氟磷灰石晶体膜对变异链球菌早期粘附和生物膜形成的作用

目的:研究牙本质表面再生氟磷灰石晶体膜(Fluorapatite crystal film,FACF)对变异链球菌(S.mutans)早期粘附和生物膜形成的作用。方法:近生理条件下(37℃,1 atm,pH 6.0~7.4),在牙本质表面沉积FACF,并将牙本质、羟基磷灰石(hydroxyapatite,HA)和氟磷灰石(fluorapatite,FA)样本作为对照组,SEM观察表面形貌。激光共聚焦显微镜(CLSM)和SEM观察牙本质和FACF表面S.mutans的早期粘附情况。HA、FA、牙本质及FACF表面培养S.mutans生物膜,CLSM观察并计算生物膜量。结果:FACF厚5~10μm,晶体呈标准的六棱柱样,排列规则紧密,直径0.5~1.0μm。FACF表面S.mutans粘附量显著少于牙本质(P<0.05),单位面积生物膜量显著低于HA、FA及牙本质(P<0.05),且阻挡了S.mutans向牙本质小管内生长。结论:在近生理条件下,可在牙本质表面再生出厚5~10μm的FA有序致密晶体膜,该层晶体结构可减少S.mutans的初期粘附及生物膜的形成,并对S.mutans向牙本质小管内生长起到物理屏障作用。

Effects of Regenerated Fluorapatite Crystal Film on Early Adhesion and Biofilm Growth of Streptococcus Mutans

Objective:To investigate the effects of fluorapatite crystal film(FACF)on early adhesion and biofilm growth of Streptococcus mutans(S.mutans).Methods:Under near-physiological conditions(37℃,1 atm,pH 6.0-7.4),FACF was regenerated on the surface of exposed dentin.The dentin,hydroxyapatite(HA),and FA were prepared as the control groups.SEM was used to observe the surface morphology of the samples.The adhesion of S.mutans on the surface of dentin and FACF was observed with confocal laser scanning microscope(CLSM)and SEM.The S.mutans biofilm was cultured on the surfaces of HA,FA,dentin,and FACF,which was observed by CLSM.The amount of biofilm was calculated.Results:The thickness of FACF was about 5-10μm.The crystal was standard six-prism shape with a diameter of 0.5-1μm and arranged closely and orderly.The adhesion amount of S.mutans of FACF was significantly less than that of dentin(P<0.05),and the amount of biofilm per unit area on FACF surfaces was significantly lower than that of HA,FA,and dentin surfaces(P<0.05).FACF could prevent S.mutans from growing into dentin tubules.Conclusion:Under near physiological conditions,a layer of dense and orderly FA crystal film can be regenerated on the dentin surface.The crystal structure of this layer can reduce the adhesion of S.mutans and formation of biofilm,and act as a physical barrier to the growth of S.mutans into dentin tubules.