Scientists have found a new technique to re-grow dental enamel from cultured cells.

A team of researchers from the Institute of Medical Science, the University of Tokyo, Japan, reports that epithelial cells extracted from the developing teeth of six-month-old pigs continue to proliferate when they are cultured on top of a special feeder layer of cells (the feeder-layer cells are known as the 3T3-J2 cell line).

This crucial step boosts the number of dental epithelial cells available for enamel production.

In the study the researchers seeded the cultured dental epithelial cells onto collagen sponge scaffolds, along with cells from the middle of the tooth (dental mesenchymal cells).

The scaffolds were then transferred into the abdominal cavities of rats, where conditions were favourable for the cells in the scaffolds to interact and develop. When removed after four weeks, the remnants of the scaffolds were found to contain enamel-like tissue.

The key finding of this study was that even after the multiple divisions that occurred during propagation of the cells in culture, the dental epithelial cells retained the ability to produce enamel, as long as they were later provided with an appropriate environment.

The idea for the culturing technique originates from 1975, when Dr J G Rheinwald and Dr H Green of Harvard Medical School, USA, reported the use of feeder layers for culturing epithelial cells from the skin. The 3T3-J2 cells used in the current study were gifted by Dr Green.

The cell-scaffold approach is based on tissue-engineering technology developed at the Forsyth Institute, USA and was applied by one of the Tokyo researchers to produce enamel-like tissues in 2002.

Now that dental epithelial cells can be propagated in culture, the next step will be to achieve the same success with their partners in tooth formation, the dental mesenchymal cells.

Further development of this technique will be aimed toward production of tissue to replace damaged or missing enamel, and ultimately, regeneration of whole teeth.

The findings were reported during the 85th General Session of the International Association for Dental Research, in New Orleans, USA.