A mother-of-four who chewed sugar-free gum for up to seven hours a day is now facing a major operation to fix her worn-out jaw.
Claire Embleton's chewing gum habit wrecked the joints at the side of her mouth leaving her unable to open her mouth more than 1cm.
The 38-year-old could now be left with scars after the operation which will see a surgeon cut into the side of her face to replace the joints for metal plates.
"When doctors told me chewing gum had overworked my jaw and worn out the joints, I was shocked," the IT manager said.
"I had always believed chewing gum was healthy. I chewed it after eating and drinking and ensured I only ever had sugar-free brands.
"I never imagined what I thought was a harmless and healthy habit could be so damaging."
Mrs Embleton, who is married to Daniel, 40, had chewed gum for around five years before two years ago she occasionally experienced a clicking feeling in her jaw joints when she ate two years ago.
"I always chewed sugar-free gum after meals and drinks. Looking back it wasn't an addiction but I suppose it had become a habit because when I add up time, I was chewing for five hours a day in the week and at weekends it could be as much as seven hours.
"But there was no warning on the packets that gum should only be used for a certain amount of time.
"And I while sometimes I got a clicky sensation in my jaw when I chewed I didn't worry as it wasn't painful."
But a year ago when, as she chewed her favourite brand of gum, her mouth suddenly locked shut.
"The day my jaw froze was a frightening experience. One minute I was laughing and chatting normally - the next, without any warning, my jaw was suddenly locked in an almost shut position.
"It was incredibly painful and meant I couldn't eat or talk properly."
Since then she has been unable to open her mouth fully.
Mrs Embleton, from Liverpool, was diagnosed with a condition known as Temporomandibular Joint Disorder (TMJD).
"Far from being a healthy habit, my constant chewing had overused the jaw muscles ... the jaw was not meant to be constantly chewing and should be rested between eating."
Mrs Embleton stopped chewing gum, hoping with rest and painkillers her jaw would improve.
Over the next six months she underwent physiotherapy and an operation known as an arthroscopy to flush the bones of any debris and remove thickened cartilage and scarring.
But the treatment didn't work and she is now about to undergo the jaw replacement surgery.
"The consultant has explained the surgery will take a whole morning and involve cutting into the sides of my face above my ears and into my neck. I will be in hospital for around five days and unfortunately there is a risk of scarring.
"It is major surgery and it terrifies me. But I don't feel I have any choice.
"Right now I have difficulty talking and can hardly eat. I just want to get back to normal."
Mrs Embleton, whose four children are aged from two to 16, said: "Sugar-free gum might be healthy for teeth but I don't let my children chew any gum now."
She believes warnings should be put on gum packets and is telling her story to highlight the dangers.
"I always thought sugar-free gum was healthy but this has been a nightmare and I don't want anyone else to suffer as I've done."
British Dental Association scientific adviser Professor Damien Walmsley said: "In moderation chewing sugar-free gum, especially after a meal, can benefit your oral health by stimulating saliva production. This will help neutralise acid from the bacteria which cause tooth decay.
"However excessive strain on the jaw, whether through excess chewing or tooth grinding, can lead to a number of problems ranging from jaw pain and stiffness, to headaches and difficulty in jaw movement. "