Antibacterial activity of mulberry extracts and purified fractions against oral pathogenic bacteria

OBJECTIVES

This study aimed to isolate antibacterial compounds active against periodontopathic bacteria from mulberry (Morus alba) leaves.

METHODS

The acetone-soluble fraction of mulberry leaves was extracted from the oil layer by oil/water separation. The extract was purified using silica gel open-column chromatography. The minimum inhibitory concentration (MIC) of the crude extract or purified fractions against Porphyromonas gingivalis was measured at each step.

RESULTS

The MIC of the crude extract against P. gingivalis was 62.5-125 μg/mL. The fractions showing activity against P. gingivalis were designated Cf K and Cf P. The MICs of Cf K against P. gingivalis, Fusobacterium nucleatum, Prevotella intermedia, and Streptococcus mutans were 6.25 μg/mL, 25 μg/mL, 12.5 μg/mL, and 12.5 μg/mL, respectively. In contrast, the MICs of Cf P against P. gingivalis, F. nucleatum, P. intermedia, and S. mutans were 25.0 μg/mL, >50 μg/mL, 50 μg/mL, and 12.5-25.0 μg/mL, respectively.

CONCLUSIONS

Mulberry leaves contain antibacterial components against periodontopathic bacteria such as P. gingivalis, F. nucleatum, and P. intermedia.

Microbiological Effects of Sodium Hypochlorite/-Amino Acids and Cross-linked Hyaluronic Acid Adjunctive to Non-surgical Periodontal Treatment

PURPOSE

To investigate the microbiological outcomes obtained with either subgingival debridement (SD) in conjunction with a gel containing sodium hypochlorite and amino acids followed by subsequent application of a cross-linked hyaluronic acid gel (xHyA) gel, or with SD alone.

MATERIALS AND METHODS

Forty-eight patients diagnosed with stages II-III (grades A/B) generalised periodontitis were randomly treated with either SD (control) or SD plus adjunctive sodium hypochlorite/amino acids and xHyA gel (test). Subgingival plaque samples were collected from the deepest site per quadrant in each patient at baseline and after 3 and 6 months. Pooled sample analysis was performed using a multiplex polymerase chain reaction (PCR)-based method for the identification of detection frequencies and changes in numbers of the following bacteria: Aggregatibacter actinomycetemcomitans (A.a), Porphyromonas gingivalis (P.g), Tannerella forsythia (T.f), Treponema denticola (T.d), and Prevotella intermedia (P.i).

RESULTS

In terms of detection frequency, in the test group, statistically significant reductions were found for P.g, T.f, T.d and P.i (p < 0.05) after 6 months. In the control group, the detection frequencies of all investigated bacterial species at 6 months were comparable to the baseline values (p > 0.05). The comparison of the test and control groups revealed statistically significant differences in detection frequency for P.g (p = 0.034), T.d (p < 0.01) and P.i (p = 0.02) after 6 months, favouring the test group. Regarding reduction in detection frequency scores, at 6 months, statistically significant differences in favour of the test group were observed for all investigated bacterial species: A.a (p = 0.028), P.g (p = 0.028), T.f (p = 0.004), T.d (p <0.001), and P.i (p = 0.003).

CONCLUSIONS

The present microbiological results, which are related to short-term outcomes up to 6 months post-treatment, support the adjunctive subgingival application of sodium hypochlorite/amino acids and xHyA to subgingival debridement in the treatment of periodontitis.

Personalized and Defect-Specific Antibiotic-Laden Scaffolds for Periodontal Infection Ablation

Periodontitis compromises the integrity and function of tooth-supporting structures. Although therapeutic approaches have been offered, predictable regeneration of periodontal tissues remains intangible, particularly in anatomically complex defects. In this work, personalized and defect-specific antibiotic-laden polymeric scaffolds containing metronidazole (MET), tetracycline (TCH), or their combination (MET/TCH) were created via electrospinning. An initial screening of the synthesized fibers comprising chemo-morphological analyses, cytocompatibility assessment, and antimicrobial validation against periodontopathogens was accomplished to determine the cell-friendly and anti-infective nature of the scaffolds. According to the cytocompatibility and antimicrobial data, the 1:3 MET/TCH formulation was used to obtain three-dimensional defect-specific scaffolds to treat periodontally compromised three-wall osseous defects in rats. Inflammatory cell response and new bone formation were assessed by histology. Micro-computerized tomography was performed to assess bone loss in the furcation area at 2 and 6 weeks post implantation. Chemo-morphological and cell compatibility analyses confirmed the synthesis of cytocompatible antibiotic-laden fibers with antimicrobial action. Importantly, the 1:3 MET/TCH defect-specific scaffolds led to increased new bone formation, lower bone loss, and reduced inflammatory response when compared to antibiotic-free scaffolds. Altogether, our results suggest that the fabrication of defect-specific antibiotic-laden scaffolds holds great potential toward the development of personalized (i.e., patient-specific medication) scaffolds to ablate infection while affording regenerative properties.

Antimicrobial efficacy of photodynamic therapy and light-activated disinfection on contaminated zirconia implants: An in vitro study

BACKGROUND

We aimed to evaluate the antimicrobial efficacy of photodynamic therapy (PDT) and light-activated disinfection (LAD) on zirconia dental implants contaminated with three bacterial species and investigate if the PDT and LAD cause implant surface alterations.

METHODS

Seventy-two zirconia dental implants were contaminated with a bacterial suspension of Prevotella intermedia, Actinomyces actinomycetemcomitans, and Porphyromonas gingivalis. The implants were subsequently randomly divided into four groups (n = 12 dental implants/each) according to the decontamination protocol: Group 1 (PDT1) - PDT (660 nm, 100 mW) with toluidine blue; Group 2 (PDT2) - PDT (660 nm, 100 mW) with phenothiazine chloride dye; Group 3 (LAD) - light emitting diode (LED) with toluidine blue; and Group 4 (TB) - toluidine blue without the application of light. Implants in the positive control (PC) group were treated with a 0.2% chlorhexidine-based solution, and implants assigned to the negative control (NC) group did not undergo any treatment. Each implant was then placed in tubes containing phosphate buffered saline (PBS) and vortexed for 60 s to remove the remaining bacteria from the implant surface. After 10-fold serial dilutions, 30 μl of the suspension was plated on Brucella agar plates. After 72 h, the colony forming units (CFU) were counted. Distinctive colonies were confirmed with MALDI Biotyper. The implants were analyzed using scanning electron microscope (SEM) to evaluate the possible surface alterations due to PDT or LAD.

RESULTS

All study groups had significant reductions in the number of CFUs compared with the NC (p < 0.05). PDT1, the PDT2, and the LAD groups had the largest bacterial reduction with respect to each bacterial species separately and the total bacterial count, and they were more efficient compared with the TB group (p < 0.05). SEM analysis did not reveal any alterations of the implant surface after the treatment procedures.

CONCLUSION

Both PDT protocols and LAD showed high and equal effectiveness in decontamination of zirconia dental implants.

Surface treatment of implant materials with antimicrobial nanoparticulates

This study analyzed nanostructured silver vanadate (AgVO3) films on certain substrate surfaces found in dental implant devices in order to see if these films promote antimicrobial activity. Enamel and glaze vehicles were used to apply the nanomaterial (0.0% [control], 2.5%, 5.0%, and 10.0% concentrations) on 3 substrates (280 specimens per substrate): polytetrafluoroethylene (PTFE), polyacetal, and acrylic resin. An agar diffusion method was performed in triplicate to determine the antimicrobial activity against 8 microorganisms. Physical behavior and morphologic properties were also analyzed. The growth of Pseudomonas aeruginosa, Escherichia coli, Streptococcus mutans, Enterococcus faecalis, and Staphylococcus aureus was inhibited with the application of AgVO3. For Candida albicans, Porphyromonas gingivalis, and Prevotella intermedia, no antimicrobial activity was observed. Except for S mutans, the type of substrate did not influence the microbiologic results. The glaze showed greater antimicrobial efficacy against S aureus, E faecalis, and S mutans than did the enamel vehicle (P < 0.05). Films with 10% AgVO3 showed greater antimicrobial activity (P < 0.05). The choice of substrate or vehicle did not influence the surface roughness (P > 0.05); however, the application of 10% AgVO3 caused greater surface change (P < 0.05). The application of the nanomaterial did not influence the surface hardness of substrates when compared with the control group (P > 0.05). The use of the glaze as a vehicle provided higher hardness values (P < 0.05).

Inhibition of malodorous gas formation by oral bacteria with cetylpyridinium and zinc chloride

OBJECTIVE

The antimicrobial efficacy of zinc- (ZnCl₂) and cetylpyridinium-chloride (CPC) and their inhibition capacity on volatile sulfur compound (VSC) production by oral bacterial strains were investigated.

DESIGN

Minimum inhibitory concentrations (MIC) and growth curves were determined for ZnCl₂, CPC, and CPC with ZnCl₂ solutions against eight oral microorganisms (Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, Tannerella forsythia, Staphylococcus aureus and Streptococcus mutans) known to be involved in the pathophysiology of both halitosis and periodontal disease. Gas chromatography was applied to measure VSCs (H₂S, CH₃SH, (CH₃)₂S) production levels of each strains following exposure to the solutions.

RESULTS

ZnCl₂ and CPC effectively inhibited growth of all eight strains. ZnCl₂ was generally more effective than CPC in suppressing bacterial growth excluding A. actinomycetemcomitans, P. intermedia, and T. forsythia. Synergism between CPC and ZnCl₂ was shown in A. actinomycetemcomitans. The MIC for CPC was significantly lower than ZnCl₂. VSC production was detected in five bacterial strains (A. actinomycetemcomitans, F. nucleatum, P. gingivalis, T. denticola, and T. forsythia). Each bacterial strain showed unique VSCs production profiles. H₂S was produced by F. nucleatum, P. gingivalis, and T. denticola, CH₃SH by all five strains and (CH₃)₂S by A. actinomycetemcomitans, F. nucleatum, P. gingivalis, and T. denticola. Production of CH₃SH, the most malodorous component among the three major VSCs from mouth air was evident in F. nucleatum and T. forsythia.

CONCLUSION

Both ZnCl₂ and CPC effectively inhibit bacterial growth causative of halitosis and periodontal disease, resulting in a direct decrease of bacterial VSCs production.

In Vitro Effects of Polyphosphate against Prevotella intermedia in Planktonic Phase and Biofilm

Polyphosphate (polyP) has gained a wide interest in the food industry due to its potential as a decontaminating agent. In this study, we examined the effect of sodium tripolyphosphate (polyP3; Na5P3O10) against planktonic and biofilm cells of Prevotella intermedia, a major oral pathogen. The MIC of polyP3 against P. intermedia ATCC 49046 determined by agar dilution method was 0.075%, while 0.05% polyP3 was bactericidal against P. intermedia in time-kill analysis performed using liquid medium. A crystal violet binding assay for the assessment of biofilm formation by P. intermedia showed that sub-MICs of polyP3 significantly decreased biofilm formation. Under the scanning electron microscope, decreased numbers of P. intermedia cells forming the biofilms were observed when the bacterial cells were incubated with 0.025% or higher concentrations of polyP3. Assessment of biofilm viability with LIVE/DEAD staining and viable cell count methods showed that 0.05% or higher concentrations of polyP3 significantly decreased the viability of the preformed biofilms in a concentration-dependent manner. The zone sizes of alpha-hemolysis formed on horse blood agar produced by P. intermedia were decreased in the presence of polyP3. The expression of the genes encoding hemolysins and the genes of the hemin uptake (hmu) locus was downregulated by polyP3. Collectively, our results show that polyP is an effective antimicrobial agent against P. intermedia in biofilms as well as planktonic phase, interfering with the process of hemin acquisition by the bacterium.

Antimicrobial effectiveness of cetylpyridinium chloride and zinc chloride-containing mouthrinses on bacteria of halitosis and peri-implant disease

PURPOSE

To clarify the antimicrobial efficacy of zinc chloride (ZnCl2) and cetylpyridinium chloride (CPC) by testing their impact on the growth of seven bacterial strains known to be involved in the pathophysiology of both peri-implant disease and halitosis-Staphylococcus aureus, Streptococcus mutans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Treponema denticola, and Tannerella forsythia.

MATERIALS AND METHODS

A time-response growth curve was obtained. Commercial mouthrinses with CPC, ZnCl2, or both were added to the media in a final concentration of 0.25% CPC, 2.5% ZnCl2, and 2.5% ZnCl2 with 0.25% CPC.

RESULTS

Both CPC and ZnCl2 effectively inhibited the growth of almost all bacterial strains tested except T denticola. ZnCl2 was generally more effective in suppressing bacterial growth than CPC. ZnCl2 with CPC showed the greatest inhibitory activities on almost all strains of bacterial growth except for P gingivalis and T denticola, followed by ZnCl2, then CPC, thus suggesting the possibility of a synergistic effect of the two agents. P gingivalis exhibited a different pattern because ZnCl2 showed the most significant inhibitory effect. CPC did not show growth inhibitory effects on T denticola, but ZnCl2 did.

CONCLUSION

Zinc and CPC effectively inhibit bacterial growth that causes both halitosis and peri-implant disease. The effect is even more powerful when applied in combination.

Comparison of Riboflavin and Toluidine Blue O as Photosensitizers for Photoactivated Disinfection on Endodontic and Periodontal Pathogens In Vitro

Photoactivated disinfection has a strong local antimicrobial effect. In the field of dentistry it is an emerging adjunct to mechanical debridement during endodontic and periodontal treatment. In the present study, we investigate the effect of photoactivated disinfection using riboflavin as a photosensitizer and blue LED light for activation, and compare it to photoactivated disinfection with the widely used combination of toluidine blue O and red light. Riboflavin is highly biocompatible and can be activated with LED lamps at hand in the dental office. To date, no reports are available on the antimicrobial effect of photoactivated disinfection using riboflavin/blue light on oral microorganisms. Planktonic cultures of eight organisms frequently isolated from periodontal and/or endodontic lesions (Aggregatibacter actinomycetemcomitans, Candida albicans, Enterococcus faecalis, Escherischia coli, Lactobacillus paracasei, Porphyromonas gingivalis, Prevotella intermedia and Propionibacterium acnes) were subjected to photoactivated disinfection with riboflavin/blue light and toluidine blue O/red light, and survival rates were determined by CFU counts. Within the limited irradiation time of one minute, photoactivated disinfection with riboflavin/blue light only resulted in minor reductions in CFU counts, whereas full kills were achieved for all organisms when using toluidine blue O/red light. The black pigmented anaerobes P. gingivalis and P. intermedia were eradicated completely by riboflavin/blue light, but also by blue light treatment alone, suggesting that endogenous chromophores acted as photosensitizers in these bacteria. On the basis of our results, riboflavin cannot be recommended as a photosensitizer used for photoactivated disinfection of periodontal or endodontic infections.

[Antibacterial effect of the carboxymethyl chitosan zinc peptide on several periodontal pathogens in vitro]

OBJECTIVE

To determine the antimicrobial effects of carboxymethyl chitosan zinc (CMC-Zn(+)) and CMC-Zn(+)-peptide (CMC-Zn(+)-P) on four kinds of periodontal pathogens.

METHODS

Dilution method was used to determine the minimum inhibitory concentration (MIC) of CMC-Zn(+) for Porphyromonas gingivalis (Pg), Actinobacillusactinomycetemcomitans (Aa), Prevotella intermedia (Pi) and Actinomyces viscosus (Av). The antimicrobial characters of CMC-Zn(+) and CMC-Zn(+)-P on these four kinds of pathogens were evaluated by disk diffusion method.

RESULTS

The MIC of CMC-Zn(+) for Pg, Aa, Pi and Av was 0.312 5%, 0.156 25%, 0.156 25% and 0.078 125% respectively. Significant antimicrobial effects were improved along with the increased concentration of CMC-Zn(+) and CMC-Zn(+)-P (P < 0.01), while the best antimicrobial concentrations of both CMC-Zn(+) and CMC-Zn(+)-P were 5%. The antimicrobial effect of CMC-Zn(+)-P was better than that of CMC-Zn(+) on the same kind of periodontal pathogen (P < 0.01). CMC-Zn(+)-P showed different antimicrobial effects on the four periodontal pathogens (Av > Aa > Pi or Av > Aa > Pg, P < 0.01).

CONCLUSIONS

CMC-Zn(+) and CMC-Zn(+)-P have inhibition effect on Pg, Aa, Pi and Av, and the best antibacterial concentration was 5%. The CMC-Zn(+)-P has better antibacterial effect than CMC-Zn(+) on Pg, Aa, Pi and Av.

Antimicrobial effects of citrus sinensis peel extracts against periodontopathic bacteria: an in vitro study

BACKGROUND

Use of plant extracts and phytochemicals with known antimicrobial properties may have great significance in therapeutic treatments.

OBJECTIVE

To assess the in vitro antimicrobial potential and also determine the minimum inhibitory concentration (MIC) of Citrus sinensis peel extracts with a view of searching a novel extract as a remedy for periodontal pathogens.

MATERIALS AND METHODS

Aqueous and ethanol (cold and hot) extracts prepared from peel of Citrus sinensis were screened for in vitro antimicrobial activity against Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia, using agar well diffusion method. The lowest concentration of every extract considered as the minimal inhibitory concentration (MIC) values were determined for both test organisms. Confidence level and level of significance were set at 95% and 5% respectively.

RESULTS

Prevotella intermedia and Porphyromonas gingivalis were resistant to aqueous extracts while Aggregatibacter actinomycetemcomitans was inhibited at very high cncentrations. Hot ethanolic extracts showed significantly higher zone of inhibition than cold ethanolic extract. Minimum inhibitory concentration of hot and cold ethanolic extracts of Citrus sinensis peel ranged between 12-15 mg/ml against all three periodontal pathogens.

CONCLUSIONS

Both extracts were found sensitive and contain compounds with therapeutic potential. Nevertheless, clinical trials on the effect of these plants are essential before advocating large-scale therapy.

[Effects of cetylpyridinium chloride buccal tablets on halitosis induced by oral conditions]

OBJECTIVE

To investigate the effect of cetylpyridinium chloride buccal tablets on halitosis induced by oral conditions.

METHODS

With Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum as the testing bacteria, the minimal inhibitory concentration (MIC) of cetylpyridinium chloride buccal tablets was determined using minute amount serial dilution test. The production of volatile sulfur compounds (VSCs) was measured using sulfide detector halimeter in the anaerobic bacteria culture at 4 and 8 h after addition of the tablets. The effect of the tablets in suppressing odor production by mouth-borne halitosis bacteria was assessed using cysteine challenge test in healthy volunteers, and the effectiveness was evaluated by measuring the reduction in VSCs production and the duration of the effect.

RESULTS

Cetylpyridinium chloride buccal tablets inhibited the growth of all the 3 bacteria. The tablets obviously inhibited VSCs production by the 3 bacteria with a effect similar to chlorhexidine. Compared with distilled water gargle, the buccal tablets significantly reduced cysteine-induced VSCs production level in the healthy volunteers (P<0.05), and the effect lasted for 230 min.

CONCLUSION

Cetylpyridinium chloride tablets can obviously suppress bacteria responsible for oral halitosis and produce good effects in the treatment of halitosis induced by oral conditions.

Identification of organic acids in Cichorium intybus inhibiting virulence-related properties of oral pathogenic bacteria

The low molecular mass (LMM) extract of Cichorium intybus var. silvestre (red chicory) has been shown to inhibit virulence-linked properties of oral pathogens including Streptococcus mutans, Actinomyces naeslundii and Prevotella intermedia. In the present study HPLC-DAD-ESI/MS(2) was used to investigate the compounds contained in this extract for their anti-virulence activity. The extract contained a number of components, including oxalic, succinic, shikimic and quinic acids, which interfere with the growth and virulence traits (i.e., biofilm formation, adherence to epithelial cells and hydroxyapatite) of oral pathogens involved in gingivitis and tooth decay. Succinic and quinic acid seem to be the most potent, mainly by interfering with the ability of oral pathogens to form biofilms (either through inhibition of their development or promotion of their disruption). Our findings suggest that one or more of these compounds may modulate plaque formation in vivo, which is a prerequisite for the development of both caries and gingivitis.

The evaluation of enamel matrix derivative on subgingival microbial environment in non-surgical periodontal therapy

INTRODUCTION AND OBJECTIVE

Recent in vitro studies indicate that enamel matrix derivative (EMD) could modulate the growth of periodontopathogens. The aim of the presented study was an analysis of the influence of EMD on the presence of Porphyromonas and Prevotella bacteria in the periodontal pockets of patients with chronic periodontitis in non-surgical periodontal therapy.

MATERIALS AND METHODS

The studies were conducted on 20 patients. The condition of the periodontium was evaluated by clinical indexes: API. SBI. PD. CAL before and 3 months after the therapy in two selected quadrants. The material was collected for investigation. The periodontopathogens were cultured and identified. Two days after EMD-scaling root planing (SRP) was applied into the pockets.

RESULTS

In the group of patients under investigation before the EMD application the presence of P. gingivalis was found in 6 patients and P. intermedia in 8 patients. After root planing and EMD application no periodontopathogens were identified in those patients either in the periodontal pockets treated with EMD or in the periodontal pockets free from EMD (control). In the statistical analysis of changes in clinical indexes, the application of SRP and SRP combined with EMD was proved to significantly influence the improvement of the clinical state. However, no significant differences between the individual parameters were found in either group.

CONCLUSIONS

The SRP is an effective method of limiting the development of periopathogens in periodontal pockets. The non-surgical therapy with EMD does not change the clinical parameters significantly, compared with the SRP. Simultaneously, the application of EMD inhibits the development of periopathogens, such as Porphyromonas gingivalis and Prevotella.

Inhibitory activity of green tea (Camellia sinensis) extract on some clinically isolated cariogenic and periodontopathic bacteria

OBJECTIVE

To determine the in vitro inhibitory activity of green tea extract on some clinically isolated cariogenic and periodontopathic bacteria.

MATERIALS AND METHODS

Twenty strains of each of Streptococcusmutans, Aggregatibacteractinomycetemcomitans, Porphyromonasgingivalis, and Prevotellaintermedia were isolated from carious teeth and periodontal pockets of patients with dental caries and periodontal diseases. Green tea extract was prepared by aqueous extraction method and diluted from 50 to 1.56 mg/ml. Standard techniques of agar disk diffusion and broth microdilution assays were applied for qualitative and quantitative determinations of antibacterial activity of green tea extract on each isolates.

RESULTS

All clinical isolates of S. mutans (100%) were sensitive to green tea extract at concentrations 6.25, 12.5, 25, and 50 mg/ml producing inhibition zones ranging from 10 to 38 mm. All periodontopathic isolates (A. actinomycetemcomitans, n = 20, P. intermedia, n = 20, and P. gingivalis, n = 20) (100%) tested were sensitive to 12.5, 25, and 50 mg/ml of this extract. The minimal inhibitory concentration of green tea extract for S. mutans was 3.28 ± 0.7 mg/ml and for A. actinomycetemcomitans 6.25, for P. gingivalis and P. intermedia 12.5 mg/ml.

CONCLUSIONS

Our findings showed that green tea extract exhibited strong antibacterial activity on S. mutans,A. actinomycetemcomitans,P. gingivalis and P. intermedia and therefore may be used in mouthwashes or dentifrices for prevention of dental caries and periodontal diseases.

Antimicrobial activity of sodium hypochlorite in endodontics

One of the major objectives in endodontic therapy is to disinfect the entire root canal system. This goal may be achieved using mechanical instrumenation and chemical irrigation in conjunrction with medication of the root canal between treatment sessions. Microorganisms and their by-products are considered to be the major cause of pulpal and periradicular patholic. In order to reduce or eliminate bacteria and popular tissue remnants, the use of various irrigation solution during treatment have been suggested. Sodium hypochlorite (NaOCI), the most common irrigant, is an excellent nonspecific proteolytic and antimicrobial agent. The purpose of this paper is to review the antimicrobial activity of sodium hypochlorite.

Effects of fruit and vegetable low molecular mass fractions on gene expression in gingival cells challenged with Prevotella intermedia and Actinomyces naeslundii

Low molecular mass (LMM) fractions obtained from extracts of raspberry, red chicory, and Shiitake mushrooms have been shown to be an useful source of specific antibacterial, antiadhesion/coaggregation, and antibiofilm agent(s) that might be used for protection towards caries and gingivitis. In this paper, the effects of such LMM fractions on human gingival KB cells exposed to the periodontal pathogens Prevotella intermedia and Actinomyces naeslundii were evaluated. Expression of cytokeratin 18 (CK18) and β4 integrin (β4INT) genes, that are involved in cell proliferation/differentiation and adhesion, and of the antimicrobial peptide β2 defensin (HβD2) in KB cells was increased upon exposure to either live or heat-killed bacteria. All LMM fractions tested prevented or reduced the induction of gene expression by P. intermedia and A. naeslundii depending on the experimental conditions. Overall, the results suggested that LMM fractions could modulate the effects of bacteria associated with periodontal disease in gingival cells.

Effects of mushroom and chicory extracts on the physiology and shape of Prevotella intermedia, a periodontopathogenic bacterium

Contrary to the common assumption that food has a negative impact on oral health, research has shown that several foods contain a number of components with antibacterial and antiplaque activity. These natural compounds may be useful for improving daily oral hygiene. In this study we evaluate the mode of antimicrobial action of fractions of mushroom and red chicory extracts on Prevotella intermedia, a periodontopathogenic bacterium. The minimal inhibitory concentration corresponded to 0.5x compared to the natural food concentration for both extracts. This concentration resulted in a bacteriostatic effect in mushroom extract and in a slightly bactericidal effect in chicory extract. Cell mass continued to increase even after division stopped. As regards macromolecular synthesis, DNA was almost totally inhibited upon addition of either mushroom or chicory extract, and RNA to a lesser extent, while protein synthesis continued. Cell elongation occurred after septum inhibition as documented by scanning electron microscopy and cell measurement. The morphogenetic effects are reminiscent of the mode of action of antibiotics such as quinolones or β-lactams. The discovery of an antibiotic-like mode of action suggests that these extracts can be advantageously employed for daily oral hygiene in formulations of cosmetic products such as mouthwashes and toothpastes.

The antiplaque efficacy of pomegranate mouthrinse

OBJECTIVE

to evaluate the effect of a pomegranate-containing mouthrinse on plaque, determine whether it has any adverse effects, and evaluate its antibacterial properties against selected periodontopathogens in vitro.

METHOD AND MATERIALS

thirty periodontally healthy volunteers, randomly divided into three groups, refrained from all mechanical oral hygiene measures for 4 days and used one of the randomly assigned mouthrinses (A, pomegranate; B, chlorhexidine; or C, distilled water [placebo]) twice daily. The Plaque Index (PI) was assessed at days 0 and 5. Adverse effects were also evaluated. Pomegranate extract was tested against Aggregatibacter actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), and Prevotella intermedia (P.i.).

RESULTS

in all groups, the PI significantly increased from the baseline to day 5 (P < .1). The pomegranate mouthrinse created no adverse effects. There was a statistically significant difference (P < .05) between the chlorhexidine and placebo rinse and the pomegranate and placebo rinse, but no statistically significant difference was found between the chlorhexidine and pomegranate rinse with respect to the PI. Pomegranate extract showed inhibition of all three strains of periodontopathogens at various concentrations.

CONCLUSION

these results indicate that the pomegranate mouthrinse has an antiplaque effect. Pomegranate extract is efficacious against A.a., P.g., and P.i. strains in vitro. Pomegranate mouthrinse should be explored as a long-term antiplaque rinse with prophylactic benefits.

Photodynamic therapy in periodontal therapy: microbiological observations from a private practice

In recent years, the combination of laser light and photosensitizer known as photodynamic therapy (PDT) has been used in periodontal therapy. However, there are not enough clinical studies to fully evaluate the effects of PDT on the periodontal tissues. This microbiological study examined the effects of PDT on the periodontal bacteria in combination with scaling and root planing (SRP) in the same group of patients by randomly selecting PDT or SRP for use in different quadrants of the mouth. For the present study, PDT was compared with a diode laser (980 nm) and an Nd:YA G laser (1,064 nm). Microbiological samples were examined and evaluated over a period of three months. Significant bacterial reduction has been observed in all cases. The diode laser with SRP presented long-term positive results, while PDT showed a significant bacteria reduction during the entire observation period.

Hyaluronan-containing mouthwash as an adjunctive plaque-control agent

PURPOSE

Hyaluronan, commonly known as hyaluronic acid, has been shown to have anti-inflammatory action, bacteriostatic effect and antioxidant properties, thus making its use as a long-term anti-plaque and anti-gingivitis agent an appealing proposition. The aim of the present study was to evaluate the efficacy of 0.025% hyaluronan-containing mouthwash in comparison with 0.2% chlorhexidine and a water-based mouthwash and also to evaluate its antibacterial efficacy on isolated strains of periodontopathogens.

MATERIALS AND METHODS

Forty-five volunteers in a hospital setting were recruited. A single-blinded, parallel design, randomised controlled trial was carried out and the 4-day plaque re-growth model was used to study the efficacy of the three mouthwashes. Microbiological and clinical evaluation was performed by culturing and using dental indices, respectively. The three mouthwashes used in the present study were commercially available 0.025% sodium hyaluronate, 0.2% chlorhexidine and a water-based rinse (negative control). Effects of the three mouthwashes were tested on the growth of isolated strains of Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa) and Prevotella intermedia (Pi).

RESULTS

In vitro, hyaluronan had a distinct effect on the growth of Aa and Pi with no effect on the growth of Pg. In vivo, the differences between the individual rinse solutions and the water-based solution showed significantly less plaque regrowth with respect to both chlorhexidine (P = 0.033) and hyaluronan (P = 0.045) when compared to the negative control. The difference between chlorhexidine and hyaluronan was not statistically significant (P = 0.69).

CONCLUSIONS

Hyaluronan (0.025%)-containing mouthwash was comparable to chlorhexidine (0.2%) in inhibiting plaque growth in vivo, and it significantly reduced the growth of Aa and Pi in vitro

Injectable thermosensitive hydrogel based on chitosan and quaternized chitosan and the biomedical properties

A novel injectable thermosensitive hydrogel (CS-HTCC/alpha beta-GP) was successfully designed and prepared using chitosan (CS), quaternized chitosan (HTCC) and alpha,beta-glycerophosphate (alpha,beta-GP) without any additional chemical stimulus. The gelation point of CS-HTCC/alpha beta-GP can be set at a temperature close to normal body temperature or other temperature above 25 degrees C. The transition process can be controlled by adjusting the weight ratio of CS to HTCC, or different final concentration of alpha,beta-GP. The optimum formulation is (CS + HTCC) (2% w/v), CS/HTCC (5/1 w/w) and alpha,beta-GP 8.33% or 9.09% (w/v), where the sol-gel transition time was 3 min at 37 degrees C. The drug released over 3 h from the CS-HTCC/alpha,beta-GP thermosensitive hydrogel in artificial saliva pH 6.8. In addition, CS-HTCC/alpha,beta-GP thermosensitive hydrogel exhibited stronger antibacterial activity towards two periodontal pathogens (Porphyromonas gingivalis, P.g and Prevotella intermedia, P.i). CS-HTCC/alpha, beta-GP thermosensitive hydrogel was a considerable candidate as a local drug delivery system for periodontal treatment.

Antibiotic resistance of periodontal pathogens obtained from frequent antibiotic users

The occurrence of bacterial strains resistant to different antimicrobials is a growing problem in Latin American countries. The aim was to measure the antimicrobial susceptibility of Fusobacterium nucleatum, Prevotella intermedia and Prophyromona gingivalis, isolated from chronic periodontitis patients. Twenty-five patients diagnosed with generalized- moderate or advanced- chronic periodontitis were consecutively recruited from patients attending the Periodontal Specialist Program, Javeriana University, according to specific criteria, including no recent antibiotic consumption. All patients filled out a questionnaire on antibiotic intake. The deepest periodontal pocket in each quadrant was sampled. Pooled samples were mixed, diluted and plated on enriched brucella agar plates. After anaerobic incubation, identification of the target bacteria was performed, based on colony morphology, gram staining, aerotolerance and biochemical reactions (RapID Ana II, Remel, U.S.A.). Following identification, the bacteria were subjected to antimicrobial testing, using amoxicillin, tetracycline, doxycicline, azithromycin and metronidazole (E-test, AbBiodisk, Sweden). The minimal inhibitory concentrations obtained were compared with a reference standard to determine antimicrobial resistance. Amoxicillin-resistant species were tested for beta-lactamase production. Forty-four percent of the patients used antibiotics without any medical prescription, 40% used antibiotics at least once a year. The presence of eleven species was confirmed after a series of biochemical tests: four Fusobacterium nucleatum, five Prevotella intermedia and two Prophyromona gingivalis. All strains were resistant to metronidazole, five were resistant to tetracycline and azithromicin, and two strains were resistant to doxycicline and amoxicillin. The strains resistant to amoxicillin were positive for beta-lactamase production, Antimicrobial resistance, particularly against metronidazole, was a common phenomenon for the bacterial isolates analyzed in this Colombian sample.

Antibacterial activity of [10]-gingerol and [12]-gingerol isolated from ginger rhizome against periodontal bacteria

Ginger (Zingiber officinale Roscoe) has been used widely as a food spice and an herbal medicine. In particular, its gingerol-related components have been reported to possess antimicrobial and antifungal properties, as well as several pharmaceutical properties. However, the effective ginger constituents that inhibit the growth of oral bacteria associated with periodontitis in the human oral cavity have not been elucidated. This study revealed that the ethanol and n-hexane extracts of ginger exhibited antibacterial activities against three anaerobic Gram-negative bacteria, Porphyromonas gingivalis ATCC 53978, Porphyromonas endodontalis ATCC 35406 and Prevotella intermedia ATCC 25611, causing periodontal diseases. Thereafter, five ginger constituents were isolated by a preparative high-performance liquid chromatographic method from the active silica-gel column chromatography fractions, elucidated their structures by nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry and their antibacterial activity evaluated. In conclusion, two highly alkylated gingerols, [10]-gingerol and [12]-gingerol effectively inhibited the growth of these oral pathogens at a minimum inhibitory concentration (MIC) range of 6-30 microg/mL. These ginger compounds also killed the oral pathogens at a minimum bactericidal concentration (MBC) range of 4-20 microg/mL, but not the other ginger compounds 5-acetoxy-[6]-gingerol, 3,5-diacetoxy-[6]-gingerdiol and galanolactone.

Antiplaque/antigingivitis efficacy and safety of a cetylpyridinium chloride/zinc gluconate mucoadhesive gel. Results of a 6-month clinical trial

This article presents the results of a controlled clinical trial evaluating a new at-home treatment to improve gingival health. Designed for overnight application at the gingival margins and in the interproximal spaces, the product is a mucoadhesive gel containing 0.10% cetylpyridinium chloride (CPC) and 0.592% zinc gluconate (ZG). The authors assessed the efficacy and safety of the CPC/ZG gel in adults with low-to-moderate gingival and plaque index scores by comparing clinical and laboratory findings for subjects using the CPC/ZG gel with those for subjects using the control gel (0% CPC and 0.592% ZG). Clinical findings at 3 and 6 months showed statistically significant improvements in two of the three major indices of gingival health in the CPC/ZG group compared with the control group. The performance of the treatment gel was supported by results of microbial analyses of plaque samples.