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Root Canal Wonderland

by | May 4, 2016 | BLOG |

Root Canal Wonderland

by Stephen H Hook, DDS   Westchester Los Angeles Dentist


“My heel? Are you kidding? I’m going to die from a root canal!” Achilles

No matter what your mind conjures up when you hear the term “root canal” there’s much more to the story.  Do you think of the discomfort, infection and embarrassment often used by stand-up comedians to get a laugh?  How about a scene from a gory horror film?  Perhaps as the title suggests, you have an indistinct idea of a root canal somewhat akin to a rabbit disappearing down a rabbit hole and reappearing as the Queen of Hearts!  No matter where you are when you start reading I promise you that you will come out the other end more knowledgeable and perhaps even as philosophical as our chain smoking purple caterpillar of wonderland legend.

What is a “root canal”?

“Root canal” strictly speaking is not a procedure or treatment but rather a space in the center of natural teeth where soft tissue called “the pulp” resides.  When the pulp is healthy it is quiet and only slightly sensitive to normal stimuli like hot and cold.  When the pulp is irritated, say like your skin when sunburned, then it gets quite sensitive and reacts violently to most stimuli–in short a toothache begins.  Sometimes (infrequently) the pulp can return to normal and become healthy again, but more often than not the pulp, once irritated enough to ache, will eventually degenerate and die.  Once the pulp is totally dead it may stop aching, but it is full of dead, putrefying debris–gangrene has set in.  When this happens, just like the old civil-war stories, you can hack off the leg (extract the tooth) OR if you wish to preserve the tooth, a better alternative is usually available – you can have “endodontic therapy” (root canal treatment ) and save the tooth.

When and Why We Do a Root Canal

The objective of root canal therapy is to save a tooth that would otherwise need to be extracted and return it to useful function in the mouth.  This point needs to be made at the outset: not all teeth are restorable and valuable enough for root canal therapy.  I will discuss primarily how root canal therapy is accomplished, but never forget that root canal therapy is much more than stopping a toothache; it must be the first step in total rehabilitation of the tooth or else the “root canal filling” will be an expensive failure.

How We Do a Root Canal

If a tooth is filled with infectious, dead tissue it must be successfully disinfected and filled, in order that the toxins inside the tooth are eliminated and the surrounding tooth socket in the bone and gum be allowed to heal.  This meticulous cleansing, shaping, enlarging, and filling of the root canal itself is time consuming and challenging for the dentist but most times it is almost entirely pain-free.  Since the pulp is dead the tooth has no feeling inside and if the preparation of the root canal is done excellently there is little or no sensation felt by the patient.  Most all root canal treatment is done under local anesthesia (novocaine) and patients report feeling virtually no discomfort at all.  The pain associated with root canals typically comes before the patient sees the dentist and is usually the result of neglect.  The discomforts patients report during and after typically are tenderness from the shot and soreness from having to hold their mouths open for a long period of time. Post-operatively prescribed antibiotics and analgesics (pain relievers) when needed keep the patient quite comfortable between appointments.

Root Canals Are Not a Source of Infection

Properly completed root canal fillings have a very high rate of success (>97%).  Close to a century ago the treatment philosophy was cruder; some believed that mumification of the root canal debris with agents such as formaldehyde was adequate.   This theory was thoroughly disproven and no longer given credence.  Now we thoroughly disinfect the root canal and we place a sterile inert filling that is well tolerated by the body.  My only reason for mentioning this point is the persistence of the myth that root canal filled teeth are a source of poison and infection endangering the entire body.  A successful root canal filled tooth is accepted by the body equally well as the normal tooth that has not had endodontic treatment.  It is a myth that a tooth with a root canal filling causes infection and stresses the body’s immune system.

As explained earlier, root canal treatment is needed when the pulp dies.  The main cause of pulp death is tooth decay but there are other factors that create a need for root canal treatment besides decay. Trauma can kill the pulp of a tooth either by breaking away so much tooth structure that the pulp is exposed, say in the case of an accident or by the pounding and attrition over time from destructive habits such as clenching and grinding. The pulp can also get infected through the root by an advanced gum infection which has progressed deep into the pocket space around the tooth.

Once the need for the endodontic treatment as been verified then the first part of the treatment is to measure, clean out, shape and disinfect the canal space(s) in preparation for the filling procedure.  This first part can take quite awhile in the case of a multi-rooted molar tooth.  The canals can be many, twisted and tightly curved as well as blocked off by stones.  All of these challenges need to be successfully completed before the canal(s) can be filled. The filling step can also be tedious and fraught with difficulties if the dentist is faced with several bent and twisted canals to fill.  Placing filling material needs to be precise.  We want the filling to be sterile, dense, inert and totally fill the root canal space leaving no void but not extending beyond the root into the bone and gum supporting the tooth.

Once the filling step of the root canal is complete we turn to the all-important step of restoring the tooth to full function.  Too often this step is forgotten.  The patient may want a psychological break from the dental chair or the additional cost of the restoration may give them pause since the whole root canal experience tends to be a surprise in the first place.  For whatever reason, it is important that the final restoration of the root canal filled tooth not be delayed.  The tooth as we write of it now is usually a shell–a very fragile shell at that–it cannot withstand normal chewing function without a crown to strengthen it.

In nearly all cases a tooth with a new root canal filling will need a crown to restore it to function.  The main exception might be a tooth that already had a crown on it to begin with and the root canal procedure was able to be completed without removing the existing crown.  A crown binds the fragile edges of the tooth together and lends it strength so that the tooth can bear up under chewing stress.  Many times the tooth root will need reinforcement with a post made of fiberglass, ceramic or metal to tie the root that is anchored in the bone to the crown. The crown must have a firm grip on the root to become an intact unit.  This post if needed, is bonded or cemented into the middle portion of the root canal space.  Part of the filling is removed to allow bonding of the post.

How Long Does a Root Canal Take?

The total number of visits needed to complete a root canal filling and to restore the tooth varies widely depending on the complexity of the tooth roots and the difficulty of restoring the tooth once filled.  Also, a dental specialist (Endodontist) maybe called upon to treat the most difficult and complex root canals.   In my office I have completed root canal fillings in one visit and restored them with crowns in two visits.  It is not unusual for patients with uncomplicated cases to have the entire process completed in three visits averaging 75–90 minutes each.  Difficult cases with complex restorations have taken twice as long.  Costs increase with complexity and Endodontists’ fees are significantly higher than mine, as a general dentist.

How Long Does a Root Canal Last?

Once completed, the successful root canal filled tooth can be retained for the rest of your life BUT it is subject to new decay, gum disease with bone loss and replacement of the crown when it wears out.  In short, the tooth is vulnerable to all the same threats as it always was; the root canal filling offers no “Alice in Wonderland” miracles. Still, the objective at the start was to save the tooth rather than have the “Civil War” amputation.  Salvaging the tooth is a wise decision but as you can see it can be a bit stressful and expensive once you follow the rabbit down the rabbit hole.  Better to be diligent with your brush, floss and dental checkups and leave the fanciful excursions on the pages of Lewis Carroll’s imaginative prose.