If you're facing an unexpected return to the dentist's office due to a root canal failure, then chances are you're wondering what could have caused this tooth-saving treatment to fail. There are several reasons why an initially successful root canal can suddenly turn bad. The following explores exactly how this can happen, and you'll also learn about the steps your dentist may take to undo the damage.

Undetected Canals

It's not uncommon for an incisor or a molar to have an extra canal branch hidden near another canal. In most cases, the hidden canals are located deep enough within the tooth that most root canal instruments can't reach it. In other cases, the canal branches off near a curve in the main branch, making difficult if not impossible for instruments to reach it.

If they're not found by your dentist, a hidden canal can become a last-ditch refuge for bacteria, resulting in an infection that can cause abscesses and other dental complications. For this reason, hidden canals are a common cause of root canal failures, even after a seemingly successful treatment.

Your dentist may be able to re-do the procedure and tackle the hidden canal. If the damage caused by the hidden canal is severe enough to warrant a complete removal of the tooth, your dentist may recommend extracting the tooth altogether and replacing it with a bridge or dental implant.

Root Canal Instrument Problems

Endodontic files are commonly used to remove the pulp and nerves within the tooth canal. Unfortunately, it's not uncommon for the tip of the file to separate from the rest of the instrument, leaving a small part of the file within the canal. This could potentially cause the root canal to fail over time, especially if a poorly sterilized file acts as a vector for bacterial infection.

The Chicago Dental Society notes that your dentist must inform you if and when a root canal instrument is lost or broken within the root canal. In addition to documenting the incident in your dental records, your dentist should also conduct an X-ray to pinpoint the file's location within the root canal. If the procedure is being performed by a general dentist, he or she should refer you to an endodontist for further possible treatment.

In many cases, the file can be safely removed from the canal and the tooth properly restored to its original appearance. However, if the file separates deep within the canal, your dentist or endodontist may have no other choice than to leave the file in place and bypass it in order to continue treatment.

Broken Crowns, Fillings and Teeth

After removing the pulp and nerves from the tooth root, the now-empty space is filled and sealed off with a rubber-like material to prevent bacteria from recolonizing the root. Your dentist will also top the root canal with dental cement and place a crown over the tooth to keep bacteria out and give the tooth extra protection against fractures. In some cases, a silver or composite filling may be used in lieu of a crown.

However, the crown itself can loosen or fracture if it isn't bonded correctly or if the material used to create the crown can't withstand the bite forces it's subjected to. Fillings can also come loose or cause the surrounding tooth to fracture, allowing bacteria an opening to re-enter the tooth.

Crowns and fillings can be replaced, usually after the root canal procedure is re-done properly to remove any and all traces of bacterial infection. If the tooth itself is fractured or broken, however, your doctor may have no choice other than to extract the entire tooth.

Failure to Maintain Good Dental Hygiene

Even the best dental procedure can fail due to poor hygiene. Slacking off on your dental hygiene after having a root canal done can easily cause bacteria to re-enter the tooth, resulting in the need for another root canal or other, more drastic measures being taken later on.

Maintaining good dental habits is the key to helping your root canal last you for the rest of your life. For example, brushing twice daily and flossing at least once a day can help prevent plaque and other bacteria from accumulating around the base of the teeth and gum line, resulting in tooth decay and gum disease.

Yearly checkups with your dentist are also essential for maintaining good dental health. These regularly scheduled checkups can help prevent the need for further root canal treatments later on in life.