Endodontic Diagnosis: There’s an App for That!

INTRODUCTION
Before you run and pick up your iPhone to download the endodontic diagnosis app, I must clarify that the app I am referring to is the “application,” in the true sense of the word for endodontic diagnosis!

I graduated from dental school with a “tooth mechanic” mentality. Then, for the better part of 25 years since dental school, I have been developing an “oral physician” thought process when it comes to practicing dentistry, and specifically with regard to endodontic diagnosis. Early in my dental career as a tooth mechanic, I would make an endodontic diagnosis by primarily accessing the limited information that was acquired through patients’ subjective perspectives of their dental problem (chief complaint) and a dental radiograph. I would have little consideration of the patients’ systemic involvement in their oral health, or in understanding the importance of performing other objective endodontic tests. In thinking like an oral physician, one must understand that oral conditions can affect the systemic health of a patient as well as the systemic health directly or indirectly affecting an individual’s oral health. With the mindset of an oral physician, I now take a much broader perspective in developing the proper endodontic diagnosis. This is done by acquiring more information from accessing patients’ medical and dental histories and understanding the their chief complaint in conjunction with performing specific objective endodontic clinical tests.

My methodology of initiating endodontic diagnosis is similar to the television game show Jeopardy! The Jeopardy! contestant is given the answer, and he or she must provide the question. The patient’s chief complaint is the answer, and my questions are: What are the etiology, diagnosis, and subsequent endodontic treatment (if applicable)? The patient’s answer is subjective (such as “my tooth hurts to bite on”), and the clinician’s question is objective, using the correct clinical diagnostic procedures (such as testing the tooth or teeth in question to percussion, along with 4 other endodontic objective tests). Incorporating the data from these objective tests in conjunction with any pertinent information from the patient’s medical and dental history, one can properly determine if the diagnosis is of endodontic origin and requires endodontic treatment.

In order to better understand this endodontic diagnosis app, I have a presented 2 virtual clinical case scenarios below. They are written as if these patients are being seen by virtual dentists in their clinical operatory. I have added didactic commentary to these virtual patients’ work-up by the virtual dentists in order to help highlight important points and to further enhance your own clinical endodontic diagnostic skills.

CASE 1
Odontogenic Diagnosis
A 30-year-old virtual female patient presents to the virtual dentist with a medical history filled out. This patient is reporting no history of rheumatic fever and associated heart murmur, bleeding disorders, diabetes, hepatitis, AIDS, or other significant diseases or allergies to medications.

Commentary: It is important for you to specifically review the above stated symptoms and diseases with the patient, even if she has given a negative response on the medical form. Patients may think that they do not need to inform the dentist about any relevant medical history because, in their mind, they are just being seen for a “tooth problem.” The medical history of heart murmur, bleeding disorders, diabetes, hepatitis, and AIDS can have a direct or indirect effect on the oral health of this patient and, of course, subsequently on your actual treatment plan. It is also important when obtaining the health history information that the dentist take the patient’s blood pressure (Figure 1) and pulse; especially on any new patients, or patients with a history of high blood pressure.

Our virtual patient presents with a dental history of previous minor restorative treatment and a chief complaint of, “My lower right tooth hurts to cold.” The dentist proceeds to do a clinical exam and discovers caries on tooth No. 29. A periapical radiograph of tooth No. 29 (Figure 2) is taken. The caries on tooth No. 29 leads to the diagnosis that this tooth is the etiology of the patient’s chief complaint. The dentist’s treatment plan is to remove the caries and to place a filling if the pulp is not exposed, or the addition of endodontic treatment if pulp is exposed during treatment.

Figure 1. Wrist sphygmomanometer.	Figure 2. Perapical radiograph of tooth No. 29.
Figure 3. Endo Cool Spray (Henry Schein) should be used to test teeth for cold sensitivity.	Figure 4. Electric Pulp Tester (SybronEndo).

Commentary: Although the caries on tooth No. 29 is in need of dental treatment, tooth mechanic mentality comes into play as the dentist is immediately drawn to the caries as the etiology of the patient’s pain. Dental school has thought us well to treat caries as seriously as a heart attack. Although dental caries has one of the slower disease onsets in the human body, we are trained that the caries must be removed immediately without any further odontogenic diagnostic evaluation. Interestingly, we have also been “trained” since leaving our dental school education that the dental radiograph is all we need to make a complete diagnosis!

Understanding that there are 4 additional objective endodontic clinical tests (5 in total) that, in conjunction with dental radiographs, need to be performed in order to properly diagnose this patient, the virtual dentist continues the examination on this virtual patient. These additional tests include: (1) application of cold (Figure 3), electric pulp testing (EPT) (Figure 4), and application of heat (Figure 5). If the tooth does not respond to cold or EPT, and it tests positive for pulp vitality, then; (2) percussion tests for the status of the periodontal ligament (note that this may include bite testing); (3) palpation of the gingival tissue and cortical and medullary bone for infection and inflammation; and (4) periodontal examination, to include probing and tooth mobility.

Along with the current periapical radiograph, it may be necessary to take multiple-angle periapical films, bite-wing radiographs, and cone beam tomography, if indicated.

The dentist further examines the virtual patient using the additional 4 objective tests. Cold is placed on teeth Nos. 28, 29, and 30: tooth No. 28 tests normal (cold dissipates within a few seconds); tooth No. 29 does not respond to cold test, EPT, and heat test; and tooth No. 30 elicits a lingering response to cold test beyond 5 seconds (reproducing the patient’s chief complaint). Percussion test, palpation test, periodontal examinations are within normal limits on teeth Nos. 28, 29, and 30.

Figure 5. Either a System B (SybronEndo) or a Touch’n Heat (SybronEndo) unit can be used to test teeth for heat sensitivity.

Figure 6. A sample of an endodontic diagnostic work-up form.

Figure 7. Periapical radiograph of tooth No. 22.

Commentary: It is important to note that all objective testing results must be written down, not just committed to memory (Figure 6). After reviewing all the test data from the 5 objective clinical endodontic tests, the dentist determines that tooth No. 30 has an irreversible pulpitis (as determined by lingering cold beyond 5 seconds) and tooth No. 29 is necrotic. The treatment plan is to first complete endodontic treatment on tooth No. 30 in order to eliminate the patient’s pain. Note: A periapical radiograph of tooth No. 30 along with a bite-wing should be taken prior to any endodontic treatment on tooth No. 30. Then, the dentist can restore No. 30, or perform endodontic treatment on tooth No. 29, along with the caries removal, since it is testing necrotic and restore separately or injunction with tooth No. 30. If the above 5 objective endodontic tests were not completed on this patient, the wrong tooth (No. 29) would have been endodontically treated and the patient’s chief complaint would not have been properly diagnosed.

Pulpal Diagnosis
Nociceptors are sensory receptors that respond to stimuli by sending nerve signals to the brain. This stimulus can cause the perception of pain in an individual. The pulpal nerve fibers, A-Delta and C-Fibers, are nociceptors.^1,2

Basic inflammatory pulp diagnosis is reversible, or irreversible, pulpitis. Reversible pulpitis is pain from an inflamed pulp that can be treated without the removal of the pulp tissue. It should be noted that this is not a disease, but a symptom. The classic clinical symptom is a sharp, quick pain that subsides as soon as stimulus is removed. Physiologically, it is the A-Delta fibers that are firing, not the C-Fibers of the pulp.³ A-Deltas fibers are the myelinated, low threshold, sharp/pricking pain nerve fibers that reside principally in the pulp-dentin junction. They are stimulated by cold and EPT and cannot survive in a hypoxic environment. Reversible pulpitis does not involve unprovoked (spontaneous) response.

Irreversible pulpitis is an inflamed pulp that cannot be treated except by the removal of the pulp tissue. Classic clinical symptoms are lingering of cold/hot stimulus greater than 5 seconds and/or patient reports of spontaneous tooth pain. Physiologically, it can be the A-Delta fibers and/or the C-Fibers firing neural impulses. C-Fibers are the unmyelinated, high threshold, aching pain nerve fibers. They are distributed throughout the pulp. They are stimulated by heat and can survive in a hypoxic environment.

Pulpal necrosis can result from an untreated irreversible pulpitis or immediately after a traumatic injury that disrupts the vascular system of the pulp. A necrotic pulp does not respond to cold tests, EPT, or heat tests.

It is important to note that heat and cold tests do not jeopardize the health of the pulp.⁴ Also, teeth with porcelain or metal crowns do conduct temperature and can therefore be tested for pulpal vitality with cold or hot. There is often confusion on what the numerical readings on an electric pulp tester represent. Although EPT can establish pulp vitality, the numerical readings cannot be used to determine the overall health of the pulp.⁵ An example of this is as follows: if tooth No. 8 has an EPT reading of 12, and tooth No. 9 has an EPT of 24; tooth No. 8 pulp status is not considered twice as healthy as No. 9. When using an EPT, be aware that teeth with metal restorations can give false positive or negative readings.

CASE 2
Nonodontogenic Diagnosis
A 65-year-old virtual male patient presents to the virtual dentist with a medical history filled out reporting no history of rheumatic fever and associated heart murmur, bleeding disorders, diabetes, hepatitis, or other significant diseases or allergies to medications. When the dentist reviews the health history form with him, the patient states that he has not been seen by a physician in more than 5 years. Patient presents with a dental history of previous restorative and endodontic treatment and a chief complaint of “my lower left eye tooth hurts.”

The dentist then proceeds to do a clinical oral exam. Understanding that the 5 objective endodontic clinical tests need to be performed before formulating a diagnosis (as learned from the previous case!), the virtual dentist performs these on teeth Nos. 21 to 23. All teeth test within normal limits to cold, EPT, percussion, palpation, mobility, and periodontal probings. A periapical radiograph of tooth No. 22 is taken (Figure 7), and a small previously placed restoration on tooth No. 21 is noted, but there is no evidence of periodontal disease on teeth Nos. 21 to 23.

Commentary: Although all the teeth tested are within normal limits, and the patient continues to insist that tooth No. 22 is the cause of his jaw pain, the dentist must heed (not override) the objective clinical finding(s) and initiate endodontic treatment on tooth No. 22. At this point the dentist should go back and retest the tooth (or teeth) in question (using the 5 diagnostic tests) to confirm that there is no further stimulation of the patient’s chief complaint. One should recognize that it is not uncommon to test the tooth (or teeth) in question 3 different times during the same patient appointment to properly ensure against any testing inaccuracies.

The retesting by our virtual dentist also demonstrates results that teeth Nos. 21 to 23 are within normal limits to the 5 objective tests. The conundrum of the diagnosis is not clear, but the patient does describe toothlike pain and, therefore, the etiology must be tooth No. 22. As a result, the virtual dentist makes the diagnosis of pulpitis and explains to the patient that a root canal treatment needs to be performed on tooth No. 22, without any consideration that there is no decay or previous restorative treatment.

Commentary: This total disregard of a tooth (or teeth) testing within normal limits to the objective clinical exam, in favor of creating a diagnosis and treating from the subjective findings, is not uncommon. After all, if you were trained as a tooth mechanic, as I had been, any pain in the mouth has a very high percentage of being tooth-related.

Whenever the objective diagnostic tests either do not correlate with the subjective patient symptoms or are within normal limits, you must take a mental step back to re-evaluate the etiology and diagnosis. In this case, with the objective tests being normal, it is important to start considering nonodontogenic sources of pain. In this case, if you asked this patient what causes the pain, he would state that it is in the lower left jaw; and the tooth hurts when he walks up the stairs, or when engaging in any moderately strenuous physical activity. It is with this knowledge that the clinician must be thinking of a possible cardiac etiology.

Sandler et al⁶ reported that conditions of cardiac induced jaw pain show approximately 10% of cases refer pain to the mandible. This virtual patient needs to be referred to a cardiologist for a work up. Note that if the root canal was initiated on tooth No. 22, not only would this endodontic treatment not resolve the patient’s chief complaint; this patient would be in serious health risk of a possible heart attack or cardiac arrest.

Heterotopic pain or secondary pain are symptoms that are perceived to originate from a site that is different from the actually the source of the pain.⁷ That is why from an endodontic diagnostic prospective, when teeth test within normal limits to the 5 objective tests, the clinician must begin to understand that the source of the pain may be different from the site of the pain.

In the 2 virtual case studies presented, the first case clearly demonstrated that the site and source of the pain was the same. The objective tests correlated with the patient’s chief complaint of cold sensitivity on the tooth and thus an odontogenic irreversible pulpitis diagnosis was correctly made. In the second case scenario, the patient’s chief complaint of tooth pain in the lower left mandible region did not correlate with the objective endodontic testing performed. The site of the pain was tooth No. 22, but the source of the pain was cardiac. Unfortunately, the latter case study is the reason many unnecessary dental treatments are performed with no resolution of a patient’s subjective preoperative symptoms.

ODONTOGENIC VERSUS NONODONTOGENIC DIAGNOSIS
It is important to note that there are many nonodontogenic pain symptoms that mimic endodontic-type symptoms.⁷ If a patient subjective description of pain is “tingling,” “electriclike,” “burning,” or “hurts on both sides of my face,” the etiology may be nonodontogenic of origin.

The gray areas of diagnosis appear when there are inconsistencies between a patient’s subjective description and clinician’s objective diagnostic tests. If a clinician feels the diagnosis is odontogenic, but cannot localize the etiology, he or she should consider prescribing medication(s) to help localize the symptoms or refer the patient to a dental specialist for further evaluation.

Prescribing anti-inflammatory or antibiotic medications and then having the patient back for re-evaluation can sometimes help in achieving a definitive diagnosis. The difficulty with this is that some dentists believe that, unless a high-speed drill is involved, simply prescribing medication is not really “treating” the patient. Yet, in the field of medicine, if physicians prescribe medicine(s), they are treating their patient properly. A clinician who renders treatment, without identifying etiology, is more likely to have a patient quickly lose confidence; this may be due to treatment that does not relieve any symptoms. A dentist should never feel defeated (or any less of a practitioner) if a patient referral needs to be made to an endodontist. The patient will respect and appreciate a dentist who knows his or her clinical limits on a particular case.

The use of selective anesthesia can also assist in reaching a diagnosis. Although there are exceptions, if local anesthesia dissipates the patient’s pain, the etiology is generally odontogenic. If local anesthesia is not effective in eliminating pain, the etiology is usually nonodontogenic. When a dentist implements selective anesthesia as a part of the diagnostic procedures, it should be the last test performed. This is because the tooth (or teeth) involved will not be able to be further tested for sensitivity at this appointment.

Another helpful aid in diagnosis is to have the patient keep a short daily diary. Patients often describe pain in generalities. It is not until they are asked to make notes of specific incidences of pain that they can better communicate to the dentist. Examples that I have seen in patients’ diaries include the patients describing pain waking them up at night (spontaneous, diagnosis: irreversible pulpitis), or in the morning when they have their coffee (C-Fibers stimulation, diagnosis: irreversible pulpitis) but is quickly relieved when they have their cold orange juice. The patient is usually requested to keep such a diary for a week.

If, after a thorough review of diagnostic tests, the dentist feels that the etiology is nonodontogenic, the dentist should refer the patient to a physician (usually a neurologist) or a dental specialist (oral surgeon or maxiofacial pain specialist) for further evaluation and possible treatment.

IN SUMMARY
Developing the clinical app for proper endodontic diagnosis requires a dentist to think like an oral physician. This type of thinking requires the clinician to diagnosis from a broader base of information. An endodontic diagnosis cannot be formulated by the subjective patient’s description (chief complaint) and a dental radiograph alone. The information from the medical and dental history (that includes taking and recording the patient’s blood pressure and pulse), along with 5 odontogenic objective tests: pulp testing, percussion (may include bite testing), palpation, periodontal probing/tooth mobility, and radiographic examinations, are paramount.

When a dentist evaluates the data from these 5 objective tests, along with the medical and dental history in conjunction with the patient’s chief complaint, the site of the pain must correlate with the source of the pain. If there are inconsistencies with the site and/or source correlation of pain, one must not proceed with dental treatment in any way. The dentist must re-evaluate the testing data and consider the possibility of nonodontogenic origin of pain. When dealing with nonodontogenic pain, the patient will often subjectively state that the pain is coming from a specific tooth (or teeth), but the tooth (or teeth) in question will test within normal limits to the 5 objective endodontic tests.

Lastly, if a dentist has difficulty in deriving a definitive odontogenic or nonodontogenic diagnosis, he or she should feel comfortable referring the patient to an endodontist, oral surgeon, or a maxillofacial pain specialist for further patient evaluation.

References

1. Loeser JD, Treede RD. The Kyoto protocol of IASP Basic Pain Terminology. Pain. 2008;3:473-477.
2. Mattscheck D, Law AS, Nixdorf DR. Diagnosis of nonodontogenic toothache. In: Hargreaves KM, Cohen S, Berman LH, eds. Cohen’s Pathways of the Pulp. 10th ed. St. Louis, MO: Mosby Elsevier; 2011:52.
3. Kim S. Neurovascular interactions in the dental pulp in health and inflammation. J Endod. 1990;16:48-53.
4. Rickoff B, Trowbridge H, Baker J, et al. Effects of thermal vitality tests on human dental pulp. J Endod. 1988;14:482-485.
5. Lado EA, Richmond AF, Marks RG. Reliability and validity of a digital pulp tester as a test standard for measuring sensory perception. J Endod. 1988;14:352-356.
6. Sandler NA, Ziccardi V, Ochs M. Differential diagnosis of jaw pain in the elderly. J Am Dent Assoc. 1995;126:1263-1272.
7. Okeson JP, ed. Orofacial Pain: Guidelines for Assessment, Diagnosis, and Management. Carol Stream, IL: Quintessence Publishing; 1996:8,69.

Dr. Bahcall is an associate professor at Midwestern University College of Dental Medicine. He is a Fellow in both the American and International Colleges of Dentists, and a Diplomate of the American Board of Endodontics. He has been the recipient of outstanding teaching awards, has published numerous scientific articles, as well as written chapters for endodontic textbooks, and lectures on endodontics internationally. He can be reached at (630) 515-7493 or at jbahca@midwestern.edu.

Disclosure: Dr. Bahcall reports no disclosures.