"Of the 33 who had been identified as having inadequate follow-up, five were found to have suffered greater decay, which has since been treated," he said.
The extra dental work those five youngsters received involved fillings of greater depth than they had first received.
A dental paediatric specialist and a public health dentistry specialist from University of Otago were commissioned by the board to review the cases of 33 children, who had been examined between October 2010 and April 2012.
He said the specialists recommended individual follow-up care plans and regular frequent reviews for each child.
The two dentists will continue to support the WDHB with additional quality checks and reviews over the coming months. Mr Walden said the WDHB was assuring parents and the community that it took the safety and quality of its services very seriously "and, as such, are doing everything possible to ensure any resulting harm is kept to a minimum".
"We have not taken this lightly and have undertaken a review of our processes. We will be auditing the service more frequently to identify any potential problems early, and to reduce the chances of this happening again," he said.
He said staff had contacted or met the parents of the five children most affected to discuss what occurred, the board's initial response, and the details relating to the care of each of their children.
"The WDHB is committed to open and honest disclosure when the service provided is below the standard of care our children deserve. We are also communicating with the parents, schools and surrounding dentists associated with any children examined during this time."
Mr Walden said the practitioner concerned had ceased clinical practice and was no longer employed by the WDHB.
If any parents have any concerns, they can call 0800 DENTAL (0800 336 825), Monday to Friday, 8am-5pm.
