Dashes and Parentheses
Dashes and Parentheses are both used to show an interruption in thought or some kind of aside. Dashes are more emphatic. Parentheses are normally paired. Both should be used sparingly or they become a distraction. Parentheses also have a few special uses.
Dashes with Nonrestrictive Modifiers
Parentheses with Certain Numbers and Letters
Punctuation Inside Parentheses