More than half of all children in Singapore have one or more rotten teeth by the time they start primary school.

This is a worrying trend because bacteria from their milk teeth can affect the development of their permanent teeth.

That is why the Health Promotion Board (HPB) is introducing oral care programmes to pre-primary children, starting in August. HPB said it plans to reach out to children in all childcare centres within five years.

A report on the oral health of schoolchildren found that the proportion of children with dental caries at the age of seven had gone up from 47.6 per cent in 2003, to 50.6 per cent last year.

“If left untreated, decay on the primary (milk) tooth can affect the developing permanent tooth,” said School Dental Service senior deputy director Eu Oy Chu. This is because bacteria from the milk tooth can result in an abscess that will spread to the tooth growing under it, she said.

Among seven-year-olds, more foreign children (56 per cent) had caries than local children (51 per cent). Generally, more boys than girls had bad teeth.

One in four Primary 6 pupils last year had caries on the permanent teeth. This is a significant improvement from 2007 when slightly more than one in three had caries. And among 15-year-olds, 41 per cent had caries last year, slightly lower than the 42 per cent in 2007.

Local children continued to have better teeth as they aged than foreigners. By the time they were 15 years old, 59 per cent of local children had no decayed, missing or filled teeth, compared with 57 per cent of foreigners that age.

Eurasians have the most problem-free teeth (71 per cent), followed by Indians (64 per cent), Malays (60 per cent), and Chinese (58 per cent) coming in last.

Dr Matthew Lau, a dental officer with the School Dental Service, told The Straits Times: “We are seeing more children with decayed and filled teeth.”

He asks parents if the child takes lots of sweet foods and beverages, if he still falls asleep with a milk bottle, or holds food in his mouth for long periods – all bad habits that lead to tooth decay.

Dr Lau urges parents who give their children sweet treats to do so immediately after a meal rather than any time the child wants. This limits the amount the child takes. He also tells parents they need to brush their child’s teeth “until a child develops the dexterity to do a good job on his own”.

Usually, a child who can tie his shoelaces should be able to brush his own teeth. But Dr Lau added that parental supervision is still necessary to ensure that the child is doing a good job.

Parents should start taking their children to the dentist when they turn one, or when they get their first tooth, he said.

Ganesh Mohandas, who turns five this month, started brushing his own teeth this year, but his parents would follow up with a second round of brushing to make sure that nothing is missed.

His mother, Mrs R. Mohandas, said they started brushing his teeth from the time he was just six months old.