Sending teenagers text message reminders could improve their tooth brushing habits, a trial has found.

However brushing more did not tackle levels of decay, with researchers calling for secondary school pupils to be better educated on oral health.

For the study, known as the Bright trial, experts from the universities of Sheffield, Cardiff, Leeds, York and Dundee checked the teeth of 4,680 children aged 11 to 13 from 42 schools.

The analysis included 2,383 pupils, half of whom had one 50-minute lesson with their teacher about oral health, along with twice-daily text messages about toothbrushing.

Researchers found the measures had a positive impact on the youngsters’ toothbrushing behaviours after six months, but did not reduce the number of cavities or the levels of tooth decay.

However, there was evidence the lesson and text messages could be beneficial to pupils from low income families, according to researchers.

Professor Zoe Marshman, of the University of Sheffield’s School of Clinical Dentistry, co-led the Bright trial.

She said: “Pupils who received the lesson and text messages reported brushing their teeth more often after six months, but did not have less tooth decay or plaque after two and half years.

“Pupils eligible for free school meals, however, may have benefited more than others suggesting a potential for the programme to reduce inequalities in oral health.”

In February, figures from the Office for Health Improvement and Disparities (OHID) revealed there were 47,581 tooth extractions in NHS hospitals in England for patients aged 0 to 19 last year.

Some 66% of extractions – or 31,165 – were down to a primary diagnosis of tooth decay, up 17% from the previous 12 months.

Tooth decay remains the most common reason for youngsters aged five to nine being admitted to hospital.

Last year, hospital admissions for childhood tooth extractions cost NHS hospitals £64.3 million, with decay-related extractions costing £40.7 million.

Prof Marshman added: “Tooth decay and all its negative consequences such as toothache, loss of sleep and problems eating are very common in children of secondary school age.

“While school-based initiatives for children between the ages of 4-11 have been delivered for decades, there is very little for secondary schools.

“However, this is a critical stage for toothbrushing practices to become an established behaviour for adulthood.

“This is why it is vital to help young people to improve their understanding of the importance of toothbrushing and skills to prevent tooth decay.”

Eddie Crouch, chairman of the British Dental Association, said: “Decay and deprivation go hand in hand, and innovative work like this can help shift the dial.

“Ministers say they want to move from treatment to prevention, and dentistry is uniquely placed to deliver on that ambition.

“Closing the oral health gap means restoring access to care and putting tried and tested preventive programmes to work.”

James Colliver, lead learning manager at Outwood Academy City in Sheffield, which took part in the Bright trial, said: “We have a lot of students losing their teeth so I felt it was definitely worthwhile.

“One of the girls, aged 12, who was in the class told me she’d already had eight teeth out, so that made it feel like this was really important.”

The Bright trial is funded by the National Institute for Health and Care Research (NIHR) and the findings of the study have been published in the journal of Health Technology Assessment.