By gum, that's glum! Losing your teeth is no laughing matter as research shows victims are up to a third more likely never to have a good chortle

Losing your teeth really is no laughing matter, a study suggests.

Researchers have found that people who are missing some of their pearly whites are up to a third more likely never to have a good old-fashioned chortle.

Perhaps surprisingly, however, the lack of laughter is unrelated to any reluctance to show off a less-than-perfect dental alignment.

According to experts writing in the Journal of Prosthodontic Research, the real reason is that difficulty in eating hard foods may weaken the muscles used in laughing and make them less effective.

Previous research has found that older people laugh less and the researchers looked at whether loss of teeth was a factor.

Researchers have found that people who are missing some of their pearly whites are up to a third more likely never to have a good old-fashioned chortle (Stock image)

They analysed dental data on nearly 160,000 men and women aged 65 and over. More than 9,000, or around six per cent, had a low level of laughter - defined as laughing never or almost never.

When the researchers matched that with tooth loss, they found that compared with people who had 20 to 32 teeth, those who had nine or fewer - and did not wear dentures - were 30 per cent more likely not to laugh. Among those with 10 to 20 teeth and no dentures, the risk was 14 per cent higher.

According to the research team, difficulty in eating hard foods in a likely cause.

It leads to less exercising of the chewing - or masticatory - muscles, ultimately making them weaker. These muscles also have key roles in facial expressions, so a decline in their strength would make laughing difficult.

According to experts writing in the Journal of Prosthodontic Research, the real reason is that difficulty in eating hard foods may weaken the muscles used in laughing and make them less effective (Stock image)

Meanwhile, there was no difference in laughter frequency between those wearing dentures and those with 20 or more teeth.

'The use of dentures prevented the decline in masticatory functioning after tooth loss, and consequently, the frequency of laughter was maintained,' said the researchers Tohoku University Graduate School of Dentistry, Japan.

'Our results suggest the possibility that dental treatments can prevent a decrease in laughing frequency after tooth loss.'

Laughter has been linked to a number of health benefits - including boosting the immune system, increasing pain tolerance and improving heart functioning.