A common type of bacteria that leads to dental plaque can make certain cancers "melt” and disappear, a new study has claimed. According to experts at Guy's St. Thomas’ and King's College, London, those suffering especially from head and neck cancers, the bacteria led to much better outcomes. Doctors say in your mouth, one of the most common types of disease-causing bacteria is linked to plaque and gum disease - Fusobacterium which appears to have the ability to kill up to 99 per cent of some cancers.

For the study, initially, scientists used modeling to help identify which bacteria may be of interest to further investigate. Then they studied the effect of the bacteria on cancerous cells in a laboratory. An analysis of the tumour data of 155 patients with head and neck cancer was also performed.

In the laboratory studies, researchers put quantities of the bacteria in Petri dishes and left them for a couple of days. Later, it was found that the cancer had almost disappeared. There was a 70-99 per cent reduction in the number of viable cancer cells in head and neck cancer cells after being infected with Fusobacterium.

And so, the scientists say that those with Fusobacterium bacteria within their cancer had better survival odds compared with those who did not. According to the study, the bacteria – especially in the head and neck cancers is associated with at least a 65 per cent cutback in risk of death.

Scientists say the findings, published in the journal Cancer Communications, could help guide treatment for patients with head and neck cancer - which include cancers of the mouth, throat, voice box, sinuses, and the nose.

"In essence, we found that when you find these bacteria within head and neck cancers, they have much better outcomes. The other thing that we found is that, in cell cultures, this bacterium is capable of killing cancer,” Dr. Miguel Reis Ferreira, senior study author told The Sun. "What we are finding is that this little bug is causing a better outcome based on something that it's doing inside the cancer. So, we are looking for that mechanism at present, and it should be the theme for a new paper in the very short-term future," he added.

Dr. Ferreira said the bacteria can also help in changing to course of cancer treatment. "What it could mean is that we can use these bacteria to better predict which patients are more likely to have good or worse outcomes. And based on that, we could change their treatment so make it kinder in the patients that have better outcomes or make it more intense in patients that are more likely to have their cancers come back," he added.

According to scientists, fusobacterium is a type of bacteria commonly found in the human mouth and gut. It is usually harmless and helps with normal processes, but sometimes it leads to serious infections, especially when you have a weak immune system. It can contribute to gum disease or, in rare cases, more serious infections like abscesses.

A few recent studies have said fusobacterium has been linked to bowel cancer, as the high levels of this bacteria in the gut might be associated with an increased risk of developing colorectal cancer.