The researchers demineralized the 180-million-year-old fossil of an ichthyosaur...and left behind soft, flexible tissues.

研究人员对1.8亿年前的鱼龙化石进行物质处理，留下柔软且有韧性的组织。

That environment favors bacteria like mutans streptococci and Lactobacillus, which demineralize enamel and the dentin beneath it, and if untreated, it can eventually result in a cavitated caries lesion.

酸性境下的优势菌例如变形链球菌和乳酸杆菌，可釉质及其下层的本质脱，如果不加治疗，最终会形成空洞型龋齿。

So typically, dental plaque can form on the surface of teeth, b ut if the pH of the local environment around the tooth surface remains above about 5.5, enamel will not demineralize.

一般情况下，菌斑形成于齿表面，但当表面局部境的pH值持续高于5.5时，釉质将不能脱化。