Opposition parties say more should be done to increase access to NHS dentists.
But the Welsh government insists there have been real improvements in recent years.
It said 34,000 more patients were seeing a dentist at the end of last year compared to two years previously.
The figures show that 52% of adults in Wales were treated by a dentist in the 24 months before 31 December last year.
But Plaid Cymru said the fact that almost half of adults had not received any treatment highlighted a problem with the number of available NHS dentists.
Health spokeswoman Elin Jones said: "It's obvious from the number of people who are still unable to find an NHS dentist, even for children, that we need to increase the NHS capacity even further."
Liberal Democrat assembly member, Eluned Parrott, added: "This Welsh Labour government has completely overlooked the dentistry service in Wales.
"Just stating that everyone should have access to a dentist isn't enough - there has to be action too."
How do you provide enough dentists to meet the demand?
Cardiff University's School of Dentistry is playing an important part, both in training future dentists and helping people who struggle to get seen on the NHS.
Students visit an outreach clinic in Mountain Ash, Rhondda Cynon Taf - an area with one of the highest rates of dental disease in the UK.
When the clinic opened two years ago, over 1,000 patients tried to sign up in a week.
The students benefit from being able to treat, with some supervision, complicated cases which they might not have come across in Cardiff
Patients get free dental treatment in an area where dentists are still in short supply.
Prof Mike Lewis, the Dean of Cardiff University's School of Dentistry, said he believes there are now enough dentists to meet demand.
"The days of seeing people queued up outside practices are gone," he said.
"I think the workforce is out there actually. I think at the present time, if somebody wants dental treatment they will get it."
But Brian Webber, who helps train new dentists, said there are not enough places for them to practise.
"In the old days you could graduate and go and set up anywhere but now you have to go where there's a contract," he said.
"And if the local health board doesn't have a contract available then the dentists can't work there.
"They could go into a private practice but that's not always available everywhere, especially in Wales.
"We don't have a huge pot of money and so we have to manage the resources we have got effectively."
The Welsh government said more dentists are now working in the NHS in Wales - 1,392 compared to 1,186 dentists in 2006/07.
It said that access to dental services continues to improve, with 1.7 million patients regularly seeing an NHS dentist last September- more than 34,000 higher than in September 2011.
"For the first time, every health board in Wales has a dedicated Local Oral Health Plan to measure the effective delivery of dental services and promotion of good oral health over the next five years," the Welsh government added.
Almost half of adults in Wales have not seen a dentist in the past two years, according to the latest Welsh government statistics.