Graphene nanocoating provides superb long-lasting corrosion protection to titanium alloy

ObjectiveThe presence of metallic species around failed implants raises concerns about the stability of titanium alloy (Ti-6Al-4V). Graphene nanocoating on titanium alloy (GN) has promising anti-corrosion properties, but its long-term protective potential and structural stability remains unknown. The objective was to determine GN’s anti-corrosion potential and stability over time.MethodsGN and uncoated titanium alloy (Control) were challenged with a highly acidic fluorinated corrosive medium (pH 2.0) for up to 240 days. The samples were periodically tested using potentiodynamic polarization curves, electrochemical impedance spectroscopy and inductively coupled plasma-atomic emission spectroscopy (elemental release). The integrity of samples was determined using Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and scanning electron microscopy. Statistical analyses were performed with one-sample t-test, paired t-test and one-way ANOVA with Tukey post-hoc test with a pre-set significance level of 5%.ResultsThere was negligible corrosion and elemental loss on GN. After 240 days of corrosion challenge, the corrosion rate and roughness increased by two and twelve times for the Control whereas remained unchanged for GN. The nanocoating presented remarkably high structural integrity and coverage area (>98%) at all time points tested.SignificanceGraphene nanocoating protects titanium alloy from corrosion and dissolution over a long period while maintaining high structural integrity. This coating has promising potential for persistent protection of titanium and potentially other metallic alloys against corrosion.     

碳纤维头超声洁治术治疗种植体周围炎的效果评估

目的:分析碳纤维头超声洁治术对种植体周围炎的治疗效果.方法:选取医院收治的30例牙周炎患者,采用随机数表法将其分为对照组和观察组,每组15例,对照组通过生理盐水漱口方式清洗种植体,观察组采用碳纤维头超声洁治术对种植体进行洁治.两组连续治疗2个疗程后,比较种植体周围组织的牙周改良菌斑指数(mPLI)、牙龈指数(GI)、临...     

Titanium particles: An emerging risk factor for peri-implant bone loss

ObjectiveTo investigate the presence of titanium particles in peri-implant tissues in cases diagnosed with peri-implantitis, and to identify immunological reactions that these particles may elicit.MethodsTen peri-implant tissue biopsies of patients diagnosed clinically and radiographically with peri-implantitis were obtained from the archives of Oral Pathology Centre, University of Otago. The inclusion criteria involves: bleeding on probing, ≥6 mm probing depth and ≥3 mm radiographic bone loss around the dental implant. Peri-implant tissue samples were evaluated using scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) to identify of sites with/without titanium particles. Antibodies against human transforming growth factor beta 1 (TGF-β1), receptor activator of nuclear factor kappa-B ligand (RANKL), interleukin 33 (IL-33) and cluster of differentiation 68 (CD68) were used to stain the specimens. ImageJ software was used to standardise the sampling area, compare and characterise the inflammatory infiltrate in tissues with/without titanium particles. Inflammatory cytokines positivity was assessed using the immunoreactive scores (IRSs).ResultsLight microscopy and SEM-EDS analysis identified titanium wear particles in 90% of the tissue samples, associated with a mixed chronic inflammatory infiltrate. Quantification analysis of RANKL revealed significantly higher IRS and intensity scores (p < 0.05) in areas containing titanium. High intensity, proportion and IRSs of TGF-β1 and IL-33 were observed in areas with titanium. CD68 had higher IRSs in the absence of titanium particles.ConclusionsSignificant overexpression of the cytokine RANKL was observed, with a trend for over-expression of IL-33 and TGF-B1 in areas with titanium. Further studies with large sample size and appropriate control group for quantification analysis is needed to confirm the role of titanium particles in initiating bone loss.     

种植体周围炎龈沟液中IL-2、IFN-γ、IL-4、IL-6的表达及临床意义

目的探讨探讨白细胞介素2、4、6(IL-2、IL-4、IL-6)、干扰素γ(IFN-γ)在种植体周围炎龈沟液(GCF)中的表达及意义。方法选择2011年6月~2014年6月50例种植体周围炎患者为研究对象。另选择健康种植体患者50例和健康人群50例为对照组。统计3组探诊深度(PD)、龈沟出血指数(SBI)、IL-2、IFN-γ、IL-4、IL-6水平。结果种植体周围炎组PD、SBI、GCF均高于健康种植体组和对照组,差异有统计学意义(P<0.01);但健康种植体组和对照组PD、SBI、GCF差异无统计学意义(P>0.05);种植体周围炎组IL-2、IFN-γ水平低于健康种植体组和对照组(P<0.01),健康种植体组IL-2、IFN-γ水平低于对照组(P<0.05),种植体周围炎组IL-4、IL-6水平高于健康种植体组和对照组(P<0.01),健康种植体组IL-4、IL-6水平高于对照组(P<0.05); ≥60岁组IL-2、IFN-γ水平低于<60岁组(P<0.01), ≥60岁组IL-4、IL-6水平高于<60岁组(P<0.01);种植体周围炎患者GCF中IL-2与IFN-γ呈正相关(r=4.267, P=0.016),与IL-4、IL-6分别呈负相关(r=4.352、4.615,P=0.005、0.002),IFN-γ与IL-4、IL-6分别呈负相关(r=4.322、4.603,P=0.009、0.005),IL-4,IL-6呈正相关(r=4.065, P=0.019)。结论种植体周围炎患者IL-4、IL-6高表达,IL-2、IFN-γ低表达,IL-2、IFN-γ、IL-4、IL-6的表达与种植体周围炎患者性别无关,与种植体周围炎患者的年龄有关。     

SLA种植体表面喷涂钽形成纳米复合表面预防种植术后早期感染的动物体内实验研究

目的　探讨大颗粒酸蚀喷砂（Sandblasted/Large-grit/Acide -tched,SLA）表面处理的种植体与SLA表面喷涂钽（Ta）形成纳米复合表面的种植体对种植体周围炎发生发展的影响。 方法　6只Beagle犬双侧前磨牙延期植入2种不同表面种植体。从左侧远中到右侧远中依次将植体记为1~6号,3、4号种植体设置非绑线的基线组,其余于基台颈部丝线结扎的方法建立犬种植体周围炎模型。分别在建模后四次对植体进行菌斑指数（plaque index, PI）、改良出血指数（modified Sulcus Bleeding Index, mSBI）、种植体周探诊深度（probing depth, PD）等临床指标测量,通过手术直观评价、显微CT扫描、组织学评价相结合观察种植体周骨缺损程度,对实验结果采用重复测量方差分析。 结果　绑线的SLA组PI、mSBI、PD、垂直缺损与水平缺损深度等指标均显著高于绑线的SLA+Ta组（P<0.05）;显微CT扫描和组织学评价相结合观察可见绑线的SLA组较绑线的SLA+Ta组种植体周骨缺损明显。 结论　SLA表面喷涂钽形成纳米复合表面的种植体较SLA表面处理的种植体延缓种植体周围炎的发生发展并减轻其症状。     

维生素D受体基因TagⅠ和BsmⅠ位点单核苷酸多态性与种植体周围炎的易感性研究

目的研究维生素D受体(vitamin D receptor,VDR)基因TagⅠ和BsmⅠ位点单核苷酸多态性与种植体周围炎易感性的关系。方法采用病例对照试验设计,收集种植体周围炎组及无种植体周围炎组各50例,应用聚合酶链反应—限制性内切酶片段长度多态性分析方法研究2组VDRTagⅠ和BsmⅠ位点的基因型以及等位基因分布特点,并探讨其与种植体周围炎的相关性。结果 VDR基因BsmⅠ位点各基因型(χ2=3.184,P=0.074)和等位基因频率(χ2=3.269,P=0.071)在2组间分布差异无统计学意义。VDR基因TagⅠ位点主要基因型为TT纯合子和Tt杂合子,2种基因型(χ2=4.337,P=0.037)和T、t等位基因频率(χ2=3.907,P=0.048)在2组的分布差异具有统计学意义。TT型在种植体周围炎组中较为多见。结论避免吸烟、牙周炎病史等混杂因素后,种植体周围炎与VDRTaqI位点单核苷酸多态性间存在遗传相关性,尚不能认为与BsmⅠ位点的多态性相关。     

What is the role of biofilms in severe head and neck infections?

Most infections of the head and neck and virtually all of those encountered in the practice of dentistry are caused by bacteria that are organized into biofilms. A biofilm is a complex, usually multispecies, highly communicative community of bacteria that is surrounded by a polymeric matrix. Treatment of these types of infections with traditional antibiotics alone is ineffective, and surgical removal of diseased tissue is still necessary.     

氯己定联合机械清创对种植体周围炎的治疗效果及对患者SF-36评分的影响

目的：研究氯己定联合机械清创对种植体周围炎的治疗效果及对患者SF-36评分的影响。方法：选取2015年1月—2019年1月浙江省人民医院收治的种植体周围炎患者100例,按照随机数字表法随机分为对照组和联合组各50例。2组患者均采用机械清创术进行治疗,联合组在机械清创术后使用氯己定漱口液含漱。对2组患者治疗前、后菌斑生物膜不同层面平均活性、改良菌斑指数（modified plaque index,mPLI）、探诊后出血指数（bleeding on probing,BOP）、改良龈沟出血指数（modification sulcus bleeding index,mSBI）、探诊深度（probing depth,PPD）、临床附着水平（clinical attachment level,AL）进行评价,并使用SF-36评分量表、VAS视觉疼痛评分法对2组患者生活质量、疼痛程度进行评价,评定治疗效果及统计并发症发生情况。采用SPSS 20.0软件包对数据进行统计学分析。结果：治疗前2组患者菌斑生物膜不同层面平均活性、mPLI、mSBI、AL、PPD、BOP、VAS、SF-36评分比较,无显著差异（P>0.05）;治疗后联合组患者菌斑生物膜不同层面平均活性、mPLI、mSBI、AL、PPD、BOP、VAS评分均低于对照组,SF-36评分高于对照组,治疗总有效率显著高于对照组（P<0.05）。联合组患者治疗过程中并发症发生率显著低于对照组（P<0.05）。结论：氯己定联合机械清创对种植体周围炎患者进行治疗,效果显著,可有效抑制菌斑生物膜活性,抑制菌斑形成,减轻患者疼痛,提高生活质量。