The practice, if done badly, can increase decay and mean more fillings are needed in other teeth, researchers said.
Dental fillings may do more harm than good, as trauma caused by the initial filling could make neighbouring teeth prone to infection and decay, experts have warned.
The practice, if done badly, can increase decay and mean more fillings are needed in other teeth, researchers said.
A new study showed some dentists are more likely than others to have patients who develop new decay after a filling.
"This study highlights the fact that dental intervention can cause more harm than good," said Damien Walmsley, spokesman for the British Dental Association.
The study found six out of 10 teeth which were next to a filling had also decayed after five years. Almost 30 per cent of these needed filling, the 'Telegraph' reported.
"Once a dentist has gone into a tooth, they may accidentally damage another tooth. Dentists need to keep up to date with the latest techniques to ensure they don't damage other teeth when they do a filling," said Walmsley, who is also a dental expert at the Birmingham University.
The experts stressed that patients should have fillings, as there is no other solution when teeth are decayed to the extent they need replacement.
However, dentists must be careful with their approach, using "minimal intervention" to reduce the chance of damaging teeth, they said.
According to experts, patients needed to be particularly careful about taking care of their teeth after a filling, reducing sugar intake and brushing properly.
"It is highly possible that the intervention by the dentist causes a problem in adjacent teeth. Fillings are not an ideal solution but at the moment it's the best solution we have," said Simen Kopperud, of the Nordic Institute of Dental Materials in Oslo, Norway, who led the study.
The study was published in the Journal of Dentistry.