Regarding your problem, definately you need Root Canal on the teeth which are moving and mobile teeth donot get stablised by themselves if the mobility is more because of repeated mastication trauma during chewing of food or during swallowing. So you have to get the splinting done to stablise them. The splinting has to be done for minimum 3 weeks and if they are stable by then, splinting will be removed. For understanding Root Canal Treatment you can read the following.... Root Canal Therapy