This problem is knwn as bruxism
or night grinding of teeth. It happens unconsciously when patient is sleeping reasons for this problem. Can b either tmj
problem or over stress.
Yes it will affect your teeth as a result their will b more wearing of tooth enamel surface. Leading to sensitivity of your teeth.
Treatment for this problem is as far the teeth r concerned. Night guards. Patient is supposed to wear this guard during sleep to prevent further grinding of teeth.