Pulpal pathology
Knowledge about normal pulp and its pathology are important to arrive at a proper diagnosis. This section of question and answers covers the pulp and its various manifestations that can clear the doubts in making the diagnosis.
1. What is hyperemia?
Hyperemia is a reversible clinical condition characterized by the onset of a sudden, sharp pain in response to a cold stimulus which resolves immediately once the stimulus is removed. It is not a disease but just a symptom.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 142
2. What is Brannstorms hydrodynamic theory?
According to Brannstorm, the back and forth movements of fluids within the tubules stretch and stimulate the A- delta nerve fibres. If the movement occurs rapidly, the dislocation of the contents of the dentinal tubules can produce deformation of the nerve fibres of the pulp or predentin or even damage then cells and produce pain.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 143
3. How does a tooth with normal pulp respond to heat test?
Application of heat on a tooth with normal pulp makes the patient to experience a brief sensation of heat or a slight discomfort which disappears within a few seconds after the heat source is moved away from the tooth.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
4. What are the criteria to be confirmed before attempting to cap the pulp that is exposed during cavity preparation?
• There should be no signs and symptoms of irreversible pulpitis. • The tooth must not be sensitive to heat or cold or do not have any spontaneous pain. • There should be no pain on palpation or percussion • No periapical radiographic changes • No narrowing of pulp chamber or root canal • No calcification in the pulp chamber • No bacterial infection.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 154
5. Why MTA is considered to be ideal cement in endodontics?
MTA has all characteristics to seal the pathways of communication between the pulp and the oral cavity and between the root canal system and the periodontium. So it is considered as an ideal cement in endodontic therapy.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 155
6. What is the composition of MTA?
MTA is a powder that consists of five trioxides and other hydrophilic particles, which set in the presence of moisture. Hydration of the powder results in the formation of colloidal gel with a PH of 12.5 that solidifies to a hard solid structure.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 155
7. How does the hydrophilic character of MTA distinguish it from the other materials?
The materials that are used to repair perforations, to seal retro preparations in surgical endodontics, to close open apices or to protect pulp in direct pulp capping, are unavoidably in contact with blood and other oral fluids. MTA is the only material that is not affected by moisture or blood contamination in terms of its sealing ability and it sets only in the presence of water.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 155
8. What are pulp calcifications?
They are normal findings within the pulp whose etiology is unknown and observed radiographically. Their size varies from microscopic pulpoliths to concretions that occupy the entire pulp chamber. They are usually seen in teeth with a long history of chronic irritation such as dental, caries or deep restorations.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 141,142
9. How does pain occur in a tooth with hyperemic pulp?
The pain never occur spontaneously ,it is always provoked by a stimulus such as cold beverages or cold air, sugar, in response to curettage or root scaling or after a periodontal procedure that exposes the root surface. The pain subsides immediately after the stimulus is removed.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 142,143
10. Why does pain occur when the tooth is exposed to a brief air blast?
When the dentin is exposed to a brief air blast, the fluid within the dentinal tubules evaporates to a depth of 0.1 to 0.3mm and this leads to aspiration of odontoblasts and nerve fibres within the tubule. The stretched or disrupted nerve fibres produce pain.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 143
11. How does a cold stimulus produce pain?
The cold stimulus causes the fluids within the tubules to contract, causing the fluids to flow in a centrifugal direction owing to the pressure within the pulp. This flow causes the nerve fibres to stretch within the tubules, together with the odontoblasts.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 143
12. Why is hyperemic pain difficult to be localized?
The pain is of pulpal origin and the pulp lacks proprioceptive nerve endings. So the diseased tooth cannot be localized sometimes, not even the arch, upper or lower. Only the side right/ left can be said since the pain does not cross the midline.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 143
13. How is the diseased tooth identified by clinical tests?
If the patient says that the pain is due to cold stimulus, the application of cold is the best method for identification. The least suspected tooth is tested first by touching the cervical areas of the teeth with an ice stick and finally the diseased tooth. This is to familiarize the patient about the test performed. The dentinal response is quicker in the cervical area since the enamel thickness is less there and it is a poor heat conductor.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 143
14. What are the clinical findings in a tooth with hyperemic pulp?
Spontaneous pain in response to a stimulus that disappears when the stimulus is removed, normal response to percussion and palpation, no mobility and no radiographic changes.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 144
15. What is the duration of pain produced in pulpitis?
Pain produced by heat peaks with some latency, remains at this level even after the stimulus has been removed and takes several minutes to hours before resolving completely.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 144
16. How is pain produced in pulpitis?
The inflammation produced within the pulp tissues initially causes an exudation with a consequent increase of the intrapulpal pressure beyond the pain threshold and thus produces spontaneous pain.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 144
17. Why is there frequent nocturnal pain in pulpitis?
The pain occurs spontaneously when the patient assumes a supine position or when the patient lies down because in this position, there is an increase in the intracranial pressure producing pain.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 144
18. How is the tooth localized in diagnosing the diseased tooth in pulpitis?
Localization is difficult in pulpitis also since the pulp lacks the proprioceptive nerve endings. Since the pain is produced by a hot stimulus, heat application in a sequential manner from the last suspect tooth will be helpful in identifying the diseased tooth. The diagnosis is based on the reproduction of symptoms only.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 144
19. How does a heat stimulus produce pain in pulpitis?
The heat stimulus when applied to the tooth causes dilatation of blood vessels, tissues and gaseous products of proteolysis and increase the pain.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
20. How does cold relieve the pain in pulpitis?
A cold stimulus, on application to the painful tooth, has a contractile effect on the remaining functional vascular bed, reducing the intrapulpal pressure below the pain threshold of the pain receptors still present.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
21. How is heat applied in diagnosing the diseased tooth?
Heat is applied to the individual tooth with a hot ball of GP, attached to the end of a small spatula or any other instrument. The cervical area of the tooth is touched, beginning with the last suspected tooth.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
22. How do the existing fillings respond to thermal tests?
Existing metallic fillings absorb and retain the heat and cause exaggerated responses to thermal tests even if the pulp is normal. Synthetic fillings do not transmit heat and may give false negative response. So thermal testing on the fillings should be avoided.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
23. What is the characteristic response of a tooth with pulpitis to thermal tests?
When thermal test is performed on a tooth with pulpitis, the pain increases after a slight latency period, even after the stimulus is removed. The pain persists for a variable length of time till it is interrupted by cold or anesthesia.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
24. Why is electric pulp testing not very useful in diagnosing pulpitis?
A positive response to electric pulp test indicates that the pulp is vital but provides no information about the health of the pulp. So it is not very helpful.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
25. How do radiographs aid in diagnosing a tooth with pulpitis?
Radiographic examination may show the presence of interproximal caries that are not clinically seen and caries under old restorations, close to a pulp horn. Periapical zone is usually intact while sometimes a slight widening of the PDL may be seen.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
26. How is pulpitis identified histopathologically?
The diseases of the pulp always proceed in a corono apical direction. There is a small abscess collection in the horn. Around the microabscess, there can be an area of necrosis, then an area of infiltrate of polymorpho nuclear leukocytes and a hyperemic area with many dilated and bulging vessels filled with blood. More corono apically, there is proliferation of fibroblasts and beyond this is the normal intact pulp tissue.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 147,148
27. How is pulpitis with periodontal involvement easily diagnosed?
Pulpitis with periodontal involvement is easily diagnosed since the tooth can be localized by the patient, which is sensitive to pressure and to percussion due to involvement of the proprioceptive nerves in the periodontal ligament.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 150
28. How does pulp necrosis occur following trauma to a tooth?
After trauma, there is damage to the vascular peduncle. The inflammation causes the pulp tissue to disintegrate continuously forming a slowly enlarging zone of liquefaction necrosis. The lack of collateral circulation aggravates and accelerates the process that leads to total necrosis of the tissue.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 150
29. What does the zone of necrosis contain?
The zone of necrosis contains irritants that arise from both tissue destruction and aerobic and anaerobic bacteria. These irritants come into contact with the adjacent vital tissue and continue to cause damage in apical direction.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 150
30. How does necrotic pulp present radiographically?
The radiographic findings are normal. A slight widening of the periodontal ligament space may be present.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 153
31. How does MTA react with water?
MTA sets in the presence of water only. Hydration of the powder results in the formation of a colloidal gel with a PH of 12.5 that solidifies to a hard solid structure in approximately 3-4 hrs.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 155
32. How is MTA said to be biocompatible?
When MTA was used for direct pulp capping, it resulted in the formation of dentin bridges and demonstrated absence of cytotoxicity when came in contact with fibroblasts and osteoblasts. So it is said to be biocompatible.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 155
33. What properties of MTA stimulate dentin bridge formation?
Dentinogenesis of MTA can be due to its sealing ability, biocompatibility and alkalinity.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 156
34. How is MTA compared with calcium hydroxide as a pulp capping agent?
Similar to calcium hydroxide, MTA also initially causes necrosis by coagulation in contact with pulp connective tissue. But the bacteria tight seal provided by MTA makes it more superior.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 156
35. How is pulp capping performed with MTA?
The exposed pulp is irrigated with Naocl to control bleeding. The MTA powder is mixed with sterile water and the mixture is placed at the exposure site and compressed with a moist cotton pellet. Then another moist cotton pellet is placed and the rest of the cavity is filled temporarily. After 4 hrs, when the material is set, the cotton pellet and the temporary material are removed and the tooth restored. Regular re call checkups done.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 156
36. How does the presence of calcifications in the pulp affect direct pulp capping?
The pulpal calcifications which are normal radiographic findings within the pulp steal space from the cellular component of the pulp and in some way interfere with the vascularisation of the surrounding tissue. Only if the pulp has an ample blood supply, it will have considerable reparative capacity. So if there are calcifications, direct pulp capping may be affected.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 137,142
37. Why does a probe or excavator passed over the dentin produce pain?
The pain is associated with dentinal hypersensitivity explained by the hydrodynamic theory which states that the back and forth movement of fluids within the dentinal tubules stretch and stimulate the nerve fibres and produce pain.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 143
38. What does persistent pain in a hyperemic tooth indicate?
Inspite of treating the hyperemic tooth, if the pain persists, the cause was not a simple hypersensitivity or hyperemia. The presence of irreversible inflammation is suspected.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 144
39. What does a history of painful tooth with insomnia indicate?
A history of a patient with painful tooth and insomnia indicates that the pulp of the tooth is necrotic and lying down leads to an increase in the intra cranial pressure producing pain and insomnia.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 144
40. Why does heat application always begin with the least suspected tooth?
Beginning with the least suspected tooth makes the patient learn the response of a normal pulp and tolerate the response of an inflamed pulp thereby reducing the anxiety and fear.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
41. What is the inference when a tooth does not respond to the heat test?
Lack of response to the heat test in a tooth indicates that the pulp of the tooth is necrotic or the tooth has been endodontically treated.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
42. When a tooth with pulpitis does become sensitive to percussion?
Only in the most advanced cases when the inflammation or infection extends to the periodontal ligament, the tooth becomes sensitive to percussion.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 145
43. How does an open or closed pulp chamber affect the progression of liquefactive necrosis?
Drainage of the inflammatory exudates influences the progression of the liquefactive necrosis. Pulpitis in a tooth with completely closed pulp chamber leads to a total necrosis of the pulp more rapidly. Whereas, in a tooth with open pulp chamber, there will be a slow destruction with degeneration of the coronal pulp and presence of vital tissue at the radicular level.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 150
44. What are the clinical conditions in which MTA is used as the ideal material?
Repair of perorations, sealing retro preparation in surgical endodontics, closing open apices and to protect the pulp in direct pulp capping, MTA is considered to be ideal since all these conditions are inevitably in contact with blood and other tissue fluids. MTA is a material that is not affected by moisture or blood and sets only in the presence of water.
Ref: Endodontics,Arnaldo Castelluci,IL Tridente, vol 1; 155