanomaterials.Herein,the effect of cerium oxide nanoparticles(CeO_(2)NPs)on the cell behavior and function of human periodontal ligament stem cells(hPDLSCs)was investigated.Results of CCK-8 and cell cycle tests demonstrated that CeO_(2)NPs not only had good biocompatibility,but also promoted cell proliferation.Furthermore,the levels of alkaline phosphatase activity,mineralized nodule formation and expressions of osteogenic genes and proteins demonstrated CeO_(2)NPs could promote osteogenesis differentiation of hPDLSCs.Then we chose electrospinning to fabricate fibrous membranes containing CeO_(2)NPs.We showed that the composite membranes improved mechanical properties as well as realized release of CeO_(2)NPs.We then applied the composite membranes to in vivo study in rat cranial defect models.Micro-CT and histopathological evaluations revealed that nanofibrous membranes with CeO_(2)NPs further accelerated new bone formation.Those exciting results demonstrated that CeO_(2)NPs and porous membrane contributed to osteogenic ability,and CeO_(2)NPs contained electrospun membrane may be a promising candidate material for periodontal bone regeneration.

Treatment of gingival hyperplasia induced by cyclosporine A

The clinical therapy for cyclosporine A(CsA)-induced gingival hyperplasia(GH)and the pathological changes in hyperplastic gingival tissues were investigated.Nine cases of CsA-induced GH after renal transplantation were subjected to periodontal non-surgical treatment and surgical treatment and were followed up.Gingival index(GI),dental plaque index(PLI)and GH degree(GHD)at different time points were measured.Under light and elec-tron microscopy,the pathological changes in hyperplastic gingival tissues were observed.The CsA concentrations in gingival tissues and blood were determined by using fluor-escence polarization immunoassay with TDxFLx monoclo-nal antibody.The results showed that GI,PLI and GHD in patients with GH declined after periodontal treatment.Two patients suffered from different degrees of GH during the 6 months to 54 months post-transplantation.Under trans-mission electron microscopy,fibroblasts in the hyperplastic gingival tissues were enlarged,cytoplasmic rough endoplas-mic reticula were abundant and expanded slightly,and a few fibroblasts with early apoptotic changes were seen.The concentrations of CsA in hyperplastic gingival tissues were from 351.00 to 1345.47 ng/mL,which were significantly higher than in the blood of the same patients taken at the same time points.It was concluded that GI and PLI declined after periodontal treatment in combination with surgical treatment in patients taking CsA for a long time,but in some patients,GH recurred.The fact that the con-centration of CsA in hyperplastic gingival tissues is higher than in blood awaits further studies.

Biomineralization inspired 3D printed bioactive glass nanocomposite scaffolds orchestrate diabetic bone regeneration by remodeling micromilieu

TypeⅡdiabetes mellitus(TIIDM)remains a challenging clinical issue for both dentists and orthopedists.By virtue of persistent hyperglycemia and altered host metabolism,the pathologic diabetic micromilieu with chronic inflammation,advanced glycation end products accumulation,and attenuated biomineralization severely impairs bone regeneration efficiency.Aiming to“remodel”the pathologic diabetic micromilieu,we 3D-printed bioscaffolds composed of Sr-containing mesoporous bioactive glass nanoparticles(Sr-MBGNs)and gelatin methacrylate(GelMA).Sr-MBGNs act as a biomineralization precursor embedded in the GelMA-simulated extracellular matrix and release Sr,Ca,and Si ions enhancing osteogenic,angiogenic,and immunomodulatory properties.In addition to angiogenic and anti-inflammatory outcomes,this innovative design reveals that the nanocomposites can modulate extracellular matrix reconstruction and simulate biomineralization by activating lysyl oxidase to form healthy enzymatic crosslinked collagen,promoting cell focal adhesion,modulating osteoblast differentiation,and boosting the release of OCN,the noncollagenous proteins(intrafibrillar mineralization dependent),and thus orchestrating osteogenesis through the Kindlin-2/PTH1R/OCN axis.This 3D-printed bioscaffold provides a multifunctional biomineralization-inspired system that remodels the“barren”diabetic microenvironment and sheds light on the new bone regeneration approaches for TIIDM.

Regulating macrophage-MSC interaction to optimize BMP-2-induced osteogenesis in the local microenvironment

Bone morphogenetic protein(BMP-2)has been approved by the FDA to promote bone regeneration,but uncertain osteogenic effect and dose-dependent side effects may occur.Osteoimmunomodulation plays an important role in growth factor-based osteogenesis.Here,we explored how proinflammatory signals affect the dose-dependent osteogenic potential of BMP-2.We observed that the expression level of local IL-1βdid not increase with the dose of BMP-2 in the mouse osteogenesis model.A low dose of BMP-2 could not promote new bone formation,but trigger the release of IL-1βfrom M1 macrophages.As the dose of BMP-2 increased,the IL-1βexpression and M1 infiltration in local microenvironment were inhibited by IL-1Ra from MSCs under osteogenic differentiation induced by BMP-2,and new bone tissues formed,even excessively.Anti-inflammatory drugs(Dexamethasone,Dex)promoted osteogenesis via inhibiting M1 polarization and enhancing BMP-2-induced MSC osteo-differentiation.Thus,we suggest that the osteogenic effect of BMP-2 involves macrophage-MSC interaction that is dependent on BMP-2 dose and based on IL-1R1 ligands,including IL-1βand IL-1Ra.The dose of BMP-2 could be reduced by introducing immunoregulatory strategies.