My daughter is getting dental treatment by fixing...

can the dental implant cause your jawline to be misaligned ?
yes sure that dental implant cause your mouth, jaw to be misaligned but dosent mean that the implant isnt will placed . 
the teeth brace is usually placed due to misaligned jaws and to reposition the location of the teeth 
what are other possible causes for jaw to turn the other side ?

• facial nerve palsy usually due to an infection or a flue 
• meningitis 
• brain infection 
• brain tumor 

what are the diagnostic tests needed ?
the doctor is goning to check the patients history and do a clinical examination , do a brain MRI to rule out the any brain infection of tumor, do an electromayography and a CAT scan for the upper and lower jaws  
what is our advice ?
you should go back to the dentist to restore the brace in case your child really needs it from the dentist point of view and pay a visit for the pediatrician for the right diagnosis and the correct treatment