Questions to Ask Prior to Root Canal Treatment

When one discusses clinical endodontic techniques, it often tends to involve a drill, an endodontic file, or an obturator. But a noninvasive procedure that must not be overlooked, and that which precedes the aforementioned, is that of diagnosing and treatment planning the case at hand.

In this article, the author will review diagnostic techniques in the form of very important fundamental questions that should be asked, along with clinical criteria to consider, prior to every potential endodontic case.

QUESTION 1
What Is the Origin of the Pain?
While a patient may have oral pain and point to the teeth, the clinician needs to determine if the pain is of an endodontic origin. Perhaps the pain is due to nonendodontic sources such as dentin hypersensitivity, occlusal trauma such as clenching/grinding, or is sinus-related. So, even if the patient points to his or her teeth, the clinician must always keep an open mind when diagnosing the symptoms. One cannot assume it is always endo-related.

Criteria to Consider
Pardon the obvious statement, but endo should be performed only if the clinician is certain that the pain is of an endodontic origin. Such pain should meet the fundamental criteria for pain of pulpal, or apical, origin. This, at least in part, includes symptoms such as lingering pain to hot or cold, no response to pulp tests (with exceptions), and cases with apical pathology (Figure A in the Table). One of the simplest but most important techniques to should use in order to diagnose the pulpal state is a cold test with Endo-Ice (Hygenic) (Figures 1 and 2). To determine common signs of pain of neuromuscular or parafunction origin, one should perform and evaluate the following: palpate for tender or tense masticatory muscles (Figure 3) and look for occlusal wear facets (Figure B in the Table) or nonlocalized pain that either wakes the patient up at night or is present upon waking up in the morning.

Figure 1. Cotton pellet sprayed and soaked with Endo-Ice (Hygenic).	Figure 2. Cold cotton pellet placed on tooth to test vitality.
Figure 3. Palpation of masticatory muscles.	Figure 4. Transilluminator (Microlux Transilluminator [AdDent]) used to evaluate for coronal fractures.

Figure 5. Enhanced magnification with transillumination of a mandibular molar, highlighting a vertical fracture.

QUESTION 2
Is the Tooth Worth Saving?
While the endodontic procedure may be a nonissue, as part of the routine diagnostic procedure, one must still ask if the tooth is worth saving.

More specifically, could the tooth be predictably and soundly restored? Obviously, there is no point in performing a root canal on a nonrestorable tooth or perhaps a wisdom tooth that serves no functional or restorative purpose with respect to occlusion. Is there sufficient tooth structure supragingivally to restore? Is the tooth in question significantly fractured? Is the cost of the procedure, including post-endo restorations something the patient can afford?

Criteria to Consider
The tooth in question would be worth saving if there is sufficient and sound coronal tooth structure to retain a restoration. At the very least, enough sound tooth structure (dentin/enamel) should be present for the preparation of an adequate (1.5 to 2.0 mm) ferrule (Figure C in the Table). One cannot rely solely on a post-and-core to retain a coronal restoration, no matter which restorative material and technique are used.

A vertical fracture may greatly affect the prognosis and the ability to save a tooth. A general rule of thumb is that if a vertical fracture extends to the pulp floor/cemento-enamel junction (CEJ), prognosis is poor (Figure D in the Table). Even if such teeth were to get a resin-bonded core and full-coverage restorations, they would still be very compromised. One cannot over emphasize the importance of looking for coronal fractures prior to every root canal. An easy way to do so is via transillumination (Microlux Transilluminator [AdDent]) (Figure 4) of the buccal or lingual aspects of the tooth.

Enhanced magnification with illumination, such as quality loupes with headlights (ie, Designs for Vision or SurgiTel) or a dental microscope (such as Carl Zeiss or Global Surgical), is key during your diagnostic procedure for examining hairline fractures (Figure 5).

Another indicator of a fracture is an isolated periodontal pocket (Figure 6) and/or a vertical isolated bony defect that could be seen in a 3-D scan (Figure 7). Vertical bone loss and/or an isolated periodontal pocket may not always be definitive of a fracture, but they are a very likely indication of one.

Now, dentistry is not like mathematics where 2 + 2 always equals 4. In other words, nothing is etched in stone, and having stated the above, there are always exceptions. An example may be in patients at risk of bisphosphonate-related osteoradionecrosis of the jaw resulting from an extraction. But the rule of thumb is this: do not save the tooth or perform endodontics if the tooth is not structurally salvageable.

Figure 8. Tooth No. 3 with a poor periodontal prognosis.	Figure 9. Dental loupes with enhanced illumination (such as Designs for Vision, SurgiTel, or Orascoptic).

QUESTION 3
What Is the Long-Term Prognosis of the Tooth?
Once it is determined that the symptoms and/or pathology are of endo­dontic origin and the tooth is worth saving, the clinician needs to ask if the long-term prognosis for the tooth is good. Instead of just considering the endodontic prognosis, we should also ask about the restorative and perio­dontal prognosis.

Criteria to Consider
The success for routine initial root canal treatment (RCT) in a tooth that is ideally and well restored is exceptionally high; easily a more than 90% success rate for a period of many years. We may be able to predictably and successfully perform the RCTs, but the tooth should also have a good long-term restorative and periodontal prognosis. One must always consider if it is worth performing the root canal on a tooth that is restorable but may be in a poor state of periodontal health (Figure 8 and Figure E in the Table).

If the combined prognosis for the tooth is not good, then perhaps alternatives such as a fixed bridge or an implant should be considered. Hence, if the long-term prognosis for a sound and cost-effective alternative is better than that for saving the tooth, the clinician needs to question whether it is worth proceeding with the endo­dontic treatment. We need to always think of the big picture and avoid focusing only on endodontics.

One should also consider the combined financial costs of saving the tooth (ie, endo, post, core, possible crown lengthening, and a crown) versus an alternative (ie, single dental implant). It is reasonable, if not expected, that you discuss the variety of possible and viable treatment options with every patient.

QUESTION 4
Is This Endo Within the Clinician’s Expertise and Abilities?
By the time we get to this part of the pretreatment analysis, we have determined that the patient requires endodontic treatment, the tooth is structurally and periodontally sound, and the overall prognosis and cost is better than any other options that may be available.

So, we must now ask, as the treating clinician, one more set of questions as part of the diagnostic procedure.

• Am I proficient in performing the endodontic procedure?
• Do I have the necessary instruments (Figure F in Table) required to perform the RCT at, or above, the standard of care?
• Is the procedure at hand, such as calcified and curved roots (Figure G in Table), endodontic retreatment or endodontic apical surgery, within the realm of a general dentist, or not?
• If this treatment was being done on a close family member, would I perform the root canal or would I refer to an endodontist?

Criteria to Consider
This, in part, is operator dependant, as some dentists may limit their RCTs to more simple anterior or premolar teeth. And others may be comfortable and capable of performing sound RCTs on molars, including ones with complex anatomy. One must know his or her own limits as a clinician. It is honest and honorable to tell patients that they would be better treated by an endodontist in certain cases.

For most endodontic procedures, one should have the right equipment, and there are many tools needed for proper endo treatment. However, there are a couple of more important tools to consider. The first important tool is enhanced magnification with illumination. To locate calcified canals, the infamous but almost always present MB2 canal, or a hairline vertical fracture, one must be able to see inside that little endo access. At the very least, using quality loupes with a headlight (ie, Designs for Vision, SurgiTel, Orascoptic) would be the minimal equipment required (Figure 9). If loupes are used without illumination, then that little dark endo access of a hole in the tooth will appear larger, but it will still be a dark hole. If one wants to take endodontics to the next level to be able to perform more complex cases, and to see things better and with less effort, then using a dental microscope (ie, Carl Zeiss, Global Surgical) is a must (Figures 10 and 11). Several years ago, this may have sounded far-fetched for GPs, but that is not the case any longer.

The second main tool you need is the right endodontic file system for the case at hand. If you intend to treat a calcified and/or curved tooth (Figure G in Table), then you should have the appropriate files. These may include NiTi files that are of a narrow taper, very flexible, and designed to follow canal curvatures (such as ProGlider [Dentsply Sirona Endodontics], ESX Expeditor [Brasseler USA], or X-Plorer [CLINICIAN’S CHOICE Dental Products]) (Figures 12 and 13). Thanks to the improved materials and engineering of NiTi files, endodontic treatment is now easier, safer, and more predictable.

CLOSING COMMENTS
As dentists, it is in our sincere nature to get our patients comfortable and save their teeth. Often, this involves an endodontic procedure. But before we pick up a handpiece and start RCT, we must always stop for a moment and as part of our endo diagnostic procedure, analyze the bigger picture.

The simplest way is to pause and ask the following: Does the patient actually need endodontic treatment? If so, is the tooth even salvageable? If it is, then what is the combined endo­dontic, restorative, and periodontal prognosis for the tooth, and is there a better and/or less expensive alternative? Finally, if endodontic treatment is still necessary and recommended, are you the person to perform it or should it be referred to an endodontist? Remember, please think, what you would do if it was your own mother.

Suggested Reading
Burry JC, Stover S, Eichmiller F, et al. Outcomes of primary endodontic therapy provided by endodontic specialists compared with other providers. J Endod. 2016;42:702-705.
Cameron CE. The cracked tooth syndrome: additional findings. J Am Dent Assoc. 1976;93:971-975.
Hargreaves KM, Berman LH. Cohen’s Pathways of the Pulp. 11th ed. St. Louis, MO: Elsevier; 2016.
Rotstein I, Simon JH. Diagnosis, prognosis and decision-making in the treatment of combined periodontal-endodontic lesions. Periodontol 2000. 2004;34:165-203.
Torabinejad M, Walton RE, Fouad AF. Endodontics: Principles and Practice. 5th ed. St. Louis, MO: Elsevier; 2015.
Torabinejad M, Goodacre CJ. Endodontic or dental implant therapy: the factors affecting treatment planning. J Am Dent Assoc. 2006;137:973-977.

Dr. Haas is a certified specialist in endodontics and lectures internationally. He is a Fellow of the Royal College of Dentists of Canada and is on staff at the University of Toronto Faculty of Dentistry and the Hospital for Sick Children. He maintains a full-time private practice limited to endodontics and microsurgery in Toronto. He can be reached at (416) 787-5021 or via the website haasendoeducation.com.

Disclosure: Dr. Haas reports no disclosures.

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