What works for one person, may not work for another when combating oral disease, according to dental researcher Dr Sara Filoche (University of Otago, Wellington).

Filoche is investigating bacterial management regimes to combat oral disease, a health issue most people will have to deal with at some time.

"Oral disease includes tooth decay or gum disease or both, and it's a serious and growing problem in New Zealand. It's often associated with other health issues, as well as low socio-economic status."

Researchers are testing different washes with a unique artificial mouth - developed by the Dental Research Group - which grows plaque and simulates growth conditions akin to oral disease. Washes are seen as an important additional treatment to normal dental care because they can reach inaccessible areas of the mouth.

"The results so far have been rather a surprise," she says. "Most interestingly, we've found that plaque bacteria from different people react differently to the same mouthwashes - there's not a consistent result with one type of wash.

"It's not a simple equation either of one type of mouthwash zapping all bacteria. Some washes, like manuka honey, will work on one type of bacteria, while Listerine will affect another."

However, with 50 per cent of New Zealand five year olds now having some kind of tooth decay and, in some areas, 70 per cent, the need for determining the best additional treatment for oral disease is taking on new urgency. Filoche hopes her research will provide some answers.