A digital technique for a prefabricated custom post-and-core restoration.

This technique provides a prefabricated and custom post-and-core to restore endodontically treated teeth to be delivered at the preparation appointment. Cone beam computed tomography (CBCT) is used to extract the post shape from a root canal, and a computer-aided design and computer-aided manufacturing (CAD-CAM) software program is used to design the core. The post and the core are combined and milled before post space preparation. Three-dimensional preparation guides are fabricated and used in post space preparation to ensure that the prefabricated and custom post-and-core fits after the preparation. This technique can save time and reduce the risk of perforation while preparing the root canal.

In-vitro characterization and evaluation of mesoporous titanium dioxide composite hydroxyapatite and its effectiveness in occluding dentine tubules.

BACKGROUND: To synthesize mesoporous titanium dioxide composite hydroxyapatite (TiO2-HAP) and to evaluate its effectiveness in sealing of occluding dentine tubules. METHODS: TiO2-HAP was synthesized by chemical precipitation method and characterized using infrared absorption spectrometer, X-ray diffraction, scanning electron microscope, and specific surface area detector. Forty completely extracted molars were prepared and randomly assigned into Control group, Gluma group, HAP group and TiO2-HAP group according to different treatments. The characteristics of HAP and TiO2-HAP and the sealing effectiveness of dentine tubules in these four groups, including infrared spectrum, surface contact angle, pore size distribution, and re-mineralized enamel surface profiles, were analyzed by suitable characterized techniques. The cytotoxicity of the synthesized TiO2-HAP was tested and compared using 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) colorimetry. RESULTS: Our results showed TiO2-HAP group had significantly lower contact angle, higher specific surface area, and wider range of pore size distribution than other groups. The majority of dentinal tubules in the TiO2-HAP group were blocked by white matter in a uniformed manner, and the crystals arranged in order grew along the axial direction. In addition, no significant difference in optical density (OD) value was found between control group and TiO2-HAP group (P > 0.05), and cell growth was good in TiO2-HAP group, indicating no cytotoxicity of TiO2-HAP. CONCLUSIONS: The MTT assay identified that TiO2-HAP had little effect on the L929 cell line. We showed TiO2-HAP might be used as a remineralization agent in enamel caries-like lesions.

microRNA-143-3p regulates odontogenic differentiation of human dental pulp stem cells through regulation of the osteoprotegerin-RANK ligand pathway by targeting RANK.

NEW FINDINGS: What is the central question of this study? What is the role of miR-143-3p during human dental pulp stem cell (hDPSC) differentiation. What is the main finding and its importance? miR-143-3p negatively regulates receptor activator of nuclear factor-κB (RANK). RANK ligand (RANKL) binds to RANK and stimulates the development of osteoclasts. Osteoprotegerin (OPG) inhibits the interaction between RANK and RANKL. The OPG-RANKL signalling pathway regulates odontogenic differentiation of hDPSCs. ABSTRACT: Human dental pulp stem cells (hDPSCs) are capable of differentiating into odontoblast-like cells, which secrete reparative dentin after injury, in which the role of microRNA-143-3p (miR-143-3p) has been identified. Therefore, we investigated the mechanism by which miR-143-3p influences odontoblastic differentiation of hDPSCs. The relationship between miR-143-3p and receptor activator of nuclear factor-κB (RANK) was initially identified by bioinformatics prediction and further verified by dual luciferase reporter gene assay. Gain- and loss-of-function analysis with miR-143-3p mimic and miR-143-3p inhibitor was subsequently conducted. Dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP), alkaline phosphatase (ALP), osteocalcin (OCN) and osteopontin (OPN) mRNA levels were then evaluated by RT-qPCR. Osteoprotegerin (OPG), RANK ligand (RANKL), nuclear factor-κB (NF-κB) p65 protein levels and the extent of NF-κB p65 phosphorylation were examined by western blot analysis. Alizarin red staining was performed to assess the mineralization of hDPSCs. Cell apoptosis and cell cycle distribution were determined using flow cytometry. During odontoblastic differentiation of hDPSC, miR-143-3p had high expression, but RANK expression was low. miR-143-3p was found to target RANK, and its inhibition enhanced mineralization and hDPSC apoptosis, while blocking cell cycle entry. At the same time, miR-143-3p inhibition elevated the extent of NF-κB p65 phosphorylation, as well as the expression of RANK, RANKL, DSPP, BSP, ALP, OCN and OPN, while decreasing the OPG level. Silencing RANK had opposite effects on these markers. miR-143-3p regulates odontoblastic differentiation of hDPSCs via the OPG-RANKL pathway that targets RANK. The elucidation of the mechanisms of odontogenic differentiation of hDPSCs may contribute to the development of effective dental pulp repair therapies for the clinical setting.

RISK OF SILICONE OIL AS VITREOUS TAMPONADE IN PARS PLANA VITRECTOMY: A Systematic Review and Meta-Analysis.

PURPOSE: The authors examined the differences between silicone oil and other vitreous tamponades or placebo in performing pars plana vitrectomy. METHODS: This review and meta-analysis was conducted in accordance with the PRISMA guidelines. Seven databases and the reference lists of the retrieved randomized controlled trial articles were searched to identify eligible studies. The primary outcomes were the rate of redetachment after endotamponade removal, the rate of reoperation, and poor visual acuity. The secondary outcomes were adverse events and quality of life related to postoperative position. RESULTS: Ten articles (12 trials) were included. There were no significant differences between silicone oil and other agents in most of the primary and second outcomes. Only the risk of hypotony was found to be significantly lower when filling with silicone oil, compared with other agents. No trial reported the quality of life related to postoperative position. CONCLUSION: Based on the available studies, the authors conclude that there is no significant difference in the risk of poor outcomes between pars plana vitrectomy with silicone oil and that with other vitreous tamponades with different surgical histories.

Differences in facial profile and dental esthetic perceptions between young adults and orthodontists.

INTRODUCTION: The principal aim of this study was to investigate differences in perception of soft-tissue facial profiles and dental esthetics between young Chinese adults and orthodontists. METHODS: Eight hundred ninety-two subjects (444 male, 448 female), ages 16 to 24 years, chose 1 image from among 5 profile silhouettes and from among 10 ranked color photographs of the aesthetic component (AC) of the index of orthodontic treatment need that most closely resembled their own profile and dental esthetic appearance, respectively. A panel of 20 orthodontists then independently repeated the same image selection process. Each subject also completed the Eysenck personality questionnaire for psychoticism. We used the Mann-Whitney U test and the Spearman rank correlation test, with statistical significance set at α = 0.05. RESULTS: Only 37.0% of subjects had straight profiles by objective orthodontic assessment, but 85.0% chose straight profiles by subjective self-perception. About 17.5%, mainly females, chose the mild convex as the ideal profile. Only 2.5% of the subjects were ranked 1 on the AC by orthodontists, but 43.6% chose 1, or ideal, by self-perception. Male subjects scored significantly higher than did female subjects for self-perceived facial profiles (more protruded chins) and for the AC (more attractive dental appearance). Subjects with high psychoticism T scores (>50) scored significantly lower for self-perceived facial profiles (more retruded chins) and on the AC (less attractive dental appearance). CONCLUSIONS: Young Chinese adults perceived their facial profiles and dental appearances to be significantly more straight and attractive, respectively, than did the orthodontists. A significant proportion of the young adults, mainly women, preferred a mild convex facial profile. High psychoticism scores might significantly affect the self-perception of orthodontic treatment needs.

Removal of fiber post under the guidance of digital guide plate and one-piece glass fiber posts-and-cores repair: a clinical report.

This study explores the potential application of computer aided design (CAD)/computer aided manufac-turing (CAM) for one-piece glass fiber posts and cores in restoring tooth defects post-removal of a broken fiber post using a digital guide plate. This paper reports a fractured left upper incisor fiber post removed using a customized needle and digital guide plate. Following root canal retreatment, CAD/CAM integrated fiber post-core and zirconia full crown restoration were completed. The occlusion testing was conducted using the T-Scan Ⅲ system. This study offers insights for managing secondary repair after fiber post fractures.

The removal of three kinds of occlusal veneers by Er: Yag laser.

OBJECTIVES: This study aimed to remove occlusal veneers of varied thicknesses and compositions by Er:Yag laser in vitro and analyze the interfacial microstructure between veneers and tooth that irradiated by laser, by which experimental evidence could be provided to support the non-invasive removal of occlusal veneerby laser. METHODS: Fresh mandibular premolars extracted for orthodontic requirements were collected for tooth preparation. Three kinds of ceramic materials (Vita Suprinity, Vita Mark Ⅱ, and Upcera Hyramic) were selected to fabricate occlusal veneer with different thicknesses (1.0, 1.5, and 2.0 mm). One week later, Er:Yag laser (2.5 W and 3.5 W) was used to irradiate and remove the occlusal veneer and recorded the timespan. After the removal operation, the micro-morphologies of samples were examined by scanning electron microscope. RESULTS: Upcera Hyramic veneer failed to be removed (>20 min); the operation span at 2.5 W, Vita Suprinity (96.0 s±16.0 s) was longer than Vita MarkⅡ(84.5 s±19.5 s) in the 1.0 mm group (P<0.05), and Vita Suprinity (246.5 s±13.5 s) was longer than Vita MarkⅡ(170.0 s±14.0 s) in the 1.5 mm group (P<0.05). At 3.5 W, Vita Suprinity (381.0 s±24.0 s) was longer than Vita MarkⅡ(341.5 s±26.5 s) in the 2.0 mm group. CONCLUSIONS: Increasing laser power could shorten the operation span and facilitate the removal of occlusal veneers with the same thickness and composition. The occlusal veneer was sustained when insufficient laser power was applied. With the same laser power and ceramic thickness, laser penetration could interfere with the integral of the ceramic structure when the laser interacted with the bonding layer. With the same ceramic composition and laser power, the operation span and laser power increased with the thickness of the occlusal veneer. However, the laser was incapable of removing occlusal resin veneer directly.

Removal of broken screws on implant abutment by digital guide plate: A case report and literature review.

Implant restoration is currently the most mainstream method for repairing missing teeth. With the increasing number of plantings, various planting complications begin to be paid attention to. Among them, there are many reports of disability phenomena such as loose and broken abutment screws and broken top screws, which cause the implant to fail or fail to function. In recent years, with the development of computer-aided software and its application in the field of oral treatment, digital guide plates based on 3D printing of oral CBCT scanning data are widely used in oral implants. Therefore, we explore the application prospect of post-core crown restoration after removing broken screws from the implant abutment with a digital guide plate. We reported a case of upper right first molar implant abutment screws broken, which were removed by a digital guide plate and customized turning bur. The resin-matrix ceramics crown post core was prepared, and then the occlusal force was tested by the T-ScanIII system. It provides a reference for the application of digital guide plates in special cases such as broken screws of implant abutment.

Apical root resorption in maxillary incisors when employing micro-implant and J-hook headgear anchorage: a 4-month radiographic study.

This study evaluated, over a 4-month study period, the amount of apical root resorption occurring in maxillary central incisors following their retraction when employing either micro-implant or J-hook headgear anchorage. The prospective randomised clinical trial was conducted in Orthodontic Clinic, College of Stomatology, China from 2008-2009. Subjects are patients requiring fixed appliances on waiting list (n=20). In female Han Chinese patients aged from 16-26 years, standardized periapical radiographs from 10 randomly assigned patients with maxillary protrusions comprising the micro-implant group, and from 10 similar patients comprising the J-hook headgear group, were assessed for maxillary central incisor apical root resorption. Measurements before and after orthodontic therapy were also obtained from lateral cephalometric radiographs to calculate incisor horizontal retraction and vertical intrusion distances. Estimated retraction force vectors were calculated in horizontal and vertical directions for both treatment groups. Data analysis employed t-tests and the Pearson correlation test, with α=0.05 for statistical significance. The results showed that when compared with the J-hook group, significantly more apical root resorption shortening of the maxillary central incisors was observed in the micro-implant group (1.27 mm difference, 95% CI=0.70-1.84, P<0.001), which was associated with a significantly larger retraction distance (P=0.004) and a smaller vertical force component (P<0.0001). We are led to conclude that continuous activation of the nickel-titanium coil springs used in the micro-implant group resulted in significantly more apical root resorption shortening and maxillary central incisor retraction than when intermittent J-hook retraction was employed. The employment of continuous duration orthodontic forces presents a risk for increased apical root resorption that requires careful radiographic monitoring.

Overexpression of long noncoding RNA MCM3AP-AS1 promotes osteogenic differentiation of dental pulp stem cells via miR-143-3p/IGFBP5 axis.

MCM3AP-AS1 regulates the cartilage repair in osteoarthritis, but how it regulates osteogenic differentiation of dental pulp stem cells (DPSCs) remains to be determined. DPSCs were isolated and induced for osteogenic differentiation. MCM3AP-AS1 expression was increased along with the osteogenic differentiation of DPSCs, whose expression was positive correlated with those of OCN, alkaline phosphatase (ALP) and RUNX2. On contrary, miR-143-3p expression was decreased along with the osteogenic differentiation and was negatively correlated with those of OCN, ALP and RUNX2. Dual-luciferase reporter gene assay showed that miR-143-3p can be negatively regulated by MCM3AP-AS1 and can regulate IGFBP5. MCM3AP-AS1 overexpression increased the expression levels of osteogenesis-specific genes, ALP activity and mineralized nodules during DPSC osteogenic differentiation, while IGFBP5 knockdown or miR-143-3p overexpression counteracted the effect of MCM3AP-AS1 overexpression in DPSCs. Therefore, this study demonstrated the role of MCM3AP-AS1/miR-143-3p/IGFBP5 axis in regulating DPSC osteogenic differentiation.

The Human Amniotic Mesenchymal Stem Cells (hAMSCs) Improve the Implant Osseointegration and Bone Regeneration in Maxillary Sinus Floor Elevation in Rabbits.

Insufficient bone height in the posterior maxilla is a challenging problem in dental implantation. Bio-Oss, though routinely used in maxillary sinus floor elevation (MSFE), is not osteoinductive. Human amniotic mesenchymal cells (hAMSCs) isolated from placental tissues have potential for multidifferentiation and immunomodulatory properties and can be easily obtained without the need for invasive procedures and without ethical concerns. This is the first study to use hAMSCs to improve implant osseointegration and bone regeneration after MSFE. Human AMSCs were loaded into a fibrin gel and injected into rabbit MSFE models. The rabbits were assigned to four groups (n = 3 per group), i.e., the control group, the hAMSC group, the Bio-Oss group, and the hAMSC/Bio-Oss group. The animals were sacrificed at postsurgery for four and twelve weeks and evaluated by histology and immunohistochemistry. Bone volume, bone volume/tissue volume, bone-to-implant contact ratio, and vessel-like structures in the hAMSC/Bio-Oss group were significantly better than those in other groups in the peri-implant and augmented areas. Immunofluorescence staining showed that alkaline phosphatase (ALP) activities of two hAMSC groups were higher than those of the other two groups. Sequential fluorescent labeling was performed in all of the 12-week groups. Observations showed that hAMSCs accelerated mineralized deposition rates on implant surfaces and in bone-augmented areas. These data demonstrated that hAMSCs could enhance implant osseointegration and bone regeneration after MSFE and might be used to optimize dental implantation in the future.

Dual-inflammatory cytokines on TiO2 nanotube-coated surfaces used for regulating macrophage polarization in bone implants.

Excessive immune responses following the use of implantable, biomaterial-based medical devices represent a substantial challenge for treatment efficacy and patient well-being. Specifically, after implantation, pro-inflammatory M1 macrophages are activated by cytokines such as interferon-γ (IFN-γ) followed by anti-inflammatory M2 macrophages polarized by cytokines including interleukin-4 (IL-4), leading to healing and long-term stability of implants. Here, we report the loading of an immunomodulatory cytokine,IL-4, into TiO2 nanotubes (TNTs) followed by hydrogel coating on the TNTs for subsequent release of IL-4. Finally, IFN-γ was added onto the gel layer to effect rapid release. The release rates of both cytokines from the samples were monitored using an immersion test in phosphate-buffered solution. The cytocompatibility of the sample was evaluated using cultures of osteoblasts and macrophages. Macrophage phenotype switching in vitro was examined via cytokine secretion and gene expression analyses. In vitro testing showed that the sample could stimulate macrophage polarization from the M1 to M2 phenotype at the desired period owing to temporal release of IFN-γ and IL-4. Another biomaterial containing only IL-4 in TNTs was also able to modulate the transformation of M1 to M2 although with weaker effect than that containing IFN-γ and IL-4. The biomaterial may be useful as an osteoimplant in vivo owing to the inflammation caused by a wound or implantation. This study provided biomaterials capable of facilitating smooth M1 to M2 macrophages switching, which might be helpful to research immune responses of tissues to implants and will likely contribute to the development of bone substitute materials. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1878-1886, 2018.

Directing the Differentiation of Parthenogenetic Stem Cells into Tenocytes for Tissue-Engineered Tendon Regeneration.

Uniparental parthenogenesis yields pluripotent stem cells without the political and ethical concerns surrounding the use of embryonic stem cells (ESCs) for biomedical applications. In the current study, we hypothesized that parthenogenetic stem cells (pSCs) could be directed to differentiate into tenocytes and applied for tissue-engineered tendon. We showed that pSCs displayed fundamental properties similar to those of ESCs, including pluripotency, clonogenicity, and self-renewal capacity. pSCs spontaneously differentiated into parthenogenetic mesenchymal stem cells (pMSCs), which were positive for mesenchymal stem cell surface markers and possessed osteogenic, chondrogenic, and adipogenic potential. Then, mechanical stretch was applied to improve the tenogenic differentiation of pMSCs, as indicated by the expression of tenogenic-specific markers and an increasing COL1A1:3A1 ratio. The pSC-derived tenocytes could proliferate and secrete extracellular matrix on the surface of poly(lactic-co-glycolic) acid scaffolds. Finally, engineered tendon-like tissue was successfully generated after in vivo heterotopic implantation of a tenocyte-scaffold composite. In conclusion, our experiment introduced an effective and practical strategy for applying pSCs for tendon regeneration. Stem Cells Translational Medicine 2017;6:196-208.

A colorimetric aptamer biosensor based on cationic polymer and gold nanoparticles for the ultrasensitive detection of thrombin.

A colorimetric assay for the ultrasensitive determination of thrombin based on cationic polymer and gold nanoparticles was presented, in which unmodified gold nanoparticles (AuNPs) was used as probes and 21-mer thrombin-binding aptamer (TBA) as sensing elements. Upon the addition of thrombin, TBA interacted specifically with thrombin to form a G-quadruplex structure. As a result, the conformation change facilitated the cationic polymer, poly(diallyldimethylammonium chloride) (PDDA)-induced AuNP aggregation. Thus, the visible change in color from wine-red to blue-purple was readily seen by the naked eye. The colorimetric sensor could detect thrombin down to 1 pM with high selectivity in the presence of other interferring proteins. Furthermore, the assay was successfully employed to determine thrombin in human serum sample, which suggested its great potential for diagnostic purposes.

[Effects of tooth whitening agents and acidic drinks on the surface properties of dental enamel].

OBJECTIVE: Using tooth whitening agents (bleaching clip) in vitro and acidic drinks, we conducted a comparative study of the changes in enamel surface morphology, Ca/P content, and hardness. METHODS: Tooth whitening glue pieces, cola, and orange juice were used to soak teeth in artificial saliva in vitro. Physiological saline was used as a control treatment. The morphology of the four groups was observed under a scanning electron microscope (SEM) immediately after the teeth were soaked for 7 and 14 d. The changes in Ca/P content and microhardness were analyzed. RESULTS: The enamel surfaces of the teeth in the three test groups were demineralized. The Ca/P ratio and the average microhardness were significantly lower than those of the control group immediately after the teeth were soaked (P < 0.05). The Ca/P ratio and microhardness gradually increased after 7 d. No significant difference was observed between the control group and the test groups after 14 d (P > 0.05). CONCLUSION: Bleaching agents caused transient demineralization of human enamel, but these agents could induce re-mineralization and repair of enamel over time. Demineralization caused by bleaching covered a relatively normal range compared with acidic drinks and daily drinking.

[Biodegradation of lignocellulose by Penicillium simplicissimum and characters of lignocellulolytic enzymes].

Penicillium simplicissimum(Oudem.) Thomrn BGA can secrete lignocellulolytic enzymes, among these enzymes the highest activities of hemicellulase, cellulase, lignin peroxidase (Lip), manganese peroxidase (Mnp) and laccase are 146.82 Iu.g-1, 2.78 U.g-1, 47.97 U.g-1, 34.56 U.g-1 and 17.94 U.g-1 respectively. According to the results and the statistical analysis of SPSS, the ability of secreting lignocellulolytic enzymes by Penicillium simplicissimum significantly correlated with the structure of lignocellulose, and the biodegradation of lignocellulose was probably a kind of synergistic effect of several lignocellulolytic enzymes. In the solid-state fermentation of 30 days, the hemicellulose content has a significantly negative correlation with the fermentation days(r = -0.946, P < 0.01), there was also a significantly negative correlation between the cellulose-biodegradation and the lignin-biodegradation (r = -0.818, P<0.05). As unselected enzymes, Lip and Mnp can degrade hemicellulose and cellulose corporately when biodegrades lignin. The significant correlation is showed between Lip, Mnp and cellulose (correlation parameters are r = 0. 922, P <0.01; r = 0.807, P<0.05 respectively). In addition, the biosorption is found to have a very important effect in the removal of liquid alkali lignin by Penicillium simplicissimum. Key words:Penicillium simplicissimum; lignocellulolytic enzymes; biodegradation; biosorption; synergistic effect

[The change of bacterial adhesion during deposition nitrogen-diamond like carbon coating on pure titanium].

OBJECTIVE: The aim of this study was to observe the change of bacterial adhesion on pure titanium coated with nitrogen-diamond like carbon (N-DLC) films and to guide the clinical application. METHODS: N-DLC was deposited on titanium using ion plating machine, TiN film, anodic oxide film and non-deposition were used as control, then made specimens adhering on the surface of resin denture base for 6 months. The adhesion of Saccharomyces albicans on the titanium surface was observed using scanning electron microscope, and the roughness was tested by roughness detector. RESULTS: The number of Saccharomyces albicans adhering on diamond-like carbon film was significantly less than on the other groups (P < 0.05), and the growth of bacterial cell was inhibited and in a poor state. The largest number of adhesion and cell strains grew well on anodic oxide film group and non-deposition control group. The change of surface roughness of N-DLC film was less than other group (P < 0.05). CONCLUSION: Pure titanium coated with N-DLC film reduced the adhesion of Saccharomyces albicans after clinical application, thereby reduced the risk of denture stomatitis.

[A survey of perception differences of malocclusion between 16 to 22-year-old young adults and orthodontists].

OBJECTIVE: To investigate 16 to 22-year-old young adults' perception of malocclusion, dental health and aesthetic firstly. To investigate the perception differences between young adults and orthodontists, and factors on perception difference. METHODS: A sample of 16 to 22-year-old young adults was selected randomly in Department of Stomatology, Hospital of Nanjing Army Command College. A questionnaire, which consisted of socioeconomic status, index of orthodontic treatment need and dental health component (DHC) questionnaire, was proposed to them. Index of orthodontic treatment need comprised aesthetic component (AC) and DHC. An orthodontist measured orthodontic dental models of participants. Participants chose AC degree and DHC degree by their subjective perception. An orthodontist chose AC degree and DHC degree by their objective measurement. RESULTS: 71.08% and 70.59% of 204 participants respectively chose 'no need treatment' of AC degree and DHC degree by their subjective perception. 19.12% and 9.80% of participants were respectively chosen 'no need treatment' of AC degree and DHC degree by orthodontist's objective measurement. Objective measurement degree of orthodontist was higher than subjective perception degree of participants. Subjective perception of participants was little related to objective measurement of orthodontists. AC degree of male participants' subjective perception was lower than the female. DHC degree of urban participants' subjective perception was higher than the rural. DHC and AC degree of only child participants' subjective perception was higher than non-only child. CONCLUSION: Perception about malocclusion, dental health and aesthetic had significant difference between 16 to 22-year-old young adults and orthodontists. Young adults tended to think that their teeth were more beautiful and healthy. The female young adults than the male tended to think that their teeth were not enough beautiful. Urban young adults were more unsatisfactory about their dental health than the rural. Only child young adults were more unsatisfactory about their dental aesthetic and health than the non-only child.

[Study of nitrogen silicon zirconium-hydroxylapatite as a coating on pure titanium implantation].

OBJECTIVE: To compare the osseointegration and corrosion of different kind of coatings on pure titanium. METHODS: By plasma spraying technology, nitrogen silicon zirconium-hydroxylapatite (ZrSiN-HA) compound coating was prepared on the surface of pure titanium and the pure titanium was implanted with the mandible of the experimental animal. The superficial appearance of the compound coating was observed and analyzed by scanning electron microscope (SEM). The ZrSiN-HA, nitrogen silicon zirconium (ZrSiN), hydroxylapatite (HA) and pure titanium were compared and examined. In the four groups, the bone binding force of coatings were detected, and the superficial appearance of the break regions were observed by the electronic multipurpose material testing aircraft. In the four groups, the anticorrosive of coatings were compared and examined on the electrochemistry corrosion testing system. RESULTS: Experimental results indicated that the implant surface sprayed with the ZrSiN-HA was more compact than that sprayed with HA. The crystallization was obvious. Compared with the other coatings, the bone binding force of the ZrSiN-HA coating was the highest, and its anticorrosive performance was the strongest. CONCLUSION: The application of ZrSiN-HA coating is advantageous to the long-term retention of implant, and it has huge latent application value to dental dummy.

[Study of TiN plating coat on increasing shear bond strength].

PURPOSE: To investigate the feasibility of increasing bond strength of polymer ceramic to titanium using TiN coating. METHODS: Twelve pure titanium specimens were casted and divided into two groups randomly. In one group,the surface was processed with conventional handling,in the other group,the surface was coated with TiN. Then the specimens in each group was bonded with polymer ceramic material (Ceramage). The shear bond strength was measured using parallel interface shearing. The interface between polymer ceramic and titanium was observed under SEM. Two samples t test was conducted with SPSS11.0 software package. RESULTS: The shear bond strength of TiN plating coat group was (29.78+/-0.78)MPa, larger than that of the conventional handling group (25.73+/-0.37)MPa, the difference was significant (P<0.01) between the two groups, and both of them exceeded ISO9693:1999(P<0.01). CONCLUSION: TiN plating coat can effectively improve the shear bond strength.