Happy smiles are back on the faces of these children who are beneficiaries of Smile Train, a charity pledging to repair cleft lip and palate for poor children in developing countries.

In the end, they gathered 17 children with cleft lips and palates, including Dorje's son, and all of them had successful surgeries at the West China Hospital of Stomatology.

"Smile Train changed those kids' life," says Traga Lhamo, the older sister. "The doctors and nurses in the hospital were very nice and supportive."

Now, Dorje can't help smiling when his son smiles.

Wang Li, 25, from Suqian, Jiangsu province, was one of the first children who benefited from the Smile Train program.

She had free surgery 14 years ago, and lives a normal life today. She got married in 2012, and has given birth to a healthy son.

But as a little girl, she used to avoid crowds because of her cleft lip, and always wrapped her face with a scarf when she went out.

Wang once told the media she couldn't imagine how her life would be without help from Smile Train.

With established programs in 87 countries, the charity not only provides free surgeries to children, but also trains local doctors and provides equipment to hospitals to perform cleft operations.

So far, Smile Train has trained more than 20,000 medical staff members across the world, including 12,000 in China.

"Many people asked me ‘Why cleft?'," says Wang, the chairman of the charity, who was born in Shanghai and emigrated to the US with his parents when he was 8. "The thing is, when the kids make fun of a kid with cleft, the psychological damage is unbelievable.

"We do one thing and we focus. We put a smile back on a child's face."