Systematic review of the in vitro effects of statins on oral and perioral microorganisms

Statins are medications administered orally and are widely used for lowering the blood cholesterol level. The aim of this study was to investigate the effects of orally administered statins on microorganisms infecting oral and perioral tissues. We performed a systematic review of published studies of the in vitro antimicrobial effects of statins on bacteria, viruses, and fungi, and searched PubMed, Web of Science, Cochrane Central, and Google scholar. Studies show that most statins exhibit antimicrobial effects against various oral microorganisms. Simvastatin is most effective against the periodontal pathogens Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, and against most dental plaque bacteria, including Streptococcus mutans. Statins also exhibit antiviral properties against human cytomegalovirus, hepatitis B virus, and hepatitis C virus, and have antifungal properties against Candida albicans, Aspergillus fumigatus, and Zygomycetes spp. There were notable differences in the minimum inhibitory concentrations (MICs) between different studies, which may be attributed to differences in study design. Further studies are warranted to ascertain if statins can be solubilized so that patients, who have been prescribed statins for cardiovascular diseases, can use the medication as a swish and swallow, giving patients the added benefit of the antimicrobial action topically in the mouth against infectious oral diseases.     

Antimicrobial effects of various endodontic irrigants on selected microorganisms

Aim This study was undertaken to determine the antimicrobial effect of various endodontic irrigants against six selected microorganisms
Methodology Staphylococcus aureus , Enterococcus faecalis , Streptococcus salivarius , Str. pyogenes , Escherichia coli and Candida albicans were included in the study. Pre-sterilized Whatman paper discs, 6 mm in diameter and soaked with the test solution, were prepared and placed onto the previously seeded agar Petri plates. Each plate was incubated aerobically. A zone of inhibition was recorded for each plate and the results were analysed statistically.
Results 5.25% NaOCl was effective against all test microorganisms with a substantial zone of inhibition. Saline was always ineffective. Decreased concentration of NaOCl significantly reduced its antimicrobial effect. Cresophene showed a significantly larger ( P  > 0.05) average zone of inhibition compared to the other experimental irrigants. Alcohol had smaller but not significantly different zones of inhibition than chlorhexidine.
Conclusions 5.25% NaOCl was superior in its antimicrobial abilities compared with other irrigants used. A reduced concentration of NaOCl (0.5%) resulted in significantly decreased antimicrobial effects. When compared with 21% alcohol, 0.5% NaOCl and 2% chlorhexidine, paramonochlorophenol (cresophene) showed a greater antimicrobial effect.     

Susceptibility of oral bacteria to Melaleuca alternifolia (tea tree) oil in vitro

The in vitro activity of Melaleuca alternifolia (tea tree) oil against 161 isolates of oral bacteria from 15 genera was determined. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) ranged from 0.003 to 2.0% (v/v). MIC90 values were 1.0% (v/v) for Actinomyces spp., Lactobacillus spp., Streptococcus mitis and Streptococcus sanguis, and 0.1% (v/v) for Prevotella spp. Isolates of Porphyromonas, Prevotella and Veillonella had the lowest MICs and MBCs, and isolates of Streptococcus, Fusobacterium and Lactobacillus had the highest. Time kill studies with Streptococcus mutans and Lactobacillus rhamnosus showed that treatment with > or = 0.5% tea tree oil caused decreases in viability of >3 log colony forming units/ml after only 30 s, and viable organisms were not detected after 5 min. These studies indicate that a range of oral bacteria are susceptible to tea tree oil, suggesting that tea tree oil may be of use in oral healthcare products and in the maintenance of oral hygiene.     

The antimicrobial activity of essential oils and essential oil components towards oral bacteria

A method for reproducibly determining minimal inhibitory concentrations and minimal bactericidal concentrations of plant extracts towards fastidiously and facultatively anaerobic oral bacteria, predicated upon measurements of optical densities in microtitre plate wells, was devised. The antimicrobial properties of some botanical oils were surveyed; of these, Australian lea tree oil, peppermint oil, and sage oil proved to be the most potent essential oils, whereas thymol and eugenol were potent essential oil components.     

口腔治疗区微生物分布及构成的研究

目的了解口腔内科治疗区微生物的主要分布及菌种构成情况。方法牙椅后、治疗台、距治疗台2 m处及近墙壁处分别放置普通琼脂平板及牛心脑浸出液培养基(BHI)平板,用自然沉降法收集5 min,进行需氧与兼性厌氧菌培养,分离鉴定。结果治疗台与距治疗台2 m处菌株数差异有显著性(P<0.01),牙椅后与治疗台、距治疗台2 m处与近墙处菌株数差异无显著性(P>0.05)。诊室内菌种构成主要为:链球菌60.79%,凝固酶阴性葡萄球菌14.2%,肠球菌7.95%。结论操作者前后区域微生物分布浓度高于远离操作区域,须加强职业防护。     

Efficacy of ozone on survival and permeability of oral microorganisms

In the present study, we examined the effect of ozonated water on oral microorganisms and dental plaque. Almost no microorganisms were detected after being treated with ozonated water (4 mg/l) for 10 s. To estimate the ozonated water-treated Streptococcus mutans, bacterial cells were stained with LIVE/DEAD BacLight Bacterial Viability Kit. Fluorescence microscopic analysis revealed that S. mutans cells were killed instantaneously in ozonated water. Some breakage of ozonated water-treated S. mutans was found by electron microscopy. When the experimental dental plaque was exposed to ozonated water, the number of viable S. mutans remarkably decreased. Ozonated water strongly inhibited the accumulation of experimental dental plaque in vitro. After the dental plaque samples from human subjects were exposed to ozonated water in vitro, almost no viable bacterial cells were detected. These results suggest that ozonated water should be useful in reducing the infections caused by oral microorganisms in dental plaque.     

3种树脂基托试件微生物黏附的研究

目的比较BPS注塑树脂、热凝基托树脂和不碎胶树脂表面的微生物黏附能力。方法将BPS注塑树脂、热凝基托树脂和不碎胶树脂试件进行微生物体外黏附实验,采用菌落形成单位计数法测定血链球菌、黏性放线菌和白色假丝酵母菌黏附量的大小。结果血链球菌和白色假丝酵母菌黏附实验中,培养24、48、168h后,热凝基托树脂组与BPS注塑树脂组和不碎胶树脂组间微生物黏附量差异有统计学意义（P〈0.001）,BPS注塑树脂组和不碎胶树脂组间微生物黏附量差异无统计学意义（P〉0.05）。在黏性放线菌黏附实验中,培养24h时,热凝基托树脂组和BPS注塑树脂组间微生物黏附量差异有统计学意义（P〈0.05） 培养48、168h时,热凝基托树脂组与不碎胶树脂组和BPS注塑树脂组间微生物黏附量差异有统计学意义（P〈0.05）。结论BPS注塑树脂和不碎胶树脂较热凝基托树脂更能减少血链球菌、黏性放线菌和白色假丝酵母菌在其表面的黏附。     

The action of thymol on oral bacteria

Several effects of thymol, a plant-derived antimicrobial agent, on Porphyromonas gingivalis, Selenomonas artemidis and Streptococcus sobrinus were examined. The extremely rapid efflux of intracellular constituents evoked by thymol is consistent with its postulated membranotropic effects. Correlations between leakage-inducing concentrations of thymol and minimal inhibitory concentrations and minimal bactericidal concentrations suggest that membrane perforation is a principal mode of action of this substance. The thymol-induced decline in intracellular ATP in S. sobrinus appears to be entirely attributable to leakage, whereas in P. gingivalis thymol may also inhibit ATP-generating pathways. Relative changes in the transmembrane potential of resting cells of S. sobrinus pulsed with glucose are as sensitive to thymol as is leakage from this organism. The effects of thymol on transmembrane potential are probably secondary to those arising from leakage of intracellular substances.     

Control of microorganisms in vitro by calcium hydroxide pastes

AIM: The aim of this study was to determine the influence of vehicles on the antimicrobial efficiency of calcium hydroxide. METHODOLOGY: A total of 588 size 50 sterile absorbent paper points, were immersed in various microbial suspensions for 3 min. The points were then placed on Petri dishes and covered with intracanal dressings containing calcium hydroxide: Ca(OH)2 + saline; Ca(OH)2 + camphorated paramonochlorophenol; Ca(OH)2 + 1% chlorhexidine solution: Ca(OH)2 + 3% sodium lauryl sulphate; Ca(OH)2 + Otosporin. After 1 min, 48 and 72 h and 7 days, 147 absorbent paper cones were removed from contact with the intracanal dressings and individually transported and immersed in 5 mL of Letheen Broth, followed by incubation at 37 degrees C for 48 h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1-mL inoculum obtained from the Letheen Broth was transferred to 5 mL of BHI, and incubated at 37 degrees C for 48 h. Bacterial growth was again evaluated by turbidity of the culture medium. Positive BHI tubes were selected and inocula were spread on the surface of BHI agar and incubated at 37 degrees C for 48 h. Gram staining of the BHI growth and from colonies growing on BHI agar was carried out. RESULTS: An antimicrobial effect occurred after 48 h on the cultures of S. mutans, E. faecalis, S. aureus, P aeruginosa, B. subtilis, C. albicans and a mixed culture, irrespective of the intracanal dressing. CONCLUSIONS: Under the conditions of this study, the various vehicles associated with calcium hydroxide pastes did not influence the time required for microbial inactivation.     

Combination effects of baicalein with antibiotics against oral pathogens

Background

Baicalein is one of the major flavonoids in Scutellaria baicalensis Georgi, which has long been used in Asia as herbal medicine. Several biological effects of baicalein, such as antiviral, anti-inflammatiom, anti-hepatotoxicity, and anti-tumour properties, have been reported.

Objective and design

In this study, the antibacterial activities of baicalein were investigated in combination with ampicillin and/or gentamicin against oral bacteria.

Results

Baicalein was determined with MIC and MBC values ranging from 80 to 320 and 160 to 640 μg/mL against oral bacteria. The range of MIC₅₀ and MIC₉₀ were 20–160 μg/mL and 80–320 μg/mL, respectively. The combination effects of baicalein with antibiotics were synergistic (FIC index <0.375–0.5 and FBCI <0.5) against oral bacteria. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 1–6 h of treatment with the MIC₅₀ of baicalein, regardless of whether it was administered alone or with ampicillin or gentamicin.

Conclusion

These results suggest that baicalein combined with other antibiotics may be microbiologically beneficial and not antagonistic.     

The effects of periodontal therapy on serum antibody (IgG) levels to plaque microorganisms

The influence of periodontal therapy on serum antibody titers to selected periodontal disease-associated microorganisms was assessed in 23 patients having chronic inflammatory periodontal disease (CIPD). The immunoglobulin G (IgG) titers were determined by the microELISA technique in serum samples obtained prior to treatment; following a hygienic phase which included scaling, root planing, and oral hygiene instruction; following surgical treatment; and one year and two years following hygienic phase (maintenance phase). Considerable individual variability existed in the magnitude of immune response to specific bacterial preparations. Significant reductions in the mean antibody titers were seen to A. viscosus, S. sanguis, F. nucleatum, S. sputigena, B. gingivalis, B. intermedius, B. melaninogenicus, T. vincentii, and T. denticola by the end of the second year of maintenance. There was no consistent response to Capnocytophaga. When individual patient responses were examined, 6 of the 23 were found to have elevated titers to at least one of the microorganisms in the interval between pretreatment and the end of the hygienic phase; however, in all but one case, the titers at the end of the second year of maintenance were below pretreatment levels. Antibody levels to bacteria such as S. sanguis were modified during therapy. This would indicate that immune responses to microbes not generally considered to be "periodontal pathogens" may be modified by adjuvant activity associated with subgingival plaque or changes in the environment of the sulcus and that subsequent changes in titer do not necessarily reflect a role of that microorganism in the disease process.     

The inhibitory action of fatty acids on oral bacteria

Saturated and unsaturated fatty acids and fatty acid derivatives were examined for their growth-inhibitory effects towards three selected oral bacteria: Porphyromonas gingivalis, Selenomonas artemidis , and Streptococcus sobrinus. Of the 45 compounds surveyed, only one, myristoleic acid, was inhibitory towards S. artemidis at a concentration <100 μg/ml. cis -Hexadecenoic and cis -octadecenoic acids were generally inhibitory towards P. gingivalis and S. sobrinus , but there was no correlation between the position of the double bond and the minimum inhibitory concentration. Supra-minimum inhibitory concentrations of palmitoleic acid did not promote leakage of intracellular materials from either P. gingivalis or S. sobrinus , nor was l - iso -leucine uptake by S. sobrinus inhibited. Fatty acids and derivatives were also examined for prospective synergistic or antagonistic interactions with thymol vis-à-vis growth inhibition of the test strains. Laurie acid and myristic acid each behaved synergistically with thymol to inhibit the growth of at least one test strain, whereas cis -10-heptadecenoic acid and thymol were noticeably antagonistic towards the growth of S. sobrinus.     

In vitro antibacterial effects of the crude extracts of Sophora alopecuroides against oral microorganisms

Sophora alopecuroides is widely used in Mongolian traditional medicine. The antimicrobial effects of the methanolic and aqueous extracts of its roots against Streptococcus mutans, Streptococcus sobrinus and Staphylococcus aureus were examined in vitro. Four fractions were obtained from methanol extract and labeled as Fractions-1, 2, 3, and 4. The MIC's and MBC's of the crude extracts of Sophora alopecuroides were determined, and bacterial cell growth curves in the presence of Fractions-1, 3, and 4 were drawn. Among the methanolic extracts, the extracts of Fractions-1, 3, and 4 possessed strong inhibitory effect on the growth of mutans streptococci and S. aureus. Fraction-2 and the aqueous extracts of S. alopecuroides had weak antibacterial activities. Thus, S. alopecuroides would be useful for the suppression of oral pathogens, and has potential for use in the prevention of dental caries and treatment of diseases caused by S. aureus.     

Effects of Nidus Vespae extract and chemical fractions on the growth and acidogenicity of oral microorganisms

Nidus Vespae is the honeycomb of Polistes Olivaceous (De Geer), P. Japonicus Saussure, and Parapolybiavaria Fabricius. It is known to have a number of pharmacological effects, including antimicrobial, anti-inflammatory, anti-virus, anti-tumor and anesthetic properties. The present study evaluated the antimicrobial activity and acid inhibition properties of extracts and chemical fractions of Nidus Vespae. The raw material was first extracted using 95% ethanol/water. Subsequent fractions were prepared from this extract using cyclohexane/ethyl acetate, petroleum ether/ethyl acetate, and chloroform/methanol. For the antimicrobial activity assays, minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined using the microdilution method. The chloroform/methanol (Chl/MeOH) fraction showed the highest antibacterial activities with a MIC of 8-16mg/ml and an MBC of 16-32mg/ml. In addition, the extract and chemical fractions of Nidus Vespae showed a remarkable capacity for inhibiting the acid production of common oral bacteria at sub-MIC concentrations. Sub-MIC levels of the petroleum ether/ethyl acetate fraction significantly inhibited acid production by Streptococcus mutans ATCC 25175. The significant antiacidogenic activity demonstrated by Nidus Vespae shows it to be a promising source of novel anticariogenic agents.     

Effect of critical surface tension on retention of oral microorganisms

Abstract – The effect of critical surface tension on the initial retention of microorganisms from unstimulated human saliva was tested in a flow cell system. Prior to each experiment the total numbers and the morphotypes of microorganisms present in saliva were recorded. The test surfaces were prepared to display known increasing critical surface tensions, as verified and standardized by contact angle measurements. Surfaces of initially low (20–22 mN/m), medium (35–38 mN/m) and high (>50 mN/m) critical surface tension were exposed to saliva at a flow rate of 1 ml/min. Microbiota and biofilm material associated with the test surface after 15 min of salivary exposure, were then subjected to standard detachment forces, by introducing a cell-free rinsing fluid at two different shear rates. Both the attachment and the detachment phases were executed at room temperature or 37°C. The retained population was counted in three different zones of the test surfaces with a light microscope and statistically tested for correlation to the main variables (critical surface tension, flow rate and temperature) and interactions. Retention success was significantly dependent on the initial critical surface tension and the flow rate. Surfaces of medium critical surface tension, representative of human tooth surfaces and most restorative dental materials, retained the highest numbers of microorganisms in comparison with the other surfaces tested, with no statistically verified selectivity in proportions of retained coccoid and rodshaped microorganisms for any surface. A 30-fold increase of the flow rate resulted in a 70–80% reduction of the retention success, with a higher relative number of cocci present on all the test surfaces. These results demonstrate that initial retention of microorganisms to surfaces is non-specific with regard to morphotypes, but is strongly related both to the mechanical removal forces and the surface energetic state of the solid surface exposed. Retention of microbial populations at interfaces might, advance selection of the critical surface tensions and predicted if shear forces at given sites are known.     

Antimicrobial activity of garlic,tea tree oil,and chlorhexidine against oral microorganisms

OBJECTIVE: To compare the antimicrobial activity of tea tree oil, garlic, and chlorhexidine solutions against oral microorganisms. METHOD: The five-week study consisted of thirty subjects. The first week was considered baseline. All subjects used a control solution (second week), and were randomly divided into the three groups (third week): G1-0.12% chlorhexidine; G2 - 2.5% garlic (Allium sativum, L.); and G3 - 0.2% tea tree oil (Melaleuca alternifolia). Dishes containing blood agar and Mitis Salivarius Bacitracin agar (MSB) were inoculated with the subjects' saliva (collected twice a week). Total microorganisms and mutans streptococci were counted in blood agar and MSB, respectively. RESULTS: Chlorhexidine and garlic groups showed antimicrobial activity against mutans streptococci, but not against other oral microorganisms. The tea tree oil group showed antimicrobial activity against mutans streptococci and other oral microorganisms. Maintenance of reduced levels of microorganisms was observed only for garlic and tea tree oil during the two consecutive weeks (fourth and fifth). Unpleasant taste (chlorhexidine 40%, tea tree oil 30%, garlic 100%), burning sensation (chlorhexidine 40%, tea tree oil 60%, garlic 100%), bad breath (chlorhexidine 40%, tea tree oil 20%, garlic 90%), and nausea (chlorhexidine 0%, tea tree oil 10%, garlic 30%) were reported. CONCLUSION: Garlic and tea tree oil might be an alternative to chlorhexidine.     

壳聚糖对几种口腔常见致病菌的体外抑制作用

目的:研究不同分子量及不同浓度的壳聚糖对口腔常见致病菌的体外抑制作用。方法:采用纸片药敏试验,检测不同分子量及不同浓度壳聚糖(浓度为2.0%,1.5%,1.0%,0.5%)在pH6.5时对金黄色葡萄球菌、白色念珠菌、幽门螺杆菌、牙龈卟啉单胞菌和变形链球菌的抑菌环直径;测定不同处理方法对其抑菌效果的影响。组间比较采用随机区组化设计方差分析、完全随机设计方差分析及t检验。结果:不同分子量壳聚糖在pH值6.5时对金黄色葡萄球菌、白色念珠菌、幽门螺杆菌、牙龈卟啉单胞菌、变形链球菌均有抑制作用,但多以小分子量的抑菌作用最好(变形链球菌以大分子量最好)(P<0.05,0.01);且随浓度的增加,抑菌作用增强(P<0.05);经高温处理的壳聚糖抑菌作用稳定,与对照组比较差异无显著性(P>0.05)。结论:壳聚糖在pH6.5条件下对口腔常见致病菌有抑制作用。     

常用可摘局部义齿支架材料表面微生物粘附的实验研究

［摘要］ 目的 研究变异链球菌和白色念珠菌对3种口腔常用金属材料的粘附性,为临床选择合适的材料提供理论依据。方法 选取最常用做可摘局部义齿支架材料的3种金属——钴铬合金、Vitallium 2000材料、纯钛,分别制成尺寸为20 mm×10 mm×2 mm的试件,每组各6个。将各组试件抛光,并保证各组间粗糙度无明显差异。选取变异链球菌和白色念珠菌作为实验菌株,制成菌悬液,分别放入试件进行48 h的粘附实验,取出试件后冲洗、震荡、培养,采用菌落形成计数法(CFU)测定微生物表面粘附量。结果 粘附48 h后,试件表面变异链球菌和白色念珠菌的粘附数量均为钴铬合金>纯钛>Vitallium 2000材料 (P＜0.05)。结论 Vitallium 2000材料与钴铬合金和纯钛相比,粘附微生物的数量最少,值得应用推广。     

淫羊藿对口腔各矿化组织破骨细胞性骨吸收的体外实验研究

目的 探讨中药淫羊藿抑制破骨细胞性骨吸收的作用。方法 体外分离、培养兔破骨细胞，与玻片及灭活牙片共同培养，加入不同浓度淫羊藿注射液。HE、原位末端标记染色玻片上的破骨细胞，观察其形态结构的改变，并观察破骨细胞在牙片上形成的吸收陷窝数目及面积的变化。结果 HE染色可见用药组破骨细胞胞质浓缩，核固缩深染，部分细胞出现核分裂。原位末端标记结果显示，用药组破骨细胞胞质皱缩，胞核呈棕褐色，胞质淡杂。提示淫羊藿可诱导破骨细胞凋亡，抑制骨吸收。用药组与非用药组破骨细胞凋亡率差异有显著性，吸收陷窝数目、面积差异也有显著性，随浓度增加抑制作用增强。结论 淫羊藿可诱导破骨细胞凋亡，抑制骨吸收，并随浓度增加抑制作用增强。