This usually happens as the nerves are connected to each other, may be it ddoes not realiza at the time of incident but it does happen or hurts after some point of time, you should go for full check up and find it out.
Head injury as such may not have effect but some times due to fall the teeth takes the impact but there are no visible sign or symptoms but over the time like after couple of months or year the teeth which gets effected may start turning black due to the trauma. Some times due to the traume the teeth get cracks which can not be diagnosed very easily at that time but can bother afrer wards . That is called cracked tooth syndrome. If you want to know more about cracked tooth you can browse the following link.......www.identalhub.com/articlecategory-cracked-tooth-56.aspx
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