British people have healthier teeth than Americans, you’re mistaking the results of invasive and often damaging cosmetic dental procedures with the actual function and health of the teeth.
Brits statistically have healthier teeth than Americans. Not whiter or straighter for those who can afford it, but healthier.
Modern British dentists perform orthodontic and teeth whitening treatments just as American dentists to, responding to customer demand. It’s worth noting that elective cosmetic dentistry is paid for in the UK, it’s not free — and the demand comes for straight white teeth comes from people watching films and TV. Although the NHS does provide orthodontic treatment if there is real medical need (as opposed to cosmetic).
The majority of dentistry is paid in the UK. Fillings, extractions and everything that isn’t a straight clean or absolutely required (ie; fighting infections)