A 'scandalous' delay means some children are facing backlogs of almost 10 years for access to the HSE School Dental Screening Service.
That is according to the Irish Dental Association (IDA), which has said children who should be receiving three check-ups in primary school are not being seen until fourth year of secondary school.
Children are meant to have check-ups in second, fourth and sixth class.
Chief Executive of the IDA, Fintan Hourihan, told Newstalk Breakfast this is not happening.
"It has gotten this bad, and is quite scandalous, because of years of neglect by running down a service, by the collapse in the scheme for adults, which is bringing adults in for care into clinics which are struggling to cope with looking after children and vulnerable patients," he said.
"It really is quite unbelievable."
'The most vulnerable'
He said some parents can afford to go private, but this service looks after the most vulnerable.
"Some parents can do that, but bear in mind: the value of the public dental service is it offers care for the most vulnerable - the ones who struggle to meet the cost - and the ones who really don't have the option of going private."
He said those being left behind "are the people, to start with, with probably the greatest need".
Dentists not being replaced
He said this is down to understaffing and a lack of resources.
"It is becoming very difficult to recruit and retain in the public service," he said.
"There are shortages in dentistry generally; but what's happening is over the years, as dentists retire, in many instances there's no effort made to replace them.
"Obviously the population is increasing, the public service dentists are also looking after special care patients, looking after refugees.
"This has been neglected for many years, but I was shocked when I found that here in Offaly that children as old as 16/17 that's when they're first receiving their first dental exam."
The numbers of practising public-only dentists has dropped by almost one quarter (23%) in the last 15 years.
The IDA has said the HSE need to hire 76 dentists immediately just to bring the service back to that level.
