The brace is fixed to the teeth with a glue that is strong enough to withstand most chewing, but weak enough to be able to be removed without damaging the enamel. Any damage to the teeth and surrounding gums are generally caused by not looking after your braces properly i.e. not cleaning well enough and eating/drinking things we recommend you should avoid. This can include decalcification (damage to the enamel causing permanent marks) or gingivitis (swollen, bleeding gums) or caries (tooth decay). Tooth roots also get slightly shorter during treatment, but usually it is almost undetectable. If these problems continue then we would advise you to stop the orthodontic treatment to save the health of your teeth.