How to avoid your worst endodontic disaster

by Kenneth Koch, DMD
and Dennis Brave, DDS

photo FPG Int'l.

We have all experienced endodontic volatility during our careers. Endodontic volatility is when a potentially profitable procedure deteriorates into a disaster. Conversely, it is also when a root canal is resurrected from a disaster into a predictable, less stressful, profitable procedure - a winner.

All dentists want to perform endodontics predictably, stress free, and profitably. When an endodontic procedure begins to degenerate, potential disaster looms. Here's how to avoid it.

The key to avoiding "endodontic disaster" involves multiple factors: proper case selection, accurate diagnosis, profound anesthesia, straight-line access, and avoiding iatrogenic incidents. In our first article we will examine the first two factors, and address the others in an upcoming article.

The first way to avoid a "disaster" is through proper case selection. You must be honest with yourself and decide whether or not you can properly treat the case. It is smart dentistry to decide that a case is beyond your experience and refer that patient to a specialist. This is not just about complex dental anatomy but also history and patient management. If the patient is merely anxious, make certain that you fully explain things before beginning the procedure. Informing patients about what you jointly are trying to accomplish will increase their tolerance of the procedure.

Also, let patients know that they do have some control over the situation. For instance, if something is painful, and they raise their hand, you will stop. Many anxious patients will actually test you on this accord. Work with the patient, not against them, and you will find your treatment progressing more smoothly.

The American Association of Endodontists has addressed the problem of case selection through the publication of a difficulty assessment form. Through a numbering system, based on difficulty, dentists are given a "heads-up" about the difficulty of the case they are about to treat. At first, such a system almost seemed tantamount to a "1-800-ENDO" concept. However, it rapidlly became apparent the system can be a great aid in identifying very difficult cases. We recommend that every dentist who performs root canals get a copy and understand its contents. You can obtain this document by contacting the AAE at (800) 872-3636, or by visiting their Web site, www.aae.org.

The AAE has performed a real service for the general practitioner. If filled out properly, the assessment form offers a defense to the endodontic legal nightmare. Should you find yourself giving testimony about why you felt capable of doing a particular case, you can rely on the case selection difficulty form to support your position. Your reply, if questioned, would be "I used the AAE Risk Assessment Form to evaluate the case before I started. The case presented none of the risk factors, so I felt perfectly comfortable treating Mrs. Jones." Talk about averting a potential disaster!

Once you have made the decision to treat a case, the next key is to confirm the diagnosis. Making the correct diagnosis and treating the condition appropriately is vitally important. To ensure accuracy, do not hesitate to take a second, angled X-ray. Also factor in the patient management issues, such as whether or not the patient is "difficult."

Diagnosis is universally regarded as the most difficult part of endodontic treatment. To make the routine less stressful, you must become comfortable with a predictable method of diagnosis. The following is a list of e some helpful diagonostic recommendations.

Real world diagnosis tips

Through the use of key questions, we can obtain vital information from patients:

• How long has this tooth been hurting? (Helps to differentiate between acute and chronic.)
• Does this pain wake you up at night? (Endo pain does; perio pain usually does not.)
• Do hot or cold liquids make the tooth hurt? (Cold positive usually indicates some type of pulpitis while heat sensitivity can indicate a degenerating pulp.)
• Is the pain spontaneous? (Endo pain is mostly spontaneous )
• Does the tooth hurt when you bite down? (Indicates inflammation in the PDL;also indicates a necrotic tooth or an occlusal discrepancy)
• Have you had any swelling? (Can indicate a possible necrotic tooth.)

Tip # 2: Take a second X-ray at a different angle

Following the initial discussion, we take an X-ray or X-rays of the suspected tooth. Taking two X-rays of the same tooth, with one X-ray angled (in excess of 15 degrees), assists with an accurate diagnosis. The angled X-ray will often show unusual anatomy that may be missed in the standard radiograph. Also, remember the "SLOB" rule: Same, lingual/opposite, buccal. If you move the cone head either mesial or distal, that part of the tooth (or canal) that goes in the same direction is to the lingual. If it moves opposite to the cone head, that object is buccally placed.

The second angled X-ray is one of the keys to avoiding an endodontic "disaster." Always look for ligaments when evaluating X-rays. This is critical to remember. By tracing these ligament spaces, you can diagnose multiple roots, figure eight canals, bifurcated roots, or teeth with strange anatomy. A perfect example of this is the mandibular premolar. Endodontists agree this tooth - usually a necrotic lower bicuspid - causes the most angst for the general practitioner.

Here is a typical scenario: The patient comes to your office and presents with a necrotic lower first bicuspid. Initially, the case appears simple. It is only one canal; since it is non-vital, anesthesia should not be a problem. You start to treat the tooth and your file goes down very nicely into the canal. Suddenly, after about 17 mm, the file stops! You know from the pre-op X-ray that the length is about 21 mm but you have now bottomed out at the 17 mm mark. You begin to realize that something is not quite right. The tooth is probably bifurcated. If this necrotic tooth flares up a little you might even get some swelling. If the swelling presses against the buccal nerve, this can lead to a potential nightmare, parasthesia. Once patients become parasthetic, they get upset.

The whole key to avoiding this disaster is proper diagnosis and knowing the true anatomy of the tooth. Unfortunately, the majority of endodontic anatomy textbooks in this country are out of date. This is because the original studies, though beautifully done, were on cadavers from Germany during World War I. This group was, dental morphology wise, quite generic. Lower molars had three canals, while lower bicuspids had one canal, and lower anterior teeth had single canals. Patients nowdays are more diverse. In North America alone we are seeing many more Asian patients and people from the Middle East. Asian patients often present with 4 canal lower molars, bifurcated or double-canal lower bicuspids, and quite frequently C-shaped mandibular second molars. If you treat a large Indian and Pakistani population, you will also encounter many double canal lower anteriors. Remember Tip # 2. The key to preventing a disaster in such cases is a good angled X-ray and reading the ligaments.

After the radiography is completed, we begin our clinical evaluation. Certainly, your office should have the proper equipment to conduct a basic endodontic evaluation. The basic endodontic setup consists of a mouth mirror, college pliers, combination periodontal probe and explorer, cotton roll, "tooth slooth," and "Endo Ice." This simple setup can accommodate more than 98 percent of your diagnostic demands.

Tip # 3: Perform a percussion test

The first clinical test to perform is the percussion test, one of the two most important endodontic tests. Begin percussion testing on an adjacent tooth or any tooth not felt to be involved in the problem. Always begin with light tapping, which you can increase as needed. By beginning on an uninvolved tooth, you avoid inflicting pain on the patient, who in turn retains confidence in the outcome you recommend. Tap on the affected tooth with a mirror handle and also tap on multiple adjacent teeth, ensuring a thorough examination.

A percussion-sensitive tooth indicates inflammation in the periodontal ligament. This pain can be the result of either a vital or nonvital tooth. Certainly, the inflammation from a hyperemic tooth can go to the PDL, which can result in percussion sensitivity. Also, hyperocclusion in a perfectly normal tooth can transfer inflammation to the PDL.

On the other hand, a necrotic tooth with bacteria and its by-products will often present with periapical involvement. This also will produce pain to percussion. To obtain a proper diagnosis, combine the information from the percussion test with that of a thermal test.

Tip # 4 Perform thermal testing

Once we have determined that a particular tooth is indeed sensitive to percussion, the next step is to determine the pulpal status of that tooth (vital or non-vital). Without question, the method most commonly employed by endodontists is the thermal test and, in particular, the cold test. Endodontists have used everything from ice sticks to CO2 to computer refrigerant. When performing a cold test, we strongly recommend using "Endo Ice." "Endo Ice" is a refrigerant made by the Hygenic company. It comes with a long nozzle in a green and white box. Take the "Endo Ice" and the nozzle out of the box, insert the nozzle into the can, and cut the nozzle back so that only a short piece remains. We recommend this to prevent the nozzle from flying off the can. "Endo Ice" gets very cold and you simply spray it on a cotton ball, give it a second to crystallize, and then place it on a dry tooth. Endo Ice is so cold it will actually penetrate a casting. If there is no response from the cold test, you must assume that the tooth is necrotic (nonvital). You can, however, test adjacent teeth to get a general sense of the patient's response to cold. If other teeth respond to cold, but the specific tooth does not, assume that the tooth is nonvital. However, if the patient does respond to the cold test, you must quantify the response. The key to this evaluation is time. How long does the tooth continue to ache from the cold? Does it throb? If you place a cold pellet on the tooth and the patient goes "ouch," what does this mean? A normal tooth will only take a few seconds for the cold to disappear but an inflamed tooth, with an irreversible pulpitis, will react with discomfort and throbbing that can continue for three to five minutes.

Therefore, the key to evaluating your patient's response to cold is throbbing and its duration. Patients with an irreversible pulpitis generally will make a face, close their eyes, and start to roll their tongues. The tongue is warm and the heat is comfortable.

Heat tests generally are not necessary. However, if you choose to perform one, the best way is to isolate the tooth with a rubber dam and clamp (no anesthesia), and flood the tooth with a hot liquid, such as coffee or tea. These liquids hold the heat better than straight hot water. Make certain you have high-speed suction ready to evacuate the liquid when the tooth starts to respond. This test is much kinder to the patient than placing hot gutta percha on the tooth. In fact, we recommend you avoid placing hot gutta percha on a tooth.

Heated gutta percha can be difficult to remove from the tooth, resulting in prolonged agony for the patient. Hot gutta percha is even more difficult to remove from a moving target! Remember, heat tests are rarely used by endodontists.

Tip # 5: Know the limitations of EPT testing

The EPT(electric pulp tester) is probably the most common - and least accurate - piece of equipment the general practitioner uses for diagnosis. Endodontists rarely use EPTs. This tool can be used as an adjunct during diagnosis, but its scope is limited. There are too many false readings associated with the EPT. A false reading can exacerbate an already anxious patient to near hysteria. The only time it means anything to most endodontists is if it generates no response. Then, we can assume that the tooth is either anesthetized or necrotic. However, the percussion and thermal tests, when combined, are far more accurate in determining a diagnosis.

These tips should assist you in making the correct diagnosis and avoiding the nightmare of your patient saying, "Doctor, I think you treated the wrong tooth!" Talk about a disaster! This is one of the worst! Watch your fee go right out of the window. Also, how do you justify a fee now to treat the correct tooth? We have yet to mention the confidence lost by the patient and all their friends who could have been future patients.

Our next article will solve your worst disasters regarding cracked teeth and inadequate anesthesia. With proper information, endodontics can be profitable and pain-free - for you and your patients.