Temporomandibular Disorder

Procedure

Palpate the lateral pole of the joint just in front of the ear with the mouth closed, then around it as the patient opens slightly. Ask whether any pain is familiar (the pain they came with).

Positive Finding

Familiar pain on palpation of the joint.

Interpretation

Familiar joint pain on palpation or jaw movement, with a history of jaw pain changed by chewing or talking, fits TMJ arthralgia. Refer for medical or dental review if there is trismus with fever or swelling, numbness of the face or chin, a progressive change in the bite, or progressive hearing loss. New headache with scalp tenderness, jaw pain on chewing or visual disturbance in someone over 50 suggests giant cell arteritis: same-day emergency assessment. The Diagnostic Criteria for TMD (DC/TMD) combine the history with examination findings; their published accuracy is for the whole diagnosis, not for one test on its own (Schiffman & Ohrbach 2016 summary). Arthralgia (history of jaw pain changed by jaw use, plus familiar pain on TMJ palpation or jaw movement): 89% / 98%. Myalgia (the same history, plus familiar pain on palpating the temporalis or masseter, or on opening): 90% / 99%. In the original study the reference diagnosis for these pain disorders was made by expert examiners using the same kind of examination, so the figures are shown here as a note, not as test accuracy. The Diagnostic Criteria for TMD (DC/TMD) combine the history with examination findings; their published accuracy is for the whole diagnosis, not for one test on its own (Schiffman & Ohrbach 2016 summary). Arthralgia (history of jaw pain changed by jaw use, plus familiar pain on TMJ palpation or jaw movement): 89% / 98%. Myalgia (the same history, plus familiar pain on palpating the temporalis or masseter, or on opening): 90% / 99%. In the original study the reference diagnosis for these pain disorders was made by expert examiners using the same kind of examination, so the figures are shown here as a note, not as test accuracy.

Procedure

With a ruler, measure pain-free opening, maximum unassisted opening and maximum assisted opening between the upper and lower incisors, adding the vertical overlap of the incisors. Watch the path of opening for deviation, and listen and feel for clicks or grinding.

Positive Finding

Limited opening, deviation of the jaw to one side, clicking or crepitus, or familiar pain.

Interpretation

Limited opening after a history of the jaw locking suggests a disc that has slipped and not returned (disc displacement without reduction). Clicking on its own is common and often harmless. Deviation towards one side usually points to that joint. The Diagnostic Criteria for TMD (DC/TMD) combine the history with examination findings; their published accuracy is for the whole diagnosis, not for one test on its own (Schiffman & Ohrbach 2016 summary). Disc displacement without reduction with limited opening (history of the jaw locking so that eating is difficult, plus assisted opening under 40 mm including incisor overlap) was 80% / 97% against MRI. Clicking alone (disc displacement with reduction) was 34% / 92%: many people with a displaced disc on MRI have no click. The Diagnostic Criteria for TMD (DC/TMD) combine the history with examination findings; their published accuracy is for the whole diagnosis, not for one test on its own (Schiffman & Ohrbach 2016 summary). Disc displacement without reduction with limited opening (history of the jaw locking so that eating is difficult, plus assisted opening under 40 mm including incisor overlap) was 80% / 97% against MRI. Clicking alone (disc displacement with reduction) was 34% / 92%: many people with a displaced disc on MRI have no click.

Procedure

With gloves and consent, slide a finger along the outside of the upper molars towards the back and press upwards behind the last molar.

Positive Finding

Tenderness behind the upper molars.

Interpretation

The lateral pterygoid cannot be reached reliably with a finger, and tenderness here is common in people without TMD, so this is not a useful diagnostic test and is not part of the DC/TMD examination.

Procedure

Ask the patient to bite gently on a tongue depressor between the back teeth, or resist the patient closing (and separately opening and moving sideways) with your hand on the chin.

Positive Finding

Familiar pain in the jaw muscles on resisted movement.

Interpretation

Supports a muscle source of jaw pain. The DC/TMD examination relies on familiar pain on palpating the temporalis and masseter instead.

Procedure

After the patient opens as wide as they can, place your thumb on the upper incisors and index finger on the lower incisors and gently stretch further. Measure the distance and ask about pain.

Positive Finding

Opening that stays limited despite the stretch, with a hard stop; or familiar pain on stretching.

Interpretation

Extra range with a soft stop suggests muscle tightness; a hard limit with little extra range in someone whose jaw has locked suggests a disc problem. Familiar pain on stretching helps confirm a TMD pain disorder. The Diagnostic Criteria for TMD (DC/TMD) combine the history with examination findings; their published accuracy is for the whole diagnosis, not for one test on its own (Schiffman & Ohrbach 2016 summary). An assisted opening under 40 mm (including incisor overlap) in someone whose jaw has locked so that eating is difficult is the DC/TMD criterion for a disc displaced without reduction with limited opening: 80% / 97% against MRI. The number of people without the disorder is not given in the summary, so this is shown as a note. The Diagnostic Criteria for TMD (DC/TMD) combine the history with examination findings; their published accuracy is for the whole diagnosis, not for one test on its own (Schiffman & Ohrbach 2016 summary). An assisted opening under 40 mm (including incisor overlap) in someone whose jaw has locked so that eating is difficult is the DC/TMD criterion for a disc displaced without reduction with limited opening: 80% / 97% against MRI. The number of people without the disorder is not given in the summary, so this is shown as a note.

Procedure

Ask the patient to bite firmly on a cotton roll or tongue depressor placed between the back teeth on one side, which loads the joint on the opposite side. Repeat on the other side.

Positive Finding

Pain in the jaw joint during biting.

Interpretation

Joint pain on loading suggests an inflamed or irritated TMJ, while muscle pain suggests a muscle source. Evidence for this test is limited.