More than 10,000 children in St Helens have not seen an NHS dentist in the last year, according to newly released figures.
The British Dental Association said the rate of check ups for children is "national disgrace" and put it down to a lack of information to engage hard-to-reach families.
NHS data shows that 33 per cent of children in St Helens have not had a dental check-up in the 12 months to September 2018, compared with the 41 per cent average across England.
It means 11,918 children in the area have not been for their check-up over the period, despite NHS guidelines saying they should be seen at least once a year.
The remaining 67 per cent did see a dentist during the period.
NHS dental care for children is free, but a poll conducted by the BDA last year revealed that one in four parents are unaware that there is no charge for routine check-ups for children.
The BDA’s chair of general dental practice, Henrik Overgaard-Nielsen, said that current outreach programmes were more likely to target people who already visit their dentist.
He said: "The fact nearly five million children are missing out on free dental care is nothing short of a national disgrace, but is the logical result of policies from successive governments.
"In Scotland and Wales dedicated national programmes are reaching out in nurseries and primary schools, yet in England the authorities have offered a few posters to pop up in dental practices.
"Tooth decay is a preventable disease and remains the leading cause of hospital admissions for children, but instead of public information campaigns Westminster has offered radio silence."
Over the 12 months to June, 2,220 children received some kind of urgent dental treatment in St Helens.
According to dentists, these are mainly tooth extractions or fillings.
Among adults, 91,200 people in St Helens saw an NHS dentist in the 24 months prior to October 2018.
That is 64 per cent of the population, compared with 51 per cent across England.
A Department of Health and Social Care spokesman said: “We want every single child and adult to have access to NHS care, whatever their background or location – and last year a record 6.9 million children were seen by a dentist with numbers rising every year.”