Recently, I received these two questions from the same reader. The answers have clinical application for all clinicians who practice endodontics. These questions underscore the importance of understanding the causes of pulpal inflammation as well as the basic indications for endodontic therapy with a diagnosis of irreversible pulpitis (IP).
The onset of an IP is correlated with, amongst many mechanical, traumatic, erosive, and microbial insults:
1) the depth of the fillings
2) the number of fillings
3) the type of filling material
4) how much water spray was used in preparation
5) the type of bur used
6) periodontal disease and lost attachment
and if:
7) the pulp was exposed and how the exposed pulp was treated
8) the tooth has coronal fractures
9) the dentin was acid etched
10) an impression has been taken
11) chemicals and adhesives were used to treat/bond the dentin
12) there is occlusal trauma
13) a crown has been cemented.
This list is by no means exhaustive. In short, the greater the number of additive factors over time that have contributed to the cumulative pulpal trauma, the greater the chance that the pulp may become irreversibly inflamed.
Symptoms of IP include:
1) pain that is spontaneous
2) pain that is lingering to hot or cold
3) severe pain to hot or cold that may or may not linger
4) pain to chewing (most especially accompanied by pain to hot or cold).
QUESTION 1
“I… need your help… Lingering pain is described as irreversible pulpitis. Is there any cutoff value in terms of time duration that differentiates between reversible and irreversible pulpitis, i.e. pain lingering for 10 seconds might be irreversible pulpitis whereas if it lingers for less, it’s reversible?”
QUESTION 2
“In addition to this, please respond to following related clinical scenario:
A male patient of 35 years presents with pain and sensitivity in his left maxillary first molar. The symptoms appear on taking cold only and remain for five minutes. The radiograph shows a deep carious lesion and no periapical pathology. Tooth is not tender to percussion. The patient is suffering from:
A- Reversible pulpitis
B- Irreversible pulpitis”
Answer to question 1
The short answer is no, there is not a “cutoff value.”
The more expanded and clinically relevant answer is that symptoms from irreversible pulpitis (IP) do not occur in a vacuum and virtually all such cases have signs, symptoms and clinical findings that are part of a larger set of findings spread over time. Very often, for example, patients who have lingering pain to hot or cold, irrespective of how long the lingering, tend to have had recent fillings or crowns on the offending tooth at some point in the past 6-12 months. Commonly, after the restoration, there is often ongoing pain of varying intensity almost immediately after the placement of the restoration.
Answer to question 2
Conclusively, this is an IP. The presence or absence of periapical pathology is not directly relevant to the diagnosis in this case. A patient with deep caries has had bacterial insult to the pulp. Sensitivity to cold for 5 minutes is a certain indication that the pulp is irreversibly damaged and will not recover. The fact that the tooth is not sensitive to percussion only tells us that the inflammation has yet to spread to the periapical tissues. It must be remembered that pulps die in a coronal to apical direction. In this clinical case, the pulp within the canal is irreversibly inflamed but without complete necrosis and apical symptoms. If the pulp were left, it would eventually die and toxic byproducts of this breakdown enter the apical tissues, cause inflammation, and eventual infection.
In the clinical case cited, it is somewhat unusual for a patient to only have a chief complaint of lingering sensitivity to hot or cold. Hot and cold sensitivity is usually accompanied by other symptoms, spontaneous pain and/or pain to chewing. It is possible for the patient or clinician to be lured into a false sense of security, if after spontaneous pain, the tooth becomes comfortable. In the patient’s mind, such comfort often means that they have healed.
If the symptoms of IP were to disappear without treatment, it is a virtual certainty that the pulp is becoming less vital or has lost vitality. In time, if left long enough, the patient will have some combination of the following: 1) obvious radiographic pathology 2) possible swelling, 3) pain (usually a deeper and more dull pain, unlike the sharper pain noted with an irreversible pulpitis).
It is my empirical observation that too often clinicians wait and delay treatment on teeth with obvious symptoms of IP. It is common, unproductive, and hopeful to wish that the pulp would heal in the presence of definitive IP symptoms. Unfortunately, in endodontic offices, often multiple times per day, patients present with IP who have been observed for some length of time. Often, there are symptoms of IP that are ignored either before,