Dental enamel-like hydroxyapatite whiskers with high crystallinity and homogeneous morphology were synthesized by a hydrothermal homogeneous precipitation method.The composition,crystallinity and morphology of prepare...Dental enamel-like hydroxyapatite whiskers with high crystallinity and homogeneous morphology were synthesized by a hydrothermal homogeneous precipitation method.The composition,crystallinity and morphology of prepared hydroxyapatite whiskers were characterized by Ⅹ-ray diffraction and scanning electron microscopy.The effects of urea and sorbitol on their morphology and composition were investigated.Homogeneous and well crystallized enamel-like hydroxyapatite whiskers with 1.17±0.08 μm in length and 84± 14 nm in width were obtained at 0.80 mol · L-1 urea and 0.26 mol · L-1 sorbitol.These hydroxyapatite whiskers may be close to nature hydroxyapatite dental enamel in terms of the morphology and composition,suggesting that they could have potential application as dental restorative materials in the field of stomatology.展开更多
Although aluminum itself was reported to prevent dental caries, previous in vitro studies reported that the aluminum level in the whole saliva of children was independent of caries prevalence. Purposes of this study w...Although aluminum itself was reported to prevent dental caries, previous in vitro studies reported that the aluminum level in the whole saliva of children was independent of caries prevalence. Purposes of this study were to compare the elution levels of aluminum and calcium from deciduous enamel into acidic artificial saliva, and determine whether the degree of aluminum elution reflects individual caries risk. One hundred and eleven extracted human deciduous teeth were collected. Concentrations of aluminum and calcium eluted from sound regions of enamel into artificial saliva (pH 6.2 or 5.5) were determined using atomic absorption spectrophotometry. One hundred and four and 108 available data samples were obtained for aluminum and calcium evaluation, respectively, and were compared based on the sex, tooth type, caries history, and the number of the donor’s carious teeth at each pH. Calcium elution was not affected by the sex;however, more aluminum was eluted from boys’ than from girls’ teeth at pH 5.5. The aluminum release depended on the tooth type, and was significantly higher in incisors than in molars at a pH of 5.5. In relation to the caries history, aluminum (at pH 5.5) and calcium (at pH 6.2) dissolved more from sound regions of the enamel of caries-experienced teeth than from the enamel of teeth without caries experience. Moreover, aluminum markedly dissolved from enamel in artificial saliva at both pH 6.2 and 5.5 when the donor had more carious teeth, regardless of the presence or absence of caries experience in the sampled teeth. There is a possibility that the rate of aluminum elution from enamel into acidic fluid reflects individual caries sensitivity.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
Microcrystalline structure changes of teeth enamel crystals during the artificial caries and synthetic saliva reminerlization were reported. Enamel samples were thinned by argon-ion-milling and examined by high-resolu...Microcrystalline structure changes of teeth enamel crystals during the artificial caries and synthetic saliva reminerlization were reported. Enamel samples were thinned by argon-ion-milling and examined by high-resolution transmitting electron microscope. The results revealed that the lattice dissolution of enamel hydroxyapatite started from central parts and grain boundaries of crystals, the former were often parallel to (1010) plane and advancing along the [0001] zone axis of crystals. The results also shown that synthetic saliva may reduce the quantity of bright contrast spots in lattice image for artificial carious crystals. In addition, some defects such as dislocations were found in grains, and they are believed to be related to the dissolution of lattice. Three kinds of structural weak sites revealed in crystals, i. e. (1)dislocations, (2) vacancies or impurities, and (3) grain boundaries.展开更多
背景:釉基质衍生物已经在临床上用于治疗严重的牙周炎,发现其可促进牙周组织修复、再生,但其中的机制还未阐明。目的:探讨釉基质衍生物对牙周膜干细胞分化和增殖的作用。方法:分离培养人牙周膜干细胞,检测其克隆形成率、表面抗原表达情...背景:釉基质衍生物已经在临床上用于治疗严重的牙周炎,发现其可促进牙周组织修复、再生,但其中的机制还未阐明。目的:探讨釉基质衍生物对牙周膜干细胞分化和增殖的作用。方法:分离培养人牙周膜干细胞,检测其克隆形成率、表面抗原表达情况,鉴定其多向分化潜能。将不同质量浓度的釉基质衍生物(20,50或100 mg/L)作用于牙周膜干细胞培养2,4周,用Trichrome和Von Kosa’s染色法检测牙周膜干细胞胶原合成及矿化结节形成情况,Real time RT-PCR方法检测成骨分化相关基因Ⅰ型胶原、骨钙素、RUX2的表达,MTT法和生长率法检测牙周膜干细胞的增殖情况。结果与结论:牙周膜干细胞呈梭形,其克隆形成率较牙周膜细胞高,表面抗原CD105,CD29,CD45,CD44的表达率分别为99.8%,99.7%,1.26%,98.8%,具备多向分化潜能。釉基质衍生物呈现一定的时间剂量效应关系促进牙周膜干细胞胶原合成及矿化结节形成,促进成骨分化相关基因Ⅰ型胶原、骨钙素、RUX2的表达,促进牙周膜干细胞的增殖,可能在牙周组织修复、再生中发挥作用。展开更多
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.2010066)the Natural Science Foundation of Heilongjiang Province(Grant No.E201006)the Key Scientific and Technological Projects of Heilongjiang Province(Grant No.GC10A107)
文摘Dental enamel-like hydroxyapatite whiskers with high crystallinity and homogeneous morphology were synthesized by a hydrothermal homogeneous precipitation method.The composition,crystallinity and morphology of prepared hydroxyapatite whiskers were characterized by Ⅹ-ray diffraction and scanning electron microscopy.The effects of urea and sorbitol on their morphology and composition were investigated.Homogeneous and well crystallized enamel-like hydroxyapatite whiskers with 1.17±0.08 μm in length and 84± 14 nm in width were obtained at 0.80 mol · L-1 urea and 0.26 mol · L-1 sorbitol.These hydroxyapatite whiskers may be close to nature hydroxyapatite dental enamel in terms of the morphology and composition,suggesting that they could have potential application as dental restorative materials in the field of stomatology.
文摘Although aluminum itself was reported to prevent dental caries, previous in vitro studies reported that the aluminum level in the whole saliva of children was independent of caries prevalence. Purposes of this study were to compare the elution levels of aluminum and calcium from deciduous enamel into acidic artificial saliva, and determine whether the degree of aluminum elution reflects individual caries risk. One hundred and eleven extracted human deciduous teeth were collected. Concentrations of aluminum and calcium eluted from sound regions of enamel into artificial saliva (pH 6.2 or 5.5) were determined using atomic absorption spectrophotometry. One hundred and four and 108 available data samples were obtained for aluminum and calcium evaluation, respectively, and were compared based on the sex, tooth type, caries history, and the number of the donor’s carious teeth at each pH. Calcium elution was not affected by the sex;however, more aluminum was eluted from boys’ than from girls’ teeth at pH 5.5. The aluminum release depended on the tooth type, and was significantly higher in incisors than in molars at a pH of 5.5. In relation to the caries history, aluminum (at pH 5.5) and calcium (at pH 6.2) dissolved more from sound regions of the enamel of caries-experienced teeth than from the enamel of teeth without caries experience. Moreover, aluminum markedly dissolved from enamel in artificial saliva at both pH 6.2 and 5.5 when the donor had more carious teeth, regardless of the presence or absence of caries experience in the sampled teeth. There is a possibility that the rate of aluminum elution from enamel into acidic fluid reflects individual caries sensitivity.
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Microcrystalline structure changes of teeth enamel crystals during the artificial caries and synthetic saliva reminerlization were reported. Enamel samples were thinned by argon-ion-milling and examined by high-resolution transmitting electron microscope. The results revealed that the lattice dissolution of enamel hydroxyapatite started from central parts and grain boundaries of crystals, the former were often parallel to (1010) plane and advancing along the [0001] zone axis of crystals. The results also shown that synthetic saliva may reduce the quantity of bright contrast spots in lattice image for artificial carious crystals. In addition, some defects such as dislocations were found in grains, and they are believed to be related to the dissolution of lattice. Three kinds of structural weak sites revealed in crystals, i. e. (1)dislocations, (2) vacancies or impurities, and (3) grain boundaries.
文摘背景:釉基质衍生物已经在临床上用于治疗严重的牙周炎,发现其可促进牙周组织修复、再生,但其中的机制还未阐明。目的:探讨釉基质衍生物对牙周膜干细胞分化和增殖的作用。方法:分离培养人牙周膜干细胞,检测其克隆形成率、表面抗原表达情况,鉴定其多向分化潜能。将不同质量浓度的釉基质衍生物(20,50或100 mg/L)作用于牙周膜干细胞培养2,4周,用Trichrome和Von Kosa’s染色法检测牙周膜干细胞胶原合成及矿化结节形成情况,Real time RT-PCR方法检测成骨分化相关基因Ⅰ型胶原、骨钙素、RUX2的表达,MTT法和生长率法检测牙周膜干细胞的增殖情况。结果与结论:牙周膜干细胞呈梭形,其克隆形成率较牙周膜细胞高,表面抗原CD105,CD29,CD45,CD44的表达率分别为99.8%,99.7%,1.26%,98.8%,具备多向分化潜能。釉基质衍生物呈现一定的时间剂量效应关系促进牙周膜干细胞胶原合成及矿化结节形成,促进成骨分化相关基因Ⅰ型胶原、骨钙素、RUX2的表达,促进牙周膜干细胞的增殖,可能在牙周组织修复、再生中发挥作用。
