骨内种植体覆盖螺丝的缝隙腐蚀研究

钛种植体在口腔中腐蚀现象已被学者研究发现并引起重视。骨内是否存在纯钛种植体缝隙腐蚀？本文对此进行了动物实验研究。扫描电镜结果友现：金属腐蚀发生与存在介质环境密切相关；在骨介质环境中2、4、6、8、12周五个时间段内纯钛种植体在骨内未发现明显覆盖螺丝的缝隙腐蚀。     

多孔中空柱状钛种植体复合牛骨形成蛋白的实验研究Ⅰ生物力学测试

目的 :通过抗拔力和抗扭转力测试 ,评价种植体的生物力学性能。方法 :将多孔中空柱状钛种植体与牛骨形成蛋白复合 (B组 )植入狗的股骨中 ,以实心柱状种植体 (A组 )及单纯多孔中空柱状钛种植体(C组)为对照 ,分别于植入后2 ,4 ,8 ,16 ,24周处死动物 ,进行抗拉拔力及抗扭转力测试。结果 :在各时间点 ,B组的剪切强度都明显高于A组 ,除植入后24周 ,B、C两组的剪切强度无明显差异外 ,其余时间点B组都明显高于C组;扭矩值随时间增大 ,各时间点上 ,B组均大于A、C两组 ,C组大于A组。结论 :骨形成蛋白与中空多孔种植体复合 ,可提高种植体的力学性能 ,缩短种植周期 ,有重要的临床应用价值。     

钛锆合金种植体的研究进展

钛锆合金（TiZr）作为一种新型合金材料,在口腔种植领域具有广泛的应用前景。由于其弥补了传统纯钛种植体机械强度方面的不足,且抗腐蚀性和生物相容性佳,目前钛锆合金窄直径种植体已初步应用于临床。本文就钛锆合金种植体的机械力学特性、抗腐蚀性、表面性能、生物相容性及临床应用的预后作一综述。     

补肾方剂对骨质疏松大鼠纯钛种植体骨结合影响的骨计量学研究

目的:观察补肾方剂对骨质疏松大鼠纯钛种植体骨结合的影响,探讨补肾方剂促进纯钛种植体骨结合的机制。方法:选用纯种8月龄雌性SD大鼠54只,随机分为3组。A组:假手术组,B组:卵巢切除组,C组:卵巢切除加中药治疗组。在3组大鼠胫骨近中干骺端分别植入纯钛光滑柱状种植体。C组大鼠用补肾方剂灌胃。种植术后1、2、3个月,取出带种植体的胫骨,制作HE染色的组织切片,骨计量学观察。结果:C组的骨小梁宽度、结合骨板宽度、松质骨区骨量、成骨细胞数均明显大于B组(P<0.01)。结论:补肾方剂可以使骨质疏松大鼠种植体周围的成骨细胞数增加,松质骨区骨量明显增加,促进骨改建,提高骨结合的质量。     

国产微型钛钉正畸支抗即刻负载稳定性的实验研究

目的:评估国产微型钛钉种植支抗即刻负载稳定性。方法:随机选择犬下颌骨的一侧为实验组即加力组,另一侧为对照组即不加力组,植入国产微型钛钉各两颗。实验组钛钉间施力200克。三个月后处死动物,分别测量实验组、对照组钛钉间的位移变化及种植体—骨界面剪切力。结果:实验组钛钉间位移平均减少0.47mm;对照组几无变化;实验组种植体-骨界面剪切力明显大于对照组,平均为367.42牛顿。结论:国产微型钛钉作为种植支抗可满足临床要求。     

钛种植体表面改性的现状、问题与发展趋势

钛在生理环境中具有良好的化学稳定性、良好的机械力学性能及良好的生物相容性,是口腔种植的首选材料。理想的种植材料应能在植入后刺激新骨的形成并与骨形成骨性结合,纯钛表面呈生物惰性,不能诱导新骨的形成。因此,植入后如何增强成骨诱导性,加速与骨的骨性结合是钛种植体表面改性的一个重要方向。另外,临床研究表明种植体周围感染是导致种植失败的一个重要因素,因此赋予钛种植体表面持续的抗菌性是钛种植体改性的另一重要方向。     

种植体材料钛与种植体上部结构合金问电偶腐蚀性能的研究

目的 评价TA2型商业纯钛分别与金合金、钴铬合金、钛合金及镍铬合金在体外的电偶腐蚀行为.方法 在人工唾液中体外模拟TA2型商业纯钛分别与金合金、钴铬合金、钛合金及镍铬合金接触时的回路,测量其15 h的混合电位和电偶电流值并描绘电流时间曲线.结果 四组合金接触8 h后电流达到稳定,稳定后电偶电流值排列顺序为Ti/Au相似文献   

种植体材料钛与种植体上部结构合金间电偶腐蚀性能的研究

目的评价TA2型商业纯钛分别与金合金、钴铬合金、钛合金及镍铬合金在体外的电偶腐蚀行为。方法在人工唾液中体外模拟TA2型商业纯钛分别与金合金、钴铬合金、钛合金及镍铬合金接触时的回路,测量其15 h的混合电位和电偶电流值并描绘电流时间曲线。结果四组合金接触8 h后电流达到稳定,稳定后电偶电流值排列顺序为Ti/Au相似文献   

3种义齿清洁剂对钴铬合金及纯钛耐腐蚀性的影响

目的:比较3种常用义齿清洁剂对铸造钴铬合金及纯钛耐腐蚀性的影响.方法:采用Tafel曲线电化学腐蚀测量法测出钴铬合金(CoCr)和纯钛(CP Ti)试件在不同义齿清洁剂中的自腐蚀电位(Ecorr),自腐蚀电流密度(Icorr),绘制出相应的极化曲线,应用扫描电子显微镜观察试件实验前后表面形貌的改变,并对实验结果进行双因素方差分析.结果:在不同义齿清洁剂中钴铬合金Ecorr大于纯钛,Icorr小于纯钛,差异有统计学意义(P＜0.05);钴铬合金在Protefix中的耐腐蚀性Ecorr最大,Icorr 最小,表面腐蚀坑较少;纯钛组在保丽净中Ecorr最大,Icorr较小,表面腐蚀坑较少.结论:在不同义齿清洁剂中钴铬合金耐腐蚀性优于纯钛;不同义齿清洁剂对钴铬合金和纯钛耐腐蚀性的影响有差异.     

钛种植体与冠修复金属电偶腐蚀电流的研究

目的 通过对HBIC型钛种植体与口腔科常用修复烤瓷合金在中性和酸性人工唾液中的电偶腐蚀的综合评价,筛选更适合种植体上部结构的冠修复材料.方法 选择HBIC型钛种植体(T-H)以及镍铬合金(Ni)、钴铬合金(Co)、金铂合金(Au)、铸造纯钛(Ti),每种金属制成直径4mm、高10mm的圆柱体电极各40个.采用电化学方法,在自行配制的pH =6.8、pH =5.6两种人工唾液中检测4种合金分别与T-H组成的电偶对的电偶电流密度(Id),并绘制出各自的电流时间曲线.结果 在中性人工唾液中四种电流密度依次为IdNi＞ IdCo＞IdTi＞IdAu,其中Ni组与Au组、Ti组间有统计学差异(P＜0.05),Co组与Ni组、Ti组、Au组,Ti组与Au组间无统计学差异(P＞0.05).在酸性人工唾液中四种电流密度依次为IdNi＞IdCo＞IdAu＞IdTi,其中Ni组显著大于Ti组、Co组、Au组,有统计学差异(P＜0.05),Ti组、Co组、Au组三组间无统计学差异(P＞0.05).扫描电镜观察,酸性环境中镍铬合金发生少量坑状腐蚀形貌,其余合金与中性环境相比无明显变化.结论 两种唾液中镍铬合金组电偶电流较大.酸性环境能增大电偶腐蚀,对镍铬合金影响较大,镍铬合金不适宜作为钛种植体上部冠修复材料.     

钛-75合金与纯钛犬股骨内长期种植后的组织学比较研究

目的 :为弥补纯钛在机械性能方面存在的缺陷 ,开发新的牙种植材料 ,我们选用机械性能优于纯钛的新型的钛合金材料 :钛 - 75 (钛铝钼锆TiAlMoZr)作为实验对象。方法 :以纯钛作对照 ,将两种材料种植于犬股骨中 ,分别经 3个月、6个月、12个月、2 4个月、36个月后取材 ,进行种植体、骨界面的X -线检查 ,不脱钙骨切片光镜观察和电镜等组织学观察。结果 :钛 - 75与骨组织结合紧密 ,无结缔组织介入 ,界面组织结构与纯钛比较无明显差异。结论 :提示钛 - 75具有与纯钛相近的组织相容性     

Implant abutment screw rotations and preloads for four different screw materials and surfaces.

STATEMENT OF PROBLEM: Chronic implant screw loosening remains a problem in restorative practices. Some implant manufacturers have introduced abutment screws with treated surfaces in an effort to increase preload and reduce potential loosening. Purpose. This study evaluated the materials and surfaces of 4 commercially available abutment screws on preload generation. MATERIAL AND METHODS: Twenty of each of the following abutment screws-Gold-Tite (Gt), TorqTite (Tt), gold alloy (Ga), and titanium alloy (Ta)-were divided into 2 groups. Measurements were recorded for each abutment screw on a mounted 3.75 x 18 mm external hex implant with a titanium abutment. Rotational angle measurements were conducted on the 4 abutment screws at 20 and 32 Ncm. Removal torque values were recorded and used to indirectly generate preload values. Random implant block specimens were sectioned and qualitatively evaluated with an SEM. RESULTS: At 20 and 32 Ncm, the largest rotational angles were recorded for the Tt groups: 21.2 +/- 3.1 degrees and 38.1 +/- 8.7 degrees, respectively. The greatest preload values at 20 and 32 Ncm were calculated for the Gt groups: 596.8 +/- 101.2 N and 1015.3 +/- 191.2 N, respectively. SEM analysis of the 4 implant block specimens revealed mating thread contacts located in the middle portion of the superior surface of the abutment screw thread. The greatest number of mating thread contacts were seen in the Gt implant block specimen (14 of 20 possible thread contacts). CONCLUSION: The Gt and Tt abutment screws with enhanced surfaces that help reduce the coefficient of friction produced greater rotational angles and preload values than the conventional gold alloy and titanium alloy screws.     

Finite element analysis to determine implant preload

STATEMENT OF PROBLEM: The nature of the forces used to clamp implant components together, and how they are generated and sustained, is lacking in the literature. PURPOSE: This study examined the dynamic nature of developing the preload in an implant complex using finite element analysis. METHODS: The implant complex was modeled in accordance with the geometric designs for the Nobel Biocare implant systems. A thread helix design for the abutment screw and implant screw bore was modeled to create the geometric design for these units of the implant systems. Using the software programs HyperWorks and LS3D-Dyna, 2 3-dimensional finite element models of (1) a Branemark System 3.75 x 10-mm titanium Mark III implant, a CeraOne titanium abutment, a Unigrip gold alloy abutment screw, and (2) a Replace Select System 4.30 x 10-mm titanium implant, a Straight Esthetic titanium abutment, and a TorqTite titanium abutment screw were created. Modeling the threads to the machining specifications permitted simulation of screw tightening. The abutment screws were subjected to a tightening torque in increments of 1 Ncm from 0 to 64 Ncm using ABAQUS software. Using these models, the effect of the coefficient of friction on the development of preload amount in the implant complex during and after abutment screw tightening was determined. In the first experiment, the coefficient of friction was set to 0.20 between the titanium bearing surface of the abutments and the implant bearing surfaces, and 0.26 between the gold abutment screw and the titanium implant screw bore. In the second experiment, the coefficient of friction was varied; the titanium implant and titanium abutment bearing surfaces were set to a coefficient of friction of 0.20, whereas the Mark III gold and the Replace Select titanium abutment screws and their respective titanium screw bores in the implants were set to 0.12. The preload amount (N) was determined from the finite element analysis. RESULTS: The stress distribution pattern clearly demonstrated a transfer of preload force from the screw to the implant during tightening. A preload of 75% of the yield strength of the abutment screw was not established using the recommended tightening torques. CONCLUSION: Using finite element analysis, a torque of 32 Ncm applied to the abutment screws in the implant assemblies studied in the presence of a coefficient of friction of 0.26 resulted in a lower than optimum preload for the abutment screws. To reach the desired preload of 75% of the yield strength, using a torque of 32 Ncm applied to the abutment screws in the implant assemblies studied, the coefficient of friction between the implant components should be 0.12.     

Oral mucosa tissue response to titanium cover screws

Background: Titanium is the most widely used metal in dental implantology. The release of particles from metal structures into the biologic milieu may be the result of electrochemical processes (corrosion) and/or mechanical disruption during insertion, abutment connection, or removal of failing implants. The aim of the present study is to evaluate tissue response of human oral mucosa adjacent to titanium cover screws. Methods: One hundred fifty‐three biopsies of the supra‐implant oral mucosa adjacent to the cover screw of submerged dental implants were analyzed. Histologic studies were performed to analyze epithelial and connective tissue as well as the presence of metal particles, which were identified using microchemical analysis. Langerhans cells, macrophages, and T lymphocytes were studied using immunohistochemical techniques. The surface of the cover screws was evaluated by scanning electron microscopy (SEM). Results: Forty‐one percent of mucosa biopsies exhibited metal particles in different layers of the section thickness. Particle number and size varied greatly among specimens. Immunohistochemical study confirmed the presence of macrophages and T lymphocytes associated with the metal particles. Microchemical analysis revealed the presence of titanium in the particles. On SEM analysis, the surface of the screws exhibited depressions and irregularities. Conclusions: The biologic effects seen in the mucosa in contact with the cover screws might be associated with the presence of titanium or other elements, such as aluminum or vanadium. The potential long‐term biologic effects of particles on soft tissues adjacent to metallic devices should be further investigated because these effects might affect the clinical outcome of the implant.     

微弧氧化钛基体含Si、Ca涂层的表征及植入兔胫骨影像学和力学性能研究

目的:观察及评价含Si、Ca涂层的微弧氧化钛基体的涂层表征及其骨结合性。方法:在纯钛基体上通过微弧氧化(microarc arc oxidation MAO)的方法制备含Si、Ca元素的涂层并对其进行表征。根据国家标准将该材料植入兔胫骨,在植入后4、8、12周进行X射线及力学性能评价。结果:涂层表面成功的引入了Si、Ca元素。X射线显示材料植入后无炎症效果,力学性能测试表明该材料与骨的结合力高于纯钛种植体。结论:含Si、Ca涂层的微弧氧化钛种植体与骨结合性能良好。     

An in vitro load evaluation of a conical implant system with 2 abutment designs and 3 different retaining-screw alloys

PURPOSE: The aim of this in vitro study was to evaluate the load resistance in a conical implant system by comparing combinations of 2 different abutment head angles and 3 different retaining screw materials. MATERIALS AND METHODS: The retaining screw materials (titanium alloy, gold alloy, and commercially pure titanium) were tested with abutment-head angles of 20 degrees and 45 degrees. Six groups of 10 specimens each were prepared. An oblique (30-degree) compression test was performed in a Lloyd LRX universal testing machine with the abutment attached to a superstructure with a retaining screw. All specimens were loaded until fracture or permanent deformation occurred. The results were evaluated statistically with Wilcoxon signed rank test for variance distribution (P < .05 considered significant). RESULTS: There were statistically significant differences in load resistance between 20-degree and 45-degree abutments. The titanium screws (titanium alloy and commercially pure) in the 45-degree abutment group had almost equal mean values, while the gold alloy had a significantly lower value. In the 20-degree abutment group, significantly higher values were found with commercially pure titanium compared to titanium alloy and gold alloy, but the difference between the values for the gold and titanium alloys was not significant. DISCUSSION: The angulation of the abutment head played the most significant role in determining the amount of load withstood, but the material used for the screw was also relevant. CONCLUSION: A 45-degree abutment can be combined with a retaining screw of any of these materials to create a functional implant system. The test also substantiated that, irrespective of the retaining-screw material, a 20-degree abutment could resist loading forces of at least 900 N.     

增材制造Ti-6Al-4V钛合金种植体骨结合的动物实验研究

目的探讨增材制造Ti-6Al-4V（TC4）钛合金种植体动物体内的骨结合和成骨效果,为进一步临床应用提供实验依据。 方法选择健康雄性新西兰兔42只,以兔双侧后腿股骨髁部为种植体植入区,将实验兔先分为2周（A组）、8周（B组）2个大组,每组21只;每大组中再分为3个亚组,分别为A1组、A2组、A3组和B1组、B2组、B3组,每小组7只。A1组和B1组实验兔双侧后腿股骨髁部分别植入原始表面和表面改性TC4钛合金种植体各1枚;A2组和B2组实验兔植入原始表面TC4钛合金种植体和钛骨种植体各1枚;A3组和B3组实验兔植入表面改性TC4钛合金种植体和钛骨种植体各1枚;使2周、8周均含有3种种植体各14枚。术后2、8周观察并比较分析3种种植体的植入成功率和骨结合情况,观察指标为：骨体积分数（BV/TV）、骨小梁面积密度（BS/BV）、骨小梁厚度（Tb.Th）、骨小梁数量（Tb.N）和骨小梁间隔（Tb.Sp）。对各组不同时段种植体骨界面骨密度指标,使用SPSS 21.0软件包对数据进行双因素方差分析,验证不同表面、不同时间对种植体骨结合水平的影响,并采用Tukey′s多重比较检验分析组间统计学差异。 结果3种种植体不脱钙组织切片、骨块微CT扫描及光学显微镜观察显示,随着植入后的时间进展,3种种植体表面骨组织的量逐渐增多,分布逐渐变密。2周时,表面改性TC4钛合金种植体组的BV/TV、Tb.N显著高于原始表面和钛骨组,差异有统计学意义（P<0.05）;Tb.Th显著高于钛骨组（P<0.05）;BS/BV、Tb.Sp显著低于钛骨组,差异有统计学意义（P<0.05）。8周时,3种种植体的BV/TV、BS/BV、Tb.Th、Tb.N和Tb.Sp差异均无统计学意义（P>0.05）。 结论表面改性TC4钛合金种植体2周时即能形成更多的骨组织,骨小梁的分布更密集,骨结合能力更强,有望成为口腔种植体的优选材料。     

不同pH值与氟离子浓度对口腔常用金属修复材料电化学腐蚀的影响

目的 研究不同pH值与不同浓度氟离子(F-)对HBIC种植体和常用的四种冠修复金属材料在人工唾液中电化学腐蚀的影响.方法 将5种口腔常用金属,金合金(Au)、镍铬合金(NiCr)、钴铬合金(CoCr)、铸造纯钛(Ti)、HBIC种植钛材(H-Ti)分别置于不同pH值与含和不含F-的人工唾液中,采用动电位极化曲线法测得其自腐蚀电位和自腐蚀电流密度,分析材料的耐腐蚀性.结果 金合金、钴铬合金、镍铬合金的腐蚀电流密度随着H+的浓度增加而变大,差异有统计学意义(P<0.05),铸造纯钛及种植钛材在酸性含氟人工唾液中的腐蚀电流密度和自腐蚀电位变化明显,差异有统计学意义(P<0.05),F-对金合金的耐腐蚀性影响不明显.结论 pH的改变以及含氟环境会加剧种植体及其常用上部冠修复材料的电化学腐蚀性,金合金与纯钛的耐腐蚀性能较强.     

Aay4对钛及钛75合金表面失泽腐蚀的研究

目的　研究放线共生放线杆菌血清b型 (Aay4)对钛及钛 75合金种植体表面的失泽腐蚀。方法　将纯钛、钛 75合金机械加工成 10mm× 10mm× 1mm的板片 ,数量分别为 30片和 6 0片 ,取钛 75合金试件 30片与纯钛试件分别进行化学钝化。将钝化纯钛组 30片随机分成空白组、培养基组和实验组 ,每组各 10片。在厌氧环境中将Aay4接种到改良GAM培养基上 ,将试件贴附于表面 ,每周转换传递 1次 ,共 10周。用 0 0 5 %戊二醛灭菌 ,清洗 ,2周后进行色度计观察。结果　肉眼观察见纯钛、钛 75合金 (钝化与非钝化 )的实验组试件表面颜色均由银灰色变成黄色。 3种试件的空白对照与培养基对照组的L 、a 、b 值无显著变化 ;而实验组分别与空白对照组、培养基对照组比较 ,其L 、a 、b 值的差异均有显著性 (P <0 0 5 )。结论　Aay4对钛及钛 75合金 (钝化和非钝化 )均发生肉眼可见的表面失泽。色度计分析表明 ,3种类型的种植体试件表面颜色由绿黄区域落到了红黄区域     

Smoking and complications of endosseous dental implants

BACKGROUND: The purpose of this study was to compare the incidence of the complications and survival rate related to dental implants among smokers and non-smokers, and to evaluate the influence of smoking by analyzing data of 959 implants placed in 261 patients during the years 1995 to 1998. METHODS: Patients were divided into 3 groups: non-smokers, mild smokers (up to 10 cigarettes per day) and heavy smokers (more than 10 cigarettes per day); smokers were divided into 2 subgroups according to duration of smoking (less or more than 10 years). Complications included minor (spontaneous implant exposure), major (spontaneous implant exposure requiring surgical intervention), and implant failure. The influence of smoking was analyzed for the type of implant cover screw and immediate versus late implantation. RESULTS: The overall failure rate was 2% for non-smokers and 4% for all smokers. Minor and major complications were found in higher percentages (46%) in the smoking groups than in the non-smoking group (31%). A significantly higher incidence of complications was found among smokers who received dental implants with high cover screws (63%) compared to those who received dental implants with flat cover screws (27%). CONCLUSIONS: This study establishes a relationship between implant complications and smoking, implant type (external or internal hex), and time of implantation as significant factors. A higher incidence of complications was found in the smoking group, especially in implants that had a high cover screw. Most complications will not lead to failures. Immediate implants failed less frequently than non-immediate implants. Limiting or reducing smoking habits will decrease complications of endosseous dental implants.