Enamel demineralization,the formation of white spot lesions,is a common issue in clinical orthodontic treatment.The appearance of white spot lesions not only affects the texture and health of dental hard tissues but a...Enamel demineralization,the formation of white spot lesions,is a common issue in clinical orthodontic treatment.The appearance of white spot lesions not only affects the texture and health of dental hard tissues but also impacts the health and aesthetics of teeth after orthodontic treatment.The prevention,diagnosis,and treatment of white spot lesions that occur throughout the orthodontic treatment process involve multiple dental specialties.This expert consensus will focus on providing guiding opinions on the management and prevention of white spot lesions during orthodontic treatment,advocating for proactive prevention,early detection,timely treatment,scientific follow-up,and multidisciplinary management of white spot lesions throughout the orthodontic process,thereby maintaining the dental health of patients during orthodontic treatment.展开更多
Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especial...Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especially continuous wave(CW)THz near-field scanning microscopy(THz-SNOM)with its nanoscale reso⁃lution,can be promising in biomedical imaging.In addition,compared with traditional THz time-domain spec⁃troscopy(TDS),portable solid-state source as the emission has higher power and SNR,lower cost,and can ob⁃tain more precise imaging.In this study,we employ CW THz-SNOM to further break the resolution limitations of conventional THz imaging techniques and successfully achieve the near-field imaging of demineralized enamel at the nanoscale.We keenly observe that the near-field signal of the enamel significantly lowers as demineralization deepens,mainly due to the decrease in permittivity.This new approach offers valuable insights into the micro⁃scopic processes of enamel demineralization,laying the foundation for further research and treatment.展开更多
Enamelin （ENAM） has three putative phosphoserines （pSers） phosphorylated by a Golgi-associated secretory pathway kinase （FAM20C） based on their distinctive Ser-x-Glu （S-x-E） motifs. Fam2OC-knockout mice show s...Enamelin （ENAM） has three putative phosphoserines （pSers） phosphorylated by a Golgi-associated secretory pathway kinase （FAM20C） based on their distinctive Ser-x-Glu （S-x-E） motifs. Fam2OC-knockout mice show severe enamel defects similar to those in the Enam-knockout mice, implying an important role of the pSers in ENAM. To determine the role of pSer5s in ENAM, we characterized ENAMRgsc514 mice, in which Sers5 cannot be phosphorylated by FAM20C due to an E57〉Gs7 mutation in the S-x-E motif, The enamel microstructure of 4-week-old mice was examined by scanning electron microscopy. The teeth of 6-day-old mice were characterized by histology and immunohistochemistry. The protein lysates of the first lower molars of 4-day-old mice were analyzed by Western immunoblotting using antibodies against ENAM, ameloblastin and amelogenin. ENAMRgsc514 heterozygotes showed a disorganized enamel microstructure, while the homozygotes had no enamel on the dentin surface. The N-terminal fragments of ENAM in the heterozygotes were detained in the ameloblasts and localized in the mineralization front of enamel matrix, while those in the WT mice were secreted out of ameloblasts and distributed evenly in the outer 1/2 of enamel matrix. Surprisingly, the 15 kDa C-terminal fragments of ameloblastin were not detected in the molar lysates of the homozygotes. These results suggest that the phosphorylation of SerSS may be an essential posttranslational modification of ENAM and is required for the interaction with other enamel matrix molecules such as ameloblastin in mediating the structural organization of enamel matrix and protein-mineral interactions during enamel formation.展开更多
Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection,resistance to heat and abrasion,high hardness,hygiene and ease of cleaning.The typical ...Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection,resistance to heat and abrasion,high hardness,hygiene and ease of cleaning.The typical process to produce enameled steels is roughly divided into two stages:the first stage consists of a forming process to give the desired shape to a steel substrate,and the second stage consists of a firing process to bond enamel frits on the substrate.This firing process requires a high temperature above 800 °C,which may lead to austenitic transformation and severe thermal deformation of the steel substrate.The aim of this study is to develop a finite element analysis (FE analysis) technique to predict the mechanical and thermal deformations of the enameled steels during forming and any further enameling process,including firing.The FE analysis involves analyzing the strain history of the steel substrate,which comprises the stress and thickness distributions of the substrate and its deformed shape,and the high-temperature behavior of the enamel coating layer.The validity of the FE analysis is verified through the U-bending test and firing test with various numbers and positions of enamel coating layers on the substrate.The results reveal that the FE analysis results agree well with the experimental results with 8% error.展开更多
Numerical estimates of the components of yield strength of a high strength Fe-C-Mn-P-N-Si enameling steel were determined using empirical relationships between microstructure and yield strength. Results are reported f...Numerical estimates of the components of yield strength of a high strength Fe-C-Mn-P-N-Si enameling steel were determined using empirical relationships between microstructure and yield strength. Results are reported for both the hot rolled （HR） and cold rolled （CR） forms before and after simulating an enamel-fire anneal （EFA）. To determine the solubilities of alloying elements, thermodynamic calculations were performed in combination with the considerations of process conditions and the element diffusivities. The results show that the main solid solution strengtheners were the elements Mn, Si, and P, while the elements C and N were nearly completely tied up as precipitates. The yield strength reduction, due to the EFA, resulted primarily from an increase in grain size and a decrease in dislocation density, and the EFA appeared to have a negligible effect on the element solubilities.展开更多
During the production of the inner walls of ovens,pit defects were formed on the surface of the enamel layer that was enameled on the cold-rolled steel via electrostatic powder spraying and sintering.The paper elabora...During the production of the inner walls of ovens,pit defects were formed on the surface of the enamel layer that was enameled on the cold-rolled steel via electrostatic powder spraying and sintering.The paper elaborates on the microstructure and element distribution of the enamel-steel interface and the enamel layer.Optical microscopy,scanning electron microscopy,and energy-dispersive spectroscopy were adopted to investigate the microstructure of a longitudinal section of the defect,and the pit-forming causes were analyzed.The results show that rusty spots lead to pit defects.During high-temperature firing,there is an inadequate fusion and reaction between iron oxides of the rusty spots and the enamel glaze.The rusty spots are closely related to pretreatment process;thus,to avoid their occurrence,electrostatic powder spraying and sintering should be performed timely after forming,degreasing,and thorough drying of the metal sheets.展开更多
Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mine...Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a lowrotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.展开更多
The composition and production technology of the type of hot-rolled steel plate used in two-sided enameling were briefly described. The microstructure and mechanical properties before and after enameling were contrast...The composition and production technology of the type of hot-rolled steel plate used in two-sided enameling were briefly described. The microstructure and mechanical properties before and after enameling were contrastively investigated,and the precipitates in the samples were analyzed using transmission electron microscope and energy dispersive spectrometer. The results show the ferrite grain size of the steel plate after high-temperature enamel firing to be fine,with a large number of TiC and Ti;C;S;precipitates dispersed throughout the ferrite matrix. After two rounds of enamel firing at a temperature range of 800-890 ℃,its yield strength can still reach342 MPa. The results of a hydrogen permeation test show that the hydrogen storage properties of the steel plate are much better than those of ordinary structural carbon steel. A better bubble structure in the enamel layer can be obtained by this steel plate,with no fish-scale defects on the enameled steel-plate surface.展开更多
Objective: to investigate the effect of fluoride containing gel on preventing enamel demineralization and improving enamel lesion during orthodontic treatment. Methods: 60 patients were randomly divided into reference...Objective: to investigate the effect of fluoride containing gel on preventing enamel demineralization and improving enamel lesion during orthodontic treatment. Methods: 60 patients were randomly divided into reference group and study group (30 patients in each group) and received orthodontic treatment in our hospital from July 2020 to July 2021. After orthodontic treatment, the patients in the reference group were instructed to apply fluoride toothpaste. The patients in the research group were treated with fluoride gel smearing once a month on the basis of fluoride toothpaste. Then, the probability of enamel demineralization was compared and the impact on the degree of enamel damage was analyzed. Results: there was no significant difference between the clinical efficacy A and the study group (P>0.05). After 6 and 12 months of treatment, the incidence of enamel demineralization, enamel demineralization index, DD detection value, and the degree of enamel damage in the study group were lower than those in the reference group, and the teeth masticatory efficiency and tooth beauty scores were higher than those in the reference group, with statistical significance (P〈0.05). Conclusion: the application of fluoride containing gel in orthodontic treatment can not only effectively prevent the occurrence of enamel demineralization, but also reduce the degree of enamel damage, and promote the improvement of chewing efficiency and aesthetics of teeth. It is worth further application and promotion.展开更多
Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of appl...Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass （BG） before, after, and during 35% hydrogen peroxide （HP） bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups： distilled deionized water （DDW）, BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order： group HP〉 BG before HP, BG after HP〉 BG during HP〉DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.展开更多
This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal...This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal （Group LP）, disto-buccal （Group P）, mesio-lingual （Group NP） and disto-lingual （Group L） specimens. These four groups were treated using the standard cold-light bleaching procedure, a bleaching agent, a peroxide-free bleaching agent and cold-light, respectively. Before and after treatment, all specimens were analyzed by high-resolution, micro-area X-ray diffraction and scanning electron microscopy. Using a spectrometer, tooth color of all specimens was measured before and after treatment. The phase of the enamel crystals was identified as hydroxyapatite and carbonated hydroxyapatite. After treatment, specimens in Groups LP and P showed significantly weaker X-ray diffraction peaks, significant reduction in crystal size and crystallinity, significant increase in L~ but decrease in a＊ and b＊, and obvious alterations in the surface morphology. However, specimens in Groups NP and L did not show any significant changes. The cold-light bleaching treatment leads to demineralization in the enamel surface. The acidic peroxide-containing bleaching agent was the major cause of demineralization, whereas cold-light did not exhibit significant increase or decrease effect on this demineralization.展开更多
Aim The effect of Galla chinensis on de-/re-mineralization of advanced enamel lesions was investigated by using micro-CT in a prolonged in vitro experiment. Methodology Baseline mineral contents of sound enamels were ...Aim The effect of Galla chinensis on de-/re-mineralization of advanced enamel lesions was investigated by using micro-CT in a prolonged in vitro experiment. Methodology Baseline mineral contents of sound enamels were first analyzed. Then lesions were produced in an acidic buffer solution （2.2 mmol.L-1 Ca（NO3）2, 2.2 mmol-L1 KH2PO4, and pH=4.5） for 21 days, with thrice daily three-minute treatments, divided into four groups： Group A, 4 000 ppm crude aqueous extract of Galla chinensis （GCE）; Group B, 4 000 ppm gallic acid; Group C, 1 000 ppm F aq. （as NaF, positive control）; Group D, deionized water （negative control）. Next, the blocks were immersed in a remineralization solution （1.5 mmol.Lz CaC12, 0.9 mmol.L1 KH2PO4, 0.1 ppm F, and pH=7,0） for 200 days. Mineral loss （ML） in each region of interest （ROI） and integrated mineral loss （IML） of the lesions were calculated （comparing with baseline mineral content of sound enamel） at different time points. Results After 21 days demineralization, fluoride treatment showed a statistically significant demineralization-inhibiting effect among the four groups, and after 200 days of remineralization, mineral content recovery was ordered （lowest to highest） as A=C〈B〈D. Conclusion GCE could slow down the remineralization of enamel in the surface layer and thereby facilitate ion transport into the lesion body. The mechanism of Galla chinensis in enhancing the remineralization of dental caries is different from fluoride.展开更多
The Ti（C,N）precipitation and texture evolution in ultra-low carbon Ti-bearing enamel steel were studied to discover their correlation.Two different cooling paths of simulative coiling were adopted to gain different ...The Ti（C,N）precipitation and texture evolution in ultra-low carbon Ti-bearing enamel steel were studied to discover their correlation.Two different cooling paths of simulative coiling were adopted to gain different morphologies of Ti（C,N）precipitate in hot strips.It is found that the Ti（C,N）precipitate in hot strip using Path 2（put into asbestos box and air cooled）are finer and much more in quantity than that in hot strip using Path 1（held at 730℃ for 30min and furnace cooled）.The morphology of Ti（C,N）precipitate in hot strip has great effect on recrystallization texture in the subsequent cold-rolled annealed sheet.γ-fiber texture of strong recrystallization is gained in coldrolled and annealed sheet came from Path 1.On the contrary,in the one came from Path 2,theγ-fiber texture is weak.This may be due to the pinning force of numerous fine Ti（C,N）precipitate which retard the growth of preferential nucleated{111}orientated grains.Annealed steel sheets in the test came from both paths have excellent fishscale resistance.展开更多
The tooth enamel development gene, enamelin （ENAM）, showed evidence of positive selection during a genome-wide scan of human and primate DNA for signs of adaptive evolution. The current study examined the hypothesis...The tooth enamel development gene, enamelin （ENAM）, showed evidence of positive selection during a genome-wide scan of human and primate DNA for signs of adaptive evolution. The current study examined the hypothesis that a single-nucleotide polymorphism （SNP） C14625T （rs7671281） in the ENAM gene identified in the genome-wide scan is associated with a change in enamel phenotype. African Americans were selected as the target population, as they have been reported to have a target SNP frequency of approximately 50%, whereas non-Africans are predicted to have a 96% SNP frequency. Digital radiographs and DNA samples from 244 teeth in 133 subjects were analysed, and enamel thickness was assessed in relation to SNP status, controlling for age, sex, tooth number and crown length. Crown length was found to increase with molar number, and females were found to have thicker enamel. Teeth with larger crowns also had thicker enamel, and older subjects had thinner enamel. Linear regression and generalized estimating equations were used to investigate the relationship between enamel thickness of the mandibular molars and ENAM SNP status; enamel in subjects with the derived allele was significantly thinner （P= 0.040） when the results were controlled for sex, age, tooth number and crown length. The derived allele demonstrated a recessive effect on the phenotype. The data indicate that thinner dental enamel is associated with the derived ENAM genotype. This is the first direct evidence of a dental gene implicated in human adaptive evolution as having a phenotypic effect on an oral structure.展开更多
The Encouraging Novel Amelogenesis Models and Ex vivo cell Lines （ENAMEL） Development workshop was held on 23 June 2017 at the Bethesda headquarters of the National institute of Dental and Craniofacial Research （NI...The Encouraging Novel Amelogenesis Models and Ex vivo cell Lines （ENAMEL） Development workshop was held on 23 June 2017 at the Bethesda headquarters of the National institute of Dental and Craniofacial Research （NIDCR）. Discussion topics included model organisms, stem cells/cell lines, and tissues/3D cell culture/organoids. Scientists from a number of disciplines, representing institutions from across the United States, gathered to discuss advances in our understanding of enamel, as well as future directions for the field.展开更多
Deletion or mutation of dentin matrix protein 1 （DMP1） leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indir...Deletion or mutation of dentin matrix protein 1 （DMP1） leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate （Pi） or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmpl-null （Dmpl-/-）, Klotho-deficient （kl/kl）, Dmpl/Klotho-double-deficient （Dmpl-/-/kl/kl） and wild-type （WT） mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography （I^CT）, scanning electron microscopy （SEM）, histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmpl-/- （a low Pi level） or kl/kl（a high Pi level） mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice （a high Pi level） displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment （a high Pi level）.展开更多
Objective:This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths(μTBSs)of conventional and resin-modified glass ionomer cements(GICs/RMGICs).Methods:Forty-...Objective:This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths(μTBSs)of conventional and resin-modified glass ionomer cements(GICs/RMGICs).Methods:Forty-eight bovine incisors were prepared into rectangular blocks.Highly-polished labial enamel surfaces were either acid-etched,conditioned with liquids of cements,or not further treated(control).Subsequently,two matching pre-treated enamel surfaces were cemented together with one of four cements[two GICs:Fuji I(GC),Ketac Cem Easymix(3M ESPE);two RMGICs:Fuji Plus(GC),RelyX Luting(3M ESPE)]in preparation forμTBS tests.Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy(SEM).Results:Phosphoric acid etching significantly increased the enamelμTBS of GICs/RMGICs.Conditioning with the liquids of the cements produced significantly weaker or equivalent enamelμTBS compared to the control.Regardless of etching,RMGICs yielded stronger enamelμTBS than GICs.A visible hybrid layer was found at certain enamelcement interfaces of the etched enamels.Conclusions:Phosphoric acid etching significantly increased the enamelμTBSs of GICs/RMGICs.Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays,using GICs/RMGICs to improve the bond strengths.RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength.展开更多
Corrosion is one of the main causes of incidents occurred in hazardous liquid and gas transmission pipelines in the USA, resulting in a loss of over $12 billion per year. In this study, the corrosion resistance of pip...Corrosion is one of the main causes of incidents occurred in hazardous liquid and gas transmission pipelines in the USA, resulting in a loss of over $12 billion per year. In this study, the corrosion resistance of pipeline steel coated with five types of enamel was investigated in 3.5 wt% NaCl solution with linear polarization resistance and electrochemical impedance spectroscopy tests. Steel coupons were cut from API 5L X65 pipeline steel and coated with five types of enamels using the wet process. The microstructures of all enamel samples were examined by scanning electron microscopy. Experimental results indicate that all enamel coatings increase the corrosion resistance of pipeline steel, and pure enamel PE2, mixed enamels ME1 and ME2 have higher corrosion resistances than pure enamel PE1 and mixed enamel ME3.展开更多
Objective: To evaluate the effectiveness of herbal medicaments such as ginger, rosemary and honey on remineralization of initial enamel lesion.Methods: Demineralized human enamel specimens were measured for baseline s...Objective: To evaluate the effectiveness of herbal medicaments such as ginger, rosemary and honey on remineralization of initial enamel lesion.Methods: Demineralized human enamel specimens were measured for baseline surface microhardness and fluorescence methods. Ten specimens in each of four groups were used in this in vitro recycling study with the following treatments which applied three times a day: 1) sodium fluoride toothpaste(Ipana, Procter & Gamble, Turkey), 2) gingerhoney(Arifoglu Herbals, Anzer Honey, Turkey), 3) ginger-honey-chocolate(Bind Chocolate, Turkey), 4) rosemary oil(Arifoglu Herbals, Turkey). Treatment regimens of demineralization and remineralization cycle were applied for 21 days. The post-treatment data were obtained by measurements of surface microhardness and fluorescence methods.Data were statistically analyzed by ANOVA test with Tukey's honest significant difference test.Results: Enhanced remineralization was observed with several of the treatment systems including ginger + honey and rosemary. Significant differences between treatments were observed by microhardness and Fluore Cam fluorescence assesment, compared to the positive control group(Na F dentifrice). Significantly, greater remineralization was observed with the honey + ginger treatment regimen. No significant differences between groups were observed using the fluorescence assessment method, quantitative lightinduced fluorescence.Conclusions: Herbals(ginger, honey and rosemary) have enhanced remineralization of initial enamel lesion.展开更多
A promising duplex coating was prepared by microarc oxidation（MAO） and enameling processes onto polished Ti6A14V alloy. The TiO2 ceramic coating deposited by MAO was characterized and then combined with an enameling...A promising duplex coating was prepared by microarc oxidation（MAO） and enameling processes onto polished Ti6A14V alloy. The TiO2 ceramic coating deposited by MAO was characterized and then combined with an enameling treatment in order to improve the tribological and corrosion resistance of Ti6A14V alloy. The morphology, phase composition, and hardness of MAO and MAO/enameling-coated Ti6A14V alloy were evaluated by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and Vickers microhardness tester, respectively.The tribological performance was investigated using a ballon-disk tribometer. The corrosion resistance was studied using immersion tests and potentiodynamic polarization.Wear tests show that the enamel coating on the MAOcoated surface causes a reduction in the friction coefficient.Immersion tests demonstrate that the duplex coating is more effective in improving the corrosion resistance of Ti6A14V than the MAO coating especially at high temperature（80 ℃）. Potentiodynamic polarization curves reveal that the corrosion potential of the duplex coating increases by about 250 mV and the corrosion current density is slightly lower than that of the MAO coating. The duplex coating is superior to the stand-alone MAO coating in improving the tribological and corrosion behavior of Ti6A14V.展开更多
基金funded with National Key R&D Program of China(2022YFC2405904)National Natural Science Foundation of China(11932012,and 32171348).
文摘Enamel demineralization,the formation of white spot lesions,is a common issue in clinical orthodontic treatment.The appearance of white spot lesions not only affects the texture and health of dental hard tissues but also impacts the health and aesthetics of teeth after orthodontic treatment.The prevention,diagnosis,and treatment of white spot lesions that occur throughout the orthodontic treatment process involve multiple dental specialties.This expert consensus will focus on providing guiding opinions on the management and prevention of white spot lesions during orthodontic treatment,advocating for proactive prevention,early detection,timely treatment,scientific follow-up,and multidisciplinary management of white spot lesions throughout the orthodontic process,thereby maintaining the dental health of patients during orthodontic treatment.
基金Supported by the National Natural Science Foundation of China(61988102,62401113,92463308)。
文摘Enamel demineralization often occurs in the early stage of dental caries.Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries.Terahertz(THz)technolo⁃gy,especially continuous wave(CW)THz near-field scanning microscopy(THz-SNOM)with its nanoscale reso⁃lution,can be promising in biomedical imaging.In addition,compared with traditional THz time-domain spec⁃troscopy(TDS),portable solid-state source as the emission has higher power and SNR,lower cost,and can ob⁃tain more precise imaging.In this study,we employ CW THz-SNOM to further break the resolution limitations of conventional THz imaging techniques and successfully achieve the near-field imaging of demineralized enamel at the nanoscale.We keenly observe that the near-field signal of the enamel significantly lowers as demineralization deepens,mainly due to the decrease in permittivity.This new approach offers valuable insights into the micro⁃scopic processes of enamel demineralization,laying the foundation for further research and treatment.
基金supported by NIH grant DE026461start funding of Texas A&M University College of Dentistry
文摘Enamelin （ENAM） has three putative phosphoserines （pSers） phosphorylated by a Golgi-associated secretory pathway kinase （FAM20C） based on their distinctive Ser-x-Glu （S-x-E） motifs. Fam2OC-knockout mice show severe enamel defects similar to those in the Enam-knockout mice, implying an important role of the pSers in ENAM. To determine the role of pSer5s in ENAM, we characterized ENAMRgsc514 mice, in which Sers5 cannot be phosphorylated by FAM20C due to an E57〉Gs7 mutation in the S-x-E motif, The enamel microstructure of 4-week-old mice was examined by scanning electron microscopy. The teeth of 6-day-old mice were characterized by histology and immunohistochemistry. The protein lysates of the first lower molars of 4-day-old mice were analyzed by Western immunoblotting using antibodies against ENAM, ameloblastin and amelogenin. ENAMRgsc514 heterozygotes showed a disorganized enamel microstructure, while the homozygotes had no enamel on the dentin surface. The N-terminal fragments of ENAM in the heterozygotes were detained in the ameloblasts and localized in the mineralization front of enamel matrix, while those in the WT mice were secreted out of ameloblasts and distributed evenly in the outer 1/2 of enamel matrix. Surprisingly, the 15 kDa C-terminal fragments of ameloblastin were not detected in the molar lysates of the homozygotes. These results suggest that the phosphorylation of SerSS may be an essential posttranslational modification of ENAM and is required for the interaction with other enamel matrix molecules such as ameloblastin in mediating the structural organization of enamel matrix and protein-mineral interactions during enamel formation.
基金Project(NRF-2012R1A5A1048294)supported by the National Research Foundation of Korea(NRF)Grant funded by the Ministry of Education,Science and Technologythe LG Electronics
文摘Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection,resistance to heat and abrasion,high hardness,hygiene and ease of cleaning.The typical process to produce enameled steels is roughly divided into two stages:the first stage consists of a forming process to give the desired shape to a steel substrate,and the second stage consists of a firing process to bond enamel frits on the substrate.This firing process requires a high temperature above 800 °C,which may lead to austenitic transformation and severe thermal deformation of the steel substrate.The aim of this study is to develop a finite element analysis (FE analysis) technique to predict the mechanical and thermal deformations of the enameled steels during forming and any further enameling process,including firing.The FE analysis involves analyzing the strain history of the steel substrate,which comprises the stress and thickness distributions of the substrate and its deformed shape,and the high-temperature behavior of the enamel coating layer.The validity of the FE analysis is verified through the U-bending test and firing test with various numbers and positions of enamel coating layers on the substrate.The results reveal that the FE analysis results agree well with the experimental results with 8% error.
基金financially supported by AO Smith Corporate Technology Center,USA
文摘Numerical estimates of the components of yield strength of a high strength Fe-C-Mn-P-N-Si enameling steel were determined using empirical relationships between microstructure and yield strength. Results are reported for both the hot rolled （HR） and cold rolled （CR） forms before and after simulating an enamel-fire anneal （EFA）. To determine the solubilities of alloying elements, thermodynamic calculations were performed in combination with the considerations of process conditions and the element diffusivities. The results show that the main solid solution strengtheners were the elements Mn, Si, and P, while the elements C and N were nearly completely tied up as precipitates. The yield strength reduction, due to the EFA, resulted primarily from an increase in grain size and a decrease in dislocation density, and the EFA appeared to have a negligible effect on the element solubilities.
文摘During the production of the inner walls of ovens,pit defects were formed on the surface of the enamel layer that was enameled on the cold-rolled steel via electrostatic powder spraying and sintering.The paper elaborates on the microstructure and element distribution of the enamel-steel interface and the enamel layer.Optical microscopy,scanning electron microscopy,and energy-dispersive spectroscopy were adopted to investigate the microstructure of a longitudinal section of the defect,and the pit-forming causes were analyzed.The results show that rusty spots lead to pit defects.During high-temperature firing,there is an inadequate fusion and reaction between iron oxides of the rusty spots and the enamel glaze.The rusty spots are closely related to pretreatment process;thus,to avoid their occurrence,electrostatic powder spraying and sintering should be performed timely after forming,degreasing,and thorough drying of the metal sheets.
文摘Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a lowrotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.
文摘The composition and production technology of the type of hot-rolled steel plate used in two-sided enameling were briefly described. The microstructure and mechanical properties before and after enameling were contrastively investigated,and the precipitates in the samples were analyzed using transmission electron microscope and energy dispersive spectrometer. The results show the ferrite grain size of the steel plate after high-temperature enamel firing to be fine,with a large number of TiC and Ti;C;S;precipitates dispersed throughout the ferrite matrix. After two rounds of enamel firing at a temperature range of 800-890 ℃,its yield strength can still reach342 MPa. The results of a hydrogen permeation test show that the hydrogen storage properties of the steel plate are much better than those of ordinary structural carbon steel. A better bubble structure in the enamel layer can be obtained by this steel plate,with no fish-scale defects on the enameled steel-plate surface.
文摘Objective: to investigate the effect of fluoride containing gel on preventing enamel demineralization and improving enamel lesion during orthodontic treatment. Methods: 60 patients were randomly divided into reference group and study group (30 patients in each group) and received orthodontic treatment in our hospital from July 2020 to July 2021. After orthodontic treatment, the patients in the reference group were instructed to apply fluoride toothpaste. The patients in the research group were treated with fluoride gel smearing once a month on the basis of fluoride toothpaste. Then, the probability of enamel demineralization was compared and the impact on the degree of enamel damage was analyzed. Results: there was no significant difference between the clinical efficacy A and the study group (P>0.05). After 6 and 12 months of treatment, the incidence of enamel demineralization, enamel demineralization index, DD detection value, and the degree of enamel damage in the study group were lower than those in the reference group, and the teeth masticatory efficiency and tooth beauty scores were higher than those in the reference group, with statistical significance (P〈0.05). Conclusion: the application of fluoride containing gel in orthodontic treatment can not only effectively prevent the occurrence of enamel demineralization, but also reduce the degree of enamel damage, and promote the improvement of chewing efficiency and aesthetics of teeth. It is worth further application and promotion.
基金supported by the Research Fund from Science and Technology Department of Sichuan Province (No. 2009FZ0065)Key Project of the Science and Technology Department of Sichuan Province (No. 2011SZ0101)+1 种基金Doctoral Fund of Ministry of Education of China (No. 20120181120002)supported by Open Fund of State Key Laboratory of Oral Diseases, Sichuan University
文摘Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass （BG） before, after, and during 35% hydrogen peroxide （HP） bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups： distilled deionized water （DDW）, BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order： group HP〉 BG before HP, BG after HP〉 BG during HP〉DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.
文摘This in vitrostudy aims to evaluate the crystal and surface microstructure of dental enamel after cold-light bleaching treatment. Twelve sound human premolars were cross-split into four specimens, namely, mesio-buccal （Group LP）, disto-buccal （Group P）, mesio-lingual （Group NP） and disto-lingual （Group L） specimens. These four groups were treated using the standard cold-light bleaching procedure, a bleaching agent, a peroxide-free bleaching agent and cold-light, respectively. Before and after treatment, all specimens were analyzed by high-resolution, micro-area X-ray diffraction and scanning electron microscopy. Using a spectrometer, tooth color of all specimens was measured before and after treatment. The phase of the enamel crystals was identified as hydroxyapatite and carbonated hydroxyapatite. After treatment, specimens in Groups LP and P showed significantly weaker X-ray diffraction peaks, significant reduction in crystal size and crystallinity, significant increase in L~ but decrease in a＊ and b＊, and obvious alterations in the surface morphology. However, specimens in Groups NP and L did not show any significant changes. The cold-light bleaching treatment leads to demineralization in the enamel surface. The acidic peroxide-containing bleaching agent was the major cause of demineralization, whereas cold-light did not exhibit significant increase or decrease effect on this demineralization.
文摘Aim The effect of Galla chinensis on de-/re-mineralization of advanced enamel lesions was investigated by using micro-CT in a prolonged in vitro experiment. Methodology Baseline mineral contents of sound enamels were first analyzed. Then lesions were produced in an acidic buffer solution （2.2 mmol.L-1 Ca（NO3）2, 2.2 mmol-L1 KH2PO4, and pH=4.5） for 21 days, with thrice daily three-minute treatments, divided into four groups： Group A, 4 000 ppm crude aqueous extract of Galla chinensis （GCE）; Group B, 4 000 ppm gallic acid; Group C, 1 000 ppm F aq. （as NaF, positive control）; Group D, deionized water （negative control）. Next, the blocks were immersed in a remineralization solution （1.5 mmol.Lz CaC12, 0.9 mmol.L1 KH2PO4, 0.1 ppm F, and pH=7,0） for 200 days. Mineral loss （ML） in each region of interest （ROI） and integrated mineral loss （IML） of the lesions were calculated （comparing with baseline mineral content of sound enamel） at different time points. Results After 21 days demineralization, fluoride treatment showed a statistically significant demineralization-inhibiting effect among the four groups, and after 200 days of remineralization, mineral content recovery was ordered （lowest to highest） as A=C〈B〈D. Conclusion GCE could slow down the remineralization of enamel in the surface layer and thereby facilitate ion transport into the lesion body. The mechanism of Galla chinensis in enhancing the remineralization of dental caries is different from fluoride.
基金Sponsored by National Natural Science Foundation of China(50527402)National Basic Research Program(973Program)of China(2011CB606306-2)
文摘The Ti（C,N）precipitation and texture evolution in ultra-low carbon Ti-bearing enamel steel were studied to discover their correlation.Two different cooling paths of simulative coiling were adopted to gain different morphologies of Ti（C,N）precipitate in hot strips.It is found that the Ti（C,N）precipitate in hot strip using Path 2（put into asbestos box and air cooled）are finer and much more in quantity than that in hot strip using Path 1（held at 730℃ for 30min and furnace cooled）.The morphology of Ti（C,N）precipitate in hot strip has great effect on recrystallization texture in the subsequent cold-rolled annealed sheet.γ-fiber texture of strong recrystallization is gained in coldrolled and annealed sheet came from Path 1.On the contrary,in the one came from Path 2,theγ-fiber texture is weak.This may be due to the pinning force of numerous fine Ti（C,N）precipitate which retard the growth of preferential nucleated{111}orientated grains.Annealed steel sheets in the test came from both paths have excellent fishscale resistance.
基金supported by an NSF-DIG grant (DEB-0709660)an NIH grant (HD057974)the University of Washington Hack Estate
文摘The tooth enamel development gene, enamelin （ENAM）, showed evidence of positive selection during a genome-wide scan of human and primate DNA for signs of adaptive evolution. The current study examined the hypothesis that a single-nucleotide polymorphism （SNP） C14625T （rs7671281） in the ENAM gene identified in the genome-wide scan is associated with a change in enamel phenotype. African Americans were selected as the target population, as they have been reported to have a target SNP frequency of approximately 50%, whereas non-Africans are predicted to have a 96% SNP frequency. Digital radiographs and DNA samples from 244 teeth in 133 subjects were analysed, and enamel thickness was assessed in relation to SNP status, controlling for age, sex, tooth number and crown length. Crown length was found to increase with molar number, and females were found to have thicker enamel. Teeth with larger crowns also had thicker enamel, and older subjects had thinner enamel. Linear regression and generalized estimating equations were used to investigate the relationship between enamel thickness of the mandibular molars and ENAM SNP status; enamel in subjects with the derived allele was significantly thinner （P= 0.040） when the results were controlled for sex, age, tooth number and crown length. The derived allele demonstrated a recessive effect on the phenotype. The data indicate that thinner dental enamel is associated with the derived ENAM genotype. This is the first direct evidence of a dental gene implicated in human adaptive evolution as having a phenotypic effect on an oral structure.
文摘The Encouraging Novel Amelogenesis Models and Ex vivo cell Lines （ENAMEL） Development workshop was held on 23 June 2017 at the Bethesda headquarters of the National institute of Dental and Craniofacial Research （NIDCR）. Discussion topics included model organisms, stem cells/cell lines, and tissues/3D cell culture/organoids. Scientists from a number of disciplines, representing institutions from across the United States, gathered to discuss advances in our understanding of enamel, as well as future directions for the field.
基金supported by NIH grants Jian-Quan Feng (DE018486) and to Chun-Lin Qin (DE005092)State Key Laboratory of Oral Diseases Open Funding (SKLODOF2010-03) to Jian-Quan Feng
文摘Deletion or mutation of dentin matrix protein 1 （DMP1） leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate （Pi） or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmpl-null （Dmpl-/-）, Klotho-deficient （kl/kl）, Dmpl/Klotho-double-deficient （Dmpl-/-/kl/kl） and wild-type （WT） mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography （I^CT）, scanning electron microscopy （SEM）, histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmpl-/- （a low Pi level） or kl/kl（a high Pi level） mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice （a high Pi level） displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment （a high Pi level）.
基金Project supported by the National Natural Science Foundation of China(No.20973152)the Zhejiang Provincial Natural Science Foundation of China(No.Y2080045)
文摘Objective:This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths(μTBSs)of conventional and resin-modified glass ionomer cements(GICs/RMGICs).Methods:Forty-eight bovine incisors were prepared into rectangular blocks.Highly-polished labial enamel surfaces were either acid-etched,conditioned with liquids of cements,or not further treated(control).Subsequently,two matching pre-treated enamel surfaces were cemented together with one of four cements[two GICs:Fuji I(GC),Ketac Cem Easymix(3M ESPE);two RMGICs:Fuji Plus(GC),RelyX Luting(3M ESPE)]in preparation forμTBS tests.Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy(SEM).Results:Phosphoric acid etching significantly increased the enamelμTBS of GICs/RMGICs.Conditioning with the liquids of the cements produced significantly weaker or equivalent enamelμTBS compared to the control.Regardless of etching,RMGICs yielded stronger enamelμTBS than GICs.A visible hybrid layer was found at certain enamelcement interfaces of the etched enamels.Conclusions:Phosphoric acid etching significantly increased the enamelμTBSs of GICs/RMGICs.Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays,using GICs/RMGICs to improve the bond strengths.RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength.
基金financial support provided by the US Department of Transportation under Award No.DTPH5615HCAP10
文摘Corrosion is one of the main causes of incidents occurred in hazardous liquid and gas transmission pipelines in the USA, resulting in a loss of over $12 billion per year. In this study, the corrosion resistance of pipeline steel coated with five types of enamel was investigated in 3.5 wt% NaCl solution with linear polarization resistance and electrochemical impedance spectroscopy tests. Steel coupons were cut from API 5L X65 pipeline steel and coated with five types of enamels using the wet process. The microstructures of all enamel samples were examined by scanning electron microscopy. Experimental results indicate that all enamel coatings increase the corrosion resistance of pipeline steel, and pure enamel PE2, mixed enamels ME1 and ME2 have higher corrosion resistances than pure enamel PE1 and mixed enamel ME3.
文摘Objective: To evaluate the effectiveness of herbal medicaments such as ginger, rosemary and honey on remineralization of initial enamel lesion.Methods: Demineralized human enamel specimens were measured for baseline surface microhardness and fluorescence methods. Ten specimens in each of four groups were used in this in vitro recycling study with the following treatments which applied three times a day: 1) sodium fluoride toothpaste(Ipana, Procter & Gamble, Turkey), 2) gingerhoney(Arifoglu Herbals, Anzer Honey, Turkey), 3) ginger-honey-chocolate(Bind Chocolate, Turkey), 4) rosemary oil(Arifoglu Herbals, Turkey). Treatment regimens of demineralization and remineralization cycle were applied for 21 days. The post-treatment data were obtained by measurements of surface microhardness and fluorescence methods.Data were statistically analyzed by ANOVA test with Tukey's honest significant difference test.Results: Enhanced remineralization was observed with several of the treatment systems including ginger + honey and rosemary. Significant differences between treatments were observed by microhardness and Fluore Cam fluorescence assesment, compared to the positive control group(Na F dentifrice). Significantly, greater remineralization was observed with the honey + ginger treatment regimen. No significant differences between groups were observed using the fluorescence assessment method, quantitative lightinduced fluorescence.Conclusions: Herbals(ginger, honey and rosemary) have enhanced remineralization of initial enamel lesion.
基金financially supported by the Zhejiang Province Science and Technology Program (No. 2014C31126)
文摘A promising duplex coating was prepared by microarc oxidation（MAO） and enameling processes onto polished Ti6A14V alloy. The TiO2 ceramic coating deposited by MAO was characterized and then combined with an enameling treatment in order to improve the tribological and corrosion resistance of Ti6A14V alloy. The morphology, phase composition, and hardness of MAO and MAO/enameling-coated Ti6A14V alloy were evaluated by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and Vickers microhardness tester, respectively.The tribological performance was investigated using a ballon-disk tribometer. The corrosion resistance was studied using immersion tests and potentiodynamic polarization.Wear tests show that the enamel coating on the MAOcoated surface causes a reduction in the friction coefficient.Immersion tests demonstrate that the duplex coating is more effective in improving the corrosion resistance of Ti6A14V than the MAO coating especially at high temperature（80 ℃）. Potentiodynamic polarization curves reveal that the corrosion potential of the duplex coating increases by about 250 mV and the corrosion current density is slightly lower than that of the MAO coating. The duplex coating is superior to the stand-alone MAO coating in improving the tribological and corrosion behavior of Ti6A14V.
