Dexter announced details of the program Monday at Dalhousie University's dentistry school in Halifax. The government set aside $2.1 million to expand the program in its most recent budget.
"Too many parents are forced to choose between booking a dental appointment for their child and other priorities, including putting food on the table," Dexter said.
"No parent should be forced to make a choice when it comes to the health and well-being of his or her child."
Under the change, children 13 and under will qualify for basic dental care in the province, including annual checkups and cleanings. The current program covers children up to the age of 10.
Dexter said the move will reverse cuts made to children's dental care coverage in 1997 and affect about 40,000 young patients.
"It's one of those programs that we, in opposition, watched get cancelled and now have the opportunity to reinstate."
He didn't rule out expanding the program to include children older than 13 down the road now that his government's books are back in the black.
"We know that there will always be more to do, and we look forward to having the ability to make those kinds of choices."
Dental care coverage for young people varies by province.
Some provinces, including P.E.I. and Newfoundland and Labrador, offer programs similar to Nova Scotia's. Other provinces provide coverage for youth in low-income households and those considered at-risk.
Heather Carr, a local dentist and president of the Nova Scotia Dental Association, said expanding the province's program will ensure more children have access to care at a critical point in their dental development.
"Anything that will get children in to see their dentist and have their teeth checked and have early problems detected is a wonderful thing," she said.