for redness, swelling or deformity. Finally, the teeth are examined. Each tooth that may be painful is percussed (tapped), palpated at the base of the root, and probed with a dental explorer for dental caries and a periodontal probe for periodontitis, then wiggled for mobility. Sometimes the symptoms reported in the history are misleading and point the examiner to the wrong area of the mouth. For instance, sometimes people may mistake pain from pulpitis in a lower tooth as pain in the upper teeth, and vice versa. In other instances, the apparent examination findings may be misleading and lead to the wrong diagnosis and wrong treatment. Pus from a pericoronal abscess associated with a lower third molar may drain along the submucosal plane and discharge as a parulis over the roots of the teeth towards the front of the mouth (a "migratory abscess"). Another example is decay of the tooth root which is hidden from view below the gumline, giving the casual appearance of a sound tooth if careful periodontal examination is not carried out. Factors indicating infection include movement of fluid in the tissues during palpation (fluctuance), swollen lymph nodes in the neck, and fever with an oral temperature more than 37.7 °C. Investigations Any tooth that is identified, in either the history of pain or base clinical exam, as a source for toothache may undergo further testing for vitality of the dental pulp, infection, fractures, or periodontitis. These tests may include: Pulp sensitivity tests, usually carried out with a cotton wool pledget sprayed with ethyl chloride to serve as a cold stimulus, or with an electric pulp tester. The air spray from a three-in-one syringe may also be used to demonstrate areas of dentin hypersensitivity. Heat tests can also be applied with hot Gutta-percha. A healthy tooth will feel the cold but the pain will be mild and disappear once the stimulus is removed. The accuracy of these tests has been reported as 86% for cold testing, 81% for electric pulp testing, and 71% for heat testing. Because of the lack of test sensitivity, a second symptom should be present or a positive test before making a diagnosis. Radiographs utilized to find dental caries and bone loss laterally or at the apex. Assessment of biting on individual teeth (which sometimes helps to localize the problem) or the separate cusps (may help to detect cracked cusp syndrome). Less commonly