热激活镍钛弓丝和普通镍钛弓丝在正畸治疗中的效果比较

目的比较热激活镍钛弓丝与普通镍钛弓丝在正畸治疗中的的疗效差异。方法选取2014年1月~2016年1月我院42例实施正畸治疗的患者,随机分为研究组和对照组,每组21例。对照组给予普通镍钛弓丝正畸治疗,研究组患者给予热激活镍钛弓丝治疗,对两组的排齐整平时间、弓丝断裂次数、托槽脱落次数、治疗总时间、视觉模拟评分法(VAS)疼痛评分情况及不良反应情况进行观察比较。结果研究组的排齐整平时间、治疗总时间分别为(18.48±2.13)w、(82.43±5.26)w,短于对照组的(24.83±2.66)w、(91.61±6.62)w(P0.05);研究组的弓丝断裂次数、托槽脱落次数均较对照组少(P0.05);治疗后研究组的VAS评分较对照组低(P0.05);两组均无炎症、过敏等不良反应,耐受性好。结论热激活镍钛弓丝在正畸治疗中效果确切,可显著减少弓丝断裂次数,节省治疗时间,减轻疼痛反应,优于普通镍钛弓丝,值得临床推广。     

四种镍钛正畸弓丝表面微观结构的改变

背景:镍钛弓丝的腐蚀表现与其生物安全性及摩擦性能有着密切的关系,国外关于此方面的研究较多,但结果不完全一致.目的:了解不同品牌镍钛弓丝的抗腐蚀性.设计、时间及地点:对比观察实验,于2008-09/12在新疆医科大学基础医学院科研中心实验室和电镜室完成.材料:北京圣玛特科技有限公司(SMT)、深圳市速航科技有限公司(SH)、3M Company U.S.A(3M)、托博正畸器械(无锡)有限公司(TP)生产的热激活型镍钛合金矫形丝,型号为上颌卵圆形.方法:配制人工唾液并调节pH值分别为4.0及6.75,剪取4种不同品牌的镍钛弓丝末端较直的部分放入人工唾液中,并保持温度在37℃.主要观察指标:分别于浸泡1,7,28 d时取出样本,使用扫描电镜对样本的表面结构进行观察.结果:上述4种品牌的的镍钛弓丝经过浸泡后,表面结构均发生了不同程度的改变,其中SL、SMT组的改变程度较3M、TP组明显.各品牌存pH 4.0人工唾液中的改变程度大于pH 6.75,并随着浸泡人数的增加表面结构的变化越明显.结论:①酸性环境加速了镍钛弓丝的腐蚀,并随着浸泡人数的增加腐蚀改变的程度越大.②不同品牌的镍钛弓丝所表现出的腐蚀形式和程度不完全相同.     

口腔正畸用镍钛弓丝的腐蚀性及防腐蚀

背景:口腔正畸用镍钛弓丝临床使用后期常发生弓丝力学性能降低现象,严重影响了临床治疗效果,有研究表明口腔唾液电解质环境腐蚀是影响其性能的主要因素之一.目的:综述近年国内外关于口腔正畸用镍钛弓丝腐蚀性研究的进展.方法:采用计算机检索中国知网数据库CNKI 1995-01/2010-10,PubMed数据库和Elsevier(ScienceDirect)数据库1975-01/2010-10与正畸用镍钛弓丝腐蚀性相关得研究.结果与结论:在复杂的口腔环境中,温度、负载、氟离子等因素均能加速对正畸用镍钛弓丝的腐蚀,不同程度地影响正畸用镍钛弓丝的性能,降低正畸镍钛弓丝的机械性能,增大表面粗糙度进而延长了正畸治疗疗程,增加了正畸治疗成本.正畸用镍钛弓丝腐蚀所释放的镍离子降低了其生物安全性.防腐蚀处理能提高镍钛弓丝的抗腐蚀能力,主要应用表面处理技术,但目前安全有效的方法并不多,对正畸用镍钛弓丝的腐蚀和防腐蚀还有待于进一步深入研究.     

口腔正畸用镍钛弓丝的腐蚀性及防腐蚀

背景：口腔正畸用镍钛弓丝临床使用后期常发生弓丝力学性能降低现象,严重影响了临床治疗效果,有研究表明口腔唾液电解质环境腐蚀是影响其性能的主要因素之一。目的：综述近年国内外关于口腔正畸用镍钛弓丝腐蚀性研究的进展。方法：采用计算机检索中国知网数据库CNKI 1995-01/2010-10,PubMed数据库和Elsevier（ScienceDirect）数据库1975-01/2010-10与正畸用镍钛弓丝腐蚀性相关得研究。结果与结论：在复杂的口腔环境中,温度、负载、氟离子等因素均能加速对正畸用镍钛弓丝的腐蚀,不同程度地影响正畸用镍钛弓丝的性能,降低正畸镍钛弓丝的机械性能,增大表面粗糙度进而延长了正畸治疗疗程,增加了正畸治疗成本。正畸用镍钛弓丝腐蚀所释放的镍离子降低了其生物安全性。防腐蚀处理能提高镍钛弓丝的抗腐蚀能力,主要应用表面处理技术,但目前安全有效的方法并不多,对正畸用镍钛弓丝的腐蚀和防腐蚀还有待于进一步深入研究。     

热激活镍钛弓丝与普通镍钛丝在正畸治疗中的评价

背景:热激活镍钛弓丝是一种新型弓丝,有良好的记忆合金功能,不易形变,外环境温度的改变可能会对其性能产生影响.目的:对比观察热激活镍钛弓丝与普通镍钛丝临床应用效果的差异.方法:选择中山大学附属第一医院进行正畸治疗并且完成治疗的患者80例,随机将样本分为2组.普通组在排齐和整平阶段用普通镍钛丝,激活组在排齐和整平阶段使用热激活镍钛丝.并且匹配拔牙和非拔牙病例.观察两组的排齐时间,总疗程时间,弓丝断裂次数,托槽脱落次数,就诊次数.结果与结论:热激活组的病例在矫正时间,弓丝断裂次数与对照组比较,均差异有显著性意义(P<0.05),托槽脱落次数差异无显著性意义.使用热激活镍钛丝患者未发生过敏反应、毒性反应等不良反应.结果提示,热激活镍钛弓丝在正畸治疗过程中可以节省弓丝更换次数和减少弓丝断裂,缩短治疗时间.     

氟离子和酸对3M镍钛弓丝和Damon铜镍钛弓丝耐腐蚀性的影响

背景：在含氟的酸性环境中,Damon铜镍钛弓丝能否具有与传统镍钛弓丝相当的耐腐蚀性能,铜离子的加入会不会影响其耐腐蚀性？目的：观察氟离子和酸对3M镍钛弓丝和Damon铜镍钛弓丝耐腐蚀性的影响。方法：采用动电位极化曲线法测得3M镍钛弓丝和Damon铜镍钛弓丝分别在4种（pH=7、不含氟离子;pH=7、含氟离子浓度0.2%;pH=7、含氟离子浓度0.5%;pH=5、含氟离子浓度0.5%）不同人工唾液中的动电位极化曲线,得到自腐蚀电位、自腐蚀电流密度和极化电阻,并用扫描电镜观察其腐蚀后的形态。结果与结论：在中性（pH=7）人工唾液中加入0.2%氟离子,Damon铜镍钛弓丝试件极化曲线上移,自腐蚀电流密度增大,极化电阻减小（P 〈0.05）,扫描电镜显示试件表面出现腐蚀;3M镍钛弓丝试件极化曲线没有偏移,自腐蚀电流密度、极化电阻基本不变（P〉0.05）,腐蚀不明显;当氟离子浓度增大到0.5%时,两种试件极化曲线均上移,自腐蚀电流密度增大,极化电阻减小（P 〈0.05）,试件表面均出现明显腐蚀;当加入酸之后（pH=5）,腐蚀更加明显。提示低浓度氟不会影响3M镍钛弓丝的耐腐蚀性,但会降低Damon铜镍钛弓丝的耐腐蚀性;高浓度氟和酸均会降低他们的耐腐蚀性,Damon铜镍钛弓丝的耐腐蚀性不及3M镍钛弓丝。     

四种正畸矫治弓丝的细胞毒性研究

目的评价四种临床常用正畸矫治弓丝经人工唾液浸泡腐蚀后的细胞毒性。方法选择正畸常用两种超弹性镍钛矫治弓丝和两种不锈钢矫治弓丝(A组:速航国产超弹性镍钛矫治弓丝;B组:Smart国产超弹性镍钛矫治弓丝;C组:PLASDENT国产不锈钢矫治弓丝;D组:ORMAER国产不锈钢矫治弓丝),在弱酸性(pH=6.0)人工唾液中浸泡4周后,取出试件制备浓度为20%、50%、100%的浸提液。使用不同浓度浸提液培养L-929细胞24 h、48 h后,分别使用SEM及MTT实验,初步评价四种矫治弓丝的细胞毒性。结果相同培养时间下,随浸提液浓度的增加,细胞相对增殖率减小,细胞毒性相对增加(P<0.05);相同浸提液浓度下,随培养时间的延长,细胞相对增殖率减小,细胞毒性相对增加(P<0.05)。100%浸提液浓度培养24 h后,四组浸提液均未对L-929细胞产生细胞毒性,培养48 h后,A、B、D三组浸提液对L-929细胞产生了轻微的细胞毒性,细胞毒性为1级,C组浸提液未对L-929细胞产生细胞毒性。结论经唾液浸泡腐蚀后的矫治弓丝,可能会引起轻微的细胞毒性,其结果应引起临床医生的重视。     

不锈钢丝与镍钛丝的临床应用比较

近年来，标准方丝弓矫正技术在正畸临床上广泛应用。作者通过对临床５７例牙列拥挤病例分别采用不锈多圆线和镍钛丝矫正后，发现两种弓丝在正畸的不同阶段效果不同。     

两种类型正畸弓丝固定外伤前牙的临床观察

目的探讨应用不同类型正畸弓丝固定外伤前牙的临床效果及操作时间。方法采用正畸固定技术分别应用镍钛圆丝与不锈钢方丝对外伤前牙进行固定，比较其疗效，操作时间。结果两种类型正畸弓丝固定外伤前牙均取得良好的效果，治疗结果无明显差异，但镍钛丝组的操作时间短于不锈钢方丝组。结论应用两种类型正畸弓丝采用正畸技术固定外伤前牙均可取得良好的治疗效果，但两种弓丝具有不同的特性，临床医师可根据病人情沈选择应用。     

上前牙严重舌倾的澳丝与镍钛丝矫正比较

目的：了解使用垂直曲的澳丝与镍钛丝在矫正上前牙严重舌倾的区别。方法：对27例上前牙严重舌倾的患者分别使用垂直曲的澳丝与镍钛丝矫正并对比矫正时间的长短。结果：使用垂直曲的澳丝矫正效率更高。结论：使用垂直曲的澳丝是矫正上前牙舌倾的有效方法之一。     

The corrosion resistance,cytotoxicity, and antibacterial properties of lysozyme coatings on orthodontic composite arch wires

Objective: The corrosion resistance of new orthodontic composite arch wires (CAWs), which have excellent mechanical properties in a simulated oral environment, must be improved. This study explored the susceptibility to corrosion, in vitro cytotoxicity, and antibacterial properties of lysozyme-coated CAWs. Methods: Lysozyme coating of laser-welded CAW surfaces was prepared by liquid phase deposition. Four groups of CAW specimens were prepared: uncoated CAWs and CAWs coated with 20, 40, and 60 g L⁻¹ lysozyme. The surface morphology of the lysozyme coatings was characterized by atomic force microscopy. The samples were immersed in artificial saliva (AS) for 2 weeks, and corrosion morphology was then observed by scanning electron microscopy. Corrosion behavior was characterized according to weight loss and electrochemical properties. The cytotoxicity and antibacterial properties of lysozyme-coated CAWs were assessed by cell counting kit-8 assay and a live/dead bacterial test, respectively. Results: Surfaces in the three lysozyme coating groups exhibited film-like deposition, the thickness of which increased with the lysozyme concentration. Surface pitting and copper ion precipitation decreased with increasing lysozyme concentration in coatings. The corrosion tendency declined as the corrosion and pitting potentials decreased. The corrosion morphology and electrochemical parameters together indicated that lysozyme coatings increased corrosion resistance. The coatings also reduced cytotoxicity to L-929 cells and increased anti-Staphylococcus aureus ability. Conclusions: Lysozyme coating of CAW surfaces by liquid phase deposition improved the corrosion resistance of CAWs. The protective coatings improved biocompatibility and endowed the CAW surfaces with certain degrees of anti-Staphylococcus aureus activity. Different lysozyme concentrations had different protective effects, with 40 g L⁻¹ maybe being the ideal lysozyme concentration for CAW coatings.

The corrosion resistance of new orthodontic composite arch wires (CAWs), which have excellent mechanical properties in a simulated oral environment, must be improved.     

In vitro study of GDNF release from biodegradable PLGA microspheres.

Glial cell line-derived neurotrophic factor (GDNF) is a protein with potent trophic actions on dopaminergic neurons, which is under investigation as a therapeutic agent for the treatment of neurodegenerative disorders, including Parkinson's disease. The aim of this work was to develop GDNF-loaded microspheres, which could be implanted by stereotaxy in the brain and could offer an alternative strategy in the treatment of Parkinson's disease. A w/o/w extraction-evaporation technique was chosen to prepare protein-loaded microspheres. An in vitro release study of the protein was required to assess the retention of integrity and the performance of the microsphere formulation with regard to sustained release. In order to assess the in vitro release profile of the GDNF-loaded microspheres, a preliminary study was performed to select an appropriate buffer for GDNF stabilization, using experimental designs. GDNF was measured by both enzyme-linked immunosorbant assay (ELISA) and radioactivity using (125)I-GDNF. The GDNF-loaded microsphere release profile was assessed in a low continuous flow system, and showed a sustained release over 56 days of biologically active GDNF at clinically relevant doses.     

In vitro release of nonoxynol-9 from silicone matrix intravaginal rings.

The controlled-release characteristics of matrix silicone intravaginal rings loaded with between 100 and 971 mg of nonoxynol-9 have been investigated with a view to developing a ring that may offer a new female-controlled method for the prevention of transmission of sexually transmitted diseases, particularly HIV. Intravaginal rings containing 253, 487 and 971 mg of nonoxynol-9 provided a daily release of 2 mg or more over the 8-day release period, the minimal amount of nonoxynol-9 considered to provide an effective vaginal concentration for the prevention of HIV. Furthermore, the maximum daily release of N9 was about 6 mg, an amount significantly smaller than that observed for other nonoxynol-9 products whose large daily doses may in fact increase the occurrence of HIV by causing epithelial damage to the vaginal tissue. The release mechanism of the liquid nonoxynol-9 from the intravaginal rings has also been investigated and compared to models describing the release of solid drugs from the rings. It has been demonstrated through release studies and surface microscopy that a drug depletion zone is not established in such liquid-loaded intravaginal ring systems, with implications for the release kinetics.     

In vitro production of new types of hemophilus influenzae

Two new types of Hemophilus influenzae, Sab and Sad have been produced in vitro. Each exhibits the presence of the type specific polysaccharides of 2 types of E. influenzae within the same cell. In Sab the polysaccharides of types a and b have been demonstrated and in Sad those which characterize types a and d. The Sab and Sad traits are inherited. Sab was produced by the action of DNA-containing extract isolated from type a on either type b cells or Rb cells (non-encapsulated non-type-specific cells derived from type b). Sad cells were formed as a result of the action of the DNA-containing extract isolated from type d on cells intermediate between Rab and Sab cells. DNA-containing extracts isolated from Sab cells have induced the Sab trait in Rd cells with predictable regularity. Evidence has been presented that the hereditary determinant of Sab cells is a new genetic substance with new functions. Therefore, the interaction of the DNA-containing substance from cells of one genetic type with living cells of a genetically different type has produced what appears to be a new individual which differs from each of the cells contributing the differing genetic traits but has at least one trait in common with each. Sab cells derived presumably from a single cell show the appearance of type b cells sometime during the first 7 generations.     

In vivo release of bupivacaine from subcutaneously administered oily solution. Comparison with in vitro release.

A non-randomized cross-over study was performed with bupivacaine HCl (5 mg x ml(-1)) aqueous solution and bupivacaine free base (4.44 mg x ml(-1)) in Viscoleo/castor oil 2:1 (v/v) administered s.c. to male Wistar rats. Plasma levels were analyzed by LC-MS. Plasma profiles obtained after administration of oily solution showed a prolonged bupivacaine release with lower peak plasma levels as compared to administration of an aqueous formulation applied in the same compartment. t(1/2), t(max), C(max) and AUC(0-infinity) for the aqueous solution were 63+/-8 min, 19+/-16 min, 194+/-46 ng x ml(-1) and 25,000+/-3000 ng min x ml(-1), respectively, while the corresponding data for the oil solution were 368+/-89 min, 334+/-186 min, 36+/-25 ng x ml(-1) and 25,000+/-6000 ng x min x ml(-1). The present data indicate the potential of designing an oil formulation of bupivacaine with a prolonged local analgetic effect exhibiting a minimum of systemic toxicity. In vivo release of bupivacaine from the oil solution was evaluated by a numerical deconvolution method. In vivo release kinetics was found to be first-order and corresponded well with in vitro release kinetics found using a rotating dialysis cell. This led to establishment of an in vitro/in vivo correlation for this particular formulation.     

In vitro and in vivo release of ciprofloxacin from osteoconductive bone defect filler

OBJECTIVES: Impregnation of antimicrobial agents within biodegradable carriers with osteoconductive properties could provide the means for one-stage surgical treatment of osteomyelitis. In this study, the in vitro and in vivo antibiotic release from this type of bone defect filler was characterized. METHODS: Cylindrical pellets (2.5 x 1.5 mm) were manufactured from bioabsorbable poly(L-lactide-co-glycolide) (PLGA) matrix, ciprofloxacin [8.3 +/- 0.1% (w/w)] and osteoconductive bioactive glass microspheres (90-125 microm) [27 +/- 2% (w/w)]. In vitro studies were carried out to delineate the release profile of the antibiotic. The antimicrobial activity of the release antibiotic was verified with MIC testing. In a time-sequence study in the rabbit, pellets were surgically implanted in the proximal tibia and the antibiotic concentrations achieved in bone were measured at 1, 2, 3, 4, 5 and 6 months. RESULTS: In vitro elution studies showed sustained release of ciprofloxacin at a therapeutic level (>2 microg/mL) over a time period of 4 months. The released ciprofloxacin had maintained its antimicrobial capacity against five standard ATCC strains. In vivo, the delivery system produced high local bone concentrations (247.9 +/- 91.0 mug/g of bone) for a time period of 3 months with no significant systemic exposure. Histomorphometry and micro-CT imaging confirmed new bone formation around the pellets within 3 months as a sign of an independent osteoconductive property of the composite. CONCLUSIONS: The tested composite seems to be a promising option for local therapy of surgically treated bone infections. The main advantages are the antibiotic release for a definite time period with therapeutic concentrations, which may minimize slow residual release at suboptimal concentrations.     

In vitro release of fentanyl from transdermal patches in gastric and intestinal fluid

Context. Fentanyl patches are intended for transdermal use to treat pain. However, these patches have been abused by ingestion, offering a unique mode of drug delivery with unknown drug release characteristics. Objectives. In vitro fentanyl release from patches in simulated gastric and intestinal fluid was evaluated. Materials and methods. Ten 75 mcg/hr fentanyl transdermal patches (Mylan Pharmaceuticals Inc., Morgantown, WV), simulated gastric fluid without enzymes, and USP simulated intestinal fluid (Ricca Chemical Company, Arlington, TX) were obtained. Each fentanyl patch was placed into either 100 mL of simulated gastric fluid or 100 mL of simulated intestinal fluid. Flasks were agitated at 24 rpm while incubated at 36.8°C. Fluid was sampled at time zero and 5, 15, 30, 60, 120, and 180 min after submersion. Fentanyl was assayed using ultra performance liquid chromatography coupled with tandem mass spectrometry (AIT Laboratories, Indianapolis, IN). Results. An average of 239 mcg and 1,962 mcg of fentanyl was released into gastric fluid and 338 mcg and 3,139 mcg into intestinal fluid in 5 min and 3 h, respectively. An average of 26% and 41% of 7.65 mg of fentanyl contained within the 75 mcg/hr patch was released into gastric and intestinal fluid in 3 h, respectively (p = 0.169, Student's t-test). Discussion. Our results demonstrate fentanyl release within 5 min of submersion. Conclusion. These results help support the potential rapid onset of clinical compromise reported and are relevant to the design of future pharmacokinetic studies of fentanyl release from transdermal patches.