What Is the Purpose of Pulp Vitality Tests?
Pulp vitality represents the integrity of the vascular supply to the tooth structures or the dentition. The pulp dentin complex includes the tooth root canals richly innervated by sensory fibers, predominantly the A-delta and C fibers. Therefore, most of the vitality tests used in everyday dental practice comprise primarily thermal tests and electric tests dependent on the stimulation of these A-delta and C nerve fibers.
Pulp vitality tests attempt to detect or help examine the presence of pulpal blood flow. Recent research makes it more reliable and apt to name pulp sensitivity tests than pulp vitality tests. However, even inspired by technical advances in this field, most of these tests fail to assess the blood supply to the tooth. Dental pulp testing is hence a handy and essential diagnostic aid in endodontics.
Pulp sensitivity tests primarily determine the tooth pulp's vitality response, especially with an active infection. When there is an active infection, the need for a root canal or extraction is decided after pulp vitality tests. The tooth is non-vital when there is a lack of any pulpal response. These tests include thermal and electric tests that infer the pulpal health from typical sensory stimuli.
Why Determine Pulp Sensitivity or Vitality?
Pulp sensibility tests though the most commonly used in clinical practice, are not without limitations nor challenges. The greatest diagnostic challenge in clinical practice is, of course, the correct assessment of pulp status. This assessment is complicated in pediatric dentistry. The practitioner encounters a developing dentition, traumatized tooth, a developing permanent tooth bud, or young children who cannot recall the exact pain history for the tooth in question.
The advantages or indications of pulp sensitivity tests are:
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Diagnostic purposes.
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The replication of pain symptoms or clinically triggering pain.
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To localize the source of dental or specific tooth pain.
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As an aid in excluding other causes like nonodontogenic or orofacial pain other than dental causative.
In cases where the pulp is infectious, the patient complains of acute or sudden pain aggravated by any thermal trigger. Pulp testing agents help identify or assess pulp health based on the qualitative sensory response of the primary offending tooth in question. They can be done before endodontic or orthodontic treatment for clarification over a suspect tooth. Furthermore, it is helpful in the follow-up or specific monitoring of the pulp in case of traumatized teeth.
Therefore, a patient's medical and dental histories are continuously evaluated by the dentist or the endodontist, apart from asking about the exact history of tooth pain before starting a pulp testing procedure.
What Are the Recent Advances Or Tests of Importance?
Modern advancements like laser Doppler flowmetry and pulse oximetry are commonly used in vitality assessment tests. According to recent research and modern dental literature, laser Doppler flowmetry appears to be the most accurate method in clinical practice. Pulp vitality tests also proved to be the only pulp sensibility tests for early and precise examination of pulpal health, especially in traumatized teeth. In addition, the pulp sensibility and vitality tests provide valuable diagnostic information when accurate results are interpreted. For example, an electric pulp test is combined with either CO2 snow or endo-ice to detect tooth vitality.
1. Cold and Heat Tests:
They can be performed on the suspected tooth by spraying ethyl chloride or ice. First, the tooth is isolated and dried by cotton rolls, and then the ice is sprayed on the small cotton pellets. These are placed on the incisal surface of the tooth. On the other hand, the heat test is performed by gutta-percha sticks. After proper isolation, the heated sticks will be placed on the incisal surface of the suspect tooth for testing. Radiographs of each tooth can also be taken and analyzed by the endodontist for any degenerative or resorptive changes in the pulp. Also, if there is any thickening of the periodontal ligament or any periapical changes, it may indicate an active pulpal infection.
2. Pulse Oximetry:
This is one of the most reliable non-invasive diagnostic devices that primarily depends on measuring and assessing the oxygen saturation levels in arterial blood. The device used for this method consists of a probe and has two light-emitting diodes; one diode transmits red light while the other transmits infrared light. The relationship between the pulsatile changes in the absorption of red light and infrared light is then determined accurately by the pulse oximeter device to measure the oxygen saturation levels of arterial blood.
3. Electric Pulp Testing (EPT):
In this technique, the electrical stimuli cause a change in ionic potential across the neural membrane. Then an induction of action potential occurs at the nodes of Ranvier in myelinated nerves. Finally, the pathway for the electric current is stimulated from the probe tip of the test device to the suspected tooth. This current reaches the dentinal tubules and enamel prisms, and the pulp tissue should activate a response if the tooth is vital.
4. Laser Doppler Flowmetry:
With the advent of this advanced modality, the primary application is determining the vitality of pulp in traumatized teeth or when the decay has been extensive. Other applications of this technique are mainly reported in pediatric dentistry. It helps to accurately aid in the differential diagnosis of nonodontogenic periapical origin infections and assess pulp blood flow effectively. The objective measurement of the "true" vitality of the pulp is by laser detection of the pulp blood flow rather than just testing the sensory functions of the suspected tooth.
What Are the Limitations of Vitality Tests?
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Clinical symptoms or radiographic modalities like IOPA (intraoral periapical radiograph), OPG (orthopantomogram), and CBCT (cone beam computed tomography) may still be required to determine the pulpal status.
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False-positive and false-negative responses in traumatized or necrotic teeth hamper the test reliability.
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In addition, in patients with psychotic disorders, substance abusers, or individuals under the drugs or chronic alcoholics, the degree of inflammation of the pulp or the state of vascularity tends to be altered; hence it is not a reliable test for such cases.
Conclusion:
Even with its limitations, pulp sensibility testing remains the most helpful indicator and aids in detection and diagnosis in current-day endodontic practice. With mixed success rates, attempts to clinically measure the accurate pulp blood flow are under research. However, recent studies show that with the advent of laser doppler flowmetry and pulse oximetry, the pulp sensitivity tests help in the accurate diagnosis of tooth vitality.
