The percussion test is a helpful test to diagnose if any teeth present with periapical inflammation.
Before you begin: select which teeth you will be testing.
It is helpful to test 3-4 teeth at a time: a tooth on the opposite side of the mouth from the symptomatic side/tooth, a tooth on either side of the tooth of interest, a tooth opposing the tooth of interest, and the tooth of interest.
Every situation is different, so you will need to adjust your selection based on your patient’s symptoms and natural dentition
Ideally try to select control teeth that have similar anatomy or restorations (consider crown materials, size/location of restorations) to the tooth of interest
Give each tooth a number and ask your patient to compare “tooth number 1, 2, and 3” at the conclusion of the test
It is recommended to end with the tooth of interest in case there is lingering discomfort
Explain the procedure to your patient. Their participation is necessary for accurate interpretation of results. Be sure to instruct your patient to raise their hand when they feel tenderness or pain.
For example, you could say: “I am going to tap on a few of your teeth now. If you feel any pain or discomfort when I tap a tooth, raise your left hand and I will stop tapping on the tooth.”
You can start percussion on a tooth you suspect is healthy to gain patient confidence/trust in the test.
First, apply pressure on the tooth that has been selected to be percussed with a gloved finger. If the tooth is sensitive, tender, or painful, do not continue with the rest of the percussion test.
Using the blunt end of an instrument, such as the handle of a mirror, gently tap the incisal or occlusal surface of the selected teeth in an axial (vertical) and horizontal direction. As you tap, begin lightly and gradually tap with slightly more force.
If the patient feels tenderness in a tooth in an axial direction, you should not continue tapping on that tooth. Though percussion tenderness is not itself diagnostic of endodontic pathosis, it's presence keeps this in the differential.
If the patient reacts only to horizontal percussion, the diagnosis is less likely to be an endodontically involved tooth and more likely to be due to a periodontal cause.
Remember that neighboring teeth to the diseased tooth may also express some tenderness to percussion, though the tenderness is typically milder if present.
As you tap the selected teeth, listen to the sound the tapping creates and compare the sound to the tapping of other teeth.
Metallic tone on percussion classically indicates intrusively luxated teeth or ankylosis (which typically requires decoronation)
Record the results in a record keeping table.
Repeat this test until all control teeth and the tooth of interest have been tested.
Torabinejad M, Fouad A, Shabahang S. Endodontics: Principles and Practice. 6th ed. London, United Kingdom: Elsevier, 2020.
Blicher B, Pryles RL, Lin J. Endodontics Review: A Study Guide. Hanover Park, IL: Quintessence Publishing Co, Inc, 2019.