Pulp-lexed?

by Stephen P. Niemczyk, DMD

Everyone enjoys a great mystery, whether on the big screen, small screen, tablet, or for the nostalgic, in a hardcover book. Assessing each clue in an attempt to deduce the correct solution before the author discloses it is every amateur sleuth's ambition. However, when the mystery is sitting in your chair and the storyline becomes clouded by contradiction and discomfort, even Sherlock Holmes would find the challenge daunting.

Indeed, one of the most frequently asked questions in any dental continuing education course is "When do I initiate root canal treatment if there are no radiographic signs?" Striving to do no harm, we vacillate between over, under, and -- in the worst-case scenarios -- incorrect treatment plans, all in an attempt to alleviate our patients' chief complaints.

Fortunately, most painful presentations have simple etiologies, neuralgia and facial pain syndromes notwithstanding. Patients will readily supply us with the appropriate clues; we simply have to listen more judiciously for indications that the pulp is irreversibly damaged. For that assessment, we could employ CLIP© when evaluating pain.

Commencement: When did the sensitivity/pain first occur? What were you doing at the time? (Eating, drinking, exercising, sleeping) Did you have recent dental work done? (restorations, crowns)

Localization: The patient will point to a specific tooth or area. This serves to focus our diagnostic testing and discovery, and becomes especially crucial when evaluating referred pain.

Intensity/duration: Is the discomfort tolerable with OTC medications, or is it life altering to the point that narcotics are required to manage it? What is the duration of the pain when it occurs? (seconds vs. minutes vs. hours) Has it now become a spontaneous or constant event?

Provocation/relief: What stimulates the pain? (chewing, cold drinks, posture) What relieves it, if anything?

Of the four entities, the intensity/duration category has the most profound impact on the preliminary diagnosis. Seltzer and Bender stated that a history of spontaneous pain (pulpitis) is pathognomonic of irreversible pulpal damage, remedied only by complete extirpation. These teeth often present with concomitant thermal sensitivity, especially to cold. Thus, when stimulated, the patient experiences an uncomfortable sensation lingering more than a few seconds, even after the cold is removed. In the latter stages of pulpal demise, the patient can experience throbbing that persists minutes or hours after cold stimulation. If the refractory component of the nerve has been compromised, it cannot reset itself after stimulation; hence, it keeps firing and the response lingers.

The patient's recollection of the first occurrence of the discomfort can be vague, but questions targeted to the chief complaint (provocation) could prove insightful. For example, did their sensitivity to cold begin shortly after their last visit? A review of the record may reveal that you observed a "blush" in the dentinal surface of the suspected tooth that was prepared for a crown during that appointment. The patient considered the mild postoperative discomfort "normal" for that particular procedure, and the occasional twinges part of the "healing" process. It was not until some months after the final cementation visit that the twinges became more frequent, punctuated by bouts of thermal sensitivity. Left unattended, this pulpitis, and the associated neural barrage, can precipitate a phenomenon termed central sensitization, a reduced threshold of excitability in secondary, or projection, neurons. Nerve fibers from other teeth can share this second-order tract with fibers from the chronically irritated tooth; this is termed convergence. Consequently, these unaffected teeth can themselves become "sensitized" to peripheral stimulation. This mechanism is the foundation for referred pain, where stimulation of one site produces a painful response in a different location, usually another tooth. This scenario warrants precise clinical testing, where the locus of stimulation (provocation) and the locus of perception (localization) are dramatically contradictory to what the patient perceives and reports. Thorough testing and meticulous attention to detail in these instances will enhance the probabilities of making an accurate diagnosis, and the appropriate treatment can be rendered.

One final thought about testing: Deciding which test to use or weight can be unclear, so adhere to the principle that has always served me well: mimic the symptoms. If the patient reports that it hurts when he or she drinks something cold, then begin your triage by testing individual teeth with a cold pellet. This will quickly ascertain which tooth is suspect and narrow the focus of your clinical investigation. That finding, coupled with other corroborating results, will assure your arrival at the appropriate diagnosis and minimize your dental "pulp-lexion."

Stephen P. Niemczyk, DMD, is the past director of the undergraduate and graduate endodontic programs at the University of Pennsylvania. He is currently the director of endodontic microsurgery at Harvard University and Albert Einstein Medical Center. He is the founder of Endodontic Microsurgical Innovations, and is in full-time practice in Drexel Hill, Pa. He can be reached at [email protected].