可调节式磨耗仪在牙磨耗实验中的应用

目的:验证自主研发的可调节式磨耗仪在磨耗实验中应用的可行性。方法:以软质钴铬合金作为对磨材料样本,牙釉质为磨耗样本,用配对分组实验方法,将牙釉质样本分为A、B 2组进行磨耗实验,定量检测牙釉质样本的磨耗量,采用SAS14.0软件包对数据进行统计学分析,评价磨耗仪在磨耗实验应用中的可行性。结果:将A组和B组牙釉质样本磨痕深度值进行配对t检验分析,得到P=0.7464。2组牙釉质样本磨痕深度值的差异无显著性。结论:磨耗仪能够提供较为稳定的磨耗实验环境,磨耗结果变异较小,较为精确。     

不同口腔修复材料与天然牙耐磨性能的比较

目的：通过体外模拟实验对几种口腔修复材料与天然牙釉质的磨耗性能进行对比研究并探讨其机制.方法：（1）将钴铬合金,纯钛,氧化锆陶瓷,Ceramage聚合瓷制成符合规格的试件.（2）将上颌第一前磨牙磨改,作为对照组.（3）将滑石瓷制做圆盘状,作为与试件及天然牙对磨的材料.（4）所有实验均在人工唾液环境中加载测试.（5）SPSS17.0软件进行统计学处理,对磨耗后的试件进行磨痕形貌的观察.结果：（1）纯钛的磨耗量与牙釉质最接近.钴铬合金与氧化锆陶瓷无统计学意义（P＞0.05）,其余各组之间均有统计学意义（P＞0.05）.磨耗后质量损失量的大小顺序为纯钛＞牙釉质＞ Ceramage聚合瓷＞氧化锆陶瓷＞钴铬合金.（2）钴铬合金：磨粒磨损,同时伴有粘着磨损.纯钛：以粘着磨耗为主,伴有磨粒磨耗.氧化锆陶瓷：磨粒磨损.Ceramage聚合瓷：主要是磨粒磨损和粘着磨损,伴有疲劳磨损.天然牙：粘着磨损和磨粒磨损.结论：（1）纯钛的耐磨性低于牙釉质但与牙釉质最为相近,是一种良好的修复材料.（2）钴铬合金与氧化锆陶瓷的耐磨性能接近,均可对天然牙釉质造成过度磨耗.（3）修复材料的耐磨性能受其微观结构的影响.     

三种烤瓷铸造合金的抗腐蚀性能研究

目的 研究3种常用烤瓷非贵金属合金在体外细胞培养液和1%乳酸液中离子析出的量及种类.方法 用失蜡法铸造3种常用烤瓷非贵金属合金试件:镍铬合金、钴铬合金、镍钛合金,分别置于DMEM体外细胞培养液和1%乳酸溶液中浸泡30 d后,用电感耦合等离子发射光谱法(inductively coupled plasma atomic emission spectroscopy,ICP-AES)检测3种合金离子的析出量和种类,扫描电镜对其表面形态进行分析.结果 3种合金在两种浸泡液中离子析出总量依次为镍铬合金＞钴铬合金＞镍钛合金;在1%乳酸溶液中浸泡的3种合金离子析出总量皆比在DMEM细胞培养液中的离子总量增加,差异具有统计学意义(P＜0.05).结论 3种常用烤瓷非贵金属合金中,镍铬合金的离子析出量最大,耐腐蚀性能最差,镍钛合金和钴铬合金耐腐蚀性比镍铬合金好;1%的乳酸溶液加速3种合金的腐蚀过程.     

口腔内3种合金共存下的离子析出及表面粗糙度的改变

目的：研究口腔内3种合金共存下的离子析出及表面粗糙度的改变,为临床合金修复材料的选择提供参考。方法：制作镍铬合金、钴铬合金和金银钯合金标准试件,分为镍铬合金（N组）、钴铬合金（C组）、金银钯合金（A组）、镍铬合金与金银钯合金（NA组）和镍铬合金与钴铬合金（NC组）5组。浸泡于标准电解质溶液（T=37 ℃,pH=2.31）中,每组平行重复4次。7 d后,用电感耦合等离子体质谱仪检测各组浸提液中离子析出量;用原子力显微镜观察各组试件表面形貌,测量表面粗糙度。采用SPSS 18.0软件包对数据进行统计学分析。结果：析出的镍离子量N组为（1.32±0.03） μg/cm², NA组为(2.13±0.07) μg/cm²,NC组为(1.53±0.08) μg/cm²,NA组、NC组均显著多于N组,NA组显著多于NC组（P<0.05）;析出的铬离子量N组为(0.06±0.01) μg/cm²,NA组为(0.08±0.01) μg/cm²,NC组为(0.05±0.01) μg/cm²,NA组显著多于NC组（P<0.05）。镍铬合金的表面粗糙度N组为(4.60±0.16) nm,NA组为(5.37±0.08) nm,NC组为(5.04±0.15) nm,NA组、NC组均显著大于N组,NA组显著大于NC组（P<0.05）。镍铬合金与金银钯合金或钴铬合金共存时,析出的镍离子量比其单独使用时明显增多,其表面粗糙度明显增大;镍铬合金与金银钯合金共存时比镍铬合金与钴铬合金共存时析出的镍、铬离子量多,镍铬合金的表面粗糙度也大。结论：临床上应尽量避免在患者口腔内同时应用镍铬合金与金银钯合金,或镍铬合金与钴铬合金,尽量避免贱金属的临床使用。     

两种冠修复材料与变形链球菌粘附的关系

目的了解表面粗糙度相同的镍铬合金、钴铬合金与变形链球菌粘附的关系。方法用镍铬合金、钴铬合金分别加工相同的试件各10个,对试件表面进行打磨,用TR200手持式粗糙度仪测出表面粗糙度参数,使2种修复材料试件表面粗糙度相似;将2组试件分别在变形链球菌菌液中培养48h,记录粘附菌量。结果镍铬合金和钴铬合金上粘附菌量分别为（3.128±1.020）×10^6和（4.704±1.502）×10^6,两者之间差异有统计学意义（t=2.745,α=0.05,P=0.013）。结论在表面粗糙度相似时,镍铬合金上的变形链球菌粘附量少于钴铬合金。     

3种牙科铸造金属模拟唾液浸泡后粗糙度的变化

目的：通过考察钴铬合金、镍铬合金以及纯钛在不同pH值人工唾液中浸泡后表面粗糙度的变化，研究3种常用牙科金属的耐腐蚀能力。方法：将3种金属的标准铸造试件逐级打磨抛光后。浸泡于pH值分别为7．0和5．6的人工唾液中。3个月后检测试件表面粗糙度，并用金相显微镜观察试件表面。采用SPSS11．0软件包对数据进行单因素方差分析及t检验。结果：pH=5．6的人工唾液浸泡后，3种材料表面粗糙度有显著差异，镍铬合金〉钴铬合金〉纯钛金属（P〈0．01）。pH=7．0的人工唾液浸泡后，镍铬合金表面粗糙度大于钴铬合金和纯钛（P〈0．01），但钴铬合金和纯钛之间无统计学差异（p〉0．05）。pH=5．6人工唾液浸泡组的镍铬合金和钴铬合金表面粗糙度大于pH=7．0组的同种材料（P〈0．01）。各试验组表面粗糙度大小与显微镜观察到的材料表面腐蚀程度一致。结论：纯钛在酸性和中性环境下均有较强的耐腐蚀性，钴铬合金、镍铬合金在酸性介质中的耐腐蚀性较差。3种金属的耐腐蚀性由大到小排列为：纯钛金属〉钴铬合金〉镍铬合金。     

6种不同修复材料与天然牙牙釉质摩擦、磨耗性能的比较

目的：通过体外摩擦、磨耗实验，比较临床常用的陶瓷材料、多种合金及天然牙釉质的摩擦、磨耗性能，为临床上选择与对颌牙磨耗性能相近的修复材料，更好地保护对颌牙提供一定的实验依据。方法：将陶瓷、纯钛、钛合金、镍铬合金、金钯合金、银汞合金和近期拔除的成人下颌第三磨牙的釉质平面，与滑石瓷磨头磨耗机上对磨。耐磨性能的评定采用称重法。用针一盘磨损试验仪测定各种材料的滑动摩擦系数。应用SPSS11．5软件包进行统计学处理．对各试件、天然牙的质量损失量进行统计学分析，对比分析摩擦系数。结果：单位面积的磨损量以天然牙釉质最小，但与瓷块、银汞合金、金钯合金无显著性差异（P〉0．05），与其余各组均有显著性差异（P〈0．01）；纯钛最大，与其余各组均有显著性差异（P〈0．01），镍铬合金、金钯合金与其余各组均有显著性差异（P〈0．01）。瓷块的摩擦系数稳定在0．68，银汞合金的摩擦系数为0．12，金钯合金的摩擦系数为0．11，镍铬合金为0.41，纯钛为0.38，钛合金为0．48，天然牙釉质为0．65。结论：6种修复材料的耐磨性均比天然牙釉质差．纯钛的耐磨性最小，钛合金及镍铬合金、金钯合金次之，陶瓷的耐磨性最大。     

两种镍基口腔修复合金在漱口水中镍离子析出的比较

目的：通过连续浸泡实验探究两种镍基口腔修复常用合金在漱口水中的镍离子析出情况。方法将镍基铸造合金和镍铬烤瓷合金的标准试件逐级打磨后,放在分别由漱口水、蒸馏水和人工唾液配制的实验组和对照组溶液中,连续恒温（37±1）℃浸泡96 h后,使用电感耦合等离子体发射光谱仪（ICP-OES）测定溶液中析出的镍离子的量。结果在没有金属浸泡的空白对照的实验组和对照组溶液中镍离子含量低于ICP-OES的检出限。在对照组溶液及实验组溶液中浸泡后镍基铸造合金组测得的镍离子析出均大于镍铬烤瓷合金组。两种金属试件在实验组溶液中的析出均大于在对照组溶液中的析出,差异明显。结论漱口水对两种镍基合金中镍离子的析出均有促进作用,其中又以镍基铸造合金为甚。     

常用牙科合金与铁铬钼软磁合金激光焊接件的拉伸性能评价

目的:评价激光焊接常用牙科合金与铁铬钼软磁合金后的拉伸性能.方法:铸造钴铬合金、镍铬合金拉伸试件,随机分组并分别与铁铬钳软磁合金试件用激光焊接机焊接,以激光焊接同种钻铬合金拉伸试件为对照组.利用万能拉伸试验机测试焊接后试件的抗拉强度、0.2%屈服强度,利用扫描电镜分析断裂口,并分别进行比较.结果:激光焊接铁铬钼软磁合金与钴铬合金、镍铬合金的扰拉强度、0.2%屈服强度与激光焊接同种钴铬合金无统计学差别.激光焊接铁铬钼合金与镍铬合金的断裂口呈韧件断裂,激光焊接铁铬钼合金与钴铬合金的断裂口呈韧性-解理混合型断裂,而激光焊接钻铬合金的断口呈准解理断裂.结论:从拉伸性能方面考虑,激光焊接铁铬铜软磁合金与钴铬合金、镍铬合金可应用于磁性固位体构件的焊接.     

白色念珠菌对钛合金及钴铬合金腐蚀影响的研究

目的研究口腔白色念珠菌对钛合金及钴铬合金腐蚀的影响。方法将钛合金和钴铬合金随机分成空白对照组,实验对照组及实验组。在需氧环境中将白色念珠菌接种到沙保罗葡萄糖液体培养基中,试件浸在培养基中,每周更换1次培养基,并接种1次,共20周。然后用表面轮廓仪测定表面粗糙度,并进行统计学分析。结果钛合金试件空白组、实验对照组、实验组金属试件表面粗糙度均值总体之间差异无显著性。钴铬合金试件空白组、实验对照组、实验组组金属试件均值总体之间差异有显著性,两两比较,各组间差异均有显著性。结论白色念珠菌黏附钛合金表面短时间内金属表面粗糙度无明显变化,黏附钴铬合金表面粗糙度变化明显。     

Simulated enamel wear during occlusal contact

PURPOSE: To investigate in vitro rates of wear for human enamel that opposes human enamel by means of two-body and three-body wear tests. METHODS: Flattened surfaces (1000-grit) of molars and hemi-spherically prepared enamel cusps were perpendicularly opposed and loaded (75.6 N, 1.2 Hz) cyclically 100,000 times in both two- and three-body wear test conditions. Wear depths of flat enamel specimens were measured with a profilometer, and those of stylus enamel specimens were determined by a computer digitizing system at 5, 10, 25, 50, and 100 thousand cycles. Data were statistically analyzed by three-way ANOVA (P < 0.05), and differences between two-body and three-body wear data on flat and stylus enamel specimens were determined by Bonferroni-Dunn test. RESULTS: The amount of wear after 100,000 cycles in the two-body wear test was 175.6 +/- 144.6 microm for flat enamel specimens and 199.3 +/- 72.7 microm for stylus samples. Flat enamel, three-body specimens wore 4.9 +/- 1.4 microm and the stylus samples wore 4.3 +/- 1.0 microm. The data for both flat and stylus enamel specimens subjected to the two-body test were significantly greater than those of the three-body wear test (P < 0.001).     

Esthetic restorative materials and opposing enamel wear

This in vitro study compared the effects of a gold alloy (Degulor M), four dental ceramics (IPS Empress, IPS Empress 2, Duceram Plus, Duceram LFC) and a laboratory-processed composite (Targis) on the wear of human enamel. The amount of wear of the enamel (dental cusps) and restorative materials (disks) were tested in water at 37 degrees C under standard load (20 N), with a chewing rate of 1.3 Hz and was determined after 150,000 and 300,000 cycles. Before the test, the average surface roughness of the restorative materials was analyzed using the Ra parameter. The results of this study indicate that Targis caused enamel wear similar to Degulor M and resulted in significantly less wear than all the ceramics tested. IPS Empress provoked the greatest amount of enamel wear and Degulor M caused less vertical dimension loss. Targis could be an appropriate alternative material to ceramic, because it is esthetic and produces opposing enamel wear comparable to gold alloy.     

In vitro wear assessment of titanium alloy teeth

PURPOSE: Wear of commercially pure (CP) titanium prosthetic teeth has frequently been observed. The greatest wear has been found when the same grades of CP titanium are used for both maxillary and mandibular teeth. This study examined the wear behavior of teeth made with cast titanium alloy and compared these results with those for CP titanium and gold alloy teeth. MATERIALS AND METHODS: All tooth specimens were cast with grade 3 alpha titanium, 3 metastable beta alloys [Ti-15Mo-2.8Nb-0.2Si (Timetal 21 SRx), Ti-13Nb-13Zr, and Ti-15V-3Cr-3Sn-3Al], and 2 alpha+beta alloys (Ti-6Al-7Nb and Ti-6Al-4V). As a control, Type IV gold alloy was also cast conventionally. All teeth (both maxillary and mandibular) were secured in an in vitro 2-body wear testing apparatus that simulated chewing function (60 strokes/min; grinding distance, 2 mm under flowing water). Wear resistance was assessed as volume loss (mm(3)) at 5 kgf (grinding force) after 50,000 strokes. The results (n = 5) were analyzed using analysis of variance or Fisher's exact test (alpha = 0.05). RESULTS: Of the titanium teeth, the wear of 2 of the metastable beta alloys (Timetal 21 SRx and Ti-15V-3Cr-3Sn-3Al) was found to be significantly (p <0.05) higher than that of CP titanium and the 2 alpha+beta alloys. The Type IV gold alloy exhibited better wear resistance than all of the titanium teeth tested. No correlation was found between wear loss and hardness among all the metals tested. CONCLUSIONS: Among the titanium teeth examined, the alpha+beta alloys exhibited significantly less wear than the other types of titanium. The dental casting gold alloy tested exhibited the best wear resistance among all of the metals tested.     

二氧化锆与钴铬合金修复体精细抛光后对天然牙磨耗的影响

［摘要］ 目的 研究临床上精细抛光对二氧化锆及钴铬合金修复体材料与天然牙间磨耗的影响。方法 使用表面粗糙度仪测量修复体材料抛光前后的粗糙度值（Ra）。在摩擦磨损测试机上,模拟口腔内的力学和化学环境,进行天然牙与不同处理的修复体材料间的摩擦磨损实验,测量两者间摩擦系数（μ）。测量实验前后各磨擦对象的自身质量损失（Δm）,扫描电镜观察实验后天然牙表面。结果 各实验组中表面Ra,不烧结饰瓷抛光组（0.933±0.186）μm小于不抛光组（2.350±0.327）μm（P=0.000）;烧结饰瓷组抛光组（2.300±0.189）μm小于不抛光组（4.200±0.871）μm（P=0.000）;钴铬合金抛光组（0.250±0.083）μm小于不抛光组（1.200±0.894）μm（P=0.000）,有统计学意义。对磨天然牙自身质量损失量（Δm）,不烧结饰瓷抛光组（6.067±0.921）mg小于不抛光组（16.690±2.113）mg（P=0.001）;烧结饰瓷抛光组（5.893±0.838）mg小于不抛光组（14.016±0.063）mg（P=0.000）;钴铬合金抛光组（4.573±1.954）mg小于不抛光组（11.433±1.087）mg（P=0.008）有统计学意义。各组修复材料自身质量损失量（Δm）不烧结饰瓷抛光组（0.300±0.010）mg小于不抛光组（0.800±0.010）mg（P=0.001）;烧结饰瓷抛光组（0.456±0.055）mg小于不抛光组（0.650±0.086）mg（P=0.031）;钴铬合金抛光组（10.236±0.357）mg小于不抛光组（14.300±0.526）mg（P=0.000）有统计学意义。抛光组的摩擦系数：不烧结饰瓷氧化锆0.068,烧结饰瓷热氧化锆0.095,钴铬合金0.063明显小于不抛光组不烧结饰瓷二氧化锆0.096,烧结饰瓷二氧化锆0.119,钴铬合金0.103,差异有统计学意义。结论 修复体表面精细抛光,可以有效降低其表面粗糙度,减小其与牙釉质间的摩擦系数,避免天然牙的过度磨耗。     

Wear resistance and surface roughness of a newly devised adhesive patch for sealing smooth enamel surfaces

A laboratory study assessed the wear resistance and surface roughness after chemical and mechanical wear of a newly devised adhesive patch when used as a smooth surface sealant. Forty-eight enamel discs were prepared from bovine lower central incisors. Sixteen specimens were treated with one of two sealing options: the prototype of an adhesive patch or a flowable resin. Unsealed enamel served as the positive control. Wear and surface roughness was measured at baseline and after all the samples were immersed in saliva or lactic acid (n=8 per treatment group) for up to 21 days, during which the experimental and control enamel surfaces were exposed to 10 double-stroke toothbrush cycles per day. In saliva and lactic acid, the sealed specimens showed no significant wear during the observation period (p=0.1841). Only untreated specimens exposed to lactic acid showed a significant substance loss after 14 and 21 days (p=0.0186). The patch and flowable resin showed no differences in surface roughness values at respective times (p=0.385); whereas the surface roughness of the unsealed specimens in lactic acid was significantly higher (p<0.0001). It was concluded that the adhesive patch under investigation merits further study to assess its potential as a sealant for smooth enamel surfaces.     

Analysis of composite type and different sources of polymerization light on in vitro toothbrush/dentifrice abrasion resistance

OBJECTIVES: This study examined toothbrush/dentifrice abrasion of a photo-activated prosthetic composite (dentin and enamel variations) for the purpose of evaluating the influence of polymerization sources on abrasive wear. METHODS: A photo-activated prosthetic composite material (Artglass) was assessed. Dentin and enamel variations were polymerized using a proprietary photo-curing unit with two xenon stroboscopic lamps (UniXS), and other enamel specimens were polymerized either with a laboratory photo-curing unit with three fluorescent tubes or with a high intensity unit with two metal halide lamps. All specimens were stored in water for 14days and subjected to toothbrush/dentifrice abrasion (350g vertical load) using an abrasive slurry (Colgate Fluoriguard) and a toothbrush (Oral-B 40). The amount of vertical loss and the surface roughness of the specimens after 20,000 strokes were determined by profilometer. Average values of groups of five specimens were compared using analysis of variance (ANOVA) and Sheffe's S intervals (p<0.05). RESULTS: When polymerizing with the proprietary unit, the abrasion and surface roughness of the enamel material required respective means of 34.08microm (+/-3.66) and 1.00microm (+/-0.08), and the those of the dentin material required means of 42.02microm (+/-5.62) and 1.23microm (+/-0.20). Both abrasion and surface roughness after toothbrushing of the enamel material were significantly smaller than were those of the dentin material. The abrasion of specimens polymerized with the metal halide unit required a mean of 23.89microm (+/-6.17) and demonstrated minimal wear. CONCLUSIONS: The use of a high intensity metal halide photo-curing unit effectively enhanced the abrasion resistance of the composite. Surfaces of restorations should be covered with the enamel material in order to achieve smoothness and wear resistance.     

Comparison of castability and surface roughness of commercially pure titanium and cobalt-chromium denture frameworks.

STATEMENT OF PROBLEM: Titanium is a biocompatible material, but it is not widely used in clinical dentistry for conventional removable denture frameworks. Little research exists on its applicability. PURPOSE: This study compared the casting accuracy and roughness of titanium and cobalt-chromium denture frameworks. MATERIAL AND METHODS: Twenty Kennedy Class II, Division 1 removable partial denture frameworks were fabricated with commercially pure titanium (n = 10) and a cobalt-chromium alloy (n = 10). The casting accuracy of each framework was determined by visual, radiographic, and microscopic methods. The roughness of each polished framework surface was analyzed with atomic force microscopy. RESULTS: The clinical fit, porosities, and microporosities of both types of metal frameworks were qualitatively similar. The surface roughness of polished pure titanium and cobalt-chromium frameworks was 104.43 +/- 69.24 nm and 133.91 +/- 40.92 nm, respectively. This difference was not statistically significant (P >.05). CONCLUSION: The clinical fit, porosity, and surface roughness of the titanium and cobalt-chromium frameworks fabricated for this study were comparable.     

激光表面强化技术对牙科钴铬合金机械性能影响的研究

目的：研究激光表面强化技术对牙科钴铬合金机械性能的影响。方法：选用临床上常用的钴铬合金作为实验对象,并制成检测试件,进行激光表面强化处理,扫描电镜观察合金表面金相结构及形貌的变化;并测试试件表面硬度及耐磨性的改变,结果进行统计学分析。结果：激光表面强化后,合金晶粒得到细化;表面硬度及耐磨性得到提高（P〈0.01）。结论：激光表面强化技术有明显改善牙科钴铬合金机械性能的作用。     

Tooth wear prevention: a quantitative and qualitative in vitro study

BACKGROUND: Management of tooth wear from grinding presents a significant clinical challenge. Acrylic nightguards are often used to protect the teeth, but many patients still grind with these appliances. This study aimed to test the effectiveness of three lubricants in reducing enamel wear by using an electro-mechanical machine under controlled conditions, with a view to undertaking a subsequent longitudinal clinical study. METHODS: Sectioned tooth specimens were worn against each other under different loads and with the addition of three different lubricants: calcium fluoride (CaF) powder, olive-oil, and a combination of calcium fluoride with olive-oil in the form of a slurry. Wear rates of enamel only were quantified by weighing the specimens, and resin replicas of the worn tooth surfaces were made for examination under a scanning electron microscope. RESULTS: All three lubricants reduced the amount of enamel wear significantly compared with wearing specimens without adding lubricants. Wear rate was influenced by the type of lubricant and the load applied. Wear rates were significantly less for olive-oil and the olive-oil/CaF slurry compared with CaF alone. The microwear detail differed between the three lubricants. CONCLUSIONS: This study has shown that enamel wear can be reduced using dry or wet lubricants between opposing teeth that are worn under controlled conditions. Further research is required to clarify their possible clinical applications.