The Mini Marbles

牙膏問世前，人們用牙粉刷牙。牙粉是碳酸鈣和肥皂粉的混合物，pH值高，會引起口腔組織發炎。隨著科學技術的不斷發展，各種類型的牙膏相繼問世，牙膏成了我們日常生活中常用的口腔清潔用品。那牙膏中的“小玻璃球”是什么呢？又是如何修復我們腐蝕受損的牙齒的呢？

Tiny glass balls in toothpaste may halt decay and also help with sensitive teeth. The balls， which are no wider than a human hair， contain calcium and phosphate， crucial components of tooth enamel. The balls then start to dissolve in the moisture in the mouth， leaching out calcium and phosphate.

They have been developed to help repair teeth damaged by decay， but where the damage is not severe enough to warrant a filling. The balls， which have been created by a team of dentists and scientists from Queen Mary， University of London， are made from calcium phosphate glass.

Early trials suggest that this forms a new surface on the teeth in less than three hours， with the balls dissolving completely in under eight hours. There are already several toothpastes made with glass particles on the market. They also say that the higher phosphate content means their glass balls repair teeth more effectively.