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1565 Hollenbeck Ave, Suite 106, Sunnyvale, CA 94087(669) 234-2354
Silicon Valley Endodontics and Microsurgery
The Diagnostic Process

How We Diagnose
a Toothache

A specialist endodontic evaluation is built around a series of focused tests. Each one tells us something different. None of them, on its own, is enough. Here is what we are doing during your appointment, what each test reveals, and why we always use several together.

Medically reviewed by Dr. Jason Kung, DDS, MS · Specialist Endodontist · UCLA DDS · OHSU MS ·
Schedule a Consultation (669) 234-2354

Patient Education

How CBCT helps us find the source of your pain

A short video from the American Association of Endodontists on how 3-D cone-beam imaging reveals what 2-D X-rays can miss.

How 3-D cone-beam imaging lets your endodontist see what 2-D X-rays miss — and why that matters for your diagnosis.Video courtesy of the American Association of Endodontists.Watch on its own page

Test 1 of 7

Cold Test

What it is

We touch a small piece of cold cotton (or refrigerant spray on a cotton pellet) to the tooth for a few seconds. The same test is performed on a neighboring healthy tooth and a tooth on the other side of the mouth as controls.

What it tells us

A normal tooth feels a brief, sharp sensation that disappears within 1–2 seconds. A tooth with reversible inflammation feels exaggerated cold but recovers. A tooth with irreversible pulpitis aches for 30 seconds or longer after the cold is removed. A tooth with no response usually has a dead nerve. The cold test is the single most useful pulp test we have.

Why one test isn't enough

Cold tells us the state of the pulp itself. It does not tell us whether the surrounding bone is infected or whether the pain has another cause.

Test 2 of 7

Electric Pulp Test (EPT)

What it is

A small probe delivers a tiny electrical current to the tooth. You hold a metal handle and let go when you feel a tingling sensation. The number on the device tells us at what threshold you responded.

What it tells us

It confirms whether the nerve fibers inside the tooth are alive. The EPT is most useful as a backup when the cold test is unclear — for example, in a tooth with a full crown where cold may not transmit well, or in a recently traumatized tooth where the response can change day to day.

Why one test isn't enough

EPT only tells us the nerve is alive — not whether the pulp is healthy or inflamed. A tooth can give a normal EPT response and still need a root canal.

Test 3 of 7

Percussion Test

What it is

We gently tap on the chewing surface of each tooth with the back end of a dental mirror handle and ask whether any feel different from the others.

What it tells us

Tenderness to percussion is a reliable sign that the ligament around the tooth is inflamed — usually because of an infection that has spread out of the tooth into the surrounding bone, or because of a cracked tooth, recent trauma, or sinus involvement.

Why one test isn't enough

Percussion tells us about the ligament around the tooth, not the pulp inside. A tooth can be percussion-negative but still have a dying pulp, or percussion-positive for non-endodontic reasons.

Test 4 of 7

Palpation Test

What it is

We press firmly with a finger on the gum and bone in the area above (or below) the root of the suspect tooth and compare it to the surrounding areas.

What it tells us

Tenderness on palpation usually means there is inflammation or an abscess that has reached the outer surface of the bone. It often correlates with a swelling that may or may not be visible.

Why one test isn't enough

Palpation is most useful for confirming what other tests are already pointing to and for finding the exact source of a swelling.

Test 5 of 7

Bite Test

What it is

We have you bite down on a small plastic device (a Tooth Slooth) one cusp at a time. We ask you to release suddenly and tell us whether the pain comes from biting down, from releasing, or both.

What it tells us

Pain on biting down often suggests inflammation of the ligament. Sharp pain on release is the hallmark of a cracked tooth — it is one of the most diagnostic tests we have for cracks. Performing it on each cusp separately tells us which part of the tooth is fractured.

Why one test isn't enough

The bite test is highly specific for cracked teeth and ligament inflammation but does not tell us about the pulp's state.

Test 6 of 7

Transillumination

What it is

We shine a bright fiber-optic light directly through the tooth in a dark operatory.

What it tells us

Healthy enamel transmits light evenly. A crack blocks the light and shows up as a dark line, while a chunk of tooth that is fractured off may light up brightly while the rest stays dim. Combined with magnification, transillumination is one of the best ways to see cracks that are invisible to the naked eye and to standard X-rays.

Why one test isn't enough

Transillumination finds cracks but doesn't tell us how deep they go — that requires the bite test, the microscope, and sometimes CBCT.

Test 7 of 7

J. Morita Veraview X800 CBCT (Endo Mode)

What it is

Cone-beam computed tomography is a focused 3D X-ray that captures a small volume of your jaw in true three dimensions. We use the J. Morita Veraview X800 — widely regarded as the best dental CBCT for endodontics — in its high-resolution Endo Mode (80 µm voxel size, 40 × 40 mm limited field of view focused on a single tooth or sextant). This is the small-volume, high-resolution protocol the AAE/AAOMR Joint Position Statement on the Use of CBCT in Endodontics (2015) recommends, and it keeps the radiation dose to a small fraction of a full medical CT.

What it tells us

Endo Mode CBCT shows things 2D X-rays simply cannot — extra root canals, vertical root fractures, the true extent of resorption lesions, the relationship of the root tip to the sinus or to a major nerve, and small areas of bone loss that are still hidden on standard films (Patel et al., European Society of Endodontology Position Statement, IEJ 2019).

Why one test isn't enough

CBCT is reserved for cases where the standard tests and 2D X-rays leave the diagnosis unclear, or where surgical planning requires a 3D view. We don't use it on every patient — only when the answer it provides will change the treatment, consistent with the AAE/AAOMR position statement.

Putting it together

A diagnosis is the combination of symptoms (what you are experiencing), signs (what we find on testing), and imaging (what we see on the X-ray and CBCT). Each test answers a slightly different question, and they sometimes contradict each other — which is itself important information.

For example, a tooth that responds normally to cold but is exquisitely tender to percussion almost certainly does not need a root canal — the pulp is alive and healthy, but the ligament around the tooth is inflamed, often from a high bite or a recent filling. A tooth that doesn't respond to cold and shows a dark area on the X-ray almost certainly does need a root canal — the nerve is dead and infection has reached the bone.

By the end of your appointment we will tell you the diagnosis in plain language — for example, "the nerve in this tooth is dying and there is early infection at the root tip" — what your options are, what each option costs in time and risk, and what the realistic outcome is. Only then do you decide whether to proceed.

The diagnostic framework described here is consistent with American Association of Endodontists position statements and standard endodontic teaching, including the diagnosis chapter in Endodontics Review: A Study Guide (Blicher, Lucier Pryles & Lin, Quintessence, 2016).

Want a thorough evaluation, not a guess?

A specialist endodontic consultation includes the full battery of tests above plus 2D imaging — and CBCT if needed. You leave knowing exactly what is wrong, whether it can be saved, and what the realistic outcome is.

Schedule a Consultation(669) 234-2354

Related: When tooth pain isn't from your tooth · Our technology

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