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。     

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。     

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。     

纳米陶瓷涂层托槽的研制

目的:研制纳米陶瓷涂层托槽,并对托槽涂层结构表面性能进行初步研究。方法:合成尺度均一的具有光化学活性的锐钛矿型纳米态二氧化钛靶材,采用电子束物理气相沉积技术在国产金属直丝托槽表面沉积纳米二氧化钛薄膜。使用X射线衍射法和电镜观察涂层的表面性状。结果:研制生产出纳米二氧化钛陶瓷涂层托槽,托槽表面沉积二氧化钛薄膜厚度约 5~8μm。二氧化钛晶粒尺寸均一,分布均匀,表面光洁度高。结论:托槽表面纳米二氧化钛镀膜对托槽槽沟尺寸几乎无影响,且具有良好表面性状及光化学活性,可以满足口腔正畸临床需要。     

自制美学涂层弓丝表面形貌的研究

目的：对自制美学涂层弓丝表面粗糙度进行测试,并与传统不锈钢弓丝进行比较,在扫描电镜下观察弓丝的表面形貌。方法：分别测定经4种托槽（带金属槽沟的陶瓷托槽,普通托槽,陶瓷托槽,树脂托槽）摩擦过的及未经摩擦的0.018英寸的美学涂层不锈钢圆丝和0.018英寸的不锈钢圆丝的表面粗糙度,并在扫描电镜下观察弓丝的形貌特征。结果：未经摩擦过的涂层与未涂层弓丝间的表面粗糙度比较,无统计学意义;经托槽摩擦过的涂层与未涂层弓丝间的表面粗糙度比较,有统计学意义,且与不同托槽摩擦后弓丝表面粗糙度值不同,其中,与陶瓷托槽摩擦后的弓丝表面粗糙度和与带金属槽沟的陶瓷托槽,普通托槽及未摩擦的弓丝表面粗糙度存在统计学差异。结论：美学涂层弓丝符合口腔正畸临床使用要求。     

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。     

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目的    探讨不同处理方法对陶瓷托槽再黏结抗剪切强度的影响,为临床应用提供依据。方法    选取2009年2—7月厦门市口腔医院正畸科患者中因正畸需要而拔除的健康双尖牙70颗,随机抽取30颗用于制备脱落陶瓷托槽,其余40颗用于黏结实验。将40颗用于黏结实验的牙随机分成4组（每组10颗）：新陶瓷托槽组,烧灼处理组,喷砂处理组,硅涂层处理组。陶瓷托槽黏结于未经酸蚀处理的微湿的离体牙上,然后用去托槽钳小心取下,形成脱落托槽。分别对陶瓷托槽底面进行烧灼处理、喷砂处理、硅涂层处理;不同方法处理后,各组托槽底面常规涂硅烷偶联剂。每组离体牙经常规牙面处理后,分别黏结新陶瓷托槽及脱落后处理的陶瓷托槽,测定并比较各组抗剪切强度。结果    新陶瓷托槽、烧灼处理、喷砂处理、硅涂层处理组抗剪切强度依次为（12.4733±3.4326）MPa、（7.2375±1.6914 ）MPa、（9.1612±1.3261）MPa、（13.1671±5.0392）MPa;烧灼组和喷砂组抗剪切强度与新托槽组和硅涂层差别有统计学意义（P < 0.05）,硅涂层组与新托槽组之间的差别无统计学意义（P > 0.05）。结论    陶瓷托槽经烧灼处理及喷砂处理后再黏结其抗剪切强度均有下降,硅涂层处理后其抗剪切强度与新托槽相近。     

纳米TiO2陶瓷涂层托槽周边菌斑附着研究

目的：评估纳米TiO2陶瓷涂层托槽周边菌斑附着情况。方法：选择20例正畸拔牙矫治病例,于待拔除前磨牙粘接自行研制的纳米TiO2陶瓷涂层直丝弓托槽。托槽粘接后1周、2周和3周拔除测试牙,电镜扫描观察托槽周边区域、托槽龈方区域菌斑附着。结果：①托槽周边区域存在大量多余粘接剂,表面粗糙且粘接剂．釉质间存在明显间隙;②大量菌斑附着,托槽龈方区域清洁困难,菌斑附着较多;③托槽粘接后2周、3周时,托槽周边区域粘接剂表面菌斑成熟,而托槽龈方近牙颈部区域菌斑尚处于形成初期。结论：托槽粘接后,托槽周边区域及龈方近牙颈部区域是菌斑聚集的主要区域。     

不同处理方法对陶瓷托槽再粘接强度的影响

目的通过观察不同的脱落陶瓷托槽底板处理方法对其抗剪切强度、粘接剂残留指数的影响,探讨适合临床椅旁操作的脱落陶瓷托槽再粘接底板处理方法。方法用TranscendTMSeries 6000陶瓷托槽制取脱落托槽75颗,随机平均分为五组:机械磨除组、喷砂组、硅烷组、Al2O3涂层组、硅涂层组。分别用五种不同方法处理托槽底板,新托槽15颗作对照组,扫描电镜观察和能谱分析后,以UniteTMBonding Adhesive粘接剂粘接到离体牙,水浴和冷热循环后抗剪切强度测定和粘接剂残留指数观察。统计学分析实验结果。结果抗剪切强度:新托槽组11.20±3.33,硅涂层组9.43±2.93MPa,Al2O3涂层组8.83±2.65MPa,机械磨除组4.67±2.70 MPa,硅烷组3.51±1.31MPa,喷砂组2.44±1.43MPa。粘接剂残留指数各组无显著性差异(P>0.01)。结论在实验的不同脱落陶瓷托槽底板处理方法中,硅涂层组和Al2O3涂层组均达到有效粘接强度,机械磨除组、喷砂组、硅烷组没有达到有效粘接强度。     

机械法去除国产陶瓷托槽安全性的研究

目的使用去托槽钳去除两种底板设计的国产多晶体氧化铝陶瓷托槽,评价对牙齿安全性的影响。方法选择离体上、下颌各15颗双尖牙,随机分为3组。实验组为国产沟槽底板（3条横沟）和网格底板（3×3网格）陶瓷托槽,对照组为临床常用多晶体氧化铝陶瓷托槽（Crystaline IV）。使用37%液体磷酸和京津釉质粘接剂分别粘接上述3种托槽,在0.9%生理盐水中室温保存24h。使用去托槽钳及WDW3050型微机控制电子万能试验机龈向施加剪切力,检测去除强度、粘接剂残留指数（ARI）及托槽断裂个数,并以立体显微镜评价釉质表面损伤情况。结果国产沟槽底板、网格底板陶瓷托槽及Crystaline IV的去除强度分别为18.49±4.00MPa、17.89±4.13MPa和17.62±4.51MPa,三者间无显著性差异。主要去除部位均在粘接剂内部,托槽断裂个数分别为7个、7个和6个。各有一颗使用国产沟槽底板陶瓷托槽和Crystaline IV的牙齿在立体显微镜下发现明显的釉质缺损。结论对于唇面呈弧形的牙体,使用去托槽钳龈向施加剪切力去除国产多晶体氧化铝陶瓷托槽时,去除强度大,易发生托槽断裂,且可能并发釉质剥脱,并不是理想方法。     

喷砂处理对不同底面设计陶瓷托槽再粘接影响的实验研究

目的：探讨喷砂处理对不同底面设计的陶瓷托槽再粘接抗剪切强度的影响。方法：选取90颗因正畸拔除的健康前磨牙,随机抽取30颗用于制备脱落陶瓷托槽,其余60颗用于粘接实验。将60颗牙根据不同底面设计分成3大组：微隐窝底面组（A组）、微晶体底面组（B组）、树脂底面组（C组）,每大组分成2小组：新托槽组（n）、喷砂组（sb）,每组10颗牙。陶瓷托槽粘接于未经酸蚀处理的微湿的离体牙上,然后用去托槽钳小心取下,形成脱落托槽,对托槽底面进行喷砂处理,并在底面常规涂硅烷偶联剂。离体牙经常规牙面处理后,分别粘接新托槽及处理后的托槽,测定并比较各组抗剪切强度。结果：三组托槽初次粘接及再次粘接抗剪切强度分别为（12．4733±3．4326）Mpa和（9．1612±1．3261） Mpa;（12．7374±3．8999）Mpa和（6．7152±3．1876）Mpa;（9．5022±1．8801）Mpa和（6．6281±2．1187）Mpa,其中A组的抗剪切强度大于B组和C组的抗剪切强度,差别有统计学意义（P＜0．05）;B组和C组两者的抗剪切强度有差别,但无统计学意义（P＞0．05）。结论：三组陶瓷托槽再粘接抗剪切强度明显下降,但高于正畸临床所需的最低抗剪切强度值。其中微隐窝底面与微晶底面和聚合体网底相比,抗剪切强度下降最少,更适合喷砂处理。     

Bond strength of disinfected metal and ceramic brackets: an in vitro study

The aim of this in vitro investigation was to test whether disinfecting with Chlorhexamed fluid had an influence on the shear bond strength of metal and ceramic orthodontic brackets. Metal and ceramic brackets were fixed by the composite adhesives Transbond XT (light curing) and Concise (chemical curing) to 224 bovine permanent mandibular incisors. Bovine teeth were divided into eight groups of 28 each as group 1: metal bracket/Transbond XT, group 2: disinfected metal bracket/Transbond XT, group 3: metal bracket/Concise, group 4: disinfected metal bracket/Concise, group 5: ceramic bracket/Transbond XT, group 6: disinfected ceramic bracket/Transbond XT, group 7: ceramic bracket/Concise, and group 8: disinfected ceramic bracket/Concise. Adhesive bonding was done according to the manufacturers' instructions. As shown by group comparison (Kruskal-Wallis test, univariate analysis of variance, P < .001), the disinfection of metal brackets had no statistically relevant influence on shear bond strength (P = .454). However, disinfecting ceramic brackets with either adhesive led to a significant reduction in shear bond strength compared with the untreated ceramic bracket group (P < .001). The Fisher's exact test of the Adhesive Remnant Index (ARI) scores showed a significant difference within the metal group bonded with different adhesives (P = .0003). The ARI scores 1 and 2 were not reached by the ceramic bracket groups. The disinfection of the ceramic brackets is a suitable procedure for clinical use because the measured shear bond strength values were higher than 6-8 MPa required in orthodontics.     

Shear bond strength of ceramic brackets with chemical or mechanical retention.

The study was undertaken to measure and compare the shear bond strengths of a ceramic bracket with chemical retention, a ceramic bracket with a new type of textured base providing mechanical retention, and a metal bracket with foil-mesh base. The tests were performed on 51 extracted human premolars which were randomly divided into three equally large groups (n = 17)--one group for each type of bracket. After debonding, the site of failure was noted and the enamel surface inspected with scanning electron microscopy. The ceramic bracket with chemical retention exhibited significantly higher bond strength than the corresponding bracket with textured base. In comparison with the metal bracket significantly higher bond strengths were recorded for both types of ceramic brackets. The ceramic bracket with mechanical retention and the metal bracket were comparable as regards the site of bond failure. In some cases the chemical bond provided very high values of bond strength. Enamel failure were recorded in three teeth which had been bonded with this type of ceramic bracket.     

Shear, torsional, and tensile bond strengths of ceramic brackets using three adhesive filler concentrations

The effect of changes in adhesive filler concentration on the shear, torsional, and tensile bond strength of a chemical, a mechanical, and a chemical/mechanical retained ceramic bracket was evaluated. Two hundred ten bovine teeth were bonded with one of three ceramic brackets using a 30%, 55%, or 80% filled adhesive. The brackets were debonded with a shear, torsional, or tensile force to test the bond strength and the site of bond failure. No significant difference was found in the shear, torsional, or tensile bond strength of each ceramic bracket type in relation to changes in the adhesive filler concentration. However, there was a trend toward increased bond strength with increasing filler concentration. Combining the data according to adhesive type revealed that the 80% filled adhesive displayed a significantly greater shear bond strength than the 30% or 55% filled adhesive and a greater torsional bond strength than the 30% filled adhesive. This supports the hypothesis of increased bond strength with increased adhesive filler concentration. The mechanically retained ceramic bracket showed greater shear bond strength and maximum shear bond strength in torsion than the chemical or chemical/mechanical retained ceramic bracket. The tensile bond strength of the mechanically retained ceramic bracket was similar to that of metal brackets reported in other studies, and the failure site was at the bracket-adhesive interface.     

The effect of variation in mesh-base design on the shear bond strength of orthodontic brackets

This study compared the shear bond strengths of two metallic orthodontic brackets, one with a single-mesh bracket base and the other with a double-mesh bracket base. The Transbond XT adhesive system was used to bond all brackets to the teeth. Two types of brackets were compared, ie, 20 Ovation metal bracket series, with a double-mesh base (Super-mesh) and an 81.50 gauge (0.126 inch), and 20 Victory series metal brackets that have a miniature single-mesh base. The teeth were bonded and debonded within half an hour from the initial bonding. The enamel surface was examined under 10x magnification to determine how much residual adhesive remained on the tooth. Student's t-test was used to compare the shear bond strength of the two groups. Chi-square test was used to compare the adhesive remnant index (ARI) scores for the two bracket types. The mean shear bond strength for the double-mesh brackets was 5.2 +/- 3.9 MPa and for the single-mesh brackets was 5.8 +/- 2.8 MPa. The t-test comparisons indicated that they were not significantly different from each other (P = .157). The ARI comparisons indicated that both bracket types had similar bracket failure modes and were not significantly different from each other (chi2 = 2.0, P = .5). These results indicated that single- and double-mesh bracket bases have comparable shear bond strength and bracket failure modes.     

A comparison of shear bond strengths of metal and ceramic brackets

The study measures and compares shear bond strength data obtained from metal, ceramic, and ceramic-filled plastic brackets bonded to human incisor teeth with a heavily filled composite resin. The mean values for groups of different types of brackets were not statistically significant. The site of failure was commonly at the resin/bracket interface except for the ceramic-filled plastic brackets, which frequently showed failure of the bracket itself. One group of ceramic brackets that used no mechanical retention often showed failure to the extent that the bulk of resin remained on the bracket. The findings strongly suggest that ceramic brackets should offer a viable alternative to their metal counterparts because they combine esthetics with a bond strength that is comparable to and as reliable as their metal counterparts.     

2种不同底板托槽粘结强度的比较

目的 对网底托槽和激光底面托槽粘接强度进行比较研究,为临床选用金属托槽提供参考。方法 挑选对称性拔除第一前磨牙正畸患者20例,分2组,分别粘结激光底面托槽以及网底进口金属托槽,采用同样的方法及相同的步骤进行粘接。对患者托槽脱落情况作6个月的追踪观察每月复诊时并记录。采用同一患者拔除的前磨牙为实验样本,粘结与口内对应托槽,以材料力学实验机分别对其进行体外即刻抗剪切强度(SBS)的测定。结果 临床观察发现网底托槽脱落率大于激光底面托槽,体外实验也表明激光优化底板托槽剪切强度大于网底托槽,且差别具有统计学意义(P<0.05)。结论 托槽底板结构可影响托槽粘结强度,但两者都能很好满足临床正畸粘结需要。     

A comparison of shear bond strengths between new and recycled ceramic brackets

The recycling of 'used' ceramic brackets in the orthodontic surgery has been previously described. The present study investigated the shear bond strength of both recycled and new ceramic brackets. The mean shear bond strengths of the new and recycled ceramic brackets were 259.7 +/- 88.2 N and 187.2 +/- 60.8 N, respectively. Although significantly lower (P less than 0.01), the bond strength of recycled ceramic brackets appeared to be clinically adequate. There appeared to be little difference in the variation in bond strength between the new and recycled ceramic bracket group. Our results showed that the site of bond failure depended on the magnitude of bond strength. Scanning electron micrograph examination of the failure sites showed enamel fracture in one sample where the bond strength was extremely high.