What an Endodontist Does and When You Need One
Revised September 6, 2026
Why would a dentist send you to an endodontist?
Because the inside of your tooth needs more than a routine filling. A curved or calcified canal, a molar with extra canals, a previous root canal that failed, or pain nobody can pin down all call for a specialist with a surgical microscope. A referral is good judgment, not bad news.
Keep reading ↓The front desk in Des Peres handed Marisol a slip of paper with a name, a phone number and one word she had to read twice. Endodontist. Her dentist had explained it in about ninety seconds, somewhere between a curved root, a molar with an extra canal and a microscope he did not have in the building. She nodded the way people nod when their jaw is throbbing and they want to be anywhere else. Then she sat in her car in the lot, held a cold bottle against her cheek, and typed the word into her phone with one thumb.
The same week, other people around the metro are circling the same question from different directions. A man in Ellisville has a lower molar that only hurts when something cold hits it, and only for a second, so he keeps putting it off. A woman in Imperial had a root canal done years ago, forgot about it entirely, and now that tooth has started to ache when she bites down. A dad in St. Charles is holding a paper towel and a chipped front tooth after his daughter took a ball to the mouth at practice. And a retired teacher in Manchester has a crown that has begun to feel wrong, not painful exactly, just wrong, and she cannot explain it any better than that to anybody.
They all want the same four things. What is this specialist, and why me. What is going to happen while I am in that chair. Is it going to hurt. And what is this going to cost me, all in, including whatever comes after. Here is what an endodontist is trained to do, why general dentists refer teeth out, what the appointment is actually like start to finish, an honest answer about pain, why the crown afterward is a separate bill from a separate person, what to watch for once you are home, and the symptoms that mean you stop reading and get seen today.
Why would a dentist send you to an endodontist?
Because the inside of that particular tooth turned out to be more complicated than a routine filling can handle. Your dentist looked at an x-ray, or at the tooth itself, and decided the work needed tools and time that a specialist is set up for. That decision is a good sign about your dentist, not a bad sign about you.
The usual reasons are ordinary and mechanical. Roots that curve sharply. A molar with more canals than the textbook average, tucked where a standard x-ray flattens them into one shadow. A canal that has calcified and narrowed with age until it is hard to find at all. A root canal done years ago that now needs to be redone. Pain that has not settled after treatment. Or simply a tooth that your dentist judges sits at the outer edge of what he or she should attempt in one afternoon.
Plenty of general dentists do root canals well, especially on front teeth with a single straightforward canal. The referral happens when the odds shift. And it is worth saying clearly, because almost everybody sitting in that parking lot assumes the opposite: nothing has gone wrong. A referral is your dentist declining to guess.
What is an endodontist, and how is the training different?
An endodontist is a dentist who finished dental school and then completed two or more additional years of accredited specialty residency, focused entirely on the dental pulp and the tissues around the root. It is a recognized dental specialty. Most endodontists limit their practice to that work, which means they are doing all day what your general dentist does occasionally.
The equipment matters at least as much as the years, and it is the real reason a specialist visit feels different. A surgical operating microscope brings the floor of the tooth into view at a magnification no set of loupes reaches, which is how a hidden or calcified canal gets found instead of missed. Cone-beam CT produces a three-dimensional image of the root and the bone around it, so anatomy that a flat x-ray stacks on top of itself becomes separate and visible. You cannot treat a canal you never saw.
It also helps to keep one line straight, because these two specialists get confused constantly. The oral surgeon removes the tooth. The endodontist saves it. Both are legitimate answers to a badly infected molar, and sometimes a tooth genuinely cannot be kept, but they are opposite jobs. If extraction is on the table for you, what an oral surgeon does and what it costs covers the other side of that fork.
What else does an endodontist treat besides root canals?
More than most people expect. Retreatment is a large share of it, meaning a root canal done before that has failed or was never fully completed, where the old filling material has to come out before the canal can be cleaned properly and sealed again. When infection persists at the tip of the root even after good treatment, an apicoectomy removes that root tip surgically and seals the end.
Cracked and fractured teeth land here too, including the ones that ache only on release when you bite a seed or a piece of ice. So does dental trauma. A tooth knocked out or shoved out of position by an elbow, a ball or a fall is an endodontic problem, and time matters a great deal, which is why a mouth injury is worth a same-day call rather than a Monday appointment. Internal resorption, where the tooth begins breaking down from the inside, is on the list as well.
Then there is the category that brings in the most frustrated patients: the diagnostic case. Somebody knows something hurts, has been to two offices, and nobody can say which tooth it is. Sorting that out with cold testing, bite testing, percussion and three-dimensional imaging is squarely specialist work.
What actually happens at the appointment?
It starts with questions and testing, not drilling. Expect to be asked what triggers the pain, how long it lasts after the trigger goes away, and whether it wakes you up. Then cold on the tooth and its neighbors, tapping, a bite test, and imaging. Cold that lingers for a minute after the stimulus is gone tells a very different story than cold that vanishes instantly, and that difference often decides the plan.
If treatment goes ahead, you are numbed with local anesthetic and a small rubber sheet called a dam is placed to isolate the tooth and keep the field clean. A small opening is made through the top of the tooth. The inflamed or infected pulp is removed, the canals are cleaned, shaped and irrigated, and the whole thing is done under the microscope with the specialist checking measurements as they go. The canals are then filled with a sealing material and the opening is closed with a temporary filling.
Some teeth are finished in one visit, some in two, and that is a clinical call rather than a sign of trouble. Front teeth are generally quicker than molars for the plain reason that there is less to do. You will leave numb, with instructions, and with one more appointment to make: the permanent restoration, back at your general dentist.
How much does a root canal really hurt?
Here is the honest answer. The pain most people remember from a root canal is the infection beforehand, not the treatment. The procedure itself is done under local anesthetic, and the whole point of it is to remove the inflamed tissue that has been keeping you awake. That reputation the procedure carries was earned decades ago, before the anesthetics, instruments and magnification available now.
There is a real caveat, and you deserve it straight. A tooth that is actively inflamed or abscessed can be harder to get fully numb, because the surrounding tissue chemistry works against the anesthetic. That is why a dentist sometimes starts antibiotics first, or schedules the treatment a few days out, or uses supplemental techniques to get you comfortable before starting. If you have had a bad experience with numbing before, say so at the front desk when you book. It changes how they plan your visit.
Afterward, soreness for a few days is normal, especially when biting on that side, and it usually fades a little each day. What is not normal is severe pain, pain that is getting worse rather than better, or swelling. That is a call back to the office, same day, not something to sit on over a weekend.
Once the tooth is behind you, there is a golf season waiting.
Why is the crown a separate bill from a separate person?
Because two different providers are doing two different jobs. The endodontist treats the inside of the tooth and closes it with a temporary filling. A back tooth that has had a root canal has been hollowed out and usually needs a crown to keep it from splitting under chewing force, and that crown is normally placed by your general dentist, at a separate appointment, on a separate bill. This is the single biggest source of cost confusion in the whole topic.
It is also why people ask, reasonably, What’s more serious, a root canal or a crown? They are two halves of one repair. The root canal ends the infection; the crown protects what is left of the tooth so the repair holds. Skipping or delaying the crown on a molar is how a successfully treated tooth still ends up fracturing, and a fractured tooth often cannot be saved at all.
On cost, think structurally rather than chasing a number you read somewhere. A molar has more canals and takes longer than a front tooth. Retreatment of a previous root canal is harder and slower than a first treatment. Specialist fees are set differently from general dentistry fees. The crown afterward is its own charge from a different office. And dental insurance annual maximums mean that two procedures landing in the same plan year can play out very differently from the same two procedures split across a January. Ask both offices for a written estimate and ask your plan for a pre-treatment estimate before you start. If paying for it is the obstacle, free and low-cost dental care in St. Louis lists the options worth calling.
What should you watch for afterward, and when is it an emergency?
For the first few days, chew on the other side, take whatever your provider recommended for soreness, and protect the temporary filling. Then keep the appointment for the permanent restoration, and keep the follow-up x-ray your endodontist asks for. That follow-up image is how healing at the tip of the root gets confirmed, and it is the appointment people skip most often because the tooth already feels fine.
A well-treated and properly restored tooth can serve you for many years. Failures do happen, and they have identifiable causes: a canal that was never found, a new crack, decay working its way under the restoration, or a crown that was delayed long enough for the tooth to fracture. Most of those are catchable early on a routine x-ray, which is the practical argument for not disappearing from the dentist once the pain stops.
Now the part that is not wait-and-see. Severe swelling, swelling that spreads toward your eye or down into your neck, fever, or any difficulty swallowing or breathing means immediate care, not an appointment next week. Go to an emergency room or an urgent care, tonight. A dental infection that has left the tooth and moved into the surrounding spaces is a medical emergency, and it can move fast. Nothing in this article is a diagnosis, and no article can be. You need to be examined by someone who can see the tooth.
How do you choose an endodontist in the St. Louis metro?
Start with your dentist’s referral, then shortlist two or three practices and treat each call as an interview rather than a booking. You are allowed to ask questions before you commit to a procedure, even when your jaw hurts, and the answers you get tell you a great deal about how the office runs.
Ask four things plainly. Do you use a surgical operating microscope and cone-beam CT, and will they be used for my tooth? Who places the crown afterward, my general dentist or you, and how soon does it need to happen? What is the plan if the tooth turns out to be unsavable once you are inside it? And how do you handle a flare-up after hours or over a weekend? Then compare the answers against what each office is actually prepared to tell you. The gap is the signal.
While you are on the phone, settle the logistics that derail people later. Confirm whether they are in network with your plan, whether they will submit a pre-treatment estimate, how long the visit is scheduled for, and whether you will need someone to drive you. An office that answers all of it in one call without hedging is usually an office that runs the rest of its day the same way.
Do not sit on a tooth that is getting worse. You can browse endodontists across the metro on St Louis Near Me Directory, shortlist two or three near you, and ask each one about the microscope, the crown timing and after-hours coverage before you book. What comes back, and how quickly, tells you most of what you need to know.
For endodontists and dental practices in the metro
If you are on the other side of this, look again at who was in the opening paragraphs. None of them wanted a brochure. They wanted to know what the referral meant, what the visit involves, whether it would hurt, and what the total looks like once the crown is counted. The offices that answer those four questions in plain language on their own website earn the call before the phone ever rings.
Two practical things. Say clearly who places the restoration afterward and how soon, because that gap is where referred patients get lost and teeth get fractured. And publish how a patient reaches you after hours. A person with a swelling face at nine on a Friday night is making a decision in ninety seconds, and clarity is what wins it.
Frequently asked questions
Do endodontists do anything besides root canals?
Yes, quite a lot. They retreat root canals that have failed, perform apicoectomies to remove and seal an infected root tip surgically, manage cracked and fractured teeth, and handle teeth knocked out or displaced by trauma. They also treat internal resorption and take on diagnostic cases where a patient knows something hurts but nobody has been able to identify which tooth is responsible.
Are endodontists more expensive than dentists?
Specialist fees are set differently from general dentistry fees, and the visit typically involves more time, three-dimensional imaging and microscope work. Beyond that, the tooth drives the number: a molar has more canals and takes longer than a front tooth, and retreating a previous root canal is harder than doing a first one. Ask for a written estimate and a pre-treatment estimate from your insurance plan before you begin.
What happens 10 years after a root canal?
Usually nothing dramatic. A tooth that was treated well and restored properly with a crown often keeps working like any other tooth. When problems do surface later, the causes are identifiable: a canal that was never found, a new crack, decay reaching under the restoration, or a crown that was delayed until the tooth fractured. That is exactly why follow-up x-rays at routine checkups matter.
Why do dentists try to avoid root canals?
Because keeping the pulp alive is always the better outcome when it is still possible. A smaller intervention, a filling or a protective liner, preserves more tooth structure and costs you less time and money. A tooth that has had its pulp removed is also more brittle and usually needs a crown to survive chewing. Dentists are not avoiding root canals out of fear; they are saving them for when the pulp cannot be rescued.
What is the most painful stage of a root canal?
For most people it is the stage before treatment, when the pulp is inflamed or abscessed and nothing touches the ache. During the appointment, the hardest moment is often simply getting fully numb, since an actively infected tooth resists anesthetic. Once numb, patients frequently describe the rest as tedious rather than painful. Soreness for a few days afterward is normal; severe or worsening pain means call the office.
Can a tooth be rotting under a crown?
Yes. Decay can develop at the margin where the crown meets the tooth, or underneath it, and it is often completely painless until it reaches the pulp. That is why a crown that starts to feel odd, catches floss, or becomes sensitive deserves an exam rather than a wait. Dentists find most of these on routine x-rays, which is one more reason to keep checkups even when nothing hurts.
More St. Louis guides
- What an Oral Surgeon Does and What It Costs
- Free and Low-Cost Dental Care in St. Louis
- What a Pediatric Dentist Does and When to Start
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