Wisdom tooth pain upon eating does not exclude the possibility of pericoronitis. Wisdom teeth are prone to pericoronitis because of the tendency for food to accumulate in the gingival flap due to incomplete eruption, which induces bacterial infection. In addition, if the wisdom tooth is decayed, or if the decay is severe enough to induce pulpitis, pain may occur when biting. A visit to the dentist will usually clarify the cause.