Differential Diagnosis (Reversible vs. Irreversible Pulpitis):
(1) Case history: The chief complaint & history of present illness provides valuable information in diagnosing the pulpal condition, even before performing the oral examination.
(2) “Pulp Sensibility” Tests:
They include thermal (cold, heat) and electric pulp tests (EPT). The term “pulp vitality” is a misnomer.
These tests reproduce the patient’s symptoms. The quantitative evaluation of the status of pulp tissue can only be determined histologically, as it has been shown that there is not necessarily a good correlation between the objective clinical signs and symptoms and the pulpal histology.
|Pulp Sensibility Tests||· They detect the responsiveness pulpal sensory nerve fibers.
· A positive response means that there are functional nerves in the pulp that respond to stimuli (even if the pulp is degenerating).
|· Heat test (heated gutta-percha, heated ball burnisher, hot water from syringe);
· Cold test: Ice stick, CO2 snow (dry ice), refrigerant spray (ethyl chloride or 1,1,1,2- tetrafluoro ethane on a cotton pellet), cold water in syringe;
· Electric Pulp Test (EPT).
|Pulp Vitality Tests||They detect the presence of blood flow in the pulp. Hence they are the true measure of pulp vitality.||· Laser Doppler Flowmetry (LDF);
· Pulse Oximetry.
|RESPONSE ON PULP SENSIBILITY TEST||INTERPRETATION|
|Sensation including pain that does not linger once stimulus is removed||· Reversible Pulpitis
· False (+)ve response
|Pain lingers even after removal of stimulus||· Irreversible Pulpitis
· False (+)ve response
|No response||· False (-)ve response
· Pulp Necrosis
False (+)ve result:
- Liquefactive necrosis of pulp;
- Nerves are highly resistant to inflammation, and may be responsive even after degeneration of the pulp.
False (-)ve result:
- Calcific metamorphosis [Pulp canal obliteration, receded pulp chamber due to secondary dentin deposition]
- Recent trauma;
- Immature tooth.
What does a “normal“ or “abnormal” response to Pulp test mean ?
- Baseline or normal response to either hot or cold is a patient’s report that a sensation is felt but disappears immediately on removal of thermal stimulus.
- Abnormal responses include lack of response to stimulus, lingering or intensification of a painful sensation after stimulus is removed, or an immediate, excruciatingly painful sensation as soon as the stimulus is placed on tooth.
(3) Clinical Intervention:
Diagnosing reversible versus irreversible inflammation is made by identifying the offending tooth, then removing the infected layer of carious dentin or the leaking restoration and totally sealing the lesion from the oral environment with a glass-ionomer or zinc oxide/ eugenol temporary restoration. If the inflammation is reversible the pain will cease almost immediately and, after a delay of at least three weeks to allow healing in the pulp, a definitive restoration can be placed.
Pulp Necrosis –
Complete loss of sensibility of dentin and pulp usually indicates that the entire pulpal tissue is dead. However there is not an absolute link between pulp sensibility (detection of viable nerves) and vitality (detection of blood supply), since patients may report apparently normal sensory responses in teeth which, on histological examination, show no evidence of vital pulp, while others have no sensibility in teeth which are otherwise normal.
Apical Periodontitis –
The periodontal ligament (PDL) at the root apex is also well innervated. Sensory nerves within PDL provide information to the brainstem nuclei on pressure or mechanical load and tooth displacement. Such sensory information subconsciously contributes to masticatory control and may also be noted consciously as touch, pressure and pain.
Inflammation in the periapical tissues decreases the critical firing threshold of the sensory nerves of the region and allows the initiation of pain by relatively minor tooth movement. Palpation through gentle movement of the tooth with finger pressure or alternatively percussion by gently tapping with a solid instrument may well elicit pain under these circumstances.
|Pulp Necrosis||· Absence of pain;
· May reveal previous history of pain;
· Pulp sensibility test: No response.
|Symptomatic Apical Periodontitis||· Tooth is tender on percussion;
· Radiograph may/ may not reveal widening of PDL space with loss of lamina dura;
· Associated with Irreversible pulpitis or Pulp necrosis.
|Asymptomatic Apical Periodontitis||· Tooth is NOT tender on percussion;
· Radiograph may reveals widening of PDL space with loss of lamina dura;
· Often associated with Pulp necrosis.
[From: Ingle’s Endodontics, 6th ed.; Cohens Pathways of the Pulp, 10th ed.]
DIAGNOSING PULPAL PAIN:
|PULPAL PAIN||PERIODONTAL PAIN|
|® Visceral pain;
® Responds to noxious stimuli with an inflammatory response.
|® Musculoskeletal pain;
® Related to masticatory function
- Search for source (carious tooth, fracture).
- Induce or increase the pain with “Provocative tests” à Pulp Sensibility tests.
- Arresting the pain à with nerve block local anesthesia à This arrests pain fully for the duration of the local anesthesia.
- Test cavity à it is the last resort, if all else fails.
- Wait & watch à for pain localization.
[From: Okeson. Bell’s Orofacial pains. ]
|Pain is said to be “referred” when the site of pain and source of pain do NOT coincide [site ≠ source].|
|The perceived pain occurs in a Vertical Laminated pattern à felt as RADIATING PAIN to head, in orbital/frontal, pre-auricular regions.|
|e.g.: Sinus toothache/headache à Tenderness of maxillary teeth (premolars, molars) and/or gingiva.|
|The phenomenon of referred pain is explained by the “Convergence theory”, where 2 peripheral afferent neurons from 2 different sites converge onto the same second order neuron in the trigeminal nucleus of spinal cord.|
[From: Cohen’s Pathways of the Pulp. 10th ed.]