Effect of Surface Tooling Techniques of Medical Titanium Implants on Bacterial Biofilm Formation In Vitro

The aim of this study was to assess the biofilm formation of Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli on titanium implants with CAD-CAM tooling techniques. Twenty specimens of titanium were studied: Titanium grade 2 tooled with a Planmeca CAD-CAM milling device (TiGrade 2), Ti₆Al₄V grade 5 as it comes from CAD-DMLS device (computer aided design-direct metal laser sintering device) (TiGrade 5), Ti₆Al₄V grade 23 as it comes from a CAD-CAM milling device (TiGrade 23), and CAD-DMLS TiGrade 5 polished with an abrasive disc (TiGrade 5 polished). Bacterial adhesion on the implants was completed with and without saliva treatment to mimic both extraoral and intraoral surgical methods of implant placement. Five specimens/implant types were used in the bacterial adhesion experiments. Autoclaved implant specimens were placed in petri plates and immersed in saliva solution for 30 min at room temperature and then washed 3× with 1× PBS. Bacterial suspensions of each strain were made and added to the specimens after saliva treatment. Biofilm was allowed to form for 24 h at 37 °C and the adhered bacteria was calculated. Tooling techniques had an insignificant effect on the bacterial adhesion by all the bacterial strains studied. However, there was a significant difference in biofilm formation between the saliva-treated and non-saliva-treated implants. Saliva contamination enhanced S. mutans, S. aureus, and E. faecalis adhesion in all material types studied. S. aureus was found to be the most adherent strain in the saliva-treated group, whereas E. coli was the most adherent strain in the non-saliva-treated group. In conclusion, CAD-CAM tooling techniques have little effect on bacterial adhesion. Saliva coating enhances the biofilm formation; therefore, saliva contamination of the implant must be minimized during implant placement. Further extensive studies are needed to evaluate the effects of surface treatments of the titanium implant on soft tissue response and to prevent the factors causing implant infection and failure.     

Electrochemical Evaluation of Stress Corrosion Cracking Susceptibility of Ti-6Al-3Nb-2Zr-1Mo Alloy Welded Joint in Simulated Deep-Sea Environment

Titanium alloys have high specific strength and excellent corrosion resistance and have been applied in deep-sea engineering fields. However, stress corrosion cracking may become one of the biggest threats to the service safety of a high-strength titanium alloy, as well as its weldment. In this work, stress corrosion cracking of a gas-tungsten-arc-welded Ti-6Al-3Nb-2Zr-1Mo (Ti6321) alloy influenced by the applied potentials in simulated deep-sea and shallow-sea environments was investigated by combining slow strain rate testing with electrochemical measurements. The results showed that the service environment and applied potential have a substantial effect on the stress corrosion cracking behavior of the Ti6321 welded joint. The Ti6321 welded joint exhibited higher stress corrosion susceptibility in a simulated deep-sea environment and at a strong polarization level owing to the diminishing protection of the passive film under passivation inhibition and the enhancement of the hydrogen effect. The fracture of a Ti6321 welded joint in the weld material could be attributed to the softening effect of the thick secondary α within the coarse-grained martensite. The electrochemical evaluation model of stress corrosion cracking susceptibility of a Ti6321 welded joint in a simulated marine environment was established by adding the criterion in the passivation region based on the literature model, and four potential regions corresponding to different stress corrosion cracking mechanisms were classified and discussed. Our study provides useful guidance for the deep-sea engineering applications of Ti6321 alloys and a rapid assessment method of stress corrosion risk.     

化学气相淀积反应器中超细粒子的形态控制 Ⅲ.TiO_2超细粒子晶体组成

在超细粒子粒度及粒度分布控制模型的基础上,对快相变速率和慢相变速率两种晶型转变情形,建立了化学气相淀积合成超细粒子过程中,表征超细粒子晶体组成及含量的物理模型和数学模型。利用该模型探讨了物系参数和操作参数对超细粒子晶体组成的影响,理论预测和实验结果相一致。     

Professional Burnout:

This paper attempts to answer the question of why social caseworkers have ongoing supervision by exploring the historical evolution of social work supervision. Supervision has withstood the many changes in the field since its beginning in the late 1800s and has been reinterpreted to fit the prevailing theories guiding practice, thus avoiding obsolescence. Supervision began as an educational device, then evolved into a practice tool, later became a therapeutic method, and then became a separate entity from therapy.     

颌间牵引钉对比牙弓夹板颌间牵引联合微型钛板坚固内固定治疗颌骨骨折临床分析

目的：探讨颌间牵引钉对比牙弓夹板行颌间牵引术联合微型钛板坚固内固定治疗颌骨骨折的临床疗效对比观察。方法：将2007年-2011年收治的82例颌骨骨折患者随即分为颌间牵引钉纽和牙弓夹板组,牙弓夹板组采用微型钛板坚固内固定联合牙弓夹板牵引治疗,颌间牵引钉组采用微型钛板坚固内固定联合颌间牵引钉牵引治疗。治疗后比较术后疗效;并在5个时间点测定DI、GI、CPITN指数。结果：经治疗后颌间牵引钉组总有效率为85．37％,牙夹板组总有效率为和78．02％,颌间牵引钉组总体疗效优于牙弓夹板组（Х^2=10．015,P〈0．05）;2组的DI、GI指数经治疗后均上升,但牙弓夹板组上升显著（P〈0．01）;术后两组CPITN指数。颌间牵引钉纽基本无变化,牙弓夹板纽显著升高（P〈0．01）。结论：领间牵引钉领间牵引联合微型钛板坚固内固定治疗领骨骨折治愈率高、治疗过程安全且对牙周组织不良刺激小。适合进行临床推广。     

后腹腔镜水刀辅助零阻断肾部分切除术治疗T_(1a)肾肿瘤的临床体会(附8例报告)

目的:探讨后腹腔镜水刀辅助零阻断肾部分切除术治疗T1a期肾肿瘤的临床经验与疗效。方法:回顾分析2011年10月至2012年11月8例T1a期肾肿瘤患者的临床资料,其中男6例,女2例,平均(38.2±10.4)岁,左侧5例,右侧3例;肿瘤直径平均(2.8±0.9)cm。8例患者均行后腹腔镜水刀辅助零阻断肾部分切除术。结果:8例手术均顺利完成,无一例中转开放手术,围手术期无严重并发症发生。手术时间平均(103.2±24.5)min,术中出血量平均(250.3±80.6)ml,肾周引流管平均留置(6.3±2.6)d,术后平均住院(8.3±1.6)d。术后平均随访(5.2±2.1)个月,患者肾功能正常,未见肿瘤复发及转移。结论:后腹腔镜水刀辅助零阻断肾部分切除术治疗T1a肾肿瘤安全、有效、患者创伤小,可避免残留肾脏组织的热缺血及缺血再灌注损伤,在肿瘤彻底切除的基础上肾功能得到最大限度地保留;但远期疗效尚需大样本研究及长期随访。     

Results of titanium locking plate and stainless steel cerclage wire combination in femoral fractures

Background:

Some in vitro studies warn combining different metals in orthopedic surgery. The aim of this study is to determine the impact of combining titanium and stainless steel on bone healing and the clinical course of patients undergoing internal fixation of femoral fractures.

Materials and Methods:

69 patients with femoral fractures had polyaxial locking plate osteosynthesis. The locking plate was made of a titanium alloy. Two different cohorts were defined: (a) sole plating and (b) additional stainless steel cerclage wiring. Postoperative radiographs and clinical followup were performed at 6 weeks, 3 months and 12 months.

Results:

Cohorts A and B had 36 and 33 patients, respectively. Patient demographics and comorbidities were similar in both groups. In two cases in cohort A, surgical revision was necessary. No complication could be attributed to the combination of titanium and stainless steel.

Conclusion:

The combination of stainless steel cerclage wires and titanium plates does not compromise fracture healing or the postoperative clinical course.     

Complications associated with cervical vertebral body replacement with expandable titanium cages

Our aim was to analyze complications and risk factors for cervical vertebral body replacement (VBR) with expandable titanium cages (ETC). Fifty patients; 22 women and 28 men, mean age 61 years, undergoing cervical VBR from 2010 to 2015 were analyzed. Complications were stratified by hardware-association (HA). Univariate and multivariate logistic regression was used to identify independent risk factors. Single, two and three level corpectomies were performed in 32, 15 and 3 patients respectively. A circumferential approach was necessary in 16 cases. At mean follow-up (7.3 months) 66% of patients had recovered. Radiological data showed a significant distraction (2.60 mm, p < 0.0001) and lordosis (5°, p = 0.001). Twenty-three patients experienced 42 complications; 18 HA, 24 non-HA and 24% needed revision surgery. The number of corpectomy levels and surgical approach significantly correlated with the risk of complications (p = 0.001), especially non-HA complications (p = 0.002). On multivariate analysis, only the number of corpectomy levels (p < 0.02, odds ratio 5.48, 95% CI 1.31–22.91) was a significant predictor of complications. We conclude that ETC are efficacious devices for cervical spine VBR, however, when used for more than 1 level, the corpectomy complication rate significantly increases.     

前路减压钛网植骨内固定治疗胸腰椎爆裂骨折疗效观察

目的探讨前路减压钛网植骨钢板内固定治疗胸腰椎爆裂骨折的疗效。方法对85例胸腰椎爆裂骨折患者采用胸膜外腹膜后入路前路减压钛网植骨钢板内固定。结果手术均顺利完成,手术时间120～190min,术中出血量500～1 500 ml。85例均获随访,时间5～72个月。患者植骨均融合,椎体高度无丢失,钛网及钢板无移位断裂。术前59例神经功能损伤患者末次随访时37例ASIA分级有1～2级恢复,无加重病例。结论前路减压钛网植骨内固定治疗不稳定性胸腰椎爆裂骨折减压彻底,固定牢靠,疗效肯定。     

椎弓根钉固定椎体次全切钛网重建治疗腰椎爆裂骨折

目的探讨经后路椎弓根钉固定,椎管减压加椎体次全切钛网重建治疗腰椎爆裂骨折的疗效及预后。方法 2008年1月至2010年1月,采用一期经后路单侧行椎体次全切除、脊髓环形减压、钛网支撑植骨重建前中柱及椎弓根钉固定后柱治疗腰椎爆裂骨折18例,其中男13例,女5例;年龄20～55岁,平均38.6岁。均为单椎体爆裂骨折,L13例,L27例,L36例,L41例,L51例。采用美国脊柱损伤学会分级进行神经功能评估。通过X线和CT评估手术前后及末次随访时伤椎椎体高度、椎管内径及骨融合情况。结果手术均顺利完成,手术时间2.5～4.5h,平均3.7h。出血量680～1 500mL,平均980mL。术后发生脑脊液漏3例,无其他严重并发症发生。所有病例均获随访,时间12～36个月,平均25个月,内固定无松动、断裂,钛网重建节段获得骨性融合,椎体的高度、曲度和椎管容积无明显丢失,无感染及医源性神经损伤等并发症。除1例A级患者外,其他患者神经功能均有不同程度的恢复。结论经后路椎弓根钉固定加椎体次全切重建脊柱三柱稳定性手术具有手术操作相对简便、创伤小、脊髓减压彻底、脊柱前中后柱即刻稳定、并发症少等特点,是腰椎爆裂骨折的一种有效治疗方法。