Porphyromonas Gingivalis Strains Research Articles

Amino acids as wetting agents: surface translocation by Porphyromonas gingivalis

Our understanding of how oral microbiota adapt in response to changes in their surroundings remains limited. This is particularly true of the slow-growing anaerobes that persist below the gum line. Here, we report that the oral anaerobe Porphyromonas gingivalis strain 381 can surface translocate when sandwiched between two surfaces. We show that during movement, this bacterium alters its metabolism, specifically side products of arginine utilization including citrulline and ornithine accumulated in the translocating cells; while arginine, N-acetyl-arginine, and the polyamine putrescine, which is produced from arginine were consumed. In addition, our results indicate that movement requires modification of the surrounding environment via proteolysis, cell dispersion, cell-on-cell rolling, and sub-diffusive cell-driven motility. We also show that production of fimbriae and fimbriae-associated proteins; as well as the regulation of contact-dependent growth inhibition genes, which are known to be involved in self-nonself discrimination, and the type IX secretion system are central to surface translocation. These studies provide a first glimpse into P. gingivalis motility and its relationship to ecological variables.

Assessment of the antimicrobial efficacy of hydroalcoholic fruit extract of cranberry against Socransky complexes and predominant cariogenic, mycotic and endodontic climax communities of the oral cavity: An extensive in-vitro study.

Background and Objective:Contemporary global complementary and alternative practices in dentistry envisage to manipulate the molecules from traditionally used plant derivatives as adjuncts. The aim of this study was to assess the in-vitro antimicrobial efficacy of hydro-alcoholic fruit extract of cranberry against Socransky complexes and predominant cariogenic, mycotic and endodontic climax communities of the oral cavity.Materials and Methods:An extract of Vaccinium macrocarpon was prepared using a hydro-ethanolic solvent (water – 30%: ethanol – 70%) using the standardized maceration protocol. Standard American Type Cell Culture and Microbial Type Culture Collection and Gene Bank strains of Streptococcus mutans, Lactobacillus acidophilus, Candida albicans, Enterococcus faecalis, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were used. The minimum inhibitory concentration was determined by the serial broth dilution. The minimum bactericidal concentration was obtained by subculturing method.Results:The extract showed satisfactory inhibitory and bactericidal effects against all test pathogens.Conclusion:V. macrocarpon can prove to be an adjunct to the existing antimicrobial complexes being routinely used to combat pathogenic oral climax community.

Comparison of different types and sources of chitosan for the treatment of infections in the oral cavity

Various formulation strategies have been investigated for non-invasive delivery of antimicrobials into the oral cavity for the treatment of the oral infections. In general, mucoadhesive polymers have been used to keep the delivery system at the application site for an extended period of time, avoiding the removal of the drug by tongue movement, as well as salivation and swallowing. Chitosan, as a mucoadhesive biopolymer has become a very promising material in development of oral mucosal delivery systems, which can be prepared in various forms such as gels, films, sponges, tablets, micro/nanoparticles. The aim of the present study was to investigate different types of chitosan, with different molecular weight and solubility properties as a delivery system, as well as for its antimicrobial activity against Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Candida albicans strains. For this purpose, gel formulations were prepared using different types of chitosan obtained from animal (crab shell) or non-animal (white mushroom) sources, and chlorhexidine gluconate (Chx), which is widely used in clinical dental practice as an antiseptic oral rinse due to its activity against a wide range of microbial species, was incorporated into the formulations at 0.1 and 0.2% w/v concentrations. Formulations were compared in regard to their flow and bioadhesive properties, in vitro drug release and antifungal/antibacterial activities. The viscosity of the formulations was found to be increased both with the increased concentration as well as with the increased molecular weight of chitosan whilst the drug release became slower. The antimicrobial activity was increased with the increased molecular weight of chitosan. The efficiency of Chx was significantly enhanced in presence of chitosan. Chitosans showed different antimicrobial activity depending on their properties, as well as the type of the strains tested.

An in vitro model of Fusobacterium nucleatum and Porphyromonas gingivalis in single- and dual-species biofilms.

PurposeThe goal of this study was to develop and validate a standardized in vitro pathogenic biofilm attached onto saliva-coated surfaces.MethodsFusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) strains were grown under anaerobic conditions as single species and in dual-species cultures. Initially, the bacterial biomass was evaluated at 24 and 48 hours to determine the optimal timing for the adhesion phase onto saliva-coated polystyrene surfaces. Thereafter, biofilm development was assessed over time by crystal violet staining and scanning electron microscopy.ResultsThe data showed no significant difference in the overall biomass after 48 hours for P. gingivalis in single- and dual-species conditions. After adhesion, P. gingivalis in single- and dual-species biofilms accumulated a substantially higher biomass after 7 days of incubation than after 3 days, but no significant difference was found between 5 and 7 days. Although the biomass of the F. nucleatum biofilm was higher at 3 days, no difference was found at 3, 5, or 7 days of incubation.ConclusionsPolystyrene substrates from well plates work as a standard surface and provide reproducible results for in vitro biofilm models. Our biofilm model could serve as a reference point for studies investigating biofilms on different surfaces.

Identification of Multiple Strains of Porphyromonas gingivalis using Heteroduplex Polymerase Chain Reaction in Varying Severity of Chronic Periodontitis

Aim: Research has demonstrated that there are multiple strains of Porphyromonas gingivalis with varying potency to cause periodontal disease. The current study aims at using heteroduplex polymerase chain reaction (PCR) to detect the strain diversity of P. gingivalis in periodontitis lesions of varying severity in a sample of the Indian population. Materials and Methods: Subgingival plaque samples were collected from 60 individuals with varying severity of chronic periodontitis and 30 individuals with a clinically healthy periodontium. The samples were subjected to PCR analysis to identify P. gingivalis, followed by heteroduplex analysis to identify the strain diversity in a given sample. Bacterial culture was carried out as a comparative standard. Results: Of the 56 samples that were positive for P. gingivalis by PCR, 54 samples yielded eight different heteroduplex patterns. Analysis of these patterns indicated that two strains of P. gingivalis were present in 41 individuals (45.6%) and three strains were present in 13 individuals (14.4%). Detection of P. gingivalis by PCR was significantly more in the periodontitis group as compared to the healthy group. Conclusions: Species-specific PCR and heteroduplex analysis provide a simple and accurate method to analyse the strain diversity of P. gingivalis. P. gingivalis was detected in both healthy periodontal sites as well as sites with periodontitis. The presence of two or three P. gingivalis strains was seen in 60% of the samples.

Development of radiopaque, biocompatible, antimicrobial, micro-particle fillers for micro-CT imaging of simulated periodontal pockets

ObjectivesApproximately 109 bacteria can be harbored within periodontal pockets (PP) along with inflammatory byproducts implicated in the pathophysiology of systemic diseases linked to periodontitis (PD). Calculation of this inflammatory burden has involved estimation of total pocket surface area using analog data from conventional periodontal probing which is unable to determine the three-dimensional (3-D) nature of PP. The goals of this study are to determine the radiopacity, biocompatibility, and antimicrobial activity of transient micro-particle fillers in vitro and demonstrate their capability for 3-D imaging of artificial PP (U.S. Patent publication number: 9814791 B2). MethodsRelative radiopacity values of various metal oxide fillers were obtained from conventional radiography and micro-computed tomography (μCT) using in vitro models. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were used to measure the biocompatibility of calcium tungstate (CaWO4) particles by determination of viable keratinocytes percentage (%) after exposure. After introducing an antibacterial compound (K21) to the radiopaque agent, antimicrobial tests were conducted using Porphyromonas gingivalis (P. gingivalis) and Streptococcus gordonii (S. gordonii) strains and blood agar plates. ResultsCaWO4 micro-particle-bearing fillers exhibited an X-ray radiopacity distinct from tooth structures that enabled 3-D visualization of an artificial periodontal pocket created around a human tooth. MTT assays indicated that CaWO4 micro-particles are highly biocompatible (increasing the viability of exposed keratinocytes). Radiopaque micro-particle fillers combined with K21 showed significant antimicrobial activity for P. gingivalis and S. gordonii. SignificanceThe plausibility of visualizing PP with 3-D radiographic imaging using new radiopaque, biocompatible, transient fillers was demonstrated in vitro. Antibacterial (or other) agents added to this formula could provide beneficial therapeutic features along with the diagnostic utility.

Antimicrobial Effects of Three Different Treatment Modalities on Dental Implant Surfaces

Resolution of peri-implant inflammation and re-osseointegration of peri-implantitis affected dental implants seem to be dependent on bacterial decontamination. The aims of the study were to evaluate the antimicrobial effects of 3 different instrumentations on a micro-textured dental implant surface contaminated with an avirulent or a virulent Porphyromonas gingivalis strain and to determine alterations to the implant surface following instrumentation. Forty-five dental implants (Straumann SLA) were allocated to 3 treatment groups: Er:YAG laser, chitosan brush, and titanium curette (10 implants each) and a positive (10 implants) and a negative (5 implants) control. Each treatment group and the positive control were split into subgroups of 5 implants subsequently contaminated with either the avirulent or virulent P. gingivalis strain. The antimicrobial effect of instrumentation was evaluated using checkerboard DNA-DNA hybridization. Implant surface alterations were determined using a light interferometer. Instrumentation significantly reduced the number of attached P. gingivalis ( P < .001) with no significant differences among groups ( P = .310). A significant overall higher median score was found for virulent compared with avirulent P. gingivalis strains ( P = .007); the Er:YAG laser uniquely effective removing both bacterial strains. The titanium curette significantly altered the implant surface micro-texture. Neither the Er:YAG laser nor the chitosan brush significantly altered the implant surface. The 3 instrumentations appear to have a similar potential to remove P. gingivalis. The titanium curette significantly altered the microstructure of the implant surface.

Differences in survival, virulence and biofilm formation between sialidase-deficient and W83 wild-type Porphyromonas gingivalis strains under stressful environmental conditions

BackgroundPorphyromonas gingivalis is a major causative pathogen of chronic periodontitis. Within the inflammatory microenvironment, there exists extreme pH values, elevated temperatures and oxidative stress. Pathogens adapt to these stressful environmental conditions by regulating the transcription of virulence genes, modifying themselves with macromolecules and by aggregating and entering into a biofilm growth phase. Our previous study showed that the P. gingivalis sialidase can help cells obtain sialic acid from the environment, which is used to modify macromolecules on the surface of P. gingivalis cells. In this study, we compared the survival, virulence factors and biofilm formation of a sialidase-deficient strain (ΔPG0352) and the wild-type P. gingivalis W83 strain under various pH values, temperatures and oxidative stress conditions to identify the roles of sialidase in the adaptation of P. gingivalis to stressful conditions.ResultsCompared to the growth of the P. gingivalis W83 strain, the growth of the △PG0352 was more inhibited by oxidative stress (0.25 and 0.5 mM H2O2) and exhibited greater cell structure damage when treated with H2O2 as assessed by transmission electron microscopy. Both Lys-gingipain (Kgp) and Arg-gingipain (Rgp) activities were lower in the ΔPG0352 than those in the P. gingivalis W83 strain under all the assayed culture conditions. The lipopolysaccharide (LPS) activity of the W83 strain was higher than that of the ΔPG0352 under acidic conditions (pH 5.0), but no differences between the strains were observed under other conditions. Compared to the biofilms formed by P. gingivalis W83, those formed by the ΔPG0352 were decreased and discontinuous under acidic, alkaline and oxidative stress conditions.ConclusionCompared to the P. gingivalis W83 strain, the survival, virulence and biofilm formation of the ΔPG0352 were decreased under stressful environmental conditions.

Gene expression profiling of fimA gene encoding fimbriae among clinical isolates of Porphyromonas gingivalis in response to photo-activated disinfection therapy

BackgroundThe endodontic disinfection therapy majorly aims to eradicate microbial pathogens. Photo-activated disinfection (PAD), also known as antimicrobial photodynamic therapy, is an alternative antimicrobial modality used to control the microorganisms causing endodontic infections. Notably, microorganisms may be exposed to sub-lethal doses of PAD (sPAD), influencing microbial virulence. The present study assessed the effects of sPAD on expression profiling of the gene associated with the biofilm formation being the most essential virulence factor in Porphyromonas gingivalis strain cells that survive the photodynamic reatment in vivo. Materialas and methodsSixteen clinical strains of PAD resistant P. gingivalis that were isolated in vivo, were further photosensitized in vitro with toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) as the photosensitizing agents, which were excited with specific wavelength of light based on the photosensitizer. After evaluating sPAD, its effects on the fimA gene expression were assessed using real-time quantitative reverse transcription PCR (qRT-PCR). ResultsIn this study, maximum values of sPAD against P. gingivalis were 6.25μg/mL TBO at a fluency of 171.87J/cm2, 15.6μg/mL ICG at fluency of 15.6J/cm2, and 25μg/mL MB at fluency of 93.75J/cm2. MB-, TBO-, and ICG-sPAD could cause about 4.6-, 14.4-, and 17.3-fold suppression of fimA expression, respectively. P. gingivalis strains expressed less virulence in cells surviving PAD. ConclusionsIn conclusion, the gene expression profiling was reduced in the bacterial cells, wherein greater reduction was observed for ICG-sPAD than TBO- and MB-sPAD.

In silico Comparison of 19 Porphyromonas gingivalis Strains in Genomics, Phylogenetics, Phylogenomics and Functional Genomics.

Currently, genome sequences of a total of 19 Porphyromonas gingivalis strains are available, including eight completed genomes (strains W83, ATCC 33277, TDC60, HG66, A7436, AJW4, 381, and A7A1-28) and 11 high-coverage draft sequences (JCVI SC001, F0185, F0566, F0568, F0569, F0570, SJD2, W4087, W50, Ando, and MP4-504) that are assembled into fewer than 300 contigs. The objective was to compare these genomes at both nucleotide and protein sequence levels in order to understand their phylogenetic and functional relatedness. Four copies of 16S rRNA gene sequences were identified in each of the eight complete genomes and one in the other 11 unfinished genomes. These 43 16S rRNA sequences represent only 24 unique sequences and the derived phylogenetic tree suggests a possible evolutionary history for these strains. Phylogenomic comparison based on shared proteins and whole genome nucleotide sequences consistently showed two groups with closely related members: one consisted of ATCC 33277, 381, and HG66, another of W83, W50, and A7436. At least 1,037 core/shared proteins were identified in the 19 P. gingivalis genomes based on the most stringent detecting parameters. Comparative functional genomics based on genome-wide comparisons between NCBI and RAST annotations, as well as additional approaches, revealed functions that are unique or missing in individual P. gingivalis strains, or species-specific in all P. gingivalis strains, when compared to a neighboring species P. asaccharolytica. All the comparative results of this study are available online for download at ftp://www.homd.org/publication_data/20160425/.

Effect of photoactivated disinfection using light in the blue spectrum

BackgroundLight in the blue spectrum is well known to cure composites. This in vitro-study was aimed to analyze a potential antimicrobial activity when combined with riboflavin as a photosensitizer. MethodsPhotoactivated disinfection (PAD) using a LED lamp emitting in the blue spectrum for 30s (PAD30) and 60s (PAD60) after application of 0.1% riboflavin was compared with a LED lamp emitting in the red spectrum with the respective photosensitizer (PADred). Killing activity was analyzed against planktonic 14 single species and a 12-species mixture with and without 25% serum. In addition, there was a reduction of viable bacterial counts in single species and a 12-species biofilm was measured after PAD. ResultsGram-positive bacteria were less sensitive to PAD30 and PAD60 than Gram-negatives. PAD60 decreased the counts by more than 3log10cfu in two of five Gram-positive and in six of nine Gram-negative strains, the total viable counts of the mixture were reduced by 1.04±0.46log10cfu. In the presence of 25% serum a decrease by more than 2log10cfu was only found in tests with one Porphyromonas gingivalis strain. PADred killed all included strains except for the 12-species mixture and Eubacterium nodatum. PAD60 reduced the counts in P. gingivalis biofilms by 2–3log10cfu, however there was no activity of PAD60 and PADred on the multi-species biofilm. ConclusionsPAD using LED emitting in the blue spectrum combined with riboflavin is active against periodontopathogenic microbial species but clearly inferior to PADred. Multi-species biofilms are not sensitive to PAD using LED.

Efficacy of 10% whole Azadirachta indica (neem) chip as an adjunct to scaling and root planning in chronic periodontitis: A clinical and microbiological study.

Anti-microbial therapy is essential along with conventional therapy in the management of periodontal disease. Instead of systemic chemical agents, herbal products could be used as antimicrobial agents. Herbal local drug delivery systems are effective alternative for systemic therapy in managing the chronic periodontal disease. In this study, 10% neem oil chip was used as a local drug delivery system to evaluate the efficacy in the periodontal disease management. Twenty otherwise healthy patients with the bilateral periodontal probing depth of 5-6 mm were included in the study. After scaling and root planning (SRP), 10% nonabsorbable neem chip was placed in the pocket in one side of the arch. Other side was done with SRP only. Clinical parameters were recorded on the baseline, 7th day, and 21st day. Plaque samples were obtained for a microbiological study on the baseline and 21st day. Porphyromonas gingivalis strains were seen using quantitative and qualitative polymerase chain reaction assay. All results were statistically evaluated. Clinical parameters showed statistically improved on the neem chip sites and presence of P. gingivalis strains were significantly reduced on the neem chip sites. Hence, 10% neem oil local delivery system delivers desired effects on P. gingivalis. Further research is needed to evaluate the neem oil efficacy on other periodontal pathogens.

Antimicrobial effect of platelet-rich plasma and platelet-rich fibrin.

Platelet concentrates have been extensively used in a variety of medical fields to promote soft- and hard-tissue regeneration. The significance behind their use lies in the abundance of growth factors (GFs) in platelets α-granules that promote wound healing. Other than releasing a pool of GFs upon activation, platelets also have many features that indicate their role in the anti-infective host defense. The aim of this study is to evaluate the antimicrobial activities of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) against periodontal disease-associated bacteria. Blood samples were obtained from ten adult male patients. PRP and PRF were procured using centrifugation. The antimicrobial activity of PRP and PRF was evaluated by microbial culturing using bacterial strains of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. P. gingivalis and A. actinomycetemcomitans were inhibited by PRP but not by PRF. PRP is a potentially useful substance in the fight against periodontal pathogens. This might represent a valuable property in adjunct to the enhancement of tissue regeneration.

Evaluation of antimicrobial activity of orange peel extract against oral biofilm forming organisms: an in vitro microbial study and scanning electron microscopic assessment

Background: To evaluate in vitro antimicrobial activity of orange peel extract, 0.2% chlorhexidine (CHX) and saline against dental biofilm-forming bacteria and their effect on plaque structure under SEM. Methods: Present study included 3 groups; Group A: Orange peel extract; Group B: 0.2% CHX and Group C: Saline. MIC of each group was determined by broth and well diffusion method. Reference strains of Porphyromonas gingivalis ( P.g. ), Prevotella intermedia ( P.i. ) and Aggregatibacter actinomycetemcomitans ( A.a.) were selected as being colonizers in dental biofilm. For SEM analysis, plaque retained orthodontic e-chains were subjected to each group for 60s and studied under SEM. Results: The MIC of Group A by broth diffusion method is 66.66 µg/ml for P. intermedia , 75 µg/ml for P. gingivalis and 33.33 µg/ml for A.a. MIC of Group B was 14.58 µg/ml for P.i., 7.29 µg/ml for P.g. and 20.83 µg/ml for A.a. MIC of Group C was 83.33 µg/ml for A.a. while P.i. and P.g. showed resistance to Group C. The determination of MIC by well diffusion showed increase in clear zone diameter with increasing concentrations. Greater zone of inhibition was seen in Group B with statistical significance for all 3 microorganisms. Morphologic changes in the SEM study showed maximum change in the surface characteristics and loss of adhesion of the clusters of microorganisms subjected to Group B. Conclusions: CHX and orange peel extract exhibited notable anti-microbial activity against biofilm organisms, but at varying concentrations. The plaque samples subjected to orange peel extract showed slightly shrunken and coarse form indicating its ability to disrupt the plaque biofilm.

Regulator of Calcineurin 1 in Periodontal Disease.

Nuclear factor of activated T-cells (NFAT) and NF-kB pathway associated processes are involved in the pathogenesis of various inflammatory disorders, for example, periodontal disease. The activation of these pathways is controlled by the regulator of calcineurin 1 (RCAN1). The aim of this study was to elucidate the role of RCAN1 in periodontal disease. Healthy and inflamed periodontal tissues were analyzed by immunohistochemistry and immunofluorescence using specific rabbit polyclonal anti-RCAN1 antibodies. For expression analysis human umbilical vein endothelial cells (HUVEC) were used. HUVEC were incubated for 2 h with Vascular Endothelial Growth Factor (VEGF) or with wild type and laboratory strains of Porphyromonas gingivalis (P. gingivalis). Expression analysis of rcan1 and cox2 was done by real time PCR using specific primers for rcan1.4 and cox2. The expression of rcan1 was found to be significantly suppressed in endothelial cells of chronically inflamed periodontal tissues compared to healthy controls. Rcan1 and cox2 were significantly induced by VEGF and wild type and laboratory P. gingivalis strains. Interestingly, the magnitude of the rcan1 and cox2 induction was strain dependent. The results of this study indicate that RCAN1 is suppressed in endothelial cells of chronically inflamed periodontal tissues. During an acute infection, however, rcan1 seems to be upregulated in endothelial cells, indicating a modulating role in immune homeostasis of periodontal tissues.

Varying hemin concentrations affect Porphyromonas gingivalis strains differently

Porphyromonas gingivalis requires heme to grow, however, heme availability and concentration in the periodontal pockets vary. Fluctuations in heme concentration may affect each P. gingivalis strain differently, however, this was never fully demonstrated. Here, we elucidated the effects of varying hemin concentrations in representative P. gingivalis strains. Throughout this study, representative P. gingivalis strains [FDC381 (type I), MPWIb-01 (type Ib), TDC60 (type II), ATCC49417 (type III), W83 (type IV), and HNA99 (type V)] were used and grown for 24 h in growth media under varying hemin concentrations (5 × , 1 × , 0.5 × , 0.1 × ). Samples were lysed and protein standardized. Arg-gingipain (Rgp), H2O2, and superoxide dismutase (SOD) levels were subsequently measured. We focused our study on 24 h-grown strains which excluded MPWIb-01 and HNA99. Rgp activity among the 4 remaining strains varied with Rgp peaking at: 1 × for FDC381, 5 × for TDC60, 0.5 × for ATCC49417, 5 × and 0.5 × for W83. With regards to H2O2 and SOD amounts: FDC381 had similar H2O2 amounts in all hemin concentrations while SOD levels varied; TDC60 had the lowest H2O2 amount at 1 × while SOD levels became higher in relation to hemin concentration; ATCC49417 also had similar H2O2 amounts in all hemin concentrations while SOD levels were higher at 1 × and 0.5 × ; and W83 had statistically similar H2O2 and SOD amounts regardless of hemin concentration. Our results show that variations in hemin concentration affect each P. gingivalis strain differently.

Synteny Based Analysis to Proffer a Non-drug Resistant Target Against Porphyromonas gingivalis

Porphyromonas gingivalis is an anerobic, gram negative, bacterium which is a natural inhabitant of oral microbiome. Under unhealthy oral hygiene conditions the bacterium becomes highly destructive (photobiont) and leads to periodontitis (inflammation of periodontium). Several drugs like chlorhexidine, monocycline effectively reduce the viability of biofilms formed by Porphyromonas gingivalis but, it is impossible to destroy biofilms completely. As the bacterium evolves continuously it develops drug resistance due to events like horizontal gene transfer and its biofilm mode of living. Therefore no drug is very efficient in treating Periodontitis. We have done an Insilco Synteny based comparative analysis to find a druggable target which remains unchanged in various Porphyromonas gingivalis strains. Dipeptidylaminopeptidase has been identified one such potential target which is responsible for virulence in Porphyromonas gingivalis, and is functionally and structurally conserved. Therefore, according to best knowledge of authors a drug developed against this target will be effective in treating periodontitis caused by all evolved forms of bacterium.

Antimicrobial Activity of Protamine against Oral Microorganisms.

Protamine is an arginine-rich polycationic protein extracted from sperm cells of vertebrates including fishes such as salmon. The purpose of this study was to investigate the suppressive effects of protamine on the growth of oral pathogens for possible usage in dental materials. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by the microdilution method. Twelve strains of oral viridans streptococci, Actinomyces naeslundii, Actinomyces odontolyticus, Enterococcus faecalis, Lactobacillus acidophilus, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis and Candida albicans were suppressed by protamine. MIC and MBC values were between 0.009 ～ 20 mg/mL and 0.019 ～ 80 mg/mL, respectively. The bactericidal activities of protamine against susceptible bacterial species were dependent on the concentration of protamine and incubation time. Based on the results of this study, protamine would be a useful compound for the development of antimicrobial agents against oral pathogens in dental materials.

Phototoxic effect of visible blue light on Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis in patients with chronic periodontitis (An in-vitro study)

The aim of this study was to determine phototoxic effect of visible blue light on anaerobic periodontal pathogens namely Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Materials and methods: Strains of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were isolated from pockets of systemically healthy patients aged between 35-55 years old with pocket depths of 5-6 mm, the bacteria cultured on special blood Agar plates solid media, then subjected to visible blue light emitted from commercially available light cure devise (LED curing light); that emits blue light (400-500nm) of 1000mw energy at different periods of time exposures, then the CFU of each plate was measured by direct colony count with the aid of open CFU software after 48hours of anaerobic incubation. Results: There was a decrease in CFU for both microorganisms as we proceeded from zero, 20, 40 and 60 seconds of blue light exposure. Conclusion: there was a phototoxic effect for the visible blue light emitted from the light curing device against the anaerobic periodontal pathogens.

Formulation and evaluation of antimicrobial activity of Morus alba sol-gel against periodontal pathogens

Background: Periodontitis has a multifactorial etiology, with primary etiologic agents being pathogenic bacteria that reside in the subgingival area. Recent advances in the field of alternative medicine introduced various herbal products for the treatment of periodontitis. Aim: To assess and compare the antimicrobial activity of Morus alba sol-gel with chlorhexidine sol-gel against ATCC standard strains of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia. Materials and Methods: Crude extract of Morus alba leaves was prepared by Soxhlet method by using ethanol as a solvent. Phytochemical screening of the crude extract of M. alba was performed to check the various chemical constituents. M. alba sol-gel and chlorhexidine sol-gel were formulated using Pluronic f127 and Pluronic f108 and compared for their antimicrobial activity. The minimum inhibitory concentration of both the gels was performed using agar well diffusion technique. Results: The minimum inhibitory concentration of M. alba sol-gel and chlorhexidine sol-gel against A. actinomycetemcomitans is 19 and 17 mm, T. forsythia is 12 and 21 mm, and P. gingivalis is 16 and 18 mm, respectively. Conclusion: Both M. alba and chlorhexidine sol-gel exhibited potent antimicrobial activity against periodontal pathogens.