Schools and nurseries are being called on to help check children have brushed their teeth as health officials warn youngsters as young as three are suffering from severe tooth decay.
The National Institute for Health and Care Excellence has urged local authorities to "act now to stop the rot"
It warned that young children and frail older people were most at risk from preventable problems such as tooth decay and gum disease.
Professor Mike Kelly, the director of the centre for public health at Nice, said: "Children as young as three are being condemned to a life with rotten teeth, gum disease and poor health going into adulthood.
"Many children have poor diets and poor mouth hygiene because there is misunderstanding about the importance of looking after children's early milk teeth and gums.
"They eat too much sugar and don't clean their teeth with fluoride toothpaste. As a society we should help parents and carers give their children the best start in life and act now to stop the rot before it starts."
Prof Kelly said there are wide regional differences in oral health, and said the situation is "bleak for many adults as well as children in disadvantaged areas".
He added: "Diet, poor oral hygiene, smoking, alcohol and a lack of understanding about oral health are causing tooth decay, gum disease, tooth loss and increasing the risk of mouth cancers. These are also the risk factors causing many chronic conditions, including heart disease and diabetes."
Nice suggests local authorities consider supervised tooth-brushing and fluoride varnishing programmes in nurseries and primary schools in areas where children are at high risk of poor oral health.