4 year old,birthday in december

My son like in the description 4 years old, birthday in December lost a front tooth (top) a couple days ago and now I noticed his other top front tooth is loose. Mind you, I'll be calling the dentist on Monday to make an appointment..hes had dental surgery because of cavities (which is so weird since I brush his teeth a lot and also not a bunch of sugars) but anyone else's 4 year old lose a front tooth? I know it's usually the bottom tooth but nope...not for Josiah!