光动力疗法防龋对釉质微量元素的影响

目的 将通体发光光纤应用于光动力疗法(PDT)防龋,探讨其对大鼠磨牙牙釉质中Ca、P含量的影响.方法 接种变形链球菌(S.mutans)制备大鼠致龋模型.将80只Wistar大白鼠随机分成5组:17mW(8 mW/cm2)PDT组(A组)、34 mW(15 mW/cm2)PDT组(B组)、68 rnW(30 mW/cm2)PDT组(C组)、20 g/LNaF溶液组(阳性对照组,D组)和生理盐水组(阴性对照组,E组),每组16只.采用650 nm半导体激光器,以质量浓度为40 μg/ml的血卟啉单甲醚为光敏剂,连续进行4周实验.应用电感耦合等离子体发射光谱法检测各组大鼠磨牙牙釉菌中的Ca、P含量.结果 实验后B、C、D组Ca、P含量明显高于A、E组,差异均具有统计学意义(均P＜0.05).A组Ca、P含量实验前后差异均无统计学意义(均P＞0.05);实验后B、C组Ca、P含量分别高于实验前,差异均具有统计学意义(均P＜0.05).A组Ca增量低于D组,差异具有统计学意义(P＜0.05);B、C两组Ca、P增量明显高于D组,差异均具有统计学意义(均P＜0.05);而B、C两组间Ca、P增量差异均无统计学意义(均P＞0.05).结论 在设定的参数范围内,PDT促进牙齿再矿化效果优于20 g/L NaF溶液.采用PDT防龋可增加大鼠磨牙牙釉质中的Ca、P含量,且Ca、P含量与PDT的功率有关.当PDT功率较低时,对釉质再矿化作用不明显;随着PDT功率的增加,Ca、P含量亦增加;当功率增加至一定数值时,两元素含量增量变化不明显,表明PDT可维持牙齿再矿化微环境.     

HMME-PDT对牙骨质片及种植体表面Pg菌斑生物膜的影响

目的 探讨光动力疗法（PDT）对牙骨质片及种植体表面牙龈卟啉单胞菌（Pg）菌斑生物膜的杀灭效果,获得有效杀灭Pg的光敏剂和激光照射的合理剂量.方法 选用Pg标准菌株分别联合经全唾液处理后的无菌牙骨质片和无菌种植体共同培养,建立简易的体外人工牙骨质片和种植体表面细菌附着模型.以血卟啉单甲醚（HMME）为光敏剂,波长630 nm半导体激光为光源,照射牙骨质片表面细菌附着模型60 s后,计算菌落形成单位（CFU）,筛选出最佳激光能量密度（EDL）和HMME剂量,以筛选的合理剂量照射种植体表面细菌附着模型,并用扫描电镜观察PDT对种植体表面菌斑生物膜的影响.结果 当EDL为12J/cm2、HMME质量浓度为25 μg/ml时,PDT可有效杀灭Pg菌斑生物膜（（13.00±5.00） CFU）,且扫描电镜观察到种植体表面无损伤.结论 630nm半导体激光联合HMME介导的光动力疗法（HMME-PDT）对Pg菌斑生物膜有良好的杀灭效果,本实验使用的EDL与HMME剂量较小,有望作为临床治疗剂量.     

光固化树脂表面处理剂对冷光美白牙齿反色效应的影响北大核心

背景:大多研究认为牙齿美白会造成牙釉质表面粗糙,易吸引外源性染色物质再次沾染而形成反色现象,在美白后尝试选用树脂表面处理剂使牙釉质表面光滑,以期降低反色效应。目的:分析光固化树脂表面处理剂Adper Single Bond 2 Adhesive对冷光(氙激光)美白牙齿反色效应的影响。方法:将24颗离体牙涂布体积分数35%的过氧化氢并氙激光照射美白,美白后,其中12颗颊侧涂布光固化树脂表面处理剂Adper Single Bond 2 Adhesive(实验组),另12颗不涂布光固化树脂表面处理剂(对照组),两组组内再分2亚组,分别浸泡于蒸馏水与茶水中进行老化实验,老化实验的第1,3,5,7,14,21,28,35,42天,观察样本色差变化;于美白前、美白后、涂布树脂表面处理后、老化实验的第28天观察样本表面微观结构。结果与结论:①色差变化:实验组样本美白处理前后、涂布树脂表面处理前后及蒸馏水保存前后的色差值无差异(P>0.05);浸泡于蒸馏水后,实验组与对照组色差值无差异;浸泡于茶水后,实验组第1-42天的色差值均小于对照组(P<0.05);②扫描电镜观察:美白处理后的牙釉质表面存在破坏、空洞;涂布树脂表面处理剂后,实验组牙釉质光滑,少有空洞。浸泡于茶水后,实验组表面呈现渐层平滑面,有部分裂痕,片状染色层颜色分解不明显;对照组样本表面有孔洞较大的粗糙面,并清楚可见到茶水留下的斑驳染色层。浸泡于蒸馏水后,所有样本均只见少量块状染色层、孔洞,粗糙程度弱于浸泡于茶水的效果;③结果表明:涂布光固化树脂表面处理剂Adper Single Bond 2 Adhesive能够使冷光美白后的牙釉质表面变得平滑,降低染色物质黏附,起到降低美白后反色效应的作用。     

新型卟啉类光敏剂光动力治疗肝癌的体外实验研究

目的 探讨一种新型卟啉类光敏药物对人肝癌HepG2细胞的光动力学治疗（PDT）作用及其机制.方法 实验分为4组：阴性对照组,PDT组,药物组及药物＋PDT组.采用Bleaching法研究光敏药物的光稳定性;MTT法检测药物对HepG2细胞的PDT杀伤作用;荧光分光光度计检测光敏药物的细胞吸收量;激光共聚焦显微镜检测药物在癌细胞内定位;Hoechst 333342染色检测PDT后HepG2细胞死亡方式.结果 药物对光照比较稳定;单纯光照及单纯光敏药物自身均对HepG2细胞生长无任何影响（P＞0.05）,但药物孵育后行激光照射对HepG2细胞有强烈的PDT杀伤作用（P＜0.05）,IC50值为1.21 μmol/;细胞的药物吸收量呈显著的浓度依赖性,浓度至12.5 μmol/L时吸收量达到饱和;光敏药物分布于HepG2细胞溶酶体内;PDT后HepG2细胞死亡方式主要为凋亡.结论 新型光敏药物能够杀伤人肝癌HepG2细胞,其方式主要通过损伤溶酶体启动继发性的细胞凋亡实现的.     

阿糖胞苷联合光动力疗法对人白血病HL-60细胞作用的研究

目的 探讨阿糖胞苷（Ara-c）在癌光啉（PSD-007）介导的光动力疗法（PDT）杀伤人早幼粒白血病HL-60细胞中的联合作用.方法 实验分为空白对照组、PDT单独作用组（PDT l～4组,为光敏剂剂量（5、7.5μg/ml）和激光能量密度（1.2、2.4 J/cm^2）的两两组合）、Ara-c单独作用组（Ara-c A组和Ara-c B组中Ara-c质量浓度分别为0.3 μg/ml和1.2μg/ml）和联合作用组即上述PDT单独作用组和Ara-c单独作用组的两两组合.所有分组分别按3种时序即P24A时序（PDT作用24h后再加入Ara-c共同作用24h）、A24P时序（Ara-c作用24h后进行PDT再共同作用24h）和PA24时序（PDT作用的同时加入Ara-c再共同作用24h）进行处理.采用CCK-8法检测各组细胞活性,用金氏公式分析联合效应,并用流式细胞术检测细胞周期变化.结果 小剂量PSD-007介导的PDT和Ara-c联合时,3种时序的联合作用均表现为协同效应;而大剂量PSD-007介导的PDT和Ara-c联合时,P24A和A24P 2种时序的联合作用效应为协同或相加,PA24时序则主要为相加或拮抗.流式细胞仪检测细胞周期变化结果显示,Ara-c和PSD介导的PDT均能引起细胞周期G0/G1期阻滞.结论 Ara-c与PSD-007介导的PDT联合作用对HL-60细胞的杀伤有协同作用,其协同作用与剂量和作用时序相关,小剂量比大剂量协同效果明显,且Ara-c和PDT间隔24h作用比2者同时作用于该细胞的协同效果明显.     

树脂渗透修复脱矿牙齿

背景：树脂渗透技术是一种治疗早期龋的新方法,为评估其治疗效果,与传统再矿化治疗方法进行比较。 目的：比较树脂渗透技术与氟化物再矿化治疗拮抗牙体组织脱矿的效果。 方法：将35颗牛牙样本的釉质表面各制备出3个相同大小的窗区,分别设为渗透区、氟化钠区、空白区,将样本制备为脱矿模型,渗透区行树脂渗透处理(Icon®),氟化钠区每天以0.1%NaF溶液涂布连续7 d(即氟化物再矿化治疗),空白区不作处理;将样本自底部垂直向表面二等分,一份设为脱矿组再次脱矿,一份设为对照组置于去离子水中保存,观察脱矿组与对照组相对应窗区脱矿深度的进展。 结果与结论：牛牙样本渗透区、氟化钠区脱矿深度的进展均小于空白区(P < 0.05),且渗透区脱矿深度的进展小于氟化钠区(P < 0.05)。提示树脂渗透技术和氟化物再矿化治疗均可抑制牙体组织进一步脱矿,树脂渗透技术拮抗脱矿效果可能更佳。     

光动力疗法的抗肿瘤机制及光敏剂的研究进展

光动力疗法（PDT）是利用光动力效应对疾病进行诊断与治疗的一种非侵袭性技术,已被用于临床头颈部、乳腺、肺、前列腺及皮肤等部位肿瘤的治疗.与传统治疗方法相比,PDT具有创伤小、毒性低、选择性好、适用范围广及不易产生耐药等优势,因而受到肿瘤治疗领域的广泛关注.PDT的抗肿瘤机制复杂,光敏剂是发挥其光动力学效应的关键因素之一,提高光敏剂的靶向输送和携氧能力是改善光动力疗效的重要途径.对PDT的抗肿瘤机制及光敏剂的研究进展进行综述.     

光动力疗法治疗变应性鼻炎的实验性研究

目的 初步研究光动力疗法（PDT）对实验性变应性鼻炎（AR）的治疗作用.方法 随机将18只新西兰兔均分为实验组A、阴性对照组B、空白对照组C共3组,采用卵清蛋白（OVA）致敏A、B2组兔制作动物AR模型,A组予以PDT治疗,B、C2组予以自然光处理,观察治疗前后症状及体征的变化,在光镜和透射电镜下观察鼻黏膜的变化.结果 与B组相比,A组兔经PDT治疗后,与AR相关症状和体征明显改善,光镜及透射电镜观察显示,炎性细胞明显减少,黏膜结构逐渐恢复,21 d后,A组与C组相比喷嚏次数、抓鼻次数及鼻分泌量差异无统计学意义（P＞0.05）,光镜及透射电镜下观察黏膜结构表现基本相似.结论 PDT对实验性AR有一定的治疗作用,为PDT用于AR定点治疗的临床应用提供了实验基础.     

含氟纳米氟磷灰石糊剂修复人工釉质缺损

背景：纳米氟磷灰石糊剂涂敷法可在人牙齿表面生长出类似牙釉质的柱状晶体。 目的：观察1 mg/L人体安全浓度的氟离子对纳米氟磷灰石糊剂修复人工釉质缺损的影响。 方法：将人工早期釉质缺损样本随机分成两组,分别在样本表面涂敷添加含氟的纳米氟磷灰石糊剂(实验组)与不加氟的纳米氟磷灰石糊剂(对照组),置于37 ℃水浴孵箱中修复。反应前后对牙齿表面行扫描电镜观察,晶体结构分析,化学成分鉴定和韦氏显微硬度测试。 结果与结论：经处理后,两组样品表面都可见有一层与牙釉质化学组成和晶体结构类似的晶体生成,但实验组牙釉质样品表面结晶度、韦氏显微硬度明显高于对照组样品(P < 0.05),且实验组牙釉质样品表面更光滑。结果表明,人体安全浓度含氟纳米氟磷灰石糊剂可明显提高人工釉质龋显微硬度、结晶度和表面光滑度。     

离体人氟斑牙脱矿与再矿化的研究

通过研究不同严重程度人氟斑牙在体外经人工龋脱矿实验及再矿化处理前后,釉质表面显微硬度值的变化,探讨氟斑牙的严重程度与脱矿再矿化的关系。结果发现:脱矿后氟斑牙的表面显微硬度损失百分比(%SMHD)为TFI4(18.92±1.31)TFI3(20.50±1.32)TFI2(25.08±1.69)TFI1(27.77±1.79)TFI0(30.70±1.35),(P0.05),轻度氟斑牙TFI1(27.77±1.79)与对照组正常牙TFI0(30.70±1.35)没有显著统计学差异。再矿化处理后氟斑牙的表面显微硬度恢复的百分比(%SMHR)为TFI1(55.17±4.03)TFI0(53.97±4.96)TFI2(49.17±3.11)TFI3(44.85±3.21)TFI4(36.51±2.95)(P0.05);中重度氟斑牙的抗龋性显著高于轻度氟斑牙及正常牙,轻度氟斑牙再矿化的效果明显好于中重度氟斑牙,同时也比正常牙稍好。值得临床注意。     

Quantitative light-induced fluorescence: a potential tool for general dental assessment

Current dental diagnostic methods can detect caries but cannot quantify the mineral status of a lesion. Quantitative light-induced fluorescence (QLF) measures the percentage of fluorescence change of demineralized enamel with respect to surrounding sound enamel, and relates it directly to the amount of mineral lost during demineralization. Development of caries-like lesions and subsequent remineralization of the lesions were monitored by QLF. The results showed that the percentage of fluorescence change (Delta Q) increased linearly with the demineralization time and decreased with increased remineralization time. Stained teeth were whitened with a bleaching agent and the change in stain intensity (Delta E) was quantified using QLF. The results showed that Delta E decreased linearly as the tooth regained its natural color. Factors that might affect the use of QLF to detect and quantify caries were also examined. It was concluded that QLF could be used to detect and longitudinally monitor the progression or remineralization of incipient caries, however lesion detection may be limited by the presence of saliva or plaque and enhanced by staining. The change in shade of discolored teeth by whitening agents could be quantitatively measured by QLF.     

无创渗透树脂材料修复早期乳牙邻面龋

背景：乳牙早期邻面龋因解剖位置的原因菌斑不易去除,常规再矿化治疗疗效不佳。 目的：观察无创渗透树脂技术治疗乳牙早期邻面龋的临床疗效。 方法：选择乳牙邻面早期龋的患牙120颗,随机分为渗透树脂组和流动树脂组,每组60颗,分别应用渗透树脂和流动树脂进行治疗,治疗后1年随访,对患者邻面龋的牙体形态、去除釉质脱矿造成的白垩色斑和色泽稳定性、继发龋和治疗成功率方面进行临床评价。 结果与结论：两组患者在充填治疗后1年的疗效检查结果中发现,渗透树脂组邻面龋的牙体形态、去除釉质脱矿造成的白垩色斑以及色泽稳定性、继发龋方面均好于流动树脂组。渗透树脂组的治疗成功率96.7%远高于流动树脂组的76.7%,差异有显著性意义(P < 0.05)。无创渗透树脂材料是目前阻断龋病发展简便高效的方法。     

Preparation of a hydroxyapatite and hydrogen peroxide composite for tooth whitening

Hydroxyapatite (HA)/Hydrogen Peroxide (H(2)O(2)) solutions was prepared for a tooth whitening application. HA powder was immersed in the 100, 1000 and 10,000 ppm of the H(2)O(2) solutions. The HA/H(2)O(2), HA and H(2)O(2) solutions were applied to HA discs and extracted teeth for weight and whiteness change evaluation. After 24 hours, each HA disc was measured for the weight changes and each tooth was measured for the whitening changes (L(*)) using a Spectro Color Meter. The topology of the teeth surfaces were also observed using Scanning Electron Microscope (SEM). The weight of the HA disc applied with H(2)O(2) at all concentrations was lower than that applied with HA and HA/H(2)O(2) solutions. The whiteness of the teeth treated with HA/H(2)O(2) were higher than that treated with HA and H(2)O(2) only solutions. The whiteness change of the teeth treated with the HA/H(2)O(2) (10,000 ppm) showed the highest value in all solutions at L(*)=4.98+/-0.90 (p<0.05). In the SEM observation, the teeth surface treated with the H(2)O(2) showed rough and destructive holes on the enamel surface. However, the teeth surface treated with the HA/H(2)O(2) show smooth enamel surface due to covering of the destructive holes with HA powder.     

In vitro detection and quantification of enamel and root caries using infrared photothermal radiometry and modulated luminescence

Artificially created demineralized and remineralized carious lesions on the root and enamel of human teeth were examined by photothermal radiometry (PTR) and modulated luminescence (LUM). Fourteen extracted human teeth were used and a lesion was created on a 1 mmx4 mm rectangular window, spanning root to enamel, using a lactic acid-based acidified gel to demineralize the tooth surface. The lesion was then exposed to a remineralization solution. Each sample was examined with PTR/LUM on the root and enamel before and after treatment at times from 1 to 10 (5 on root) days of demineralization and 2 to 10 days of remineralization. Ten-day (5 on root) demineralized samples were remineralized. After completing all the experiments, transverse microradiography (TMR) analysis was performed to compare and correlate the PTR/LUM signals to the depth of lesions and mineral losses. The PTR and LUM amplitudes and phases showed gradual and consistent changes with treatment time. In this study, TMR showed good correlation coefficients with PTR and LUM. It was also found that the length of the treatment time did not correlate very well to any technique, PTR/LUM or TMR, which implies a significant degree of inhomogeneity of the demireralization and remineralization rates in each and every tooth.     

酪蛋白磷酸多肽/无定形磷酸钙复合物与氟化钠预防正畸托槽周围的牙釉质脱矿

BACKGROUND: In clinical practice, both casein phosphopeptides/amorphous calcium phosphate compound and fluoride can effectively prevent the occurrence of enamel demineralization and caries. OBJECTIVE: To investigate the preventive effects of casein phosphopeptides/amorphous calcium phosphate compound and fluoride on enamel demineralization in the orthodontic treatment, so as to seek a remineralization agent with good effect. METHODS: Totally 40 human in vitro teeth which had been well bonded to brackets were randomly divided into four groups: control group (the surface was not coated with any substance), GC tooth mousse group (the surface was coated with casein phosphopeptides/amorphous calcium phosphate compound), duraphat group (the surface was coated with fluoride) and combined group (the surface was coated with casein phosphopeptides /amorphous calcium phosphate compound and fluoride). The enamel surface porosity was observed by scanning electron microscopy after the successive 14-day demineralization-remineralization experiments in these four groups. The change value of microhardness was measured before and after the experiment in each group. RESULTS AND CONCLUSION: There was obvious enamel demineralization in the control group, but not in the other three groups. The change value of microhardness in GC tooth mousse, duraphat and combined groups was lower than that in the control group (P < 0.05), and there was no significant difference between GC tooth mousse, duraphat and combined groups. These results demonstrate that fluoride, casein phosphopeptides/amorphous calcium phosphate compound and their combination can prevent enamel demineralization, promote remineralization; however, their combination does not improve the effect of preventing enamel demineralization.         

Ex vivo detection and characterization of early dental caries by optical coherence tomography and Raman spectroscopy

Early dental caries detection will facilitate implementation of nonsurgical methods for arresting caries progression and promoting tooth remineralization. We present a method that combines optical coherence tomography (OCT) and Raman spectroscopy to provide morphological information and biochemical specificity for detecting and characterizing incipient carious lesions found in extracted human teeth. OCT imaging of tooth samples demonstrated increased light backscattering intensity at sites of carious lesions as compared to the sound enamel. The observed lesion depth on an OCT image was approximately 290 microm matching those previously documented for incipient caries. Using Raman microspectroscopy and fiber-optic-based Raman spectroscopy to characterize the caries further, spectral changes were observed in PO4 (3-) vibrations arising from hydroxyapatite of mineralized tooth tissue. Examination of various ratios of PO4 (3-) nu2, nu3, nu4 vibrations against the nu1 vibration showed consistent increases in carious lesions compared to sound enamel. The changes were attributed to demineralization-induced alterations of enamel crystallite morphology and/or orientation. OCT imaging is useful for screening carious sites and determining lesion depth, with Raman spectroscopy providing biochemical confirmation of caries. The combination has potential for development into a new fiber-optic diagnostic tool enabling dentists to identify early caries lesions with greater sensitivity and specificity.     

Photofrin光动力联合化疗对食管癌细胞株Eca-109增殖的影响

目的研究Photofrin光动力联合氟尿嘧啶和顺铂化疗药物对食管癌细胞株Eca-109增殖的抑制作用。方法将食管癌细胞株Eca-109分为6组，A：对照组，B：化疗组，C：化疗＋高剂量光敏剂治疗组，D：化疗＋低剂量光敏剂治疗组，E：高剂量光敏剂治疗组，F：低剂量光敏剂治疗组。种板孵育24h后，采用台盼蓝染色法检测肿瘤细胞的存活率；于化疗组加入化疗药（5-Fu＋DDP）作用12h，再按实验分组加入光敏剂血卟啉衍生物（HPD）低剂量或高剂量，4h后行630nm激光照射，光能量密度30J／cm^2，照光后继续培育24h，开始行MTT法检测食管癌细胞增殖的抑制率。结果除了低剂量光敏剂＋化疗组同高剂量光敏剂组差异不显著外．其余相互间差异均有统计学意义，高剂量光敏剂＋化疗组细胞抑制率较高，低剂量光敏剂组抑制率较低。结论在特定光源状态下,一定的光敏剂、光照能量密度、孵育时间，光敏剂孵育浓度是人食管癌细胞Eca-109体外光动力效应的主要影响因素。两种不同的HPD孵育浓度下细胞抑制率有显著性差异。相同光照能量密度及孵育时间下，孵育浓度越高，其杀伤效应越强。光动力与化疗联合对食管癌细胞的杀伤力提高，光动力与化疗有协同作用。     

Scanning microscopy of platypus teeth

Summary Anorganic unerupted developing teeth and airdired erupted teeth of the platypus (Ornithorhynchus anatinus) were examined in a scanning electron microscope and in a tandem scanning reflected light microscope. Typically mammalian developing fronts of enamel and dentine were identified in the anorganic unerupted specimens. The developing teeth were particularly small and fragile and the enamel elusive and difficult to examine in the normal way for morphological detail. Prepared fractured surfaces of unerupted specimens revealed preferentially oriented crystallite groups in the enamel generally perpendicular to the developing front and a highly globular, mineralized pattern in the dentine with fine diameter, sparsely distributed dentinal tubules.Although optically homogeneous, the enamel of both developing and mature teeth displayed well-defined incremental lines, radial clefts, crystallite domains of variable size and outline, and fine tubules when examined by high contrast, back-scattered electron imaging. The enamel is prismatic only in part; well-formed, regular prisms not being a primary feature of platypus enamel. This can be related to the variability inherent in the developing surface and the thinness of the enamel layer. No surface was found which could be confidently identified as cementum; those developing surfaces not covered by enamel displaying small calcospherites which elsewhere marked the outer aspect of the dentine.     

Properties of tooth enamel in great apes

A comparative study has been made of human and great ape molar tooth enamel. Nanoindentation techniques are used to map profiles of elastic modulus and hardness across sections from the enamel–dentin junction to the outer tooth surface. The measured data profiles overlap between species, suggesting a degree of commonality in material properties. Using established deformation and fracture relations, critical loads to produce function-threatening damage in the enamel of each species are calculated for characteristic tooth sizes and enamel thicknesses. The results suggest that differences in load-bearing capacity of molar teeth in primates are less a function of underlying material properties than of morphology.