Six-year-old Ryan Coutinho wasn't used to smiling. He felt embarrassed after losing almost all his teeth at the age of three.
Now he does. And can't stop showing it.
But getting here wasn't easy, says dentist Amanda Mattos.
The boy lives in a rural area near Guajeru, a poor town in north-eastern Brazil. He had his teeth
pulled out as a result of early cavities. Only a few on his lower arch remained.
Ms Mattos, 25, met Ryan for the first time two years ago, during a social project at the boy's school.
"I had never seen something like this," she told the BBC. Ryan's teacher told her that he avoided smiling and did not engage much with other students.
Ms Mattos offered to treat the boy after contacting the boy's mother through the teacher. But the mother refused, believing that her son would be reliving the drama of his operation.
"They are all very modest, live outside the town and didn't understand the procedures," the dentist said. "They were still shaken by the process that removed all his teeth."
Ryan's story could have ended here. But two years later, by coincidence, his mother got a job as a cleaner at the public clinic where Ms Mattos works.
Soon afterwards, the boy had a pain in one of his remaining teeth. He went to the clinic for treatment and met Ms Mattos again.
"I asked him what he wanted. He smiled and said: 'a smile like my friends'," the dentist said.
The mother was still reluctant to accept the treatment. But she later talked to the father and they finally agreed to take up the offer.
The town's public health service did not pay for the procedure, so Ms Mattos, who owns a private
clinic in a nearby town, brought equipment and offered to do it for free.
For several weeks, Ryan visited her after school to take X-rays and impressions. He was disappointed every time he returned home without his new teeth, Ms Mattos said.
Then, on 14 October, two days after Brazil's Children's Day, he finally got a new smile - a denture for his upper arch.
"We all cried. It was very moving," the dentist said.