People with untreated bite problems, heavily restored teeth, badly broken-down teeth or advanced gum disease are at higher risk for dental infections and are therefore more likely to experience mouth swellings. People with compromised immune systems are also at higher risk for developing mouth infections and therefore swelling. People with an ill-fitting denture may develop swelling where the denture rubs. People with untreated bite problems may also traumatize their cheeks and tongue resulting in swelling. Less commonly, diseases such as Sjogren’s Syndrome or mumps may lead to swelling in the mouth.