Search Results (86)

Biofilm formation on denture base materials may contribute to oral diseases such as denture stomatitis and therefore represents an important factor in prosthodontic treatment. This in vitro study investigated biofilm formation on dental prosthetic materials manufactured by additive, subtractive, and conventional techniques. Disc-shaped specimens were fabricated from 3D-printed Denture Base Resin (Formlabs), milled Lucitone Digital Fit (Dentsply Sirona), and conventionally processed cold-polymerized PALAPress (Kulzer). Biofilm formation by Streptococcus mutans and Streptococcus sanguinis was assessed separately over a 21-day incubation period using crystal violet staining and photometric determination of optical density at eight predefined time points. Surface characteristics before and after microbial colonization were qualitatively evaluated by scanning electron microscopy. For S. mutans, significant material-dependent differences were observed only at selected time points, while overall biofilm accumulation remained low. In contrast, S. sanguinis exhibited pronounced and repeated differences, with milled PMMA generally showing lower biofilm accumulation compared with additively manufactured and conventionally processed materials. Overall, S. sanguinis formed significantly more biofilm than S. mutans across all materials and time points. These findings indicate that both manufacturing technique and bacterial species influence biofilm formation on denture base materials. Full article

Autoimmune gastritis (AIG) in its advanced atrophic stage is characterized by reduced acid secretion, dysbiosis, and gastric cancer (GC) risk. Swallowed oral bacteria surviving in increased intragastric pH may play a carcinogenic role. Oral microbiota was linked to increased GC risk. In AIG, the concomitant assessment of oral and gastric microbiota has not yet been performed. This study aimed to investigate the oral and gastric microbiota in AIG patients to clarify the role of oral bacteria in gastric dysbiosis. A case–control study on n = 20 histologically diagnosed AIG patients and n = 20 controls without AIG is conducted. Saliva samples were obtained from subjects who were fasting and without toothbrushing. Within 1 h, gastroscopy with biopsies (for histopathology and DNA extraction) was performed. Saliva (n = 40) and biopsy (n = 40) samples were frozen at −20 °C. DNA was extracted and prepared; paired-end sequencing was performed (IlluminaMiSeq-sequencer, San Diego, CA, USA). Bacterial abundance in biopsies was higher in AIG than in controls (p = 0.06), but was not different in the saliva (p = 0.54) samples. In biopsies, AIG showed a lower Shannon-Index than controls (p = 0.001). In saliva studies, AIG showed a higher Shannon-Index than controls (p = 0.0). In biopsies, Streptococcus oralis, Fusobacterium pseudoperiodonticum, Veillonella rogosae, and Gemella sanguinis were more frequent in AIG (p < 0.03). The most abundantly shared taxa between saliva and biopsy were S. oralis and Prevotella histicola; Gemella sanguinis, Fusobacterium pseudoperidonticum, and Veillonella rogosae were shared in AIG patients only. This study confirmed gastric dysbiosis in AIG. Oral taxa were more commonly associated with AIG and shared between the mouth and the stomach. In AIG, the oral microbiota is associated with gastric dysbiosis, highlighting the importance of oral eubiosis in patients with impaired gastric acid secretion. Full article

Streptococcus sanguinis (S. sanguinis) is an oral commensal and early colonizer of the tooth surface that contributes to dental biofilm homeostasis. Zinc oxide nanoparticles (ZnO NPs) are often incorporated into dental restorative materials to enhance mechanical performance and confer antibacterial properties; however, their effects on S. sanguinis have not been thoroughly studied. Here, we investigated the antimicrobial and antibiofilm efficacy of ZnO NPs against this bacterial species. ZnO NPs exhibited a minimal inhibitory concentration (MIC) of 100 µg/mL and caused rapid, dose-dependent suppression of intracellular ATP levels and overall metabolic activity within 2–4 h of exposure. ZnO NPs induced reactive oxygen species (ROS) production in a dose-dependent manner. The free radical scavenger α-tocopherol partly prevented the antibacterial effect of ZnO NPs, suggesting that lipid peroxidation contributes to ZnO NP-mediated toxicity, although it is not the sole mechanism involved. Short-term exposure (2 h) to ZnO NPs did not significantly affect membrane integrity or cellular morphology, whereas prolonged treatment (24 h) resulted in pronounced membrane permeabilization, membrane hyperpolarization, and cellular swelling. Computational morphometric analyses of high-resolution scanning electron microscopy (HR-SEM) images of planktonic growing bacteria after a 24 h treatment confirmed a significant, dose-dependent increase in cell surface area and surface roughness. Importantly, ZnO NPs also reduced the metabolic activity and compromised the structural integrity of mature, preformed biofilms. Collectively, these findings demonstrate that ZnO NPs exert antimicrobial and antibiofilm effects against S. sanguinis through early metabolic inhibition associated with oxidative stress followed by progressive membrane dysfunction. Full article

Zn-based ternary deep eutectic solvents (TDESs) have attracted significant attention due to their good biodegradability, stability, and sustainability. In this work, TDESs composed of choline chloride:urea (ChCl:U) and zinc salts, ZnCl₂, Zn(CH₃COO)₂, and ZnSO₄ were synthesized and characterized by Fourier transform infrared (FTIR) spectroscopy and laser desorption ionization mass spectrometry (LDI MS). Their antibacterial activity against cariogenic Streptococcus species isolates was determined by microdilution assay, while their cytotoxic potential and effect on the intracellular reactive oxygen species (ROS) induction were analyzed on the MRC-5 fibroblast cell line by XTT, trypan blue, and DCF assays, respectively. FTIR confirmed that hydrogen bonds prevail in the molecular structure of ChCl:U:Zn salts, while LDI MS revealed the interactions between zinc salts and ChCl:U. The antibacterial TDES potential was high, especially against Streptococcus sanguinis, with ChCl:U:ZnCl₂ displaying the most promising effects (MICs 1.13–18.12 µg/mL). Cytotoxicity assessment showed that concentrations up to 100 µg/mL of all TDESs did not display significant cytotoxicity, while higher concentrations significantly reduced cell viability by increasing ROS production and cell membrane damage, outlining the safety window of up to 100 µg/mL. Strong antibacterial activity of low TDESs concentrations combined with their good biocompatibility highlights their potential as innovative candidates for biomedical application. Full article

Microbial colonization is a major factor contributing to peri-implantitis, and creating durable glassy surfaces with antimicrobial agents such as silver and copper may reduce microbial accumulation on dental abutments. This study aimed to develop antimicrobial thin-film glassy surfaces on Ti6Al4V alloy and to evaluate their surface and mechanical properties, antimicrobial effectiveness, and biocompatibility before and after thermal aging. A sol–gel-derived glassy matrix (G) was synthesized, and two antimicrobial coatings were prepared by incorporating ionic Ag (GAg) or a combination of Ag/Cu (GAgCu). Ti6Al4V specimens; these were either left uncoated or dip-coated with G, GAg, or GAgCu and cured at 450 °C. Half of the specimens underwent thermal aging between 5 °C and 55 °C for 3000 cycles. Surface roughness, contact angle, hardness, adhesion strength, scratch resistance, cytotoxicity (Agar diffusion and MTT assay on L929 fibroblasts), and microbial adhesion were evaluated using Streptococcus sanguinis, Porphyromonas gingivalis, and Candida albicans as representative oral microorganisms. Both coatings exhibited low surface roughness, hydrophilic surfaces, improved hardness, and significantly reduced microbial adhesion for all tested species. GAg showed superior mechanical properties, whereas GAgCu demonstrated a relatively stronger antimicrobial effect. Cytotoxicity tests indicated that all coatings were biocompatible at levels suitable for oral use. Overall, these coatings demonstrated strong adhesion, durability, and antimicrobial activity, suggesting their suitability for dental abutments made of Ti6Al4V. Full article

Oral diseases such as dental caries, stomatitis, and periodontitis are closely associated with biofilms that are resistant to conventional therapeutic approaches. Streptococcus sanguinis and Streptococcus mutans play a key role as primary and secondary colonizers of oral surfaces, respectively, and interact synergistically with other species, including Candida albicans, to promote the establishment and progression of infection. Objective: To evaluate the antimicrobial activity of ethanolic extracts of propolis from Tame (Arauca) on biofilms formed in co-cultures from reference strains and co-cultures with clinical isolates of oral pathogens. Methodology: Propolis was collected from Apis mellifera hives placed in rural Tame (Arauca), located in the foothills of the Eastern Andes (Colombia). Ethanolic extracts of propolis (EEP) were prepared in a 0.07 g/mL concentration and biological characterization was performed on single and complex co-cultures of S. mutans (serotype c), S. sanguinis, and C. albicans using disc diffusion test, determination of MIC and BMC, growth curves and biofilm formation. The cell viability and metabolic activity of primary cell cultures derived from a dental pulp explant were evaluated using the MTT assay. Results: EEP exhibited higher inhibition zones than chlorhexidine against S. mutans and C. albicans and lower efficacy against S. sanguinis. Among the microorganisms evaluated, S. mutans showed the lowest MIC and BCM values, followed by C. albicans and S. sanguinis. Growth curves and biofilm formation assays revealed higher inhibition in co-cultures of reference strains (S. mutans + C. albicans), while multi-species cultures (S. mutans + S. sanguinis + C. albicans), or clinical strains (S. mutans clinical isolated + S. sanguinis + C. albicans), showed higher resistance. Cell viability assays revealed low cytotoxicity (<30%) in primary cell cultures. Conclusions: EEPs exhibited antimicrobial activity against relevant oral pathogens, especially in simple co-cultures, supporting their potential as natural therapeutic alternatives. However, their efficacy decreases in the presence of clinical strains and complex co-cultures, highlighting the importance of considering these variables in the development of oral treatments. Full article

Background/Objectives: Dental caries and candidiasis are major health problems worldwide. Dental caries is caused by cariogenic bacteria, especially those belonging to the Streptococcus genus, whereas candidiasis is caused by Candida species. In this study, the antimicrobial activity of a series of synthetic N-methyl-4-piperidone-derived monoketone curcuminoids (MKCs) against Candida albicans, C. krusei, and a representative panel of cariogenic bacteria was assessed. Methods: Fifteen MKCs were synthesized using an environmentally friendly base-catalyzed Claisen–Schmidt condensation between an aromatic aldehyde (R-PhCHO) and N-methyl-4-piperidone ethanol using NaOH as the catalyst. These compounds were evaluated for their antibacterial activity against a representative panel of cariogenic bacteria, along with their antifungal activity against Candida krusei and C. albicans. The antimicrobial activity was determined based on the Minimum Inhibitory Concentration (MIC) values. Results: Most of the compounds were obtained in about 2 h in yields ranging from 40 to 70%. None of the compounds displayed antifungal activity, even at 100 μg/mL, the highest tested concentration. Similarly, none of the compounds were active against Enterococcus faecalis. On the other hand, compounds 1 (R = H), 10 (R = 3,4,5-OMe), and 13 (R = 3-F) displayed moderate activity against Streptococcus mutans (13), S. salivarus (1), L. paracasei (1 and 10), S. mitis (1, 10, and 13), S. sanguinis (1, 10, and 13), and S. sobrinus (13), with MIC values of 250 μg/mL and 500 μg/mL. The presence of the N-methyl-4-piperidone ring was found to boost the antibacterial activity as compared to the corresponding acetone-derived MKCs. Moreover, the antibacterial activity of compounds 10 and 13 was associated with the presence and position of the fluor atom and the methoxy groups at the aromatic ring. Conclusions: This study contributed to a better understanding of the antimicrobial activity of MKCs, whose data in the literature are still scarce. Full article

The objective of this study was an assessment of the anti-biofilm properties of fluoride non-thermal atmospheric plasma (FNTAP) generated using argon and hydrocarbon fluoride gas 1,1,1,2-tetrafluoroethane (TFE). These properties were evaluated by measuring the destruction and recovery of in vitro dual-species biofilms of Streptococcus mutans and Streptococcus sanguinis exposed to FNTAP at 5 or 10 standard cubic centimeters per minute (sccm) or argon non-thermal atmospheric plasma (ArNTAP) for 1 or 2 min, using resazurin-based reagent viability assays, colony forming units (CFU), culture media pH and live/dead staining. Both ArNTAP and FNTAP resulted in significant immediate reductions in bacterial load as compared to the control. Although ArNTAP did not significantly reduce biofilm regrowth, FNTAP treatment showed a bacterial load reduction of more than 5 log units of biofilm regrowth. FNTAP treatments significantly reduced the acidification of the culture medium after recovery incubation, indicating reduced living bacteria, with a pH of 6.92 ± 0.02 and 6.90 ± 0.03, respectively, for the 5 sccm and 10 sccm FNTAP treatments, as compared to a pH of 5.83 ± 0.26 for the ArNTAP treatment, and a significantly acidic pH of 4.76 ± 0.04 for the no-treatment groups. Our results suggest that FNTAP has exceptional anti-biofilm effects, and future directions of our research include the assessment of potential applications of FNTAP in clinical settings. Full article

The distribution of oral pathogens is influenced by genetic background, diet, socioeconomic status, and racial factors. This study aimed to assess the distribution and characteristics of oral pathogens based on blood glucose levels in a South Korean population. This cross-sectional, retrospective study included subjects from 17 health promotion centers in 13 South Korean cities between November 2021 and December 2022. Real-time multiplex PCR was used to detect 10 periodontitis-related pathogens, 6 dental caries-related pathogens, and 1 dental caries-protective bacterium. The most prevalent periodontitis-related pathogens were Parvimonas micra (97.6%), Porphyromonas endodontalis (96.8%), and Treponema socranskii (95.0%). Among dental caries-related pathogens, Streptococcus sanguinis and Veillonella parvula were found in all subjects. The prevalence of periodontitis-related pathogens was higher in males, while pathogens related to periodontitis and dental caries were more prevalent in older individuals. In the diabetes group, Aggregatibacter actinomycetemcomitans, red and orange complexes, and Streptococcus mutans were more prevalent. The relative amount of S. sanguinis was lower, while V. parvula was higher in individuals with diabetes mellitus. The prevalence and composition of oral pathogens vary by sex, age, and blood glucose levels. Diabetic individuals showed a pathogenic community structure linked to increased risks of periodontitis and dental caries. Full article

The microbiome plays a crucial role in cancer development, influencing fundamental processes such as cell proliferation, apoptosis, immune system regulation, and host metabolism. Recent studies have highlighted a possible relationship between esophageal cancer and the oral microbiota, making oral microflora a possible risk factor. The bacteria Prevotella intermedia, Tannerella forsythia, Streptococcus sanguinis, and Streptococcus mutans, implicated in various oral pathologies, were of interest in this study, which was initiated to examine their potential role in the etiology of esophageal squamous cell carcinoma (ESCC). To achieve this, a case-control design was used, with whole saliva samples collected from 24 healthy controls and 24 patients with esophageal squamous cell carcinoma. DNA was then extracted, and real-time PCR was performed to quantify the presence of the targeted bacteria in both groups. The results showed that all the bacteria studied were present in the saliva of both patients with ESCC and healthy controls. However, expression levels were significantly higher in patients with ESCC. Specifically, a marked increase in the presence of P. intermedia, T. forsythia, S. sanguinis, and S. mutans was observed in the patients with cancer compared to the healthy controls. In short, this study highlights a significant imbalance in the microbial flora, with an increased abundance of selected bacteria in patients with ESCC. The monitoring of these bacteria could thus be exploited to track patients who are at risk. Their integration into diagnostic and therapeutic strategies would offer new prospects for the early diagnosis and improved prognosis of patients at risk of ESCC. Full article

Agricultural food waste and by-products could provide high-value compounds that positively affect human and environmental health, thus representing promising ingredients for cosmeceutical products. This study explores the biological activities of tomato skin (HP) and pomegranate peel (PPE) extracts on oral mucosa to evaluate their possible use in mouthwashes. The biological activities of the extracts and the mouthwash (MW) containing them were evaluated in Human Primary Gingival Epithelial cells (HGECs). The antioxidant and anti-inflammatory activities were analyzed in HGECs injured with lipopolysaccharides. After 24 h of treatment with PPE, HP, and MW, significant antioxidant activity and an increased Superoxide Dismutase 1 expression (p < 0.01) were observed. Additionally, the extracts significantly reduced the expression of tumor necrosis factor α (p < 0.05) and Monocyte Chemoattractant Protein 1 (p < 0.001), suggesting an anti-inflammatory role. Lastly, the antibacterial activity was assessed against Streptococcus mutans and Streptococcus sanguinis by the broth microdilution method and agar cup diffusion test for the extracts and the mouthwash, respectively, demonstrating strong effectiveness against both oral streptococcus species. Results demonstrate the potential of HP and PPE in reducing oxidative stress, inflammation, and bacterial proliferation within oral mucosa, highlighting food waste up-cycling as a resource for human health. Full article

Background: Streptococcus sanguinis is a leading cause of infective endocarditis (IE), which causes diverse clinical symptoms and even death. Recurrence after treatment is a crucial problem in IE, possibly caused by the presence of “persister” cells, a small bacterial population that can survive antimicrobials. In this study, the residual risk for penicillin G (PCG) and gentamicin (GM), used for treating IE, to induce Streptococcus sanguinis persisters, was investigated. Methods: The bactericidal effects of PCG and GM on S. sanguinis were evaluated. Furthermore, we confirmed whether the S. sanguinis that survived following combination treatment with PCG and GM were persisters. The bactericidal effect of the combination of PCG and GM against S. sanguinis was measured after the addition of glucose or arginine. Results: Following 48 h of treatment with PCG (1600 μg/mL) and GM (64 μg/mL), S. sanguinis survived, albeit with a low bacterial count, indicating the presence of persisters. The addition of glucose or arginine to PCG and GM increased the bactericidal effect on residual persister cells and reduced the number of persister cells. Moreover, the addition of glucose at concentrations of 10 mg/mL or higher was substantially effective in achieving sterilization. Conclusions: Our findings demonstrate that persisters of S. sanguinis that survive antimicrobial treatment may make the treatment of IE challenging, and that combining antimicrobial treatment with glucose is effective for eliminating persisters of S. sanguinis. Taken together, these findings may facilitate the development of novel therapeutic strategies against IE caused by oral streptococcal infection. Full article

Objectives: The aim of this study is to investigate the antimicrobial efficacy of antimicrobial photodynamic therapy (PDT) using natural photosensitizers (curcumin, riboflavin, and phycocyanin) and light-emitting diode (LED) irradiation against multispecies biofilms in an acrylic denture base model. Materials and Methods: Forty-five acrylic specimens were fabricated using heat-curing acrylic resin. The specimens were then infected with a mixed culture of bacterial and fungal species (including Streptococcus mutans, Streptococcus sanguinis, Candida albicans, and Candida glabrata) for 4 days. The acrylic discs were divided into nine groups, with each group containing five discs: control, 0.2% chlorhexidine, 5.25% sodium hypochlorite, curcumin, riboflavin, phycocyanin alone or along with LED. After treatment, the number of colony-forming units (CFUs) per milliliter was counted. In addition, the extent of biofilm degradation was assessed using the crystal violet staining method and scanning electron microscopy. Results: All experimental groups exhibited a significant reduction in colony numbers for both bacterial and fungal species compared to the control (p < 0.001). The PDT groups exhibited a statistically significant reduction in colony counts for both bacteria and fungi compared to the photosensitizer-only groups. Conclusions: The results of this in vitro study show that PDT with natural photosensitizers and LED devices can effectively reduce the viability and eradicate the biofilm of microorganisms responsible for causing denture infections. Full article

Implantoplasty is one of the most common techniques to remove peri-implantitis from the surface of dental implants. It is a process of mechanization of the titanium surface, causing the loss of the roughness of the dental implant, which leads to difficulty in tissue regeneration. The aim of this research is to apply a decontaminant based on citric acid and add collagen and magnesium cations to promote tissue formation and have a bactericidal character. Eighty commercially pure grade 3 titanium discs were used to perform the implantoplasty protocol, like the one used in dental clinics. They were treated with four different solutions: 25% citric acid, 25% citric acid with the addition of collagen 0.25 g/L, 25% citric acid with the addition of 0.50 g/L and the latter with the addition of 1% Mg (NO₃)₂. The roughness was determined by confocal microscopy, the contact angle, adhesion and proliferation of HFFs fibroblasts, proliferation of SaOS-2 osteoblasts and bactericidal behavior by culturing very common bacteria in the oral cavity, Gram-positive Streptococcus sanguinis and gordonii and as Gram-negative Pseudomonas aeruginosa. The results showed that the treatment with citric acid slightly increases the roughness and decreases the contact angle from 78 to 13°, making the surface superhydrophilic. Fibroblast proliferation studies show a very significant increase at 24 h, the most favorable solution being the one containing 0.50 g/L of collagen with the presence of magnesium in a 25% citric acid solution. This same solution shows the highest cytocompatibility and osteoblastic proliferation with statistically significant differences with respect to the control and the rest of the solutions. Microbiological studies show a bactericidal effect due to the presence of citric acid, which is especially effective on Gram-positive bacteria. The results allow us to have mouthwashes that can be applied in the patient’s mouth, which will help the regeneration of tissues and avoid new bacterial colonization. Full article

Artepillin C, drupanin, and plicatin B are prenylated phenylpropanoids that naturally occur in Brazilian green propolis. In this study, these compounds and eleven of their derivatives were synthesized and evaluated for their in vitro antimicrobial activity against a representative panel of oral bacteria in terms of their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Plicatin B (2) and its hydrogenated derivative 8 (2′,3′,7,8-tetrahydro-plicatin B) were the most active compounds. Plicatin B (2) displayed strong activity against all the bacteria tested, with an MIC of 31.2 μg/mL against Streptococcus mutans, S. sanguinis, and S. mitis. On the other hand, compound 8 displayed strong activity against S. mutans, S. salivarius, S. sobrinus, Lactobacillus paracasei (MIC = 62.5 μg/mL), and S. mitis (MIC = 31.2 μg/mL), as well as moderate activity against Enterococcus faecalis and S. sanguinis (MIC = 125 μg/mL). Compounds 2 and 8 displayed bactericidal effects (MBC: MIC ≤ 4) against all the tested bacteria. In silico studies showed that the complexes formed by compounds 2 and 8 with the S. mitis, S. sanguinis, and S. mutans targets (3LE0, 4N82, and 3AIC, respectively) had energy score values similar to those of the native S. mitis, S. sanguinis, and S. mutans ligands due to the formation of strong hydrogen bonds. Moreover, all the estimated physicochemical parameters satisfied the drug-likeness criteria without violating the Lipinski, Veber, and Egan rules, so these compounds are not expected to cause problems with oral bioavailability and pharmacokinetics. Compounds 2 and 8 also had suitable ADMET parameters, as the online server pkCSM calculates. These results make compounds 2 and 8 good candidates as antibacterial agents against oral bacteria. Full article