不同陶瓷托槽与金属弓丝间摩擦力的研究

目的 研究不同类型陶瓷托槽与金属弓丝间的摩擦力,为临床应用及研制摩擦性能优良的陶瓷托槽提供参考.方法 选取正畸临床上常用的三种陶瓷托槽作为研究对象,一种金属托槽作为对照组.利用MTSTytron250微力实验机检测托槽与三种金属弓丝在不锈钢丝结扎下的最大静摩擦力和平均动摩擦力.结果 金属托槽与不锈钢圆丝间的最大静摩...     

国产陶瓷托槽与金属弓丝间滑动摩擦力的研究

目的检测体外条件下国产多晶体氧化铝陶瓷托槽与金属弓丝在不同夹角时的滑动摩擦力,为其改良提供参考信息。方法利用摩擦力测量装置检测弓丝与槽沟的夹角分别为0°和5°时,国产陶瓷托槽分别与0.016、0.016×0.022、0.019×0.025英寸不锈钢丝和镍钛丝间的滑动摩擦力,每组样本量为10。对照组为临床常用多晶体氧化铝陶瓷托槽(Crystaline IV)。结果国产陶瓷托槽的摩擦力显著高于Crystaline IV,且除0°夹角、0.016英寸不锈钢圆丝和镍钛圆丝及0.016×0.022英寸不锈钢方丝外,其余情况下两种陶瓷托槽间摩擦力的差异有显著性(P0.01)。镍钛丝产生的摩擦力高于不锈钢丝,弓丝尺寸增加,摩擦力增加,弓丝与槽沟夹角为5°产生的摩擦力高于0°。结论国产陶瓷托槽的摩擦力性能不能满足临床使用的要求,需要进一步改良。     

陶瓷托槽槽沟形貌及滑动摩擦现象的观察

目的对四种托槽和两种弓丝滑动前后进行外貌和槽沟微观形貌的分析,探讨影响托槽与弓丝间摩擦力大小的因素。方法对四种托槽用立体显微镜对外观形貌及其与两种弓丝滑动前后扫描电镜的微观形貌进行观察,用微硬度测量仪测量四种托槽槽沟、托槽体部位的硬度。结果四种托槽形貌及滑动前后槽沟部位的微观形貌不同,硬度也有差异,硬度由小到大分别为A托槽的金属槽沟部位（F）213．72±57．33HV,D托槽305．76±46．65HV,B托槽1087．12±139．86HV,A托槽体部1111．26±182．52HV,C托槽1309．81±225．56HV。结论硬度和表面粗糙度是影响托槽与弓丝间摩擦力的因素。陶瓷托槽硬度大,表面粗糙,与金属弓丝间的摩擦力大。     

纳米TiO2陶瓷涂层托槽耐磨性研究

目的：对自行研制的纳米TiO2陶瓷涂层直丝托槽耐磨性进行测试,并与国产普通金属直丝托槽进行比较。方法：选取纳米TiO2陶瓷涂层直丝托槽与国产普通金属直丝托槽各5付,测试比较弓丝拉伸前后托槽表面光洁度、托槽-弓丝摩擦力,评估托槽耐磨性。结果：纳米TiO2陶瓷涂层直丝托槽较国产普通金属直丝托槽耐磨性好,弓丝拉伸前后托槽表面光洁度、托槽-弓丝摩擦力无明显改变。结论：纳米TiO2陶瓷涂层直丝托槽具有良好耐磨性,可以满足口腔正畸临床需要。     

纳米陶瓷涂层托槽的表征及力学性能研究

目的：对自行开发研制的纳米TiO2陶瓷涂层直丝弓托槽的表面性能及力学性能进行初步测试，并与国产普通金属直丝弓托槽进行比较。方法：使用划痕实验法测试纳米陶瓷涂层材料与基体材料的结合强度；选取纳米TiO2陶瓷涂层直丝弓托槽与国产普通金属直丝弓托槽各3付，测试比较托槽槽沟表面光洁度、托槽-弓丝摩擦力。结果：纳米TiO2陶瓷薄膜涂层与托槽基底具有很强的结合能力。纳米陶瓷涂层直丝弓托槽与国产普通金属直丝弓托槽相比，具有良好的表面光沽度，且托槽。弓丝摩擦力明显减小。结论：纳米陶瓷涂层直丝弓托槽具有良好的表面性能及力学性能，可以满足口腔正畸临床的需要。     

陶瓷托槽与金属弓丝第二序列成角状态下摩擦性能的研究

目的研究陶瓷托槽与金属弓丝在第二序列成角状态下的摩擦力,探讨影响托槽弓丝间摩擦力的因素。方法进行托槽外观形貌的测量与观察,计算托槽与弓丝第二序列成角下的临界角,并设计带可调节罗盘的载物台,用MTS Tytron250微力试验机体外测试三种陶瓷托槽（A、B、C）和一种金属托槽（D）与0.016英寸不锈钢圆丝（SS）在第二序列成角分别为0度、2度、5度、8度时的最大静摩擦力和滑动摩擦力。结果与0.016英寸SS的摩擦力总体表现出B托槽〉C托槽〉A托槽〉D托槽的趋势,在四种成角状态下的最大静摩擦力随角度加大而增大,总体表现为0度到2度的摩擦力增加没有显著性,增大夹角后摩擦力增加量不同托槽间有差异：A托槽与弓丝在2度到5度成角状态下的摩擦力增加没有显著性,而5度到8度的摩擦力有显著增加;B托槽在2度到5度摩擦力有显著增加,而5度到8度摩擦力增加不显著;虽然2度到5度摩擦力增大没有显著性,但8度与0度状态下相比,C托槽与弓丝间的摩擦力有显著增加;D托槽在2度、5度、8度时摩擦力间差异无显著性。结论选用带金属槽沟的陶瓷托槽,增加陶瓷托槽边缘的圆钝程度等能减缓牙齿移动中托槽-弓丝成角引起的滑动阻力增加;使用传统陶瓷托槽要注意充分排齐。     

国产直丝陶瓷托槽摩擦力性能的研究

目的研究国产直丝陶瓷托槽的摩擦力性能。方法利用MTS Tytron250微力试验机测定我院与清华大学联合研制开发的下颌尖牙位直丝陶瓷托槽与0．016英寸不锈钢圆丝、0．016×0．022英寸不锈钢方丝、0．016英寸镍钛丝在不锈钢丝结扎方式下的摩擦力,并以一种进口陶瓷托槽作为对照组。结果国产直丝陶瓷托槽的最大静摩擦力与对照组陶瓷托槽相比差异无显著统计学意义,平均动摩擦力比对照组陶瓷托槽显著降低。结论国产直丝陶瓷托槽的摩擦性能可以满足临床需要。     

自制美学涂层弓丝摩擦力的实验研究

目的：对自制美学涂层弓丝的摩擦力进行测试,并与普通不锈钢弓丝比较。方法：在干燥条件下,模拟临床牙齿移动,分别测定0．018″美学涂层不锈钢圆丝和0．018″普通不锈钢圆丝与3种美学托槽（陶瓷托槽、树脂托槽、带金属槽沟的陶瓷托槽）组合的摩擦力并进行比较。同时比较与美学涂层弓丝组合时,3种托槽之间的摩擦力大小。结果：在与3种美学托槽组合时,美学涂层不锈钢圆丝与普通不锈钢圆丝的摩擦力虽有不同,但无显著性差异。3种美学托槽与美学涂层弓丝组合时,陶瓷托槽的摩擦力明显大于树脂托槽和带金属槽沟的陶瓷托槽,而后两者之间无统计学差异。结论：此种美学涂层弓丝符合口腔正畸临床使用要求。     

两种不同弹力结扎对滑动摩擦力大小影响的体外实验研究

目的通过体外实验研究MBT金属托槽应用两种不同的弹力结扎时滑动摩擦力的大小。方法选择3M公司的上颌第二双尖牙MBTmini金属托槽和0．46×0．64mm（0．018×0．025英寸）不锈钢弓丝,分别采用意大利Leone公司生产的Slide^TM结扎圈和美国TP公司生产的传统弹力圈结扎,应用自行设计开发的摩擦力测试仪,弓丝沿托槽低速滑动,并在滑动中保持特定的托槽——弓丝成角,共计12个角度。测量每一种弓丝、不同角度下的滑动摩擦力大小。结果在被动状态下两种结扎方式的滑动摩擦力均基本保持不变,Slide^TM结扎的摩擦力非常小,几乎可以忽略不计;在主动状态下,摩擦力随角度增加而增大,slide^TM结扎产生的滑动摩擦力仍明显小于传统弹力结扎。结论应用LeoneSlide^TM结扎圈,可以显著减小矫治器的滑动摩擦力。     

常用国产、进口正畸托槽的槽沟宽度精度及表面光洁度的比较

目的比较临床常用的国产金属直丝弓托槽和进口金属直丝弓托槽槽沟宽度及其精度、槽沟近远中截面光洁度和结扎翼光洁度。方法采用施奈德坐标测量仪对4种国产金属直丝弓托槽和4种进口金属直丝弓托槽放大30倍后进行测量。结果国产托槽和进口托槽槽沟的近、远中宽度均有良好的一致性,但国产托槽和进口托槽槽沟宽度普遍大于设计值;进口托槽槽沟近远中端截面的光洁度优于国产托槽,国产托槽结扎翼表面光洁度已达到进口托槽结扎翼表面光洁度水平。结论绝大部分国产和进口直丝弓金属托槽槽沟宽度较设计值大,个别品牌托槽槽沟宽度显著大于设计值。国产和进口金属托槽结扎翼表面均有较好的抛光度,但国产托槽槽沟内的抛光工艺尚待提高。     

2种不同粘接水门汀对树脂类冠修复材料和全瓷托槽剪切粘接力的影响

目的 评价两种不同粘接水门汀对树脂类冠修复材料和全瓷托槽剪切粘接力的影响。方法 选用2种水门汀Transbond XT和RelyX Ultimate,将上颌前磨牙全瓷托槽Inspire Ice与4种树脂类冠修复材料粘接。试件冷热循环5 000次后测量断裂载荷（N）,并观察破坏形态。结果 单因素方差分析结果F=4.52（P＜0.001）,显示粘接条件对陶瓷托槽和树脂类冠修复材料的剪切粘接力影响具有统计学意义。其中Lava Ultimate+Transbond XT组和Lava Ultimate+ RelyX Ultimate+托槽喷砂组分别为（325.10±135.54）N和（304.71±35.71）N,较其他组高,Lava Ultimate+ Transbond XT+托槽喷砂组最低,为（118.12±57.58）N。结论 树脂基陶瓷材料Lava Ultimate和全瓷托槽的剪切粘接力较暂时冠修复材料高。全瓷托槽未喷砂时,正畸全瓷托槽粘接水门汀Transbond XT和修复用水门汀RelyX Ultimate的粘接力未见明显区别,喷砂后全瓷托槽失去固位小球,RelyX Ultimate有更高的粘接力。     

Effect of bracket and wire composition on frictional forces

Previous work on friction has considered movement of single teeth along an archwire. The aim of this investigation was to consider friction in buccal segment attachments during overjet reduction involving sliding mechanics. A buccal segment model was constructed to compare friction in steel and ceramic brackets, using steel and nickel titanium wires of two sizes along with a new experimental polymeric wire. The results indicate that friction during overjet reduction is minimized by using larger dimension rectangular wires and by using steel rather than nickel titanium. Comparing steel with ceramic brackets in series, the latter show greater frictional resistance, but only when used with the smaller rectangular wires. The combined effect of environment, ligation, bracket, and archwire significantly reduced the difference. Clinically, there may, therefore, be little to choose between steel and ceramic brackets in the buccal segments, with wire choice as determined by tooth displacement being more important. Comparison of the results with those obtained using single brackets illustrates the problems of interpreting results from friction experiments. The polymeric archwire in its present form was found to be unsuitable for use in orthodontics.     

纳米银羟基磷灰石涂层陶瓷托槽的研制及力学性能研究

目的：研制新型抗菌涂层托槽,并对其表面特性及力学性能做初步研究。方法：采用微束等离子喷涂方法在托槽背板上制备涂层,采用X射线衍射仪,X荧光光谱分析仪,扫描电镜进行涂层分析。收集40颗健康离体前磨牙,随机分为两组：实验组和对照组。实验组选用纳米银羟基磷灰石涂层陶瓷托槽,对照组选用普通陶瓷托槽,并对其分别实施剪切力测试,评价托槽的力学性能。结果：此新型抗菌托槽涂层稳定均匀,厚度约100μm,涂层托槽的剪切力为7．34±1．72MPa,ARI指数平均值为1．45,满足临床要求。结论：托槽背板的涂层性能良好,且力学性能达到标准,可满足正畸临床需要。     

In vitro evaluation of frictional forces between archwires and ceramic brackets.

The aim of this study was to evaluate the frictional force between orthodontic brackets and archwires. The differences in magnitude of the frictional forces generated by ceramic brackets, ceramic brackets with metal reinforced slot, and stainless steel brackets in combination with stainless steel, nickel-titanium, and beta-titanium orthodontic archwires were investigated. Brackets and wire were tested with tip angulations of 0 degrees and 10 degrees. Friction testing was done with the Emic DL 10000 testing machine (S?o José do Rio Preto, PR, Brazil), and the wires were pulled from the slot brackets with a speed of 0.5 cm/min for 2 minutes. The ligation force between the bracket and the wire was 200 g. According to the data obtained, the brackets had frictional force values that were statistically significant in this progressive order: stainless steel bracket, ceramic bracket with a metal reinforced slot, and traditional ceramic bracket with a ceramic slot. The beta-titanium wire showed the highest statistically significant frictional force value, followed by the nickel-titanium and the stainless steel archwires, in decreasing order. The frictional force values were directly proportional to the angulation increase between the bracket and the wire.     

Enamel loss following ceramic bracket debonding: A quantitative analysis in vitro

Objective:To measure enamel surface changes after ceramic bracket debonding and after cleanup.Materials and Methods:Forty extracted teeth were scanned in three dimensions using an optical scanner (baseline). Two ceramic bracket systems were placed (19 metal-reinforced polycrystalline ceramic brackets; 21 monocrystalline ceramic brackets). Seven days later, brackets were debonded and teeth scanned (post-debond). Adhesive remnants and bracket fragments were recorded. Tooth surfaces were cleaned using a finishing carbide bur and scanned again (post-cleanup). Post-debond and post-cleanup scans were aligned with the baseline, and surface changes were quantified. Results were statistically compared using t-tests and Mann-Whitney tests (α  =  .05).Results:The depth of enamel loss (mean ± standard deviation) post-debond was 21 ± 8 µm and 33 µm and post-cleanup was 28 ± 14 µm and 18 ± 8 µm (P  =  .0191); the post-debond remnant thickness was 188 ± 113 µm and 120 ± 37 µm (P  =  .2381) and post-cleanup was 16 ± 5 µm and 15 µm for polycrystalline and monocrystalline ceramic brackets, respectively. The monocrystalline ceramic brackets predominantly left all adhesive on the tooth; the polycrystalline ceramic brackets were more likely to leave bracket fragments attached.Conclusion:Both systems allowed successful removal of the brackets with minimal enamel loss. However, the polycrystalline ceramic brackets left more fragments on the tooth, which complicated cleanup efforts.     

FAS自锁托槽与传统自锁托槽的摩擦力对比研究

目的测量FAS托槽在两种不同调节状态下与正畸钢丝之间的摩擦力大小,并与DamonⅢ和SPEED两种传统自锁托槽进行对比。方法制作尺寸放大20倍的FAS、DamonⅢ和SPEED托槽钢制模型,同时制作放大20倍的钢制圆丝和方丝,采用拉力传感器测量托槽与弓丝间摩擦力的大小。实验中FAS托槽分为两种调节状态：垫片完全收入和与弓丝平面无压力状态相切后旋转0.5圈。结果在垫片完全收入的状态下,FAS托槽与直径8.128 0 mm的不锈钢圆丝之间的动静摩擦力与DamonⅢ和SPEED托槽均无统计学差异（P>0.05）;在使用9.144 0 mm×12.700 0 mm不锈钢方丝时,FAS托槽与方丝之间的动静摩擦力与DamonⅢ托槽无统计学差异（P>0.05）,而低于SPEED托槽,且有统计学差异（P<0.05）。当垫片与弓丝平面无压力状态相切后旋转0.5圈时,FAS托槽与圆丝、方丝的动、静摩擦力均明显高于DamonⅢ和SPEED托槽（P<0.01）。结论FAS托槽可以有效调节摩擦力的大小,在无压力状态下,托槽与弓丝间的摩擦力与DamonⅢ托槽相似;在有压力状态下,可以有效锁定弓丝,防止弓丝滑动。     

Comparison of the debonding characteristics of two innovative ceramic bracket designs.

Two new ceramic brackets-one designed with a metal-lined arch wire slot and the other with an epoxy resin base-have been recently introduced. The new brackets are thought to combine the esthetic advantages of ceramics and the functional advantages of debonding metal brackets. The purpose of this study was to compare the following: 1) the shear bond strength of the 2 brackets, and 2) the bond failure location when the brackets are debonded with pliers. Sixty-one Clarity (3M Unitek) collapsible ceramic brackets and 66 MXi (TP Orthodontics, Inc) brackets were bonded to the teeth with the same bonding system. The Zwick Universal Test Machine (Zwick Gm bH & Co) was used to determine the shear bond strength force levels needed to debond the brackets. The appropriate pliers also were used to debond both types of brackets to determine the mode of bond failure that will be encountered clinically. After debonding, all the teeth and brackets were examined with 10x magnification. Any adhesive that remained after the bracket removal was assessed according to the Adhesive Remnant Index. The findings indicated that the shear bond strength of the Clarity ceramic brackets was significantly greater than that of the MXi ceramic brackets. However, both brackets exhibited forces that were adequate for clinical use. The Adhesive Remnant Index scores for both the shear test and the plier debonding indicated a similar bond failure pattern when the 2 ceramic brackets were compared with each other. This suggests that, when these brackets are debonded with the Weingart (Ormco) and ETM (Ormco) pliers, there was a greater tendency for most of the adhesive to remain on the enamel surface. In conclusion, the most efficient method to debond the MXi ceramic bracket is by placing the blades of the ETM 346 pliers between the bracket base and the enamel surface. On the other hand, the most efficient method of debonding the Clarity bracket is by using the Weingart pliers and applying pressure to the tiewings. When the 2 ceramic brackets were debonded as recommended here, most of the residual adhesive remained on the enamel surface, a pattern similar to the one observed previously with metal brackets. The failure at the bracket-adhesive interface decreases the probability of enamel damage but necessitates the removal of more residual adhesive after debonding.