Dummies promote a greater flow of saliva than thumbs or fingers, which helps to prevent tooth decay (provided they are not dipped in juice or honey), and are less likely to cause deformity because children tend to give up dummies sooner, before the development of the adult teeth. Thumb- sucking tends to persist beyond when the adult teeth have started to develop, and can lead to buck teeth (protruding incisors), or other problems depending on which finger is sucked.
Dr Ronnie Levine, scientific adviser to the Health Education Authority, says the sucking of dummies is far more common than thumb-sucking in babies but declines rapidly with age and is rare over the age of three. Thumb or finger-sucking is less common in babies but more common after 18 months and more persistent than dummy-sucking. Four out of ten thumb-suckers still do it at the age of nine.
Writing in today's edition of the British Dental Journal, Dr Levine says 95 per cent of children indulge in what scientists call non-nutritive sucking.