RATIONALE FOR TREATMENT
EVIDENCE-BASED ENDODONTICS

Success is comprised of many elements, including making an accurate diagnosis. The first procedural step is complete access which provides the opening for finding all the orifices and canal systems. Next, we prepare a canal with efforts directed towards fulfilling the mechanical objectives of cleaning and shaping. Over time, it is becoming understood that files shape...irrigants clean. Importantly, shaping facilitates cleaning and shaping facilitates obturation. Vertical condensation carries a wave of warm gutta percha and sealer into all aspects of the root canal system resulting in three-dimensional obturation. Following endodontic treatment, dentists must produce restorations that are esthetic, well-designed and that achieve a coronal seal.

Sodium hypochlorite is a powerful, inexpensive and, when used correctly, safe irrigant that has been repeatedly shown to eliminate vital and necrotic tissue, and when present, bacteria and related byproducts. Think of the root canal system as a tree. A tree is comprised of a main trunk with smaller branches. Clinicians shape a root canal utilizing instruments with efforts directed towards preparing the main canal. Shaping removes restrictive dentin. A shaped canal holds an effective reservoir of irrigant which can penetrate, circulate and clean into the lateral branches. A series of files progressively opens and shapes the main canal, but it is the irrigant that potentially cleans a root canal system.

Root canals fail due to microleakage and bacterial infection. The precise cause of endodontic failures can be attributable to inadequacies in three-dimensional cleaning, shaping and obturation. Additionally, failures occur because of missed canals, iatrogenic events, radicular fractures, or re-infection of the root canal system when the coronal seal is lost after the completion of root canal treatment. Regardless of the etiology, the sum of all causes is leakage, bacterial contamination or re-contamination.

If we have an accurate endodontic diagnosis, if subsequent treatment is properly performed, and if the tooth receives a well designed restoration that achieves a coronal seal, then success rates can potentially approach 100%. In fact, the only teeth that cannot be endodontically saved are teeth with radicular fractures, with hopeless periodontal disease or that are nonrestorable. Regrettably, most success and failure studies have been conducted over short timelines such as six months, one or two years. Unfortunately, there have been few studies that have been conducted over timeline horizons of say 10, 15 or 20 years.

The good news is there is enormous potential for success. Better trained dentists, in conjunction with a general public who increasingly votes for endodontics as an alternative to the extraction, have synergistically led to the annual treatment of over 50 million cases in the United States alone. The bad news is even if we assume that 90% of all endodontics works, the reciprocal failure rate is 10%. Ten percent of 50 million equates to the possibility of 5 million failures per year. It should be understood that it may take 3, 4 or 5 years for an endodontically treated case to fail. Time catches up with deficiencies in endodontic treatment.

There is no dental literature that I am aware of that can quantify a percentage. However, the dental pulp is vulnerable because it has a poor blood supply, is encased in unyielding dentinal walls and is terminal circulation. It is important to recall that dentin is tubular and bacteria can easily pass through these tubules into the pulp proper. It is also important to note that a crown is rarely the first restorative a tooth receives; rather it is typically fabricated after multiple episodes of caries, leakage and restorative procedures. As such, many crowned teeth do, in fact, eventuate in endodontic treatment.

The Ruddle Solution, although not yet available commercially, is a composition of NaOCl, hypaque and EDTA. To get the "correct" concentrations of each reagent requires professional formulation by a chemist. However, in the U.S. it is possible to get hypaque from a pharmacy. More information on the Ruddle Solution is also posted to the Inventions page of this site.

The term “pulpal therapy” describes the various procedures which are intended to maintain the health of the pulp. An example of pulpal therapy is performing a pulp capping procedure on a vital pulp exposure when the patient is asymptomatic. The term “therapeutic pulpotomy” describes a procedure directed towards removing all of the tissue inside the pulp chamber. A therapeutic pulpotomy is employed to maintain the health of the radicular tissue or to use this tissue to induce root maturation. The term “pulp therapy” or “root canal therapy” are terms frequently misused to describe those endodontic procedures that are intended to be definitive. In summary, the word “therapy” designates those procedures directed towards preserving the remaining pulp, whereas “treatment” defines those procedures directed towards removing the pulp, and if present, bacteria and related irritants. The word “treatment” also includes all procedures utilized in conventional, nonsurgical or surgical endodontics.