For thousands of years, losing teeth has been a routine part of human aging.

Researchers are close to growing important parts of teeth from stem cells, including creating a living root from scratch, perhaps within one year.

According to Pamela Robey of the NIH. ‘Dentists say, “Give me a root and I can put a crown on it.”‘ In a few years dentists will treat periodontal disease with regeneration by using stem cells to create hard and soft tissue; they will take out a tooth that is about to fall, and reconnect it firmly to the regenerated tissue.

Although nobody is predicting when it will be possible to grow teeth on demand, in adults, to replace missing ones, a common guess is five to ten years. Baby and wisdom teeth are sources of stem cells that could be ‘banked’ for future health needs, says Robey.

China warned Google and other popular Web portals Monday that they must do more to block pornographic material from reaching Chinese users, the latest in a series of government crackdowns targeting Internet content.

The crackdown focused on pornography but is part of a larger Chinese effort to control freedom of expression and root out material it considers destabilizing, such as sites that criticize the Communist Party, promote democratic reform or advocate Taiwan independence.

Pornography is banned in China but remains widely available on and off the Internet. Popular Chinese Web portals frequently show sexually explicit pictures and provide links to pornographic Web sites.

The announcement said Google and Baidu, China’s two most heavily used search engines, had failed to take “efficient” measures after receiving notices from the country’s Internet watchdog that they were providing links to pornographic material.

Google asserted that it abides by Chinese law and does not generate pornographic content.

The statement also criticized popular Web portals Sina and Sohu, as well as a number of video sharing sites and popular online bulletin boards such as Tianya, that it said contain problematic photos, blogs and postings.