使用气流对牙面光洁度影响

目的：探讨洁治和气流（Air-Flow）技术配合使用去除牙面色素、菌斑方法和对牙面光洁度的影响。方法：是光波干涉显微镜观察36颗离体牙在使用Air-Flow技术后牙面粗糙度的变化，并研究磨光糊剂对减轻其粗糙度的作用。结果：气流喷砂和超声洁治一样会使牙面粗糙度显著增加（P〈0.01），进一步磨光可使牙面粗糙度显著下降。结论：临床上使用Air-Flow后，需要用进口抛光糊剂磨光来增加牙面的光洁度。     

多种抛光磨头对烤瓷表面粗糙度的影响

目的：比较釉瓷上釉和不同打磨抛光磨头处理后,烤瓷表面粗糙度的不同,为临床选择抛光方法提供实验依据。方法：制作圆盘状瓷片70片,随机分为7组（n ＝10）。以釉瓷上釉作对照为第1组,第2组至第7组均用松风氧化铝白砂石打磨,第2组打磨后不做处理;第3组打磨后使用松风 Ceramiste 烤瓷抛光套装磨头抛光;第4组在第3组的基础上加用松风Ceramaster 精细烤瓷抛光磨头抛光;第5组打磨后使用德国固美（Komer）烤瓷抛光套装磨头抛光;第6组打磨后使用固美氧化锆抛光磨头抛光;第7组打磨后使用德国 EVE 氧化锆抛光磨头抛光。对瓷片进行轮廓算术平均偏差（Ra）、轮廓的微观不平度十点高度（Rz）、最大轮廓峰高（Rp）的测量,使用 SPSS 16．0统计软件对测量值进行单因素方差分析,并采用扫描电镜对表面形态进行观察。结果：第2、3组的 Ra、Rp 值均大于第1组（P ＜0．05）;第4、5、6、7组的 Ra、Rp 值与第1组差异无显著性（P ＞0．05）;第2、3、4、5组的 Rz 值均大于第1组（P ＜0．05）;第6、7组的 Rz 值与第1组无显著性差异（P ＞0．05）。电镜下观察第6、7组与第1组瓷面平整度相似;第4、5组瓷面较平整,凹坑较少;第2、3组瓷面棱脊、凹坑较多。结论：使用打磨颗粒为微米级超细天然金刚砂的抛光磨头能达到类似上釉的效果。     

复合树脂填料组成对抛光后表面粗糙度的影响

目的：观察复合树脂抛光后组成成分对其表面粗糙度的影响。方法：选择三个厂家不同组成成分和工艺配置的8种复合树脂,制作表面统一基线的试样,用Sof-Lex系列抛光,采用表面粗糙度仪（Surftest SJ-401）检测抛光后树脂的表面粗糙度（Ra值）。结果：（1）同属较大颗粒玻璃填料的复合树脂（AP-X、Quixfil和 TPH3 Spectrum）抛光后表面粗糙度较小粒度和纳米工艺的石英填料复合树脂（Z250、P60、P90和Z350）高;（2）同一厂家的石英混合填料复合树脂与石英纳米树脂抛光后的表面粗糙度相同;（3）复合树脂在垂直于抛光方向上获得的表面粗糙度要比平行于抛光方向的粗糙度高。各树脂Ra值经One-Way ANOVA分析和配对 t检验,P＜0．05。结论：填料的成分和粒度会影响复合树脂抛光后表面的粗糙程度,抛光方向也是重要的影响因素。     

EVALUATION OF THE SURFACE HARDNESS OF COMPOSITE RESINS BEFORE AND AFTER POLISHING AT DIFFERENT TIMES

Purpose:

The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables), Silux Plus (microfilled) and Z100 (minifilled) before and after polishing at different times.

Materials and Methods:

For this purpose, 240 specimens (5mm diameter, 1.4mm high) were prepared. Vickers hardness was determined before and after polishing at different times: immediately, 24h, 7 and 21 days after preparation of the samples. Statistical analysis was performed by ANOVA and Tukey test.

Results:

There was no difference in the hardness of flowable resins, which had lower hardness than the minifilled resin. The minifilled resin showed the highest surface hardness as compared to the other materials (p<0.01). All materials exhibited higher hardness after polishing, being more evident after 7 days.

Conclusion:

It may be concluded that, regardless of the composite resin, surface hardness was considerably increased when polishing was delayed and performed 1 week after preparation of the samples.     

3种义齿基托材料抛光后表面粗糙度的比较研究

目的研究3种义齿基托材料抛光前后的表面粗糙度度。方法选择聚甲基丙烯酸基托树脂（PMMA）、弹性义齿材料和不碎胶等3种义齿基托材料,将材料制成12mm×12mm×2mm的标准试件,每种材料各20个,对试件进行打磨和抛光后,采用表面轮廓测量仪检测材料抛光前后的表面粗糙度,通过扫描电镜对材料表面形貌进行表面观察。结果PMMA、弹性义齿材料和不碎胶抛光后表面粗糙度分别为（0．160±0．018）μm、（0．110±0．011）μm和（0．141±0．017）μ。弹性义齿材料和不碎胶的表面粗糙度低于PMMA（P〈0．05）,表面划痕也少于PMMA。结论弹性义齿材料和不碎胶更能获得抛光效果,表面粗糙度优于PMMA。     

Profile of phenolic compounds in Indonesian rice (Oryza sativa) varieties throughout post-harvest practices

Apart from being a foremost source of calories for a large part of the world’s population, cultivated rice (Oryza sativa) provides beneficial effects for human health through several bioactive compounds, including phenolics. Therefore, to earn this advantage, it is essential to retain the phenolics through appropriate post-harvest practices. In this paper, the profile of 10 individual phenolic compounds contained by rice grains after drying, dehusking and polishing processes were studied. A number of Indonesian rice cultivars from indica and javanica subspecies were acquired from conventional (IR-64, Umbul-umbul and Pandanwangi) and organic farming (Batang Lembang, Pandanwangi, black- and red-pigmented rice) were studied. Additionally, the effect of polishing degree on individual phenolics content in the grain was also evaluated. The level of phenolics decreased, also their relative values dramatically changed throughout a series of post-harvest processes. Moreover, changes on the composition of phenolic acids and its aldehydes in the grain have been described. p-Coumaric acid reflects the greatest differences on the phenolic composition during the course of post-harvest practices that altered from 48% to 8% portion to the total phenolics in paddies and polished grains, respectively. However, phenolics content in black-pigmented rice appeared to be the most persistent in the rice matrix. Since the profile of individual phenolics has also been evaluated on different polishing degrees (70%, 80%, 90% and 100% bran removal), the distribution of these compounds in the whole grain rice was effectively disclosed. These variations in the compositions and quantities of phenolics revealed the effect of post-harvest practices, varietal differences as their distribution in the grain.     

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.     

口腔全瓷修复材料抛光方法研究进展

口腔全瓷材料是目前牙齿修复的主要材料,它具有稳定的色泽、良好的生物相容性以及出色的美观性。全瓷材料的分类目前主要有长石质瓷、玻璃陶瓷和多晶陶瓷。现如今,随着口腔技术不断发展与改进,促使众多研究学者对抛光工具对患者使用效果也引起了高度重视。牙科陶瓷抛光是一种单纯的机械性抛光,亦是一种磨削加工工艺中的精密磨削方式。抛光工具对瓷材料表面的磨削清除是通过磨粒直接完成的,结合剂具有固结磨粒、成形以及较强的支撑作用。抛光是指牙冠经过调磨后,利用工具将表面变成光滑表面的过程。全瓷冠在戴牙时通常需要调磨,该文就口腔全瓷修复体不同抛光工具表面处理方法及其研究进展等相关问题做一综述,希望能够对选择合适的抛光方法带来帮助。     

Polishing for glass ceramics: Which protocol?

PurposeThe execution of adjustments on ceramic restorations is sometimes necessary for either correction of occlusion and/or inadequate contours or esthetical improvements. Clinically, the surfaces undergo weariness through fine grinding diamond burs which remove the superficial glazing layer. Several materials for ceramic polishing have been used in an attempt to reach a satisfactory surface smoothness. The aim of this study was to perform a literature review on different polishing protocols of several dental ceramics.Study selectionThis is a literature review performed through scientific articles published between 2004 and 2012, indexed in MEDLINE, PubMed and Scielo databases. The study selected and analyzed a total of 20 relevant articles that evaluated different types of ceramics, polishing treatment and surface roughness.ResultsAfter an extensive literature review, this study observed: 1 – after the rupture of the glazing layer due to the adjustments of the restorations, the best choice for the polishing of the surface will depend on the type of ceramics used; 2 – glazing procedure provide excellent results regarding to the superficial smoothness; however, if reglazing is impossible, either abrasive rubber cups/points or sandpaper discs followed by the use of diamond polishing pastes results in a satisfactory superficial smoothness; 3 – clinical studies that take into account the behavior of the protocols polishing are scarce and should be encouraged; 4 – the large number of variables influence the final outcome of polishing should be considered.ConclusionsThe necessity in standardization of methodologies to enable a comparison among researches.     

The adverse effects of tungsten carbide grinding on the strength of dental zirconia

ObjectivesThis study investigated the effects of tungsten-carbide grinding on the surface characteristics and mechanical strength of dental 3 mol% yttria-stabilized zirconia (3Y-TZP).MethodsTwo types of tungsten-carbide burs (TC), 6-blade (TC₁) and 8-blade (TC₂) were used to grind 3Y-TZP, in a dental air-turbine handpiece with water-cooling and were also subjected to air-particle abrasion (APA): TC₁ + APA and TC₂ + APA; and rubber polishing (RP): TC₁ + RP and TC₂ + RP; one group received only rubber-polishing RP. The control group received no treatment. Surface characterization was examined by surface roughness (R_a) and atomic force microscopy. Specimens were also observed with scanning electron microscopy (SEM) and X-ray-diffraction (XRD) for microstructure and crystalline phases. A piston-on-three-balls biaxial-flexural strength (BFS) test was performed with 15 samples-per-group and the broken specimen were observed under SEM to investigate the fracture origin pattern. One-way ANOVA, Kruskal–Wallis test and Weibull analysis were performed at α = 0.05.ResultsGroups TC₁ and TC₂ had the lowest mean BFS (p < 0.05) with up to 74 % reduction in strength. APA and RP both significantly increased the mean BFS after tungsten-carbide grinding but was still less than the control (p < 0.05). Compared to the control, the mean BFS was significantly reduced for all groups except for the RP group (p < 0.05). APA and rubber-polishing following TC₂ grinding had significant higher mean BFS than those following TC₁ grinding respectively (p < 0.05). SEM revealed distinct micro-cracks after tungsten-carbide grinding.SignificanceTungsten-carbide burs (6- and 8-blade) are not recommended for zirconia grinding due to the significant reduction of biaxial-flexural strength and observed micro-structural surface and subsurface damage.