Novel Approaches to the Control of Oral Microbial Biofilms

Exploring the Efficacy of Novel Therapeutic Strategies for Periodontitis: A Literature Review

Periodontitis, a prevalent oral condition, is facing difficulties in therapeutic approaches, sometimes leading to failure. This literature review was conducted to investigate the diversity of other therapeutic approaches and their potential contributions to the successful management of the disease. This research scrutinized the alterations in microbial diversity and imbalances in crucial microbial species, which contribute significantly to the pathogenesis of periodontitis. Within the limitations of this study, we highlight the importance of understanding the treatment plan's role in periodontitis disease, opening the way for further research and innovative treatment plans to mitigate the impact of periodontitis on oral health. This will aid both healthcare professionals and patients in preventing and effectively treating periodontitis, ultimately improving oral health outcomes and overall systemic health and well-being.

Inhibition of pathogenic microbes in oral infectious diseases by natural products: Sources, mechanisms, and challenges

The maintenance of oral health is of utmost importance for an individual's holistic well-being and standard of living. Within the oral cavity, symbiotic microorganisms actively safeguard themselves against potential foreign diseases by upholding a multifaceted equilibrium. Nevertheless, the occurrence of an imbalance can give rise to a range of oral infectious ailments, such as dental caries, periodontitis, and oral candidiasis. Presently, clinical interventions encompass the physical elimination of pathogens and the administration of antibiotics to regulate bacterial and fungal infections. Given the limitations of various antimicrobial drugs frequently employed in dental practice, the rising incidence of oral inflammation, and the escalating bacterial resistance to antibiotics, it is imperative to explore alternative remedies that are dependable, efficacious, and affordable for the prevention and management of oral infectious ailments. There is an increasing interest in the creation of novel antimicrobial agents derived from natural sources, which possess attributes such as safety, cost-effectiveness, and minimal adverse effects. This review provides a comprehensive overview of the impact of natural products on the development and progression of oral infectious diseases. Specifically, these products exert their influences by mitigating dental biofilm formation, impeding the proliferation of oral pathogens, and hindering bacterial adhesion to tooth surfaces. The review also encompasses an examination of the various classes of natural products, their antimicrobial mechanisms, and their potential therapeutic applications and limitations in the context of oral infections. The insights garnered from this review can support the promising application of natural products as viable therapeutic options for managing oral infectious diseases.

Dental aerosol-producing treatments: Comparison of contamination patterns of face shields and surgical masks

During the COVID-19 pandemic, dental face shields were recommended to protect the eyes. This study aimed to examine to what extent face shield and mask contamination differ when a pre-procedural mouth rinsing with Chlorhexidine (CHX) is conducted before treatment. In this prospective, randomized study, three groups of subjects were formed (rinsing with 0.1% CHX, water, or no rinsing (control) before aerosol-producing treatments). After each of the 301 treatments, the practitioner's face shield was swabbed with eSwab and the mask was brought into contact with agar plates. Sampling was done from the exterior surface only. Samples were cultured for 48 h at 35 °C under aerobic and anaerobic conditions. Bacteria were classified by phenotypic characteristics, biochemical test methods, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Colony-forming units were counted and mean values were compared (WSR, H-test, U-test, p < 0.05). Within each subject group, face shields showed significantly more contamination than surgical masks (control group: 350 CFU, 50 CFU; intervention water: 270 CFU, 40 CFU; intervention CHX: 250 CFU, 30 CFU). Comparison of face shields of the different subject groups did not reveal any statistically significant differences. However, CHX resulted in a statistically significant bacterial reduction on surgical masks compared to the water and control group (control: 50 CFU, intervention water: 40 CFU, intervention CHX: 30 CFU). Contamination of face shields and surgical masks was highest in the control group, followed by the water group, and lowest in the intervention group with CHX. Streptococcus spp. and Staphylococcus spp. dominated, representing the oral and cutaneous flora. Contamination of masks worn with or without face shields did not differ. Presumably, face shields intercept first splashes and droplets, while the masks were mainly exposed to bioaerosol mist. Consequently, face shields protect the facial region and surroundings from splashes and droplets, but not the mask itself. A pre-procedural mouth rinse with CHX had no statistically significant reducing effect on contamination of the face shield, but a statistically significant reducing effect was observed on contamination of the mask.

Extracellular Interaction of Bacillus thuringiensis, ATP and Phage 0105phi7-2: A Potential New Anti-Bacterial Strategy

The following hypothesis proposes non-diffusive, environmental bacteriophage (phage) motion. (1) Some phage-hosting, motile bacteria undergo chemotaxis down ATP concentration gradients to escape lysis-inducing conditions, such as phage infection. (2) Some phages respond by non-infective binding to the motile bacteria. (3) When the bacteria reach a lower ATP concentration, which is a condition that signals increased density of phage-susceptible bacteria, the phage converts, Trojan-horse-like, to productive binding and infection. This hypothesis was previously proposed for Bacillus thuringiensis siphophage 0105phi7-2. It is tested here and confirmed with the following observations. (1) B. thuringiensis is found, macroscopically, preferentially located at low ATP concentrations when propagated in-gel after inoculation in the center of an artificially generated ATP concentration gradient. (2) Inoculating phage 0105phi7-2 at the bacteria inoculation site, 2-3 h after inoculation of bacteria, results in cell lysing activity that moves with the bacteria, without a visible trail of lysis. Trojan-horse-like behavior is consistent with only biofilm-inhabiting phages because environmental selection for this behavior requires limited fluid flows. We propose using artificial ATP concentration gradients to instigate Trojan-horse-like phage behavior during phage therapy of bacterial biofilms.

Phytochemical profile and antimicrobial activity of essential oils from two Syzygium species against selected oral pathogens

BACKGROUND

The genus Syzygium (Myrtaceae) comprises several essential oil-rich species that are utilized traditionally for treating tooth infections and toothache. The current study aimed to extract essential oils (EOs) from the leaves of Syzygium samarangense and Syzygium malaccense cultivated in Egypt for the first time and screen their antimicrobial potential against oral-related pathogens.

METHODS

The intended EOs were extracted using hydrodistillation (HD) by boiling fresh leaves with distilled water; supercritical fluid (SF) by extracting the dried leaves using supercritical CO2 at 40 °C and 150 bar; and the headspace (HS) in which the fresh leaves were heated in a glass vial and the vaporized aroma were analyzed. The volatile constituents were analyzed using GC/MS and identified by comparing the experimental Kovats' retention indices with the literature. The antimicrobial activity was assessed against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Candida albicans using agar diffusion, microwell dilution, and biofilm formation assays. Statistical significance (p < 0.05) was determined by applying one-way ANOVA and Duncan's post hoc test.

RESULTS

The yield of the extracted EOs differs between the applied methods, and the SF approach harvested the maximum (0.52-0.46%). The GC-MS analysis of SF EOs revealed a discrepancy between the two species. Since S. malaccense showed an abundance of hydrocarbons represented mainly by squalene (60.60%), S. samarangense was deemed to have oxygenated sesquiterpenes exemplified in globulol (52.09%). On the other side, the HD and HS EOs were sequentially comparable, while differed in the percentage of their majors. γ-terpinene (33.06%) pioneered the HS-derived aroma of S. malaccense, while S. samarangense was abundant with α-pinene (30.18%). Concurrently, the HD EOs of S. malaccense and S. samarangense were commonly denoted by caryophyllene oxide (8.19%-18.48%), p-cymene (16.02%- 19.50%), and γ-terpinene (12.20%-17.84). Ultimately, both species EOs exhibited broad-spectrum antimicrobial potential, although the HD EO was more potent than the SF EO. The HD EOs of both species potently inhibited the growth of E. coli (MIC 3.75 µL/mL) and suppressed C. albicans biofilm formation by 83.43 and 87.27%, respectively. The SF-EOs efficiently suppressed the biofilm formation of Gram-positive bacteria by 76.45%-82.95%.

CONCLUSION

EOs extracted from both species by different methods possessed a unique blend of volatile components with broad-spectrum antimicrobial activity. They were promoted as bioactive hits for controlling oral infections, however further investigations concerning their safety in clinical settings are needed.

The effect of photodynamic therapy in controlling the oral biofilm: A comprehensive overview

Several resistance mechanisms are involved in dental caries, including oral biofilms. An accumulation of bacteria on the surface of teeth is called plaque. Periodontitis and gingivitis are caused by dental plaque. In this review article, we aimed to review the studies associated with the application of photodynamic therapy (PDT) to prevent and treat various microbial biofilm-caused oral diseases in recent decades. There are several studies published in PubMed that have described antimicrobial photodynamic therapy (APDT) effects on microorganisms. Several in vitro and in vivo studies have demonstrated the potential of APDT for treating endodontic, periodontal, and mucosal infections caused by bacteria as biofilms. Reactive oxygen species (ROS) are activated in the presence of oxygen by integrating a nontoxic photosensitizer (PS) with appropriate wavelength visible light. By causing irreversible damage to microorganisms, ROS induces some biological and photochemical events. Testing several wavelengths has been conducted to identify potential PS for APDT. A standard protocol is not yet available, and the current review summarizes findings from dental studies on APDT.

Novel Bioactive Nanocomposites Containing Calcium Fluoride and Calcium Phosphate with Antibacterial and Low-Shrinkage-Stress Capabilities to Inhibit Dental Caries

OBJECTIVES

Composites are commonly used for tooth restorations, but recurrent caries often lead to restoration failures due to polymerization shrinkage-stress-induced marginal leakage. The aims of this research were to: (1) develop novel low-shrinkage-stress (L.S.S.) nanocomposites containing dimethylaminododecyl methacrylate (DMADDM) with nanoparticles of calcium fluoride (nCaF2) or amorphous calcium phosphate (NACP) for remineralization; (2) investigate antibacterial and cytocompatibility properties.

METHODS

Nanocomposites were made by mixing triethylene glycol divinylbenzyl ether with urethane dimethacrylate containing 3% DMADDM, 20% nCaF2, and 20% NACP. Flexural strength, elastic modulus, antibacterial properties against Streptococcus mutans biofilms, and cytotoxicity against human gingival fibroblasts and dental pulp stem cells were tested.

RESULTS

Nanocomposites with DMADDM and nCaF2 or NACP had flexural strengths matching commercial composite control without bioactivity. The new nanocomposite provided potent antibacterial properties, reducing biofilm CFU by 6 logs, and reducing lactic acid synthesis and metabolic function of biofilms by 90%, compared to controls (p < 0.05). The new nanocomposites produced excellent cell viability matching commercial control (p > 0.05).

CONCLUSIONS

Bioactive L.S.S. antibacterial nanocomposites with nCaF2 and NACP had excellent bioactivity without compromising mechanical and cytocompatible properties. The new nanocomposites are promising for a wide range of dental restorations by improving marginal integrity by reducing shrinkage stress, defending tooth structures, and minimizing cariogenic biofilms.

Mutanase from Trichoderma harzianum inductively Produced by Mutan: Short-Term Treatment to Degrade Mature Streptococcus mutans Biofilm

This study aimed to evaluate the disruptive effect of fungal mutanase against cariogenic biofilm after short-term treatment. For that, mature Streptococcus mutans biofilms (n = 9) were exposed to active or inactivated enzymes produced by Trichoderma harzianum for 1 min, two times per day. Biofilms were analyzed by amount of matrix water-insoluble polysaccharides, bacterial viability, acidogenicity, and morphology by scanning electron microscopy (SEM). The group treated with active enzymes (AE) had a significantly lower amount of insoluble polysaccharides (893.30 ± 293.69) when compared to the negative control group (NaCl, 2192.59 ± 361.96), yet no significant difference was found when comparing to the positive control group (CHX, 436.82 ± 151.07). Also, there was no significant effect on bacteria metabolism and viability (P-value < 0.05). Data generated by the quantitative analysis were confirmed through scanning electron microscopy images. Thus, fungal mutanase degraded the biofilm after a short-term treatment without interfering with bacterial viability and metabolism. Such findings offer insight to the development of routine oral care products containing this input.

Current antibacterial agents in dental bonding systems: a comprehensive overview

Dental caries is mainly caused by oral biofilm acid, and the most common dental restoration treatment is composite dental restorations. The main cause of failure is secondary caries adjacent to the restoration. Long-term survival of dental materials is improved by the presence of antibacterial agents, which selectively inhibit bacterial growth or survival. Chemical, natural and biomaterials have been studied for their antimicrobial activities and antibacterial bonding agents have been improved. Their usage has been increased to inhibit the growth of invading and residual bacteria in the oral cavity, as biofilm accumulation increases the risk of treatment failure. In this article, the success and applications of antibacterial agents are discussed in dental bonding systems.

Exploring the Potential of Bee-Derived Antioxidants for Maintaining Oral Hygiene and Dental Health: A Comprehensive Review

Honey bee products comprise various compounds, including honey, propolis, royal jelly, bee pollen, bee wax and bee venom, which have long been recognized for their pharmacological and health-promoting benefits. Scientists have discovered that periodontal disorders stem from dental biofilm, an inflammatory response to bacterial overgrowth produced by dysbiosis in the oral microbiome. The bee products have been investigated for their role in prevention of oral diseases, which are attributed to a myriad of biologically active compounds including flavonoids (pinocembrin, catechin, caffeic acid phenethyl ester (CAPE) and galangin), phenolic acids (hydroxybenzoic acid, hydroxycinnamic acid, p-coumaric, ellagic, caffeic and ferulic acids) and terpenoids. This review aims to update the current understanding of role of selected bee products, namely, honey, propolis and royal jelly, in preventing oral diseases as well as their potential biological activities and mechanism of action in relation to oral health have been discussed. Furthermore, the safety of incorporation of bee products is also critically discussed. To summarize, bee products could potentially serve as a therapy option for people suffering from a variety of oral disorders.

Microbial Biofilm: A Review on Formation, Infection, Antibiotic Resistance, Control Measures, and Innovative Treatment

Biofilm is complex and consists of bacterial colonies that reside in an exopolysaccharide matrix that attaches to foreign surfaces in a living organism. Biofilm frequently leads to nosocomial, chronic infections in clinical settings. Since the bacteria in the biofilm have developed antibiotic resistance, using antibiotics alone to treat infections brought on by biofilm is ineffective. This review provides a succinct summary of the theories behind the composition of, formation of, and drug-resistant infections attributed to biofilm and cutting-edge curative approaches to counteract and treat biofilm. The high frequency of medical device-induced infections due to biofilm warrants the application of innovative technologies to manage the complexities presented by biofilm.

Biological considerations of dental materials as orifice barriers for restoring root-filled teeth

There is ample published literature regarding the technical aspects of restoring root-filled teeth, but little concerning the biological impacts, consequences, and criteria for the selection of direct restorative materials following endodontic treatment. The provision of an effective coronal seal in addition to a sound root filling is known to be important in the prevention of root canal infection. This review seeks to explore the evidence concerning the selection of dental materials in the restoration of root-filled teeth, specifically with a close examination of the properties of commonly used materials as orifice barriers. © 2023 Australian Dental Association.

Streptococcus mutans dexA affects exopolysaccharides production and biofilm homeostasis

OBJECTIVES

The study aimed to evaluate the role of Streptococcus mutans (S. mutans) dexA gene on biofilm structure and microecological distribution in multispecies biofilms.

MATERIALS AND METHODS

A multispecies biofilm model consisting of S. mutans and its dexA mutants, Streptococcus gordonii (S. gordonii) and Streptococcus sanguinis (S. sanguinis) was constructed, and bacterial growth, biofilm architecture and microbiota composition were determined to study the effect of the S. mutans dexA on multispecies biofilms.

RESULTS

Our results showed that either deletion or overexpression of S. mutans dexA had no effect on the planktonic growth of bacterium, while S. mutans dominated in the multispecies biofilms to form cariogenic biofilms. Furthermore, we revealed that the SmudexA+ group showed structural abnormality in the form of more fractures and blank areas. The morphology of the SmudexA group was sparser and more porous, with reduced and less agglomerated exopolysaccharides scaffold. Interestingly, the microbiota composition analysis provided new insights that the inhibition of S. gordonii and S. sanguinis was alleviated in the SmudexA group compared to the significantly suppressed condition in the other groups.

CONCLUSION

In conclusion, deletion of S. mutans dexA gene re-modules biofilm structure and microbiota composition, thereby leading to decreased cariogenicity. Thus, the S. mutans dexA may be an important target for regulating the cariogenicity of dental plaque biofilms, expecting to be a probiotic for caries control.

Disruption of biofilms in periodontal disease through the induction of phase transition by cationic dextrans

Biofilm of oral pathogenic microorganisms induced by their multiplication and coaggregation would lead to periodontitis. In biofilms, the extracellular polymeric substances (EPS) as a protective shield encapsulates the individual bacteria, protecting them against attack. To alleviate periodontal disease, disrupting the EPS of pathogenic bacteria is crucial and challenging. Based on the sufficient capacity of disorganizing EPS of our designed cationic dextrans, we hypothesized that these polymers could be competent in relieving periodontitis. We validated that cationic dextrans could induce the phase transition of EPS in biofilms, especially the Porphyromonas gingivalis (P. gingivalis), a keystone periodontal pathogen, thus effectively destroying biofilm in vitro. More importantly, satisfactory in vivo treatment was achieved in a rat periodontal disease model. In summary, the study exploited a practical and effective strategy to treat periodontitis with cationic dextrans' powerful biofilm-controlling potential. STATEMENT OF SIGNIFICANCE: Periodontal disease is closely related to dental plaque biofilms on the tooth surface. The biofilm forms gel structures and shields the bacteria underneath, thus protecting oral pathogens from traditional anti-bacterial reagents. Due to limited penetration into gel, the efficacy of these reagents in biofilm elimination is restricted. Our designed cationic dextran could wipe out the coverage of gel-like EPS to disperse encapsulated bacteria. Such superior capacity endowed them with satisfactory effect in disrupting biofilm. Notably, in a rat periodontitis model, cationic dextrans dramatically suppressed alveolar bone loss and alleviated periodontal inflammation by controlling dental plaque. Given the increasing global concerns about periodontal disease, it's worth expanding the application of cationic dextrans both scientifically and clinically.

Revisiting the Therapeutic Effects of Essential Oils on the Oral Microbiome

The extensive use of antibiotics has resulted in the development of drug-resistant bacteria, leading to a decline in the efficacy of traditional antibiotic treatments. Essential oils (EOs) are phytopharmaceuticals, or plant-derived compounds, that possess beneficial properties such as anti-inflammatory, antibacterial, antimicrobial, antiviral, bacteriostatic, and bactericidal effects. In this review, we present scientific findings on the activity of EOs as an alternative therapy for common oral diseases. This narrative review provides a deeper understanding of the medicinal properties of EOs and their application in dentistry. It not only evaluates the effectiveness of these oils as antibacterial agents against common oral bacteria but also covers general information such as composition, methods of extraction, and potential toxicity. Further nonclinical and clinical studies must be conducted to determine their potential use and safety for treating oral diseases.

Dental plaque-inspired versatile nanosystem for caries prevention and tooth restoration

Dental caries is one of the most prevalent human diseases resulting from tooth demineralization caused by acid production of bacteria plaque. It remains challenges for current practice to specifically identify, intervene and interrupt the development of caries while restoring defects. In this study, inspired by natural dental plaque, a stimuli-responsive multidrug delivery system (PMs@NaF-SAP) has been developed to prevent tooth decay and promote enamel restoration. Classic spherical core-shell structures of micelles dual-loaded with antibacterial and restorative agents are self-assembled into bacteria-responsive multidrug delivery system based on the pH-cleavable boronate ester bond, followed by conjugation with salivary-acquired peptide (SAP) to endow the nanoparticle with strong adhesion to tooth enamel. The constructed PMs@NaF-SAP specifically adheres to tooth, identifies cariogenic conditions and intelligently releases drugs at acidic pH, thereby providing antibacterial adhesion and cariogenic biofilm resistance, and restoring the microarchitecture and mechanical properties of demineralized teeth. Topical treatment with PMs@NaF-SAP effectively diminishes the onset and severity of caries without impacting oral microbiota diversity or surrounding mucosal tissues. These findings demonstrate this novel nanotherapy has potential as a promising biomedical application for caries prevention and tooth defect restoration while resisting biofilm-associated diseases in a controlled manner activated by pathological bacteria.

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Nanomaterials can adhere to tooth and target acidic biofilms specifically.

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Application of caries prevention and tooth defect restoration.

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Guidance for the innovation of the existing post-defect restoration strategies.

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The multidrug delivery system exerts antibacterial and restorative abilities on demand.

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Bacteria-responsive system resists biofilm-associated diseases in a controlled manner.

Antimicrobial photodynamic therapy mediated by methylene blue-loaded polymeric micelles against Streptococcus mutans and Candida albicans biofilms

BACKGROUND

Streptococcus mutans and Candida albicans can colonize the teeth, the oral cavity as biofilm and can cause oral infections. Thus, strategies to prevent and control oral biofilms are requested. The present study aims the development and characterization of methylene blue (MB)-loaded polymeric micelles for antimicrobial photodynamic therapy (aPDT) against Streptococcus mutans and Candida albicans biofilms METHODS: MB-loaded polymeric micelles were produced and characterized by particle size, polydispersity index, morphology, zeta potential, stability, MB release profile, and antimicrobial effect against S. mutans and C. albicans biofilms.

RESULTS

MB-loaded polymeric micelles showed a reduced particle size, moderate polydisperse profile, spherical and neutral shape, which demonstrated to be promising features to allow micelles penetration into biofilms. Antimicrobial effect against bacterial and yeast biofilms was demonstrated once MB was irradiated by light under 660 nm (aPDT). Furthermore, MB-loaded polymeric micelles showed significant inhibition of S. mutans and C. albicans biofilms. Furthermore, the treatment with MB-micelles incubated with high pre-incubation times (15 and 30 min) were more effective than 5 min. It can be explained by the time required for this nanosystem to penetrate the innermost layer of biofilms and release MB for aPDT.

CONCLUSION

MB-loaded polymeric micelles can effectively decrease the bacteria and yeast viability and it may cause positive impacts in the clinical practice. Thus, the developed formulation showed potential in the treatment to remove oral biofilms, but clinical studies are needed to confirm its potential.

Enhancement of chlorhexidine activity against planktonic and biofilm forms of oral streptococci by two Croton spp. essential oils from the Caatinga biome

This work investigates the ability of two Croton spp. essential oils (EO) to enhance chlorhexidine (CHX) activity against oral streptococci. EO's chemical composition of Croton argyrophyllus and C. pluriglandulosus was determined by GC-MS/FID. The microbial growth kinetics and minimum inhibitory concentration (MIC) of EOs and CHX were determined, followed by their synergism against S. mutans UA159 and ATCC 25175, S. salivarius ATCC 7073 and S. sp. ATCC 15300. The microplate-based method was used to determine the EO/CHX activity against 24-h-old biofilms. The major compounds were α-pinene (54.74%) and bicyclogermacrene (16.08%) for EOAr and 1,8-cineole (17.41%), methyleugenol (16.06%) and elemicin (15.99%) for EOPg. Both EO had MIC around 16,000 µg/mL. EOs/CHX presented a synergistic effect against most strains (FICi from 0.133 to 0.375), and OE/CHX-treated biofilms showed a reduction in biomass and cell viability compared to CHX, only (p < 0.01). Thus, the EOs works as natural adjuvants for CHX.

pH-activated antibiofilm strategies for controlling dental caries

Dental biofilms are highly assembled microbial communities surrounded by an extracellular matrix, which protects the resident microbes. The microbes, including commensal bacteria and opportunistic pathogens, coexist with each other to maintain relative balance under healthy conditions. However, under hostile conditions such as sugar intake and poor oral care, biofilms can generate excessive acids. Prolonged low pH in biofilm increases proportions of acidogenic and aciduric microbes, which breaks the ecological equilibrium and finally causes dental caries. Given the complexity of oral microenvironment, controlling the acidic biofilms using antimicrobials that are activated at low pH could be a desirable approach to control dental caries. Therefore, recent researches have focused on designing novel kinds of pH-activated strategies, including pH-responsive antimicrobial agents and pH-sensitive drug delivery systems. These agents exert antibacterial properties only under low pH conditions, so they are able to disrupt acidic biofilms without breaking the neutral microenvironment and biodiversity in the mouth. The mechanisms of low pH activation are mainly based on protonation and deprotonation reactions, acids labile linkages, and H⁺-triggered reactive oxygen species production. This review summarized pH-activated antibiofilm strategies to control dental caries, concentrating on their effect, mechanisms of action, and biocompatibility, as well as the limitation of current research and the prospects for future study.

Investigation of the Antibacterial, Anti-Biofilm, and Antioxidative Effect of Piper betle Leaf Extract against Bacillus gaemokensis MW067143 Isolated from Dental Caries, an In Vitro-In Silico Approach

Among oral diseases, dental caries is one of the most frequent to affect human health. The current research work aimed to ascertain the antibacterial, anti-biofilm, and antioxidative potential of Piper betle leaf extract against bacteria isolated from dental caries. Analysis for the presence of phytochemical compounds revealed compounds, such as tannins, steroids, phenolic compounds, and alkaloids, which were also confirmed by TLC and FTIR. GC-MS analysis elucidated the presence of 20 phytocompounds, among which were some well-reported bioactive compounds. The chloroform extract of P. betle demonstrated good antibacterial activity (7 mm) and minimum inhibitory concentration (MIC) (100 mg mL^-1) against Bacillus gaemokensis MW067143, which was the frequent biofilm producer among isolated bacterial strains. Fractions of the extract were isolated through column chromatography, after which the antibacterial activity was again evaluated. Spirost-8-en-11-one,3-hydroxy(3β,5α,14β,20β,22β,25R), an oxosteroid in nature, was observed to exhibit remarkable antibacterial potential (12 mm) against B. gaemokensis. Bacterial cells treated with P. betle extract had elevated SOD, APOX, POX, and GR activity, while its proteolytic activity against whole bacterial proteins was pronounced with the suppression of several proteins (50, 40, 15, and 10 kDa) in SDS-PAGE. Bacterial cells treated with P. betle extract demonstrated decreased growth, while the extract was also observed to exhibit inhibition of biofilm formation (70.11%) and demolition of established B. gaemokensis biofilms (57.98%). SEM analysis revealed significant changes to bacterial morphology post treatment with P. betle, with cellular disintegration being prominent. In silico network pharmacology analysis elucidated proteins like ESR1 and IL6 to be majorly involved in biological pathways of dental caries, which also interact with the protective ability of P. betle. Gene Ontology (GO) terms and KEGG pathways were also screened using enrichment analysis. Molecular docking demonstrated the highest binding affinity of Spirost-8-en-11-one,3-hydroxy-,(3β,5α,14β,20β,22β,25R) with bacterial proteins FabI (-12 kcal/mol), MurB (-17.1 kcal/mol), and FtsZ (-14.9 kcal/mol). Therefore, it is suggested that P. betle can serve a potentially therapeutic role and could be used in the preparation of herbal formulations for managing bacterial flora.

L-arginine-containing mesoporous silica nanoparticles embedded in dental adhesive (Arg@MSN@DAdh) for targeting cariogenic bacteria

Dental caries is the major biofilm-mediated oral disease in the world. The main treatment to restore caries lesions consists of the use of adhesive resin composites due to their good properties. However, the progressive degradation of the adhesive in the medium term makes possible the proliferation of cariogenic bacteria allowing secondary caries to emerge. In this study, a dental adhesive incorporating a drug delivery system based on L-arginine-containing mesoporous silica nanoparticles (MSNs) was used to release this essential amino acid as a source of basicity to neutralize the harmful acidic conditions that mediate the development of dental secondary caries. The in vitro and bacterial culture experiments proved that L-arginine was released in a sustained way from MSNs and diffused out from the dental adhesive, effectively contributing to the reduction of the bacterial strains Streptococcus mutans and Lactobacillus casei. Furthermore, the mechanical and bonding properties of the dental adhesive did not change significantly after the incorporation of L-arginine-containing MSNs. These results are yielding glimmers of promise for the cost-effective prevention of secondary caries.

Silver Nanoparticles Produced by Laser Ablation and Re-Irradiation Are Effective Preventing Peri-Implantitis Multispecies Biofilm Formation

Implant-associated infection due to biofilm formation is a growing problem. Given that silver nanoparticles (Ag-NPs) have shown antibacterial effects, our goal is to study their effect against multispecies biofilm involved in the development of peri-implantitis. To this purpose, Ag-NPs were synthesized by laser ablation in de-ionized water using two different lasers, leading to the production of colloidal suspensions. Subsequently, part of each suspension was subjected to irradiation one and three times with the same laser source with which it was obtained. Ag-NPs were immobilized on the surface of titanium discs and the resultant materials were compared with unmodified titanium coupons. Nanoparticles were physico-chemically analysed to determine their shape, crystallinity, chemical composition, and mean diameter. The materials were incubated for 90 min or 48 h, to evaluate bacterial adhesion or biofilm formation respectively with Staphylococcus aureus or oral mixed bacterial flora composed of Streptococcus oralis, Actinomyces naeslundii, Veionella dispar, and Porphyromonas gingivalis. Ag-NPs help prevent the formation of biofilms both by S. aureus and by mixed oral bacterial flora. Nanoparticles re-irradiated three times showed the biggest antimicrobial effects. Modifying dental implants in this way could prevent the development of peri-implantitis.

Cymbopogon citratus Essential Oil Increases the Effect of Digluconate Chlorhexidine on Microcosm Biofilms

The aim of this study was to evaluate the effect of the Cymbopogon citratus essential oil and its association with chlorhexidine on cariogenic microcosm biofilm composition and acidogenicity. Minimum inhibitory and bactericide concentrations from the essential oil and chlorhexidine were determined by broth microdilution assay. Microcosms (polymicrobial) biofilms were produced on glass coverslips, using inoculum from human saliva in McBain culture medium (0.5% sucrose exposure for 6 h/day) for 3 days in 24-well plates. The biofilms were treated twice a day and their composition was evaluated by microorganism quantification. The acidogenicity was evaluated by measuring the pH of the spent culture medium in contact with the biofilm. Overall, the association of C. citratus and chlorhexidine reduced total bacterial counts and aciduric bacteria (maximum reduction of 3.55 log UFC/mL) in microcosm biofilms. This group also presented the lowest acidogenicity even when exposed to sucrose-containing medium. C. citratus essential oil increases the effect of digluconate chlorhexidine on microcosm biofilms. Based on these findings, this study can contribute to the development of new formulations that might allow for the use of mouthwashes for a shorter period, which may reduce undesirable effects and increase patient compliance to the treatment.

Comparative Evaluation of Antibacterial Efficacy of Emblica Officinalis Lollipop Against Streptococcus Mutans Counts in Institutionalized Visually Impaired Children

Background

Among the 1.21 billion population of India, 26.8 million individuals have disabilities, and around five million are visually impaired. These children encounter problems related to oral health maintenance, thus further leading to dental problems. Even though Pediatric dentists treat visually impaired children for their oral problems, they emphasize mainly on the prevention of dental caries. Dental caries has a multifactorial etiology, and dentists are unable to find a complete solution for its prevention. However, reducing Streptococcus mutans has been seen to reduce the caries rate in the past. The use of the herbal product Emblica officinalis to reduce Streptococcus mutans levels has been documented. An affordable delivery system is required to use Emblica officinalis for its anticaries action. Thus, a unique delivery system of herbal sugar-free lollipops containing Emblica officinalis extract was made and can effectively deliver antimicrobial action in visually impaired children.

Aim

To evaluate the antibacterial efficacy of Emblica officinalis lollipop on Streptococcus mutans counts and pH levels in institutionalized visually impaired children.

Method

A total of 60 institutionalized visually impaired children (age: 4 to 14 years) were selected. The study consisted of two groups (experimental “Emblica officinalis lollipop” and control “placebo lollipop”), and the children were divided equally into both groups. Children from the study and control groups were subjected to the respective lollipops twice daily for seven days. Streptococcus mutans count and pH count were evaluated at baseline and after seven days post-intervention of the respective lollipop.

Results

The results showed that in both groups, Streptococcus mutans count was reduced post-intervention. However, the efficacy of the study group (Emblica officinalis lollipop) in inhibiting the Streptococcus mutans count was better than the control group (placebo lollipop). An increase in the pH level was seen post-intervention for both the study and control groups. And on the intergroup comparison, no statistical significance was found.

Conclusion

The use of Emblica officinalis lollipop is effective in inhibiting the Streptococcus mutans count when compared with the placebo lollipop. While marginal pH change was seen in both groups. Thus, the herbal modality most acceptable without any pharmaceutical concerns should be chosen. Emblica officinalis lollipops can be used in institutionalized visually impaired children to reduce the oral Streptococcus mutans count and maintain a healthy oral cavity.

Natural products from traditional medicine as promising agents targeting at different stages of oral biofilm development

Oral cavity is an ideal habitat for more than 1,000 species of microorganisms. The diverse oral microbes form biofilms over the hard and soft tissues in the oral cavity, affecting the oral ecological balance and the development of oral diseases, such as caries, apical periodontitis, and periodontitis. Currently, antibiotics are the primary agents against infectious diseases; however, the emergence of drug resistance and the disruption of oral microecology have challenged their applications. The discovery of new antibiotic-independent agents is a promising strategy against biofilm-induced infections. Natural products from traditional medicine have shown potential antibiofilm activities in the oral cavity with high safety, cost-effectiveness, and minimal adverse drug reactions. Aiming to highlight the importance and functions of natural products from traditional medicine against oral biofilms, here we summarized and discussed the antibiofilm effects of natural products targeting at different stages of the biofilm formation process, including adhesion, proliferation, maturation, and dispersion, and their effects on multi-species biofilms. The perspective of antibiofilm agents for oral infectious diseases to restore the balance of oral microecology is also discussed.

The Current Antimicrobial and Antibiofilm Activities of Synthetic/Herbal/Biomaterials in Dental Application

Herbal and chemical products are used for oral care and biofilm treatment and also have been reported to be controversial in the massive trials conducted in this regard. The present review is aimed at evaluating the potential of relevant herbal and chemical products and comparing their outcomes to conventional oral care products and summarizing the current state of evidence of the antibiofilm properties of different products by evaluating studies from the past eleven years. Chlorhexidine gluconate (CHX), essential oils (EOs), and acetylpyridinium chloride were, respectively, the most commonly studied agents in the included studies. As confirmed by all systematic reviews, CHX and EO significantly control the plaque formation and gingival indices. Fluoride is another interesting reagent in oral care products that has shown promising results of oral health improvement, but the evidence quality needs to be refined. The synergy between natural plants and chemical products should be targeted in the future to accede to the formation of new, efficient, and healthy anticaries strategies. Moreover, to discover their biofilm-interfering or biofilm-inhibiting activities, effective clinical trials are needed. In this review article, therapeutic applications of herbal/chemical materials in oral biofilm infections are discussed in recent years (2010-2022).

Can metagenomics unravel the impact of oral bacteriome in human diseases?

Oral microbial ecosystems are vital in maintaining the health of the oral cavity and the entire body. Oral microbiota is associated with the progression of oral diseases such as dental caries, periodontal diseases, head and neck cancer, and several systemic diseases such as cardiovascular disease, rheumatoid arthritis, adverse pregnancy outcomes, diabetes, lung infection, colorectal cancer, and pancreatic cancer. Buccal mucosa, tongue dorsum, hard palate, saliva, palatine tonsils, throat, keratinized gingiva, supra-gingival plaque, subgingival plaque, dentures, and lips are microbial habitats of the oral cavity. Porphyromonas gingivalis may have a role in the development of periodontal diseases, oral cancer, diabetes, and atherosclerotic disease. Fusobacterium nucleatum showed a higher abundance in periodontal diseases, oral and colon cancer, adverse pregnancy outcomes, diabetes, and rheumatoid arthritis. The higher abundance of Prevotella intermedia is typical in periodontal diseases, rheumatoid arthritis, and adverse pregnancy outcome. S. salivarius displayed higher abundance in both dental caries and OSCC. Oral bacteria may influence systemic diseases through inflammation by releasing pro inflammatory cytokines. Identification of oral bacteria using culture-dependent approaches and next-generation sequencing-based metagenomic approaches is believed to significantly identify the therapeutic targets and non-invasive diagnostic indicators in different human diseases. Oral bacteria in saliva could be exploited as a non-invasive diagnostic indicator for the early detection of oral and systemic disorders. Other therapeutic approaches such as the use of probiotics, green tea polyphenol, cold atmospheric plasma (CAP) therapy, antimicrobial photodynamic therapy, and antimicrobial peptides are used to inhibit the growth of biofilm formation by oral bacteria.

Nanoparticles in Endodontics Disinfection: State of the Art

Endodontic-related diseases constitute the fourth most expensive pathologies in industrialized countries. Specifically, endodontics is the part of dentistry focused on treating disorders of the dental pulp and its consequences. In order to treat these problems, especially endodontic infections, dental barriers and complex root canal anatomy should be overcome. This constitutes an unmet medical need since the rate of successful disinfection with the currently marketed drugs is around 85%. Therefore, nanoparticles constitute a suitable alternative in order to deliver active compounds effectively to the target site, increasing their therapeutic efficacy. Therefore, in the present review, an overview of dental anatomy and the barriers that should be overcome for effective disinfection will be summarized. In addition, the versatility of nanoparticles for drug delivery and their specific uses in dentistry are comprehensively discussed. Finally, the latest findings, potential applications and state of the art nanoparticles with special emphasis on biodegradable nanoparticles used for endodontic disinfection are also reviewed.

Dental Materials for Oral Microbiota Dysbiosis: An Update

The balance or dysbiosis of the microbial community is a major factor in maintaining human health or causing disease. The unique microenvironment of the oral cavity provides optimal conditions for colonization and proliferation of microbiota, regulated through complex biological signaling systems and interactions with the host. Once the oral microbiota is out of balance, microorganisms produce virulence factors and metabolites, which will cause dental caries, periodontal disease, etc. Microbial metabolism and host immune response change the local microenvironment in turn and further promote the excessive proliferation of dominant microbes in dysbiosis. As the product of interdisciplinary development of materials science, stomatology, and biomedical engineering, oral biomaterials are playing an increasingly important role in regulating the balance of the oral microbiome and treating oral diseases. In this perspective, we discuss the mechanisms underlying the pathogenesis of oral microbiota dysbiosis and introduce emerging materials focusing on oral microbiota dysbiosis in recent years, including inorganic materials, organic materials, and some biomolecules. In addition, the limitations of the current study and possible research trends are also summarized. It is hoped that this review can provide reference and enlightenment for subsequent research on effective treatment strategies for diseases related to oral microbiota dysbiosis.

Effects of fibular strut augmentation for the open reduction and internal fixation of proximal humeral fractures: a systematic review and meta-analysis

BACKGROUND

There is still a lack of remarkable consensus regarding the clinical efficacy of the application of fibular strut augmentation (FSA) combined with a locking plate for proximal humeral fractures. A systematic review and meta-analysis to assess the effect of the use of FSAs in open reduction and internal fixation of proximal humeral fractures was conducted.

METHODS

A literature search was conducted in PubMed, Embase, Cochrane, Web of Science Core Collection, and ClinicalTrials.gov to identify trials that compared the clinical outcomes of proximal humeral fractures treated using a locking plate with or without FSA. The primary outcome measures were postoperative complications, radiographical findings, functional recovery scores, and postoperative range of motion (ROM). Data were pooled and analysed using a random-effects model based on the Der Simonian and Laird method.

RESULTS

Eight studies involving 596 participants were included for further analysis. Compared with using a locking plate independently, the additional application of FSA was associated with the likelihood of lower risk of overall complications (OR 0.37; 95% CI 0.22-0.65; I² = 12.22%; 95% PI 0.14-0.98) and the rate of patients with orthopaedic complications (OR 0.48; 95% CI 0.25-0.92; I² = 7.52%; 95% PI 0.16-1.45), less changes in postoperative humeral head height (MD - 2.40; 95% CI - 2.49 to - 2.31; I² = 0.00%; 95% PI - 2.61 to - 2.20) and the neck-shaft angle (MD - 6.30; 95% CI - 7.23 to - 5.36; I² = 79.32%; 95% PI - 10.06 to - 2.53), superior functional outcomes (Constant-Murley score: MD 5.07; 95% CI 3.40 to 6.74; I² = 0.00%; 95% PI 2.361-7.78; American Shoulder and Elbow Surgeons Score: MD 5.08; 95% CI 3.67 to 6.49; I² = 0.00%; 95% PI 1.98-8.18), and better postoperative ROM in terms of forward elevation and external rotation. However, the evidence regarding postoperative abduction was insufficient.

CONCLUSION

Meta-analytic pooling of current evidence showed a significant association between the application of FSAs and favourable clinical outcomes in terms of postoperative complications, radiographical findings, functional recovery, and postoperative elevation and external rotation.

Phytochemical Profile of Antibacterial Agents from Red Betel Leaf (Piper crocatum Ruiz and Pav) against Bacteria in Dental Caries

Based on data from The Global Burden of Disease Study in 2016, dental and oral health problems, especially dental caries, are a disease experienced by almost half of the world’s population (3.58 billion people). One of the main causes of dental caries is the pathogenesis of Streptococcus mutans. Prevention can be achieved by controlling S. mutans using an antibacterial agent. The most commonly used antibacterial for the treatment of dental caries is chlorhexidine. However, long-term use of chlorhexidine has been reported to cause resistance and some side effects. Therefore, the discovery of a natural antibacterial agent is an urgent need. A natural antibacterial agent that can be used are herbal medicines derived from medicinal plants. Piper crocatum Ruiz and Pav has the potential to be used as a natural antibacterial agent for treating dental and oral health problems. Several studies reported that the leaves of P. crocatum Ruiz and Pav contain secondary metabolites such as essential oils, flavonoids, alkaloids, terpenoids, tannins, and phenolic compounds that are active against S. mutans. This review summarizes some information about P. crocatum Ruiz and Pav, various isolation methods, bioactivity, S. mutans bacteria that cause dental caries, biofilm formation mechanism, antibacterial properties, and the antibacterial mechanism of secondary metabolites in P. crocatum Ruiz and Pav.

Nutrient Sensing and Biofilm Modulation: The Example of L-arginine in Pseudomonas

Bacterial biofilm represents a multicellular community embedded within an extracellular matrix attached to a surface. This lifestyle confers to bacterial cells protection against hostile environments, such as antibiotic treatment and host immune response in case of infections. The Pseudomonas genus is characterised by species producing strong biofilms difficult to be eradicated and by an extraordinary metabolic versatility which may support energy and carbon/nitrogen assimilation under multiple environmental conditions. Nutrient availability can be perceived by a Pseudomonas biofilm which, in turn, readapts its metabolism to finally tune its own formation and dispersion. A growing number of papers is now focusing on the mechanism of nutrient perception as a possible strategy to weaken the biofilm barrier by environmental cues. One of the most important nutrients is amino acid L-arginine, a crucial metabolite sustaining bacterial growth both as a carbon and a nitrogen source. Under low-oxygen conditions, L-arginine may also serve for ATP production, thus allowing bacteria to survive in anaerobic environments. L-arginine has been associated with biofilms, virulence, and antibiotic resistance. L-arginine is also a key precursor of regulatory molecules such as polyamines, whose involvement in biofilm homeostasis is reported. Given the biomedical and biotechnological relevance of biofilm control, the state of the art on the effects mediated by the L-arginine nutrient on biofilm modulation is presented, with a special focus on the Pseudomonas biofilm. Possible biotechnological and biomedical applications are also discussed.

Three-dimensional analysis of mandible ramus morphology and transverse stability after intraoral vertical ramus osteotomy

Objectives

The purpose of this study was to investigate short- and long-term postoperative changes of both morphology and transverse stability in mandibular ramus after intraoral vertical ramus osteotomy (IVRO) in patients with jaw deformity using three-dimensional (3D) orthognathic surgery planning treatment software for measurement of distances and angles.

Study design

This retrospective study included consecutive patients with skeletal Class III malocclusion who had undergone intraoral vertical ramus osteotomy and computed tomography images before (T0), immediately after (T1), and 1 year after (T2) surgery. Reference points, reference lines and evaluation items were designated on the reconstructed 3D surface models to measure distances, angles and volume. The average values at T0, T1, T2 and time-dependent changes in variables were obtained.

Results

After surgery, the condylar length, ramal height, mandibular body length and mandibular ramus volume were significantly decreased (P < 0.01), while clinically insignificant change was observed from T1 to T2. The angular length was increased immediately after surgery (P < 0.05), but it was decreased 1 year after surgery (P < 0.05). Lateral ramal inclination showed significant increase after surgery (P < 0.05) and maintained at T2.

Conclusion

Changes in the morphology of the mandibular ramus caused by IVRO do not obviously bring negative effect on facial appearance. Furthermore, despite position and angle of mandibular ramus changed after IVRO, good transverse stability was observed postoperatively. Therefore, IVRO technique can be safely used without compromising esthetic results.

A Potential “Vitaminic Strategy” against Caries and Halitosis

Streptococcus mutans and Fusobacterium nucleatum are two key bacteria of the oral microbiota. Due to their ability to form biofilms on oral tissues, they are both involved in the onset of the most common oral diseases. F. nucleatum is also the principal producer of hydrogen sulfide (H2S), causative of the awkward bad breath of halitosis. In this study, the oral product Vea® Oris, made by vitamin E and capric/caprylic acid only, was evaluated as a potential treatment for the most common oral diseases. Different concentrations of the product were tested against both S. mutans and F. nucleatum. The effect on planktonic and biofilm growth was investigated for both strains, and for F. nucleatum, the influence on H2S production was evaluated. From our data, the product did not relevantly reduce the planktonic growth of both strains, whereas it validly counteracted biofilm assemblage. Moreover, an interesting trend of H2S reduction was highlighted. Overall, these results suggested, on the one hand, a synergistic antimicrobial–antibiofilm action of two Vea® Oris components and, together, potential modulation activity on H2S production. However, the study should be implemented to confirm these only preliminary findings, certainly extending the panel of tested bacteria and using alternative methods of detection.

Inhibition efficiency of 304-Cu stainless steel against oral bacterial biofilm

PURPOSE

This study aims to evaluate the antibacterial properties of 304 Cu-bearing stainless steel (SS) with different Cu contents (0, 2.5, 4.5 wt.%) against oral biofilms of Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), and their mixture.

METHODS

Bacterial biofilms on the surface of 304-Cu SS were characterized by plate counting, 4', 6-diamidino-2-phenylindole (DAPI) staining with aid of sanning electron microscopy (SEM) and 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT). In addition, the inhibition zone method was also employed to evaluate the antibacterial properties of 304-Cu SS. Cell Counting Kit-8 (CCK-8) and flow cytometry were used to assess the cytotoxicity and apoptosis rate of 304-Cu SS, respectively.

RESULTS

304-4.5Cu SS could effectively inhibit the attachment, formation, activity, and metabolism of bacterial biofilm, possessing the best antibacterial properties exceeding 99.9% of antibacterial rate against S. mutans, S. sanguinis, and their mixture. The diameters of inhibition zones to S. mutans and S. sanguinis on the surface of 304-4.5Cu SS were 21.7 and 14.7 mm, respectively. The results of cell experiments in vitro showed that both 304-2.5Cu SS and 304-4.5Cu SS had no evident cytotoxicity with an identical grade 1. The apoptosis rate exhibited a gradually increased tendency with increase of the Cu content in 304 SS.

CONCLUSIONS

304-4.5Cu SS without cytotoxic effect on NIH3T3 cells has obvious antibacterial activity against S. mutans, S. sanguinis and their mixture.

CLINICAL SIGNIFICANCE

The Cu-bearing stainless steel provides a new solution to be used as oral orthodontic devices for inhibiting oral microflora imbalance and enamel demineralization.

Microbial Biofilm Decontamination on Dental Implant Surfaces: A Mini Review

Introduction

After insertion into the bone, implants osseointegrate, which is required for their long-term success. However, inflammation and infection around the implants may lead to implant failure leading to peri-implantitis and loss of supporting bone, which may eventually lead to failure of implant. Surface chemistry of the implant and lack of cleanliness on the part of the patient are related to peri-implantitis. The only way to get rid of this infection is decontamination of dental implants.

Objective

This systematic review intended to study decontamination of microbial biofilm methods on titanium implant surfaces used in dentistry.

Methods

The electronic databases Springer Link, Science Direct, and PubMed were explored from their inception until December 2020 to identify relevant studies. Studies included had to evaluate the efficiency of new strategies either to prevent formation of biofilm or to treat matured biofilm on dental implant surfaces.

Results and Discussion

In this systematic review, 17 different groups of decontamination methods were summarized from 116 studies. The decontamination methods included coating materials, mechanical cleaning, laser treatment, photodynamic therapy, air polishing, anodizing treatment, radiation, sonication, thermal treatment, ultrasound treatment, chemical treatment, electrochemical treatment, antimicrobial drugs, argon treatment, and probiotics.

Conclusion

The findings suggest that most of the decontamination methods were effective in preventing the formation of biofilm and in decontaminating established biofilm on dental implants. This narrative review provides a summary of methods for future research in the development of new dental implants and decontamination techniques.

Polymeric implants with drug-releasing capabilities: a mapping review of laboratory research

PURPOSE

To provide a systematic map of the nature and extent of preclinical research concerning drug-releasing polymeric implants.

SIGNIFICANCE

By summarizing available data, this mapping review can guide the development of new drug-delivery devices.

METHODS

In-vitro studies assessing drug-delivery implants were reviewed. A study protocol was registered at Open Science Framework. The association of polymers with prominent drugs, manufacturing processes, geometries, treatments, and anatomical locations was assessed using the VOSviewer software. The release periods were also evaluated.

RESULTS

A total of 423 articles, published between 1975 and 2020, were included and grouped into a framework with nine main categories. More than half of studies were published between 2010 and 2020. Among 201 individual polymers or combinations, the most investigated were PLGA, PCL, PLA, Silicone (SIL), EVA, and PU. Similarly, from 232 individual drugs or combinations, the most prominent were dexamethasone (DEX; anti-inflammatory), paclitaxel (PTX; anticancer), fluoruracil (anticancer), ciprofloxacin (CFX) hydrochloride (antibiotic), and gentamicin (GS; antibiotic). A total of 51 manufacturing processes were encountered, of which the most reported were solvent evaporation, compression molding (CM), extrusion (EX), electrospinning (ELS), and melt molding (MM). Among 38 implant geometries, cylinder (CIL) was the most prominent, followed by disk, square film, circular film (FCIR), and undefined film. Release times varied greatly, although the majority of articles ranged between 5 and 300 d.

CONCLUSIONS

Drug-delivery implants were highly heterogeneous due to its applicability for multiple health conditions. Most implants were made of PLGA and most drugs assessed presented anti-inflammatory, antibiotic, or anticancer effects. Solvent evaporation and CIL were the most prominent manufacturing process and geometry, respectively.

Hydroxyapatite-Based Solution as Adjunct Treatment for Biofilm Management: An In Situ Study

Synthetic hydroxyapatite-based solution is a bioinspired material that may present anti-adhesive properties, restraining the dental biofilm formation without causing adverse effects. This in situ study aims to evaluate the effects of three different hydroxyapatite (HAP) watery solutions as a mouthwash against biofilm adhesion on different dental material surfaces under oral conditions. Hence, four volunteers carried maxillary splints containing enamel, titanium, ceramics, and polymethyl-methacrylate resin (PMMA) samples. Three HAP watery solutions (5%) were prepared with HAP particles presenting different shapes and sizes (HAP I, HAP II, HAP III). During 24 h, the volunteers rinsed two times with one of the following selected tested solution: HAP I, HAP II, HAP III, water, or chlorhexidine 0.2% (CHX). The first rinse was performed 3 min after pellicle formation; the second rinse occurred after a 12 h interval. The surface analysis was performed by scanning electron microscopy (SEM), fluorescence microscopy (FM), and transmission electron microscopy (TEM). Statistical and microscopic analysis showed that most samples treated with any HAP solution revealed reduced biofilm coverage presenting comparable results to CHX treated samples, however without altering the microorganisms' viability. In conclusion, the results of this investigation showed that a pure hydroxyapatite-based mouthrinse could be a promising bioinspired adjunct solution for biofilm management.

The Current Strategies in Controlling Oral Diseases by Herbal and Chemical Materials

Dental plaque is a biofilm composed of complex microbial communities. It is the main cause of major dental diseases such as caries and periodontal diseases. In a healthy state, there is a delicate balance between the dental biofilm and host tissues. Nevertheless, due to the oral cavity changes, this biofilm can become pathogenic. The pathogenic biofilm shifts the balance from demineralization-remineralization to demineralization and results in dental caries. Dentists should consider caries as a result of biological processes of dental plaque and seek treatments for the etiologic factors, not merely look for the treatment of the outcome caused by biofilm, i.e., dental caries. Caries prevention strategies can be classified into three groups based on the role and responsibility of the individuals doing them: (1) community-based strategy, (2) dental professionals-based strategy, and (3) individual-based strategy. The community-based methods include fluoridation of water, salt, and milk. The dental professionals-based methods include professional tooth cleaning and use of varnish, fluoride gel and foam, fissure sealant, and antimicrobial agents. The individual-based (self-care) methods include the use of fluoride toothpaste, fluoride supplements, fluoride mouthwashes, fluoride gels, chlorhexidine gels and mouthwashes, slow-release fluoride devices, oral hygiene, diet control, and noncariogenic sweeteners such as xylitol. This study aimed to study the research in the recent five years (2015–2020) to identify the characteristics of dental biofilm and its role in dental caries and explore the employed approaches to prevent the related infections.

Silver nanoparticles in endodontics: recent developments and applications

The elimination of endodontic biofilms and the maintenance of a leak-proof canal filling are key aspects of successful root canal treatment. Several materials have been introduced to treat endodontic disease, although treatment success is limited by the features of the biomaterials used. Silver nanoparticles (AgNPs) have been increasingly considered in dental applications, especially endodontics, due to their high antimicrobial activity. For the present study, an electronic search was conducted using MEDLINE (PubMed), the Cochrane Central Register of Controlled Trials (CENTRAL), Google Scholar, and EMBASE. This review provides insights into the unique characteristics of AgNPs, including their chemical, physical, and antimicrobial properties; limitations; and potential uses. Various studies involving different application methods of AgNPs were carefully examined. Based on previous clinical studies, the synthesis, means of obtaining, usage conditions, and potential cytotoxicity of AgNPs were evaluated. The findings indicate that AgNPs are effective antimicrobial agents for the elimination of endodontic biofilms.

Antibacterial Activity of Boswellia sacra Flueck. Oleoresin Extract against Porphyromonas gingivalis Periodontal Pathogen

Boswellia sacra Flueck. oleoresin extract (frankincense) has traditionally been used in the treatment of different diseases, but there are no sufficient studies on its potential activity against periodontal pathogens. Therefore, antibacterial and antibiofilm activity of frankincense extract against Porphyromonas gingivalis clinical isolates were studied. The phytochemical composition of the volatile components of the extract was identified by GC-MS analysis revealing 49 compounds as trans-nerolidyl formate, cycloartenol acetate, ursenoic acid 3-oxomethyl ester, bisabolene epoxide, and kaur-16-ene. It decreased the growth and increased the leakage of nucleotides in 58.3% and 33.3% of isolates, respectively. Additionally, it reduced the extracellular polysaccharide production and the cell surface hydrophobicity in 41.67% and 50% of the isolates, respectively. Crystal violet assay revealed inhibition of biofilm formation by the tested isolates. Light microscope and scanning electron microscope were used to examine the biofilms and they confirmed the reduction of biofilm formation by frankincense extract. Downregulation of the genes linked to biofilm formation (fimA, hagA, and hagB) was observed using qRT-PCR after treatment with the frankincense extract. This study suggested that the frankincense extract could exhibit antibacterial and antibiofilm activity against P. gingivalis isolates. Thus, the frankincense extract could be used as a treatment approach for periodontitis.

Role of bioglass in enamel remineralization: Existing strategies and future prospects-A narrative review

Enamel, once formed, loses the ability to regenerate due to the loss of the formative ameloblasts. It is subjected to constant damaging events due to exposure to external agents and oral microbiomes. An enamel remineralization process targets to replenish the lost ionic component of the enamel through a multitude of methods. Enamel remineralization is highly challenging as it has a complex organized hierarchical microstructure. Hydroxyapatite nanocrystals of the enamel vary in size and orientation along alignment planes inside the enamel rod. The inability of the enamel to remodel unlike other mineralized tissues is another substantial deterrent. One of the well-known biomaterials, bioglass (BG) induces apatite formation on the external surface of the enamel in the presence of saliva or other physiological fluids. Calcium, sodium, phosphate, and silicate ions in BG become responsive in the presence of body fluids, leading to the precipitation of calcium phosphate. Studies have also demonstrated the bactericidal potential of BG against Streptococcus mutans biofilms. The anticariogenicity and antibacterial activity were found to be enhanced when BG was doped with inorganic ions such as F, Ag, Mg, Sr, and Zn. Due to the versatility of BG, it has been combined with a variety of agents such as chitosan, triclosan, and amelogenin to biomimic remineralization process. Key strategies that can aid in the development of contemporary enamel remineralization agents are also included in this review.

Central Regulatory Role of Cytokines in Periodontitis and Targeting Options

BACKGROUND

Periodontitis is an immune-inflammatory disease that leads to the progressive destruction of bone and connective tissue in the periodontal area. The cytokine network plays a primary role in tissue homeostasis, the recruitment of immune cells to control the pathogenic impact and the regulation of osteoclastic function, thus modulating the intensity and duration of the immune response. This review provides an update on the main cytokines implicated in the pathogenesis and progression of periodontitis and their targeting potential in order to enrich current treatment options.

METHODS

A structured search of bibliographic databases (PubMed, MEDLINE, Scopus) was performed for peer-reviewed cytokine studies focused on periodontitis the last ten years. A qualitative content analysis was performed in screened papers and a critical discussion of main findings is provided.

RESULTS

An altered cytokine profile has been detected in periodontitis patients and the interplay of pro-inflammatory and/or anti-inflammatory cytokines has been associated with disease pathogenesis. Among the most prominent pro-inflammatory cytokines, TNF-α, IL-1β, IL-17, IL-6 and the chemokines CXCL-6, CXCL-8 are overexpressed in periodontitis patients and correlate with disease progression. On the other hand, the anti-inflammatory IL-4 and IL- 11 levels are reduced while IL-12 and IFN-γ expression play a dual role in periodontal disease. Current periodontitis treatment strategies include selective antibiotics, antimicrobial photodynamic therapy and probiotics, which can modulate the cytokine network and when applied in combination with specific anti-cytokine agents can exert additional beneficial effects.

CONCLUSION

It is evident that cytokines play a central regulatory role in the inflammatory process and immune cell response that underlies bone destruction in periodontitis. Specific cytokine targeting should be considered as a complementary therapeutic scheme to current periodontal management.

Synthesis of an urushiol derivative and its use for hydrolysis resistance in dentin adhesive

Hydrolysis resistance is essential to the durability of the dentin bonding interface. Urushiol is a natural monomer that has been used in different fields over thousands of years but has the disadvantage of a long drying time. In this study, we evaluated a novel photocurable derivative of urushiol as the main monomer for polymerization in dentin adhesive and its effect on hydrolysis resistance. The derivative was characterized by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance spectroscopy. Compared with the Adper Single Bond 2, the experimentally synthesized adhesives had higher contact angles. In particular, the water sorption/solubility of the experimental samples were significantly lower than that of Adper Single Bond 2. The microtensile bond strengths of the test groups were higher than that of the control group, even after 5000 thermocycles. Cytotoxicity test results showed that adhesives based on the original derivative induced low toxicity to L929 cells. The results of this study may shift the focus of future research to natural monomers and even their derivatives which may perform well in dentistry.

Overview of Antibacterial Strategies of Dental Implant Materials for the Prevention of Peri-Implantitis

As dental implants have become one of the main treatment options for patients with tooth loss, the number of patients with peri-implant diseases has increased. Similar to periodontal diseases, peri-implant diseases have been associated with dental plaque formation on implants. Unconventional approaches have been reported to remove plaque from infected implants, but none of these methods can completely and permanently solve the problem of bacterial invasion. Fortunately, the constant development of antibacterial implant materials is a promising solution to this situation. In this review, the development and study of different antibacterial strategies for dental implant materials for the prevention of peri-implantitis are summarized. We hope that by highlighting the advantages and limitations of these antimicrobial strategies, we can assist in the continued development of oral implant materials.

Interactions of dextransucrase purified from Streptococcus mutans 890 with plant polyphenols

Plant polyphenols have been extensively studied for their chemopreventive properties for human health. Dextransucrase plays an essential role in synthesizing exopolysaccharides from its exclusive substrate sucrose in Streptococcus mutans. In the present study, the effect of polyphenols gallic acid and tannic acid was investigated on the dextransucrase activity. The enzyme was purified by ethanol precipitation followed by column chromatography by Sephadex G-200 gel chromatography, followed by PEG-400 treatment. The purified enzyme exhibited 52 fold enrichment with 17.5% yield and specific activity of 3.54 Units/mg protein. On SDS-PAGE enzyme protein gave a single band with a molecular weight of 160 kDa. Dextransucrase activity was inhibited 80–90% by 0.04 mM tannic acid (TA) or 0.4 mM gallic acid (GA) suggesting that tannic acid has 10- fold more inhibitory potential than gallic acid on the activity of dextransucrase. CD/ORD studies revealed modifications in the tertiary structure of enzyme protein in presence of tannic acid and gallic acid, which were further confirmed by fluorescence spectra of the protein in presence of tannic acid. These results suggest that inhibition of dextransucrase activity in S. mutans by polyphenols may have potential applications in the prevention and control of dental caries.

i•

Dextransuccrase an important enzyme of S. mutans is involved in the metabolism of sucrose.

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Purified enzyme is inhibited (80-90%) by plant polyphenols. Observed inhibition is due to change in teritary structure.

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S. mutans is an important cariogenic agent.

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Plant polyphenols are good anticariogenic agents.