Oral Pathogenic Bacteria Research Articles

Ursolic acid inhibits multi-species biofilms developed by Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii

ObjectiveThe current study aimed to assess the antimicrobial activity of ursolic acid (UA) against multi-species biofilms formed by Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii, as well as to measure its biocompatibility. MethodsCrystal violet staining, CFU counting, CCK-8 assays and scanning electron microscopy (SEM) were applied to investigate the effect of UA on multi-species biofilms. UA’s effect on exopolysaccharides (EPS) production was measured using confocal laser scanning microscopy (CLSM) and the anthrone-sulfuric acid method. Fluorescent in situ hybridization (FISH) was applied to visualize and quantify the microbial composition of multi-species biofilms. Quantitative real-time PCR (qRT-PCR) was used to measure the expression of virulence genes of S. mutans, S. sanguinis, and S. gordonii under UA treatment. Moreover, CCK-8 assays were performed to evaluate its cytotoxicity against human oral keratinocytes (HOKs) and human gingival epithelial cells (HGEs). ResultsThe results showed that UA had significant antimicrobial activity against common oral streptococci. UA also reduced the EPS synthesis of oral streptococci and suppressed gtf genes’ expression. In addition, UA reduced the proportion of S. mutans in multi-species biofilms. Besides, UA had low cytotoxicity against HOKs and HGEs. ConclusionsUA exhibited antibiofilm activity against oral pathogenic bacteria and had the potential to be used in dental caries treatment.

Berberine ameliorates the LPS-induced imbalance of osteogenic and adipogenic differentiation in rat bone marrow-derived mesenchymal stem cells.

Lipopolysaccharide (LPS) from oral pathogenic bacteria is an important factor leading to alveolar bone absorption and the implant failure. The present study aimed to evaluate the modulation of berberine hydrochloride (BBR) on the LPS-mediated osteogenesis and adipogenesis imbalance in rat bone marrow-derived mesenchymal stem cells (BMSCs). Cell viability, osteoblastic and adipogenic differentiation levels were measured using the Cell Counting Kit-8 assay, alkaline phosphatase (ALP) staining and content assay, and oil red O staining, respectively. Reverse transcription-quantitative PCR and immunoblotting were used to detect the related gene and protein expression levels. In undifferentiated cells, BBR increased the mRNA expression levels of the osteoblastic genes (Alp, RUNX family transcription factor 2, osteocalcin and secreted phosphoprotein 1) but not the adipogenic genes (fatty acid binding protein 4, Adipsin and peroxisome proliferator-activated receptorγ). LPS-induced osteoblastic gene downregulation, adipogenic gene enhancement and NF-κB activation were reversed by BBR treatment. In osteoblastic differentiated cells, decreased ALP production by LPS treatment was recovered with BBR co-incubation. In adipogenic differentiated cells, LPS-mediated lipid accumulation was decreased by BBR administration. The mRNA expression levels of the pro-inflammatory factors (MCP-1, TNF-α, IL-6 and IL-1β) were increased by LPS under both adipogenic and osteoblastic conditions, which were effectively ameliorated by BBR. The actions of BBR were attenuated by compound C, suggesting that the role of BBR may be partly due to AMP-activated protein kinase activation. The results demonstrated notable pro-osteogenic and anti-adipogenic actions of BBR in a LPS-stimulated inflammatory environment. This indicated a potential role of BBR for bacterial infected-related peri-implantitis medication.

New Approaches to the Control of Pathogenic Oral Bacteria

구강에는 700여 종의 미생물이 부유성 세균(planktonic cells)으로 있거나 치아 표면에 부착하여 바이오필름(biofilms)을 형성하고 있으며 구강 바이오필름(oral biofilms)과 관련된 대표적인 구강질환에는 치아우식증과 치주질환이 있다. 구강 세균은 타액의 흐름, 숙주의 항균 단백질, 영양소의 가용성 및 pH 변화, 항생제, 방부제 등의 영향을 받고 있지만 바이오필름이 형성되면 바이오필름은 물리적으로 두꺼운 층을 이루고 있기 때문에 구강 세균은 이와 같은 구강 내부의 환경적 스트레스에 저항할 수 있을 뿐만 아니라 외부 물질의 침투가 어렵고 바이오필름 내 세포간 상호작용을 통해 유전자 변이가 일어나기 때문에 부유성 세균보다 항생제에 대한 저항성이 1,000배 정도 높다. 따라서 구강 세균의 바이오필름 형성을 억제하거나 제거하면 보다 효과적으로 세균 감염에 의한 구강질환을 예방하거나 치료할 수 있을 것이다. 특히 구강 바이오필름은 여러 세균이 모여서 바이오필름을 형성하는 특징을 가지고 있기 때문에 세포간 신호전달체계인 정족수 감지(quorum sensing)는 구강 바이오필름을 제어할 수 있는 목표점이 될 수 있다. 이외에도 구강세균의 알칼리 생성 기질인 아르기닌을 이용하여 구강 미생물의 분포를 건강한 치아와 유사한 환경으로 전환하거나 S. mutans의 glucosyltransferase 분비를 억제하여 비수용성의 글루칸 형성을 억제함으로써 바이오필름 형성을 억제하는 방법도 구강 바이오필름을 제어할 수 있는 목표점이 될 수 있다. 이처럼 구강 내 병원성 세균의 사멸을 유도하기 보다는 구강 세균의 바이오필름 형성을 억제하거나 제거하는 방법은 치아우식증을 비롯한 구강질환을 선택적으로 예방하거나 치료할 수 있는 새로운 전략이 될 것이다.

Tooth brushing using toothpaste containing theaflavins reduces the oral pathogenic bacteria in healthy adults

The online version contains supplementary material available at 10.1007/s13205-021-02699-7.

Antimicrobial Photodynamic Treatment with Mother Juices and Their Single Compounds as Photosensitizers.

The potent antimicrobial effects of antimicrobial photodynamic therapy (aPDT) with visible light plus water-filtered infrared-A irradiation and natural compounds as photosensitizers (PSs) have recently been demonstrated. The aim of this study was to obtain information on the antimicrobial effects of aPDT with mother juices against typical cariogenic oral Streptococcus pathogens in their planktonic form and determine its eradication potential on total human salivary bacteria from volunteers. Mother juices of pomegranate, bilberry, and chokeberry at different concentrations were used as PSs. The unweighted (absolute) irradiance was 200 mW cm−2, applied five minutes. Planktonic cultures of Streptococcus mutans and Streptococcus sobrinus and total mixed bacteria from pooled saliva of volunteers were treated with aPDT. Up to more than 5 log10 of S. mutans and S. sobrinus were killed by aPDT with 0.4% and 0.8% pomegranate juice, 3% and 50% chokeberry juice, and 12.5% bilberry juice (both strains). Concentrations of at least 25% (pomegranate) and >50% (chokeberry and bilberry) eradicated the mixed bacteria in saliva samples. This pilot study has shown that pomegranate mother juice is superior to the berry juices as a multicomponent PS for killing pathogenic oral bacteria with aPDT.

Non-alcoholic steatohepatitis caused by oral bacteria

Liver damage caused by excessive nutrient intake without a history of alcohol consumption is collectively referred to as nonalcoholic fatty liver disease, while progressive inflammatory changes and fibrosis of the liver are defined as non-alcoholic steatohepatitis (NASH). Recently, the mechanisms by which oral bacteria are involved in systemic diseases have been uncovered, though few reports of their association with fatty liver have been reported. This review aimed to summarize relevant current knowledge related to the detailed mechanisms of oral bacteria-associated NASH development. Recent reports have noted detection of highly pathogenic oral bacteria in NASH patients. In addition, NASH-like symptoms have been reported following administration of oral bacteria in a mouse model of obesity induced by a high-fat diet. These results reveal important details regarding the mechanism of NASH development by oral bacterial infection.

Fabrication of an injectable iron (III) crosslinked alginate-hyaluronic acid hydrogel with shear-thinning and antimicrobial activities

The combination of alginate, hyaluronic acid and multivalent ions have been reported to form alginate-hyaluronic acid ionic-crosslinking hydrogels for biomedical applications. However, injectable alginate-hyaluronic acid ionic-crosslinking hydrogels with satisfactory shear-thinning property have rarely been reported. In this study, we successfully developed an ionic-crosslinked alginate-hyaluronic acid hydrogel by simple assembly of alginate-hyaluronic acid mixture and Fe3+ complex. This hydrogel could fully recover within seconds after damaged, while displayed shear thinning behavior and good injectability which were contributed by the reversible and dynamic metal-ligand interactions formed via ferric ions and carboxyl groups of the polymers. Moreover, the local degradation of this hydrogel giving the hydrogel sustained ferric ions release property, of which led to potential long-term antibacterial activities against multiple types of bacteria including gram-negative Escherichia coli and gram-positive Staphylococcus aureus, as well as representative oral pathogenic bacteria Streptococcus mutans and Porphyromonas gingivalis.

Lactobacillus reuteri AN417 cell-free culture supernatant as a novel antibacterial agent targeting oral pathogenic bacteria

Lactobacillus reuteri AN417 is a newly characterized probiotic strain. The activity of AN417 against oral pathogenic bacteria is unknown. We investigated the antibacterial activity of cell-free L. reuteri AN417 culture supernatant (LRS) against three oral pathogens: Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mutans. P. gingivalis and F. nucleatum have been implicated in periodontal disease, whereas S. mutans causes dental caries. Exposing these oral pathogenic bacteria to LRS significantly reduced their growth rates, intracellular ATP levels, cell viability, and time-to-kill. The minimal inhibitory volume of LRS was 10% (v/v) against P. gingivalis, 20% (v/v) for F. nucleatum, and 30% (v/v) for S. mutans. LRS significantly reduced the integrity of biofilms and significantly suppressed the expression of various genes involved in P. gingivalis biofilm formation. The L. reuteri AN417 genome lacked genes encoding reuterin, reuteran, and reutericyclin, which are major antibacterial compounds produced in L. reuteri strains. LRS treated with lipase and α-amylase displayed decreased antibacterial activity against oral pathogens. These data suggest that the antibacterial substances in LRS are carbohydrates and/or fatty acid metabolites. Our results demonstrate that LRS has antimicrobial activity against dental pathogenic bacteria, highlighting its potential utility for the prevention and treatment of P. gingivalis periodontal disease.

Novel Amides Derivative with Antimicrobial Activity of Piper betle var. nigra Leaves from Indonesia.

Piper betle var. nigra is a tropical plant closely related to the common piper. P. betle has also been dubbed a promising source of natural antioxidants in herbal health products, antibacterial, antifungal, antimalarial, cytotoxic activity against the cancer cell lines K562 and HL-60, and antileishmanial. The aim of this study to observation Antimicrobial activity and isolation of chemical compound. The antimicrobial activity of P. betle extract was performed by well diffusion method against two oral pathogenic bacteria (Streptococcus mutans and Streptococcus sanguinis) and opportunistic pathogenic yeast (Candida albicans). The inoculum (bacterial and yeast suspension) was prepared from a 24-h culture on NB for bacterial suspension and on TSB for yeast suspension. Extraction and isolation using various method of chromatography. Isolated compounds were characterized by spectroscopic means. Our study showed antimicrobial activity from crude ethanol extract of leaves P. betle L. var. nigra against two oral pathogenic bacteria and opportunistic pathogenic yeast with concentration 0.5% and 1%. The first report of two new amides derivatives, piperenamide A (1) and piperenamide B (2) in P. betle L. var. nigra.

Mammalian-like type II glutaminyl cyclases in Porphyromonas gingivalis and other oral pathogenic bacteria as targets for treatment of periodontitis.

The development of a targeted therapy would significantly improve the treatment of periodontitis and its associated diseases including Alzheimer Disease, rheumatoid arthritis, and cardiovascular diseases. Glutaminyl cyclases (QCs) from the oral pathogens Porphyromonas gingivalis, Tannerella forsythia and Prevotella intermedia represent attractive target enzymes for small-molecule inhibitor development, as their action is likely to stabilize essential periplasmic and outer membrane proteins by N-terminal pyroglutamination. In contrast to other microbial QCs that utilize so-called type I enzymes, these oral pathogens possess sequences corresponding to type II QCs, observed hitherto only in animals. However, whether differences between these bacteroidal QCs and animal QCs are sufficient to enable development of selective inhibitors is not clear. To learn more, we recombinantly expressed all three QCs. They exhibit comparable catalytic efficiencies and are inhibited by metal chelators. Crystal structures of the enzymes from P. gingivalis (PgQC) and T. forsythia (TfQC) reveal a tertiary structure composed of an eight-stranded β-sheet surrounded by seven α-helices, typical of animal type II QCs. In each case, an active site Zn ion is tetrahedrally coordinated by conserved residues. Nevertheless, significant differences to mammalian enzymes are found around the active site of the bacteroidal enzymes. Application of a PgQC-selective inhibitor described here for the first time results in growth inhibition of two P. gingivalis clinical isolates in a dose dependent manner. The insights gained by these studies will assist in the development of highly specific small-molecule bacteroidal QC inhibitors, paving the way for alternative therapies against periodontitis and associated diseases.

Effect of Degree of Conversion of Different Resin Composite Monomers (Methacrylate and Silorane) on Two Caries-Associated Bacteria

Abstract Background and Objectives: The biological response of oral bacteria to dental restorative polymer composites is mediated by the release of unpolymerized residual monomers. The aims of the present study were first, evaluating the effect of composite elutes from methacrylate composite resins and silorane-based composites on two cariogenic bacterial pathogens: Streptococcus mutans and Lactobacillus acidophilus and second, determination of degree of conversion (DC) of standardized discs made from the low-shrinkage silorane-based composite (FiltekTM P90) resin and methacrylate-based composite resin (FiltekTM Z350XT nanocomposite, FiltekTM Z350 Flow) using Fourier transform infrared spectroscopy (FTIR). Materials and Methods: Thirty-six composite specimens were prepared for the agar diffusion test and dissolved in a solvent (dimethyl sulfoxide) to attain a suspension, which was used to assess the effect of the residual monomers from methacrylate composite resins and silorane-based composites on the growth of S. mutans and L. acidophilus. To avoid more dilutions of the specimens, the colonies of bacteria were counted by the naked eye. Thirty composite specimens of 2 mm × 6 mm were polymerized for DC test, and the DC was measured using FTIR, also for unpolymerized composite resin. Results: The growth of S. mutans bacteria was inhibited when cultured with Filtek Z350 Flow composite resin, while the growth of L. acidophilus bacteria was stimulated by the Filtek Silorane p90 and Filtek Z350 Flow composite resin. The DC test with the Filtek Silorane composite resin showed highest DC (58%), then the Filtek Z350XT (Nanocomposite) (42%) followed by the Filtek Z350 Flow (Flowable) showed lowest (35%). Conclusions: Our results demonstrate that composite filling materials have a versatile nature of effect on oral pathogenic bacteria, which could modulate their pathogenesis. Dentists may thus select the appropriate type of composite filling according to the caries susceptibility of patients.

Mammalian-like type II glutaminyl cyclases in Porphyromonas gingivalis and other oral pathogenic bacteria as targets for treatment of periodontitis

The development of a targeted therapy would significantly improve the treatment of periodontitis and its associated diseases including Alzheimer’s disease, rheumatoid arthritis, and cardiovascular diseases. Glutaminyl cyclases (QCs) from the oral pathogens Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia represent attractive target enzymes for small-molecule inhibitor development, as their action is likely to stabilize essential periplasmic and outer membrane proteins by N-terminal pyroglutamination. In contrast to other microbial QCs that utilize the so-called type I enzymes, these oral pathogens possess sequences corresponding to type II QCs, observed hitherto only in animals. However, whether differences between these bacteroidal QCs and animal QCs are sufficient to enable development of selective inhibitors is not clear. To learn more, we recombinantly expressed all three QCs. They exhibit comparable catalytic efficiencies and are inhibited by metal chelators. Crystal structures of the enzymes from P. gingivalis (PgQC) and T. forsythia (TfQC) reveal a tertiary structure composed of an eight-stranded β-sheet surrounded by seven α-helices, typical of animal type II QCs. In each case, an active site Zn ion is tetrahedrally coordinated by conserved residues. Nevertheless, significant differences to mammalian enzymes are found around the active site of the bacteroidal enzymes. Application of a PgQC-selective inhibitor described here for the first time results in growth inhibition of two P. gingivalis clinical isolates in a dose-dependent manner. The insights gained by these studies will assist in the development of highly specific small-molecule bacteroidal QC inhibitors, paving the way for alternative therapies against periodontitis and associated diseases.

Isolation and Functional Characterization of Fusobacterium nucleatum Bacteriophage.

Bacteriophages are viruses that specifically lyse bacteria. They have demonstrated potential in applications as antibacterial agents in medicine, agriculture, and environmental remediation. Due to the complex and dynamic nature of the oral microbiome, antibiotic treatment of chronic, polymicrobial oral diseases may lead to dysbiosis. In these diseases, bacteriophages may provide targeted activity against oral bacteria without such disruption to the broader microbial community. In this chapter, we describe the methods for screening samples that may contain bacteriophages against oral pathogenic bacteria, and using the example of FNU1, the bacteriophage we isolated against Fusobacterium nucleatum, describe the process of bacteriophage purification and characterization.

Stability and Antibacterial Property of Polyherbal Mouthwash Formulated Using Local Ingredients

The oral cavity is a home to more than 500 bacterial species. Although some of the oral bacteria are harmless, there are certain species that may cause oral plaques, bad breath , and mouth disease. Thus, maintaining a good oral hygiene is essential for a healthy mouth and body. The present study aimed to formulate a polyherbal mouthwash that may have antibacterial properties. Mouthwash formulations were prepared containing varying percentages of herbal extracts, with each formulation stored at 12 °C and 25 °C. Over the course of 12 weeks, the appearance and pH of the formulated mouthwash were measured. The mouthwash formulations maintained good homogeneity and color when stored at 25 °C, displaying lower pH level ranging between 3.71 and 4.85. Although the mouthwash stored at 12 °C maintained good homogeneity, a change in color in the formulation was evident and a more unstable pH readings were recorded. Antibacterial assay showed that mouthwash formulations stored at 25 °C had better inhibitory activity compared to those stored at 12 °C. Furthermore, mouthwash formulation containing (30% v/v) aleppo oak extract as the major ingredient conferred the greatest inhibition zone diameter (IZD = 10-18 mm) against salivary bacteria compared to formulations with (30% v/v) clove and (30% v/v) turmeric extracts as major ingredients. The best polyherbal mouthwash formulation in terms of inhibiting bacterial growth followed the 3:1:2 ratio for aleppo oak extract, clove extract, and turmeric, respectively. Therefore, the polyherbal mouthwash formulated in this study has the potential to be optimized and commercialized to antagonize growth of pathogenic oral bacteria.

Extraction and characterization of lectin from Cicerarietinum black and Prunusdulcis nut raw, its anti-inflammatory, antibacterial activity against oral pathogens

Lectins are proteins essential for the biological recognition of cells a key factor for killing microbes. Since, legumes are good source, we extracted lectin from Cicerarietinum Black (CiarBL), Prunusdulcis nut raw (PruDuNRL), characterized for its key properties. The protein content of CiarBL was 13.13 ± 4.53, 25.45 ± 3.93, specific activity was 472.97, 243.80HAU/mg protein and for Prunusdulcis nut raw it was 04.60 ± 1.60, 17.84 ± 1.41and specific activity was 365.71, 252.52 HAU/mg protein. The total hemeagglutination activity of both lectin was found to be 512HAU. Blood group specificity analysis showed specificity to O+ and B+ for CiarBL, and for PruDuNRL O+, A+, B+ human erythrocytes both the lectin was specific to goat blood among the animal blood tested. The hemeagglutination inhibition assay showed specificity to glucose, maltose alone for CiarBL. While, PruDuNRL was glucose, sucrose, maltose, xylose specific. Both exhibited good antioxidant activity but erythrocyte membrane stability was higher with CiarBL when compared to PruDuNRL. CiarBL demonstrated promising stability to urea. While, PruDuNRL depicted sensitivity to pH, temperature, urea but both showed stability to salts such as FeCl3, Na2So4, CaCl2. SDS PAGE, authenticate it as low molecular weight i.e. 20, 29 KDa for CiarBL, for PruDuNRL 20 to 60KDa, 115KDa, the molecular weight was ranging from low to high. The antibacterial effect against gram positive oral pathogenic bacteria showed good result for CiarBL against Streptococcus oralis, Streptococcus pyogens at all concentration studied, moderate activity with Propionibacterium acnes, Staphylococcus aureus at 100 µg/ml. For PruDuNRL, the antibacterial activity was found to be decreased in the order of Streptococcus pyogenes < Streptococcus oralis < Propionibacterium acnes < Staphylococcus aureus. The possible mechanism involved was lectin interaction with teichoic and teichuronic acids, peptidoglycans, lipopolysaccharides on the surface of the bacteria. Lectin possessing good antioxidant, anti-inflammatory activity could hold better pharmacological applications. So, the result obtained from the present study paves way for further research in various avenues of clinical microbiology.

Synergistic Effect of Methanolic Extracts of Rosmarinus Officinalis and Eugenia caryophyllata on Biofilm of Oral Pathogenic Bacteria

Synergistic Effect of Methanolic Extracts of Rosmarinus Officinalis and Eugenia caryophyllata on Biofilm of Oral Pathogenic Bacteria

Rhamnolipids and surfactin inhibit the growth or formation of oral bacterial biofilm

BackgroundBacteria survive in various environments by forming biofilms. Bacterial biofilms often cause significant problems to medical instruments and industrial processes. Techniques to inhibit biofilm formation are essential and have wide applications. In this study, we evaluated the ability of two types of biosurfactants (rhamnolipids and surfactin) to inhibit growth and biofilm formation ability of oral pathogenic bacteria such as Aggregatibacter actinomycetemcomitans, Streptococcus mutans, and Streptococcus sanguinis.ResultsRhamnolipids inhibited the growth and biofilm formation ability of all examined oral bacteria. Surfactin showed effective inhibition against S. sanguinis ATCC10556, but lower effects toward A. actinomycetemcomitans Y4 and S. mutans UA159. To corroborate these results, biofilms were observed by scanning electron microscopy (SEM) and confocal microscopy. The observations were largely in concordance with the biofilm assay results. We also attempted to determine the step in the biofilm formation process that was inhibited by biosurfactants. The results clearly demonstrated that rhamnolipids inhibit biofilm formation after the initiation process, however, they do not affect attachment or maturation.ConclusionsRhamnolipids inhibit oral bacterial growth and biofilm formation by A. actinomycetemcomitans Y4, and may serve as novel oral drug against localized invasive periodontitis.

Oral commensal bacteria differentially modulate epithelial cell death

ObjectiveEpithelial cell death is an important innate mechanism at mucosal surfaces, which enables the elimination of pathogens and modulates immunoinflammatory responses. Based on the antimicrobial and anti-inflammatory properties of cell death, we hypothesized that oral epithelial cell (OECs) death is differentially modulated by oral bacteria. Material and MethodsWe evaluated the effect of oral commensals Streptococcus gordonii (Sg), Streptococcus sanguinis (Ss), and Veillonella parvula (Vp), and pathogens Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), and Fusobacterium nucleatum (Fn) on OEC death. Apoptosis and necrosis were evaluated by flow cytometry using FITC Annexin-V and Propidium Iodide staining. Caspase-3/7 and caspase-1 activities were determined as markers of apoptosis and pyroptosis, respectively. IL-1β and IL-8 protein levels were determined in supernatants by ELISA. ResultsSignificant increases in apoptosis and necrosis were induced by Sg and Ss. Pg also induced apoptosis, although at a substantially lower level than the commensals. Vp, Tf, and Fn showed negligible effects on cell viability. These results were consistent with Sg, Ss, and Pg activating caspase-3/7. Only Ss significantly increased the levels of activated caspase-1, which correlated to IL-1β over-expression. ConclusionsOEC death processes were differentially induced by oral commensal and pathogenic bacteria, with Sg and Ss being more pro-apoptotic and pro-pyroptotic than pathogenic bacteria. Oral commensal-induced cell death may be a physiological mechanism to manage the extent of bacterial colonization of the outer layers of mucosal epithelial surfaces. Dysbiosis-related reduction or elimination of pro-apoptotic oral bacterial species could contribute to the risk for persistent inflammation and tissue destruction.

Is Implant Placement in the Operating Room a Risk Factor for the Development of Peri-Implantitis? A Retrospective Cohort Analysis

This study aims to identify if preoperative antibiotic administration is a protective factor for the development of peri-implantitis in implants placed in the operating room vs outpatient clinic. A retrospective cohort study was conducted at the Philadelphia Veterans Affairs Medical Center from 2006 to 2013. Physician encounter notes within 3 months of implant placement were used to gather data about patients’ health status, including the setting of implant placement in the operating room vs outpatient clinic. Operative report notes were used to assess administration of antibiotic prophylaxis, recorded as none, oral, or intravenous administrations. Implant status was assessed using dental encounter notes and radiographs from follow-up appointments at 1, 3, 5, and 10 years. Peri-implantitis was defined as radiographic evidence of changes in the crestal bone level, clinical evidence of bleeding on probing, with or without suppuration.1 Electronic medical records of 942 implants placed in 398 unique patients were retrospectively analyzed. Descriptive statistics were computed using the SAS System (SAS Institute Version 9.4, 2002-2012, Cary, NC). Predictor variables were implant placement in the operating room or outpatient clinic and administration of preoperative antibiotics. The primary outcome variable was the presence of peri-implantitis. Descriptive, bivariate, and multiple logistic regression analyses were performed to measure the association between predictive variables and development of peri-implantitis. Of the 942 implants placed, 205 (22%) developed peri-implantitis. Overall, placement of implants in an operating room was shown to be associated with an increased risk in the presence of peri-implantitis (P ≤ .0001) when compared to implants placed in the outpatient clinic. When controlling for preoperative antibiotics, patients who received implants in the operating room were still found to be at risk for developing peri-implantitis (P = .0015). The data from this study show that implants placed in the operating room were 4 times more likely to develop peri-implantitis compared to implants placed in the outpatient clinic (OR = 4.056, 95% Cl 2.697-6.102). To our knowledge, no existing literature demonstrates this significant relationship. Our data show that preoperative antibiotics are protective against the development of peri-implantitis in patients who receive implants in the operating room. When controlling for preoperative antibiotics, operating room patients’ risk of developing peri-implantitis decreased by nearly 35% (OR = 2.633, 95% Cl 1.448-4.788). Studies have demonstrated that in a peri-implantitis model, antibiotic-treated specimens attenuated natural bone loss. The authors suggest that preoperative antibiotic administration may decrease the occurrence of peri-implantitis by reversing inflammatory responses and decreasing attachment loss via attenuation of pathogenic oral bacteria at the site of implant placement.2 Therefore, the administration of preoperative antibiotics, especially in medically complex patients who cannot tolerate implant placement in an outpatient clinic, may temper the progression of pathological processes around the peri-implant tissues. Analysis of implants placed at the Philadelphia VA Medical Center revealed an important association between the setting of implant placement, use of preoperative antibiotics, and the development of peri-implantitis. Our study shows that a standardized preoperative antibiotic regimen can play an important role in decreasing the development of peri-implantitis in patients who receive implants in an operating room. Administration of preoperative antibiotics in these patients may provide an opportunity to abate inflammatory reactions as a result of an existing complex disease and provide protection against the development of peri-implantitis. In addition to completing prospective studies, identification of other protective factors in this high-risk patient population is a necessity.

Antimicrobial Activity of EPA and DHA against Oral Pathogenic Bacteria Using an In Vitro Multi-Species Subgingival Biofilm Model.

In search for natural products with antimicrobial properties for use in the prevention and treatment of periodontitis, the purpose of this investigation was to evaluate the antimicrobial activity of two omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), using an in vitro multi-species subgingival biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of EPA and DHA extracts (100 µM) and the respective controls were assessed on 72 h biofilms by their submersion onto discs for 60 s. Antimicrobial activity was evaluated by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). ANOVA with Bonferroni correction was used to evaluate the antimicrobial activity of each of the fatty acids. Both DHA and EPA significantly reduced (p < 0.001 in all cases) the bacterial strains used in this biofilm model. The results with CLSM were consistent with those reported with qPCR. Structural damage was evidenced by SEM in some of the observed bacteria. It was concluded that both DHA and EPA have significant antimicrobial activity against the six bacterial species included in this biofilm model.