牙本质再矿化动力学和磷蛋白的作用研究

REMINERALIZATION OF DENTINE AND INFLUENCE OF PHOSVITIN ON KINETIC PROCESSES

牙本质再矿化过程是羟基磷灰石 (简称 :HAP)晶体的结晶过程。应用等组分晶体生长方法 ,研究了牙本质的结晶动力学过程 ,并探索了磷蛋白在矿化过程中的作用。实验条件是 :溶液温度θ=(3 7± 0 5 )℃ ;溶液酸度pH =7 0 0± 0 0 3 ;初始离子强度IS =0 15mol/L ;溶液的饱和度δ =5 2 3。研究结果表明如下 :(1)牙本质再矿化动力学过程可划分为初始反应、诱导反应及快速反应 3个阶段。第Ⅰ阶段揭示籽晶初始状态对于反应速率的影响 ;第Ⅱ阶段揭示二次成核的诱导时间 ;第Ⅲ阶段揭示二次成核后的晶体生长速率。 (2 )经EDTA和乙酸脱矿后的牙本质籽晶 ,其再矿化生长速率与脱矿时间相关 ,它表明HAP的结晶动力学特征与多种因素相关。 (3 )游离存在的磷蛋白 ,在矿化过程中的作用类似于无机杂质离子 ,抑制动力学过程的反应速率。

Dentine remineralization is a crystallization process of hydroxylapatite (HAP) crystal. The constant composition method is used to study the kinetics of remineralization on dentine crystal. The influence of phosvitin on the remineralization process of dentine crystals was also investigated. The experimental conditions are as follows: the solution temperature, θ=(37±0.5)°C; the solution acidity, pH=7±0.03; the initial ionic strength, IS=0.15 mol/L; the supersaturated solution, δ=5.23. The experimental results are as follows: (1) the procedure of dentine remineralization is divided into three steps; the initial reaction (step I), the induction reaction (step II) and the fast reaction (step III). In step I the influence of the initial seeds states on the reaction rate is revealed; in step II the induction time of the secondary nucleation is shown; and in step III the crystal growth rate after the secondary nucleation is revealed. (2) To the dentine seeds demineralized by EDTA and acetic acid, since the remineralization rate is related to its demineralization, it is demonstrated that the crystallization characteristic is influenced by many factors. (3) The phosvitin in free state plays an inhibitor role in the kinetic reaction rates during the dentine remineralization process.