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Abstract The objective of this in vitro study was to assess the efficacy of CaneCPI-5, either alone or in combination with various concentrations of sodium trimetaphosphate (TMP) in protecting against initial enamel erosion. A total of 135 bovine enamel specimens were prepared and categorized into nine groups (n/group=15) according to the following treatments: Deionized water; Commercial solution (Elmex Erosion ProtectionTM); 0.1 mg/mL CaneCPI-5; 0.5% TMP; 1.0% TMP; 3.0% TMP; 0.1 mg/mL CaneCPI-5+0.5% TMP; 0.1 mg/mL CaneCPI-5+1.0%TMP; and 0.1 mg/mL CaneCPI-5+3.0%TMP. The specimens were treated with the respective solutions for 2 h, followed by acquired enamel pellicle formation for 2 h and exposure to 0.65% citric acid (CA) for 1 min. These procedures were repeated once a day for three consecutive days. Demineralization was assessed by the percentage change in surface hardness (%CSH) and calcium release into CA, analyzed by the Arsenazo III method. The data were evaluated using Kruskal-Wallis/Dunn's tests. Regarding %CSH, CaneCPI-5+3.0%TMP was the most effective treatment when compared to the CaneCPI-5 group alone. As for calcium release into CA, the CaneCPI-5+0.5% TMP and CaneCPI-5 groups (both with lower calcium release) did not significantly differ from the commercial solution. In conclusion, combination of CaneCPI-5 with TMP enhances the protective potential against initial enamel erosion in vitro.

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

The objective of this in vitro study was to assess the efficacy of CaneCPI-5, either alone or in combination with various concentrations of sodium trimetaphosphate (TMP) in protecting against initial enamel erosion. A total of 135 bovine enamel specimens were prepared and categorized into nine groups (n/group=15) according to the following treatments: Deionized water; Commercial solution (Elmex Erosion ProtectionTM); 0.1 mg/mL CaneCPI-5; 0.5% TMP; 1.0% TMP; 3.0% TMP; 0.1 mg/mL CaneCPI-5+0.5% TMP; 0.1 mg/mL CaneCPI-5+1.0%TMP; and 0.1 mg/mL CaneCPI-5+3.0%TMP. The specimens were treated with the respective solutions for 2 h, followed by acquired enamel pellicle formation for 2 h and exposure to 0.65% citric acid (CA) for 1 min. These procedures were repeated once a day for three consecutive days. Demineralization was assessed by the percentage change in surface hardness (%CSH) and calcium release into CA, analyzed by the Arsenazo III method. The data were evaluated using Kruskal-Wallis/Dunn's tests. Regarding %CSH, CaneCPI-5+3.0%TMP was the most effective treatment when compared to the CaneCPI-5 group alone. As for calcium release into CA, the CaneCPI-5+0.5% TMP and CaneCPI-5 groups (both with lower calcium release) did not significantly differ from the commercial solution. In conclusion, combination of CaneCPI-5 with TMP enhances the protective potential against initial enamel erosion in vitro. [ABSTRACT FROM AUTHOR]

(1) Background: In the oral environment, sound enamel and dental restorative materials are immediately covered by a pellicle layer, which enables bacteria to attach. For the development of new materials with repellent surface functions, information on the formation and maturation of salivary pellicles is crucial. Therefore, the present in situ study aimed to investigate the proteomic profile of salivary pellicles formed on different dental composites. (2) Methods: Light-cured composite and bovine enamel samples (controls) were exposed to the oral cavity for 30, 90, and 120 min. All samples were subjected to optical and mechanical profilometry, as well as SEM surface evaluation. Acquired pellicles and unstimulated whole saliva samples were analyzed by SELDI–TOF–MS. The significance was determined by the generalized estimation equation and the post-hoc bonferroni adjustment. (3) Results: SEM revealed the formation of homogeneous pellicles on all test and control surfaces. Profilometry showed that composite surfaces tend to be of higher roughness compared to enamel. SELDI–TOF–MS detected up to 102 different proteins in the saliva samples and up to 46 proteins in the pellicle. Significant differences among 14 pellicle proteins were found between the composite materials and the controls. (4) Conclusions: Pellicle formation was material- and time-dependent. Proteins differed among the composites and to the control. [ABSTRACT FROM AUTHOR]

BackgroundThe dental pellicle is a thin layer of up to several hundred nm in thickness, covering the tooth surface. It is known to protect the teeth from acid attacks through its selective permeability and it is involved in the remineralization process of the teeth. It functions also as binding site and source of nutrients for bacteria and conditioning biofilm (foundation) for dental plaque formation.MethodsFor this updated literature review, the PubMed database was searched for the dental pellicle and its composition.ResultsThe dental pellicle has been analyzed in the past years with various state-of-the art analytic techniques such as high-resolution microscopic techniques (e.g., scanning electron microscopy, atomic force microscopy), spectrophotometry, mass spectrometry, affinity chromatography, enzyme-linked immunosorbent assays (ELISA), and blotting-techniques (e.g., western blot). It consists of several different amino acids, proteins, and proteolytic protein fragments. Some studies also investigated other compounds of the pellicle, mainly fatty acids, and carbohydrates.ConclusionsThe dental pellicle is composed mainly of different proteins, but also fatty acids, and carbohydrates. Analysis with state-of-the-art analytical techniques have uncovered mainly acidic proline-rich proteins, amylase, cystatin, immunoglobulins, lysozyme, and mucins as main proteins of the dental pellicle. The pellicle has protective properties for the teeth. Further research is necessary to gain more knowledge about the role of the pellicle in the tooth remineralization process.

Abstract The objective of this study was to compare the protein profile of the acquired enamel pellicle (AEP) formed in vivo in patients with or without gastroesophageal reflux disease (GERD), and with or without erosive tooth wear (ETW). Twenty-four volunteers were divided into 3 groups: 1) GERD and ETW; 2) GERD without ETW; and 3) control (without GERD). The AEP formed 120 min after prophylaxis was collected from the lingual/palatal surfaces. The samples were subjected to mass spectrometry (nLC-ESI-MS/MS) and label-free quantification by Protein Lynx Global Service software. A total of 213 proteins were identified, or 119, 92 and 106 from each group, respectively. Group 2 showed a high number of phosphorylated and calcium-binding proteins. Twenty-three proteins were found in all the groups, including 14-3-3 protein zeta/delta and 1-phosphatidylinositol. Several intracellular proteins that join saliva after the exfoliation of oral mucosa cells might have the potential to bind hydroxyapatite, or participate in forming supramolecular aggregates that bind to precursor proteins in the AEP. Proteins might play a central role in protecting the dental surface against acid dissolution.

Abstract Polyphenols interact with salivary proteins and thus can improve the pellicle’s erosion protective properties. This effect could be exploited to create rinsing solutions with polyphenols as active ingredients for erosion prevention. Different from the current gold standard for erosion protective rinsing solutions, these rinses would not rely on stannous ions. This would offer alternatives for patients with concerns regarding the composition of rinsing solutions and preferring bio-products. Objective To develop an erosion-preventive rinsing solution containing natural polyphenol-rich extracts. Methodology Solutions were prepared with polyphenols from either grapeseed extract or cranberry extract, 500 ppm fluoride added, and additionally flavors and sweeteners. Controls were deionized water, 500 ppm fluoride solution, and the gold standard rinse in the field (Sn2+/F-). In total, 135 enamel specimens (n=15/group) were subjected to five cycles of salivary pellicle formation (30 min, 37°C), modification with the solutions (2 min, 25°C), further salivary pellicle formation (60 min, 37°C), and erosive challenge (1 min, 1% citric acid, pH 3.6). Relative surface microhardness (rSMH), surface reflection intensity (rSRI), and amount of calcium release (CaR) were investigated. Data were analyzed with Kruskal-Wallis and Wilcoxon rank sum tests (α=0.05). Results The polyphenol solutions containing fluoride, as well as additional flavors, protected enamel better than fluoride alone, and similar to the Sn2+/F- solution, when investigating both rSMH and CaR. When measuring rSRI, Sn2+/F- showed the best protection, while the polyphenol solutions were similar to fluoride. Conclusion For two of the three assessed parameters (rSMH and CaR), both developed polyphenol-rich rinsing solutions were able to protect enamel from erosion, improving/potentializing the effect of fluoride and matching the protection offered by the current gold standard rinsing solution.

The objective of this study was to compare the protein profile of the acquired enamel pellicle (AEP) formed in vivo in patients with or without gastroesophageal reflux disease (GERD), and with or without erosive tooth wear (ETW). Twenty-four volunteers were divided into 3 groups: 1) GERD and ETW; 2) GERD without ETW; and 3) control (without GERD). The AEP formed 120 min after prophylaxis was collected from the lingual/palatal surfaces. The samples were subjected to mass spectrometry (nLC-ESI-MS/MS) and label-free quantification by Protein Lynx Global Service software. A total of 213 proteins were identified, or 119, 92 and 106 from each group, respectively. Group 2 showed a high number of phosphorylated and calciumbinding proteins. Twenty-three proteins were found in all the groups, including 14-3-3 protein zeta/delta and 1-phosphatidylinositol. Several intracellular proteins that join saliva after the exfoliation of oral mucosa cells might have the potential to bind hydroxyapatite, or participate in forming supramolecular aggregates that bind to precursor proteins in the AEP. Proteins might play a central role in protecting the dental surface against acid dissolution. [ABSTRACT FROM AUTHOR]

Introduction and Aims: With the increasing prevalence of dentin hypersensitivity, more and more desensitizing agents with tubule-occluding properties are advocated in the market. The aim of the present study was to investigate the deposition of these agents on the dentin surface under in-situ conditions., Methods: Bovine dentin specimens were pretreated with phosphoric acid and fixed to individual upper splints that were carried by up to 2 subjects for 3 min to allow pellicle formation. The desensitizing agents containing either calcium carbonate and arginine, casein-phosphopeptide amorphous calcium phosphate, zinc-carbonate hydroxyapatite, tetracalcium phosphate and dicalcium phosphate anhydrous or hydroxyapatite nanoparticles were applied ex situ. Specimens without treatment served as controls. After a further 6 h of intraoral exposure, specimens were removed and analysed by scanning (n = 4 specimens per substance, in total) and transmission electron microscopy (n = 2 specimens per substance)., Results: Application of desensitizing agents resulted in the deposition of different structures on the dentin surface and occlusion of dentinal tubules., Conclusion: The ultrastructural analysis using transmission electron microscopy indicates that dentinal tubules were occluded under in-situ conditions not only by inorganic but also by organic deposits from the oral cavity., Competing Interests: Conflict of interest None disclosed., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Surfactants are important components of oral care products. Sodium dodecyl sulfate (SDS) is the most common because of its foaming properties, taste and low cost. However, the use of ionic surfactants, especially SDS, is related to several oral mucosa conditions. Thus, there is a high interest in using non-ionic and amphoteric surfactants as they are less irritant. To better understand the performance of these surfactants in oral care products, we investigated their interaction with salivary pellicles i.e., the proteinaceous films that cover surfaces exposed to saliva. Specifically, we focused on pentaethylene glycol monododecyl ether (C12E5) and cocamidopropyl betaine (CAPB) as model nonionic and amphoteric surfactants respectively, and investigated their interaction with reconstituted salivary pellicles with various surface techniques: Quartz Crystal Microbalance with Dissipation, Ellipsometry, Force Spectroscopy and Neutron Reflectometry. Both C12E5 and CAPB were gentler on pellicles than SDS, removing a lower amount. However, their interaction with pellicles differed. Our work indicates that CAPB would mainly interact with the mucin components of pellicles, leading to collapse and dehydration. In contrast, exposure to C12E5 had a minimal effect on the pellicles, mainly resulting in the replacement/solubilisation of some of the components anchoring pellicles to their substrate. [ABSTRACT FROM AUTHOR]

The salivary pellicle plays an important role in oral physiology, yet noninvasive in situ characterization and mapping of this layer remains elusive. The goal of this study is to develop an optical approach for the real-time, noninvasive mapping and characterization of salivary pellicles using optical coherence tomography (OCT) and optical coherence microscopy (OCM). The long-term goals are to improve diagnostic capabilities in the oral cavity, gain a better understanding of physiological and pathological processes related to the oral hard tissues, and monitor treatment responses. A salivary pellicle is incubated on small enamel cubes using human whole saliva. OCT and OCM imaging occurs at 0, 10, 30, 60 min, and 24 h. For some imaging, spherical gold nanoparticles (15 nm) are added to determine whether this would increase the optical signal from the pellicle. Multiphoton microscopy (MPM) provides the baseline information. In the saliva-incubated samples, a surface signal from the developing pellicle is visible in OCT images. Pellicle "islands" form, which increase in complexity over time until they merge to form a continuous layer over the enamel surface. Noninvasive, in situ time-based pellicle formation on the enamel surface is visualized and characterized using optical imaging.

Pellicle is the initial proteinaceous layer that is formed almost instantaneously on all solid surfaces in the oral cavity. It is of essential relevance for any interactions and metabolism on the tooth surface. Up to now, there is no information on the metabolome of this structure. Accordingly, the present study aims to characterise the metabolomic profile of in-situ pellicle in children with different caries activity for the first time in comparison to saliva. Small molecules such as carbohydrates, amino acids, organic acids, and fatty acids, putatively involved in the formation of caries were quantified using mass spectrometry (MS)-based techniques, such as (stable isotope dilution analysis)-ultra-performance liquid chromatography-tandem MS and gas chromatography/electron ionisation-MS. Pellicle and corresponding saliva samples were collected from caries-active, caries-free and caries-rehabilitated 4- to 6-year-old children. The most abundant analytes in pellicle were acetic acid (1.2–10.5 nmol/cm2), propionic acid (0.1–8.5 nmol/cm2), glycine (0.7–3.5 nmol/cm2), serine (0.08–2.3 nmol/cm2), galactose (galactose + mannose; 0.035–0.078 nmol/cm2), lactose (0.002–0.086 nmol/cm2), glucose (0.018–0.953 nmol/cm2), palmitic acid (0.26–2.03 nmol/cm2), and stearic acid (0.34–1.81 nmol/cm2). Significant differences depending on caries activity were detected neither in saliva nor in the corresponding pellicle samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • First systematic examination of the in situ pellicle thickness. • Ellipsometry is a powerful method for measurements of pellicle thickness. • A physiologically important rapid initial pellicle formation stage was detected. • Inter-individual and formation kinetics differences were found. • Oral location had a lower impact on pellicle thickness than individual influence. Abstract The salivary pellicle is a thin acellular film formed on orally exposed surfaces by adsorption of macromolecules from the oral fluids and serves as a protective layer in the maintenance of oral health. Pellicle thickness measurements are a central tool helping to understand how exogenous manipulations may influence pellicle formation. This is of particular importance for the investigation of new preventive and therapeutic approaches. In the present study we determined the kinetics of the in situ pellicle thickness formation at different intraoral sites and investigated how pellicle formation occurs in different individuals. To address the kinetic aspect, the thickness of the in situ pellicle was determined after formation periods of 3 min, 30 min and 120 min. The thickness of the pellicle was either measured on silicon wafers by ellipsometry or on bovine enamel by transmission electron microscopy. We found a physiologically important rapid pellicle formation phase within the first minutes and a slow pellicle formation phase between 30 min and 120 min. Furthermore, our results identify significant inter-individual differences both for the pellicle thickness and for the formation kinetics, indicating the consideration of individual-specific differences of the pellicle layer as an important aspect for future studies. [ABSTRACT FROM AUTHOR]

Introduction: Dental erosion is defined as the pathological, irreversible, chronic, and localised loss of dental enamel by prolonged acid action and often without bacterial involvement. Aim: To evaluate ex vivo, the erosive potential of widely consumed teas in Brazil by measuring the pH, titratable acidity of beverages and the roughness and surface microhardness of dental enamel before and after erosive challenges. Materials and Methods: Thirty human maxillary third molars, extracted for clinical reasons and obtained from Human Teeth Bank of the Dental School from 8th May 2017 to 18th May 2017 (Federal University of Juiz de Fora), were used to perform erosive cycles, which were exposed to Morinda citrifolia, Uncaria tomentosa, Caesalpinia ferrea, Schizolobium amazonicum, Schinus aroeira teas and 1% citric acid. The samples were immersed in the solutions for two minute, five times a day, at intervals of two hours for four days. Between the erosive cycles, the specimens remained in artificial saliva. Statistical analyses were performed using the IBM SPSS statistics 22.0 software. The accepted significance was set has p-value <0.05. Results: The mean pH of the five samples ranged from 3.55 to 5.55 and all the herbal teas tested showed significant buffering capacity. The results suggested that all acid teas in the study have an erosive potential. The microhardness ranged from 34.12 to 46.98, and no significant difference was observed between groups in relation to the control group (1% citric acid). The roughness results for M. citrifolia and U. tomentosa teas were similar to those of the control group. Conclusion: The analysis of the data allows for the conclusion that all the teas present with acid pH and presence of ions capable of interacting with the dental surface and causing loss of dental tissue, reducing the microhardness of the enamel. Thus, there is a need to be careful in consuming such beverages. [ABSTRACT FROM AUTHOR]

Hydroxyapatite-based implant is widely used in the fields of artificial teeth and bones. However, the problem of microbial communities on hydroxyapatite surfaces remain a great challenge. In order to inhibit bacterial adhesion and activity in a long term, a salivary acquired pellicle (SAP) bioinspired tannic acid (SAP3-TA) is synthesized and characterized. The SAP inspired peptide sequence DDDEEK has a good adsorption performance on the surface of hydroxyapatite (HA). Tannic acid (TA) is a natural polyphenolic compound that can be extracted from green tea, and it has been proved to have an effective antibacterial property. After the coating of SAP3-TA on HA slices, the water contact angle is decreased to 14.2° and the HA surface becomes super-hydrophilic. The hydrophilic surface can prevent proteins adhesion and further inhibit the adhesion of bacteria. In this work, Streptococcus mutans ( S. mutans ) and bovine serum albumin (BSA) are used as models to prove the antibacterial and anti-biofouling properties of SAP3-TA coating on HA surface, respectively. SAP3-TA also shows low cytotoxicity to MG63 cells in the MTT test. All these results indicate that the SAP3-TA can be used as a potential antibacterial and anti-biofouling coating for hydroxyapatite-based implants. [ABSTRACT FROM AUTHOR]

The aim of this in-vivo study was to compare total protein and four key salivary proteins present in the acquired enamel pellicle (AEP) on eroded and non-eroded surfaces in participants with erosive tooth wear. Participants with erosive tooth wear of dietary non-intrinsic origin, present on the occlusal surfaces of the lower first molars and an unaffected posterior occlusal surface in the same quadrant were recruited from restorative dental clinics at King’s College London Dental Institute (n = 29, REC ref 14/EM/1171). Following removal of the salivary film, AEP samples were collected from the eroded occlusal surfaces (EP, n = 29) and the non-eroded occlusal surfaces (NP, n = 29) using 0.5% sodium dodecyl sulfate (SDS) soaked filter papers. Total protein concentration was analysed using bicinchoninic acid assay (BCA). Protein fractions were separated using SDS-PAGE and immunoblotted against: mucin5b, albumin, carbonic anhydrase VI (CA VI) and statherin antibodies. Amounts were quantified using ImageLab software against purified protein standards of known concentration. ANOVA followed by paired t-test and Wilcoxon’s matched-pair signed-rank test were used to test statistical significance. The difference was considered to be significant at a P value < 0.05. The total protein on eroded surfaces was significantly lower compared to the total protein on non-eroded surfaces [0.41mg/mL (0.04) and 0.61 mg/mL (0.11)] respectively (p< 0.05). The median (min, max) amount of statherin was also significantly lower on eroded occlusal surfaces [84.1 (20.0, 221.8) ng] compared to AEP from non-eroded teeth in the same subjects [97.1(30.0, 755.6) ng] (p = 0.002). No statistical differences were observed for mucin 5b, albumin or CA VI. The total protein and statherin in the in-vivo AEP were different between eroded and non-eroded tooth surfaces of the same patient. [ABSTRACT FROM AUTHOR]

Peptides descended from the salivary proteins statherin and histatin were recently identified in saliva and the acquired enamel pellicle (AEP), a proteomic layer coated on enamel. In particular, the statherin phosphopeptide DpSpSEEKFLR (DSS) was found to adsorb to enamel-like hydroxyapatite and inhibit plaque-related crystal formation. To determine the mechanism of these processes, we studied peptide-crystal interactions based on the sequences DSS and RKFHEKHHSHRGYR (RKF). The latter is a basic histatin sequence showing antimicrobial effects. To initiate crystallization we used calcium oxalate monohydrate (COM), a rather secondary phase in the oral environment, however highly amenable to experimental analyses of nucleation and growth processes. Using electron microscopy we found that the peptides DSS, DSS-RKF and DSS-DSS all inhibit crystal formation; with DSS-DSS showing the strongest effects while RKF showed no effect. In addition, using either enamel-like or mica substrates, we found that the ratio of the substrate's surface charge densities was directly correlated with the ratio of COM nucleation rates on theses surfaces. The findings suggest that mineralization processes on enamel/AEP-films are controllable by the degree of peptide phosphorylation/acidity and the level of the enamel surface charge density. Both parameters can, when well adjusted, help to overcome periodontal disease and dental calculus formation. In addition, the presence of antimicrobial RKF will reduce the buildup of bacterial plaque. [ABSTRACT FROM AUTHOR]

The salivary pellicle, covering natural as well as restored tooth surfaces in the oral cavity as an immobilized protein-rich layer, acts as an important physico-chemical and biological mediator at the tooth-saliva-interface. For the first time, the pellicle’s proteome of individual volunteers were analyzed separately on three consecutive days and the relative protein abundance determined by a label-free quantitative nano-LC–MS/MS approach. A total of 72 major proteins were identified in the initial pellicles formed intraorally on dental ceramic specimens already after 3 min with high inter-individual and inter-day consistency. In comparison, significant differences in protein abundance were evident between subjects, thus indicating unique individual pellicle profiles. Furthermore, the relative protein abundance in pellicles was compared to the proteome pattern in the corresponding saliva samples of the same individuals to provide first data on significantly enriched and depleted salivary proteins ( p < 0.05) within the surface-bound salivary pellicle. Our findings reveal the initial adsorption of salivary proteins at the solid-liquid interface to be a rapid, highly selective, and reproducible process leading to the immobilization of a broad range of protective proteins and enzymes on the substratum surface within a few minutes. This provides evidence that the pellicle layer might be physiologically functional even without further maturation. [ABSTRACT FROM AUTHOR]

The main oral manifestation of gastroesophageal reflux disease is dental erosion. The very few studies have evaluated the damage and changes of soft, periodontal tissues and microbial flora. The aim of this study was to measure mutant streptococci and lactobacilli counts as predisposing factors to dental caries using Dentocult SM® and Dentocult LB® tests.The results showed lower counts of Streptocococcus mutans and lactobacilli, that means lower predisposing factor to dental caries. These results suggest that demineralization of hard dental tissues is without cariogenic plaque.

Background/Aim. One of the preconditions for efficacious systematic reduction of caries prevalence and prophylaxis is the determination of risks of this disease appearance. The aim of this study was to prove the significance of salivary carboanhydrase activity determination in estimation of caries risk in children. Methods. The study included 123 children of average age of 13.4±0.3 years and permanent dentition. The children were divided into two groups according to caries risk (low and high caries risk groups). Two samples of saliva - unstimulated and stimulated one were taken from each child. Salivary carboanhydrase activity, as well as pH value, bicarbonate and phosphate buffer levels were estimated in both group of saliva samples. Results. The investigation showed significantly higher carboanhydrase activity (p < 0.001) in both saliva samples in low caries risk group compared to high caries risk one. In children with low caries risk, both unstimulated and stimulated saliva show significantly higher bicarbonate and phosphate buffer concentrations (p < 0.001), as well as pH values. Conclusion. The lower caries incidence could be expected in children with high carboanhydrase activity and higher salivary buffer system parameters levels. The presented results suggest that salivary carboanhydrase activity represents the important marker of individual susceptibility for caries appearance in children.

ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter species) pathogens have characteristic multiple-drug resistance and cause an increasing number of nosocomial infections worldwide. Peptide-based therapeutics to treat ESKAPE infections might be an alternative to conventional antibiotics. Histatin 5 (Hst 5) is a salivary cationic histidine-rich peptide produced only in humans and higher primates. It has high antifungal activity against Candida albicans through an energy-dependent, non-lytic process; but its bactericidal effects are less known. We found Hst 5 has bactericidal activity against S. aureus (60-70% killing) and A. baumannii (85-90% killing) in 10 and 100mM sodium phosphate buffer (NaPB), while killing of >99% of P. aeruginosa, 60-80% E. cloacae and 20-60% of E. faecium was found in 10 mM NaPB. Hst 5 killed 60%of biofilmcells of P. aeruginosa, but had reduced activity against biofilms of S. aureus and A. baumannii. Hst 5 killed 20% of K. pneumonia biofilm cells but not planktonic cells. Binding and uptake studies using FITC-labeled Hst 5 showed E. faecium and E. cloacae killing required Hst 5 internalization and was energy dependent, while bactericidal activity was rapid against P. aeruginosa and A. baumannii suggesting membrane disruption. Hst 5-mediated killing of S. aureus was both non-lytic and energy independent. Additionally, we found that spermidine conjugated Hst 5 (Hst5-Spd) had improved killing activity against E. faecium, E. cloacae, and A. baumannii. Hst 5 or its derivative has antibacterial activity against five out of six ESKAPE pathogens and may be an alternative treatment for these infections. [ABSTRACT FROM AUTHOR]

The repair of early dental caries lesions has been demonstrated by the application of the remineralisation technology based on casein phosphopeptide-stabilised amorphous calcium phosphate complexes (CPP-ACP). These complexes consist of an amorphous calcium phosphate mineral phase stabilised and encapsulated by the self-assembly of milk-derived phosphopeptides. During topical application of CPP-ACP complexes in the oral cavity, the CPP encounters the enamel pellicle consisting of salivary proteins and peptides. However the interactions of the CPP with the enamel salivary pellicle are not known. The studies presented here reveal that the predominant peptides of CPP-ACP complexes do interact with specific salivary proteins and peptides of the enamel pellicle, and provide a mechanism by which the CPP-ACP complexes are localised at the tooth surface to promote remineralisation. [ABSTRACT FROM AUTHOR]

In contrast to pellicles formed in vivo, pellicles formed in vitro provide little to no erosion protection for enamel, possibly due to protein degradation from proteases during pellicle formation. With the objective to achieve a more similar effect as observed for in vivo pellicles, the effects of adding protease inhibitors (PI) to saliva in vitro, and/or exchanging saliva repeatedly during pellicle formation were investigated in a cyclic model of pellicle formation and erosion with human enamel specimens. We repeatedly assessed surface microhardness (SMH), measured initial and final surface reflection intensity (SRI), and determined calcium released during erosion. For all the parameters tested, we observed a clear positive effect on erosion protection when adding PI to saliva for pellicle formation: SMH remained harder, SRI remained higher, and less calcium was released. Additionally, exchanging saliva with fresh one during pellicle formation led to a protective effect, but not as strong as the addition of PI. We conclude that adding protease inhibitors to saliva in vitro for pellicle formation leads to an erosion protective effect, which was further increased by repeatedly exchanging the saliva. Whether the pellicle itself more closely resembles in vivo pellicles remains to be investigated., (© 2023. The Author(s).)

Objectives: To verify the protective effect of plant extracts associated with fluoride against dental erosion of dentine, in the presence and absence of a salivary pellicle., Methods: Dentine specimens (n = 270) were randomly distributed into 9 experimental groups (n = 30/group): GT (green tea extract); BE (blueberry extract); GSE (grape seed extract); NaF (sodium fluoride); GT+NaF (green tea extract and NaF); BE+NaF (blueberry extract and NaF); GSE+NaF (grape seed extract and NaF); negative control (deionized water); and a positive control (commercialized mouthrinse containing stannous and fluoride). Each group was further divided into two subgroups (n = 15), according to the presence (P) or absence (NP) of salivary pellicle. The specimens were submitted to 10 cycles: 30 min incubation in human saliva (P) or only in humid chamber (NP), 2 min immersion in experimental solutions, 60 min of incubation in saliva (P) or not (NP), and 1 min erosive challenge. Dentine surface loss (dSL-10 and dSL-total), amount of degraded collagen (dColl) and total calcium release (CaR) were evaluated. Data were analyzed with Kruskal-Wallis, Dunn's and Mann-Whitney U tests (p>0.05)., Results: Overall, the negative control presented the highest values of dSL, dColl and CaR, and the plant extracts showed different degrees of dentine protection. For the subgroup NP, GSE showed the best protection of the extracts, and the presence of fluoride generally further improved the protection for all extracts. For the subgroup P, only BE provided protection, while the presence of fluoride had no impact on dSL and dColl, but lowered CaR. The protection of the positive control was more evident on CaR than on dColl., Conclusion: We can conclude that the plant extracts showed a protective effect against dentine erosion, regardless of the presence of salivary pellicle, and that the fluoride seems to improve their protection., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Niemeyer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

To investigate the effect of some polyphenol-rich plant extracts on the protection of dentine against demineralization, both acting on the dentine and on the salivary pellicle. Dentine specimens (n = 180) were randomly distributed into 6 experimental groups (n = 30/group): Control (deionized water), Açaí extract, Blueberry extract, Green tea extract, Grape seed extract, and Sn 2+ /F - (mouthrinse containing stannous and fluoride). Each group was further divided into two subgroups (n = 15), according to the site of action of the substance: on the dentine surface (D) or on the salivary pellicle (P). The specimens were submitted to 10 cycles: 30 min incubation in human saliva (P) or only in humid chamber (D), 2 min immersion in experimental substances, 60 min of incubation in saliva (P) or not (D), and 1 min erosive challenge. Dentine surface loss (DSL), amount of degraded collagen (dColl) and total calcium release were analyzed. Green tea, Grape seed and Sn 2+ /F - showed significant protection, with least DSL and dColl. The Sn 2+ /F - showed better protection on D than on P, whereas Green tea and Grape seed showed a dual mode of action, with good results on D, and even better on P. Sn 2+ /F - showed the lowest values of calcium release, not differing only from Grape seed. Sn 2+ /F - is more effective when acting directly on the dentine surface, while Green tea and Grape seed have a dual mode of action: with a positive effect on the dentine surface itself, but an improved efficacy in the presence of the salivary pellicle. We further elucidate the mechanism of action of different active ingredients on dentine erosion, where Sn 2+ /F - acts better on the dentine surface, but plant extracts have a dual mode of action, acting on the dentine itself as well as on the salivary pellicle, improving the protection against acid demineralization., (© 2023. The Author(s).)

Gluconacetobacter xylinus (formerly Acetobacter xylinum and presently Komagataeibacter medellinensis) is known to produce cellulose as a stable pellicle. However, it is also well known to lose this ability very easily. We investigated the on and off mechanisms of cellulose producibility in two independent cellulose-producing strains, R1 and R2. Both these strains were isolated through a repetitive static culture of a non-cellulose-producing K. medellinensis NBRC 3288 parental strain. Two cellulose synthase operons, types I and II, of this strain are truncated by the frameshift mutation in the bcsBI gene and transposon insertion in the bcsCII gene, respectively. The draft genome sequencing of R1 and R2 strains revealed that in both strains the bcsBI gene was restored by deletion of a nucleotide in its C-rich region. This result suggests that the mutations in the bcsBI gene are responsible for the on and off mechanism of cellulose producibility. When we looked at the genomic DNA sequences of other Komagataeibacter species, several non-cellulose-producing strains were found to contain similar defects in the type I and/or type II cellulose synthase operons. Furthermore, the phylogenetic relationship among cellulose synthase genes conserved in other bacterial species was analyzed. We observed that the cellulose genes in the Komagataeibacter shared sequence similarities with the γ-proteobacterial species but not with the α-proteobacteria and that the type I and type II operons could be diverged from a same ancestor in Komagataeibacter. [ABSTRACT FROM AUTHOR]

Objectives: To compare the effects of stannous (Sn) and fluoride (F) ions and their combination on acquired enamel pellicle (AEP) protein composition (proteome experiment), and protection against dental erosion (functional experiment). Methods: In the proteome experiment, bovine enamel specimens were incubated in whole saliva supernatant for 24h for AEP formation. They were randomly assigned to 4 groups (n=10), according to the rinse treatment: Sn (800ppm/6.7mM, SnCl2), F (225ppm/13mM, NaF), Sn and F combination (Sn+F) and deionized water (DIW, negative control). The specimens were immersed 3× in the test rinses for 2min, 2h apart. Pellicles were collected, digested, and analyzed for protein content using liquid chromatography electrospray ionization tandem mass spectrometry. In the functional experiment, bovine enamel specimens (n=10) were similarly treated for pellicle formation. Then, they were subjected to a five-day erosion cycling model, consisting of 5min erosive challenges (15.6 mM citric acid, pH 2.6, 6×/d) and 2min treatment with the rinses containing Sn, F or Sn+F (3×/d). Between the treatments, all specimens were incubated in whole saliva supernatant. Surface loss was determined by profilometry. Results: Our proteome approach on bovine enamel identified 72 proteins that were common to all groups. AEP of enamel treated with Sn+F demonstrated higher abundance for most of the identified proteins than the other groups. The functional experiment showed reduction of enamel surface loss for Sn+F (89%), Sn (67%) and F (42%) compared to DIW (all significantly different, p<0.05). Conclusion: This study highlighted that anti-erosion rinses (e.g. Sn+F) can modify quantitatively and qualitatively the AEP formed on bovine enamel. Moreover, our study demonstrated a combinatory effect that amplified the anti-erosive protection on tooth surface. [ABSTRACT FROM AUTHOR]

Highlights: [•] Largely protein showed the ability to bind through hydrophobic interactions, yet some also bind according to their charges. [•] The hydrophobic surfaces showed the closest match to the known bound mucosal pellicle. [•] Salivary protein binding to particles was improved in some samples when incubated with transglutaminase. [ABSTRACT FROM AUTHOR]