Temporary dental crowns are usually cemented into place using "temporary" cement so they can be removed easily when it is time to cement the permanent crown on. Because this cement is not as strong as other types of dental cement, you should take some precautions so not to dislodge your temporary crown.
Some of these precautions are to minimize the usage of the side of your mouth that has the temporary crown. As much as possible, shift the bulk of your chewing activities to other areas and keep sticky foods away from the temporary dental crown. Anything sticky (caramel, chewing gum, etc...) has the potential to grab onto the temporary crown and pull it off its tooth. Avoid chewing hard foods with the temporary dental crown. Chewing exceptionally hard foods can dislodge or break your temporary.
A tooth with a temporary dental crown can usually be brushed and flossed in normal fashion, with the following consideration. After flossing it may be best to remove the dental floss by way of letting loose of one end and then pulling it out to the side. Pulling the floss back out in normal fashion might snag the temporary crown and pull it off its tooth.