The situation in China is improving, he added, especially in big cities such as Shanghai and Beijing, with more people visiting dentists regularly. But it's going to take a long time before the situation in China is comparable with that in the US.

Fear is a key reason why Chinese people are reluctant to see dentists. Others are awareness and healthcare coverage, he said.

Chang Yunping, an orthodontist with the Shanghai Stomatological Disease Center, said that unpleasant childhood experiences with dental treatment can evolve into a fear of seeking treatment as an adult.

"That's especially true in China, where dental services were extremely primitive and painful 20 years ago," said Chang.

A 2006 study in Australia by the University of Adelaide found that 16.4 per cent of adults and 10.3 per cent of children feared dental treatment, with females more likely to be scared.

"It was indeed a horrible experience pulling out teeth at the hospital when I was a kid. It hurt so bad that my whole face was swollen," said 27-year-old Li Jie, an office clerk in Shanghai.

"I wouldn't say that will stop me from going to dentists. I still go if my gums are bleeding. But if I feel fine, I probably wouldn't want to go."

Part of the reason why an increasing number of adults in China are deciding to get braces is that advances in orthodontic technology have made the treatment less painful and noticeable.

One of the top reasons why many adults have avoided braces is because the traditional "train tracks" are bulky and uncomfortable. Ceramic braces today are of a similar color to teeth and so less noticeable. They're also much smaller, which increases the level of comfort.

The latest type of orthodontic brace is called Invisalign, a treatment that relies on sets of clear, removable teeth aligners used as an alternative to traditional metal dental braces.

The aligners are completely transparent and far less detectable than traditional wire and bracket braces. That's helped them gain popularity among adults who want to straighten their teeth without the look of traditional metal braces.

The aligners are also more comfortable than braces because the device's removable nature means that food can be consumed without the encumbrance of metallic braces.

Jsmile's Ma said that Invisalign, which costs about 60,000 yuan, is the top choice for adults at his clinic wanting to have their teeth straightened.