Hi.. Welcome to HCM.. As per your complain Citalopram does not cause dental cavities directly, however they have a tendency to cause dry mouth that inturn cause cavities.. Due to reduced flushing of the debris from mouth caused due to reduced saliva flow can aggravate bacterial growth and can cause decay in teeth.. You should first of all get the decay removed and teeth filled to prevent further damage to teeth due to decay.. Avoid excess of sugary and sticky foods.. Always gargle after eating anything.. Drink ample of water.. -For dry mouth chew sugarfree chewing gums.. -Drink plenty of water. -Avoid regular mouthwash and use specialized mouthwash that are formulated for dry mouth patients like Biotene.. -You can also instil artificial saliva drops.. -Suck tart candies as it also stimulates saliva flow.. If does not improve consult an Oral Physician and get evaluated.. Hope this helps.. Regards,