五倍子对牙周可疑致病菌蛋白酶和糖苷酶活性的抑制作用

目的　体外观察五倍子水提取物对牙周可疑致病菌胞外酶 (蛋白水解酶和糖苷酶 )活性的影响。方法　应用荧光分光光度计检测荧光底物的降解来测定酶活力。结果　除中间普菌的L -arginine -arylamidase活性不受五倍子的影响外 ,浓度0 .0 5 %～ 0 .10 %的五倍子可以抑制所测其他细菌≥ 5 0 %胞外酶底物的降解。结论　五倍子水提取物可有效抑制牙周可疑致病菌蛋白水解酶和糖苷酶活性 ,其抑制作用可能会阻碍细菌生长 ,降低细菌毒力 ,减缓牙菌斑的形成     

The effects of tetracycline, minocycline, doxycycline and ofloxacin on Prevotella intermedia biofilm

Prevotella intermedia, a black-pigmented, anaerobic, gram-negative bacterium, is associated with various type of periodontitis. Antibiotic treatments via a systemic or local route have been reported as being useful for treating periodontal disease. The purpose of this study was to examine the effects of four antibiotics, tetracycline (TET), minocycline (MINO), doxycycline (DOXY) and ofloxacin (OFLX) on P. intermedia biofilms at minimum inhibitory concentrations (MIC) from one-fold to 100-fold. MICs were determined for planktonic cells. Biofilm formation was determined with the crystal violet stain method and the bioactivities in the biofilms were determined with the adenosine triphosphate (ATP) -bioluminescent assay using a 96-well culture plate. At one-fold MIC, DOXY inhibited biofilm formation by P. intermedia ATCC 25611. Other antibiotics at one-fold MIC had no effects on the biofilm formation of tested bacterial strains. In P. intermedia ATCC 25611 biofilms, all the antibiotics tested showed inhibitory activities at five- to 100-fold MICs. In the biofilms of P. intermedia strains, except ATCC 25611, treated with three tetracycline antibiotics, the bioactivities were significantly increased, indicating the difficulties involved in designing antibiotic therapy for periodontal disease.     

A combination of a chemically modified doxycycline and a bisphosphonate synergistically inhibits endotoxin-induced periodontal breakdown in rats

BACKGROUND: Chemically modified non-antimicrobial tetracyclines (CMTs) have been shown to inhibit pathologically elevated collagenase (and other matrix metalloproteinase, MMP) activity and bone resorption in vivo and in vitro. METHODS: In the current study, suboptimal doses of CMT-8 (a non-antimicrobial chemically modified doxycycline) and a bisphosphonate (clodronate, an anti-bone resorption compound) were administered daily, either as a single agent or as a combination therapy, to rats with experimental periodontitis induced by repeated injection of bacterial endotoxin (LPS) into the gingiva. At the end of the 1-week protocol, the gingival tissues were dissected, extracted, and the extracts analyzed for MMPs (collagenases and gelatinases) and for elastase, and the defleshed jaws were morphometrically analyzed for alveolar bone loss. RESULTS: LPS injection significantly (P<0.001) increased alveolar bone loss and increased collagenase (MMP-8), gelatinase (MMP-9), and elastase activities. Treatment of the LPS-injected rats with suboptimal CMT-8 alone or suboptimal clodronate alone produced slight reductions in the tissue-destructive proteinases and no significant reductions in alveolar bone loss. However, a combination of suboptimal CMT-8 and clodronate "normalized" the pathologically elevated levels of MMPs, elastase, and alveolar bone loss, indicating synergistic inhibition of tissue breakdown in this animal model of periodontitis. CONCLUSIONS: Combination of a CMT and a bisphosphonate may be a useful treatment to optimally suppress periodontal destruction and tooth loss and in other tissue-destructive inflammatory diseases such as arthritis.     

Effects of doxycycline, minocycline, and tetracycline on cell proliferation, differentiation, and protein expression in osteoprecursor cells

Tetracyclines, including tetracycline (TC), minocycline (MINO), and doxycycline (DOXY), were widely used as topical therapy in treating periodontitis, which is an infectious disease of the gingival crevice caused by periodontopathic bacteria. In addition, TC is used during bone grafting procedures because of its anticollagenase activity, antibacterial effect, and fibroblast-stimulatory properties.In this study, the effects of TC on osteoprecursor cells were evaluated. The cytotoxic effect was determined by testing cell viability. Differentiation and mineralization were evaluated using an alkaline phosphatase activity test and alizarin red S staining. In addition, protein expressions related to bone formation, such as bone morphogenetic protein 2 (BMP-2), estrogen receptor α (ER-α), and estrogen receptor β (ER-β), were evaluated by using Western blot analysis.The morphology of the cells seemed normal, and their viability was not significantly affected when they were treated with 10 μM MINO and 10 μM DOXY. Cells treated with 10 μM DOXY showed alkaline phosphatase activity that was comparable to the control. Results from the Western blot analysis showed that TC, MINO, and DOXY reduced the expression of BMP-2 and ER-β. Normalization of the protein expressions showed that 10 μM DOXY retained 87% in BMP-2 and 85% in ER-β.Higher levels of these agents led to a dose-dependent decrease of cellular differentiation and protein expression. There are several commercially available agents for TC, which has to be considered when applying the TC in local delivery applications.     

Influence of nicotine and cotinine on epithelial colonization by periodontopathogens

BACKGROUND: Since smoking is an established risk factor for the development of periodontitis, the present study investigated whether nicotine and cotinine can make epithelial cells more prone to colonization by periodontopathogens. METHODS: Primary epithelial cell mono-layers were inoculated with nicotine and cotinine prior to adhesion experiments with Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. The number of bacteria associated with cells inoculated or not with nicotine or cotinine were assessed by an indirect culture viability assay. The same experimental set-up was used for assessing HeLa cells exposed to cigarette smoke extract (CSE). RESULTS: Primary epithelial cells inoculated with concentrations of nicotine and cotinine, found in smokers and non smokers, did not show significant differences (P>0.05) in colonization susceptibility to A. actinomycetemcomitans. When these concentrations were increased to 1 mg/ml, a significant (P<0.05) and species-specific effect of the colonization susceptibility of epithelial cells was observed: It increased for A. actinomycetemcomitans, while it decreased for P. gingivalis. For both species the effects were more pronounced for nicotine, although this was not statistically significant. The change in colonization susceptibility did not result from alterations of the bacterial viability due to nicotine or cotinine. Treatment of HeLa cells with CSE also led to a species-specific variation in colonization tendency; i.e., increased for A. actinomycetemcomitans (P<0.05), but not for P. gingivalis. CONCLUSIONS: The susceptibility of epithelial cells to become colonized by either A. actinomycetemcomitans or P. gingivalis could be altered by nicotine, cotinine, or CSE in a time-dependent, species-specific manner. Whether these findings that support the hypothesis of an increased patient susceptibility for bacterial adhesion to epithelial cells in smokers are clinically relevant remains to be proven.     

Detection of two anaerobic periodontopathogens in children by means of the BANA and ELISA assays

The mouths of young children become colonized by a variety of bacteria, but there have been only a few studies that have sought the presence of periodontopathic species in this population. Almost all of these studies used culturing techniques rather than the newer detection methodologies for various periodontopathogens. Studies in adults have shown that Treponema denticola and Porphyromonas (Bacteroides) gingivalis can be detected in dental plaque by use of the BANA and ELISA diagnostic tests. In the present study, plaque samples from four subgingival sites in each of 157 children (aged from two to 18 years) were tested for BANA hydrolysis with a BANA reagent card, and for T. denticola and P. gingivalis with an ELISA assay. Anaerobic periodontopathogens hydrolyzing the BANA substrate were found to be present in at least one of four plaque samples in 88 children (56%). T. denticola and/or P. gingivalis were detected by ELISA in at least one plaque sample in each of 135 children (86%). This study shows that children are widely colonized by these micro-organisms. A higher proportion of Black children than Caucasian children was colonized by these BANA-positive organisms. Also, children having a parent with a documented history of periodontal disease were more likely to be BANA-positive than were children of parents with unknown periodontal status.     

Inhibition of peptidase and glycosidase activities of Porphyromonas gingivalis, Bacteroides intermedius and Treponema denticola by plant extracts

Aqueous extracts from 5 plants used widely in Kenya as chewing sticks (mswaki) for the control of oral hygiene were tested for their ability to inhibit extracellular peptidase and glycosidase enzyme activities produced by the periodontopathic bacteria Porphyromonas gingivalis (formerly Bacteroides gingivalis), Bacteroides intermedius and Treponema denticola. The plants studied were Rhus natalensis, Cupressus hisitanica, Sida cordifolia, Olea africana and Euclea divinorum. Protease activities, including glycylprolyl dipeptidase and trypsin-like activities of P. gingivalis, chymotrypsin-like and glycylprolyl dipeptidase activities of B. intermedius and the trypsin-like activity of T. denticola, were particularly affected by extracts from Rhus natalensis and Euclea divinorum. Glycosidase activities were generally less affected with the notable exceptions of the inhibition of beta-mannosidase activity of P. gingivalis by all extracts and the inhibition of neuraminidase activity of T. denticola by Rhus natalensis and Euclea divinorum. Generally, these same proteolytic and glycosidic activities were inhibited by tannic acid and to lesser extents by gallic acid and gallic acid methyl ester. An inhibitory component, present in all extracts, exhibited physical and chemical properties identical to those of tannic acid. The inhibition of these enzyme activities is likely to reduce the virulence of these periodontophathic bacteria and to reduce the rate of dental plaque formation.     

Effects of chlorhexidine on proteolytic and glycosidic enzyme activities of dental plaque bacteria

Chlorhexidine was tested for its ability to inhibit a wide range of glycosidic and proteolytic enzyme activities produced by Treponema denticola, Porphyromonas gingivalis, Bacteroides intermedius, Actinobacillus actinomycemcomitans, Capnocytophaga sputigena, Capnocytophaga gingivalis, Capnocytophaga orchracea, Capnocytophaga sp., Actinomyces viscosus, Streptococcus mitior, Streptococcus mutans, Streptococcus sobrinus, Streptococcus mitis, Streptococcus anginosus, Streptococcus oralis and Streptococcus sanguis. The enzymes produced by Capnocytophaga spp. were the most resistant to inhibition by chlorhexidine while the hydrolysis of proteolytic substrates by all the other species was markedly susceptible to inhibition with less than 0.125 mM chlorhexidine inhibiting enzyme activities by greater than or equal to 50%. Glycosidase activities, of all species, were generally more resistant to inhibition, especially neuraminidase activity. Chlorhexidine at less than 0.032 mM inhibited the degradation of bovine serum albumin by suspensions of dental plaque bacteria. These observations support an hypothesis that chlorhexidine exerts a bacteristatic effect in vivo, in part, by reducing the ability of dental plaque bacteria to degrade host-derived proteins and glycoproteins which normally provide essential nutrients for growth.     

Effect of modified Widman flap surgery and systemic tetracycline on the subgingival microbiota of periodontal lesions

33 subjects with evidence of active destructive periodontal disease were treated by modified Widman flap surgery and systemic tetracycline (1 g/day for 21 days). Subgingival plaque samples were taken from 41 sites in 12 of these subjects before and 6 months after therapy for predominant cultivable microbiota studies. Mean pocket depth and attachment levels in the 41 sampled sites were 7.1 +/- 2.9 mm and 7.7 +/- 3.2 mm prior to therapy and 4.8 +/- 2.3 mm and 6.2 +/- 3.4 mm after therapy. B. melaninogenicus and V. parvula were more frequently detected in samples taken after therapy, while S. intermedius, S. morbillorum, S. uberis and W. recta were less frequently detected after therapy. A. actinomycetemcomitans were detected in 7 sites pretherapy and 1 site post therapy. The frequency of detection of B. gingivalis and B. intermedius was virtually unchanged. The mean levels of the Actinomyces sp., A. actinomycetemcomitans, B. gingivalis, B. intermedius, S. morbillorum, S. uberis and W. recta were decreased after therapy, while the mean levels of B. melaninogenicus, S. mitis, S. sanguis II and V. parvula were increased after therapy. V. parvula showed the greatest increase to 8.2% of the microbiota. In the second phase of the study, subgingival plaque samples from 94 sites in the 33 treated subjects were analyzed by predominant cultivable techniques. As a result of therapy, 24 sites exhibited attachment loss greater than 2 mm, 23 sites exhibited "gain" greater than 2 mm and the remaining 47 sites were considered to be unchanging.(ABSTRACT TRUNCATED AT 250 WORDS)     

釉基质蛋白对化学处理钛表面磷灰石生成的影响

目的:研究釉基质蛋白对双重热酸蚀及碱热处理纯钛表面仿生矿化沉积磷灰石层的影响.方法:提取猪未萌恒牙胚表面EMPs,用SDS-PAGE电泳进行验证.纯钛片经抛光清洗,分别进行双重热酸蚀和碱热处理,放入含EMPs(150 μg/mL)的改良模拟体液(m-SBF)中浸泡7d,对照组为不含EMPs的m-SBF.扫描电镜观察试件表面形貌,X射线能谱,X射线衍射及傅里叶红外光谱等分析其元素成分及晶相结构.结果:酸蚀组经仿生矿化.对照组试件表面无沉积物生成,实验组加入EMPs,钛片表面有一定量的沉积物生成,能谱分析显示主要由Ca、P、O和C等元素组成.碱热处理组经仿生矿化,对照组与实验组试件表面均有沉积层形成,但后者有较多直径约为300～600nm的孔隙生成,元素组成主要为Ca、P、O和C,X射线衍射及傅里叶红外光谱分析显示沉积物为碳羟基磷灰石.结论:碱热处理纯钛表面有利于磷灰石层的形成,加入EMPs能促进磷灰石层的形成并改变其形貌.     

Inhibition of adsorption of oral streptococci to saliva treated hydroxyapatite by chitin derivatives.

This study estimated the effects of five chitin derivatives low molecular chitosan (LMCS), ethyleneglycol chitin (PEGT), carboxymethyl chitin (PCMT), sulphated chitosan (PSSS), and phosphorylated chitin (PPPT) on the adsorption of three oral streptococci to saliva-treated hydroxyapatite (S-HA). The adsorption was evaluated by measuring the optical density of the bacterial cell suspensions released from saliva-treated hydroxyapatite by 0.5 N HCl. The adsorption of test strains to S-HA progressively decreased in proportion to each additional volume of PEGT, PPPT, or PSSS. PPPT and PSSS quite effectively inhibited the adsorption of S. mutans onto S-HA, but were less effective against S. sanguis and S. mitis. PPPT, PSSS, and PCMT all markedly promoted the desorption of S. mutans cells pre-adsorbed onto S-HA. Pretreatment of S-HA with PPPT, PSSS, or PCMT significantly decreased the subsequent adsorption of S. mutans and S. mitis. Pretreatment of these cells with PEGT also decreased their adsorption to S-HA. These findings suggest that these chitin derivatives may change the ionic natures of the S-HA and the bacterial cell surface, resulting in a less favorable interaction.     

Effects of chemically modified starches in suspensions and lozenges on pH of human dental plaque

The aim was to evaluate chemically modified starches (CMS) from a cariologic point of view as alternatives to gum arabic in sugar-free lozenges. Two commercial CMS, Purity Gum 40 and Capsul, were selected due to their comparatively low availability to alpha-amylase in vitro. Both gelatinized CMS suspensions and lozenges were tested in vivo by measuring plaque pH. The results showed that suspensions of Purity Gum 40 or Capsul were less available to alpha-amylase in vitro than the soluble starch reference. However, the initial phase of amylolysis was comparatively rapid also with CMS. In spite of the slower rate of hydrolysis, suspensions of the two CMS reduced pH of dental plaque in vivo to the same extent as soluble starch, but somewhat less compared with glucose. Lozenges with Purity Gum 40 also lowered plaque pH, although less than when administered as a precooked suspension. The most prominent pH drop was found with a lozenge containing Purity Gum 40-sucrose-glucose, while tablets with gum arabic-maltitol and pectin-gelatine-Lycasin somewhat increased the pH values. To conclude, it is not recommended to exchange gum arabic for CMS in sugar-free lozenges, since the cariogenic properties of the products are negatively affected.     

Effects of chemically modified starches in suspensions and lozenges on pH of human dental plaque

Abstract— The aim was to evaluate chemically modified starches (CMS) from a cariologic point of view as alternatives to gum arabic in sugar-free lozenges. Two commercial CMS, Purity Gum 40 and Capsul, were selected due to their comparatively low availability to alpha-amylase in vitro. Both gelatinized CMS suspensions and lozenges were tested in vivo by measuring plaque pH. The results showed that suspensions of Purity Gum 40 or Capsul were less available to alpha-amylase in vitro than the soluble starch reference. However, the initial phase of amylolysis was comparatively rapid also with CMS. In spite of the slower rate of hydrolysis, suspensions of the two CMS reduced pH of dental plaque in vivo to the same extent as soluble starch, but somewhat less compared with glucose. Lozenges with Purity Gum 40 also lowered plaque pH, although less than when administered as a precooked suspension. The most prominent pH drop was found with a lozenge containing Purity Gum 40-sucrosc-glucose, while tablets with gum arabic-maltitol and pectin-gelatine-Lycasin somewhat increased the pH values. To conclude, it is not recommended to exchange gum arabic for CMS in sugar-free lozenges, since the cariogenic properties of the products are negatively affected.     

Effects on the clinical indices and gingival crevicular fluid enzyme activities of the cyclical regimen of low-dose doxycycline therapy for adult periodontitis

The purpose of this study was to determine the effect of cyclic regimen of low dose doxycycline (20 mg) or placebo therapy following scaling and root planing on clinical parameters and crevicular fluid alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase and elastase activities. Fifteen adults (13 males, 2 females) with moderate to advanced adult periodontitis were recruited for the study. The LDD-treated group (n = 8 subjects) self administered low dose doxycycline b.i.d. (20 mg, p.o.) from time (treatment) to 2 months and then no drug from 2 to 4 months and finally low-dose doxycycline b.i.d. from 4 to 6 months (i.e. "cyclical" regimen). The placebo-treated group (n = 7 subjects) was asked to take placebo capsules (containing inactive filler; i.e. starchflour) b.i.d. according to the same "cyclical" regimen. No differences were found between LDD- and placebo-treated groups regarding any of the clinical parameters and gingival crevicular fluid enzyme activities. The relative attachment gain was significantly improved in both groups. The "cyclical" regimen of low-dose doxycycline was not found to reduce alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase and elastase activities in gingival crevicular fluid of the adult periodontitis patients over a 6-month time period.     

Treatment of peri-implantitis by local delivery of tetracycline. Clinical, microbiological and radiological results

The purpose of this study was to investigate the clinical, microbiological and radiological effects of peri-implantitis therapy by local delivery of tetracycline. In 25 partially edentulous patients, 30 implants with radiographic evidence of circumferential bone loss, and peri-implant probing depths > or =5 mm were treated with polymeric tetracycline HCl-containing fibers. Clinical and microbial parameters were recorded at baseline, and 1, 3, 6, and 12 months (M) after treatment. Standardized radiographs were obtained at baseline, M3, and one year after treatment. Two patients were discontinued from the study after 180 days because of persisting active peri-implantitis with pus formation. The remaining subjects showed a significant decrease of mean peri-implant probing depth from 6.0 to 4.1 mm (M1, P<0.001), which was maintained over 12 months. In comparison to baseline, the bleeding tendency was significantly reduced after one month, and thereafter (P<0.001). No significant recession of the mucosal margin was noted. The radiologically determined distance from the shoulder of the implant to the bottom of the bony defect decreased slightly, but not significantly, from 5.2 to 4.9 mm. At M1, M3 and M6, mean total anaerobic cultivable bacterial counts were significantly lower than at baseline (P<0.001). A significant decrease in frequency of detection was noted for Prevotella intermedia/nigrescens, Fusobacterium sp., Bacteroides forsythus, and Campylobacter rectus (P<0.01). Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Eikenella corrodens had very low baseline frequencies that could not be significantly suppressed further. In conclusion, therapy of peri-implantitis by local delivery of tetracycline had a positive effect on clinical and microbiological parameters.     

Reaction of human sera from juvenile periodontitis, rapidly progressive periodontitis, and adult periodontitis patients with selected periodontopathogens

The levels of serum antibody reactive to selected periodontopathogens were determined in 182 clinically characterized patients: 35 healthy control, 50 juvenile periodontitis, 42 adult periodontitis and 55 rapidly progressive periodontitis. Reactive antibody levels were determined using an enzyme-linked immunosorbent assay with whole cell preparations of Bacteroides gingivalis, Capnocytophaga (Bacteroides) ochraceus, Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans (Y-4) serving as antigens. Increased reactivity to B. gingivalis and F. nucleatum was observed in all three disease groups studied while antibody reactive to A. actinomycetemcomitans was increased in juvenile and rapidly progressive periodontitis. Antibody levels reactive to C. ochraceus in healthy subjects did not differ from those observed in any disease patient groups. Possible implications in the etiology and progression of the diseases coupled with environmental changes which occur in the econiche of the periodontal pocket are described.