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Materials (Basel, Switzerland) Mar 2023The microbiological behavior of dental polymer materials is crucial to secure the clinical success of dental restorations. Here, the manufacturing process and the...
The microbiological behavior of dental polymer materials is crucial to secure the clinical success of dental restorations. Here, the manufacturing process and the machining can play a decisive role. This study investigated the bacterial adhesion on dental polymers as a function of manufacturing techniques (additive/subtractive) and different polishing protocols. Specimens were made from polyaryletherketone (PEEK, PEKK, and AKP), resin-based CAD/CAM materials (composite and PMMA), and printed methacrylate (MA)-based materials. Surface roughness (R; R) was determined using a laser scanning microscope, and SFE/contact angles were measured using the sessile drop method. After salivary pellicle formation, in vitro biofilm formation was initiated by exposing the specimens to suspensions of () and (). Adherent bacteria were quantified using a fluorometric assay. One-way ANOVA analysis found significant influences ( < 0.001) for the individual parameters (treatment and material) and their combinations for both types of bacteria. Stronger polishing led to significantly ( < 0.001) less adhesion of (Pearson correlation PC = -0.240) and (PC = -0.206). A highly significant ( = 0.010, PC = 0.135) correlation between adhesion and R was identified. Post hoc analysis revealed significant higher bacterial adhesion for vertically printed MA specimens compared to horizontally printed specimens. Furthermore, significant higher adhesion of on pressed PEEK was revealed comparing to the other manufacturing methods (milling, injection molding, and 3D printing). The milled PAEK samples showed similar bacterial adhesion. In general, the resin-based materials, composites, and PAEKs showed different bacterial adhesion. Fabrication methods were shown to play a critical role; the pressed PEEK showed the highest initial accumulations. Horizontal DLP fabrication reduced bacterial adhesion. Roughness < 10 µm or polishing appear to be essential for reducing bacterial adhesion.
PubMed: 36984253
DOI: 10.3390/ma16062373 -
Journal of Applied Oral Science :... 2009Dental erosion is defined as the loss of tooth substance by acid exposure not involving bacteria. The etiology of erosion is related to different behavioral, biological... (Review)
Review
Dental erosion is defined as the loss of tooth substance by acid exposure not involving bacteria. The etiology of erosion is related to different behavioral, biological and chemical factors. Based on an overview of the current literature, this paper presents a summary of the preventive strategies relevant for patients suffering from dental erosion. Behavioral factors, such as special drinking habits, unhealthy lifestyle factors or occupational acid exposure, might modify the extent of dental erosion. Thus, preventive strategies have to include measures to reduce the frequency and duration of acid exposure as well as adequate oral hygiene measures, as it is known that eroded surfaces are more susceptible to abrasion. Biological factors, such as saliva or acquired pellicle, act protectively against erosive demineralization. Therefore, the production of saliva should be enhanced, especially in patients with hyposalivation or xerostomia. With regard to chemical factors, the modification of acidic solutions with ions, especially calcium, was shown to reduce the demineralization, but the efficacy depends on the other chemical factors, such as the type of acid. To enhance the remineralization of eroded surfaces and to prevent further progression of dental wear, high-concentrated fluoride applications are recommended. Currently, little information is available about the efficacy of other preventive strategies, such as calcium and laser application, as well as the use of matrix metalloproteinase inhibitors. Further studies considering these factors are required. In conclusion, preventive strategies for patients suffering from erosion are mainly obtained from in vitro and in situ studies and include dietary counseling, stimulation of salivary flow, optimization of fluoride regimens, modification of erosive beverages and adequate oral hygiene measures.
Topics: Calcium; Diet Therapy; Fluorides; Humans; Laser Therapy; Oral Hygiene; Saliva; Tissue Inhibitor of Metalloproteinases; Tooth Erosion; Tooth Remineralization
PubMed: 19274390
DOI: 10.1590/s1678-77572009000200002 -
Scientific Reports Sep 2019One mechanism of action for the anticaries effect of topical fluoridation is through precipitation of CaF. In this in vitro study energy-dispersive x-ray spectroscopy...
One mechanism of action for the anticaries effect of topical fluoridation is through precipitation of CaF. In this in vitro study energy-dispersive x-ray spectroscopy (EDX) is used as a semiquantitative method to detect enamel fluoride-precipitation under the influence of acidic and neutral pH-value and absence or presence of a salivary pellicle. Crowns of 30 human caries-free third molars were quartered into four specimens and the enamel surface ground flat and polished. Two specimens each were stored in human saliva (120 minutes pellicle formation). Teeth were randomly allocated into 6 treatment groups: NaF_a (experimental acidic sodium fluoride; 12500 ppmF, pH 4.75); NaF_n (experimental neutral sodium fluoride; 12500 ppmF, pH 7.0); GB_a (acidic gel base; 0 ppmF, pH 4.75); GB_n (neutral gel base; 0 ppmF, pH 7.0); AmF-NaF_a (experimental acidic amine/sodium fluoride; 12500 ppmF, pH 4.75); EG_a (acidic amine/sodium fluoride; Elmex Geleé, CP-GABA GmbH; 12500 ppmF, pH 4.75). Each gel was applied for 60 seconds to one specimen with and one specimen without pellicle. Two specimens served as controls (no gel, without/with pellicle). Atomic percent (At%) of O, F, Na, Mg, P, Ca was measured by EDX. ∆At% and Ca/P-ratios were calculated. EDX could semi-quantify superficial enamel fluoride-precipitation. Only specimens treated with acidic fluoride gels showed fluoride-precipitation, a salivary pellicle tended to decrease At%F.
Topics: Administration, Topical; Calcium Fluoride; Dental Enamel; Gels; Humans; Molar, Third; Spectrometry, X-Ray Emission
PubMed: 31530840
DOI: 10.1038/s41598-019-49742-5 -
Clinical Oral Investigations Nov 2021This in situ study aimed to determine and compare the chlorhexidine (CHX) retention in the oral cavity after the application of different CHX pharmaceutical regimens.
OBJECTIVES
This in situ study aimed to determine and compare the chlorhexidine (CHX) retention in the oral cavity after the application of different CHX pharmaceutical regimens.
METHODS
Five volunteers used different CHX treatment regimens including mouth rinses, dental spray and toothpaste gel. After the application of the different CHX regimens, 2-μl samples were taken from saliva and buccal mucosa pellicle as well as the dental pellicle samples formed on standardized enamel surfaces. Sample collection was conducted at six time points within 12 h. Retention of CHX was measured using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.
RESULTS
CHX retention values in the oral mucosa pellicle were significantly higher than those in saliva. CHX remained in the mucosal pellicle at microgrammes per millilitre levels for 12 h after mouth rinsing, 10 h after spray application and 2 h after using the toothpaste. CHX was detected in the dental pellicle for at least 12 h after application of mouth rinsing and spray. Retention of CHX after mouth rinsing or spray application was significantly higher than the retention after using toothpaste.
CONCLUSIONS
Oral mucosa was the favourable site for CHX retention. Higher mouth rinse concentration and longer rinsing time produced a slight increase in CHX retention. CHX spray provided considerable retention values, whereas toothpaste gel delivered the lowest retention after application. MALDI-TOF was a sensitive method with excellent limits of quantification for CHX detection.
Topics: Anti-Infective Agents, Local; Chlorhexidine; Humans; Mouth; Mouthwashes; Saliva; Toothpastes
PubMed: 33825020
DOI: 10.1007/s00784-021-03910-y -
Brazilian Oral Research 2013The purpose of this study was to evaluate the influence of the substratum position and the saliva acquired pellicle (AP) on Candida albicans biofilm development....
The purpose of this study was to evaluate the influence of the substratum position and the saliva acquired pellicle (AP) on Candida albicans biofilm development. Poly(methylmethacrylate) (PMMA) disks were fabricated and randomly allocated to experimental groups: HNP (disks placed in a horizontal position and uncoated by pellicle), VNP (disks placed in a vertical position and uncoated by pellicle), HCP (disks placed in a horizontal position and coated by pellicle), and VCP (disks placed in a vertical position and coated by pellicle). Disks were placed in a 24-well plate and a suspension of 107 cells/mL of Candida albicans was added to each well for biofilm development. The plates were aerobically incubated at 35°C. The biofilms were evaluated at 1.5 (adhesion time point), 24, 48, 72, and 96 hours. The number of viable cells was quantified in terms of the colony-forming units per milliliter (CFU/mL). Metabolic activity was measured by the XTT assay. The biofilm structure was analyzed by scanning electron microscopy. The data were analyzed by three-way ANOVA followed by Tukey's test, with significance set at 5%. The vertical groups showed less biofilm formation and lower metabolic activity than the horizontal groups (p<0.05). Significant differences in cell viability and metabolic activity were observed between the adhesion and other time points (p<0.05), but these variables were not affected by the presence of the pellicle (p>0.05). It can be concluded that the substratum position influenced biofilm development.
Topics: Analysis of Variance; Biofilms; Candida albicans; Colony-Forming Units Assay; Dental Pellicle; Microscopy, Electron, Scanning; Polymethyl Methacrylate; Random Allocation; Saliva; Surface Properties; Time Factors
PubMed: 23780496
DOI: 10.1590/S1806-83242013005000020 -
Microbiology Spectrum Aug 2022The number of bacterial species recognized to utilize purposeful amyloid aggregation within biofilms continues to grow. The oral pathogen Streptococcus mutans produces...
The number of bacterial species recognized to utilize purposeful amyloid aggregation within biofilms continues to grow. The oral pathogen Streptococcus mutans produces several amyloidogenic proteins, including adhesins P1 (also known as AgI/II, PAc) and WapA, whose truncation products, namely, AgII and AgA, respectively, represent the amyloidogenic moieties. Amyloids demonstrate common biophysical properties, including recognition by Thioflavin T (ThT) and Congo red (CR) dyes that bind to the cross β-sheet quaternary structure of amyloid aggregates. Previously, we observed amyloid formation to occur only after 60 h or more of S. mutans biofilm growth. Here, we extend those findings to investigate where amyloid is detected within 1- and 5-day-old biofilms, including within tightly adherent compared with those in nonadherent fractions. CR birefringence and ThT uptake demonstrated amyloid within nonadherent material removed from 5-day-old cultures but not within 1-day-old or adherent samples. These experiments were done in conjunction with confocal microscopy and immunofluorescence staining with AgII- and AgA-reactive antibodies, including monoclonal reagents shown to discriminate between monomeric protein and amyloid aggregates. These results also localized amyloid primarily to the nonadherent fraction of biofilms. Lastly, we show that the C-terminal region of P1 loses adhesive function following amyloidogenesis and is no longer able to competitively inhibit binding of S. mutans to its physiologic substrate, salivary agglutinin. Taken together, our results provide new evidence that amyloid aggregation negatively impacts the functional activity of a widely studied S. mutans adhesin and are consistent with a model in which amyloidogenesis of adhesive proteins facilitates the detachment of aging biofilms. Streptococcus mutans is a keystone pathogen and causative agent of human dental caries, commonly known as tooth decay, the most prevalent infectious disease in the world. Like many pathogens, S. mutans causes disease in biofilms, which for dental decay begins with bacterial attachment to the salivary pellicle coating the tooth surface. Some strains of S. mutans are also associated with bacterial endocarditis. Amyloid aggregation was initially thought to represent only a consequence of protein mal-folding, but now, many microorganisms are known to produce functional amyloids with biofilm environments. In this study, we learned that amyloid formation diminishes the activity of a known S. mutans adhesin and that amyloid is found within the nonadherent fraction of older biofilms. This finding suggests that the transition from adhesin monomer to amyloid facilitates biofilm detachment. Knowing where and when S. mutans produces amyloid will help in developing therapeutic strategies to control tooth decay and other biofilm-related diseases.
Topics: Adhesins, Bacterial; Aging; Amyloid; Amyloidogenic Proteins; Biofilms; Dental Caries; Humans; Streptococcus mutans
PubMed: 35950854
DOI: 10.1128/spectrum.01661-22 -
Scientific Reports Feb 2018The aim of this study was to test the hypothesis that duplication/hybridization of functional domains of naturally occurring pellicle peptides amplified the inhibitory...
The aim of this study was to test the hypothesis that duplication/hybridization of functional domains of naturally occurring pellicle peptides amplified the inhibitory effect of hydroxyapatite crystal growth, which is related to enamel remineralization and dental calculus formation. Histatin 3, statherin, their functional domains (RR14 and DR9), and engineered peptides (DR9-DR9 and DR9-RR14) were tested at seven different concentrations to evaluate the effect on hydroxyapatite crystal growth inhibition. A microplate colorimetric assay was used to quantify hydroxyapatite crystal growth. The half-maximal inhibitory concentration (IC) was determined for each group. ANOVA and Student-Newman-Keuls pairwise comparisons were used to compare the groups. DR9-DR9 increased the inhibitory effect of hydroxyapatite crystal growth compared to single DR9 (p < 0.05), indicating that functional domain multiplication represented a strong protein evolution pathway. Interestingly, the hybrid peptide DR9-RR14 had an intermediate inhibitory effect compared to DR9 and DR9-DR9. This study used an engineered peptide approach to investigate a potential evolution protein pathway related to duplication/hybridization of acquired enamel pellicle's natural peptide constituents, contributing to the development of synthetic peptides for therapeutic use against dental caries and periodontal disease.
Topics: Crystallization; Dental Enamel; Dental Pellicle; Durapatite; Engineering; Peptides; Protein Domains
PubMed: 29491390
DOI: 10.1038/s41598-018-21854-4 -
Caries Research 2008The aim was to analyze the protective effects of titanium, zirconium and hafnium tetrafluorides on erosion of pellicle-free and pellicle-covered enamel and dentine in... (Comparative Study)
Comparative Study
The aim was to analyze the protective effects of titanium, zirconium and hafnium tetrafluorides on erosion of pellicle-free and pellicle-covered enamel and dentine in vitro. Eight groups of 20 specimens each of bovine enamel and bovine dentine were prepared. Half the specimens in each group were immersed in human saliva for 2 h for pellicle formation. Specimens were then left untreated (controls) or were treated for 120 s with TiF(4), ZrF(4) or HfF(4) solutions (0.4 or 1%) or 1.25% AmF/NaF gel. All specimens were eroded by exposure to hydrochloric acid, pH 2.6, for 25 min. Cumulative calcium release into the acid was monitored in consecutive 30-second intervals for 5 min, then at 2-min intervals up to a total erosion time of 25 min using the Arsenazo III procedure. Data were analyzed by ANOVA. 1% TiF(4) solution offered the best protective effect, especially in dentine (reduction of calcium loss about 50% at 25 min). 1% ZrF(4), 1% HfF(4) and 0.4% TiF(4) also reduced calcium loss, but to a lesser extent. Long-term effects were limited to dentine, while reduction of enamel erosion (about 25%) was restricted to 1-min erosion. The fluoride gel had a protective effect only in dentine. The efficacy of the tetrafluorides was influenced by the presence of the pellicle layer, in that the protection against dentine erosion by TiF(4) and ZrF(4) was greater on pellicle-covered specimens. Tetrafluoride solutions, especially 1% TiF(4), could decrease dental erosion, but were more effective on dentine than on enamel.
Topics: Adult; Analysis of Variance; Animals; Cariostatic Agents; Cattle; Dental Enamel; Dental Pellicle; Dentin; Female; Fluorides; Fluorides, Topical; Hafnium; Humans; Hydrochloric Acid; Male; Middle Aged; Saliva; Titanium; Tooth Erosion; Treatment Outcome; Zirconium
PubMed: 18523383
DOI: 10.1159/000135669 -
Caries Research 2015The effectiveness of fluoride in caries prevention has been convincingly proven. In recent years, researchers have investigated the preventive effects of different... (Review)
Review
The effectiveness of fluoride in caries prevention has been convincingly proven. In recent years, researchers have investigated the preventive effects of different fluoride formulations on erosive tooth wear with positive results, but their action on caries and erosion prevention must be based on different requirements, because there is no sheltered area in the erosive process as there is in the subsurface carious lesions. Thus, any protective mechanism from fluoride concerning erosion is limited to the surface or the near surface layer of enamel. However, reports on other protective agents show superior preventive results. The mechanism of action of tin-containing products is related to tin deposition onto the tooth surface, as well as the incorporation of tin into the near-surface layer of enamel. These tin-rich deposits are less susceptible to dissolution and may result in enhanced protection of the underlying tooth. Titanium tetrafluoride forms a protective layer on the tooth surface. It is believed that this layer is made up of hydrated hydrogen titanium phosphate. Products containing phosphates and/or proteins may adsorb either to the pellicle, rendering it more protective against demineralization, or directly to the dental hard tissue, probably competing with H(+) at specific sites on the tooth surface. Other substances may further enhance precipitation of calcium phosphates on the enamel surface, protecting it from additional acid impacts. Hence, the future of fluoride alone in erosion prevention looks grim, but the combination of fluoride with protective agents, such as polyvalent metal ions and some polymers, has much brighter prospects.
Topics: Cariostatic Agents; Dental Enamel Solubility; Fluorides; Humans; Phosphates; Protective Agents; Protons; Tin Compounds; Tooth Erosion
PubMed: 25871415
DOI: 10.1159/000380886 -
Brazilian Oral Research 2023The 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...
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.
Topics: Humans; Dental Pellicle; Tandem Mass Spectrometry; Tooth Wear; Durapatite; Gastroesophageal Reflux
PubMed: 37729290
DOI: 10.1590/1807-3107bor-2023.vol37.0085