Crowding of teeth simply describes a condition where there is not enough space in the mouth (on the upper and / or lower jaw) for the normal number of adult teeth, i.e. the teeth are actually too large for the jaw. Tooth crowding is regarded as a 'malocclusion', in other words a misalignment of the teeth.
It is thought that tooth crowding can be caused by a range of factors. Whilst genetics is the prime cause some early childhood behaviours such as thumb sucking, dummy/pacifier use beyond the age of three and continued bottle-feeding are considered other potential causes. Extra teeth, unusually shaped teeth and impacted teeth may also cause the condition, as well as problems with existing dental work, particularly if badly fitting.
Although crowding may be noticed at a young age – even in children as young as six – crowding may get worse with age, since adult teeth will require even more room. Crowding can also be implicated in other conditions such as tooth decay and gingivitis, and even periodontal disease.
The opposite condition to crowding is called 'spacing', where there is too much room on the jawbones for the normal set of adult teeth.
Orthodontic treatment can correct issues with both tooth crowding and tooth spacing.