测量甲硝唑根管消毒控释系统药物释放度方法的评价

目的 对测量甲硝唑根管消毒控释系统药物释放度的方法进行评价,方法 作体外释放实验,离体牙根周释药实验及自行设计的体内释药实验,求１,３,７,１０天的甲硝只释放度,进行统计学分析,结果：体外与离体牙,体内实验的累积药物百分率在不同的时间均有极明显显著性差异（Ｐ〈０．０１）;离体牙与体内实验的累积释药百分率同无显著性差异（Ｐ〉０．０５）。结论：利用离体牙,将释放介质生理盐水控制在３７℃,ｐＨ７．４测定     

甲硝唑缓释牙胶尖的制备及体外释放实验

目的:研制一种用于根管消毒的甲硝唑缓释系统,测定其体外持续释放有效药物浓度的时间。方法:选择牙胶尖为载体,吸附甲硝唑等制备成药尖,聚乙二醇-1500与醋酸纤维素分别按不同比例混合作缓释膜,制成4组甲硝唑缓释牙胶尖(SRDGM),根据4组缓释剂的体外释放度及相应参数,选择释放甲硝唑有效药物浓度时间最长的一组作为实验用的缓释剂。选8颗单根管离体牙,SRDGM作根管消毒剂,紫外分光光度法测定体外释放度。结果:SRDGM含甲硝唑2013μg,24h释出全部药量的68.24%。SRDGM在离体牙根管内持续释放有效药物浓度达10d以上,第10天释出药物浓度33.13μg/ml,超过甲硝唑的最低抑菌浓度。结论:本研究研制的SRDGM可以载送药物,并控制释放;能在根管内维持一定时间的有效药物浓度达10d以上,防止根管再感染。     

根管消毒药物控释系统的制备及体外释放研究

研制了一种高分子材料为载体的根管消毒药物控释系统,并进行了体外控制释放研究,该系统能在10d时间内稳定释放消毒药物,具有应用前景。     

牙周炎缓释药管的研制和临床应用

作者研制设计20%盐酸四环素控释药管,用于治疗牙周炎,进行了体外实验和临床疗效分析。采用微孔聚丙烯中空纤维为载体,它的内径为270μ,管壁上有栅栏状微孔,药物能缓慢释放。经紫外分光光度计测定,24小时药物释放量为140±3.10μg/ml/cm,48小时4.9±1.7μg/ml/cm,72小时为1.3±0.3μg/ml/cm。四环素对产黑色素类杆菌群的MIC为≤0.39μg/ml,对核梭杆菌的MIC0.2和0.39μg/ml,因此,1cm长药管足以达到有效抑菌浓度。临床治疗100例牙周脓肿,总有效率92%,与对照组相比有显著性差异(P<0.001)。因此,四环素控释药管的局部应用,为牙周炎治疗开辟了新的途径,是药物剂型学的新发展,值得研究和推广。     

新型药物控释根充尖用于牙髓尖周病治疗的可行性研究

在研制根管消毒药控释系统的基础上，制备一种成形根管充填材料，命名为药折控释根充尖，抑菌实验结果提示其整体型，贮库型以及与牙胶糊剂、酚醛树脂液协同使用时均可产生抑菌作用，在大中的根充尖横断面亦有明显抑菌效果，离体牙根尖孔渗出药物的高效液相色谱分析提示，其有效浓度释药时间可持续２周以上，研究证实：药物控释根充尖可望作为一种新型的根充材料用于牙髓病、尖周病的治疗。     

复方甲硝唑缓释药条的研究

以甲硝唑和螺旋霉素为主剂，经抑菌浓度实验和缓释材料的筛选，研制成复方甲硝唑缓释药条，并进行了药物浓度的测定和体外溶出度实验。结果显示：复方甲硝唑缓释药条的抑菌平均直径明显大于甲硝唑和螺旋霉素各单方的缓释药条，其临床效果也以复方缓释药条最佳。     

甲硝唑口腔膜的药物释放评价

采用家兔阴道给药的体内实验和离体肠管的体外测定方法，从不同侧面评价了甲硝唑口腔膜的药物释放情况和时效关系，结果表明：甲硝唑口腔膜１５ｍｉｎ就释放药物达有效浓度，３０ｍｉｎ时药量透时折半，药效可维持２ｈ。     

环丙沙星纱条在上颌骨囊肿摘除术中的应用

上颌骨囊肿摘除术后按常规需用碘仿(iodoform)纱条填塞术腔,但碘仿有不适的臭味,并且市场上缺少碘仿货源。为解决临床需要,我们对药物纱条进行了筛选,淘汰了具有耳毒性的氨基糖甙类抗生素;毒性大的氯霉素;有过敏反应的磺胺类药物;最后选用对革兰氏阳性(G~+)及革兰氏阴性(G~-)致病菌有抗菌活性广谱、高效抗菌新药环丙沙星(ciprdfloxacin)作为纱条的主药以替代碘仿,并与碘仿作了抑菌试验对比,根据药物浓度筛选结果配制环丙沙星溶液100ml。(环丙沙星0.4g、西黄 胶 0.2g、0.9％生理盐水100ml,浸润30g纱条,经60℃烘干后加入灭菌凡土林70g;使每块纱条合主药环丙沙星10mg/g。     

平阳霉素白蛋白微球的制备及其体外释药的实验研究

目的　制备平阳霉素白蛋白微球(PYM-AMS),用于治疗动静脉血管畸形。方法　采用乳化热固化法,在 140℃制备出PYM-AMS,并考察其理化性质:通过超声测定强度,激光散射粒径分析仪测定粒径大小,紫外分光光度法测定载药率、包封率和体外模拟累积释放度。把制备好的PYM-AMS分装后,经60Co辐照灭菌。并通过放置于冰箱(3~5℃)、室温(15~25℃)和37℃,RH75%条件下放置3月,考察其稳定性。结果　制备的PYM-AMS平均粒径为139·422μm,56~251μm的微球约占总数的80%,载药率为26·47%,包封率为84·3%;5 h内药物快速释放,之后进入缓慢过程,24 h累积释放率为88·65%,t50为1·5 h;分装后,经60Co辐照灭菌;性质稳定,经5号、6号药典筛筛分后,可获得125~180μm的微球。结论　制备的PYM-AMS载药量高,具有缓释效果,能够达到治疗动静脉畸形的要求。     

Ca(OH)2和Hoshino制剂对猪牙乳头细胞增殖的影响

目的研究Ca(OH)₂和Hoshino制剂（甲硝唑、环丙沙星、米诺环素混合制剂）对体外培养的猪牙乳头细胞（procine dental papilla cells,pDPCs)增殖的影响,探讨临床使用牙髓血管再生治疗时根管消毒药物的选择。方法将第4代pDPCs分别在含不同浓度Ca(OH)₂（10%、1%、0.1%）和Hoshino制剂（0.5%、0.1%、0.05%）的培养基中培养,采用CCK-8法检测2种药物对细胞增殖活性的影响,采用SPSS19.0软件包对实验结果进行统计学分析。结果Ca(OH)₂对pDPCs细胞的增殖影响呈波动状,细胞培养9 d时,各组浓度Ca(OH)₂对细胞增殖无影响;Hoshino制剂可抑制pDPCs的增殖。结论实验中各浓度组Ca(OH)₂ 制剂对pDPCs 细胞的增殖无影响,而Hoshino制剂可抑制pDPCs 细胞的增殖。     

In vitro antimicrobial susceptibility to combinations of drugs of bacteria from carious and endodontic lesions of human deciduous teeth

The purpose of this study was to clarify the antibacterial efficacy of mixed antibacterial drugs on bacteria of carious and endodontic lesions of human deciduous teeth in vitro . The antibacterial drugs used in this study were mixtures of ciprofloxacin, metronidazole, plus a third antibiotic: amoxicillin, cefaclor, cefroxadine, fosfomycin or rokitamycin. Samples taken from carious dentin (17 cases) and infected pulpal tissues (14 cases) were cultured on control plates and plates containing the mixed drugs. No bacteria were recovered in the presence of any combination of the mixture of the drugs (100μg each/ml), and the bacterial growth occurred on control plates (10¹ to 10⁷ colony-forming units), indicating that the mixed drugs inhibit the growth of bacteria in the samples. When carious and endodontic lesions on split surfaces of freshly extracted teeth were covered overnight with α-tricalcium phosphate cement containing a mixture of ciprofloxacin, metronidazole and cefaclor (1% each; 5 cases), no bacteria were recovered from the lesions. No bacteria were recovered from carious and endodontic lesions when these lesions were immersed in a solution of the mixture (200 μg each/ml; 5 cases). These findings indicate that carious and endodontic lesions can be sterilized by the mixed drugs in situ .     

Influence of gutta-percha points on the filling of simulated lateral canals

The aim of this study was to investigate, in vitro, the percentage of filling of simulated lateral canals in teeth obturated with TP medium and standardized gutta-percha points. Twenty human mandibular canines were prepared with LA Axxess (SybronEndo) and K3 Endo rotary system (SybronEndo) up to a #50 file, according to the Free Tip Preparation Technique. During instrumentation, the root canals were alternately irrigated with 1% sodium hypochlorite and 17% EDTA. Six artificial lateral canals were prepared at the apical third of each tooth. Then, the teeth were assigned to two groups (n=10): Group 1 - filled with TP medium master gutta-percha points (Dentsply, Mailleffer); Group 2 - filled with standardized master gutta-percha points (Dentsply, Mailleffer). Root canal filling was complemented with AH Plus sealer (Dentsply, Mailleffer) and accessory gutta-percha points (Dentsply, Mailleffer), according to the classic technique. The teeth were radiographed and the images obtained were digitized. Linear measurements of the percentage of filling of the artificial lateral canals in each group were accomplished on the Image Tool 2.02 software. Statistical analysis of the data using Mann-Whitney U non-parametric test evidenced significant difference (p<0.01) between the experimental groups. The group obturated with TP medium points yielded higher percentage of filling of the lateral canals. It may be concluded that the use of master gutta-percha points with larger taper resulted in better filling of the simulated lateral canals, as compared to the use of standardized master gutta-percha points.     

GuttaFlow结合不同锥度牙胶尖充填质量的体外评价

目的：对常温牙胶充填系统GuttaFlow采用不同锥度牙胶尖充填质量进行体外评价。方法：将40颗上颌切牙经K3预备至0.06锥度40号后,随机分为0.02锥度组和0.06锥度组,分别用多根0.02锥度牙胶尖和单根0.06锥度牙胶尖,结合GuttaFlow进行根管充填。使用RVG摄像系统,对每颗牙颊舌向、近远中向进行X光投照后评分。包埋冠部,自根尖向冠方垂直于牙体长轴每隔1mm制备横截面切片。体视显微镜下观察切片中空隙的分布与面积。结果：0.02锥度组近远中向及双向整体评分、空隙的发生率及距根尖5～8mm水平的空隙横截面数均显著高于0.06锥度组;其他观察指标两组之间无显著性差异。近远中向评分与空隙面积百分比显著相关。结论：使用GuttaFlow系统进行根充时,推荐采用与根管预备锥度相一致的主牙胶尖,并且根管上段可适当增加辅尖。     

Apical seal of root canals with gutta-percha points with calcium hydroxide

The objective of this research was to determine if gutta-percha points with calcium hydroxide [Ca(OH)2] improve the apical seal after root canal filling and if the master point does it alone. Human single recently extracted teeth were biomechanically prepared and the root canals filled by the lateral condensation technique with ZOE and gutta-percha points, with or without calcium hydroxide. The teeth were placed into a 2% methylene blue solution in a vacuum environment for 24 h after which they were processed for stereomicroscope evaluation. Better results were observed with the teeth filled with gutta-percha points with calcium hydroxide (p=0.01). We conclude that these new points make a better apical seal and that these results can also be obtained with the calcium hydroxide master point associated with regular ones (p=0.05).     

Attachment of human periodontal ligament fibroblasts to 3 different root-end filling materials: Scanning electron microscope observation

OBJECTIVE: The attachment behavior of the human periodontal ligament (PDL) fibroblasts to root-end filling materials (amalgam and Super-EBA) was compared in vitro to gutta-percha by means of scanning electron microscope. STUDY DESIGN: Amalgam and Super-EBA were placed in a prepared cavity of root slices of freshly extracted human teeth and evaluated freshly prepared. Root slices of teeth with cold-burnished gutta-percha filling with AH26 sealer were used for comparison. The root slices were placed in tissue culture cluster, and 1 mL of cell suspension was added carefully over the root slice. They were incubated at 37 degrees C and 100% humidity for 4, 24, and 72 hours. RESULTS: Results showed that the cold-burnished gutta-percha provides a better substrate than amalgam and Super-EBA for cell growth and attachment. Amalgam was the most toxic material, showing early manifestation of cell injury. CONCLUSION: It was concluded that the composition and surface texture of the substrate have an influence on the morphology and the attachment of the PDL fibroblasts. It is suggested that cell attachment and morphology might reflect the biocompatibility of the substratum.     

Serum and crevicular fluid concentrations after a single oral dose of metronidazole

Previous studies have shown that metronidazole is an effective chemotherapeutic agent in the treatment of certain types of periodontal disease. The purpose of this study was to assess, over 18 hours, the concentration of the drug in serum and gingival crevicular fluid after a single oral dose. Six female volunteers with gingivitis created by cessation of brushing for 2 weeks, took 250 mg of metronidazole orally. Micropipettes were used to collect 20 microliters of serum and 4 to 5 microliters of gingival fluid hourly for 8 hours, and at the 12th and 18th hours. Samples were assayed with a high pressure liquid chromatograph. Mean drug levels in serum closely matched those reported by Stephen et al. (Br Dent J 7: 313, 1966) with polography. Mean serum drug levels peaked at 6.09 micrograms/ml at the 2nd hour, and mean gingival crevicular fluid drug levels peaked at 3.62 micrograms/ml at the 2nd and 7th hours. The drug was detectable in both fluids for up to 18 hours. Mean serum concentrations remained greater than mean gingival fluid concentrations at all time intervals, though the differences were not significant (P less than 0.05) as determined by a Hoteling's T2 test. Using reported minimal inhibitory concentration values of metronidazole for various periodontopathogens, it was concluded that a single oral dose of metronidazole will deliver potentially inhibitory levels of the drug to the periodontium in serum and in gingival crevicular fluid.     

Fracture resistance of roots endodontically treated with a new resin filling material

BACKGROUND: The authors evaluated the fracture resistance of endodontically treated teeth filled with either gutta-percha or a new resin-based obturation material. METHODS: The authors prepared and randomly divided 80 single-canal extracted teeth into five groups: lateral and vertical condensation with gutta-percha, lateral and vertical condensation with the new resin-based obturation material, and a control group with no filling material. The specimens were stored in 100 percent humidity for two weeks, mounted in polyester resin and loaded to failure. RESULTS: The authors found statistically significant differences among the experimental groups (P < .05). The groups with the new material displayed higher mean fracture loads and the gutta-percha groups lower mean fracture load values than the control unfilled group. However, the differences were not significant. The groups with the new material displayed significantly higher mean fracture loads than gutta-percha groups independent of the filling technique used. CONCLUSIONS: Filling the canals with the new resin-based obturation material increased the in vitro resistance to fracture of endodontically treated single-canal extracted teeth when compared with standard gutta-percha techniques. CLINICAL IMPLICATIONS; If other properties of the new resin-based obturation material compare favorably with those of gutta-percha for filling the root canal, it should be considered as a replacement for gutta-percha, as the results of this study indicate that it could provide enhanced resistance to tooth fracture.     

Vertical root fractures in curved roots under simulated clinical conditions

The purpose of this study was to determine the incidence of vertical root fractures in the mesial roots of extracted human mandibular molars that were endodontically prepared by hand or ultrasonic instrumentation and obturated with laterally condensed gutta-percha and sealer using finger and hand spreaders. One-hundred twenty mesiofacial canals were prepared by hand or ultrasonic instrumentation. After placing the teeth in a simulated alveolus, they were obturated by laterally condensing gutta-percha and sealer with B-finger or D11T hand spreaders. Teeth were obturated using forces in the range of 1 to 3 kg or 4.5 to 7.5 kg. Three teeth obturated with the D11T hand spreader using 7.0 to 7.3 kg of force demonstrated vertical root fractures. The results suggest that in vitro the range of forces reported as most commonly used by endodontists to laterally condense gutta-percha (1.0 to 3.0 kg) and those of a higher magnitude up to 4.9 kg are safe and will not result in vertical root fractures of mesial roots of mandibular molars.