Silver diamine fluoride in preventing enamel erosion: An in vitro study with salivary pellicle.

OBJECTIVES: To compare the prevention of enamel erosion and discolouring effect with a single and two weekly topical applications of silver diamine fluoride (SDF) solution. METHODS: Human enamel blocks were divided into four groups. Group 1 (SDF2) received two weekly applications of SDF solution (Advantage Arrest: 260,000 ppm Ag, 44,300 ppm F, pH 9.1). Group 2 (SDF1) received a single application of SDF solution. Group 3 (SNF, Positive Control) received daily application of stannous-chloride/amine-fluoride/sodium-fluoride solution (Elmex® Enamel professional: 800 ppm Sn(II), 500 ppm F, pH 4.5). Group 4 (DW, Negative Control) received daily application of deionised water. The treated blocks were subjected to a 14-day erosive challenge. Crystal characteristics, elemental composition, surface morphology, percentage of surface microhardness loss (%SMHL), surface loss, and total colour change (ΔE) of the blocks were investigated using X-ray diffraction (XRD), energy-dispersive spectrometry (EDS) and scanning electron microscopy (SEM), Vickers' hardness testing, non-contact profilometry, and digital spectrophotometry, respectively. RESULTS: XRD and EDS revealed precipitates of silver for SDF2 and SDF1 and tin for SNF. SEM showed prominent etched enamel pattern on DW than the other three groups. The%SMHL (%) of SDF2, SDF1, SNF, and DW were 26.6 ± 2.9, 33.6 ± 2.8, 38.9 ± 2.9, and 50.5 ± 2.8 (SDF2SDF1=SNF>DW, p < 0.05). CONCLUSION: Two weekly applications was more effective than a single application of SDF in preventing enamel erosion, though it caused more discolouration. CLINICAL SIGNIFICANCE: Topical application of 38 % SDF with two weekly applications protocol is effective in preventing enamel erosion.

Unveiling the "hidden quality" of the walnut pellicle: a precious source of bioactive lipids.

Tree nut consumption has been widely associated with various health benefits, with walnuts, in particular, being linked with improved cardiovascular and neurological health. These benefits have been attributed to walnuts' vast array of phenolic antioxidants and abundant polyunsaturated fatty acids. However, recent studies have revealed unexpected clinical outcomes related to walnut consumption, which cannot be explained simply with the aforementioned molecular hallmarks. With the goal of discovering potential molecular sources of these unexplained clinical outcomes, an exploratory untargeted metabolomics analysis of the isolated walnut pellicle was conducted. This analysis revealed a myriad of unusual lipids, including oxylipins and endocannabinoids. These lipid classes, which are likely present in the pellicle to enhance the seeds' defenses due to their antimicrobial properties, also have known potent bioactivities as mammalian signaling molecules and homeostatic regulators. Given the potential value of this tissue for human health, with respect to its "bioactive" lipid fraction, we sought to quantify the amounts of these compounds in pellicle-enriched waste by-products of mechanized walnut processing in California. An impressive repertoire of these compounds was revealed in these matrices, and in notably significant concentrations. This discovery establishes these low-value agriculture wastes promising candidates for valorization and translation into high-value, health-promoting products; as these molecules represent a potential explanation for the unexpected clinical outcomes of walnut consumption. This "hidden quality" of the walnut pellicle may encourage further consumption of walnuts, and walnut industries may benefit from a revaluation of abundant pellicle-enriched waste streams, leading to increased sustainability and profitability through waste upcycling.

Influence of bottled salad dressings on the development of enamel erosion in the presence or absence of salivary pellicle - An in vitro study.

Background: Acidic beverages are believed to elevate the risk of enamel surface erosion. In addition to the intake of soft drinks, the increased consumption of salad dressings has been linked to a higher prevalence of dental erosion. Therefore, the current study aimed to investigate the influence of bottled salad dressings on the development of enamel erosion in the presence or absence of pellicle through in vitro experiment. Methods: Preliminary pH and calcium analyses of solutions were performed. Highest pH and calcium content was found for sandwich spread i.e., 4.69 and 55.4 mg/100 g grams, respectively. Eighty tooth specimens (measuring 4 × 4 × 3 mm) were prepared from extracted human premolars and randomly assigned to four groups (group 1: orange juice; group 2: eggless plain mayonnaise; group 3: sandwich spread; and group 4: thousand island dressing) with 20 samples in each group. Ten tooth specimens from each group were immersed in 20 ml of the respective solutions for 5 min (control group). The remaining ten tooth specimens from each group were submerged in 5 mL saliva vials for 3 min to facilitate salivary pellicle formation before being immersed in their respective solutions for 5 min (saliva-covered group). Pre and post-experimental assessments of enamel roughness and hardness were conducted using a surface roughness tester and Knoop Hardness indenter, respectively. Results: Overall, enamel roughness was notably elevated in the control group, with the eggless plain mayonnaise (0.52 ± 0.38) and thousand island dressing groups (0.57 ± 0.29) showing a significant increase in surface roughness post-test (p = 0.05). Nevertheless, there was no significant difference in the enamel roughness between the groups. On the other hand, regardless of the presence/absence of the salivary pellicle, a marked decrease in enamel hardness was observed among all groups except for group 3 (sandwich spread) with a mean score of 311.5 ± 82.6 (p < 0.05). Conclusion: A significant increase in surface roughness and reduction in enamel hardness was observed with salad dressings. However, in vitro formed salivary pellicle showed a protective effect against tooth erosion.

Construction of knockout mutants in Mycobacterium intracellulare ATCC13950 strain using a thermosensitive plasmid containing negative selection marker rpsL.

BACKGROUND: Nontuberculous mycobacterial disease has emerged worldwide over the past 20 years. However, there are currently few reports on the established technique for constructing knockout mutants of nontuberculous mycobacteria. Therefore, gene recombination techniques for nontuberculous mycobacteria require further research. RESULTS: We constructed vector pPR23LHR that harbors the ribosomal protein S12 gene (rpsL+) as a dominant negative selection marker and the hygromycin (Hyg) and lacZ cassettes as positive selection markers. We constructed knockout mutants of proteasomal genes, which we found to be required for hypoxic pellicle formation in Mycobacterium intracellulare by functional genomic analysis. The knockout mutants showed impaired hypoxic pellicle formation, consistent with previous data using epoxomicin, a proteasomal inhibitor. CONCLUSIONS: Our findings demonstrate that rpsL+ is an efficient dominant negative selection marker for gene recombination in nontuberculous mycobacteria. Our temperature-sensitive rpsL+ method for the construction of knockout mutants will facilitate functional assays to validate the virulence factors of nontuberculous mycobacteria and the pathogenesis of nontuberculous mycobacterial disease.

A novel cost-effective methodology for the screening of nanocellulose producing micro-organisms.

In this paper, the work has been done to develop a cost-effective methodology, for the isolation of the potential producer of bacterial nanocellulose. No report is available in the literature, on the use of gram flour and table sugar for the screening of nanocellulose-producing isolates. Since commercially used, Hestrin-Schramm medium is expensive for the isolation of nanocellulose-producing micro-organisms, the possibility of using gram flour-table sugar medium was investigated in this work. Qualitative screening of micro-organisms was done using cost-effective medium, i.e., gram flour-table sugar medium. Qualitative analysis of various nanocellulose-producing bacteria depicted that cellulose layer production occurred on both HS medium and gram flour-table sugar medium. The yield of nanocellulose was also better on air-liquid surface in case of gram flour-table sugar medium as compared to HS medium. 16S rRNA was used for molecular characterization of bacterial strain and the best nanocellulose producer was identified as Novacetimonas hansenii BMK-3_NC240423 (isolated from rotten banana). FTIR and FE-SEM studies of nanocellulose pellicle produced on HS medium and gram flour-table sugar medium demonstrated equivalent structural, morphological, and chemical properties. The cost of newly designed medium (0.01967 $/L) is nearly 90 times lower than the Hestrin-Schramm medium (1.748 $/L), which makes the screening of nanocellulose producers very cost-effective. A strategy of using gram flour extract-table sugar medium for the screening of nanocellulose-producing micro-organisms is a novel approach, which will drastically reduce the screening associated cost of cellulose-producing micro-organisms and also motivate the researchers/industries for comprehensive screening programme for getting high cellulose-producing microbes.

In vivo modification of the enamel pellicle and saliva resveratrol levels after use of resveratrol-containing orodispersible capsules.

OBJECTIVES: To evaluate in vivo 1) the bioavailability of trans-resveratrol when administered through sublingual capsules; 2) the effect of resveratrol on the protein composition of the acquired enamel pellicle (AEP). DESIGN: Ten volunteers received a sublingual capsule containing 50 mg of trans-resveratrol. Unstimulated saliva was then collected after 0, 30, 60, and 120 min and AEP was collected after 120 min following administration of the capsule. In the next week, the volunteers received a placebo sublingual capsule, and saliva and AEP were collected again. Saliva samples were analyzed for free trans-resveratrol using high-performance liquid chromatopgraphy (HPLC), and AEP samples were subjected to proteomic analysis (nLC-ESI-MS/MS). RESULTS: Trans-resveratrol was detected in saliva at all the time points evaluated, with the peak at 30 min. A total of 242 proteins were identified in both groups. Ninety-six proteins were increased and 23 proteins were decreased in the Resveratrol group. Among the up-regulated proteins, isoforms of cystatins, PRPs, Mucin-7, Histatin-1, Lactotrasnferrin and Lysozyme-C were increased and the isoforms of Protein S100, Neutrophil defensins, Albumin, PRPs, and, Statherin were decreased in Resveratrol group. CONCLUSION: The sublingual capsule is effective at increasing the bioavailability of trans-resveratrol in saliva. Several proteins involved in important processes to maintain systemic and oral health homeostasis were identified. These proteins differently expressed due to the presence of trans-resveratrol deserve attention for future studies, since they have important functions, mainly related to antimicrobial action.

Impact of microorganisms on key processes of organic acid metabolism during the occurrence and disappearance of paocai pellicle.

In vegetable fermentation, pellicle is a common quality deterioration phenomenon. This study investigates the characteristics of glucose, organic acids, amino acids, and biogenic amines during the pellicle occurrence and disappearance of paocai. The results revealed a slight increase in pH of the fermentation system after pellicle occurred, and glucose was the main carbohydrate that microbial activity primary relied on. The microorganisms responsible for pellicle formation consumed organic acids in brine, but the lactic acid in paocai gradually increased and exceeded 25 mg/g. The appearance of pellicle caused a decrease in total free amino acids from 200.390 mg/100 g to 172.079 when pellicle occurred, whereas its impact on biogenic amines was not apparent. Through Kyoto Encyclopedia of Genes and Genomes pathway enrichment of metagenomics sequencing data, screening, and sorting of the key enzymes involved in organic acid metabolism, it was observed that the composition and species of the key microorganisms capable of metabolizing organic acids were more abundant before the appearance of pellicle. When pellicle occurred, lactic acid may be metabolized by Lactobacillus plantarum; in contrast, Lactobacillus and Pichia were associated with citric acid metabolism, and Lactobacillus, Pichia, Saccharomycodes, and Kazachstania were linked to malic acid metabolism. Moreover, Prevotella, Kazachstania, Lactobacillus, Vibrio, and Siphonobacter were implicated in succinic acid metabolism. Additionally, the production of tartaric acid and oxalic acid in paocai and brine resulted from abiotic effects. This knowledge offers a theoretical basis for precise control of paocai fermentation process. PRACTICAL APPLICATION: Our study revealed the specific situation of the metabolites produced by the microorganisms during the pollution and recovery process of pellicle in paocai fermentation, especially the effect of pellicle on the key process of organic acid metabolism. These research results provided theoretical basis for precise control of paocai fermentation.

The Contribution of Scanning Force Microscopy on Dental Research: A Narrative Review.

Scanning force microscopy (SFM) is one of the most widely used techniques in biomaterials research. In addition to imaging the materials of interest, SFM enables the mapping of mechanical properties and biological responses with sub-nanometer resolution and piconewton sensitivity. This review aims to give an overview of using the scanning force microscope (SFM) for investigations on dental materials. In particular, SFM-derived methods such as force-distance curves (scanning force spectroscopy), lateral force spectroscopy, and applications of the FluidFM® will be presented. In addition to the properties of dental materials, this paper reports the development of the pellicle by the interaction of biopolymers such as proteins and polysaccharides, as well as the interaction of bacteria with dental materials.

Erosion protective properties of the enamel pellicle in-situ.

OBJECTIVES: Previous studies on short- and long-term pellicles showed that the enamel pellicle provides partial protection against erosion. The aim of the present study was to investigate the protective properties of clinically relevant pellicles formed within 2 to 24 h. The hypothesis was that factors such as pellicle formation time, intraoral location, and acidic challenge severity would not influence the erosion-protective properties of the pellicle. METHODS: Six subjects participated in the study. Bovine enamel specimens were prepared and intraorally exposed at buccal or palatal sites for 2, 6, 12, and 24 h to allow pellicle formation, followed by erosion using 0.1 % or 1 % citric acid. Calcium release and surface microhardness were measured, and specimens were analysed using scanning and transmission electron microscopy. Quantitative data were statistically analysed with three-way ANOVA and Tuckey's multiple comparison test (p = 0.05). RESULTS: Pellicle formation time and intraoral location did not significantly influence the erosion-protective properties of the pellicle, while citric acid concentration significantly affected enamel erosion. The pellicle thickness increased with longer formation times and on buccal sites, but decreased or was entirely removed following treatment with 0.1 % or 1 % citric acid, respectively. The enamel surface exhibited a characteristic erosion pattern. CONCLUSIONS: This study underscores the importance of investigating pellicle properties within the critical 2- to 24-h timeframe and highlights the significance of pellicle thickness in acid resistance. CLINICAL SIGNIFICANCE: These findings provide valuable insights into the factors influencing the protective properties of enamel pellicles and could guide preventive measures in dental practice.

Acquired enamel pellicle and biofilm engineering with a combination of acid-resistant proteins (CaneCPI-5, StN15, and Hemoglobin) for enhanced protection against dental caries - in vivo and in vitro investigations.

OBJECTIVE: This study was designed in two-legs. In the in vivo, we explored the potential of a rinse solution containing a combination (Comb) of 0.1 mg/mL CaneCPI-5 (sugarcane-derive cystatin), 1.88 × 10- 5M StN15 (statherin-derived peptide) and 1.0 mg/mL hemoglobin (Hb) to change the protein profile of the acquired enamel pellicle(AEP) and the microbiome of the enamel biofilm. The in vitro, was designed to reveal the effects of Comb on the viability and bacterial composition of the microcosm biofilm, as well as on enamel demineralization. MATERIALS AND METHODS: In vivo study, 10 participants rinsed (10mL,1 min) with either deionized water (H2O-control) or Comb. AEP and biofilm were collected after 2 and 3 h, respectively, after rinsing. AEP samples underwent proteomics analysis, while biofilm microbiome was assessed via 16 S-rRNA Next Generation Sequencing(NGS). In vitro study, a microcosm biofilm protocol was employed. Ninety-six enamel specimens were treated with: 1)Phosphate-Buffered Solution-PBS(negative-control), 2)0.12%Chlorhexidine, 3)500ppmNaF and 4)Comb. Resazurin, colony-forming-units(CFU) and Transversal Microradiography(TMR) were performed. RESULTS: The proteomic results revealed higher quantity of proteins in the Comb compared to control associated with immune system response and oral microbial adhesion. Microbiome showed a significant increase in bacteria linked to a healthy microbiota, in the Comb group. In the in vitro study, Comb group was only efficient in reducing mineral-loss and lesion-depth compared to the PBS. CONCLUSIONS: The AEP modification altered the subsequent layers, affecting the initial process of bacterial adhesion of pathogenic and commensal bacteria, as well as enamel demineralization. CLINICAL RELEVANCE: Comb group shows promise in shaping oral health by potentially introducing innovative approaches to prevent enamel demineralization and deter tooth decay.

Biofouling on titanium implants: a novel formulation of poloxamer and peroxide for in situ removal of pellicle and multi-species oral biofilm.

Eradicating biofouling from implant surfaces is essential in treating peri-implant infections, as it directly addresses the microbial source for infection and inflammation around dental implants. This controlled laboratory study examines the effectiveness of the four commercially available debridement solutions '(EDTA (Prefgel®), NaOCl (Perisolv®), H2O2 (Sigma-Aldrich) and Chlorhexidine (GUM® Paroex®))' in removing the acquired pellicle, preventing pellicle re-formation and removing of a multi-species oral biofilm growing on a titanium implant surface, and compare the results with the effect of a novel formulation of a peroxide-activated 'Poloxamer gel (Nubone® Clean)'. Evaluation of pellicle removal and re-formation was conducted using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy to assess the surface morphology, elemental composition and chemical surface composition. Hydrophilicity was assessed through contact angle measurements. The multi-species biofilm model included Streptococcus oralis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans, reflecting the natural oral microbiome's complexity. Biofilm biomass was quantified using safranin staining, biofilm viability was evaluated using confocal laser scanning microscopy, and SEM was used for morphological analyses of the biofilm. Results indicated that while no single agent completely eradicated the biofilm, the 'Poloxamer gel' activated with 'H2O2' exhibited promising results. It minimized re-contamination of the pellicle by significantly lowering the contact angle, indicating enhanced hydrophilicity. This combination also showed a notable reduction in carbon contaminants, suggesting the effective removal of organic residues from the titanium surface, in addition to effectively reducing viable bacterial counts. In conclusion, the 'Poloxamer gel + H2O2' combination emerged as a promising chemical decontamination strategy for peri-implant diseases. It underlines the importance of tailoring treatment methods to the unique microbial challenges in peri-implant diseases and the necessity of combining chemical decontaminating strategies with established mechanical cleaning procedures for optimal management of peri-implant diseases.

Acquired Pellicle and Biofilm Engineering by Rinsing with Hemoglobin Solution.

INTRODUCTION: The identification of acid-resistant proteins, including hemoglobin (Hb), within the acquired enamel pellicle (AEP) led to the proposition of the "acquired pellicle engineering" concept, which involves the modification of the AEP by incorporating specific proteins, presenting a novel strategy to prevent dental demineralization. OBJECTIVE: Combining in vivo and in vitro proof-of-concept protocols, we sought to reveal the impact of AEP engineering with Hb protein on the biofilm microbiome and enamel demineralization. METHODS: In the in vivo studies, 10 volunteers, in 2 independent experiments, rinsed (10 mL,1 min) with deionized water-negative control or 1.0 mg/mL Hb. The AEP and biofilm formed along 2 or 3 h, respectively, were collected. AEP was analyzed by quantitative shotgun-label-free proteomics and biofilm by 16S-rRNA next-generation sequencing (NGS). In in vitro study, a microcosm biofilm protocol was employed. Seventy-two bovine enamel specimens were treated with (1) phosphate-buffered solution (PBS), (2) 0.12% chlorhexidine, (3) 500 ppm NaF, (4) 1.0 mg/mL Hb, (5) 2.0 mg/mL Hb, and (6) 4.0 mg/mL Hb. The biofilm was cultivated for 5 days. Resazurin, colony forming units (CFU), and transversal microradiography were performed. RESULTS: Proteomics and NGS analysis revealed that Hb increased proteins with antioxidant, antimicrobial, acid-resistance, hydroxyapatite-affinity, calcium-binding properties and showed a reduction in oral pathogenic bacteria. In vitro experiments demonstrated that the lowest Hb concentration was the most effective in reducing bacterial activity, CFU, and enamel demineralization compared to PBS. CONCLUSION: These findings suggest that Hb could be incorporated into anticaries dental products to modify the oral microbiome and control caries, highlighting its potential for AEP and biofilm microbiome engineering.

Impact of pH-adjusted fluoride and stannous solutions on the protective properties on the pellicle layer in vitro and in situ.

This study evaluates the ideal pH for anti-erosion and anti-adherent efficacy of fluoride and stannous solutions (sodium fluoride (SF), amine fluoride (AF), sodium monofluorophosphate (SMFP), stannous fluoride (SnF2) with 500 ppm fluoride concentration each and stannous chloride (SnCl2, 1563 ppm stannous)). In vitro, solutions were tested at pH 4.5 and 5.5. The main in situ experiments were carried out at the pH of 4.5: For pellicle formation 6 volunteers wore bovine enamel slabs intraorally for 1 min, rinsed with 8 ml solution for 1 min and continued for up to 30 min/8 h. Physiological pellicle samples served as controls. After incubation in HCl (2.0, 2.3) for 2 min mineral release was determined photometrically. Bacterial counts on 8 h biofilms were determined by fluorescence microscopy (BacLight™ and DAPI with Concanavalin A). Modification of the pellicle ultrastructure was examined by TEM. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney-U tests with Bonferroni-correction (p < 0.05). SnF2 showed a significant erosion protection. AF, SnF2, and SnCl2 were most anti-adherent. SnF2 and SnCl2 caused a pronounced basal pellicle with stannous precipitates. Compared to other fluoride monosubstances, stannous ions offer greater protection against erosive acidic attacks. Stannous ions act as crucial co-factor in this process.

Increase in plasma resveratrol levels and in acid-resistant proteins in the acquired enamel pellicle after use of resveratrol-containing orodispersible tablets.

OBJECTIVE: This study evaluated the effect of administration of trans-resveratrol-containing orodispersible tablets on the protein composition of the AEP and on blood plasma trans-resveratrol concentrations. METHODS: Ten volunteers participated in two crossover double-blind phases. In each phase, after dental prophylaxis, they received a trans-resveratrol (15 mg) orodispersible tablet, or a placebo tablet (without actives). The AEP formed after 120 min was collected with electrode filter papers soaked in 3 % citric acid. Blood samples were collected 30, 45, 60 and 120 min after the use of the tablet. After protein extraction, AEP samples were analyzed by shotgun labelfree quantitative proteomics and plasma samples were analyzed by high-performance liquid chromatography (HPLC). RESULTS: Eight hundred and two proteins were identified in the AEP. Among them, 336 and 213 were unique to the trans-resveratrol and control groups, respectively, while 253 were common to both groups. Proteins with important functions in the AEP had increased expression in the trans-resveratroltreated group, such as neutrophil defensins, S100 protein isoforms, lysozyme C, cystatin-D, mucin-7, alphaamylase, albumin, haptoglobin and statherin. Trans-resveratrol was detected in the plasma at all the times evaluated, with the peak at 30 min. CONCLUSIONS: The administration of trans-resveratrol in sublingual orodispersible tablets was effective both to increase the bioavailability of the polyphenol and the expression of antibacterial and acid-resistant proteins in the AEP, which might benefit oral and general health.

Hemoglobin Protects Enamel against Intrinsic Enamel Erosive Demineralization.

INTRODUCTION: This study investigated the changes in the acquired enamel pellicle (AEP) proteome when this integument is formed in vivo after treatment with sugarcane-derived cystatin (CaneCPI-5), hemoglobin (HB), and a statherin-derived peptide (StN15), or their combination and then exposed to an intrinsic acid challenge. The effectiveness of these treatments in preventing intrinsic erosion was also evaluated. METHODS: Ten volunteers, after prophylaxis, in 5 crossover phases, rinsed with the following solutions (10 mL, 1 min): control (deionized water-H2O) - group 1, 0.1 mg/mL CaneCPI-5 - group 2, 1.0 mg/mL HB - group 3, 1.88 × 10-5M StN15 - group 4, or a blend of these - group 5. Following this, AEP formation occurred (2 h) and an enamel biopsy (10 µL, 0.01 m HCl, pH 2.0, 10 s) was conducted on one incisor. The biopsy acid was then analyzed for calcium (Arsenazo method). The vestibular surfaces of the other teeth were treated with the same acid. Acid-resistant proteins in the residual AEP were then collected and analyzed quantitatively via proteomics. RESULTS: Compared to control, treatment with the proteins/peptide, mixed or isolated, markedly enhanced acid-resistant proteins in the AEP. Notable increases occurred in pyruvate kinase PKM (11-fold, CaneCPI-5), immunoglobulins and submaxillary gland androgen-regulated protein 3B (4-fold, StN15), Hb, and lysozyme C (2-fold, StN15). Additionally, a range of proteins not commonly identified in the AEP but known to bind calcium or other proteins were identified in groups treated with the tested proteins/peptide either in isolation or as a mixture. The mean (SD, mM) calcium concentrations released from enamel were 3.67 ± 1.48a, 3.11 ± 0.72a, 1.94 ± 0.57b, 2.37 ± 0.90a, and 2.38 ± 0.45a for groups 1-5, respectively (RM-ANOVA/Tukey, p < 0.05). CONCLUSIONS: Our findings demonstrate that all treatments, whether using a combination of proteins/peptides or in isolation, enhanced acid-resistant proteins in the AEP. However, only HB showed effectiveness in protecting against intrinsic erosive demineralization. These results pave the way for innovative preventive methods against intrinsic erosion, using "acquired pellicle engineering" techniques.

Effect of Polyphenols on the Ultrastructure of the Dentin Pellicle and Subsequent Erosion.

INTRODUCTION: Erosive tooth wear is a highly prevalent dental condition that is modified by the ever-present salivary pellicle. The aim of the present in situ study was to investigate the effect of polyphenols on the ultrastructure of the pellicle formed on dentin in situ and a subsequent erosive challenge. METHODS: The pellicle was formed on bovine dentin specimens for 3 min or 2 h in 3 subjects. After subjects rinsed with sterile water (negative control), 1% tannic acid, 1% hop extract, or tin/fluoride solution containing 800 ppm tin and 500 ppm fluoride (positive control), specimens were removed from the oral cavity. The erosive challenge was performed on half of the specimens with 1% citric acid, and all specimens were analyzed by transmission electron microscopy. Incorporation of tannic acid in the pellicle was investigated by fluorescence spectroscopy. RESULTS: Compared to the negative control, ultrastructural analyses reveal a thicker and electron-denser pellicle after application of polyphenols, in which, according to spectroscopy, tannic acid is also incorporated. Application of citric acid resulted in demineralization of dentin, but to a lesser degree when the pellicle was pretreated with a tin/fluoride solution. The pellicle was more acid-resistant than the negative control when modified with polyphenols or tin/fluoride solution. CONCLUSION: Polyphenols can have a substantial impact on the ultrastructure and acid resistance of the dentin pellicle, while the tin/fluoride solution showed explicit protection against erosive demineralization.

Development of New Models of Oral Mucosa to Investigate the Impact of the Structure of Transmembrane Mucin-1 on the Mucosal Pellicle Formation and Its Physicochemical Properties.

The mucosal pellicle (MP) is a biological film protecting the oral mucosa. It is composed of bounded salivary proteins and transmembrane mucin MUC1 expressed by oral epithelial cells. Previous research indicates that MUC1 expression enhances the binding of the main salivary protein forming the MP, MUC5B. This study investigated the influence of MUC1 structure on MP formation. A TR146 cell line, which does not express MUC1 natively, was stably transfected with genes coding for three MUC1 isoforms differing in the structure of the two main extracellular domains: the VNTR domain, exhibiting a variable number of tandem repeats, and the SEA domain, maintaining the two bound subunits of MUC1. Semi-quantification of MUC1 using dot blot chemiluminescence showed comparable expression levels in all transfected cell lines. Semi-quantification of MUC5B by immunostaining after incubation with saliva revealed that MUC1 expression significantly increased MUC5B adsorption. Neither the VNTR domain nor the SEA domain was influenced MUC5B anchoring, suggesting the key role of the MUC1 N-terminal domain. AFM-IR nanospectroscopy revealed discernible shifts indicative of changes in the chemical properties at the cell surface due to the expression of the MUC1 isoform. Furthermore, the observed chemical shifts suggest the involvement of hydrophobic effects in the interaction between MUC1 and salivary proteins.

Superior rat wound-healing activity of green synthesized silver nanoparticles from acetonitrile extract of Juglans regia L: Pellicle and leaves.

The process of wound healing is complicated. Antimicrobial silver has been one of the substances used for wounds since ancient times. Moreover, traditional medicine has long used Juglans regia L. to promote wound healing. Since eco-friendly nanotechnology has various uses in biomedical research, the aim of this study was to assess the wound-healing capacity of bio-reduced silver nanoparticles (AgNPs). UV, DLS, TEM, and FTIR were used to characterize the prepared AgNPs. Pellicle's bioreduced AgNP (AgNP/P) has a better polydispersity index (PI) of 0.336 compared to its chemically synthesized peers, which have a PI of 0.67. Using incision and excision wound healing models, AgNPs and extracts were compared to Solcoseryl®. Skin-breaking strength, wound contraction, epithelialization time, histology, and cytokines were all assessed. Juglans regia L. pellicle extract (P) has shown significant effectiveness in both models, as well as their bio-reduced partner AgNP/P. The skin's tensile strength following AgNP/P therapy (871 g, p value < 0.05) is comparable to that after Solcoseryl® (928 g), both of which are significantly better than AgNP (592 g) in the incision wound model. Epithelialization time (16.0 and 16.5 days) did not substantially differ from Solcoseryl® (15.3 days) (P value < 0.05). There was an elevated collagen content. Low levels of IL1ß (189.0 pg/g) and high levels of TNF-α (1007.1 pg/g) in the case of AgNP/P suggest various cellular kinds of maturation and various wound healing structures that are evident in histopathology investigations. The bioreduced AgNP/P could find use as a pharmaceutical agent for wound healing dressings.

A new role for resveratrol: Protection of enamel against erosion.

OBJECTIVE: The aim of this study was to determine the effect of different concentrations of resveratrol in protecting enamel against initial dental erosion in vitro. METHODS: Ninety bovine enamel samples (4 × 4 mm) were divided into six groups: Phosphate buffered saline (negative control; PBS), Commercial solution (Elmex Erosion Protection™; positive control) and resveratrol at 4 different concentrations (1, 10, 100 or 400 µg/mL). Initially, the samples were incubated in saliva for the formation of the acquired pellicle (250 µL, 1 h, 37 °C, 250 rpm). Afterward, the samples were incubated in the respective treatments (250 µL, 1 min, 37 °C, 250 rpm) and then reincubated in saliva (250 µL, 1 h, 37 °C, 250 rpm). Finally, the samples were subjected to an erosive challenge by incubating in 1 % citric acid (1 mL, pH 3.5, 1 min, 25 °C, 250 rpm). The percentage surface microhardness change (% SMC) was assessed using a microhardness tester. Data were analyzed by Kruskal-Wallis and Dunn's tests (p < 0.05). RESULTS: The treatments with Elmex™ and resveratrol (1, 10 and 100 µg/mL) significantly protected enamel compared to the negative control, without significant differences among them. However, the group treated with the highest resveratrol concentration (400 µg/mL) did not show a significant difference from the negative control. CONCLUSIONS: Resveratrol at concentrations ranging from 1 to 100 µg/ml was effective in preventing loss of enamel surface microhardness. CLINICAL SIGNIFICANCE: This result suggests a potential new direction for the development of dental products based on resveratrol for the prevention of dental erosion.

Can the combination of proanthocyanidin and vitamin E or palm oil effectively protect enamel against in vitro erosive and abrasive challenges?

Abstract Objectives This study aimed to assess the effect of proanthocyanidin, palm oil and vitamin E against erosive and erosive+abrasive challenges in vitro after enamel pellicle formation in situ. Methodology Bovine enamel blocks (n=84) were obtained and divided into the following treatment groups: negative control (NC) - deionized water; positive control (PC) - SnCl2/NaF/AmF-containing solution; palm oil (PO); 2% proanthocyanidin (P2); vitamin E (VitE); 2% proanthocyanidin+palm oil (P2PO); and 2% proanthocyanidin+vitamin E (P2VitE). For 5 days, one half of the sample from each group was subjected to erosion and the other half was subjected to erosion+abrasion. The acquired enamel pellicle (AEP) was pre-formed in situ for 30 minutes. The specimens were then treated in vitro with solutions (500 µl, 30s for each group). Subsequently, the blocks were left in the oral cavity for another hour to obtain the modified AEP. The blocks were immersed in 0.5% citric acid (pH=2.5) for 90s, 4×/day. AEP formation and treatment were carried out before the first and third erosive challenges, and after these challenges, abrasive cycles (15s) were performed on half of the samples. Enamel wear was quantified by profilometry and data were analyzed by two-way ANOVA and Tukey's test (p<0.05). Results All groups showed higher wear when exposed to erosion+abrasion than when exposed to erosion alone (p=0.0001). PO, P2VitE, P2, and P2PO showed enamel wear similar to the PC group, but only PC, PO and P2VitE differed from the NC group. The other groups behaved similarly to NC. Conclusion It was concluded that the combination of proanthocyanidin and vitamin E was effective in reducing wear in the face of in vitro erosive and erosive+abrasive challenges.