You should get your cracked tooth treated asap. Visit a dentist and first get an Xray done to see if the crack has reached the roots or not. If the crack is just superficial then composite restoration will do but if it has cracked till the roots then you need to undergo RCT and capping. So, my take home advise is to first visit a dentist. For more info on cracked tooth visit the link...http://www.identalhub.com/article_what-are-the-advantages-of-composite-filling-58.aspx