过氧化脲治疗四环素牙的远期疗效

目的评价10％过氧化睬凝胶漂白剂家庭漂白（In-home bleaching）治疗四环素牙的远期临床效果。方法用含10％过氧化脲的凝胶漂白剂。通过可由患者自行取戴的漂白托盘治疗四环素牙，观察其脱色效果及牙色复原等变化情况。结果306例四环素牙患者漂白总满意率为86．6％；随访6个月的201例中，有14．9％于6个月后出现不同程度的颜色复原。1～2年后，仍有较高的满意率。其中30例。每隔2年做1次巩固治疗。随访11年临床效果良好。结论10％过氧化脲凝胶漂白剂治疗四环素牙是有效的方法，着色度越轻治疗效果越好，着色度越重治疗效果越差。同时，漂白治疗具有一定的复原性，坚持巩固治疗。远期效果令人满意。     

漂白处理对树脂充填体边缘微渗漏的影响

目的:评价35%过氧化氢凝胶对树脂充填体边缘微渗漏的影响。方法:选择离体上颌第三磨牙40颗,在颊面制备Ⅴ类洞复合树脂分层充填,光照固化抛光后按处理时间随机分为4组(n=10):A(对照组)、B(10 min)、C(20 min)、D(30min)。将凝胶涂布于充填体表面进行漂白处理后冷热循环500次,再用2%亚甲蓝溶液染色24 h,沿颊舌纵向剖开,体式显微镜观察并记录染料渗入深度。用Kruskal-Wallis法进行数据分析;Mann-Whitney法组间两两比较,检验水准均为α=0.05。结果:不同漂白处理时间对树脂充填体边缘微渗漏的影响有统计学意义(P<0.05);组间比较显示A与C、A与D、B与D、C与D间差异有统计学意义。结论:35%过氧化氢凝胶漂白处理使复合树脂充填体的边缘微渗漏程度增加。     

Efficacy and tolerability of two home bleaching systems having different peroxide delivery

The aim of this study was to investigate tooth whitening efficacy and oral side effects during bleaching with Whitestrips (WS) (6% hydrogen peroxide H(2)O(2) gel) and Vivadent Vivastyle (VS) (10% carbamide peroxide gel). Forty-seven subjects were included in this single blind, randomized, parallel group study. Application of WS was performed twice a day for 30 min. Trays filled with VS were worn for 60 min once a day. Tooth color was evaluated by measuring L*a*b* values before the study and after completion of the bleaching. Treatment tolerability was monitored throughout bleaching with an 8-week follow-up after completion of therapy. After 2 weeks both treatment groups demonstrated significant improvements in tooth color compared to baseline. A shift toward less yellow (-Deltab) and brighter (+DeltaL) tooth color was observed. Deltab amounted to -1.69 +/- 0.38 for WS and -1.20 +/- 0.34 for VS (mean value +/- SE). DeltaL was +1.55 +/- 0.41 for WS and +1.20 +/- 0.37 for VS. There was no significant difference between the two systems. No significant differences between the two bleaching systems were recorded for clinically observed signs or reported symptoms. Gingival irritation was observed in 13%, reported tooth hypersensitivities in 22% and reported gum irritation in 20% of the total study population. At an 8-week follow-up visit no adverse effects were observed. Both WS and VS demonstrated significant and comparable levels of tooth color improvement after 2 weeks. Each treatment caused similar levels of transient oral side effects.     

Investigation of different bleaching conditions on the amount of elutable substances from nano-hybrid composites

Objectives

To analyse the influence of irradiation time, aging before bleaching, and bleaching technique (home bleaching vs. in-office bleaching) on the amount of elutable substances from modern nano-hybrid resin-based composites (RBCs).

Methods

Specimens (n = 5) of three nano-hybrid RBCs (Venus^® Diamond, Tetric EvoCeram^® and Filtek™ Supreme XTE) were irradiated for 5, 10, 20 and 40 s. The degree of conversion (DC) was measured in real-time with Fourier transform infrared spectroscopy (FTIR). Specimens were bleached either directly after irradiation or after aging (1.5 or 6 month in distilled water at 37 °C) with Opalescence^® PF15% for 6 h (simulation of home bleaching) or PF35% for 0.5 h (simulation of in-office bleaching) and incubated in ethanol/water (3:1) at 37 °C for 7 d. The eluates were analyzed by gas chromatography/mass spectrometry. Unbleached specimens at the above mentioned irradiation times were used as controls.

Results

Bleaching increases the amount of elutable substances. This amount is generally stronger influenced by aging than by polymerization time or concentration of the gel. 2-Hydroxyethyl methacrylate was found in amounts up to 334.14 (106.91) μmol/l (Tetric EvoCeram^®, irradiation time 5 s; bleaching with 15% CP) as a destruction product. Diethoyxdimethylsilane was found in all eluates from bleached specimens, but not in the control groups. This substance may be formed by oxidation of 3-methacryloxy-propyltrimethoxysilane, indicating that the bond between inorganic filler and organic matrix might be weakened after bleaching.

Significance

Bleaching gels might alter the physical properties of resin-based composites, especially at low irradiation times and fresh placed restorations.     

几种超分辨率荧光显微技术

传统的光学显微技术受限于瑞利/阿贝准则无法分辨出200 nm以下的结构,而超分辨率荧光显微技术能突破衍射极限对亚细胞结构进行观测.这些超分辨率荧光显微技术大体上可以分为3类:①基于结构光照明的超分辨率成像技术,如受激发射损耗显微技术和饱和结构照明显微术;②基于单分子定位的超分辨率成像技术,如随机光学重构显微术和光激活定位显微术;③基于漂白、闪烁的超分辨率成像技术.本文了上述3类超分辨率荧光显微技术提高成像分辨率的方法及应用,并对其发展趋势进行展望.     

人离体牙树脂修复充填前、后漂白对边缘微渗漏的影响

目的：评价树脂充填前、后漂白对树脂修复体边缘微渗漏的影响。方法收集2015年5月至2016年1月在深圳市福田区中医院口腔科60颗离体上颌中切牙(重度牙周病患者无法保留的患牙),分别行根管治疗后,按患者就诊先后顺序随机分成3组(n=20)：A组直接树脂充填;B组牙漂白术后行树脂修复术;C组树脂充填后行牙漂白术;模拟口腔内环境处理后,在体视显微镜下观测牙漂白术对树脂修复体微渗漏的影响。结果 A组修复体边缘微渗漏率为35%,B组为90%,C组为95%,A组修复体边缘微渗漏率低于B组和C组,差异有统计学意义(P>0.05), B与C组间比较差异无统计学意义(P>0.05)。结论无论树脂充填前或充填后漂白,漂白术均会使复合树脂充填体的边缘微渗漏程度增加。     

Proposal of a flow scheme for the chemical-form-based quantitative analysis of chlorine compounds in pulp for sanitary products and verification of safety

To determine the amounts and chemical forms of chlorine compounds in elemental chlorine-free (ECF) bleached pulp for sanitary products, a chemical-form-based quantitative analysis flow scheme was created. The scheme involves quantitative determination of compounds eluted in elution tests assuming dermal exposure. The results indicated that most of the chlorine compounds in pulp used for sanitary products were insoluble organically bound chlorine and water-soluble chlorides consisting of chloride ions. The total amount of chlorine obtained by analysis of the total chlorine in the pulp products was close to the sum of the amounts of water-soluble chlorides, residual chlorine, chloroacetic acids, and insoluble organically bound chlorine. Therefore, the balance of chlorine measured by the flow scheme was acceptable. Little residual chlorine was detected in the pulp products, suggesting that the chlorine dioxide used for bleaching was almost completely converted into inactive inorganic chlorides and organic chlorine compounds and that these substances do not affect the health risk posed by pulp products. A risk assessment of the detected chloroacetic acid and dichloroacetic acid revealed that there is no concern about the health risk posed by use of these products.     

Bleaching Injection Equipment: Influencing Factors among IDUs who Share

This study investigates factors influencing needle-bleaching intentions and behavior among IDUs who share injection equipment. Analysis of 443 interviews conducted with IDUs who share revealed that intention to bleach and frequency of bleaching were positively associated with attitudes, social norms, perceived behavioral control, and perceived risk of unsafe sharing. Intention was related (positively) to exposure to AIDS-prevention information, whereas frequency of bleaching was associated (negatively) with frequency of intoxication. Exposure to AIDS information may be more effective in creating intention to bleach needles than in stimulating behavior, and noninjection drug use may inhibit bleaching behavior.     

氟斑牙的BEYONDTM冷光漂治疗体会

目的观察BEYONDTM冷光对氟斑牙的漂白效果。方法对30例患者480颗牙齿进行BEYONTM漂白治疗。其中,轻度9例,中度14例,重度7例。对照Vita比色板,观察记录其治疗前后的色阶变化评价其临床疗效。结果治疗后,各组程度的氟斑牙色阶值显著降低(P<0.05)。结论BEYONDTM冷光对氟斑牙有较好的漂白作用。     

离体年轻恒牙脱矿后再矿化及美白效果的实验研究

目的 探讨牙齿美白治疗对脱矿的离体年轻恒牙再矿化及牙色变化的作用.方法 选取和制作24个离体的年轻恒牙标本,用微硬度测量仪(M-400-H1,St,Joseph,MI)测定牙体标本的硬度.牙体的颜色由Shade Vision(X-Bite,Inc.,Grandville,MI)来测定.脱矿处理后,选取的每个标本的牙体硬度控制在170KHN(努氏硬度)左右.24个标本被随机地分成A、B、C 3组(P＞0.05),每组8个标本.C组用美白产品Treswhite进行7次漂白治疗,同时A、B组标本浸泡于人唾液中.然后B、C组用含氟的Crest牙膏进行再矿化处理,而A组用无氟的Crest牙膏进行再矿化处理.每个牙标本的硬度(KHN)和颜色(CIELAB)的数据分别在以下4个阶段采集:原始阶段(BL)、脱矿后(AL)、美白治疗或唾液浸泡后(AB/S)、和矿化治疗后(AR).结果 3组标本的牙硬度在BL、AL和AB/S阶段不存在显著的差异(P＞0.05),在AR阶段,B组、c组标本牙硬度增高而A组牙硬度下降(P＜0.001).脱矿后阶段(AD)各组的牙颜色变化CIELAB数据△E接近8,在AB/S阶段与AD阶段之间,C组的△E值明显高于A、B组(P=0.001),经过再矿化处理,各阶段之间的△E值变小及每组问的△E值不存在显著的差异.结论 美白产品Treswhite对脱矿的离体年轻恒牙的再矿化无不良反应,而对其牙颜色的变化无明显的影响.