A convenient way to ensure that the necessary pieces of the diagnostic puzzle have been collected is to use the mnemonic SOAP, which stands for Subjective, Objective, Assessment, and Plan/Procedure. It may not be necessary for experienced dentists to collect information in a regimented way but this time-honored method can be beneficial for new practitioners. With time and experience, practitioners can devise their own method of systematically gathering all necessary information.

There are some cases (for example, a patient with a toothache or a tooth with a periradicular radiolucency) where an endodontic diagnosis must be made. In other situations (for example, complex restorative treatment, a patient who complains of vague pain that could be of odontogenic origin, or cases where a pulp exposure is likely or suspected), it is advisable to make an endodontic diagnosis before beginning treatment.

Subjective information

As part of the diagnostic process, dentists should obtain as much information about the patient’s current situation as is possible. Typically, the patient’s chief complaint is the first subjective information obtained but practitioners also should ask open-ended questions designed to elicit as much information as possible; examples include “When did your problem start?” “Have you taken or had to take anything for the discomfort/pain?” and “Has this tooth ever bothered you before this most recent episode?” In particular, it is important to find out about the patient’s thermal sensitivity and whether cold or hot causes lingering pain, since lingering pain upon removal of the noxious stimulus many times indicates a diagnosis of irreversible pulpitis.

Objective information

The objective information obtained during the diagnostic phase should include the patient’s dental history and the results of clinical and radiographic evaluation and clinical testing. Recent dental work could indicate a non-endodontic source of the patient’s chief complaint—for example, a high restoration or sensitivity after a dental cleaning; in both instances, the patient may complain of cold sensitivity (a common symptom of pulpal degeneration), although endodontic treatment typically is not warranted.

Before beginning a clinical examination, it is helpful to ask if the patient can point to the offending tooth. Pulpal pain can be poorly localized, so it is equally important to determine if the patient cannot point to a specific tooth.¹ Occasionally, patients can localize the toothache only to a quadrant or, in extreme cases, to one side of the face. When the patient cannot determine which tooth is involved, arriving at a correct diagnosis becomes more difficult. This is frustrating for both the patient and the dentist, since it means that the scope of the examination must be expanded to include more teeth and, in some cases, even the opposite arch.

During the clinical examination, practitioners should take a cursory look at the patient’s entire mouth to gain a general understanding of the patient’s current dental situation. After obtaining this overview, the dentist should narrow the clinical examination and focus on the suspected tooth. What restorations are present (if any)? Is caries present? If so, is the extent of the decay sufficient to cause pulpal symptoms? What are the periodontal probing depths around the tooth? Is the tooth mobile? In other words, does the clinical picture match the patient’s chief complaint? If so, then the dentist should proceed to thermal and percussion testing. When the clinical picture does not match the patient’s reported complaint, it may be necessary to question the patient further to obtain a clearer picture of the situation.

During the examination process, a radiograph of the suspected tooth should be obtained and interpreted. Although many dental procedures are diagnosed based upon a single radiograph or digital image, it can be useful and beneficial to obtain more than one radiographic image. Multiple radiographs taken from different angulations can help the dentist to determine the course of the canal(s), the extent of caries (if present), the number of roots, and any unusual or abnormal root morphology.¹ Bitewing radiographs can be useful during the diagnostic phase because they help dentists to determine not only the extent and proximity of caries to the pulp chamber but also the height of both the pulp chamber and the interdental crestal bone.

Careful inspection of radiographs also can help dentists to determine a case’s complexity. If endodontic treatment is deemed necessary, practitioners should assess whether the case is within their capabilities and skill level or if it should be referred to a specialist. The AAE’s Case Assessment and Referral Form provides a checklist that can help practitioners determine if a particular case falls within their endodontic skill level and abilities, particularly with respect to radiographic evaluation and interpretation.²

It is important to note that radiographs cannot be used as the sole determining factor when deciding if endodontic treatment is indicated. The following case report illustrates this point.

Case report

A 31-year-old woman was referred to the Graduate Endodontic Clinic at Baylor College of Dentistry for evaluation of tooth No. 18. The patient reported developing a toothache in March 2005; at that time, her general dentist performed endodontic treatment on tooth No. 18. The following February, she developed a toothache again and her dentist prescribed an antibiotic. Figure 1 shows the initial preoperative radiograph taken at the Graduate Endodontic Clinic. There was a large radiolucency associated with the apices of tooth No. 18 and the distal root of tooth No. 19. There was minimal preparation for all of the canals and the radiolucency adjacent to the obturation material of the distal root suggested a missed canal. In addition, both mesial canals were filled inadequately.

Comparative testing revealed that teeth No. 18 and 19 were tender to percussion; tooth No. 19 also responded normally to cold testing. Tooth No. 18 was diagnosed with previously treated and symptomatic apical periodontitis, while tooth No. 19 was diagnosed with normal pulp and symptomatic apical periodontitis. Endodontic retreatment was performed on tooth No. 18. A postoperative radiograph shows nearly the entire lesion (Fig. 2).

Approximately 15 months later, the patient was referred for evaluation of teeth No. 18 and 19 (Fig. 3). The lesion was enlarged and now encompassed not only the apices of tooth No. 18 but both roots of No. 19 as well. Comparative testing was performed again. Tooth No. 19 responded normally to cold testing, although it was still tender to percussion and palpation. The patient was referred to an oral surgeon, who biopsied the lesion. Based on the clinical appearance and histological examination, a diagnosis of aneurysmal bone cavity was made, with a recommendation for clinical follow-up to ensure adequate healing.

This case illustrates the importance of confirming a radiographic diagnosis through endodontic testing. It would be tempting to skip thermal testing in this case, based on what superficially appears to be a lesion of pulpal origin. However, knowing from the patient’s history that tooth No. 18 does not respond to endodontic treatment (and retreatment), thermal testing led the clinician to correctly determine that this lesion was not of endodontic origin. 

Two tests are essential for an endodontic diagnosis: thermal testing and percussion and/or palpation tenderness. In most situations, dentists use cold for thermal testing; however, heat should be used if the patient’s chief complaint relates to heat. Many dentists refer to cold testing as vitality testing, even though vitality actually refers to the presence of blood flow to a tooth; rather, this test involves determining the presence of A-delta nerve fibers.³

There are several important points to remember regarding thermal and percussion/palpation testing. First, both of these tests are comparative in nature; one cannot arrive at an accurate diagnosis by testing the suspected tooth only. Second, these tests are intended to reproduce the patient’s chief complaint so that an assessment can be made concerning the health or disease of the tooth. One should test the suspected tooth, the two adjacent teeth, and the tooth contralateral to the suspected tooth. In other words, if tooth No. 19 is suspect, teeth No. 18–20 and No. 30 should be tested as well. The tooth contralateral to the suspected tooth should be considered a control tooth (that is, how the patient responds to thermal stimulus or percussion when a similar, normal tooth is tested). In fact, it is preferable to test the contralateral tooth first as a trial run so that the patient is familiar with a normal response.

Patients may report during thermal testing that they do not feel cold, only to reveal upon further questioning that they felt the cold but did not respond because they expected to feel pain. This confusion can be avoided by testing the contralateral tooth first, which not only aids the clinician in determining a “normal response” but ensures that the patient has understood the instructions.

There are various ways to perform the cold test. Using an air-water syringe to blow air onto the tooth is not a precise method. While many practitioners use this approach (and can get a response from it), it is uncertain if they can tell precisely which tooth produced the response. A somewhat more precise way to test for cold involves an ice stick, which is made by filling anesthetic cartridges with water, placing a piece of floss in the cartridge, and placing the cartridge in the freezer. When the time comes to use the ice stick, warm the cartridge in one hand and pull on the piece of floss to remove the ice stick. One drawback to this method is that the ice can melt and the cold water could run down the side of the tooth and contact an adjacent tooth.

A more reliable method for performing the cold test involves using a refrigerant, such as Endo-Ice (Coltene/Whaledent, Inc.) or Fridgident (Ellman International, Inc.). The refrigerant is sprayed onto a No. 2 cotton pellet until ice crystals form on the pellet, which is then placed on the facial surface of the tooth. Figure 4 shows ice crystals forming on the cotton pellet; Figure 5 shows correct placement of the chilled cotton pellet. The pellet should be placed where the greatest number of nerve fibers is located. Typically, this is the middle third of the clinical crown for posterior teeth and the border between the coronal and middle thirds of the clinical crown for anterior teeth.³ It is important to leave the chilled cotton pellet on the tooth for at least 10 seconds before deciding on the response.

 

 

A common misconception is that thermal tests cannot be performed on teeth with crowns or temporary restorations. These teeth can be cold-tested but it may be necessary to leave the cold in place for up to 10 seconds before the patient responds.⁴ A CO₂ ice stick may be used but doing so requires an extensive armamentarium (that is, a gas cylinder and plastic plunger).

 

When performing thermal testing, ask patients to raise their hand or say something to indicate that they feel the cold or heat, then have them lower their hand or indicate when the thermal sensation subsides. As stated earlier, lingering sensitivity (that is, more than 10–30 seconds) can indicate irreversible pulpal degeneration.

 

The electric pulp tester (EPT) is commonly used for endodontic diagnosis. The EPT does not measure the degree of health or disease of the pulp.³ Rather, it is a rough indicator of the presence or absence of nerves. Different response levels during electric pulp testing do not indicate different stages of pulp degeneration. Although it is understandable that the EPT report could be interpreted as an “objective” reading (such as 22/80), it is incorrect to interpret this reading as a judge of the health of the pulp. The reading merely indicates that a nerve responded to the electrical stimulus. Teeth diagnosed with irreversible pulpitis will still respond at some level with the EPT.

 

This is not to say that the EPT should not be used during endodontic diagnosis, since it is most useful in confirming a diagnosis of pulpal necrosis. In two separate studies, Seltzer et al found a poor relationship between teeth that responded and the histological condition of the pulp. However, the authors reported that teeth that did not respond to the EPT were more likely to be necrotic.^5,6 The EPT also can be used on calcified teeth, which may not respond to a cold stimulus but often will respond to an electrical stimulus if the pulp remains vital.

 

There are several potential drawbacks to using the EPT. First and foremost is that while patients “know” the correct response when cold touches a tooth, they may be unfamiliar with the sensation that the EPT produces. Also, the EPT can produce false-positive and false-negative responses. In addition, the probe has to touch natural tooth structure, making it difficult (or impossible) to use on full-coverage crowns.³

 

The other test that should be performed for endodontic diagnosis is percussion and/or palpation. The periradicular diagnosis is derived from the results of percussion testing and radiographic interpretation. Percussion involves testing for the presence of inflammation in the periradicular tissues.⁷ It is important to percuss the tooth not only axially (that is, along the long axis of the tooth) but also laterally (Fig. 6). Percussing a tooth along only its long axis may allow detection of inflammation only at the apex of the tooth, even though there can be inflammation anywhere along the root surface. Although tenderness to percussion may indicate pulpal degeneration (resulting in periradicular inflammation), other conditions, such as a high restoration, bruxism, clenching, or even sinusitis, may cause inflammation of the periodontium.¹

 

 

 

Using a finger, the dentist should tap on several teeth. If tapping lightly with a finger elicits a painful response, imagine how the patient would have responded if the practitioner had tapped forcefully with a mirror handle. If tapping the teeth with a finger does not cause discomfort for the patient, the dentist then can switch to using the mirror handle.

 

Assessment

In 2007, the American Board of Endodontics revised the pulpal and periapical diagnostic terminology. Briefly, two additional descriptions were added for irreversible pulpitis; the previously accepted term of periradicular was changed to periapical; acute and chronic periodontitis was changed to the more practical symptomatic and asymptomatic; and conditions with swelling or purulence were divided into acute and chronic apical abscess.⁸

 

After gathering all of the pieces of the diagnostic puzzle, it is time to view or assess the diagnostic picture. There are five pulpal diagnoses (two of which are further divided or refined): normal; reversible pulpitis; irreversible pulpitis; pulpal necrosis; and previously treated. Irreversible pulpitis has two additional descriptors, symptomatic and asymptomatic. Asymptomatic irreversible pulpitis exhibits no clinical symptoms, although there is inflammation produced by caries, caries excavation, trauma, and so forth.⁷ As the name suggests, symptomatic irreversible pulpitis indicates the presence of lingering pain or discomfort to thermal stimulus. Prior to the latest revision in terminology, previously treated was a catch-all diagnostic term for cases in which some form of endodontic treatment had been initiated; these ranged from a pulpotomy to completed nonsurgical root canal treatment. The new terminology has been refined to include the self-explanatory terms previously treated and previously initiated therapy.

 

In most cases, pulpal diagnoses are derived from the patient’s response to the applied thermal stimulus. Cold is the thermal test used most often; however, when heat is the offending stimulus, it should be used, applying the same criteria as cold testing when assessing pulpal status. Table 1 summarizes the responses to thermal stimulus for each of the possible pulpal diagnoses when endodontic treatment has not been performed.

 

 

 

The distinguishing feature between reversible and irreversible pulpitis is the duration of the pain or discomfort. The condition of the tooth is a factor when determining excessive lingering. For example, discomfort that lingers for three or four seconds would be considered excessive for an unrestored tooth but not for a tooth with extensive decay. As a general rule, if the pain or discomfort lingers longer than 5–10 seconds without any obvious etiology such as deep decay or gingival recession, then the diagnosis is irreversible pulpitis. Chart 1 is a flow chart for determining pulpal diagnoses when endodontic treatment has not been initiated.

 

 

 

There are five common periapical diagnoses plus one other diagnosis for special cases. The five common diagnoses are normal apical tissues; symptomatic apical periodontitis; asymptomatic apical periodontitis; acute apical abscess; and chronic apical abscess. The sixth diagnosis, which applies to special cases, is lesion of nonendodontic origin.

 

With the latest revision of diagnostic terminology, the terms acute periodontitis and chronic periodontitis have been replaced with the more descriptive symptomatic apical periodontitis and asymptomatic apical periodontitis. The descriptors acute and chronic have been added to “apical abscess” to indicate temporality. Chronic apical abscess is used to describe cases with a gradual onset of symptoms (that is, a sinus tract). Acute apical abscess is used to describe conditions with rapid onset and when patients demonstrate extreme tenderness to percussion and associated swelling. When a periapical lesion is associated with a tooth that responds normally to thermal testing, the term lesion of nonendodontic origin is used; this periradicular diagnosis would apply to the case report involving tooth No. 19. This term also is appropriate for cases of periapical cemental dysplasia.

 

Table 2 summarizes the key diagnostic characteristics for each periradicular diagnosis. Chart 2 is a flow chart for periapical diagnosis, similar to the pulpal diagnosis flow chart in Chart 1.

 

 

 

Summary

It is remarkable that dentistry still relies upon placing cold and tapping on a tooth to diagnose the need for nonsurgical root canal treatment. Although several technological tools can be used to aid in diagnosis, including laser Doppler flowmetry and conebeam tomography, it remains the dentist’s job to use tried-and-true diagnostic methodology and put the pieces of the puzzle together to form a clear diagnostic picture.^3,9 Only then can endodontic treatment be undertaken with the knowledge that no harm has been done.

 

Acknowledgements

The author wishes to thank Dr. Rob Roda for his guidance and suggestions for this paper.

 

Author information

Dr. Schweitzer is an assistant professor, Department of Endodontics, Baylor College of Dentistry, Texas A&M University System Health Science Center in Dallas.

 

References

            1.         Berman LH, Hartwell GR. Diagnosis. In: Cohen S, Hargreaves KM, eds. Pathways of the pulp, ed. 9. St. Louis: Mosby/Elsevier;2006:2-39.

            2.         AAE endodontic case difficulty assessment form and guidelines. Available at: http://www.aae.org/NR/rdonlyres/A5180AAE-02C2-45AB-8D46-81B033B31038/0/2006CaseDifficultyAssessmentForm.pdf. Accessed July 17, 2009.

            3.         Pitt Ford TR, Patel S. Technical equipment for assessment of dental pulp status. Endod Topics 2004;7:2-13.

            4.         Miller SO, Johnson JD, Allemang JD, Strother JM. Cold testing through full-coverage restorations. J Endod 2004;30(10):695-700.

            5.         Seltzer S, Bender IB, Ziontz M. The dynamics of pulp inflammation: Correlations between diagnostic data and actual histologic findings in the pulp. Oral Surg Oral Med Oral Pathol 1963;16:846-871.

            6.         Seltzer S, Bender IB, Ziontz M. The dynamics of pulp inflammation: Correlations between diagnostic data and actual histologic findings in the pulp. Oral Surg Oral Med Oral Pathol 1963;16:969-977.

            7.         Sigurdsson A. Pulpal diagnosis. Endod Topics 2003;5:12-25.

            8.         American Board of Endodontics pulpal & periapical diagnostic terminology. Available at: http://www.aae.org/NR/rdonlyres/0A9E773B-506D-4B63-884E-DA68381CEAB0/0/ABETerminologyMay2007.doc. Accessed May 2, 2009.

            9.         Cotti E, Campisi G. Advanced radiographic techniques for the detection of lesions in bone. Endod Topics 2004;7:52-72.

 

Manufacturers

Coltene/Whaledent, Inc., Cuyahoga Falls, OH; 800.221.3046; www.coltenewhaledent.com

Ellman International, Inc., Oceanside, NY; 800.835.5355, www.ellman.com

 

 

 

 

Granuloma or cyst

A patient has just asked you, “What is that black spot (or shadow) on my radiograph?” What do you tell him or her? Does it represent apical periodontitis? A granuloma? A cyst? In fact, all of these diagnoses are possible.

 

It is important to note that apical periodontitis is a clinical diagnosis, indicating inflammation at the peri-apex of a tooth.¹ Most often, the inflammation is due to pulpal degeneration. On the other hand, granuloma and cyst are histological diagnoses; therefore, it is inaccurate to say that a periapical lesion is a granuloma, cyst, or scar without the benefit of a biopsy obtained during endodontic surgery.

 

In any event, if the tooth is to be retained, endodontics is the treatment of choice. It is not necessary to take a biopsy of the periapical lesion before initiating treatment.

 

In cases where an endodontically treated tooth has a periapical lesion and the patient is symptomatic, several issues should be considered before recommending a treatment. The decision to perform endodontic surgery (or apicoectomy) rather than endodontic retreatment is complex. The most important considerations are the quality of the obturation and whether it can be improved through retreatment. Retreatment should be selected if it can improve or correct the current deficiencies; if retreatment is not feasible or practical, then endodontic surgery will be necessary to retain the tooth.

 

According to studies on the nature of periapical lesions, most biopsied lesions are granulomas, followed by cysts. The percentage of periapical lesions diagnosed as granulomas ranges from 50–77%.^1-3 If abscesses (a collection of polymorphonuclear leukocytes within a granuloma) are combined with granulomas, this percentage jumps to more than 80%. The incidence of cysts in these same studies is approximately 20%.^1-3 Although the overwhelming majority of periapical lesions are diagnosed as either granulomas or cysts, it is prudent to confirm the clinical diagnosis or impression through biopsy in all cases.

 

Finally, can a granuloma or cyst be diagnosed via radiographs? Lalonde suggested that lesions larger than 2 cm in diameter or more than 200 mm² are more likely to be a cyst.⁴ More recent studies have supported this concept while cautioning that size is not a consistent or reliable predictor in diagnosing a cyst radiographically.^5,6

 

References

            1.         Ramachandran Nair PN, Pajarola G, Schroeder HE. Types and incidence of human periapical lesions obtained with extracted teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;81(1):93-102.

            2.         Schulz M, von Arx T, Altermatt HJ, Bosshardt D. Histology of periapical lesions obtained during apical surgery. J Endod 2009;35(5):634-642.

            3.         Love RM, Firth N. Histopathological profile of surgically removed persistent periapical radiolucent lesions of endodontic origin. Int Endod J 2009;42(3):198-202.

            4.         Lalonde ER. A new rationale for the management of the periapical granulomas and cysts: An evaluation of histopathological and radiographic findings. J Am Dent Assoc 1970;80(5):1056-1059.

            5.         White SC, Sapp JP, Seto BJ, Mankovich NJ. Absence of radiometric differentiation between periapical cysts and granulomas. Oral Surg Oral Med Oral Pathol 1994;78(5):650-654.

            6.         Carrillo C, Penarrocha M, Ortega B, Marti E, Bagan JV, Vera F. Correlation of radiographic size and the presence of radiopaque lamina with histological findings in 70 periapical lesions. J Oral Maxillofac Surg 2008;66(8):1600-1605.