背景:富含酪氨酸的牙釉质肽(TRAP)是发育釉质基质中主要的牙釉质消化产物。在我们先前的研究中,它已被证明可以促进脱矿牙釉质的再矿化。然而,尚未报道TRAP对釉质表面晶体生长的形态和纳米结构的影响的直接证据。这项研究旨在使用pH循环模型检查TRAP对早期牙釉质侵蚀中生长的磷酸钙晶体形态的影响。
方法:通过在37%磷酸中浸泡30秒,在人前磨牙中产生了侵蚀的病变。选择45个侵蚀的人前磨牙牙釉质块样品,随机分为3组:去离子水(DDW,阴性对照);100µg/mLTRAP,和2ppm氟化钠(NaF,阳性对照组)。14天,样本暴露于pH循环模型。利用扫描电子显微镜(SEM)和原子力显微镜(AFM)方法,表面形态,钙磷比,和搪瓷表面粗糙度进行了检查。利用X射线衍射(XRD)和傅里叶变换红外光谱(FT-IR)对晶体进行表征。
结果:pH循环后,与两个对照组相比,肽TRAP组的侵蚀牙釉质表面显示出大量新的,密集排列的棒状晶体,彼此平行,定期安排,形成有序的结构,晶体形态与天然釉质相似。晶体主要是羟基磷灰石(HA)。
结论:这项研究表明,肽TRAP可调节腐蚀牙釉质中羟基磷灰石的形成,新形成的晶体类似于天然牙釉质晶体,并促进牙釉质的再矿化,为牙釉质病变的再矿化治疗提供了一种有前途的生物材料。
BACKGROUND: Tyrosine-rich amelogenin peptide (TRAP) is the main amelogenin digestion product in the developmental enamel matrix. It has been shown to promote remineralization of demineralized enamel in our previous study. However, direct evidence of the effect of TRAP on the morphology and nanostructure of crystal growth on an enamel surface has not been reported. This study aimed to examine the effect of TRAP on the morphology of calcium phosphate crystals grown on early enamel erosion using a pH-cycling model.
METHODS: Eroded lesions were produced in human premolars by 30-second immersion in 37% phosphoric acid. Forty-five samples of eroded human premolar enamel blocks were selected and randomly divided into 3 groups: deionized water (DDW, negative control); 100 µg/mL TRAP, and 2 ppm sodium fluoride (NaF, positive control group). For 14 days, the specimens were exposed to a pH-cycling model. Using scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods, the surface morphology, calcium-phosphorus ratio, and enamel surface roughness were examined. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to assess crystal characteristics.
RESULTS: After pH-cycling, compared to the two control groups, the surface of the eroded enamel of the peptide TRAP group shows a large number of new, densely arranged rod-like crystals, parallel to each other, regularly arranged, forming an ordered structure, with crystal morphology similar to that of natural enamel. The crystals are mostly hydroxyapatite (HA).
CONCLUSIONS: This study demonstrates that the peptide TRAP modulates the formation of hydroxyapatite in eroded enamel and that the newly formed crystals resemble natural enamel crystals and promote the remineralization of enamel, providing a promising biomaterial for remineralization treatment of enamel lesions.