Chemical Composition Of Enamel Research Articles

Influence of maternal cholesterol-enriched diet on chemical composition of teeth enamel in offspring of mice.

Aim: To determine the chemical composition of the tooth enamel of two-day-old mice from hypercholesterolemic mothers by energy dispersive X-ray spectroscopy. Materials and Methods: Forty mature female mice were randomly assigned (n = 20/group) to either a standard chow vivarium diet (control group) or a cholesterol-enriched chow diet (experimental group). After fertilization, pregnancy and birth, on postnatal day 2, the incisor segments of 6 pups form each group were used for energy dispersive X-ray spectroscopy. Results: Influence of maternal hypercholesterolemic diet on tooth development and mineralization was examined, which revealed changes in enamel chemical composition. First, the results indicate the presence of seven elements (Na, Cl, Ca, P, Mg, S, Fe) in the enamel of both the hypercholesterolemic and normal offspring, but the content of element Ca2+ decreased, the content of elements P5+, Na+, Cl- tended to increase in pups from hypercholesterolemic mice. Second, the initial level of mineralization according to the atomic (%) Ca / P in hypercholesterolemic pups ratio was 1.26, comparing with normal pups where level of mineralization was 1.34. Taking into account that irreversible changes in the structure of the enamel were observed when the Ca / P ratio was below 1.33, we can suggest that the eruption of teeth with an imperfect structure could be because of maternal hypercholesterolemic diet. Conclusions: Results of this study suggest that hypercholesterolemic diet during gestation and lactation leads to altered enamel mineralization in mice because of changes in chemical composition and may link to the early childhood caries.

α-Mangostin and lawsone methyl ether in tooth gel synergistically increase its antimicrobial and antibiofilm formation effects in vitro

Objectivesα-Mangostin (α-MG) and lawsone methyl ether (LME) show antimicrobial and anti-biofilm activities. The objectives of this study were to develop a herbal tooth gel containing α-MG and LME plus fluoride and determine its antimicrobial, anti-biofilm formation, anti-cancer, anti-inflammatory, wound healing, and enamel microhardness effects.MethodsAntimicrobial assays against Streptococcus mutans, Porphyromonas gingivalis, and Candida albicans were performed. The microbes’ ultrastructural morphology was assessed using Transmission Electron Microscopy. The effect on microbial biofilm formation was tested by a broth microdilution. Cell viability was assessed with MTT assay. The anti-inflammatory effect was investigated by measuring inhibition of nitric oxide production. Enamel microhardness was measured via Vickers microhardness testing. The enamel chemical composition was investigated with Fourier Transform Spectrometer. The enamel surface morphology and fluoride content were examined by Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy.ResultsThe results show synergistic effects of α-MG and LME on antimicrobial activity and antibiofilm formation without cytotoxicity at a therapeutic dose. At a higher dose, the tooth gel inhibited proliferation of cancer cell line. Enamel microhardness was increased after brushing with the tooth gel plus fluoride. A large amount of fluoride was detected on the enamel surface.ConclusionThe tooth gel containing α-MG and LME synergized its antimicrobial activity and antibiofilm formation and inhibited oral cancer cell proliferation. Incorporating fluoride into the tooth gel increased enamel microhardness. Thus, the herbal tooth gel containing α-MG and LME plus fluoride may be useful for preventing dental caries and promoting oral health.

Red glass in Kunckel's Ars Vitraria Experimentalis: The importance of temperature

AbstractThe role of the melting conditions and furnaces used to the obtained final colors has always been a question raised when investigating formulations and recipes of historical glasses. The focus of the present work is the reproduction of three recipes of red enamel glass of the manuscript by Neri, L'arte vetraria (1612) following the translation and comments by Kunckel's in Ars Vitraria Experimentalis (1679). The reproductions include the production of each individual compound of the selected recipes following instructions, and the final glass production in electric and wood‐fire furnaces to assess the effect of different melting conditions. A multianalytical approach was used to fully characterize the produced samples allowing the study of the enamel chemical composition, color, crystals formations, and thermal properties. The results indicate that no significant color differences may be attributed to the melting conditions. However, it revealed that the samples produced in the electric furnace at 1200°C present a high crystallinity degree and the formation of white crystals at room temperature in a short period of time. The formation of crystals on glass is critical, and historically, to avoid it, these recipes must have been made at temperatures between 1050 and 1100°C.

Modification of dental enamel, dentin by an ultra-fast femtosecond laser irradiation: A systematic review

ObjectiveTo assess literature for the effectiveness and impact of femtosecond (fs) laser irradiation for surface processing of enamel and dentine. Materials and methodsThis systematic review followed PRISMA guidelines. Criteria for inclusion and exclusion were established, and searches undertaken in the PubMed/MEDLINE, Embase and, Scopus databases for articles published in English over a period of the last 25 years. In-vivo studies were excluded. Analysis explored the effects of varying laser parameters including the ablation threshold, ablation rate, relative ablation efficiency and the influence of laser processing parameters, such as the laser scanning speed, on purported surface changes and presumed thermal effects on dental enamel and dentin that arise directly as a result of fs laser irradiation. ResultsEleven articles that met the inclusion criteria reported that fs laser pulses can progressively remove (i.e., ablate) dental enamel and dentin with an acceptable precision and accuracy, with little or no observed thermal effects. These reported the use of an ultra-fast fs lasers employing different wavelengths, pulse durations and irradiation parameters, such as the output power and the pulse repetition rates. The chemical composition of enamel and dentin was found not to be significantly altered by an fs laser treatment. ConclusionSignificant efforts are still required to optimise fs laser parameters for precise and selective ablation of dental tissue and dentine to enable minimally invasive restorative procedures.

In vitro study on how antioxidant solutions affect enamel surface characteristics and bonding interface of ceramic laminate veneers luting after dental bleaching

PurposeThis in vitro study aimed to determine the effect of antioxidant solutions used after dental bleaching on the shear bond strength and adhesive interface sealing of ceramic laminate veneer luting. Additionally, effects on the enamel surface characteristics of hydrogen peroxide neutralization, surface energy, total free interaction energy, morphology, and chemical composition of enamel were assessed. Material and methodsTotal 127 bovine incisors were divided into experimental groups, according to the surface treatment (unbleached and bleached enamel), antioxidant types (control; 10% ascorbic acid and 10% α-tocopherol), and periods of luting of ceramic laminates (24 h and after 14 days). Shear bond strength was assessed using microtensile test before and after thermal cycling (5760 cycles, 5–55 °C) (n = 6). The sealing of the adhesive interface was assessed using a confocal laser scanning microscope (n = 3). Hydrogen peroxide neutralization analysis was performed using a spectrophotometer (n = 5). The surface energy and total free interaction energy (n = 10) were measured using an automatic goniometer, while enamel morphology and chemical composition were assessed by scanning eletron microscopy (n = 3). Shear bond strength and enamel surface properties data were subjected to ANOVA followed by Tukey's test (α = 0.05). Adhesive interface micrographs were evaluated by the inter-examiner Kappa test and subjected to Kruskal-Wallis and Dunn's tests (α = 0.05). ResultsIn general, thermal aging decreased the shear bond strength values of the luting agents to enamel (P < .05). The α-tocopherol solution was able to reverse the oxidizing effect from dental bleaching, increasing the shear bond strength values and preserving the integrity of the adhesive interface sealing (P < .05). Moreover, the α-tocopherol antioxidant agent promoted higher hydrogen peroxide neutralization after dental bleaching (P < .05). Dental bleaching influenced the enamel surface, decreasing the surface energy and total free interaction energy values (P < .05). Conclusionα-tocopherol was able to reverse the oxidizing effects of dental bleaching, improving the enamel surface properties, as well as the adhesion and interface sealing of ceramic laminate veneer restorations.

Correlation between chemical composition of enamel and oral fluid in patients with intact teeth and cervical pathology

Annotation. Cervical pathology of teeth is widespread and polyetiological, saliva plays an important role in its occurrence and progression. The aim of the study is to determine the chemical composition of oral fluid in patients with cervical caries, wedge-shaped defect, intact hard dental tissues; establish correlations between oral fluid and cervical enamel. In this regard 33 patients were divided depending on the condition of hard dental tissues and there were determined: Сa2+, РО43-, SO42-, Na+, К+, Al3+, Mg2+, Zn2+ – by spectrometric methods, Cl- – using a chloride-selective electrode pH-meter. The chemical composition of cervical enamel of 29 removed intact teeth and with cervical pathology was studied using a scanning electron microscope JSM-6490 LV with energy-dispersive X-ray microanalysis system INCA Penta FETx3. Molar coefficients were calculated as the ratio of the number of chemical analytes in the supernatant. Statistical analysis was performed using the computer program Statistica 8.0 (STA862D175437Q). Applied: analysis of variance (Welch test), correlation analysis (Pearson's parametric correlation method) based on the determination of the parametric Brave-Pearson coefficient (r) at p&lt;95%. The reliability of the obtained results was evaluated by Student's t-test and by Student's test using the Z-test (Fisher's z-test) at p≤0.05. There was no significant difference in the amount of chemical elements in saliva between the groups (p&gt;0.05) and significant differences were determined in K/Na (p=0.0258). There was correlation between chemical analyte content in the oral fluid and cervical tooth enamel: direct ‑ between Са2+ and РО43-, К+ and Cl-, К+ and Na+; inverse – between Са2+ and К+, Са2+ and Cl-, РО43- and К+, РО43- and Cl- (p&lt;0.0001). Correlation was identified: direct – between Ca/P and Ca/Mg, Ca/P and Ca/Cl, P/Ca and K/Na, Mg/Ca and Mg/P; inverse -‑between K/Na and Ca/P, K/Na and Ca/Cl, P/Ca and Ca/Cl, P/Ca and Ca/P (p≤0.05). Obtained results allowed to use Ca/Mg ratio as an indicator of enamel mineralization. We propose to use certain differences in correlation of chemical elements of oral fluid and tooth enamel to assess the mineral state of tooth enamel and control the effectiveness of preventive measures. Based on saliva parameters and microbiological indicators of dental biofilm the search for ways of preclinical diagnosis of cervical pathology is promising.

Comparative Evaluation of Influence of Nd:YAG Laser (1064 nm) and 980 nm Diode Laser on Enamel around Orthodontic Brackets: An In Vitro Study.

(1) Background: The prevention of demineralizing lesions at the enamel structure level continues to represent a challenge in daily dental practice. When bacteria influence the pH level, this will decrease below the threshold for remineralization and the dissociation of hydroxyapatite will occur with a high percentage of phosphate and calcium loss. These elements continue to be studied by many authors in order to obtain a working protocol that will lead to their stabilization at the level of the enamel structure, thus preventing the demineralization process. The aim of this study is to evaluate and compare the influence of two types of laser wavelengths on the surface morphology and mineral components of the enamel through an examination with scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX). (2) Methods: Thirty permanent human incisors extracted for periodontal reasons from patients aged 25–40 years old were selected for this study. Metallic brackets (SS Standard 022 Slot, OC Orthodontics, McMinnville, OR, 97128, USA) were bonded onto each tooth. The buccal surface was randomly assigned three sections: Section A—negative control (no treatment), section B—treated with 980 nm Gallium–Aluminum–Arsenide diode laser (a 300 µm optic fiber was used with 0.8 W output power, energy density of 5.33 J/mm2, in continuous mode, for 30 s, oriented perpendicularly to the enamel surface in contact mode) (KaVo GENTLEray 980 Diode Laser, Kaltenbach & Voigt GmbH, Biberach, Germany), and section C—treated with Nd:YAG laser (a 300 µm fiber was carried out at a 1 mm distance from the enamel surface with 0.75 W power, 75 mJ pulse energy, pulse repetition rate of 10 Hz, 5 J/mm2 fluency, average exposure time of 30 s, and water cooling assisted) (LIGHTWALKER AT S, M021-5AF/1 S, Fotona d.o.o, Ljubljana, Slovenia). The elements evaluated in this study were calcium (Ca), phosphate (P), oxygen (O), and carbon (C). A one-way analysis of variance, paired t-tests, and independent t-tests were carried out to evaluate the results using the SPSS 19 IBM Statistical package software for Microsoft. (3) Results: The evaluation of the data indicated that both wavelengths produced an increase in Ca wt% (for diode laser the mean of Ca wt% before irradiation was 21.06, while that after treatment reached 28.24; and for Nd:YAG laser, the mean of Ca wt% before irradiation was 21.31, while that after treatment reached 33.88); as well, the 980 nm diode laser decreased P wt% (from 17.20 before irradiation to 16.92 after irradiation) and the Nd:YAG laser increased P wt% (from 17.46 before irradiation to 18.28 after irradiation). These results showed a statistically significant difference at the p < 0.05 level. (4) Conclusions: It can be concluded that the best improvement of enamel chemical composition was obtained with Nd:YAG irradiation.

Correlation between dental enamel chemical composition and bracket debonding, comparing adhesive systems through a scanning electron microscope.

Literature reports indicate that during bracket removal there can be enamel damage. We compare the shear bond strength (SBS) and tooth enamel loss of four adhesive systems and identify the Ca/P ratio. Then a total of 20 premolars were divided into four groups of five each. After prophylaxis, photographs were taken at 35× with a scanning electron microscope (SEM) and analyzed with X-ray spectroscopy (EDS) at 250×. Brackets were bonded with Transbond™ MIP(G1), Transbond™ PLUS SEP(G2), Enlight(G3) and Stylus®(G4) adhesives, 24 h after were debonded with a Instron universal testing machine at 1 mm/min. All the brackets were photographed with the SEM. The amount of lost enamel was measured with AutoCad. All the results were measured with a significance level p < .05. The SBS general average at debonding was 7.94 ± 2.26 MPa, meanwhile the SBS for G1, G2, G3 and G4 was 9.38 ± 1.46, 6.28 ± 0.69, 9.08 ± 2.45 and 7.04 ± 2.64 MPa respectively. 90% of the samples had no enamel loss, 10% had enamel loss. Only two samples in G1 presented an enamel loss area of 0.34mm2 and 0.80mm2 respectively. From EDS analysis, the Ca/P ratio was 1.6 ± 0.05, 1.61 ± 0.03, 1.64 ± 0.83 and 1.59 ± 0.07 for G1, G2, G3 and G4 respectively; no statistically significant differences were found. We conclude that no association was found between the Ca/P ratio and enamel damage when brackets are removed. HIGHLIGHTS: Where enamel is lost, we observe fractures, steps, horizontal and vertical enamel loss. There is a loss of tooth enamel from 0.34 to 0.80 mm2 with Transbond PLUS SEP. Structural loss of enamel is almost inevitable during the separation of the bracket.

Vertebrate Taphonomy and Diagenesis: Implications of Structural and Compositional Alterations of Phosphate Biominerals

Biominerals are recorders of evolution and palaeoenvironments. Predation is one of the most frequent modes leading to the concentration of small vertebrates in fossil assemblages. Consumption by predators produces damages on bones and teeth from prey species, and one of the greatest challenges to taphonomists is differentiating original biological and secondary, geologically altered attributes of fossils. Excellent morphological preservation is often used to assume that the structure and composition of fossils are not modified. Nevertheless, during predation and fossilization, both the physical structure and chemical composition of enamel, dentine and bone are altered, the degree and extent of which varies from site to site, depending on the nature of the burial environment. A relationship between the surficial alterations and the compositional changes which take place during fossilization has yet to be established. Herein, I present a review of old and recent taphonomic studies that collectively reveal the wide diversity of microstructural and chemical changes that typically take place during fossilization of vertebrate remains, including common taphonomic biases and the challenges inherent to reconstructing the history of vertebrate fossil assemblages.

EXPERIMENTAL STUDY OF CHEMICAL COMPOSITION OF DENTAL ENAMEL DURING PROFESSIONAL WHITENING USING HYDROGEN PEROXIDE

Teeth whitening is a way to restore the natural colour of teeth with applying a chemical agent that oxidizes the organic pigments of the hard dental tissues. Teeth whitening has become one of the most frequently requested dental procedures among the population. The public demands whiter, more perfect smiles, and many teeth whitening options have been made in response. To assess the changes occurring in the hard dental tissues, and, in particular, in the enamel, it is necessary to study the chemical structure of the teeth and determine the number of elements in the enamel to predict the whitening procedure outcomes and make adjustments in post-procedural care. The aim of this study was to investigate the changes in the chemical composition of the dental enamel surface after the procedure of professional hygiene and the use of 35% hydrogen peroxide for teeth whitening as the main chemical component of the whitening system. To study the trace element composition of the dental enamel, the tooth surface was segmented into areas for microanalysis. The peculiarity consisted in that the studied areas differed from the right and left sides of the tooth, because the left side in the studied teeth was the control area, and the right side allowed us to compare and contrast the chemical component of enamel in each tooth separately, by comparing the findings. The results obtained have demonstrated that there is a change in the chemical composition of the enamel in the studied teeth. The change in chemical composition indicators significantly affects the change in clinical indicators, and the strength of clinical manifestations will depend on the features of functional and structural resistance of the dental enamel. We can state that changing in the number of elements can lead to increased sensitivity during the rehabilitation period throughout which the chemical composition of the dental enamel restores.

Mammalian enamel: A universal tissue and diverse source of inspiration

The natural armors and weapons of the animal kingdom are serving as inspiration in the development of next-generation engineering materials. In this pursuit, seldom considered are the variations in properties across taxa that have evolved to meet their unique functional demands. Here, teeth from six different mammalian species were acquired and categorized according to their bite force quotient (BFQ), which accounts for the allometric scaling between bite force and body size. Selected chemical, microstructural, and mechanical properties of the enamel were quantified across the enamel thickness using spectroscopy and indentation techniques. Results showed that the chemical composition of enamel was significantly (P < 0.05) different between the Low and High BFQ groups, whereas the apatite crystallinity was not. The enamel of all animals exhibited a spatial gradient in mechanical properties that was consistent when evaluated using a normalized framework. Although the elastic modulus, hardness and indentation brittleness were significantly lower in the High BFQ group, the fracture resistance of enamel was significantly higher in this group, potentially reflective of bite force requirements related to diet and predation. Enamel rod decussation was present in all teeth, but there were differences in specific microstructural features. Overall, these results highlight that the diversity of tooth enamel across species should be considered in the pursuit of nature-inspired structural materials. Statement of significanceNatural weapons are serving as inspiration in the development of next-generation engineering materials. Tooth enamel is a viable candidate, but variations in the structure and properties of enamel across taxa have not been explored. Here, teeth from six different mammalian species were categorized according to their bite force quotient (BFQ), and the enamel was compared in terms of selected chemical, microstructural, and mechanical properties. We show that specific aspects of the chemical composition and properties of the Low and High BFQ groups are unique, which appears reflective of bite forces associated with diet and predation. Overall, the results highlight that the diversity of tooth enamel across species should be considered in the pursuit of nature-inspired structural materials.

Effect of Er:YAG Laser Irradiation and Acidulated Phosphate Fluoride Therapy on Re-Mineralization of White Spot Lesions.

Statement of the Problem: Studies on the efficacy of erbium laser for enhancement of enamel resistance to acid attacks and its effects on fluoride uptake by the enamel are limited.Purpose: This study sought to assess and compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation and application of acidulated phosphate fluoride (APF) gel (alone and in combination) on remineralization of artificial white spot lesions (WSLs).Materials and Method: This in vitro, experimental study evaluated 90 buccal and lingual slabs of extracted human premolars. The specimens underwent pH cycling to induce WSLs. They were then randomly divided into 6 groups of caries-free positive control (c+), negative control with WSLs (ws), 1.23% APF gel applied on the enamel (F), Er:YAG laser irradiation (80 mJ, 10 Hz, and 8 J/cm2) of enamel (L), APF gel application followed by laser irradiation (FL), and laser irradiation followed by fluoride gel application (LF). The fluoride ion content of specimens was measured before and after the intervention using a potentiometer. Data were analyzed by ANOVA (p< 0.05).Results: APF gel application before/after laser irradiation maximally increased the fluoride uptake by the enamel (p= 0.000). Application of APF gel in group F and laser irradiation in group L increased fluoride uptake by the enamel, compared with groups 1 and 2 (p= 0.000). Laser- treated (L) and APF-treated (F) groups had no significant difference in this respect (p= 0.945). Maximum fluoride concentration was noted in combined laser and fluoride groups (FL=332.07ppm and LF=341.27ppm) with no significant difference between the two (p= 1.000).Conclusion: Er:YAG laser irradiation changes the chemical composition of enamel and probably promote its remineralization, especially when combined with APF gel application, which highlights its cariostatic potential.

Method for predicting the development of cervical caries and teeth with wedge-shaped defect in young people

Annotation. Significant prevalence of cervical caries and teeth with wedge-shaped defect is the reason for the search for ways to predict their development that is possible only with an individual approach. The purpose of the study is to design and test the method for predicting the development of cervical caries and teeth with wedge-shaped defect in young people based on the results of determining the chemical composition of enamel, dentin and oral fluid. The chemical composition of the enamel and dentin of 29 teeth was examined using JSM-6490 LV focused beam electron microscope (scanning). We determined the content of the chemical elements in the oral fluid of 33 patients: Сa2+, РО43-, SO42 - by spectrophotometric method, Na+, К+, Al3+ by atomic emission spectrometry, Mg2+, Zn2+ by atomic absorption spectrometry, Cl- using chloride selective electrode of pH meter. Statistical analysis was performed using the computer program Statistica 8.0 (STA862D175437Q). Analysis of variance (Welch test), Pearson's parametric correlation method (Brave-Pearson coefficient (r)) was used. The reliability of the obtained results was evaluated by Student's t-test, the correlation between the indicators – by Student's test using the Z-test (Fisher's z-test) at p≤0.05. It was determined that the values of the К/Na+Са/Сl coefficient in enamel (equator, cervical region), dentin (cervical region), oral fluid significantly differed depending on the state of hard dental tissues (p≤0.05). Direct correlation of moderate and high strength was revealed between Са/Р and К/Na+Са/Сl – coefficients in cervical enamel and saliva (p≤0.0001). Obtained results became the basis for the development of the method for individual prediction of the development of cervical pathology in young people. Its approbation was carried out in 43 patients, its effectiveness was assessed a year later. With the values of the К/Na+Са/Сl 2 coefficient and lower we diagnosed the absence of the risk of developing cervical caries and wedge-shaped defect, from 2.1 to 5.3 the risk of developing cervical caries was diagnosed, from 5.4 and more the risk of developing wedge-shaped defect was found out. It was confirmed that the proposed method is informative (the prediction accuracy reaches 83,7%), its non-invasiveness is the basis for widespread use. We consider the search for the ways to predict particularly the development of teeth cervical pathology based on the parameters of the oral fluid and dental biofilm to be promising.

Quantitative light-induced fluorescence as a potential tool for detection of enamel chemical composition.

Little is known about how the chemical composition of enamel affects the optical properties of teeth, but advances in technology allow this to be studied using white-light and fluorescent images. This study aimed to identify the variation in enamel chemical composition that may affect tooth optical properties, such as tooth color and autofluorescence. Sixty-one specimens of extracted human molars were prepared. Raman spectrometry was used to assess chemical composition of enamel, and tooth color, and autofluorescence from enamel were evaluated by quantitative light-induced fluorescence (QLF) images. Pearson correlation and multiple linear regression analyses were used. Enamel fluorescence was related to enamel composition rather than tooth color. The b* value from the fluorescence image had a moderate correlation with crystallinity (full-width at half-maximum: r = -0.433, p < 0.001) and laser-induced fluorescence intensity (r = 0.450, p < 0.001) from Raman spectroscopy. In multiple linear regression analysis, the chemical composition of the tooth had a significant effect on the b* value from the fluorescent image (R2 = 0.433, p < 0.001). In contrast, tooth color values (L*, a*, and b*) were not correlated with chemical composition. The present study revealed that enamel autofluorescence in QLF was related to chemical composition of the enamel, particularly the inorganic‒organic interface. While enamel chemical composition can be detected only in a laboratory environment, enamel fluorescence by QLF may enable estimation in a dental clinic, which has implications for the field of tooth bleaching or esthetic restorative materials.

Differences in the Natural Enamel Surface and Acquired Enamel Pellicle following Exposure to Citric or Hydrochloric Acid

Objectives: The aim of this study was to investigate variations in the interaction between enamel, that is, the acquired enamel pellicle (AEP) and citric or hydrochloric acid. Materials and Methods: A 24-h AEP was formed on natural enamel specimens (n = 40) from pooled whole mouth human saliva. Samples were randomly allocated to citric (0.3%, pH 3.2) or hydrochloric (HCl) acid (0.01 M, pH 2.38) exposure for 30 or 300 s. The total protein concentration (TPC), and phosphorous and calcium concentrations of the pellicle were determined before and after acid exposure, and again after re-immersion in saliva. Surface roughness and tandem scanning confocal microscopy imaging were used to assess enamel changes. Results: After 300 s of citric acid exposure, the mean ± SD TPC reduced from 5.1 ± 1.1 to 3.5 ± 1.1 mg/mL (p < 0.05). In contrast, after 300 s of HCl exposure, the mean TPC did not reduce significantly from baseline (6.6 ± 1.1 to 5.7 ± 0.7 mg/mL) but was significantly reduced in the reformed pellicle to 4.9 ± 1.2 mg/mL (p < 0.001). This reduction occurred after significant release of calcium and phosphorous from the enamel surface (p < 0.001). Thirty seconds of exposure to either acid had no obvious effect on the AEP. The surface roughness of the enamel decreased after acid exposure but no differences between groups was observed. Conclusions: These findings indicate that citric acid interacted with proteins in the AEP upon contact, offering enamel protection. In contrast, HCl appeared to bypass the pellicle, and reduced protein was observed only after changes in the enamel chemical composition.

Ultrastructural and Chemical Composition of Dentin and Enamel in Lab Animals.

Statement of the Problem:Human tooth is clinically the most appropriate material that can be used for in-vitro dental research. However, there are limitations and drawbacks for using human teeth. Therefore, alternatives to samples of human teeth for dental studies are necessary. Purpose: This study purposed to evaluate and compare the microstructure and chemical composition of enamel and dentin of teeth in some lab animals. Materials and Method: In this experimental study, teeth of mouse, rabbit, guinea pig, dog, cat, and sheep were used. Scanning electron microscope observations and X-ray diffraction analysis were performed on samples. Results: This study revealed resemblance in general structure of dentin and enamel between mentioned animals and human. The minimum mean of dentinal tubules diameter is found in guinea pig (0.5µ), while the highest is in cat (1.5µ). Also the lowest and the highest mean intertubular distance was measured respectively in guinea pig (3µ) and sheep (4.8µ) and the maximum and minimum mean diameter of rods was measured in rabbit (6.6µ) and guinea pig (1.5µ), respectively. Conclusion:The recorded details and the measured values indicate great resemblance between dog and human dentin and enamel. Cat is in the second place for dentinal studies; sheep and guinea pig have the least resemblance to human within the scope of the reviewed criteria.

Evaluation of Rremineralization Capacity of Non-fluoride Home Products

The aims of the study were to characterize enamel, dentine and cementum surface aspect after using non-fluoride remineralization toothpastes containing calcium carbonate and calcium glycerophosphate by SEM evaluation, to determine chemical composition of enamel, dentin and cement after remineralization products application by EDX assessment, and to compare the remineralization capacity of the tested products. Ten extracted teeth having no dental caries, erosive or wear lesions were selected for the study. The teeth were split bucco-lingually and mesio-distally in four pieces. A free window of enamel, dentine, and cementum (4X4 mm) in the cervical area of the slices was preserved. In control group the slices were subjected to a artificial caries lesion formation. In study groups EcoBio� (President Company), Bio-natural (Dentissimo, Swiss Biodent), and Arthrodont Cassic (Pierre Fabre Oral Care) toothpastes were applied two times a day, for 3 minutes during caries lesion formation. The surface topography has been analyzed using a scanning electron microscope and the quantitative and qualitative chemical composition has been evaluated using an EDX detector. Interprismatic and intraprismatic mineral loss is clearly visible at higher magnification in enamel samples in control group. Some areas of demineralization are still present, and also small areas of extern deposits are visible on enamel, dentine and cementum samples in the groups were tested products were applied. All the tested toothpastes increased calcium and phosphorous ion concentrations in enamel, dentine and cementum. The highest remineralization effect was recorded in enamel by Dentissiomo, followed by Arthrodent and EcoBio toothpastes. In dentine and cementum the highest remineralization effect was registered by Arthrodent, followed by Dentissiomo and EcoBio toothpastes.

Chemical composition and roughness of enamel and composite after bleaching, acidic beverages and toothbrushing.

BackgroundIn this study was assessed the surface roughness and chemical composition of tooth enamel and composite resin after bleaching treatment, immersion in acidic beverages, and simulated toothbrushing.Material and MethodsOne hundred and twenty dental blocks (10 x 10 x 3 mm) were randomly assigned (n = 10) according to surface treatment [none (N), bleaching (B), toothbrushing (T), and B+T] and storage medium [saliva (S), whiskey (W), and orange juice (O)]: experimental groups - N+S, N+W, N+O, B+S, B+W, B+O, S+T, W+T, O+T, B+S+T, B+W+T, and B+O+T. Two bleaching sessions were conducted using 38% hydrogen peroxide (3 applications). Surface roughness was measured using a roughness tester and composition was determined by micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) before and after treatments. Calcium/phosphorus (Ca/P) ratio in enamel and silica (Si) content in composite were evaluated. Data were statistically analyzed by ANOVA and Tukey’s test (α = 0.05).ResultsOverall, increased values of surface roughness for enamel and composite were observed mainly after immersion in orange juice and bleaching/toothbrushing association. Moreover, this association and immersion in whiskey resulted in lower Ca/P ratio and after aging methods, bleached and bleached/toothbrushed groups showed decreased in Ca/P ratio compared to initial values. All groups showed Si content decrease at the end, except the group without surface treatment and immersed in saliva, and bleaching followed by immersion in orange juice and toothbrushing caused the highest Si reduction.ConclusionsBleaching and toothbrushing combination strengthened the effects caused by acidic drinks on roughness and chemical composition of enamel and composite. Key words:Tooth bleaching, toothbrushing, physical properties, chemical properties.

XRMA analysis and X-ray diffraction analysis of dental enamel from human permanent teeth exposed to hydrogen peroxide of varying pH

BackgroundThis in vitroinvestigation shows how 3.3% H2O2, at different pH-values affects the enamel.Material and MethodsA number of fifteen human premolars were used. The enamel of the coronal half in six of the teeth, were exposed by H2O2. Nine teeth were prepared to enamel powder. The enamel was exposed to 3.3% H2O2, at six different pH-values (pH range 4.5 - 7.0). Analyses of the topography of enamel performed by scanning electron microscope (SEM) and the chemical composition of enamel by X-ray microanalysis (XRMA). X-ray powder diffraction (XRD) analysed the crystallinity in enamel powder.ResultsThe exposure to H2O2 at pH<5.5 resulted in a rougher topography of the enamel, according to the SEM studies. The XRMA analysis revealed a increase in the ratio of Ca:C. Exposure to H2O2 at pH>5.5 resulted in a decrease of O in the exposed enamel, and changes in C:P, Ca:C, Ca:P and Ca:O were observed. The H2O22 did not affect the unit cell parameters, but the signal-to-noise level was increased for slightly acidic or neutral solutions. The unit cell parameters decreased in the acidic solutions.ConclusionsThe exposure to H2O2 at varying pH values affect the enamel with two different mechanisms. One effect is the oxidation of the organic or bioorganic matter in the hydroxyapatite matrix, due to the use of 3.3% H2O2. The other effect is due to the current pH of the H2O2, since the structure of the hydroxyapatite starts to erode when the pH<5.5. Key words:Dental Enamel, Tooth Bleaching Agents, Hydrogen Peroxide, Scanning Electron Microscopy, X-ray diffraction.

Effect of 2.94 µm Er: YAG laser on the chemical composition of hard tissues.

The aim was to investigate the effect of the Er-YAG laser radiation on morphology and chemical composition of enamel, dentin, and bone. The specimens of the three groups were irradiated with a very long pulse mode (VLP) of 2.94 µm Er-YAG laser with 100 mJ pulse energy and energy density of 8.42 J/ for 30 s, at a repetition rate of 15 Hz. The organic and inorganic content of the samples were investigated by Fourier Transforms Infrared spectroscopy (FTIR). The morphological characteristics were investigated with scanning electron microscopy (SEM) and elemental analysis (calcium and phosphorus) with energy-dispersive X-ray spectroscopy (EDX). FTIR data were analyzed with a One-Way ANCOVA test and EDX data with the independent sample t-test. Following the laser radiation, FTIR showed a significant decrease in the organic content of all tissues. The weight percentage (wt %) calcium content of dentin and bone increased significantly following irradiation with a p-value of .002 for both tissues, but the wt % of phosphorus content was not influenced significantly. The morphological alterations expressed signs of fusion in all the samples.