Pericoronitis is a common problem in young aults with partial tooth impactions. It usually occurs within 17 to 24 years of age as it is when the third molars start erupting. It occurs when the tissue around the wisdom tooth has become infected because bacteria have invaded the area. Poor oral hygiene and mechanical trauma on nearby tissue can cause this inflammation. Food impaction and caries (tooth cavity) are also problems associated with third molar pain.