Seongmo Dental Clinic · Seongbuk-gu, Seoul
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When it works, and when it does not · Seongmo Dental Clinic, Sungshin Women’s University Station · Board-certified specialist in Integrated Dentistry
💡 The short answer. Yes. If the crack stays above the gum line and the cusps on the biting surface can be covered, an overlay can preserve the side walls instead of preparing the whole tooth for a crown.
The point is to cover the biting surface so the crack cannot open, and an overlay achieves that while removing less tooth.
Seongmo Dental Clinic removes the cracked area, checks the state of the pulp, and finishes the overlay the same day in about 1 hour 30 minutes.
Contents
A crack opens slightly at the moment of biting and closes again when the force is released.
At the moment it opens the stimulus reaches the nerve inside, producing a sharp twinge that disappears when it closes.
A radiograph only catches a crack while it is open, so most do not show. Diagnosis therefore relies on testing rather than images: biting on each cusp in turn to find which one hurts, transillumination to see the crack line, and CBCT where needed to check for a crack towards the root.
Left alone, a crack only goes one way. It deepens with every bite, and when it reaches the nerve a root canal becomes necessary; if it runs down to the root, the tooth must come out. That is why a cracked tooth should be covered at the point it is found.
To stop the force that opens the crack, the biting surface and the cusps must be covered with a hard material that binds them together.
A crown certainly achieves that, but the sides of the tooth have to be prepared all the way around as well.
In a tooth whose sides are perfectly sound, preparing them means losing tooth structure that has nothing to do with the crack.
An overlay covers the biting surface and the cusps while leaving the side walls. Because the ceramic bonds to the tooth and binds the cusps, its role in resisting the force that opens the crack is the same as a crown’s. The amount of tooth removed, however, drops considerably.
Three conditions make an overlay possible: the crack stays above the gum line; sound tooth structure remains below the cusps to be covered; and enamel remains at the margin for bonding.
Seongmo Dental Clinic considers an overlay first when these are met, and goes to a crown when they are not.
The difference between the two is set out on the digital same-day prosthetics page.
Not necessarily. Even if the nerve is exposed while removing the cracked area, a tooth with healthy bleeding and pain that did not linger can be saved with a pulpotomy, without removing the whole nerve.
Seongmo Dental Clinic opens the cracked tooth, checks the state of the nerve directly, and then decides.
The record of a cracked molar finished in 1 hour 30 minutes on the same day with a pulpotomy and an overlay is in our clinical cases.
It can. After painless anaesthesia the damaged area is removed along the crack, the state of the nerve is checked, and Plazen plasma disinfection is applied.
It is then scanned with Primescan, the ceramic block is milled on Primemill, fired in SpeedFire and bonded.
With no temporary-tooth stage, the tooth is covered that day without giving the crack room to open.
Costs are on the non-covered fee guide, and ceramic overlays carry a 3-year warranty on the basis of regular check-ups.
Where the crack has run below the gum line, or has split in several directions leaving thin walls, a crown is safer.
Where the root is split vertically, not even a crown can save it and extraction with an implant is considered.
A crack is a problem whose options narrow with time, so if you have a sharp twinge on biting, please do not put it off.
30 seconds on foot from Exit 2 of Sungshin Women’s University Station, +82-2-922-3966.
Why does a cracked tooth not show on a radiograph?
A crack opens only while biting and closes again, so it is mostly not captured on radiographs. Diagnosis is made by biting on each cusp in turn and by transillumination.
What happens if a cracked tooth is left alone?
The crack deepens with every bite; when it reaches the nerve a root canal becomes necessary, and if it runs to the root the tooth must be extracted. Covering it when it is found is what protects the tooth.
Is an overlay not weaker than a crown?
Because the biting surface and cusps are covered in bonded ceramic, its role in resisting the force that opens the crack is the same as a crown’s. For a tooth that meets the conditions there is no reason to choose a crown on strength alone.
How many visits does overlay treatment take?
With in-house scanning, milling and firing, bonding is completed the same day in about 1 hour 30 minutes, so one visit. If root canal treatment is needed, that stage is added.
Related information
Seongmo Dental Clinic opened in 1998. I have held this position as the third director since April 2022, and I have one standard for choosing equipment: if I would not use it on my own family, I do not use it on my patients.
One more scanner must not mean more treatment. If anything, it should mean cutting less, extracting less and finishing in one visit, from a more accurate original.
The goal is not to be first with new equipment, but to offer the better of what is possible today to the patient sitting in the chair.
📍 3rd floor, 2 Dongsomun-ro 20ga-gil, Seongbuk-gu, Seoul
🚉 30-second walk from Exit 2, Sungshin Women’s University Station (Parking: up to 2 hours at Utah Mall)
📞 +82-2-922-3966
📅 Mon/Wed/Fri 09:30–18:30 · Tue 09:30–20:00 (evening clinic) · Sat 09:30–14:30 (no lunch break) · Weekday lunch 13:00–14:30 · Closed Thu, Sun and public holidays
💬 Booking and enquiries: Naver Booking · Naver Talk · KakaoTalk channel · English page
🟡 Opened in 1998; third-generation director in charge of care since April 2022
⚕️ This article was written for information purposes in line with Korean medical law and the Ministry of Health and Welfare’s medical advertising standards.
Equipment specifications given here come from the manufacturer’s official material and the figures on accuracy and comfort are values reported in academic literature; the outcome and course of individual treatment vary with the condition of the mouth.
Please decide on a specific diagnosis and treatment plan after consulting your treating clinician.
This article was written as of August 2026. Equipment specifications and cost-related content are reviewed and updated every three months.
Peer-reviewed sources supporting the explanations above, selected by Dr. Tae-yoon Jang (Director, Seongmo Dental Clinic). Individual results may vary.
