纳米增韧陶瓷的初步生物安全性评价

目的初步评价牙科全瓷材料纳米增韧(NF)氧化铝陶瓷的生物安全性。方法根据ISO 7405/GB 16886标准,分别通过体外细胞毒性(琼脂覆盖法)、急性溶血、口腔黏膜刺激以及经口急性全身毒性实验,初步评价材料的生物安全性。结果NF陶瓷材料无细胞毒性;溶血率仅0.275%,远低于5%的安全标准;与实验材料接触的颊黏膜未见异常反应,组织切片观察评分为0,无病理性改变;急性全身毒性实验中动物无中毒反应,肝肾等重要组织切片未见病理改变。结论新型纳米增韧氧化铝陶瓷具有较好的生物安全性。     

几种根管冲洗液对L929细胞毒性的实验研究

目的:采用MTT法比较臭氧水溶液与临床常用根管冲洗液对L929细胞的细胞毒性。方法:应用碘量法测定一种臭氧发生器产生臭氧水溶液的最高浓度。体外培养L929细胞,分别以2.15mg/L臭氧水溶液(实验测得最高浓度臭氧水溶液)、3%过氧化氢液、1%次氯酸钠和17%EDTA液作用于细胞6h、12h和24h,生理盐水作为空白对照组,采用MTT法检测不同时间不同组细胞增殖度,测定各组细胞活性。结果:试验用臭氧发生器所产生最高浓度臭氧水溶液浓度约2.15mg/L;MTT实验结果显示,2.15mg/L臭氧水溶液对L929细胞无明显细胞毒性,与阴性对照生理盐水组相比不具有统计学差异。而3%过氧化氢、1%次氯酸钠和17%EDTA液均具有显著的细胞毒性,且随时间延长表现出更强的细胞毒性。细胞毒性按1%次氯酸钠、3%过氧化氢、17%EDTA顺序递减。结论:2.15mg/L臭氧水溶液具有优良的生物相容性,细胞毒性显著低于临床常用的其他根管冲洗剂。     

复方洗必泰含漱液和复方硼酸含漱液治疗口腔炎症性疾病的近期疗效观察

复方洗必泰含漱液和复方硼酸含漱液治疗口腔炎症性疾病的近期疗效观察常州市钟楼口腔医院陈兰萍，唐玲燕常州市第一人民医院胡祥珍口腔含漱液品种较多，常用的有复方硼酸含漱液（即朵贝尔氏液）和复方洗必泰含漱液（即口泰），２年多临床应用复方洗必泰含漱液的疗效明显优...     

六种纳米载银无机抗菌剂的体外细胞毒性比较

目的通过分析6种纳米载银无机抗菌剂不同浓度稀释液的体外细胞毒性，初步评价纳米载银无机抗菌剂的生物安全性。方法将载银磷酸锆（FUMAT T200-4）、载银磷酸复盐（HN300）、载银氢氧化钠锆（Novaron）、载银磷酸锆（康旺）、载银二氧化硅（MOD）、载银磷酸锆（SR1000）配置成100、50、25、12．5g/L 4种不同质量浓度的稀释液，采用噻唑蓝（MTT）比色法检测各浓度稀释液对小鼠成纤维细胞L-929的体外细胞毒性并进行比较。结果6种纳米载银无机抗菌剂的高浓度稀释液对小鼠成纤维细胞L-929均有毒性，随着浓度下降，细胞毒性亦下降，当浓度≤25g／L时已无毒性。对6种纳米载银无机抗菌剂的体外细胞毒性进行比较，结果显示其安全性为FUMAT T200-4、康旺、SR1000〉HN300〉Novaron、MOD。结论纳米载银无机抗菌剂FUMAT T200-4、康旺及SR1000的生物安全性较好，具有作为口腔材料应用的可行性。在应用时，其浓度应≤25g／L，以确保对人体的安全性。     

多壁纳米碳管增强义齿基托树脂的生物安全性研究

目的探讨多壁纳米碳管增强义齿基托树脂（MWCNTs／PMMA）复合材料的生物学性能。方法进行MWCNTs／PMMA复合材料制备，参照ISO7406技术报告相关标准，对MWCNTs／PMMA复合材料生物安全性进行体内及体外试验．包括细胞毒性试验、急性全身毒性试验及口腔黏膜刺激试验．评价复合材料的生物学性能。结果细胞毒性试验评价级别为1级．无明显细胞毒性作用：急性全身毒性试验未见任何急性毒性反应：口腔黏膜刺激试验未见异常组织学反应。结论MWCNTs／PMMA复合材料具有良好的生物安全性．安全无毒。     

洗必泰消毒印模材料抑菌效果的观察

口腔临床制取的印模表面常携带有大量细菌、病毒及真菌等病原微生物,这些微生物不消除可能会导致医务人员、病员和技工之间的交叉感染。而常规消毒方法,如浸泡、喷涂等,会对印模的精度带来影响,同时用于浸泡和喷涂的消毒剂往往对人体有较强的毒性,对金属托盘也有一定的腐蚀性闭。在印模材料组分中加入消毒剂以制成消毒型印模材料则可有效解决上述问题。本研究使用不同质量浓度洗必泰调拌藻酸盐印模材料以制成洗必泰消毒型印模,并研究其消毒效果,以探求一种快捷、有效、方便的印模消毒方法。     

牙科高速手机辅助微创拔牙的冷却水选择初探

目的通过对临床常用的消毒牙科综合治疗台水路系统方法:次氯酸钠法消毒效果的评价,初步探讨牙科高速手机辅助微创拔牙的冷却水选择。方法随机选择10台独立水源口腔综合治疗台,分别采集其水路经700 mg/L次氯酸钠消毒后接诊患者前(8∶00)、中午下班前(11∶30)和下午下班前(17∶30)3个时间点高速手机出水口水样,检测并计算总菌落数。所得数据利用SPSS 19.0统计软件进行广义估计方程进行分析。结果不同时间点水样微生物总菌落数不同。未接诊病人时,水样中未检测出细菌。下午时间点细菌数量最多,中午时间点细菌数量次之。广义估计方程分析结果显示不同测量时间点上的微生物菌落数的差异具有统计学意义(P<0.05)。结论次氯酸钠消毒剂对口腔综合治疗台水路具有良好消毒效果,但随着时间的推移在综合治疗台使用过程中,水路系统会遭到污染,达不到拔牙手术无菌要求,需要选择其他方式的手机冷却水系统。     

二步烧结牙科氧化锆陶瓷细胞毒性评价

目的:对二步烧结牙科可切削牙科纳米氧化锆陶瓷细胞毒性进行初步评价.方法:选择了2种体外试验即四氮唑盐比色法(MTT)体外细胞毒性试验和急性溶血试验.结果:二次烧结的氧化锆陶瓷的体外细胞毒性均为0级;溶血率分别为0.915%和1.177%.均小于5%,无明显的溶血反应.结论:初步证实了二次烧结的氧化锆陶瓷具有人体应用的生物安全性基础,无细胞毒性,无溶血反应.     

口腔材料与器械

国产碳纤维桩的固位力实验；MTT法评价国产碳纤维桩材料的细胞毒性；五种牙本质粘接剂体外细胞毒性研究；环氧乙烷对牙科手机灭菌效果及机械性能影响的实验研究；不同材料根管桩剪切粘结强度的比较；树脂透明牙模型用于根管治疗操作训练的效果评价；反向沉淀法制备牙科纳米氧化锆粉体；口腔修复常用合金稳态电位的测定；三种金属处理剂对金属与复合树脂间剪切粘接强度影响的研究。[编者按]     

乳化洗必泰洗手剂的初步研究

乳化洗必泰洗手剂是由不同浓度的醋酸洗必泰消毒剂加入表面活性剂，保湿剂，富脂剂等，经过ＰＨ调整后在常温下混合而成。通过实验室抑菌试验的对比，结果与相对应浓度洗必泰水剂无明显差异。为临床医护人员提供了一种既具有去污消毒效果，又起到皮肤保健作用的新型洗手剂。     

In vitro susceptibility of Candida albicans to four disinfectants and their combinations

AIM: The aim of this study was to evaluate the susceptibility of seven strains of Candida albicans to four disinfectants: iodine potassium iodide, chlorhexidine acetate, sodium hypochlorite and calcium hydroxide. In addition, all possible pairs of the disinfectants were tested in order to compare the effect of the combination and its components. METHODOLOGY: Filter paper discs were immersed in standardized yeast suspensions and then transferred to disinfectant solutions of different concentrations and incubated at 37 degrees C for 30 s, 5 min, 1 h and 24 h. After incubation the filter paper discs were transferred to vials with PBS and glass beads that were then vigorously shaken for dispersal of the yeast cells. PBS with resuspended yeasts was serially diluted 10-fold. Droplets of 25 microL from each dilution were inoculated on TSB agar plates and incubated in air at 37 degrees C for 24 h. The number of colony-forming units was then calculated from appropriate dilutions. RESULTS: C. albicans cells were highly resistant to calcium hydroxide. Sodium hypochlorite (5% and 0.5%) and iodine (2%) potassium iodide (4%) killed all yeast cells within 30 s, whilst chlorhexidine acetate (0.5%) showed complete killing after 5 min. Combinations of disinfectants were equally or less effective than the more effective component. All C. albicans strains tested showed similar susceptibility to the medicaments tested. CONCLUSIONS: This study indicates that sodium hypochlorite, iodine potassium iodide and chlorhexidine acetate are more effective than calcium hydroxide against C. albicans in vitro. However, combining calcium hydroxide with sodium hypochlorite or chlorhexidine may provide a wide-spectrum antimicrobial preparation with a long-lasting effect.     

Effect of six different peri‐implantitis disinfection methods on in vivo human oral biofilm

Objective: The aim of this human in vivo pilot study was to evaluate the efficacy of six antimicrobial agents on the surface decontamination of an oral biofilm attached to titanium implants. Design: For in vivo biofilm formation, we fixed titanium specimens to individual removable acrylic upper jaw splints (14 specimens in every splint), which were worn by four volunteers overnight for 12 h. The specimens were then treated with different antimicrobial agents for 1 min (Sodium hypochlorite, Hydrogen peroxide 3%, Chlorhexidingluconate 0.2%, Plax, Listerine, citric acid 40%). Afterwards, we quantified the total bacterial load and the viability of adhering bacteria by live or dead cell labelling in combination with fluorescence microscopy. Results: The total bacterial load on the titanium surfaces was significantly higher after incubation in the control solution phosphate‐buffered saline (PBS) than after disinfection in sodium hypochlorite, hydrogen peroxide, chlorhexidine, Plax, Listerine, and citric acid. Furthermore, a significantly lower ratio between dead and total adhering bacteria (bactericidal effect) was found after incubation in control PBS, Plax mouth rinse, and citric acid than after incubation in sodium hypochlorite, hydrogen peroxide, chlorhexidine, and Listerine. Conclusions: All tested antiseptics seem to be able to reduce the total amount of microorganisms accumulating on titanium surfaces. Furthermore, sodium hypochlorite, hydrogen peroxide, chlorhexidine, and Listerine showed a significant bactericidal effect against adhering bacteria. To cite this article:
Gosau M, Hahnel S, Schwarz F, Gerlach T, Reichert TE, Bürgers R. Effect of six different peri‐implantitis disinfection methods on in vivo human oral biofilm.
Clin. Oral Impl. Res. 21 , 2010; 866–872.
doi: 10.1111/j.1600‐0501.2009.01908.x     

Comparison of antimicrobial substantivity of root canal irrigants in instrumented root canals up to 72 h: an in vitro study

Disinfection of the root canal system is one of the primary aims of root canal treatment. This can be achieved through the use of various antimicrobial agents in the form of irrigants and medicaments. The antimicrobial substantivity of 2% chlorhexidine gluconate, 1% povidone iodine, 2.5% hydrogen peroxide followed by 2% sodium hypochlorite, and 2% sodium hypochlorite alone as irrigants was assessed in instrumented root canals. 2% chlorhexidine showed antimicrobial substantivity lasting up to 72 h, followed by 1% povidone iodine, and 2% sodium hypochlorite. Thus 2% chlorhexidine should be used as a final rinse irrigant in endodontic treatment protocols.     

Effect of ozone on oral cells compared with established antimicrobials

Ozone has been proposed as an alternative antiseptic agent in dentistry based on reports of its antimicrobial effects in both gaseous and aqueous forms. This study investigated whether gaseous ozone (4 x 10(6) microg m(-3)) and aqueous ozone (1.25-20 microg ml(-1)) exert any cytotoxic effects on human oral epithelial (BHY) cells and gingival fibroblast (HGF-1) cells compared with established antiseptics [chlorhexidine digluconate (CHX) 2%, 0.2%; sodium hypochlorite (NaOCl) 5.25%, 2.25%; hydrogen peroxide (H(2)O(2)) 3%], over a time of 1 min, and compared with the antibiotic, metronidazole, over 24 h. Cell counts, metabolic activity, Sp-1 binding, actin levels, and apoptosis were evaluated. Ozone gas was found to have toxic effects on both cell types. Essentially no cytotoxic signs were observed for aqueous ozone. CHX (2%, 0.2%) was highly toxic to BHY cells, and slightly (2%) and non-toxic (0.2%) to HGF-1 cells. NaOCl and H(2)O(2) resulted in markedly reduced cell viability (BHY, HGF-1), whereas metronidazole displayed mild toxicity only to BHY cells. Taken together, aqueous ozone revealed the highest level of biocompatibility of the tested antiseptics.     

Antimicrobial effect of irrigant combinations within dentinal tubules

The aim of this study was to investigate sodium hypochlorite (with and without EDTA), chlorhexidine, and hydrogen peroxide in varying concentrations when used in sequence or in combination as endodontic irrigants. Sterile saline served as the control. Six standardized bovine incisor root specimens, which had been infected with Enterococcus faecalis (CG 110), were exposed to each solution. Following exposure to the test agents dentine samples were taken from within the lumina using ISO 023 to 035 burs. The dentine powder samples were incubated and the quantity of bacteria present assessed using spectrophotometry. All irrigant regimens were more effective than saline in killing bacteria. Chlorhexidine and sodium hypochlorite were similarly effective. At specific concentrations a synergistic effect was noted when mixtures of chlorhexidine and hydrogen peroxide were under test.     

The effect of various topical peri-implantitis antiseptics on Staphylococcus epidermidis, Candida albicans, and Streptococcus sanguinis

ObjectiveAlthough peri-implantitis has presented an ever increasing problem in modern dentistry, satisfying therapeutic strategies or scientifically based treatment recommendations are still not available. The main object of the present study was to evaluate the antibacterial efficacy of six different topical antiseptics on three test microorganisms attached to titanium implant specimens.Material and methodsFor biofilm formation, plane titan specimens were incubated either in Candida albicans, Streptococcus sanguinis, or Staphylococcus epidermidis for 2 h. The specimens were then treated with different topical antiseptics for 60 s (sodium hypochlorite 1.0%, hydrogen peroxide 3.0%, chlorhexidine gluconate 0.2%, citric acid 40.0%, Plax, or Listerine) and with sterile saline as control. Remaining vital fungi were quantified by means of a bioluminometric assay and the bacterial load and the viability of adhering S. epidermidis and S. sanguinis by live or dead cell labelling in combination with fluorescence microscopy.ResultsSodium hypochlorite was effective against all three species, whereas hydrogen peroxide was solely effective against C. albicans. CHX and Listerine showed antimicrobial activity against S. sanguinis and C. albicans and citric acid and Plax against both tested bacteria.ConclusionsNone of the tested antimicrobial agents, except for sodium hypochlorite, showed a significant in vitro effect on all three test microbes. Considering the possible toxicity of sodium hypochlorite, none of the tested – and so far widely used – antiseptics showed any broad-spectrum antimicrobial effect and could therefore not be recommended for the topical disinfection and detoxification of infected implant surfaces.     

Effect of Incorporation of Disinfectant Solutions on Setting Time, Linear Dimensional Stability, and Detail Reproduction in Dental Stone Casts

Purpose: The aim of this paper was to analyze the influence of incorporation of disinfectants during the cast die stone-setting time. Setting time, linear dimensional stability, and reproduction details on casts were measured.
Materials and Methods: Die stone type IV specimens with disinfection solutions (sodium hypochlorite 1%, glutaraldehyde 2%, chlorhexidine 2%) were incorporated in two concentrations (50%, 100%). The detail reproduction, dimensional stability, and setting time were tested in accordance with ADA recommendations.
Results: Disinfecting solutions promoted an increase in setting time compared to control; sodium hypochlorite was responsible for the highest setting time. The addition of undiluted sodium hypochlorite 1.0% led to contraction during setting, but the groups with 50% diluted sodium hypochlorite 1.0% and undiluted chlorhexidine 2.0% resulted in intermediate values compared to the other groups, thus matching the control. The others did not demonstrate any effect on expansion. For detail reproduction, it was observed that the control group presented results similar to the others, except those where sodium hypochlorite was added.
Conclusions The addition of sodium hypochlorite in both dilutions significantly altered, negatively, all the evaluated properties. But the addition of glutaraldehyde and chlorhexidine did not promote any significant alterations in the evaluated properties.     

Effectiveness of intracanal irrigants and medications against the yeast Candida albicans

An in vitro study was conducted to determine the susceptibility of the yeast Candida albicans to various intracanal irrigants and medications. The minimum inhibitory concentration (MIC) of sodium hypochlorite, hydrogen peroxide, chlorhexidine digluconate, and aqueous calcium hydroxide that is required to kill a standardized inoculum of C. albicans was determined. Growth of the yeast was measured by optical density. Sodium hypochlorite, hydrogen peroxide, and chlorhexidine digluconate were effective anticandidal agents with MICs of <10 microgram/ml, 234 microgram/ml, and <0.63 microgram/ml, respectively. Aqueous calcium hydroxide had no activity. A standardized inoculum of C. albicans cells was also placed in direct contact with either calcium hydroxide paste or camphorated para-monochlorophenol (CPMC), and candidal growth was assessed by colony counts on Sabouraud's dextrose agar. Calcium hydroxide paste and CPMC, when maintained in direct contact with C. albicans, were effective antifungal agents.     

Scanning electron microscopic study of the cleaning ability of chlorhexidine as a root-canal irrigant

AIM: To evaluate in vitro the cleaning of root-canal walls after irrigation with different irrigants. METHODOLOGY: A total of 36 recently extracted human teeth were divided into four experimental groups according to the irrigating solution used: saline; 2% chlorhexidine; 2.5% sodium hypochlorite; and 2.5% sodium hypochlorite + EDTA. The cleaning of the apical, middle and coronal thirds of the root canals was evaluated by scanning electron microscope examination using a 4-point scoring system. RESULTS: The best cleaning was obtained using 2.5% sodium hypochlorite and EDTA, followed by 2.5% sodium hypochlorite only (P < 0.05), whose cleaning was similar to chlorhexidine only in the cervical third. Cleaning by saline and 2% chlorhexidine was worse than the other two groups and was similar in all thirds. Better cleaning was found in the cervical and middle thirds for all groups with the worst results in the apical third. CONCLUSIONS: The apical third of the root canals was not cleaned as well as the middle and coronal thirds. Cleaning by chlorhexidine and saline was inferior compared to the cleaning by sodium hypochlorite with and without EDTA.