There must be enough room for the wisdom tooth to erupt or enter the mouth. An impacted wisdom tooth is one that fails to erupt properly into the mouth and becomes stuck, either under the gum or as it pushes through the gum. If there is enough space in the mouth, the wisdom tooth may not become impacted and will erupt and function normally. People can have problems with both impacted and non-impacted wisdom teeth. Some of these issues can result in symptoms such as pain and swelling; however, other wisdom teeth may not cause any symptoms but still cause problems in the mouth.