June 1, 2007
by Richard Mounce, DDS
How often do we examine a patient experiencing pain and wonder if the problem is odontogenic or of another origin? Making matters more complicated, how often have we concluded that the patient’s problem is of dental origin but we are unable to localize the offending tooth? With a patient in exquisite pain it can be very tempting to initiate root canal therapy on a hunch without being absolutely certain that we have identified the correct tooth or even that the patient needs a root canal.
Generally, endodontic diagnosis is straightforward, but at times the truth can be elusive. If we move forward without being certain of the diagnosis we are living in a land called “Hope.” In such a place, access is easily made on the wrong tooth or may have been unnecessary. Unfortunate outcomes can ensue, including a patient still in pain, professional embarrassment, loss of patient trust and worse still the possibility for a professional malpractice claim.
With a comprehensive history and clinical examination, it is possible to routinely diagnose the offending tooth and/or to determine that treatment should be delayed for symptoms to localize or the patient referred for appropriate nonendodontic evaluation (TMD, neurology, ENT referral, etc.).1 Indications for RCT can be grouped into three categories: 1) vital irreversibly inflamed pulps, 2) necrotic pulps and 3) retreatment of previous endodontic failures. Each of these diagnoses has a relatively unique clinical presentation that distinguishes it from the others. In addition, there are definite clinical presentations that delineate odontogenic from non-odontogenic etiologies.2-4
This article was written to provide concise guidelines to help the clinician to decide when to initiate root canal therapy, delay treatment or refer for further evaluation. Due to the immense volume of subject matter related to Endo-Perio lesions and cracked tooth syndrome, these two topics and their relation to endodontic diagnosis are beyond the scope of this paper and will not be addressed.
Vital irreversibly inflamed pulps occur because of the myriad of cumulative insults to which the pulp is subjected. Cracking, caries, deep restorations, restorative materials, trauma (occlusal, thermal, chemical, mechanical), abrasion, attrition, are all causes of pulpal inflammation.5-7
Irreversible pulpal inflammation is manifest by spontaneous pain, thermal pain (cold and/or hot stimuli) that is either extreme or which lingers (more than a few seconds), and pain to chewing that is accompanied by one of the other symptoms. Localized pain with these characteristics is a primary indication for root canal therapy.
The wise practitioner will never accept a patient’s assertion as to the offending tooth without performing clinical tests to reproduce the patient’s chief complaint. In addition, it is risky and ill advised to rely just on one test (cold, percussion, etc). Every tooth suspected, including controls, should be tested to percussion, palpation, mobility, probing, cold and possibly heat. Additional tests as needed could include electric pulp testing, the bur test (entering a tooth without anesthesia to see if a response is elicited), selective anesthesia, transillumination and evaluation by the surgical operating microscope.
Thermal and electric pulp testing represent a relative and crude measure of pulp health by judging a patient’s response to a variety of perceived stimuli. The patient’s emotional makeup and status at the moment most certainly can affect pulp-testing results. False positives and negatives are possible. As a result, caution should be taken with interpretation of the results of thermal pulp testing results.
It is assumed that an adequate medical and dental history and comprehensive dental examination (including periodontal) precede any pulpal diagnostic procedures. That said, it is essential that a diagnosis is never made based solely on a radiograph.
In the hierarchy of evidence, the patient’s subjective history and clinical objective findings are primary. Radiographs are the final determinant to provide information in making the diagnosis and are given the least weight in making a diagnosis.8-10 Early stages of irreversible pulpitis generally do not display radiographic signs of pathology. Delaying treatment because of a lack of radiographic evidence is contraindicated in the face of overwhelming subjective and objective findings that RCT is indicated. Recognizing this subtle but important point can lead to more rapid diagnosis and treatment and ultimately pain relief for the patient.
A common daily scenario in endodontic practice involves the patient who is referred with a recently placed full crown on a tooth that had been sensitive to temperature (either hot or cold), spontaneously painful or painful to chewing prior to cementation. Instead of making the pain go away after crown cementation, the pain intensified either immediately or after some usually short period of time. Often times these patients will report that they were told that their tooth had a crack and that the pain they previously experienced would be relieved by crown placement. Crowning a tooth with these symptoms is obviously ill advised as many times the tooth already had irreversible pulpitis.
Symptomatic necrotic teeth, on the other hand, do not present with thermal sensitivity. Spontaneous pain (usually dull and throbbing) often accompanied by swelling and palpation sensitivity is virtually diagnostic for odontogenic pain resulting from a necrotic tooth. Sensitivity to percussion virtually always accompanies this diagnosis as well.
The diagnosis of an asymptomatic necrotic tooth (where the tooth is not sensitive to percussion or even palpation in the presence of periapical radiolucency) is always verified by thermal testing (no response to cold testing) to rule out normal anatomic spaces that might mimic periapical pathology and nonodontogenic periapical radiolucency.
The indications for re-treatment of a symptomatic failed root canal are usually not a diagnostic challenge. These teeth tend to be painful to percussion and palpation and have increased mobility. The patient often experiences a dull ache that is generally constant and increasing in intensity, duration and frequency over time. Swelling and apical palpation sensitivity is often present.
Pain that is of short duration, hours to days to weeks is generally odontogenic. Odontogenic pain most commonly worsens over time. It must be borne in mind that pain of odontogenic origin will not resolve spontaneously unless the tooth is extracted or root canal therapy initiated. Pulpal disease will ultimately manifest itself as pain that will not go away and possesses increased intensity, duration, and frequency and ultimately swelling. Such pain motivates the patient to urgent action in order to provide relief. Non-odontogenic pain sources have a more chronic and less localized nature.
If the patients’ chief complaint has been present for many months, has not changed much if at all, and does not move the patient urgently to seek treatment (all things being equal) the pain source is not of odontogenic origin.
Patience is counseled. If one is not sure RCT is indicated or which tooth is the offender, treatment is best delayed until symptoms localize. This is empowering. Symptoms will localize in time. Many are the teeth that have been started under stressful circumstances in order to relieve pain only to discover that the wrong tooth has been accessed or that the problem wasn’t odontogenic.
Conversely, many are the teeth that have needed treatment which for a variety of reasons have been left to smolder painfully where treatment was indicated from the start. Even after all necessary subjective, objective and radiographic examinations have been completed; some difficult cases defy diagnosis and explanation. Patients usually are willing to delay treatment until a definitive diagnosis can be made. Consultation is essential in such cases or where complex periodontal an
d/or TMD issues overlap with a possible endodontic problem.
Clinically, if a diagnosis of irreversible pulpitis has been made and the clinician has decided to access the tooth and perform a pulpotomy in one visit, several aids are recommended:
Enhanced visualization of the access cavity through the surgical operating microscope is most ideal. A rubber dam should always be employed. Intraosseous anesthesia is a necessity in many of these clinical cases.
Use of a viscous EDTA gel in the form of File-Eze (Ultradent, South Jordan UT, USA) can hold the pulpal in suspension until it can be floated out through sodium hypochlorite irrigation.
Use of an orifice opener such as the K3 Shapers is ideal from removing the coronal third pulp (SybronEndo, Orange, CA, USA) due to their resistance to breakage and cutting efficiency. These orifice openers can be used gently in most teeth to the middle third of a root bearing in mind that they should always be directed up toward the wall with the greatest volume of root structure and away from the furcation.
With practice, access and coronal third management can be made simple and predictable. In clinical use, the File Eze is placed in the chamber, the K3 Shapers are used to remove the pulp in the coronal third, irrigation ensues, File Eze is reapplied and the Shapers are used from larger tapers to smaller (.12, .10 and .08) to move down the canal to the point of initial root curvature. Large roots will usually easily accept a .12-tapered Shaper; smaller roots may only require a .08-tapered Shaper.
In summary, diagnostic indications for endodontic therapy in the case of irreversible pulpitis, non-vital pulp, and failed previous treatment have been presented. An emphasis on early diagnosis and referral as indicated has been made.
Dr, Mounce has no commercial interest in any of the products mentioned in this article.
Dr. Mounce lectures globally and is widely published. He is in private practice in endodontics in Vancouver, WA, USA. Amongst other appointments, he is the endodontic consultant for the Belau National Hospital Dental Clinic in the Republic of Palau. Korror, Palau (Micronesia). He can be reached at RichardMounce@MounceEndo.com.
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