A new fleet of dental vans will start visiting primary schools across the state, starting from next term, with Wodonga one of the first four areas chosen.

Staff will provide free check-ups and treatment including root canals, fillings, teeth cleaning and fluoride applications.

All students will receive a free dental pack with a toothbrush and information.

The state government says the program will lower dental costs for families by $400 per student.

Premier Daniel Andrews said the full fleet of vans, known as the Smile Squad, would be operational by 2022.

About 500 dentists, oral health therapists and dental assistants will be employed to staff the vans.

"We're making sure school students have a bright and healthy smile and we're helping hard-working families save on costly dental bills, as we promised we would," he said.

"Kids' oral health is so important, but busy families can often struggle to find the time to get to the dentist.

"We're fixing that."

The budget will provide $321 million for free dental care, including the dental vans.

According to the government, oral disease is one of the most common and expensive diseases to treat, but is amongst the most preventable diseases.

One quarter of all Australian children have untreated tooth decay.

Dental issues are the biggest cause of preventable hospitalisations for those under 10 in Victoria.

Health Minister Jenny Mikakos said it was a necessary program.

"Our kids deserve the best start in life, and good oral health is important to lay the foundations for good lifelong health and well-being," she said.

"Tooth decay is preventable, but we all know dental bills hit the hip pocket hard.

"That's why our free dental care in public schools program is so important."

The vans are expected to service 650,000 students each year.

The government also expects to free up more than 100,000 places for adults in the public dental system each year and reduce waiting times.

Public dental care is available for Victorian children aged up to 12 years, but less than 20 per cent of eligible children take it up.