OBJECTIVE:To evaluate the efficacy of recombinant psoriasin as a novel treatment for oral candidiasis by eliminating Candida albicans growth on polymethyl methacrylate denture base. MATERIALS AND METHODS:Recombinant psoriasin protein was expressed and purified from E. coli, and Candida growth was monitored in vitro with varying concentrations of psoriasin. Subsequently, denture-base polymethyl methacrylate was immersed in psoriasin's solution or voriconazole, and fungal growth on the acrylic base and in the medium was examined by scanning electron microscopy and optical density, respectively. Cellular viability of HeLa and human gingival fibroblast cells treated with psoriasin was measured by methylene blue assay. RESULTS:The findings reveal an effective antifungal activity of psoriasin, completely inhibiting Candida albicans growth in RPMI at a protein concentration above 400 nM. Immersing the polymethyl methacrylate with 50 μM psoriasin completely eradicates fungal growth. Psoriasin has low cytotoxicity in HeLa cells at a concentration higher than 12 μM and no toxic effect on human gingival fibroblasts. CONCLUSIONS:This study marks psoriasin as an effective alternative to conventional antifungal treatments for denture stomatitis and a safe alternative to chemical antifungals in dental medicine and beyond.

Oral malodor still constitutes a major challenge worldwide. A strong effort is invested in eliminating volatile sulfur compound-producing oral bacteria through organic natural products such as essential oils. Fusobacterium nucleatum is a known volatile sulfur compound-producing bacteria that inspires oral malodor. The aim of the present study was to test the effect of lavender essential oil on the bacterium’s ability to produce volatile sulfide compounds, the principal components of oral malodor. Lavender (Lavandula angustifolia) essential oil was extracted by hydrodistillation and analyzed using GC-MS. The minimal inhibitory concentration (MIC) of lavender essential oil on Fusobacterium nucleatum was determined in a previous trial. Fusobacterium nucleatum was incubated anaerobically in the presence of sub-MIC, MIC, and above MIC concentrations of lavender essential oil, as well as saline and chlorhexidine as negative and positive controls, respectively. Following incubation, volatile sulfur compound levels were measured using GC (Oralchroma), and bacterial cell membrane damage was studied using fluorescence microscopy. Chemical analysis of lavender essential oil yielded five main components, with camphor being the most abundant, accounting for nearly one-third of the total lavender essential oil volume. The MIC (4 µL/mL) of lavender essential oil reduced volatile sulfur compound secretion at a statistically significant level compared to the control (saline). Furthermore, the level of volatile sulfur compound production attributed to 1 MIC of lavender essential oil was in the range of the positive control chlorhexidine with no significant difference. When examining bacterial membrane damage, 2 MIC of lavender essential oil (i.e., 8 µL/mL) demonstrated the same, showing antibacterial membrane damage values comparative to chlorhexidine. Since lavender essential oil was found to be highly effective in hindering volatile sulfur compound production by Fusobacterium nucleatum through the induction of bacterial cell membrane damage, the results suggest that lavender essential oil may be a suitable alternative to conventional chemical-based anti-malodor agents.

Oral candidiasis leading to denture stomatitis is a fungal infection resulting from unregulated growth and adhesion mainly of Candida albicans onto acrylic denture base. Once the biofilm is formed, it is immune resistant and mainstay treatments involve toxic chemical antifungal agents or mechanical cleaning techniques, both offer limited efficacy. Consequently, there is an urgent need for more effective and safer therapeutic approaches. While biological modalities are expanding in general medicine, the exploration of protein-based therapeutics in dental medicine remains limited. This research evaluates the inhibitory effect of recombinantly expressed psoriasin on the growth of Candida albicans on polymethyl methacrylate denture bases. Psoriasin, also known as S100-A7, has shown promise in treating microbial skin infections, and its natural presence in saliva makes it a promising candidate for treating oral microbial infections. Our findings indicate that psoriasin exhibits a strong, dose-dependent inhibition of Candida albicans growth. Further, we incubated a polymethyl methacrylate denture base within the psoriasin solution. Notably, immersing the denture base in the solution completely eradicated fungal growth. Our research utilizes natural antifungal proteins within biomedical devices like denture bases, suggesting psoriasin as a safe alternative to chemical antifungals in dental medicine. ### Competing Interest Statement M.G is a co-founder of Bountica Ltd. All other authors declare no conflict of interest.

A full-mouth radical dental treatment under general anesthesia is a common approach for treating severe early childhood caries (S-ECC). However, previous study showed recurrence of the disease in 80% of cases within 12 months. The aim of the present study was to examine the changes in microbial composition of the dental biofilm of these children following treatment. Dental biofilm samples from five children (mean age 45.4 ± 10.1 months) were taken before and three months after treatment and analyzed for microbial composition using Next Generation Sequencing of the microbial DNA extracted from these samples. Although some reductions in the abundance of caries-pathogenic bacteria (e.g., Streptococcus mutans, Streptococcus sobrinus, Rothia dentocariosa and Scardovia wiggisiae) were seen in the post-treatment follow up samples, these reductions were for the most part not statistically significant, and these bacteria remained well above detection levels. Taken together, the results of the present pilot study suggest that the dental treatment alone is not enough to reduce the caries risk status of these children and that a more comprehensive approach should be considered.

Previous study suggested that fixed dental prostheses (crowns) increase oral malodor production. There might be a role to temporary acrylic crowns contributing to oral malodor. In the current study, we analyzed the microbiome associated with malodorous temporary dental crowns. The study population comprised nineteen patients (mean age 45.8 ± 10.9, 8 females) who visited the Tel Aviv University dental clinic. Temporary crowns were scored by an odor judge using a 6-point malodor organoleptic scale (0–5) and temporary crowns that were scored 2 and above were assigned as malodor positive. Microbial DNA was extracted from the temporary dental crowns and analyzed using next generation 16S rDNA sequencing. Taxa identified could be classified into 11 phyla, 50 genera and 119 core species. Malodor positive samples demonstrated higher abundance of the phyla Proteobacteria and Actinobacteria and the genera Tannerella, Alloprevotella, Treponema, Olsenella and Bifidobacterium. Malodorous samples showed higher bacterial diversity and significant differences in microbial population. Taken together these results suggest a difference between the microbial populations of malodorous and non-malodorous temporary dental crowns both in composition and diversity.

Previous studies have shown that sub-lethal exposure of blue light caused increased bacterial cell membrane permeability. We hypothesized that combining blue light exposure with other antibacterial agents may increase their efficacy. The aim of the present study was to test the combined effect of blue light and sodium fluoride against dental caries pathogen Streptococcus mutans. Sm biofilms were exposed to blue light (400–500 nm) with or without sodium fluoride. Exposed and non-exposed samples were studied for acid production (lactate assay kit), acid tolerance (ATPase assay kit) and bacterial cell membrane damage (fluorescence microscopy). Results showed that the combined treatment significantly reduced the virulence of Sm concomitant with an increase in bacterial cell membrane permeability. Taken together, these results suggest that adjacent blue light exposure may increase fluoride caries preventive properties.

Streptococcus mutans is considered a major cariogenic bacterium. Most anti-cariogenic dentifrices are limited by a short exposure time. The aim of the present study was to test the hypothesis that adding a mucoadhesive agent to the formulation may increase its bioavailability and efficacy. We tested the effect of adding hydroxyethyl cellulose (HEC) to an herbal extract solution containing lavender, echinacea, sage, and mastic gum, which have been previously shown to be effective against Streptococcus mutans. Mucin-coated wells were treated with four test solutions: saline, herbal extracts, herbal extracts with HEC, and chlorhexidine. The wells were incubated with Streptococcus mutans and studied for biofilm formation (Crystal violet assay), acid production (lactate assay), acid tolerance (ATPase assay), and exopolysaccharide (EPS) production using fluorescent microscopy. The results showed that the addition of HEC to the herbal extract solution caused a significant reduction in Streptococcus mutans biofilm formation, lactic acid production, and EPS quantity (p < 0.001). These results suggest that HEC may be a beneficial added excipient to herbal extracts in an anti-cariogenic formulation.

Temporary dental crowns and bridges are commonly made of poly-methylmethacrylate (PMMA), a porous material attracting the microbial biofilm associated with malodor production. The purpose of the present study was to test pre-disinfection of PMMA on malodor-related parameters in an experimental oral biofilm. PMMA discs were pre-soaked in anti-malodor disinfecting solutions and controls: (i) Saline, (ii) essential oils (EO), (iii) herbal extracts (HE), and (iv) chlorhexidine (CHX). Following, discs were subjected to a salivary incubation assay and monitored for malodor-producing bacteria within the biofilm using confocal microscopy (CLSM), malodor production (organoleptic scale 0–5), volatile sulfide levels (Halimeter), and salivary protein degradation (SDS-PAGE). Results showed that disinfection solutions were significantly effective in reducing malodor-related parameters (CHX > HE > EO > Saline). Taken together, these results suggest that pre-disinfection may help to reduce malodor production in PMMA temporary dental restorations.

A previous study showed that sub-lethal exposure of blue light caused cell membrane damage in Fusobacterium nucleatum (Fn). The aim of the present study was to test the combined effect of blue light and silver nanoparticles against Fn. Bacterial suspensions were exposed to blue light (400–500 nm) with or without silver nanoparticles (10 nm). Exposed and non-exposed samples were studied for malodor production (Odor judge scores), VSC levels (Halimeter), reactive oxygen species (ROS) production (fluorimeter), and bacterial cell membrane damage (fluorescence microscopy). The results showed that combining blue light exposure and silver nanoparticles significantly reduced malodor and VSC production by Fn concomitant with increased ROS levels and bacterial cell membrane damage. These results suggest that silver nanoparticles may increase blue light phototoxicity against Fn.

Previously, we have shown that sublethal exposure of blue light caused increased cell membrane permeability inFusobacterium nucleatum. The aim of the present study was to test the effect of this exposure on the activity of Lavender, Sage, Echinacea and Mastic gum extracts against volatile sulfide compound (VSC) production byFusobacterium nucleatum. Bacterial suspensions were pre-exposed to blue light (400-500 nm) bellow minimal inhibitory dosage (sub-MID). Exposed and nonexposed samples were inoculated into test tubes containing growth medium, filtered saliva with or without herbal extracts. Following incubation, test tubes were tested for malodor production (odor judge scores), VSC levels (OralChroma), salivary protein degradation (SDS-PAGE) and bacterial cell membrane damage (fluorescence microscopy). Results showed that sub-MID blue light exposure significantly increased the ability of Lavender and Echinacea to reduce VSC production byFusobacterium nucleatumby more than 30%. These results suggest that sublethal blue light exposure may be useful to increase the efficacy of antimalodor agents.

Denture stomatitis is a common manifestation of oral candidiasis affecting some 65% of denture wearers. This condition is initiated by the adherence of Candida albicans to denture base acrylic resin. The present study aimed to test the in vitro effect of traditional and novel fabrication methods on Candida albicans adhesion to denture base samples. Denture based acrylic discs were fabricated using: (i) computerized milling, (ii) 3D printing, (iii) heat curing, and (iv) cold curing. Discs were tested for surface roughness (Ra), hydrophobicity (contact angle), mucin adsorption (Bradford assay), and Candida albicans adhesion. 3D printing significantly increased microbial cell adhesion as compared with heat curing, and computerized milling significantly decreased it. These results were associated with mucin adsorption levels rather than surface roughness. Results suggest that 3D printing may increase the risk for developing denture stomatitis, whereas computerized milling may decrease it as compared with traditional heat curing denture base fabrication.

Mucoadhesive tablets containing herbal formulation have been previously shown to reduce oral malodour. The aim of the present in vitro study was to test the effect of the mucoadhesive agent hydroxyethylcellulose (HEC) added to a liquid phase herbal extract formulation on the mucoadhesive retention of the active ingredients and their effect against malodour production. Experimental oral biofilms were grown on mucin coated glass slides treated with liquid phase solutions of herbal extract with or without HEC as well as saline and 0.2% chlorhexidine as controls. Biofilms were quantified for volatile sulfide compounds (VSC) producing bacteria using CLSM and sampled for a salivary incubation assay to test for malodour production (odour judge), VSC production (Halimeter) and salivary protein degradation (SDS-PAGE). Results showed that the addition of HEC to the herbal extracts solution has significantly increased its mucin retained activity against malodour producing bacteria and their resulting malodour and VSC production and proteolytic activities. Taken together, results of the present study suggest that the addition of HEC to a liquid phase herbal extract solution may increase its bioavailability time and efficacy. However, due to the limitations of this in vitro study additional clinical investigations are needed.

Oral malodour is considered to be caused mainly by the production of volatile sulfide compounds ( VSC ) by anaerobic gram‐negative oral bacteria. Previous studies showed that these bacteria were susceptible to blue light phototoxicity mediated by the production of reactive oxygen species ( ROS ). In the present study, we tested the effect of blue light on the integrity Fusobacterium nucleatum 's membrane, cellular proteins and DNA . Bacterial samples were exposed to high intensity blue light for 0, 70, 140 and 280 s ( i.e . fluences of 0, 96, 192 and 384 J cm −2 , respectively). Following light exposure, bacterial samples were examined for membrane damage using fluorescence microscopy, intra‐cellular protein analysis using electrophoresis ( SDS ‐ PAGE ) and DNA fragmentation using ultra–filtration. Results showed that the increasing exposure of bacterial samples to blue light caused increased membrane permeability concomitant with a reduction in intra‐cellular proteins and DNA fragments content. These results suggest that membrane damage is the main effect of high intensity blue light exposure on malodour producing bacteria.

Background A common reason for failure of root canal treatment is residual bacterial biofilm or reinfection due to coronal seal inadequacy. Recently, the idea of using macromolecules with antibacterial features has evolved. The addition of nanoparticle macromolecules to sealers gained antibiofilm properties as shown in several in vitro studies. Nevertheless, no technique has yet been able to completely eliminate the residual biofilm. We evaluated the in vitro antibacterial effect of epoxy sealer, BJM ROOT CANAL SEALER® (BJM Laboratories Ltd., Or-Yehuda, Israel), incorporated with non-nanoparticle quaternary ammonium macromolecule (BIOSAFE HM4100, Pittsburg, PA, USA) against existing biofilm of Enterococcus faecalis and its ability to inhibit it de-novo. Methods Six mm diameter discs of epoxy sealer (BJM) incorporated with various concentrations of immobilized ammonium particles (0, 0.4, 0.8, 1.6, and 3.3% w / v ) were tested for its antibacterial effect on de-novo biofilm formation (by Biofilm Formation assay), and on existing biofilm (by Biofilm Viability assay). The Live/Dead bacterial ratio was determined using fluorescence microscopy. Results Biofilm formation assay showed significant reductions in de-novo biofilm formation of 25 and 72% in the higher ammonium particle concentrations of 1.6 and 3.3% w / v respectively ( p < 0.001 for both). Biofilm viability assay showed significant reductions in existing biofilm viability of 20 and 36% in the higher ammonium particle concentrations of 1.6 and 3.3% w / v respectively ( p < 0.001 for both). Conclusions Biosafe incorporated in epoxy root canal sealer discs showed a pronounced reduction of de-novo biofilm formation in the higher concentrations (1.6 and 3.3% w / v ), as well as some antibacterial effect against existing biofilm of E . faecalis. This sealer may be effective for prevention of de-novo formation of bacterial biofilm in treated root canals.

The worldwide number of dental implants and orthopedic prostheses is steadily increasing. Orthopedic implant loosening, in the absence of infection, is mostly attributable to the generation of wear debris. Dental peri-implantitis is characterized by a multifactorial etiology and is the main cause of implant failure. It consists of a peri-implant inflammatory lesion that often results in loss of supporting bone. Disease management includes cleaning the surrounding flora by hand instruments, ultrasonic tips, lasers, or chemical agents. We recently published a paper indicating that US scaling of titanium (Ti) implants releases particles that provoke an inflammatory response and osteolysis. Here we show that a strong inflammatory response occurs; however, very few of the titanium particles are phagocytosed by the macrophages. We then measured a dramatic Ti particle-induced stimulation of IL1β, IL6, and TNFα secretion by these macrophages using multiplex immunoassay. The particle-induced expression profile, examined by FACS, also indicated an M1 macrophage polarization. To assess how the secreted cytokines contributed to the paracrine exacerbation of the inflammatory response and to osteoclastogenesis, we treated macrophage/preosteoclast cultures with neutralizing antibodies against IL1β, IL6, or TNFα. We found that anti-TNFα antibodies attenuated the overall expression of both the inflammatory cytokines and osteoclastogenesis. On the other hand, anti-IL1β antibodies affected osteoclastogenesis but not the paracrine expression of inflammatory cytokines, whereas anti-IL6 antibodies did the opposite. We then tested these neutralizing antibodies in vivo using our mouse calvarial model of Ti particle-induced osteolysis and microCT analysis. Here, all neutralizing antibodies, administered by intraperitoneal injection, completely abrogated the particle-induced osteolysis. This suggests that blockage of paracrine inflammatory stimulation and osteoclastogenesis are similarly effective in preventing bone resorption induced by Ti particles. Blocking both the inflammation and osteoclastogenesis by anti-TNFα antibodies, incorporated locally into a slow-release membrane, also significantly prevented osteolysis. The osteolytic inflammatory response, fueled by ultrasonic scaling of Ti implants, results from an inflammatory positive feedback loop and osteoclastogenic stimulation. Our findings suggest that blocking IL1β, IL6, and/or TNFα systemically or locally around titanium implants is a promising therapeutic approach for the clinical management of peri-implant bone loss.

In the past, our inability to cultivate most of the oral microorganisms has limited our view of this complex ecosystem. In the present study, we utilized next generation deep sequencing techniques to revisit the microbiome associated with denture malodour, a growing field with the rise in life expectancy. The study population comprised 26 full dentures patients (mean age 71 ± 6.4, 10 males, 16 females) who visited the Tel Aviv University dental geriatric clinic. Denture malodour was rated organoleptically by a single odour judge, and dentures scoring 2 and above were considered malodour positive. DNA was extracted from the swab samples and analysed using next generation deep sequencing 16 s rDNA technology. Taxa identified could be classified into nine phyla, 29 genera and 117 species. Malodour positive samples showed a higher abundance of the phyla Firmicutes and Fusobacteria and the genera Leptotrichia, Atopobium, Megasphaera, Oribacterium and Campylobacter. Microbiome analysis demonstrated higher bacterial diversity within the malodourous samples and a significant difference in the microbial profile within the two groups. Taken together these results suggest a difference between the microbial populations of malodourous and non-malodourous dentures both in composition and diversity.