Wales' top doctor has said more needs to be done to improve the state of children's teeth.
The Welsh government currently provides some nursery children with tooth brushes and fluoride varnishes.
But in his annual report, Dr Tony Jewell said "alternative methods" were needed so teeth could benefit from fluoride.
On average, four children in a class of 30 five-year-olds will have experienced dental pain in the last 12 months.
The chief medical officer Dr Jewell said it was a sign of deprivation and a measure of inequality.
He added that the figure rose to six children in a class of 30 in Blaenau Gwent
The Welsh government's "Designed to Smile Programme" provides more than 60,000 children with a toothbrush in school as well as fluoride varnish to three to five-year-old children.
Dr Jewell said: "In Wales we need to get more teeth in contact with fluoride via alternative methods.
"More than 5,130 general anaesthetics were given to children to remove teeth last year in unfluoridated south east Wales.
"This should be compared to fluoridated Birmingham (a similar size population) where just over 2,700 children received the same treatment."
Some areas of England already use fluoride in the water system.
But critics argue the long-term health risks of fluoridation are unknown. However, advocates, including much of the medical profession, say it is a safe, proven way of improving dental health.
The Designed to Smile scheme helps disadvantaged communities.
It sees dental health support workers deliver supervised tooth-brushing programmes in schools, along with oral health advice.
Dr Jewell's report said children living in less affluent areas were more likely to experience decay and were likely to have more tooth decay.
Half of the five-year-old children across Wales have no decayed teeth, the other half have on average four teeth decayed, filled or extracted, the report explained.
Dr Jewell said: "However, it is more than simply teaching children how to brush their teeth.
"The scheme also delivers direct clinical interventions that have been shown to prevent decay. Wales lags behind the rest of the UK in terms of tooth decay in children and we will do all we can to improve the situation."
In his report, Dr Jewell also warned that increasingly unhealthy lifestyles might lead to a fall in life expectancy.
The problem was diseases caused by obesity, smoking, alcohol and fitness, with under one in three taking enough daily exercise.