Hi Cindy,
Frequently the purpose of a bite splint is to change the bite. That would be the case of a repositioning splint and functional jaw orthotic, etc. The bite often needs to change to "fix" the TMJ problem. The muscles do not like the way the teeth come together so they are rebelling (spasms, pain). In these cases, there usually are phases of treatment - Phase 1 being the splint and Phase 2 permanently fixing the bite with crown, overlays, bridges, braces, etc. There is usually a Phase 3 also but I am unsure what they do at that point (maybe retainers or follow-up visits?)

You need to ask your dentist what his/her goal is for the splint once the pain is under some sort of control. So, to answer your question - yes, the bite can change when wearing a splint (but find out why and what's going to be done about it).

God bless...
Carol