Getting a root canal is often seen as an undesirable dental procedure. Many patients wonder if they can avoid a root canal altogether and simply get a filling instead. While in some cases a filling may be sufficient, most of the time a root canal is the only way to save a badly damaged or infected tooth. Understanding when a root canal is necessary versus when a filling will suffice comes down to the severity and location of the tooth decay.
What causes the need for a root canal?
Root canals become necessary when the pulp deep inside the tooth becomes irritated, inflamed, or infected. The pulp contains the tooth’s nerve, connective tissue, and blood vessels. When it becomes damaged, it is no longer viable and needs to be removed. Damage to the pulp that requires a root canal can occur due to:
- Deep decay from cavities
- Cracks or chips in the tooth
- Repeated dental procedures such as fillings or crowns
- Trauma such as a hit or blow to the tooth
In many of these situations, the decay or injury allows bacteria to penetrate deep within the tooth. This causes an infection in the root canal system. The infection cannot be removed with a simple filling, so a root canal is required to clean out the infected pulp and seal the tooth.
When can a filling work instead?
If the decay or damage to a tooth is minor and has not reached down to the pulp, a filling may be done instead of a root canal. Fillings can effectively treat small to mid-sized cavities that are located on the outer surfaces of the tooth. However, there are some caveats to this:
- Only fillings placed directly over the pulp have a chance of avoiding a future root canal. In these cases, the filling needs to be done shallowly and carefully to avoid penetrating into the pulp.
- If there are symptoms of pulpal damage such as pain when biting down or temperature sensitivity, a root canal is usually already needed.
- Front teeth have pulp chambers very close to the surface. Fillings on front teeth are unlikely to avoid the eventual need for a root canal.
Ultimately, fillings are only a temporary fix in many cases. About 10-15% of fillings on back teeth will eventually need a root canal procedure down the road.
Diagnosing the need for a root canal
To determine if a tooth requires a root canal versus being treatable with just a filling, the dentist will perform a few key diagnostic tests:
The dentist will look closely at the tooth, checking for cracks, signs of infection like bumps or swelling, or abscesses on the gums. They will test the integrity of the remaining tooth structure and look for evidence of damage spreading inward toward the pulp.
Dental x-rays allow the dentist to see beyond the visible surface, evaluating how deep any decay extends into the tooth layers. X-rays also reveal the condition of the root and bone around the tooth. Signs the pulp is affected include loss of structure, widening of the ligament surrounding the root, and presence of abscesses at the root tips.
A cold sensitivity test is done by applying cold air or ice to the tooth’s surface for several seconds. If there is inflammation or damage within the pulp, it will cause sharp pain that lingers for some time after the cold is removed. Prolonged sensitivity indicates a root canal is needed.
Tapping lightly on the tooth with dental instruments applies pressure to the tooth and surrounding tissues. If there is inflammation or infection around the root, percussion testing causes pain. This pain upon tapping signals a root canal is required.
Biting pressure test
Biting firmly on a dental stick applies pressure specifically to the tooth in question. If damage has spread to the pulp, biting down will cause severe pain. This is a tell-tale sign a root canal is necessary.
Pulp vitality testing
This electronic test sends a painless current through the tooth to stimulate the nerve. Normal healthy pulps will react to this stimulation. If there is no response, it indicates the nerve tissue is no longer vital and a root canal is needed.
Root canal treatment
If testing reveals the tooth’s pulp is diseased or necrotic, root canal therapy will be recommended. Here is an overview of how this procedure is performed:
Numbing and isolation
The area around the tooth is numbed with local anesthetic. A rubber dam is placed to isolate the tooth.
Accessing the pulp
A small access hole is drilled through the top of the tooth to expose the pulp chamber inside.
Special root canal tools are used to remove all the soft pulp tissue from inside the tooth. The root canal system is cleaned and shaped.
The entire root canal is disinfected using irrigation solutions like sodium hypochlorite. This kills any lingering bacteria inside the tooth.
Filling and sealing
The cleaned and disinfected root canal is filled with an inert rubbery material called gutta percha. It gets compacted into the canal space. The access hole is sealed.
A filling or crown is placed over the access hole to restore the visible part of the tooth. Together, the root canal filling and restoration seal the tooth from reinfection.
There may be mild soreness for a few days after treatment. Over-the-counter pain medication can help relieve any discomfort.
Advantages of root canal treatment
While avoiding root canal treatment is a common goal, there are many advantages to having a root canal over tooth extraction:
- Root canals allow retention of the natural tooth structure. This helps maintain the bite and smile.
- Having a restored tooth in place prevents the need for bridges or implants in the area.
- Restored root canal teeth can function normally, allowing proper chewing and biting force.
- Avoiding extraction helps preserve the jawbone at that site.
- Root canal therapy has a very high success rate, with treated teeth lasting many years.
For long-term tooth retention and function, root canal treatment is usually the best option compared to extraction. When diagnosed and treated promptly, root canals allow severely compromised teeth to be saved and restored.
When is extraction recommended over root canal treatment?
While most diseased teeth can be successfully treated with root canal therapy, in some cases extraction ends up being the better option. Reasons a root canal might not be advised include:
- The tooth cannot be restored due to extreme loss of structure
- There is inadequate bone support around the roots
- Serious cracks run vertically into the roots
- The tooth has a poor long-term prognosis even with root canal therapy
- A prior root canal has failed and the tooth has become reinfected
- The patient cannot afford the cost of root canal treatment
With proper diagnosis, most issues that make a tooth non-restorable can be identified early. This allows time for tooth extraction and planning implant replacement if needed.
Root canal vs filling cost comparison
|Procedure||Average cost range|
|Filling||$100-$300 per filling|
|Front tooth root canal||$300-$1500 per canal|
|Back tooth root canal||$500-$2000 per canal|
While a filling is significantly less expensive up front, remember that a filling has a shorter lifespan and a higher likelihood of needing a future root canal. In the long run, paying more for a root canal initially is often the more cost-effective approach. Dental insurance can offset some of the cost of root canal therapy as well.
Filling instead of root canal: Final considerations
It’s understandable why patients want to avoid extensive dental work like root canals. The idea of retaining the natural tooth structure is always preferable. However, when pulp disease is already present, a filling alone cannot reliably prevent the eventual need for root canal treatment.
In fact, delaying needed root canal therapy raises the risk of additional dental complications:
- Infection spreading to other teeth
- Cysts and abscesses around root tips
- Bone loss around the affected tooth
- Difficulties with anesthesia and complex root canal access
Catching the need for root canal treatment early while the tooth is still restorable yields the best long-term outcome. Though dental fillings have their place in preserving teeth, they cannot substitute for root canal therapy when pulpal disease has set in. Working closely with your dentist for an accurate diagnosis allows the right treatment plan to be put in place at the optimal time.
While fillings are a suitable treatment for mild decay, extensive damage involving the tooth’s pulp requires root canal therapy. Only root canal treatment can fully remove infection from inside the tooth and allow for placement of an adequate filling and restoration. With precise diagnosis and pulp vitality testing, dentists can determine whether a questionable tooth can be treated with just a filling or if a root canal is definitively needed. Catching and treating pulp disease in its early stages always leads to better prognoses. Partnering with your dentist for regular dental exams and prompt treatment helps identify teeth at risk for root canals before it’s too late.