|
|
| |
|
|
|
Researchers at the Forsyth Institute and Massachusetts General Hospital in Boston and Universidade Federal de Sao Paulo (UNIFESP) in Brazil have successfully used tissue-engineering techniques to regenerate rat tooth crowns.
The advance follows Forsyth's widely-publicized regeneration of pig tooth crowns in 2002 and adds evidence that it may, one day, be possible to grow new human teeth from an individual's own cells.
"We are very excited because mammalian systems tend to operate in similar ways," said Pamela Yelick, Ph.D., assistant member of the Forsyth staff and the principal investigator. "Having regenerated teeth of a second mammalian species allows us to hope for similar success with human teeth."
The Forsyth team found that it was possible to maintain individual tooth-forming cells in culture for six days before implanting
them - thus demonstrating that adult dental stem cells can give rise to tooth crowns containing dentin and enamel and indicating that it might be possible to expand enough such cells in culture to grow full-sized teeth.
The advances were reported in the July 2004 Journal of Dental
Research.
In bioengineering rat teeth, the scientists used techniques similar to those previously used at Forsyth to form pig teeth. In both sets of experiments, researchers "seeded" cells obtained from immature teeth of animals onto biodegradable polymer scaffolds. The scaffolds were then implanted in the abdomen of rat hosts. Within three to six months, depending on the particulars of the experiment, small, recognizable tooth crowns formed.
Previously, Forsyth researchers had grown small teeth from dissociated pig molar buds, but were uncertain whether the new teeth emerged from "clumps" of incompletely dissociated tooth tissue. In the newly reported work, the scientists grew individual, dissociated tooth bud cells in culture before implanting them.
In both sets of experiments, the Forsyth scientists used "adult" dental stem cells, which give rise only to dental tissue. They did not use "embryonic" stem cells, which can be induced to form a variety of different tissue types.
The scientists' goal is to develop methods for replacing lost or missing human teeth by growing new teeth, in an individual's jaw, from an individual's own cells.
They are currently working on the possibility of growing new teeth in a mammalian jaw, and are beginning to work with human tooth tissues. "Within a year, we expect to determine whether the methods we use to regrow animals' teeth will be useful in regenerating human teeth," Yelick said. "If the methods prove effective, it will be at least seven years before they can be tested clinically in humans."
The research was funded by the Harvard School of Dental Medicine and the Center for Integration of Medicine and Innovative Technology, with additional support from CAPES
(Coordenacao de Aperfeicoamento de Pessoal de n¡vel Superior); UNIFESP; and the Forsyth Institute.
|
|
| |
|
|
