Antimicrobial effect and pH of chlorhexidine gel and calcium hydroxide alone and associated with other materials

The purposes of this study were to evaluate the effectiveness of 2% chlorhexidine (CHX) gluconate gel, calcium hydroxide [Ca(OH)2] and their combination with iodoform and zinc oxide powder as intracanal medications against select microorganisms, and to measure the pH changes caused by these medications. Antimicrobial activity was determined by the agar diffusion method. The zones of growth inhibition were measured and the results were analyzed statistically by Kruskal-Wallis test (p<0.05). The pH of the pastes was measured right after preparation, after 24 h and 1 week later. The largest mean zones of microbial inhibition were produced by 2% CHX gel, followed by Ca(OH)2 + 2% CHX gel + iodoform, Ca(OH)2 + 2% CHX gel, Ca(OH)2 + 2% CHX gel + zinc oxide, and Ca(OH)2 + water. The mean pH of all medications stayed above 12.0 during the whole experiment, except for CHX gel (pH=7.0). The results of this study showed that all medications had antimicrobial activity, but the most effective against the tested microorganisms were 2% CHX gel, followed by its combination with Ca(OH)2 and iodoform.     

人健康和炎性牙槽骨成骨细胞COX-2、PGE2、OPG,RANKL的表达

目的：初步探讨COX-2、PGE2、OPG和RANKL在牙周炎发病机制中所起的作用及其相互关系。方法：采用组织块法对人健康和牙周炎性牙槽骨进行体外培养和传代,加入含100μg/LrhOPG的不含胎牛血清的DMEM2mL。严格按照ELISA试剂盒说明进行操作,获得各指标的检测数值。结果：牙周炎组RANKL、PGE2、COX-2的表达较健康组明显增高,OPG的表达较健康组明显降低。加入rhOPG后,牙周炎组RANKL、PGE2、COX-2的表达明显降低;OPG表达明显增加。健康组RANKL、PGE2、COX-2表达明显降低;OPG表达增加。结论：RANKL、PGE2、COX-2可促进牙周炎的发生、发展,而OPG对牙周炎的发生、发展可起抑制作用,同时表明人工重组OPG可能协同其内源性OPG来共同抑制RANKL、PGE2、COX-2的活性。     

口腔颌面部骨化性纤维瘤MMP-2、BMP-2的表达及意义

目的：检测MMP-2、BMP-2基因在口腔颌面部骨化性纤维瘤（Oral and Maxillofacial ossifying fibroma，OMOF）中的表达情况，分析其与肿瘤病理分型、临床分级之间的关系，并探讨其作为0MOF基因治疗靶基因的可能性。方法：采用免疫组织化学En Vision法检测27例OMOF标本及8例颌骨非肿瘤组织中MMP-2、BMP-2基因的表达，SPSS统计软件分析所得数据。结果：27例0MOF标本中9例BMP-2阳性表达（33．3％），18例MMP-2阳性表达（66．7％），均定位于细胞浆与细胞核；而8例非肿瘤骨组织无-例表达；MMP-2蛋白的表达与肿瘤大小、临床分型、患者年龄与性别均无关，BMP-2蛋白的表达与肿瘤大小及年龄、临床病理分型有关（P〈0．05），但与患者性别无关。结论：MMP-2蛋白比BMP-2蛋白在OMOF组织中的表达更高，因此将其作为研究0MOF免疫治疗靶点具有一定可行性。     

丙酮酸激酶M2与CD276在头颈鳞癌中的表达及临床意义

目的: 观察丙酮酸激酶M2（pyruvate kinase M2,PKM2）和B7H3（CD276）在头颈鳞癌（head and neck squamous cell carcinoma,HNSCC）和正常口腔黏膜中的表达,探讨PKM2与CD276的相关性。方法: 应用免疫组织化学方法检测PKM2和CD276在70例HNSCC及18例正常口腔黏膜组织中的表达水平,分析PKM2和CD276的表达水平与HNSCC临床病理特征的关系。采用SPSS 13.0软件包对数据进行统计学分析。结果: PKM2和CD276在HNSCC 的表达水平比正常黏膜组织高。PKM2和CD276的表达水平与TNM分期相关（P<0.05）,与患者性别、年龄、病理分级无相关性（P>0.05）。CD276在头颈鳞癌中的表达与PKM2的表达呈正相关。结论: PKM2和CD276在HNSCC的高表达与肿瘤恶性进展相关。PKM2可能通过增加CD276的表达而参与免疫调控。     

Colour and translucency of opaque-shades and body-shades of resin composites

The purpose of this study was to evaluate the optical properties--not only the translucency but also the colours--of opaque-shade resin composites. The CIELAB parameters (L*, a* and b*) of disks of A2 and opaque A2 (OA2) shades of Charisma (Heraeus-Kulzer), Solare (GC) and Filtek Supreme (3M) were evaluated on backings of black, white and the material itself to calculate the translucency parameter (TP) and the colour differences (delta E*) between A2 and OA2. A two-way analysis of variance (anova) for the TP indicated a less statistically significant TP value in the OA2 shade than the A2 shade for all products. As for the products, Charisma showed a statistically greater TP value than the other two products. Regarding the delta E* between A2 and OA2, all the products revealed clinically perceptible colour differences (delta E* > 3.3). Hence, we must take the colour differences of opaque-shade resin composites into consideration, as well as the translucency of the materials, for a clinically acceptable colour match of the restoration.     

Intranuclear cell uptake and toxicity of titanium dioxide and zirconia particles as well as bacterial adhesion on dental titanium- and zirconia-implants

ObjectivePrevious studies have shown that particles can be released from dental titanium (Ti)- and zirconia (ZrO₂)-implants. Titanium dioxide (TiO₂)- and ZrO₂-particles were compared regarding their toxicity and intranuclear cell uptake as well as the adhesion of various anaerobic bacteria on Ti- and ZrO₂-implants.MethodsCyto- and genotoxicity of TiO₂-microparticles (TiO₂-MPs) and TiO₂-nanoparticles (TiO₂-NPs) in periodontal ligament (PDL)-hTERT cells were determined with XTT test and DNA damage with comet assay. Particle sizes of TiO₂- and ZrO₂-particles were measured with scanning electron microscope. Intranuclear uptake in PDL-hTERT cells was determined with laser scanning confocal microscopy. Adhesions of relevant anaerobic mouth bacteria Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans on Ti- and ZrO₂-implants were investigated by cultivation and counting bacterial colonies.ResultsParticle size measurements revealed that 99% of the TiO₂-NPs had a size below 100 nm and 88% of the TiO₂-MPs sizes were between 50 and 200 nm. Following EC₅₀ values were found for particles (mg/l): 92 (TiO₂-MPs) and 15 (TiO₂-NPs). A significant increase in olive tail moment (OTM) was found for TiO₂-NPs at a concentration of 1/10 EC₅₀. TiO₂- and ZrO₂-NPs had a higher intranuclear cell uptake efficiency, compared to corresponding TiO₂- and ZrO₂-MPs. All investigated particles could be detected in cell nucleus. Adhesion of all investigated bacterial species was significantly higher on Ti-implants, compared to ZrO₂-implants.ConclusionTi usually develops an oxide layer (TiO₂). Particles released from Ti-implants should be TiO₂-particles or Ti-particles coated with a TiO₂-layer. Toxicity of released Ti-particles depends on their oxidation state and on their size (NP or MP). Particularly, NPs were more cyto- and genotoxic compared to the corresponding MPs. TiO₂- and ZrO₂-NPs showed a significant increase in the intranuclear cell uptake ratio at higher exposure concentration, compared to lower concentrations and consequently might lead to a higher potential of DNA damage. Adhesion of bacteria to ZrO₂-implants is reduced, compared to Ti-implants. Therefore, ZrO₂-implants might contribute to reduced biological complications (e.g. periimplantitis).     

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目的 探讨基质金属蛋白酶-2(MMP-2)和基质金属蛋白酶抑制剂-2(TIMP-2)在复发性阿弗他溃疡(RAU)中的表达及意义.方法 选取2007年1月至2010年1月中国医科大学口腔医学院综合急诊科收治的36例RAU患者,按照临床诊断分为3组,其中A组(轻型溃疡)19例、B组(疱疹样溃疡)11例、C组(重型溃疡)6例.再选择5例口腔黏膜正常者作为对照.采用免疫组化和RT-PCR方法分别检测各组对象口腔黏膜组织中MMP-2和TIMP-2的表达.结果 MMP-2、TIMP-2在各组对象口腔黏膜组织中均有表达,其表达的强度不同.MMP-2、TIMP-2在溃疡中的表达比正常黏膜显著增高(P＜0.05).MMP-2在重型溃疡中的表达明显高于轻型和疱疹样溃疡(P＜0.05);轻型和疱疹样溃疡中的表达差异无统计学意义(P＞0.05);TIMP-2在轻型、疱疹样、重型溃疡中的表达差异无统计学意义(P＞0.05).结论 MMP-2和TIMP-2在RAU中均表达增强,其二者的失衡可能参与发病过程且与病损的深度有关.     

人类牙周膜组织中MMP-2及TIMP-2的比较研究

目的：比较基质金属蛋白酶-2（MMP-2）和基质金属蛋白酶抑制因子-2（TIMP-2）在健康牙周组织（PDL）和病变牙周组织中的表达。方法：收集20例健康PDL和病变PDL组织样本,用ELISA法检测其中的MMP--2,TIMP-2水平。结果：牙周炎患者组PDL中的MMP-2的水平明显高于健康组（P〈0．01）,牙周炎患者组PDL中的TIMP-2的水平高于健康组（P〈0．05）,但MMP-2／TIMP-2明显增高。结论：研究提示MMP-2／TIMP-2失调与牙周组织破坏有关。     

The combined effect of nitrous oxide and oxygen and electrical stimulation during restorative dental treatment

A total of 124 adult patients were treated with nitrous oxide (N2O) and oxygen (O2), an electrical analgesic, or a combination of N2O/O2 and an electrical analgesic during restorative dental procedures. The use of electrical analgesic or N2O/O2 without local anesthetics resulted in a high failure rate and poor patient acceptance. However, combining N2O/O2 sedation with electrically induced analgesia resulted in a statistically significant improvement over either technique used alone, and provided an overall 81% success rate when used during restorative dentistry.     

cbfa1、satb2双基因共表达载体的构建及鉴定

目的:构建携带cbfa1和satb2双基因的慢病毒真核表达载体。方法:采用PCR技术,从质粒中扩增基因cbfa1和satb2,经TA克隆、酶切筛选后,对阳性重组子进行商业测序鉴定。将测序正确的cbfa1和satb2分别插入pIRES上、下游的相应酶切位点中,构建pIRES-cbfa1-satb2。然后通过双酶切,得到cbfa1-Ires-satb2片段,将其插到含有neo/kana基因的慢病毒载体pLentinTrident1-CMV的相应酶切位点上,构建慢病毒真核表达载体pLentinTrident1-CMV-cbfa1-Ires-satb2。结果:通过PCR技术成功扩增了cbfa1和satb2基因,借助中间载体pIRES中的内部核糖体进入位点,将cbfa1和satb2同时连到了慢病毒载体pLentinTrident1-CMV上,经PCR、酶切及测序验证,质粒构建成功。结论:本实验成功构建了携带cbfa1和satb2双基因的慢病毒真核表达载体,为进一步研究2种基因的功能奠定了基础。     

CCL2和CCR2在唾液腺腺样囊性癌中的表达及意义

目的 研究CCL2和CCR2在唾液腺腺样囊性癌（salivary adenoid cystic carcinoma, SACC）中的表达及其与临床病理特点之间的关系。方法 采用免疫组织化学染色方法检测CCL2、CCR2在60例SACC及12例正常唾液腺组织中的表达情况,并分析其与临床病理特征之间的关系。采用 SPSS 19.0软件包对实验结果进行统计学分析。结果 与正常唾液腺组织相比,CCL2和CCR2在 SACC组织中均呈现高表达,阳性表达率分别为91.7%和88.3%。CCL2和CCR2的表达与肿瘤临床分期、神经侵袭、肿瘤转移显著相关（P<0.05）;与性别、年龄、病理分型无显著相关性（P>0.05）。结论 CCL2、CCR2的表达与SACC的临床病理特征密切相关,检测两者的表达对SACC的诊断和临床病理研究具有重要的参考价值。     

Bcl-2、MDM2和p21在口腔白斑和口腔鳞状细胞癌中的表达水平研究

目的：了解Bcl-2、MDM2、p21在人口腔正常黏膜、白斑、鳞状癌细胞中的表达情况.方法：采用免疫组化二步法检测15例人正常口腔黏膜、15例单纯增生性白斑、10例异常增生性白斑,25例口腔鳞癌中Bcl-2、MDM2和p21蛋白的表达情况.结果：Bcl-2、MDM2蛋白在异常增生性白斑和口腔鳞癌中的表达明显高于正常口腔黏膜上皮细胞;p21蛋白在异常增生性白斑和口腔鳞癌中的表达明显低于正常口腔黏膜上皮细胞.结论：Bcl-2、MDM2和p21三者与口腔黏膜癌变具有相关性.     

RECK基因和基质金属蛋白酶-2在成釉细胞瘤的表达及相关性研究

目的探讨RECK和基质金属蛋白酶-2（MMP-2）的表达与成釉细胞瘤（AB）临床生物学行为的关系及相关性。方法应用免疫组化EliVision^TM plus法检测69例AB（原发45例,复发24例）、6例成釉细胞癌和16例牙源性角化囊性瘤（KCOT）中RECK、MMP-2蛋白的表达,同时采用RT-PCR方法检测22例AB（原发12例,复发10例）、2例成釉细胞癌和16例KCOT中RECK、MMP-2mRNA的表达水平。所有数据采用SPSS13．0统计软件包进行统计学分析。结果RECK蛋白的阳性表达率在KCOT、AB和成釉细胞癌中依次明显降低（P〈0．05）,且复发AB显著低于原发AB（P〈0．01）;AB和成釉细胞癌的MMP-2蛋白阳性表达率均显著高于KCOT（P〈0．05）：RECK蛋白与MMP-2蛋白在AB中的表达呈负相关（r=-0．431,P〈0．001）。RECKmRNA在AB、KCOT中均见表达,但在AB的表达较KCOT显著降低（P〈0．001）．成釉细胞癌中则无表达：MMP-2mRNA在KCOT、AB和成釉细胞癌中均见表达,但在AB的表达水平较KCOT显著增高（P〈0．001）,在成釉细胞癌中均呈高水平表达：复发AB的RECKmRNA表达水平较原发AB显著降低（P〈0．05）,但复发与原发AB的MMP-2mRNA表达之间差异无统计学意义：RECKmRNA与MMP-2mRNA在AB中的表达水平无相关性（P〉0．05）。结论RECK表达降低或缺失及MMP-2表达增高与AB的临床生物学行为密切相关。RECK可能通过转录后水平调控MMP-2参与AB的侵润、复发和恶性转化过程。     

P53 and MDM2 co-expression in tobacco and betel chewing-associated oral squamous cell carcinomas

Oral cancers of tobacco and betel chewers represents a unique in-vivo model to understand the genotoxic effect of tobacco and betel carcinogens on oncogenes and tumor suppressor genes. Coordinated interactions of p53 and MDM2 play an important role in regulation of critical growth control gene following exposure to DNA damaging agents. The purpose of this study is to determine if the tumor suppressor function of p53 is inactivated by mutation or other alternative mechanisms in carcinogen-induced oral squamous cell carcinoma (SCC), and to investigate the clinicopathological significance of p53 and MDM2 expression. The p53 mutation in oral SCC of tobacco and betel chewers (n=40) was detected by polymerase chain reaction - single strand conformation polymorphism (PCR-SSCP) analysis and immunohistochemistry (IHC) was done to investigate p53 and MDM2 proteins overexpression. The incidence of p53 mutation was relatively low (17.5%), but there was a high prevalence of MDM2 overexpression (72.5%). In the total of 40 cases, IHC phenotype showed p53 positive immunostaining with MDM2 positive immunostaining (p53+/MDM2+) 62.5%, p53 negative immunostaining with MDM2 negative immunostaining (p53-/MDM2-) 15%, p53 positive immunostaining with MDM2 negative immunostaining (p53+/MDM2-) 12.5%, and p53 negative immunostaining with MDM2 positive immunostaining (p53-/MDM2+) 10%. A significant correlation was found between MDM2 and p53 overexpression (p=0.0289). Moreover, p53+/MDM2+ phenotype was significantly associated with poorly differentiated tumors (p= 0.0007). These results conclude that other factors than p53 mutation is likely to be the targets of tobacco/betel carcinogens and MDM2 may play an important role in tobacco/betel chewing-related oral SCCs. Overexpression of MDM2 protein may constitute an alternative mechanism for p53 inactivation.     

肿瘤相关巨噬细胞和MMP-2在成釉细胞瘤中的表达及意义

目的：探讨肿瘤相关巨噬细胞（ TAMs）和基质金属蛋白酶?2（ MMP?2）在人成釉细胞瘤（ ABs）中的表达及意义。方法：采用免疫组化通用二步法,分别检测43例ABs和10例正常口腔黏膜中CD68标记的巨噬细胞数目及MMP?2的表达情况。结果：TAMs和MMP?2在ABs中的表达均高于正常黏膜,差异有统计学意义（ P＜0．01）。在ABs中,TAMs主要表达于肿瘤间质,MMP?2主要表达于肿瘤实质,MMP?2表达强度随着TAMs计数增加而增加,二者呈正相关关系（ r＝0．331,P＜0．05）。结论：ABs中TAMs和MMP?2的共同表达可能在其发生发展中发挥重要作用。     

口腔鳞状细胞癌上皮型钙依赖黏附蛋白及基质金属蛋白酶-2表达的意义

目的　了解上皮型钙依赖黏附蛋白 (E cd)、基质金属蛋白酶 - 2 (MMP 2 )在口腔鳞癌 (OSCC)中的表达及相互关系。方法　在 77例OSCC组织中 ,应用免疫组化技术标记E cd和MMP 2。结果　 77例OSCC中E cd蛋白表达与OSCC的WHO组织学分级、临床分期、浸润深度和淋巴结转移情况密切相关 (P <0 .0 5 ) ;MMP 2蛋白表达与OSCC的浸润深度、临床分期和淋巴结转移情况相关 (P <0 .0 5 ) ;E cd蛋白表达与MMP 2表达呈负相关 ;多因素分析表明 ,E cd和MMP 2是影响OSCC淋巴结转移的重要因素。结论　测定OSCC组织中E cd和MMP 2蛋白表达 ,对阐述OSCC浸润与转移机制有一定的理论意义 ,且对临床判断患者预后及指导治疗有帮助     

口腔白斑和癌组织中Smad4、Bel-2的表达及其相关性研究

目的：检测口腔白斑和癌组织中Smad4和Bcl-2的表达情况，探讨二者在口腔白斑的癌变过程中的变化及其相互关系。方法：免疫组织化学SABC法检测Smad4蛋白表达情况及Polymer法检测Bcl-2蛋白的表达情况。结果：Smad4蛋白在正常组织、白斑及癌组织中阳性表达率分别是100.0％、92.3％和33.3％，阳性表达差异有统计学意义（P〈0.01）；Bcl-2蛋白在正常组织中、白斑及癌组织中阳性表达率分别是30.0％、53.8％和100.0％，阳性表达差异有统计学意义（P〈0.01）；Smad4蛋白表达与Bcl-2蛋白表达呈负相关（r=-0.854，P〈0.01）。结论：Smad4和Bcl-2可能参与了口腔癌变的过程：在鳞癌的发生发展过程中，Smadd缺失表达和Bcl-2的过表达两者可能单独或协同参与。     

Microbiological and clinical effects of chlorhexidine digluconate and hydrogen peroxide mouthrinses on developing plaque and gingivitis

While the ability of chlorhexidine (CHX) to prevent plaque formation and inhibit the development of gingivitis has been well documented in the literature, the therapeutic value of hydrogen peroxide (H2O2) in preventing gingivitis is in dispute. The purpose of this study was to compare the clinical and microbiological effects of an established therapeutic agent, such as chlorhexidine with that of H2O2 in the experimental gingivitis model. Following a period of stringent oral hygiene, 32 subjects were allocated to 1 of 3 treatment groups which were balanced on the basis of their pre-experimental gingivitis scores. The subjects then refrained from any oral hygiene for 21 days. During this period, they rinsed twice a day with either a placebo, 0.12% CHX, or a 1% H2O2 mouthrinse. After 21 days, supragingival and marginal plaque was collected from each subject and assayed for total cultivable microbiota, total facultative anaerobes, facultative Streptococci, Actinomyces, Fusobacterium, Veillonella and Capnocytophaga. At the end of the experimental period, the group rinsing with 0.12% CHX showed 95% reduction in gingivitis incidence, 100% reduction in bleeding sites, and 80% reduction in plaque scores compared to the group rinsing with placebo. Conversely, the group using 1% H2O2 showed a marginal reduction in gingivitis incidence of 15% and a 28% reduction in bleeding sites compared to the placebo group, but no significant reduction in plaque scores. The microbiological results showed that 0.12% CHX was an excellent broad-spectrum antimicrobial agent which significantly reduced the number of both facultative and obligate anaerobes in plaque.(ABSTRACT TRUNCATED AT 250 WORDS)