There is ZERO evidence that removal of buccal fat will cure or treat bruxism.
At the moment, there is no cure for bruxism as it can be due to a deep-seated neurological program in the brain. All forms of therapy for bruxism (splints/bite guards, Botox, sleep apnoea management) only manage the peripheral effects such as destruction of teeth and restorations and pain. These treatments aim to limit irreversible damage to the teeth and restorations but will not cure or reduce the frequency at which a patient will brux.