Surface-modified titanium and titanium-based alloys for improved osteogenesis: A critical review.

As implantable materials, titanium, and its alloys have garnered enormous interest from researchers for dental and orthopedic procedures. Despite their success in wide clinical applications, titanium, and its alloys fail to stimulate osteogenesis, resulting in poor bonding strength with surrounding bone tissue. Optimizing the surface topology and altered compositions of titanium and titanium-based alloys substantially promotes peri-implant bone regeneration. This review summarizes the utilization and importance of various osteogenesis components loaded onto titanium and its alloys. Further, different surface-modification methods and the release efficacy of loaded substances are emphasized. Finally, we summarize the article with prospects. We believe that further investigation studies must focus on identifying novel loading components, exploring various innovative, optimized surface-modification methods, and developing a sustained-release system on implant surfaces to improve peri-implant bone formation.

Tuning osteoporotic macrophage responses to favour regeneration by Cu-bearing titanium alloy in Porphyromonas gingivalis lipopolysaccharide-induced microenvironments.

Guided bone regeneration in inflammatory microenvironments of osteoporotic patients with large alveolar bone defects remains a great challenge. Macrophages are necessary for alveolar bone regeneration via their polarization and paracrine actions. Our previous studies showed that Cu-bearing Ti6Al4V alloys are capable of regulating macrophage responses. When considering the complexity of oral microenvironments, the influences of Cu-bearing Ti6Al4V alloys on osteoporotic macrophages in infectious microenvironments are worthy of further investigations. In this study, we fabricated Ti6Al4V-Cu alloy by selective laser melting technology and used Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) to imitate oral pathogenic bacterial infections. Then, we evaluated the impacts of Ti6Al4V-Cu on osteoporotic macrophages in infectious microenvironments. Our results indicated that Ti6Al4V-Cu not only inhibited the P.g-LPS-induced M1 polarization and pro-inflammatory cytokine production of osteoporotic macrophages but also shifted polarization towards the pro-regenerative M2 phenotype and remarkably promoted anti-inflammatory cytokine release. In addition, Ti6Al4V-Cu effectively promoted the activity of COMMD1 to potentially repress NF-κB-mediated transcription. It is concluded that the Cu-bearing Ti6Al4V alloy results in ameliorated osteoporotic macrophage responses to create a favourable microenvironment under infectious conditions, which holds promise to develop a GBR-barrier membrane for alveolar bone regeneration of osteoporosis patients.

[Effect of hBMP-7 gene modified bone marrow stromal cells on periodontal tissue regeneration].

OBJECTIVE: To estimate the potential effects of hBMP-7 gene transfected bone marrow stromal cells (BMSC) and to provide a new way for repairing the periodontal defects. METHODS: A total of 30 experimental class II furcation defects in five Beagle dogs were created surgically. The transfected and non-transfected BMSC were seeded in collagen membrane at an initial concentration of 1 x 10(7)/ml and transplanted into experimental class II furcation defects. The animals were sacrificed at 12 weeks post-operation and periodontal regeneration was evaluated by the histological and morphometric analysis. RESULTS: In both experimental and control groups, there were different extents of regeneration. The percentage of new alveolar area in transfected and non-transfected BMSC were significantly higher than the control (P < 0.05). And there was also significant difference between two experimental groups (P < 0.05). The percentage of new cementum length in two experimental groups were significantly higher than the control (P < 0.05). But there was no significant difference between two BMSCs groups (P > 0.05). CONCLUSION: hBMP-7 gene enhanced tissue engineering could be a better way to repair the periodontal defects.

Preparation of biocompatible nano-ZnO/chitosan microspheres with multi-functions of antibacterial, UV-shielding and dye photodegradation.

Nano-ZnO (nZnO) has been widely used as antibacterial, UV-shielding and photocatalysis materials, but limited by its contentious biosafety. In this paper, chitosan (CS) was introduced to enhance the biocompatibility. To solve the problem that nZnO reacts with the CS acid solution, alternate-feed spray drying was adopted to fabricate nZnO/CS composite microspheres. It was showed that nZnO remained the hexagonal phase, dispersed and embedded into CS microspheres. Based on the results of cytotoxicity and hemolysis test, biosafety was improved obviously. Further, the antibacterial activity of nZnO/CS was notably better than either of CS and nZnO individually. UV-shielding property and photocatalytic degradation test were estimated. In a word, alternate-feed spray drying presents a novel and cost-efficient method to fabricate multifunctional nZnO/CS microspheres with enhanced biosafety.

Dual drug loaded coaxial electrospun PLGA/PVP fiber for guided tissue regeneration under control of infection.

Electrospinning promisingly fabricate mats for Guided Tissue Regeneration (GTR). Due to a chronic inflammatory pathology in periodontal, it is highly desirable to develop a novel GTR mats to realize tissue regeneration under control of infection. In the study, coaxial electrospinning was firstly conducted to fabricate dual drug loaded fiber mats with core/shell structure. Naringin-loaded polyvinylpyrrolidone was designed as core fiber to enrich tissue regeneration and metronidazole-loaded poly(lactic-co-glycolic acid) as shell fiber to inhibit bacterial. TEM revealed that the fibers with distinct core/shell structure were in an outer diameter of 1.5-1.7 µm with an inner diameter of <1.0 µm. The loading of dual drug decreased the tensile strength and elongation of the coaxial fiber mats. On in vitro assessment, metronidazole had a short-term release while naringin had a long-term release behavior in all the coaxial mats. The colonization of anaerobic bacteria on the mats effectively were inhibited over 21 days. Furthermore, the dual drug loaded coaxial fiber mats were observed to positively supported the adhesion and proliferation of MC3T3-E1 and was conductive to high alkaline phosphatase express. Thus, a simple and effective coaxial electrospinning approach was demonstrated for the fabrication of anti-infective GTR mats with promoting tissue regeneration.

[Transient expression of exogenous human platelet-derived growth factor-B in gingival fibroblasts of dog].

OBJECTIVE: To explore transient expression of the eukaryotic expression plasmid carrying human platelet-derived growth factor-B (hPDGF-B) in gingival fibroblasts of Beagle dog. METHODS: Plasmid carrying hPDGF-B (EX-A0380-M03) was amplified and identified, and then transfected into gingival fibroblasts of Beagle dog. Reverse transcription polymerase chain reaction (RT-PCR), immunocytochemistry, enzyme-linked immunosorbent assay (ELISA) and Western bolt were choose to detect the expression of hPDGF-B. RESULTS: Target gene carried by EX-A0380-M03 was hPDGF-B. Green fluorescence protein (GFP) expressed by transfected gingival fibroblasts was observed under inverted phase contrast fluorescence microscope (IPCFM) (after 24 hours) and the transfection efficiency was 18%-38% (after 48 hours). Serials other methods (RT-PCR, immunocytochemistry, and ELISA) mentioned above also convinced that cells expressed hPDGF-B, and the protein that was a kind of fusion protein composed of PDGF-BB and GFP was identified by Western blot. CONCLUSION: Eukaryotic expression plasmid carrying hPDGF-B was transfected into gingival fibroblasts successfully, and a kind of fusion protein was expressed.

[A cross-sectional study on periodontal conditions in elderly people in Wuxi city].

PURPOSE: The present study was aimed to investigate the periodontal conditions in elderly people in Wuxi city, and to provide information for prevention of periodontal disease. METHODS: In a cross-sectional study, 1156 subjects (aged from 65 to 74 years old) were examined. Oral hygiene index-simplified(OHI-S), gingival index(GI), bleeding on probing(BOP), pocket depth (PD) and clinical attachment level(CAL)were measured to evaluate the periodontal condition. The data were analyzed with SPSS12.0 software package for Student's t test and Chi-square test. RESULTS: The oral hygiene index-simplified of elder people in Wuxi City was 3.16±1.48, the gingival index was 1.33±0.54. Among BOP, PD and AL, no significant difference was found between rural and urban district in Wuxi city. CONCLUSIONS: These results suggests that periodontal disease is quite common, poor periodontal conditions were found in elderly people in Wuxi city, great efforts are needed to prevent periodontal disease, and strengthen oral hygiene instruction. Supported by Science and Technology Project of Wuxi City (Grant No.csz00802).