Medical experts are urging people to be cautious about having their teeth veneered, ahead of National Teeth Care Day on Monday.

Veneered teeth have recently become popular among young people and office workers whose teeth have become discolored by coffee and cigarettes.

But there are strict criteria for veneer teeth, and not everyone is suitable, warn doctors.

Veneer teeth are thin porcelain shells that are bonded onto the front of teeth for a better appearance.

Dr Wang Ying, from Shanghai Ren'ai Hospital, said veneer teeth is a whitening and cosmetic technology, typically used for people whose teeth are chipped, discolored or slightly misaligned.

"But doctors must remove the outer layer of enamel," he said. "It is an irreversible injury to teeth, so we only suggest veneer teeth when a patient's benefit is bigger than the injury to their enamel.

"Doctors should carry out a careful check and evaluation of patient' teeth when suggesting such service."

She said people must visit licensed hospitals and clinics for consultation on veneer teeth.

Even with veneer teeth, proper dental care and regular visits to the dentist are necessary to ensure teeth safety, she added.

Experts reiterated the importance of good, proper dental care and hygiene habits, as a recent epidemiological study found 97 percent of the adult population have dental calculus, 88 percent have decayed teeth and 85 percent have gum issues.

Along with sensitive teeth, bad breath, teeth stains and dental plaque, these are the seven common dental problems among Chinese adults.

Dr Wang Ying from Shanghai Ren'ai Hospital checks a female patient.