The surgery has been closed.
Dozens of children are believed to have been put at risk after being exposed to drain cleaning fluid at a public dental surgery in County Clare this week.
The Health Service Executive (HSE) is trying to contact all of those who had been affected by the mix-up at Ennis Health Centre, according to the Irish Mirror.
It said that early indications suggested that water at the clinic had been accidentally mixed with drain cleaner instead of a dental fluid.
This water was then used to clean dental equipment.
It's believed that patients at the clinic were exposed to the diluted drain cleaner on Wednesday and on Thursday of this week, when the error was spotted.
Sixteen of the children who were affected sought medical advice after feeling unwell, the HSE told RTÉ.
One upset parent said she had contacted the clinic when her son's mouth was burnt after treatment there on Wednesday, but only found out about the cleaning fluid when the story broke in the media.
"I'm very angry," she told RTÉ Radio 1's Drivetime. "I do think it would have helped a little if I had been contacted personally first of all.
"It is upsetting. It could have been a lot worse for my child and all of the other children who have been affected by this."
The HSE has apologised and said it was investigating the incident.
"This is so regrettable and unfortunate," said chief officer of the HSE Mid West Bernard Gloster. "I want to apologise for any concern or upset caused to the children and their families.
"We are taking all of the necessary steps to ensure they are supported and have adequate information. We will be conducting a full review to establish all of the facts.
"I am grateful to all of our management staff and clinicians who worked very hard late into last night to respond to this incident."
