Properties Of Enamel Research Articles

Does the whitening dentifrice containing activated charcoal interfere with the properties of dental enamel? Microhardness, surface roughness and colorimetry analyzes.

The study evaluated the influence of whitening dentifrice containing activated charcoal on microhardness (MH), surface roughness (Ra) and colorimetry of tooth enamel. A total of 60 healthy bovine incisor teeth were used and divided into: G1 (regular non-whitening toothpaste), G2 (conventional whitening toothpaste), G3 (activated charcoal based whitening toothpaste) and G4 (10% carbamide peroxide gel - PC10). Groups G1, G2 and G3 underwent simulated toothbrushing for 14 days, while G4 received bleaching treatment for the same time. The readings of MH, Ra and colorimetry were performed before any intervention (T0 - baseline) and at the end of 14 days of the proposed treatments (T1). After confirming the normality of the data, the results of MH, Ra and colorimetry were subjected to 2-factor ANOVA for repeated measures (α = 5%). For MH, there were no statistical differences in G1, G2 and G3, only in G4. Considering Ra, a significant increase was observed in G2 and G3, with no statistical differences found in the other groups. Regarding colorimetry, the average color difference (ΔE) was greater in the G4 group (11.30 ± 4.31), even compared to the groups submitted to the whitening dentifrices: G2 (5.13 ± 2.75) and G3 (5.86 ± 3.66). It was concluded that the use of a whitening toothpaste containing activated charcoal caused deleterious effects on the enamel Ra, but did not affect the microhardness of the substrate, besides promoting a color change inferior to the regular non-bleaching toothpaste or PC10 gel. Key words:Whitening dentifrice, charcoal, roughness, microhardness.

Comparative evaluation of probiotic solutions on surface roughness and microhardness of different restorative materials and enamel.

This research study aimed to investigate the impact of probiotic mouthwash and kefir on the surface characteristics, specifically surface roughness and microhardness, of different restorative materials, as well as permanent and deciduous tooth enamels. Thirty disc-shaped specimens were prepared from composite resin (G-ænial Posterior (GP)), polyacid-modified composite resin (compomer) (Dyract-XP (DXP)), and resin-modified glass ionomer cement (Ionoseal (IS)). Additionally, thirty specimens of enamel were obtained from permanent teeth (PT) and thirty from deciduous teeth (DT) by embedding buccal and lingual sections, acquired through vertical sectioning of 15 permanent and 15 deciduous human tooth crowns in the mesiodistal orientation within acrylic resin blocks. The specimens were then categorized into three distinct groups and immersed for 14 days in one of the following solutions: distilled water, kefir or probiotic mouthwash. The mean surface roughness values of all specimens were assessed using an atomic force microscope, while the mean surface microhardness was measured using a Vickers hardness measuring instrument. The results revealed a statistically significant difference in mean surface roughness among the various restorative materials (p < 0.001). Among the restorative materials, the IS material exhibited notably higher mean surface roughness values than other restorative materials and tooth enamel, while no significant differences were observed between the PT and DT groups. Importantly, the main effect of the solutions under investigation was not statistically significant (p = 0.208). No significant difference was found between the surface roughness values of specimens subjected to the different solutions. When evaluating the effects of materials and solutions on microhardness, the main effects of material and solution variables and the influence of material-solution interactions were statistically significant (p < 0.001). Taken together, these results indicate that consistent use of kefir or probiotic mouthwashes may impact the surface properties of various restorative materials and tooth enamel.

Evaluation of Clinical Performance and Colour Match of Single and Multiple Shade Composites in Class-I Restorations: A Randomised Clinical Study

Introduction: Biomimetic dentistry primarily focuses on achieving aesthetics that closely resemble natural enamel and dentin. This approach ensures that dental restorations seamlessly match the appearance of enamel and dentin, rendering them virtually invisible. Additionally, biomimetic dentistry aims to mimic not only the visual characteristics but also the physical properties of enamel and dentin, thereby ensuring functional acceptability. The introduction of new composite materials in the market is a gradual progression aimed at attaining the mentioned objectives. Aim: To compare clinical performance and colour matching of single and multiple shade composites in simple Class-I carious lesions after one year. Materials and Methods: This randomised clinical study included 21 patients with a total of 72 Class-I carious lesions with patients who provided informed consent. Teeth were randomised into two groups: Group-A (n=36) received multishade composite (3M Filtek z350), and Group-B (n=36) received single-shade composite (Omnichroma). Clinical performance was assessed by two blinded evaluators at baseline, six months, and one year using modified United States Public Health Service (USPHS) criteria. Colour matching was evaluated by capturing digital photographs with a DSLR camera, ring flash, and 100 mm macro lens. Colour measurements (L*, a*, b*) were analysed using Adobe Photoshop, and ΔE was calculated immediately after restoration. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) 21.0 software, employing Chi-square test, Friedman test, and independent t-test. Results: No significant difference was found in clinical outcomes after one year using modified USPHS criteria (p&gt;0.05). However, both Group-A (p=0.002) and Group-B (p=0.007) showed increased marginal discolouration, and decreased colour match (p&lt;0.001) from baseline to one year. There was no statistically significant difference in colour matching potential between the two groups (p=0.056). Conclusion: Single-shade composites effectively treat Class-I carious lesions, demonstrating satisfactory colour matching and clinical performance.

Molar Incisor Hypomineralisation as a Dental Caries Risk Factor - Is It True?

The development of the human dentition is susceptible to disruption owing to its intricate and delicate nature, encompassing variations in tooth number, anatomical configuration, and the characteristics of enamel, dentine, and cementum. This chapter will specifically address the prevalent defect of molar incisor hypomineralisation (MIH), which can impose a significant treatment burden on individuals. MIH is linked to deleterious alterations in the properties of affected enamel, which can lead to rapid enamel breakdown and carious lesion formation in those at a heightened caries risk. In addition, MIH is associated with tooth sensitivity, dental anxiety, difficulty eating, aesthetic concerns, and negative influence during the child's psychological growth, especially when the MIH is severe. Regarding dental caries, it is essential to note that MIH does not directly increase the risk of caries. However, MIH can alter the way the caries process manifests by creating niches where biofilm can accumulate, complicating oral cleaning efforts. Additionally, MIH adversely modifies the physicochemical properties of enamel, influencing how this "hardest of tissues" responds to cariogenic challenges.

Мініінвазивні методи відновлення зубів в терапевтичній стоматології

Abstract. Photopolymer composite materials have unprecedented adhesion to hard tooth tissues and correspond to the optical properties of enamel and dentin. Due to these characteristics, photopolymers are widely used in aesthetic dentistry. The purpose of this work is to evaluate the results of the step-by-step acquisition by the dentist of the manual skills of using photopolymer materials. Methods of working with dental materials on models and in the oral cavity were used. The results showed that the technique of working with modern photopolymers requires excellent manual skills, mastering them and their improvement continues constantly with the appearance of new, more advanced tools and methods of treatment in dentistry. One of the effective ways of mastering innovative work methods is the production of temporary restorations from various materials. Conclusions. During the training stages of the dentist, in cases of remote temporary filling, a mini-invasive effect can be used, since it practically does not lead to the risk of damage to the tooth and involves the manufacture of an aesthetic restoration in the future in accordance with the protocol for the treatment of permanent teeth. Key words: photopolymer materials, minimally invasive treatment, manual skills, aesthetic restoration, adhesion.

Effect of incorporation of calcium polyphosphate sub-microparticles in low-concentration bleaching gels on physical properties of dental enamel.

To evaluate the bleaching efficacy and effects on enamel properties of experimental gels with carbamide peroxide (CP; 10%) or hydrogen peroxide (HP; 6%) containing calcium polyphosphate sub-microparticles (CaPPs). A total of 216 bovine tooth specimens were divided for microhardness and color analyses (n = 108) and block randomized into nine groups (n = 12): (G1) commercial CP (Whiteness Perfect, FGM; Brazil); (G2) experimental CP; (G3) CP-0.5%CaPPs; (G4) CP-1.5%CaPPs; (G5) commercial HP (Potenza Bianco, PHS; Brazil); (G6) experimental HP; (G7) HP-0.5%CaPPs; (G8) HP-1.5%CaPPs; (G9) artificial saliva. The gels' pH values were determined with a bench pH meter. Color (ΔE, ΔE00, ΔWID) and microhardness variation were evaluated before and after the therapy. Part of the specimens used for microhardness was submitted to the scanning electron microscopy (SEM) (n = 3) and energy-dispersive X-ray spectroscopy EDX (n = 3) analyses. Statistical analyses were performed in the R statistical software (α = 0.05). Linear mixed models for repeated measures in time were used to analyze microhardness and L* values. Generalized linear models were used to analyze the a*, b*, ΔE, ΔE00, and ΔWID, considering a group effect. The EDX data were analyzed using a one-way ANOVA with Tukey's test. The gels' pH remained over 6,0. All gels effectively bleached the specimens and did not differ significantly. When compared to the control group, the hardness was significantly lower in the G1, G2, G6, and G7 groups. The G3, G4, G5, and G8 groups did not differ significantly (p > 0.05). The incorporation of CaPPs in low-concentration whitening gels reduces its negative effects on microhardness without interfering with their bleaching efficacy.

Effect of saliva of patients with leukemia on surface hardness and roughness of enamel and dental composite resin during chemotherapy regimen: An – Invitro study

Background: Evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed into saliva collected from leukemia patient. Objective: To evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed on to saliva collected from 4 types of leukemia patient. Patients and Methods: 30 patients with 4 types of leukemia (Acute lymphoblastic leukemia ALL, Acute myeloid leukemia AML, Chronic lymphocytic leukemia CLL, and Chronic myeloid leukemia CML) were included for taking saliva separately. A total number of 50 enamel specimen and 50 of composite resin disk were prepared and randomly divided into 5 groups of enamel (1,2,3,4, and 5) and 5 groups of composite resin disk (A,B,C,D, and E), surface roughness and hardness were measured and data collected, group A and 1 were immersed in artificial saliva for 7 days as control, group B and 2 immersed into saliva collected from patient with ALL, group C and 3 immersed into saliva collected from patient with AML, group D and 4 immersed into saliva collected from patient with CLL and group E and 5 immersed into saliva collected from patient with CML all group for 7 days then surface roughness and hardness were measured data collected and analyzed and statistically significant regarded at p&lt;0.05. Results: In group A and 1 artificial saliva there were no significant effect on surface roughness and hardness of both enamel and composite resin disk, while surface roughness and hardness of enamel and composite resin significantly changed after immersing in saliva of ALL, AML, CLL, patients and surface roughness of composite resin highly significantly increased after immersing in saliva of CML patients. Conclusion: Saliva of ALL, AML, CLL, and CML seems to significantly changes in mechanical properties of enamel and composite, however saliva of CML highly significantly increase surface roughness of composite resin. Keywords: 4 types’ leukemia, chemotherapy, surface roughness and hardness, enamel, dental composite resin.

Effect of saliva of patients with leukemia on surface hardness and roughness of enamel and dental composite resin during chemotherapy regimen: An – Invitro study

Background: Evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed into saliva collected from leukemia patient.&#x0D; Objective: To evaluate the surface roughness and hardness of tooth enamel and dental resin composite restoration immersed on to saliva collected from 4 types of leukemia patient.&#x0D; Patients and Methods: 30 patients with 4 types of leukemia (Acute lymphoblastic leukemia ALL, Acute myeloid leukemia AML, Chronic lymphocytic leukemia CLL, and Chronic myeloid leukemia CML) were included for taking saliva separately. A total number of 50 enamel specimen and 50 of composite resin disk were prepared and randomly divided into 5 groups of enamel (1,2,3,4, and 5) and 5 groups of composite resin disk (A,B,C,D, and E), surface roughness and hardness were measured and data collected, group A and 1 were immersed in artificial saliva for 7 days as control, group B and 2 immersed into saliva collected from patient with ALL, group C and 3 immersed into saliva collected from patient with AML, group D and 4 immersed into saliva collected from patient with CLL and group E and 5 immersed into saliva collected from patient with CML all group for 7 days then surface roughness and hardness were measured data collected and analyzed and statistically significant regarded at p&lt;0.05.&#x0D; Results: In group A and 1 artificial saliva there were no significant effect on surface roughness and hardness of both enamel and composite resin disk, while surface roughness and hardness of enamel and composite resin significantly changed after immersing in saliva of ALL, AML, CLL, patients and surface roughness of composite resin highly significantly increased after immersing in saliva of CML patients.&#x0D; Conclusion: Saliva of ALL, AML, CLL, and CML seems to significantly changes in mechanical properties of enamel and composite, however saliva of CML highly significantly increase surface roughness of composite resin.

How mangabey molar form differs under routine vs. fallback hard-object feeding regimes

Background Components of diet known as fallback foods are argued to be critical in shaping primate dental anatomy. Such foods of low(er) nutritional quality are often non-preferred, mechanically challenging resources that species resort to during ecological crunch periods. An oft-cited example of the importance of dietary fallbacks in shaping primate anatomy is the grey-cheeked mangabey Lophocebus albigena. This species relies upon hard seeds only when softer, preferred resources are not available, a fact which has been linked to its thick dental enamel. Another mangabey species with thick enamel, the sooty mangabey Cercocebus atys, processes a mechanically challenging food year-round. That the two mangabey species are both thickly-enameled suggests that both fallback and routine consumption of hard foods are associated with the same anatomical feature, complicating interpretations of thick enamel in the fossil record. We anticipated that aspects of enamel other than its thickness might differ between Cercocebus atys and Lophocebus albigena. We hypothesized that to function adequately under a dietary regime of routine hard-object feeding, the molars of Cercocebus atys would be more fracture and wear resistant than those of Lophocebus albigena. Methods Here we investigated critical fracture loads, nanomechanical properties of enamel, and enamel decussation in Cercocebus atys and Lophocebus albigena. Molars of Cercopithecus, a genus not associated with hard-object feeding, were included for comparison. Critical loads were estimated using measurements from 2D µCT slices of upper and lower molars. Nanomechanical properties (by nanoindentation) and decussation of enamel prisms (by SEM-imaging) in trigon basins of one upper second molar per taxon were compared. Results Protocone and protoconid critical fracture loads were significantly greater in Cercocebus atys than Lophocebus albigena and greater in both than in Cercopithecus. Elastic modulus, hardness, and elasticity index in most regions of the crown were greater in Cercocebus atys than in the other two taxa, with the greatest difference in the outer enamel. All taxa had decussated enamel, but that of Cercocebus atys uniquely exhibited a bundle of transversely oriented prisms cervical to the radial enamel. Quantitative comparison of in-plane and out-of-plane prism angles suggests that decussation in trigon basin enamel is more complex in Cercocebus atys than it is in either Lophocebus albigena or Cercopithecus cephus. These findings suggest that Cercocebus atys molars are more fracture and wear resistant than those of Lophocebus albigena and Cercopithecus. Recognition of these differences between Cercocebus atys and Lophocebus albigena molars sharpens our understanding of associations between hard-object feeding and dental anatomy under conditions of routine vs. fallback hard-object feeding and provides a basis for dietary inference in fossil primates, including hominins.

Effects of 35% Versus 10% Carbamide Peroxide At-Home Bleaching Agents with or without MI Paste Plus on Enamel Properties

This study compared the effects of 35% with 10% carbamide peroxide (CP) home used bleaching agents on enamel color change, microhardness, and surface changes in association with MI paste plus (CPP -ACPF). Forty buccal and lingual enamel samples from twenty human third molars were prepared and divided into four groups (n=10). The groups were bleached for two weeks according to different bleaching regimens as follow; G1 bleached with 10%CP, G2 bleached with 35%CP, G3 bleached with a mixture of 10%CP and MI paste plus, and G4 bleached with a mixture of 35%CP and MI paste plus. Color change was recorded with a colorimeter before and after bleaching and total color differences (ΔE*) was calculated. Vickers microhardness test was recorded for all the samples before and after treatment. One sample from each group was evaluated for surface changes by scan electron microscopy (SEM). The data were analyzed with repeated measure of variance and student's t-test at p&lt;0.05. No significant difference in ΔE* was recorded among the four groups (p&gt;0.05). Significant reduction in enamel microhardness was only recorded for G2 (p=0.003). SEM for G3 and G4 showed obvious mineral deposition. Similar teeth color whitening can be resulted after two weeks of bleaching with both 10%CP and 35%CP when used as recommended by the manufacturer with and without the addition of MI paste plus. Using 35%CP decreased enamel microhardness significantly, whereas MI paste plus when mixed with both bleaching agents could compensate for the microhardness reduction.

Progress in the Application of Biomimetic Mineralization for Tooth Repair

The tooth, including enamel and dentin, is a prominent biomineral that is produced by the biomineralization of living organisms. Although the mechanical performance of the tooth is outstanding, caries easily develop in a complex oral environment. The analysis of the chemical composition and the relationship between the mechanical properties and the structure is of great importance in solving caries. In this review, the multilevel structure and mechanical properties of enamel and dentin are briefly introduced, along with caries formation and the limitations of clinical dental restoration. Furthermore, the progress of the application of a wide range of biomimetic strategies for tooth remineralization is highlighted, including the use of calcium phosphate ionic clusters to construct the mineralization front, ensuring the oriented epitaxial growth of enamel crystals and replicating the complex structure of the enamel. Moreover, compared with the current clinical treatment, in which the resin composite and glass ionomer cement are the main repair materials and the high incidence of secondary caries leads to imperfect restorations, the remineralization tactics could achieve excellent repair effectiveness in reconstructing the complicated structure, restoring mechanical strength and gaining permanent repair. A basic understanding of enamel and dentin, their potential for restoration, and hopeful prospects for tooth repair that can be applied in the clinical setting, not just in the laboratory, is provided by this review.

Influence of bleaching gels formulated with nano-sized sodium trimetaphosphate and fluoride on the physicochemical, mechanical, and morphological properties of dental enamel

ObjectivesTo evaluate in vitro the effects of sodium fluoride (F) and nano-sized sodium trimetaphosphate (TMPnano) added to a 35% hydrogen peroxide (H2O2) bleaching gel on the color alteration, enamel mechanical and morphological properties, and H2O2 transamelodentinal diffusion. Materials and MethodsBovine enamel/dentin discs (n = 180) were divided according to the bleaching gel: 35% H2O2 (HP); 35% H2O2 + 0.1% F (HP/F); 35% H2O2 + 1% TMPnano (HP/TMPnano); 35% H2O2 + 0.1% F + 1% TMPnano (HP/F/TMPnano) and 35% H2O2 + 2% calcium gluconate (HP/Ca). The gels were applied 3 times by 40 min; once each 7-day. The Commission Internationale de l'Eclairage (CIE) L*a*b* total color alteration (ΔE), color alteration by CIEDE2000 (ΔE00), whitening index (ΔWID), surface (SH) and cross-sectional hardness (ΔKHN), surface roughness (Ra), and transamelodentinal diffusion were determined. Enamel surfaces were evaluated by Scanning Electron Microscopy (SEM) and X-ray Dispersive Energy (EDX). Data were submitted to ANOVA, followed by the Student-Newman-Keuls test (p <0.05). ResultsΔE, ΔE00, and ΔWID were similar among the gels that promoted a bleaching effect after treatment (p <0.001). Mineral loss (SH and ΔKHN), Ra, and H2O2 diffusion were lower for HP/F/TMPnano; the HP and HP/Ca groups presented the highest values (p <0.001). For SEM/EDX, surface changes were observed in all bleached groups, but less intense with TMPnano. ConclusionsGels containing F/TMPnano do not interfere with the bleaching effect and reduce enamel demineralization, roughness, H2O2 diffusion, and morphological changes. Clinical RelevanceWhitening gels containing F/TMPnano can be used as a new strategy to increase safety and maintain clinical performance.

In vitro caries-preventive effect of a mineralization-promoting peptide combined with fluoride gel on sound primary teeth.

Mineralization-promoting peptide-3 (MPP3) is a new biomimetic remineralization agent. To assess the remineralization efficiency of MPP3, either alone or in combination with fluoride gel. The samples were divided into four groups: control, 1.23% fluoride gel, 10% MPP3 gel, and 1.23% fluoride gel + 10% MPP3. Following the application of remineralization agents (4 min), the samples remained in a pH-cycling model (37°C, 4 weeks). Microhardness, microcomputed tomography (micro-CT), polarized light microscopy (PLM), and field emission scanning electron microscopy (FE-SEM) analysis were conducted. RM-ANOVA, one-way ANOVA, and intraclass correlation coefficient (ICC) were used for statistical analysis, and a significance level of p < .05 was employed. Mineralization-promoting peptide 3 and fluoride gel + MPP3 increased the microhardness of the enamel compared with initial values in each group (p < .05). Mineralization-promoting peptide 3 successfully maintained the mineral density of enamel, although the cariogenic pH-cycling and PLM results indicated that the lesion depth (μm) was significantly lower in the fluoride gel + MPP3 group (27.0336 ± 12.53650) than in the control group (37.3907 ± 12.76002, p < .05). The combined use of MPP3 with fluoride gel enhanced the caries-protective and mineralization-promoting effects of fluoride. Mineralization-promoting peptide 3 may be a potential agent that can be employed to improve the physical properties of enamel.

The preventive/therapeutic effect of CO2 laser and MI Paste Plus® on intact and demineralized enamel against Streptococcus mutans (In Vitro Study)

BackgroundTo evaluate the preventive and therapeutic effects of CO2 laser and MI paste plus on intact and demineralized enamel surfaces and their impact on bacterial adhesion. Methods: 160 enamel slabs were prepared and randomly allocated into two main groups; sound and demineralized enamel (n = 80 per group), in which specimens were immersed in a demineralizing solution (50 mM acetic acid, pH 4.5) for 72 h at 37 °C. Each group was further divided into four subgroups (n = 20); the control (un treated surfaces), surfaces treated by CO2 laser, MI paste plus (Recaldent™, GC corporation/Germany), and those received a combination of CO2 and MI paste plus. Streptococcus Mutans biofilm was isolated, quantified, and then applied on treated enamel surfaces and incubated anaerobically for 24 h and then quantified by colony-forming unit (CFU). Meanwhile, surface changes were assessed by Vickers microhardness and Scanning Electron Microscope combined with Energy-Dispersive X-Ray Spectroscopy (SEM-EDX). Results: The combined use of CO2 laser followed by MI paste plus significantly (p < 0.000) enhanced surface microhardness of sound and demineralized enamel with a significant reduction in bacterial counts. However, each technique alone was beneficial as they exhibited higher microhardness with lower bacterial viability in comparison to the control. The treatment of demineralized enamel surfaces with MI paste significantly reduced the number of bacterial colonies with the presence of dispersed mineral deposits over the surface. ConclusionsThe combined use of CO2 laser and MI paste plus was effective as a preventive and/or therapeutic measures in enhancing surface properties of enamel and reducing the bacterial viability.

Maintenance of enamel properties after bleaching with high-concentrated hydrogen-peroxide gel containing calcium polyphosphate sub-microparticles.

To assessed the physical and chemical properties of human-enamel after treatment with an experimental bleaching gel containing 35%-hydrogen peroxide (HP) and calcium polyphosphate sub-microparticles (CaPP). Enamel/dentin specimens (4 × 4 × 3mm) were obtained (n = 120) and allocated to different groups: control (saliva only); experimental (HP35%); commercial (whiteness-HP-Maxx); CaPP0.5% (HP35% + CaPP0.5wt%); CaPP1.5% (HP35% + CaPP1.5wt%). Three sessions were performed. The specimens' color was assessed using a spectrophotometer and the color (ΔE/ΔE00) and bleaching index (ΔWID) determined. The surface roughness and microhardness were assessed with a roughness tester and Knoop indenter. Raman spectroscopy was performed to obtain the ratios between the areas under the 431, 580, and 1070cm-1 and the 960cm-1 bands (430:960, 580:960, 1070:960). Kruskal-Wallis and Dunn compared the color, Ra, and SMH data. The Raman data was analyzed with Kruskal-Wallis and Dunn (α = 5%). The ΔE, ΔE00, and ΔWID were similar among the bleached groups (p > 0.05). The roughness was not different between the groups (p > 0.05). After the 3rd session, CaPP0.5% had higher microhardness than the experimental (p < 0.05). The 1070:960 was higher in the experimental than in the CaPP1.5% and control (p < 0.05). In human enamel, CaPP did not alter the bleaching effectiveness or roughness, and additionally, CaPP-containing gels increased the microhardness and preserved the mineral content when compared to the experimental without CaPP. Experimental bleaching gels containing calcium polyphosphate sub-microparticles as a mineral source reduce the mineral content alteration and superficial microhardness reduction, known potential side effects of the in-office bleaching treatments.

Multi-modal and Correlative Microscopy Reveals Significant Changes in Composition, Structure and Biomechanical Properties in Dentine and Enamel Exposed to Common Acid Solutions.

Multi-modal and Correlative Microscopy Reveals Significant Changes in Composition, Structure and Biomechanical Properties in Dentine and Enamel Exposed to Common Acid Solutions.

Structural properties and electron spin resonance (ESR) dose estimations of fossil cow tooth enamel from Köşk Höyük, Turkey.

In this work, two cow teeth collected from the Niğde-Köşk Höyük excavation site in Turkey were studied for characterization and dosimetric purposes. Each tooth sample was prepared by applying mechanical and chemical methods to obtain the enamel fractions. To do this, mineralogical and elemental concentration properties of the tooth enamels were investigated by performing X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive X-ray measurements (SEM-EDX). It was found that the enamel structures contained a highly hydroxyapatite crystalline without any characteristic impurities. The dose response of the tooth enamels was determined by using the electron spin resonance (ESR) method. Absorbed radiation doses were calculated as (26.05 ± 0.15) Gy and (25.48 ± 0.18) Gy by the additive dose method using both natural radiation doses and artificial irradiation doses of the enamel samples. It is concluded that these samples could be used to reconstruct radiation doses. This result can be considered as a precursor for future ESR dosimetry/dating studies of other fossil teeth at this excavation site.

Antibacterial Properties of Borosilicate Enamel with Nanosized Zinc Oxide Particles

Antibacterial Properties of Borosilicate Enamel with Nanosized Zinc Oxide Particles

Communities of Fungi on Plates Coated with Antifouling Paint Modified by Nanoparticles

In the Sevastopol Bay (Black Sea), in the autumn period of 2021, fungal complexes were studied on plexiglass plates painted with anti-fouling enamel Bioplast-52 (control) and coatings based on it modified with nanoparticles (NP) Zn-FeO, ZnO and Fe-SiO. 16 species of fungi belonging to seven genera, five families, five orders, three classes of the Ascomycota division have been identified. The species composition was dominated by representatives of the genera Aspergillus (7 species) and Alternaria (4 species). The total number of fungal species isolated on substrates varied from 3 (with ZnO NP) to 8 (Bioplast-52) and with Zn-FeO NP), and by exposure time – from 3 (fourteenth day) to 14 species (sixty-first day). There were no representatives of the genera Aspergillus and Alternaria on the coating modified with Fe-CuO NP; only species of the genus Aspergillus were found on the coating with ZnO NP, the smallest number and number of fungal species were found on these coatings. Fe-CuO and ZnO nanoparticles enhanced the antifouling properties of Bioplast-52 enamel.

Maternal methylmercury exposure during early-life periods adversely affects mature enamel structure of offspring rats at human exposure levels: a concern for oral health.

Although there are many studies on the health effects of methylmercury (MeHg) toxicity during in utero and early development, little is known about its effects on mineralized tissues present in the oral cavity, such as enamel structure. Therefore, this study evaluated the effects of MeHg exposure on the physico-chemical, ultrastructural and functional properties of mature tooth enamel. Specifically, we studied offspring of mothers exposed to MeHg during the prenatal and postnatal periods which are the developmental stages associated with tooth enamel formation. Female rats were exposed to MeHg at a dose of 40 μg/kg/day for 42 days of pregnancy and lactation. The enamel of offspring was analyzed by (1) Fourier Transform Infrared Spectroscopy and Raman to assess physicochemical composition, (2) Scanning Electron Microscopy for ultrastructural evaluation, (3) Transmitted Polarizing Light Microscopy for analysis of the enamel extracellular matrix, and (4) resistance and hardness were evaluated by microhardness. The results showed that MeHg exposure during this sensitive enamel formation period induced changes in inorganic and organic content and enamel prisms ultrastructure alterations and disturbed the organic extracellular matrix due to a decreased enamel strength. These novel findings establish for the first time that maternal exposure to MeHg pre and postnatal promoted relevant changes in mature enamel of their offspring rats.