Metal mouth. Jaws. Ugly Betty. It's no fun having braces as a teenager, but what about when you are an adult? In the US, the number of adults seeking braces increased by 37% between 1994 and 2004, according to the American Association of Orthodontists. In the UK,

Les Joffe, secretary of the British Society of Orthodontists, has seen the number of adults seeking orthodontic treatment at his private practice increase from 25% to 70% in less than 10 years. "The stigma of wearing braces is certainly less than it was," he says. And the stigma of having bad teeth is worse than ever.

The British are supposedly famous for having ugly, snaggled teeth, which perhaps explains why people are seeking aesthetic improvements in greater numbers - we now spend £360m a year on cosmetic dentistry. But it can be a costly and slow process.

In the US, braces have become almost a status symbol, because the cost of them can run to several thousand dollars. Here, they can cost from £2,000 to £8,000 or more, although if a patient's problem is severe enough - for instance, if the bite is affected, which might involve jaw surgery, and it is not just an aesthetic issue - it can be done on the NHS.

While orthodontics can make a real difference to a person's health - an incorrect bite can cause jaw and muscle strain and headaches, and it can be harder to clean crooked teeth - many are motivated by the search for a perfectly straight smile, and it seems that more and more of us are prepared to spend time and money on achieving that.

For a relatively simple case, says Joffe, treatment can take around nine months, but people can be in braces for two years or more.

Tessa Evelagh, 52, got braces when she was 49. "It was the best thing I ever did," she says. "After 25 years of thinking about it, I finally took the plunge, and now they've come off, I can't stop smiling. They have sorted out an overjet [where the upper teeth stick out horizontally] - my bottom teeth were biting into my palate - and I feel more confident. I hadn't realised quite how self-conscious I was about my teeth, and I think I generally look better, with a better jawline and even less pronounced nose-to-mouth lines."

For those who are horrified by the idea of metal "train track" braces, there are less noticeable options. Ceramic braces have white ceramic brackets that are glued to the front of the teeth, making them less obvious than metal brackets. The Invisalign system is especially popular with adults as it uses a series of clear plastic mouthguards to move teeth into place.

Dr Asif Chatoo runs the London Lingual Orthodontic Clinic and specialises in lingual braces - fixed braces that are placed behind the teeth - which are also popular with adults because they cannot be seen. The average cost for an upper and lower set is around £6,500. "My practice is predominantly adult-based," says Chatoo, "and we have more and more adults becoming interested. I mainly used to see younger adults, from 20 to 35; now the patients I see can be over 50."

Grace Whitty, 26, Registrar at a prep school, lives in Staines

"I had always thought that my teeth needed straightening out, but when I was a teenager, nobody thought it was necessary. It was something that always bothered me - my teeth stuck out at the top and my bottom teeth were wonky.

I decided to do something about it last year. My wisdom teeth were coming through and it felt as though my top teeth were moving. My bite wasn't right and my dentist said that the only way to correct it was to have a brace.

My fiance wasn't keen. He said my teeth were fine and he was worried about the cost - £3,000 - when we were supposed to be saving for our wedding and a deposit on a house, but he knew it was important to me. When he first saw them he laughed, but now he is used to it.

I was self-conscious at first but I haven't had any bad reactions from people. My friends call me Ugly Betty or Bracey Gracey but it's only a joke. It doesn't bother me.

I've probably got a year and a half to go, then I'll have to wear a retainer every night for a year, then after that I'll have to wear a retainer probably every other night for ever. It's quite a commitment but it's worth it.

I can already see a change in my teeth. I'll get married when the braces come off and I'll have been really glad I've done it."

Jane Jacob, 29, Buyer for an electronics company, lives in Bedford

"I got married last year and my braces came off for the wedding and honeymoon. That will slow the treatment time up, but not by much - I've had them on for about 11 months and I've got about six months to go.

I had braces when I was a teenager because I had a lot of overcrowding. As I got older, my teeth started to move back. I thought I was too old to have braces, but when I went to a new dentist, he said I could do it. My husband didn't think I should have it done - he said he thought I was fine as I was - but once he saw I had made my mind up, he was really supportive.

I was worried about what people would think and for the first few weeks I was self-conscious, but then I got used to it. I'm aware that people stare at the braces sometimes, but I've never had anyone make any mean comments."

Mike Clough, 35, Bank worker, lives in Douglas, Isle of Man

"I had been thinking about getting braces for a while and I thought that if I don't do it now, I never will. I had crooked teeth, I wasn't happy with my smile and it was sapping my self-confidence. I researched it on the internet and I came across lots of adults who were having it done. I thought that if they could do it then so could I. My wife was really supportive, which gave me the confidence to go ahead.

I have had my upper brace on since May last year, and the lower one since July. I decided to go for the ceramic brace - tooth-coloured fittings - with the metal wire, which isn't as noticeable as the full-metal brace. It costs about £2,500 and will take eight months to a year, depending on how quickly the teeth move. I can already see a great improvement.

At the start, I was really self-conscious, but now I'm relaxed about it. I'm actually happier smiling in braces than I was without them, because at least I'm doing something about my teeth. I've only ever had four people mention them - three at work, and one man when I was out one night, and he only asked about them because his wife had braces. My boss pointed out that the braces have given me a bit of a lisp, but it was just gentle ribbing.

I think it is probably a bit harder for men to get braces because they are not supposed to care about their appearance, but I'm really glad I'm doing it. I was really worried about doing it before, but I've been amazed at the lack of reaction from other people."

Lee Dinsdale, 31, Stockbroker, lives in Manchester

"I've met a lot of men my age who have said to me, 'I'd love to get my teeth done but I couldn't face having braces.' They seem to think I'm really brave or stupid.

I never had braces when I was younger and I always regretted it. My teeth were really crooked and it was affecting my confidence so I decided I wanted to get them done before I was 30. At the time, celebrities such as Tom Cruise had braces, which suddenly made them seem acceptable for adults. The whole process has taken longer than I originally thought. The braces would move my teeth in such a way that I would have an overbite and would need jaw surgery to correct it. This meant I could not go private and the NHS only provide the metal braces, not more subtle types. I was anxious to begin with, as I know that when I see someone in braces, even now, I think 'That isn't a good look', so other people probably think the same about me.

However, I had convinced myself it would be worth it. You never know what people's first impressions of you are so I don't know what people really think when they meet me. I've not seen any other guys in Manchester with braces so I do get a few funny looks. I've not really encountered much "bracism". I've had the odd idiot say something, but my view is that braces are such an easy target to take the mickey out of, it doesn't exactly show a high level of intelligence, does it?

I don't really know how girls react, but it's certainly not an advantage. A few have said I will look a lot better when they're off. With clients, nobody has said anything, but I am aware braces make me look younger, which could affect their perception of me. The only thing they have really affected is sport. I started playing football but was apprehensive about tackling and getting an elbow in the mouth so I stopped.

I go through phases of not being bothered by the braces, to being really self-conscious. At the moment, I'm just a bit worn down from having them because they've been on for so long. I'm trying to remember what life was like without them. I moved to Manchester three years ago so all the friends I have here have only known me with braces on. It will be interesting to see if people's reactions to me change once they come off, hopefully in about six months' time."

Kathryn Ord, 34, Civil servant, lives in north London

"My teeth were very crooked and I had a deep overbite. I was self-conscious about my teeth - I tended to cover my mouth when I smiled - but not bothered enough to do anything about them. Then a colleague got braces and I decided to look into it. My dentist referred me to the Eastman Dental Institute - if you are a bad enough case, you can get treated on the NHS - and I was put on a waiting list. Two years later, braces were put on my top and lower teeth. I exchanged being self-conscious about my teeth to being self-conscious about my braces, and then stopped caring altogether. People did look, but I think they were more interested than horrified.

After a year, I had my jaw broken and reset to correct the bite. I couldn't talk properly for a couple of months, or chew, but you can survive on soup. My chin and lower lip were numb for three months. It wasn't pleasant, but I had been warned, so it wasn't a surprise.

People would say, 'Why are you going through all this?' I'm really looking forward to getting them off in a couple of months. My teeth are straight and my bite is much better - before, my top teeth would completely cover my bottom teeth when they were closed. I'm really pleased with the result."

Rebecca Smith, 29, Pharmaceutical company worker, lives in Bathgate, West Lothian

"I've had my braces on for six months and I've been told that I'll probably have them for two years, but I'm hoping it won't be that long. I thought about having it done for a long time. I had a tooth that stuck out and I noticed it in every photograph: I could change my hair or my clothes, but there was always this one thing. I just thought, If I don't do something about it now, it will always be that way.

When I was a teenager, we moved house too often to stay with one dentist and so I never had braces. And the idea of them put me off - I thought I would get bullied, and I was at that age when I was starting to get interested in boys. Now I wish I'd had braces, but you always wish you had done things when you're younger.

I talked to my husband about it, only to find out that he thinks braces are quite sexy. We did have to think about the cost - £2,600 - but my teeth are, hopefully, going to last me the rest of my life.

The only problems I had were in the first few weeks. I found it hard to talk and I was lisping a lot. I still find it difficult to bite into things, so I always have to use a knife and fork and cut my food into little bits -no burgers or popcorn at the cinema for me. It was really embarrassing at the beginning; I'd be eating lunch at my desk and I'd accidentally spit food across the table. Thankfully, I have very understanding colleagues.

It has been a new experience, but I can't wait for them to come off."