Conditions We Treat
Plain-English guides to the dental conditions an endodontist diagnoses and treats. Each page covers the warning signs, how the condition is diagnosed, and the treatment options Dr. Kung considers in our practice.
Cracked Tooth
A cracked tooth is a fracture that begins on the chewing surface of a tooth and runs vertically toward the root. Most cracks are too narrow to see on a regular X-ray, but they let bacteria reach the dental pulp and irritate the surrounding ligament — producing a very recognizable pattern of symptoms.
Pulp Necrosis (Dead Tooth Nerve)
Pulp necrosis means the soft tissue inside a tooth — the pulp, made up of nerves, blood vessels, and immune cells — has lost its blood supply and died. A necrotic tooth no longer feels temperature, but the bacteria left behind can leak out the root tip and infect the surrounding bone.
Irreversible Pulpitis (The Toothache That Won't Stop)
Irreversible pulpitis is the stage of pulp inflammation past which the tissue can no longer recover, even if the irritant (a deep cavity, a leaking crown, a fractured filling) is removed. It almost always progresses to pulp necrosis if untreated, and it produces a pain pattern that is so distinctive it is one of the most reliable diagnoses in dentistry.
Dental Abscess (Periapical Abscess)
A dental abscess is a localized collection of pus that forms at the tip of a tooth's root when bacteria from a necrotic pulp escape into the surrounding bone. The body's immune system mounts a powerful response, and the pressure produces some of the most severe pain in clinical medicine.
Root Resorption (Internal & External)
Root resorption is the dissolving away of root structure by specialized cells called odontoclasts. Internal resorption begins inside the root canal; external resorption begins on the outer surface of the root. Both are usually painless in the early stages and most often discovered incidentally on routine X-rays.
External Root Resorption
External root resorption is the breakdown of root structure that begins on the outer surface of the root and works inward. It is driven by specialized cells called odontoclasts that have been stimulated to attack the cementum and dentin from the outside. Most early-stage external resorption is painless and discovered incidentally on a routine X-ray — by the time symptoms appear, a significant amount of root has often already been lost.
Internal Root Resorption
Internal root resorption is the loss of dentin from inside the root canal, caused by odontoclast cells activated within an inflamed but still partly vital pulp. Unlike external resorption (which works inward from the outside), internal resorption widens the canal from inside out — producing a characteristic ballooned or oval-shaped enlargement of the canal on imaging. It is much less common than external resorption but is more often saved when caught before perforation.
Horizontal Root Fracture
A horizontal (transverse) root fracture is a clean break that runs across the root of a tooth rather than down its length. It is almost always caused by a sudden blow — a fall, a sports impact, or a vehicle accident — and most often affects the upper front teeth in patients under 30. Unlike a vertical root fracture (which usually means the tooth must be extracted), a horizontal fracture can frequently be saved if it is diagnosed and stabilized within the first few days.
When to see an endodontist
Endodontists specialize in saving teeth. If you are experiencing any of the following, a specialist consultation is the next step — Dr. Kung accepts both dentist referrals and direct patient self-referrals.
Lingering pain to cold or heat
Cold or hot sensitivity that lingers more than 30 seconds after the stimulus is removed is the diagnostic hallmark of irreversible pulpitis — the pulp cannot recover and root canal therapy is required.
Sharp pain when biting or releasing
Brief sharp pain on biting (especially on a back molar) is the classic sign of a cracked tooth. The earlier a crack is diagnosed, the better the chance of saving the tooth.
Spontaneous, throbbing tooth pain
Pain that arrives without a trigger, throbs, or wakes you up at night usually means the pulp is irreversibly inflamed. Antibiotics will not relieve this kind of pain.
Visible swelling, pimple on the gum, or fever
A bump on the gum that comes and goes (a sinus tract), facial swelling, or fever points to a dental abscess — this is an emergency and needs to be drained, not just medicated.
A previously root-canaled tooth that hurts again
A root canal that fails years later may need retreatment or apicoectomy. CBCT 3D imaging is used to find missed canals, cracks, or persistent infection that a 2D X-ray cannot show.
A discolored tooth after trauma
A tooth that has turned gray, dark yellow, or brown after an injury — even years later — has likely lost its blood supply. The tooth can usually still be saved if treated promptly.
Treatments we provide for these conditions
Each condition above links to the treatments below. All procedures are performed by Dr. Jason Kung, specialist endodontist, under the Zeiss OPMI surgical operating microscope.
Frequently asked questions
What does an endodontist do that a general dentist does not?
Endodontists are specialists with two to three additional years of training focused exclusively on diagnosing tooth pain and saving teeth through procedures like root canal therapy, retreatment, and microsurgery. The work is performed under a high-magnification surgical operating microscope, with CBCT 3D imaging for diagnosis. Most general dentists refer their most complex root canals — molars, retreatments, and surgeries — to an endodontist.
When should I see an endodontist instead of a general dentist?
See an endodontist when you have severe or lingering tooth pain, swelling, a previously root-canaled tooth that is symptomatic again, a cracked tooth, dental trauma, or any case where saving the natural tooth is the goal. Your dentist may refer you, or you can self-refer.
Do I need a referral from my dentist?
No. Patients can book directly with Silicon Valley Endodontics by calling (669) 234-2354. We do work closely with referring dentists and will share all diagnostic findings with your general dentist if you wish.
How is a tooth infection diagnosed?
Diagnosis combines a clinical exam (cold testing, percussion testing, bite-stick test, palpation), 2D periapical X-rays, and three-dimensional CBCT imaging when needed. The diagnosis is built from the pattern of findings — no single test is definitive.
Can a tooth infection heal on its own?
No. Once the dental pulp becomes irreversibly inflamed or necrotic, the body cannot resolve the problem because the pulp is enclosed in a rigid chamber that cannot drain. Definitive treatment is either root canal therapy (saves the tooth) or extraction. Antibiotics are an adjunct for systemic spread, not a substitute.
Endodontic care — serving 30+ Bay Area cities
Dr. Jason Kung provides endodontic care to patients across Silicon Valley from our Sunnyvale office. Evening and weekend hours, same-day emergencies, free on-site parking.