不同方法邻面去釉后釉质表面粗糙程度的比较

目的:通过体外pH循环实验,研究不同方法邻面去釉后釉质表面的粗糙度。方法:选择因正畸治疗需要拔除的健康前磨牙30颗,分为3组,每颗牙随机选择1个邻面为实验面,另1个邻面为对照面。3组实验面的邻面去釉方法依次为碳化钨钢车针去釉后Sof-Lex系统抛光、碳化钨钢车针去釉后用10%马来酸配合Sof-Lex系统抛光、碳化钨钢车针去釉后Sof-Lex系统抛光并应用氟保护剂。全部样本进行体外pH循环60d。用粗糙度轮廓仪测量邻面釉质的表面粗糙度,并在扫描电镜下观察。应用SPSS 13.0软件包进行配对t检验和单因素方差分析。结果:3组实验面的表面粗糙度均大于对照面,差异显著(P<0.01);3组实验面之间表面粗糙度的差异无统计学意义(P>0.05)。扫描电镜下,第2、3组实验面的釉质表面较第1组平滑。结论:邻面去釉后,釉质表面粗糙度增加,建议临床操作时局部应用氟化物。     

邻面不同去釉方法对牙釉质的影响

目的:通过体外pH循环实验,找到一种临床效果较好的邻面去釉方法。方法:收集因正畸减数治疗的前磨牙50颗,沿牙体长轴纵向剖开,得到100个样本,随机分为5组。Ⅰ组为片切砂条,Ⅱ组为片切盘,Ⅲ组为片切砂条+抛光+35%磷酸,Ⅳ组为片切盘+抛光+35%磷酸,Ⅴ组为未去釉组。每组样本经过体外pH循环30 d后,采用扫描电镜及显微硬度仪检测,采用SPSS13.0软件包对数据进行统计学分析。结果:①各组的显微硬度值两两比较,Ⅰ组与Ⅱ组、Ⅲ组与Ⅳ组间无显著差异(P>0.05);Ⅰ组与Ⅲ组、Ⅰ组与Ⅳ组、Ⅱ组与Ⅲ组、Ⅱ组与Ⅳ组有高度显著差异(P<0.01);Ⅰ组与Ⅴ组、Ⅱ组与Ⅴ组、Ⅲ组与Ⅴ组、Ⅳ组与Ⅴ组间差异显著(P<0.05)。②肉眼及扫描电镜观察,Ⅲ组及Ⅳ组无明显不同,但均优于其余几组。结论:①去釉盘和去釉砂条的去釉效果无显著不同。②化学抛光组的再矿化效果优于未抛光组及对照组。③邻面去釉后釉质表面的划痕,即使经再矿化也难以恢复。     

不同邻面抛光方法对牙釉质表面粗糙度及表面形貌的影响

目的：评价4种邻面抛光方法对邻面釉质表面粗糙度及显微形貌的影响,为邻面抛光方法的选择提供依据。方法：选择21颗离体牙前磨牙,沿颊舌面中线纵剖后获得邻面釉质试件42枚,再用自凝塑料包埋,暴露邻面釉质,用浮石粉抛光,并超声清洗。将42个试样均分为6组,分别作如下处理：A组空白对照,不做处理;B组：阴性对照,采用标准金刚砂车针切磨触点及其周围釉质,切磨后不抛光;其余4组为实验组,经标准金刚砂车针切磨后分别采用以下方法抛光：C组：极细粒度金刚砂车针抛光;D组：裂钻抛光;E组：矽粒子抛光;F组：彩虹抛光条抛光。之后用粗糙度仪测定釉面粗糙度,并进行扫描电镜观察。结果：标准金刚砂车针切磨后粗糙度大幅度增加（P〈0.05）,釉质表面发生明显条形凹陷性缺损;经4种方法抛光后,釉质表面粗糙度均有显著下降（P〈0.05）,显微形貌均较阴性组光滑,其中矽粒子抛光组可达到较空白对照组更为光滑的表面。结论：实验涉及的4种不同邻面抛光方法均有助于降低釉质切磨区域的表面粗糙度,但抛光效果存在差异;采用矽粒子抛光可完全抵消牙体预备时旋转器械对邻牙邻面的切磨作用,获得最为光滑的釉质表面。     

两种方法去除正畸牙面树脂粘结剂的效果评价

目的 评价两种去除正畸粘结剂及处理釉质表面方法的效果,为临床去除釉质粘结剂提供参考。 方法 选择正畸拔除的前磨牙30个,常规粘结托槽后去除托槽,将其随机分为两组,每组15个,分别使用金钢砂车针和碳钨钻,磨除残留牙体表面粘结剂,记录操作所用时间,用抛光杯抛光后用原子力显微镜测定釉质表面的粗糙度。 结果 金刚砂车针和碳钨钻去除正畸粘结剂操作时间无明显差异, 实验结果显示用碳钨钻磨除粘结剂的釉质表面粗糙度明显小于金钢砂车针, 有明显统计学差异。结论 碳钨钻去除金属托槽粘结剂方法对牙面的影响小于金刚砂车针。     

不同抛光方法对邻面去釉后牙釉质的影响

目的:研究不同抛光方法对离体牙邻面去釉区域釉质脱矿程度的影响.方法:选择20颗离体前磨牙作为实验对象,随机将牙的一个邻面作为对照组,另一邻面作为实验组.对照组邻面去釉后进行物理抛光,实验组邻面去釉后进行化学抛光.所有样本进行体外pH循环60d后,利用激光荧光诊断仪对样本实验区釉质脱矿程度进行定量测定,所得数据采用SPSS10.0软件包进行配对t检验.另选取试样通过扫描电镜观察釉质表面形态结构.结果:对照组釉质脱矿程度较实验组更重,两者差异有高度统计学意义(P＜0.01).扫描电镜观察发现,化学抛光后的釉质表面较物理抛光后更平滑.结论:对邻面去釉后的釉质进行化学抛光较物理抛光可提高釉质表面的光滑程度,降低釉质脱矿的风险.     

Nd: YAG激光照射对邻面去釉后釉质表面的影响

目的:研究不同功率532 nm Nd:YAG激光照射对邻面去釉后釉质表面的影响。方法:体外建立邻面去釉后牙齿样本模型,根据处理方式不同分为对照组、氟制剂组与不同功率激光联合增效剂组,釉质表面形貌通过扫描电子显微镜评估,平板计数法测定样本表面细菌黏附量。结果:扫描电镜下2.2 W激光联合增效剂照射组釉质表面较其余组明显平滑。平板计数结果中除2.8 W及3.0 W激光组外,其余各组釉质表面的细菌黏附量均少于对照组(P<0.05),2.4 W激光组细菌黏附量最小,但与2.2 W激光组组间比较差异无统计意义(P>0.05)。结论:2.2 W Nd:YAG激光联合增效剂照射可明显降低邻面去釉后釉质表面粗糙度及细菌黏附量。     

不同方法去除不同材质正畸托槽及粘接剂的对比实验研究

目的 研究不同方法去除不同材质正畸托槽及残余粘接剂对釉质表面的影响,评价一种适宜高效的去粘接方法,为正畸临床工作提供指导.方法 取因正畸原因拔除的人上颌前磨牙56颗,分别粘接金属或陶瓷托槽,使用2种方法去除正畸托槽后再使用3种不同方法去除残余粘接剂并对牙面抛光.分别检测粘接剂残留指数(ARI),操作时间及牙面粗糙度指数,并使用扫描电镜观察釉质表面微观结构.结果 托槽去除钳及釉质凿组去除托槽后的ARI无显著性差异(P>0.05).金刚砂车针+矽粒子组去除粘接效率最高,Super-Snap抛光碟组次之,矽粒子组最低.矽粒子组处理后釉质表面形貌及粗糙度与天然釉质最接近,Super-Snap抛光碟组次之,金刚砂车针+矽粒子组最差.使用相同方法去除金属托槽和陶瓷托槽无显著性差异(P>0.05).结论 托槽去除钳较釉质凿去除托槽更安全,矽粒子去粘接效果最好但效率最低,Super-Snap抛光碟去粘接效果及效率均处可接受范围,金刚砂车针不适于去粘接.采用相同方法去除不同材质托槽及粘接剂对牙面的影响类似.     

牙齿邻面龋的发展与活动

本文的目的是研究学龄女孩后牙邻面龋的发展及新病变的发生情况。选择年龄11足岁至不满13周岁的学龄女孩,平均年龄为11岁8.6个月。共观察三年以上,每隔一年,作临床及X线片检查。记录X线片上前磨牙及磨牙的邻面情况。根据龋齿严重程度分为Ⅰ(釉质龋)、Ⅱ、Ⅲ或Ⅳ(牙本质龋)Ⅴ(补)、Ⅵ(失)。经过三年以上的时间,一个重要的发现是釉质病变发展不快。第一次检查诊断为釉质病变,第四次检查时仍然如此。当把萌出     

不同正畸托槽粘接剂及釉质抛光方法对牙釉质着色的影响

目的： 比较3种不同托槽粘接剂和4种不同釉质抛光方法对牙釉质颜色改变的影响。方法： 选取120颗正畸需要拔除的前磨牙，随机分为3组，分别使用3种不同正畸托槽粘接剂-化学固化树脂粘接剂、光固化树脂粘接剂和树脂改性玻璃离子粘接剂，每组再随机抽取10颗牙分为4组，分别选择4种不同釉质抛光方法去除粘接剂并抛光牙釉质：碳化钨车针（TC）、碳化钨车针+Sof-Lex抛光杯（TC+SL）、碳化钨车针+One Gloss抛光杯（TC+OG）和碳化钨车针+PoGo抛光杯（TC+PG）。将上述抛光后的牙在咖啡溶液中放置7 d后，用Crystaleye分光光度比色仪进行釉质着色变化值测量。采用SPSS13.0软件包对数据进行双因素方差分析和Bonferroni法分析。结果： 不同抛光方法的组内差异表现为TC组釉质表面颜色变化差异最大，TC+SL组变化值最低，TC+SL和TC+PG组变化值无显著差异（P> 0.05）。不同粘接剂的组间差异表现为树脂改性玻璃离子粘接剂组样本着色变化值最低，化学固化树脂组样本着色变化值最高（P<0.05）。结论： 不同粘接剂类型和釉质抛光方法对釉质表面的着色变化有显著影响。     

残留牙面粘结剂不同去除方法对牙面的影响

目的：评价不同方法去除残留于牙面的托槽粘结剂对牙釉质表面的影响。方法：收集60颗因正畸拔出的健康前磨牙,按不同去除粘结剂方法随机分为3组,每组20颗,分别使用慢速碳钨车针（A组）、超声波洁治（B组）、矽粒子（c组）进行去粘结剂处理,记录每组去除粘结剂所需时间;用万能工具显微镜测量去除粘结剂前后牙釉质厚度改变以计算釉质损失量;体视显微镜下观察釉质表面的粗糙度改变。对操作时间和釉质损失量作方差分析。结果：去粘结剂后釉质损失量排序为超声龈上洁治组〉矽粒子组〉碳钨车针组,三组存在显著差异性（P〈0．05）;去除粘结剂所需时间排序为碳钨车针组〈超声龈上洁治组〈矽粒子组,三组存在显著差异性∽〈0．05）。去粘结剂后体视显微镜观察显示;碳钨车针组镜下釉质表面均匀规则,有少量细微残留物,见少量的细小划痕;超声洁治组镜下釉质表面明显划痕,深浅不一,并有轻重不同的釉质裂纹,牙面上见粘结剂残留较多;矽粒子组划痕较细而浅,数量明显较少。结论：用碳钨车针去除残留牙面粘结剂方法对牙面的影响较小,时间适合临床操作,是临床值得推荐的一种去粘结方法。     

The enamel substrate-characteristics of the enamel surface.

The outer enamel surface is of considerable interest in dentistry as it is the substrate for the acquired pellicle; the pellicle itself is the plaque carrier. In this paper the interface between outer enamel and pellicle is discussed with special emphasis on the outer enamel from a structural and chemical point of view. The outer enamel layer (less than 1 micron from the anatomical surface) is most likely a non-sto?chiometric apatite. The chemical composition is obviously strongly different from the composition of bulk enamel. A model for the structure and atomic composition of surface enamel is presented. The available experimental evidence indicates that at an atomic scale, enamel crystallites have mainly phosphate groups (HPO42-groups) on the solid surface; the liquid adhering Stern layer contains most likely large amounts of calcium ions.     

Ectopic tooth enamel. An SEM study of the structure of enamel in enamel pearls

Eighteen human molars with enamel pearls ranging in diameter from 0.8 to 2.7 mm were sectioned, acid-etched, and processed for SEM observation. In addition to pearl enamel, the specimens contained crown enamel for comparison. All pearls were of the composite type. The enamel layer reached maximal thicknesses of between 0.3 and 0.7 mm opposite the tip of the dentinal cone. The enamel structure was normal, but more variable and irregular than crown enamel. The prism course was often irregular throughout the whole thickness of enamel. Distinct Hunter-Schreger bands were absent. Prisms and interprism were occasionally difficult to identify as separate entities. The packing of crystals seemed to be less tight in pearl enamel. The scarcity of Retzius lines was attributed to the method of preparation. Prism cross-striations with a periodicity ranging between 1.3 and 4.5 microns were frequently encountered. A superficial prism-free zone with a regular 1.7-2.5-microns striation was present in localized regions of many pearls. The formation time of a medium-sized pearl was calculated to be about 11.5 months. A variety of cross-cut prism configurations was observed. Occasional hypoplastic lesions and hypomineralized areas were encountered. In conclusion, pearl enamel possesses most of the structural attributes of crown enamel, but in general its organization seems to be less orderly. Enamel pearls represent developmental disturbances in position and timing more than in structure.     

Quantifying enamel luster

OBJECTIVE: When the pH of the oral cavity drops below 5.5, the hydroxyapatite crystalline lattice is damaged and the tooth surface becomes rough. Consequently, specular reflection is decreased and results, clinically, in a loss of tooth luster. The aim of this study was to develop a digital image capture and processing algorithm to quantify enamel luster. METHODOLOGY: Extracted human teeth (n = 25) containing no restorations and with no clinical evidence of caries were used in this study. The teeth were sectioned longitudinally in a mesial-to-distal orientation to provide experimental and control groups. The experimental group was treated with six consecutive 60-minute exposures to an acidic soft drink, separated by tap water rinses; the control group was similarly treated with just the tap water. Standardized photographs were made before and after application of the treatment or control conditions. Images were converted to eight-bit monochrome digital format. The clinical crown was identified using a standard digital masking technique. Luster in the crown was quantified by determining pixels with luminescence values that were 65% above background. RESULTS: Overall, there was an average 53.6% change in luster in the experimental group, and a nominal 2.10% change in luster in the control group. Analysis of variance revealed a significant loss in luster as measured by this algorithm in the experimental group (p < 0.001), while no significant change in luster was found in the control group. The method reliably identified luster with a repeatability coefficient of 0.992. CONCLUSION: Our digital processing algorithm consistently quantified loss of enamel luster associated with exposure to an acidic beverage. This digit photographic technique may be valuable for evaluating changes in the esthetic chacteristics of teeth when they are exposed to a variety of adverse environments.