Antimicrobial effect of phytic acid on Enterococcus faecalis

Objective One of the properties of an ideal root canal irrigant is the ability to eradicate Enterococcus faecalis which is one of the most resistant microorganisms encountered in persistent peri-radicular lesions. The aim of this study was to test the in vitro antibacterial effectiveness of a naturally occurring agent called phytic acid (IP6) against E. faecalis and compare it to the antibacterial activities of clinically used irrigants: sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), phosphoric acid (PA) and chlorhexidine (CHX). Design The antimicrobial activities of 5% IP6, 5% NaOCl, 18% EDTA, 37% PA and 2% CHX against E. faecalis were determined using disk diffusion test. Minimum inhibitory concentration (MIC) was calculated by broth macrodilution method. The minimal bactericidal concentration (MBC) was determined for the used agents by culturing the clear broth of MIC tests. Results The results of agar diffusion test showed statistically signiï¬cant differences between the groups. PA showed a larger zone when compared to other tested materials (p< 0.05). There was no statistical significant difference between NaOCl, EDTA and CHX (p=0.098). IP6 showed the smallest zone of inhibition when compared to all groups (p< 0.05).The recorded MIC and MBC values for IP6 were 0.156% and 0.625%; respectively. The MIC and MBC values for PA were 0.578% and 4.6% and for NaOCl 0.093% and 0.375%, respectively. EDTA MIC value was 0.14 % but it showed no bactericidal activity. CHX was excluded from MIC test as immediate precipitation and turbidity occurred after mixing CHX with Mueller Hinton Broth. Conclusions Within the limitation of this study and despite that IP6 showed the smallest zone of inhibition in agar diffusion test, the results of MIC and MBC indicated that IP6 exhibits in vitro antibacterial effect against E. faecalis at low concentrations

Phytic acid demonstrates rapid antibiofilm activity and inhibits biofilm formation when used as a surface conditioning agent

Root canal infections are associated with biofilms and are treated with chemical irrigants with a high success rate. However, treatment failure does arise, which is attributed primarily to resistance exhibited by biofilms. Currently used irrigants in root canal treatment have disadvantages, and there is therefore a need for more biocompatible alternatives with antibiofilm properties to reduce root canal treatment failure and complications. The aim of this study was to evaluate the in vitro antibiofilm properties of phytic acid (IP6), which is a potential alternative treatment agent. Single- and dual-species biofilms of Enterococcus faecalis and Candida albicans were developed on the well surfaces of 12-well plates and on hydroxyapatite (HA) coupons, and then exposed to IP6. In addition, selected HA coupons were preconditioned with IP6 before biofilm development. IP6 demonstrated bactericidal effects and altered the metabolic activity of biofilm cells. Confocal laser-scanning microscopy showed that IP6 caused significant and rapid reduction in live biofilm cells. At sublethal concentrations, IP6 did not alter the expression of tested virulence genes except for C. albicans hwp1, the expression of which was upregulated but not reflected by a change in hyphal transformation. IP6-preconditioned HA coupons led to extensive inhibition of dual-species biofilm formation. The results of this study highlight for the first time the antibiofilm inhibitory properties of IP6 and the potential for its exploitation in several clinical applications

The effect of reduced glutathione on the toxicity of silver diamine fluoride in rat pulpal cells

Introduction: Due to its ability to arrest untreated dental caries, silver diamine fluoride (SDF) has been advocated for indirect pulp capping procedures. However, the high concentrations of silver and fluoride in SDF raise concerns about its biocompatibility to pulpal tissues. Objectives: This study aimed to investigate the effect of SDF on the viability, alkaline phosphatase (ALP) activity, and morphology of pulpal-like cells (RPC-C2A) and to evaluate the influence of reduced glutathione (GSH) on SDF-induced cytotoxicity and deposit formation on dentin. Methodology: The cytotoxicity of diluted 38% SDF solutions (10-4 and 10-5), with or without the addition of 5 mM or 50 mM GSH, was evaluated at 6 and 24 hours. Cell viability was detected using WST-8 and the effect on ALP activity was performed using an ALP assay kit. Cell morphology was observed using a phase-contrast microscope. Scanning electron microscopy analysis was conducted to evaluate the effect of GSH incorporation or conditioning on SDF-induced deposit formation on dentin discs. Cytotoxicity data were analyzed by two-way analysis of variance (ANOVA) and Tukey post hoc tests (p<0.05). Results: There were significant differences between the groups. The results demonstrated that all tested SDF dilutions caused a remarkable cytotoxic effect, while the addition of GSH prevented SDF-induced damage at 6-hour exposure time in the higher dilution of SDF. Dentin treated with plain SDF or GSH-incorporated SDF solution showed deposit formation with occluded dentinal tubules, unlike the other groups. Conclusion: SDF severely disturbed the viability, mineralization-ability, and morphology of pulpal-like cells, while controlled concentrations of GSH had a short-term protective effect against SDF-induced damage. GSH showed an inhibitory effect on SDF-induced dentinal deposit formation. Further research is warranted to evaluate the effect of GSH on caries-arresting, anti-hypersensitivity, and antibacterial functions of SDF

Microbial metabolic genes crucial for S. aureus biofilms: an insight from re-analysis of publicly available microarray datasets

Bacterial biofilms are microbial lifestyles found in all environments. Up to 80% of human infections and 60-70% of hospital-acquired infections have a biofilm origin, with Staphylococcus aureus one of the leading causes of these infections. Microorganisms in biofilms exhibit significant antimicrobial resistance which poses important treatment challenges, hence the urgent need to identify novel antibiofilm strategies. Microbes form biofilms in response to various factors, and once these 3-dimentional structures form they are highly recalcitrant to removal. The switch from planktonic lifestyle to the biofilm protected mode of growth results in a phenotypic shift in the behavior of the microorganisms in terms of growth rate and gene expression. Given these changes, investigation of microbial gene expression and their modulation at different stages of biofilm maturation is needed to provide vital insight into the behaviour of biofilm cells. In this study, we analysed publicly available transcriptomic dataset of S. aureus biofilm at different stages of maturation to identify consistently upregulated genes irrespective of the biofilm maturation stage. Our reanalysis identified a total of 6 differentially expressed genes upregulated in both 48 and 144-h old S. aureus biofilms. Functional analysis revealed that these genes encode for proteins which play a role in key microbial metabolic pathways. However, these genes, as yet, are unrelated or poorly studied in the context of biofilm. Moreover, the findings of this in silico work, suggest that these genes may represent potential novel targets for the development of more effective antibiofilm strategies against S. aureus biofilm-associated infections

Antimicrobial activity of phytic acid: an emerging agent in dentistry

Background: Phytic acid (IP6) is a promising and emerging agent, and because of its unique structure and distinctive properties, it lends itself to several applications in dentistry. Recently, IP6 was proposed as a potential chelating agent in endodontics. However, there is limited knowledge regarding its antimicrobial and antibiofilm effectiveness. The aims of this study, were therefore to evaluate the antimicrobial and antibiofilm activities of IP6 against a range of microbial species and compare these with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl). The contact time required for IP6 to exert its bactericidal effect on Enterococcus faecalis was also determined. Methods: The inhibitory and biocidal activities of IP6, EDTA and NaOCl were assessed using a broth microdilution assay against 11 clinical and reference strains of bacteria and a reference strain of Candida albicans. The contact time required for various IP6 concentrations to eliminate planktonic cultures of E. faecalis was determined using a membrane filtration method according to BS-EN-1040:2005. IP6 bactericidal activity was also evaluated using fluorescent microscopy, and the antibiofilm activity of the test agents was also determined. Results: IP6 was biocidal against all tested microorganisms. At concentrations of 0.5%, 1% and 2%, IP6 required 5 min to exert a bactericidal effect on E. faecalis, while 5% IP6 was bactericidal after 30 s. IP6 also eradicated biofilms of the tested microorganisms. In conclusion, IP6 had notable antimicrobial effects on planktonic and biofilm cultures and exhibited rapid bactericidal effects on E. faecalis. This research highlighted, for the first time the antimicrobial and antibiofilm properties of IP6, which could be exploited, not only in dental applications, but also other fields where novel strategies to counter antimicrobial resistance are required

Phytic acid: properties and potential applications in dentistry

Inositol hexaphosphate (IP6) is the most abundant inositol phosphate in nature and an essential molecule for different biological functions. IP6 has a unique structure granting it distinctive properties; the high negative charge density provides IP6 with an immense chelating ability and valuable antioxidant properties. IP6 is also simple and cost-effective to produce. These features have attracted researchers and entrepreneurs to further study IP6 for a wide variety of applications in areas such as pharmaceutical, food and chemical industries, medicine, pharmacy, nutrition, and dentistry. The interest in IP6 in the dental field unfolded many decades ago following identification of a cariostatic ability and a positive impact on reducing enamel dissolution. Subsequently, IP6’s anti-plaque, anti-calculus and cement-forming properties have been investigated. Despite encouraging findings, there was a phase of decreased attention to IP6 which slowed down research progress. However, the potential use of IP6 has recently been revisited through several publications that provided deeper understanding to its mechanisms of action in the aforementioned applications. Studies have also explored new applications in endodontics, adhesive, preventive and regenerative dentistry, and IP6’s role in improving the characteristics and performance of dental materials. Evidence of the merits of IP6 in dentistry is now substantial, and this narrative review presents and discusses the different applications proposed in the literature and gives insight of future use of IP6 in the fields of orthodontics, implant and pediatric dentistry

The effect of phytic acid on enzymatic degradation of dentin

We evaluated the effect of phytic acid on matrix metalloproteinase (MMP)- or cysteine cathepsin (CC)-mediated dentin degradation. Demineralized dentin beams were divided into five groups (n = 12) and treated with 1%, 2%, or 3% phytic acid or with 37% phosphoric acid. Untreated demineralized beams served as controls. After incubation for 1 or 3 wk, dry mass loss was determined and aliquots of incubation media were analysed for cross-linked telopeptide of type I collagen (ICTP) fragments for MMP-mediated and c-terminal telopeptide of type I collagen (CTX) for cathepsin-k-mediated degradation. The direct effect of phytic acid was evaluated using MMP activity assay. Data were analysed using repeated-measures anova. ICTP releases with 1% and 2% phytic acid treatment were statistically significantly lower than those following phosphoric acid treatment at 3 wk. The CTX release for phytic acid-treated beams at 3 wk was not significantly different from that of untreated control beams, but it was significantly lower than that of phosphoric acid-treated beams. Their MMP activities at 3 wk were not significantly different from those of the controls but they were significantly lower than those seen for phosphoric acid-treated beams. Compared to phosphoric acid, phytic acid treatment resulted in a reduced dentinal host-derived endogenous enzymatic activity and collagen degradation

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Erosive Potential of Various Beverages in the United Arab Emirates: pH Assessment

Objectives: The United Arab Emirates (UAE) is one of the top 5 countries in the world in terms of juice consumption per capita. The rising consumption of beverages is a major contributor to a plethora of diseases, including heightened risks of developing obesity, diabetes, and osteoporosis. Beverages with low pH also tend to magnify the risk of long-term dental erosion. This paper evaluated the pH of various beverages in the UAE to help determine their erosive potential. Materials and Methods: 306 beverages were collected from different stores in the UAE. Drinks were categorized into 8 categories: carbonated drinks, energy drinks, sparkling water, iced teas, juices, malt beverages, coconut water, and sports drinks. Three readings were taken for each drink using a pH meter at room temperature. Results: 88% of all beverages had a pH of less than 4.0, and the remaining 12% had a pH of 4.0 or more. 37% of the beverages tested were extremely erosive (pH &lt; 3.0), 51% were erosive (pH 3.0–3.99), and 12% were mildly erosive (pH ≥ 4.0). Bickford’s Classic Cola and Tesco Lemon Juice were the most acidic beverages (pH &lt; 2.4). The most identified acids in the tested beverages were citric, phosphoric, ascorbic, and malic acids. Conclusions: The majority of beverages in the UAE are erosive to dentition as the pH is below 4. Future studies to raise public awareness on the effect of acidic drinks on tooth structure are needed