Sir, in our overview of 40 years of surveys of Children's Dental Health,1 we reported that 33% of 15-year-old children had permanent teeth extracted because of decay in 1973, reducing to 24% in 1983, and then to 7% in 1993. It has remained near to that figure for the last 20 years.

The proportion of 15-year-olds undergoing extractions as part of orthodontic treatment ranged from 21–26% between 1973 and 2003.2,3 We examined the raw data, recently made available, of 2,415 15-year-old children from the 2013 survey of England, Wales and Northern Ireland.4 Fifteen percent of 15-year-olds in England had had at least one tooth extracted as part of orthodontic treatment, compared with 16% in Wales and 21% in Northern Ireland. The teeth most commonly extracted were: upper first premolars (8.9%), lower first premolars (4.1%), and upper and lower second premolars (3.8%). Less than 1% of first permanent molars were extracted for orthodontic reasons. In England and Wales, 7% of 15-year-olds had four teeth extracted, 6% had two teeth extracted and 2–3% had one tooth extracted.

In our previous paper,1 we did note the problems with analysing trends due to changing methodologies in the surveys but that for 12- and 15-year-olds, the impact was likely to be minimal. It does therefore appear that the proportion of 15-year-olds who have had extractions for orthodontic treatment has decreased over the last ten years, despite a relatively constant number of 12-year-olds undergoing orthodontic treatment at the time of the survey (8-9%) and an increase in the number of 15-year-olds under treatment from 14% to 18%.3,4