Division of Advanced Prosthetic Dentistry.
J Dent Res. 2014 May;93(5):525-9. doi: 10.1177/0022034514524782. Epub 2014 Feb 19.
Corrosion of titanium is the major concern when it is used for dental treatment. This study aimed to investigate the mechanism of the microbiologically induced corrosive properties of titanium. An experimental well was made of polymethyl methacrylate with pure titanium at the bottom. Viable or killed cells of Streptococcus mutans were packed into the well, and pH at the bacteria-titanium interface was monitored with and without glucose. Before and after 90-minute incubation, the electrochemical behavior on the titanium surface was measured by means of a potentiostat. The oxygen concentration under bacterial cells was monitored with oxygen-sensitive fluorescent film. The amount of titanium eluted was measured by inductively coupled plasma-mass spectrometry. The corrosion current and passive current under killed cells were low and stable during 90 min, while those under viable cells increased, regardless of the glucose-induced pH fall. The polarization resistance and oxygen concentration under killed cells were high and stable, while those under viable cells decreased. No elution of titanium was detected. Viable bacterial cells may form 'oxygen concentration cells' through metabolism-coupled oxygen consumption and subsequently induce corrosive properties of the titanium surface.
钛的腐蚀是其在牙科治疗中应用时主要关注的问题。本研究旨在探讨微生物诱导的钛腐蚀性的机制。用聚甲基丙烯酸甲酯制成一个实验井，底部为纯钛。将变异链球菌的活菌或死菌装入井中，监测有无葡萄糖存在时细菌-钛界面的 pH 值。在 90 分钟孵育前后，通过电位计测量钛表面的电化学行为。用氧敏荧光膜监测细菌细胞下的氧浓度。通过电感耦合等离子体质谱法测量溶出的钛量。在 90 分钟内，死细胞下的腐蚀电流和钝化电流较低且稳定，而活细胞下的电流增加，而不管葡萄糖诱导的 pH 值下降。死细胞下的极化电阻和氧浓度较高且稳定，而活细胞下的则降低。未检测到钛的溶出。活细菌细胞可能通过代谢偶联的氧消耗形成“氧浓度细胞”，从而诱导钛表面的腐蚀性。
