The principle of (1) is to use a digital dental pulp vitality detector to detect the response of dental pulp nerve components to electrical stimulation through an electrical tester. Dental pulp vitality tester will interfere with the work of pacemaker, so it is forbidden for pacemaker patients to use it.

(2) Methods There are many kinds of root canal electrical instruments, and the operation steps are shown in the manual. The general operation steps are as follows:

1. Explain the purpose of the test to the patient before the test, so as to eliminate the patient's nervousness and obtain the patient's cooperation.

2. Wet and dry the test tooth, and apply a layer of toothpaste on the probe as a current conductor.

3. Put the probe on the neck 1/3 of the measured tooth lip or cheek to test.

4. Adjust the current scale knob and slowly increase clockwise from "0" until the patient responds. At the same time, remove the probe and record the reaction value.

5. Pay attention to the test, first measure the healthy control teeth, and then measure the affected teeth.

(3) Explain the electrical test results of pulp vitality.

1. The tested teeth are the same as the control teeth-indicating normal dental pulp.

2. The response value of the measured teeth is large-indicating that the pulp response is slow, and most of them are pulp degeneration.

3. The response value of the measured teeth is small-indicating that the pulp is sensitive.

4. The tested teeth are unresponsive-indicating that the pulp is necrotic.

(d) Factors influencing the interpretation of pulp vitality test results

1. Factors leading to false positive

(1) The probe or electrode contacts a large area of metal restoration or gum, and the current flows to the periodontal tissue.

(2) The tested teeth were not sufficiently wet or dry, and the current leaked to the periodontal tissue.

(3) Liquefied and necrotic pulp can conduct current to periapical tissue, which will react.

(4) Patients are highly nervous.

2. Factors leading to false negatives

(1) probe or electrode failed to contact enamel effectively.

(2) The patient has used sedatives, anesthetics or alcoholic beverages in advance. When the current is adjusted to the maximum scale, the affected teeth may

(3) The pulp of the newly erupted teeth with immature root tips did not respond to electrical stimulation.

(4) The over-calcified pulp in root canal often does not respond to current stimulation.

(5) Newly injured teeth may not respond to electrical stimulation.

3. Individual differences Individual differences between patients can also lead to different reactions in electrical tests. Therefore, in order to prevent the interference of individual differences, control teeth should be measured first, and then suspicious teeth should be measured to eliminate individual differences and obtain comparison standards.

It is generally believed that the pulp vitality tester is more reliable in judging whether the pulp is dead or alive. However, for each case, we should make a comprehensive analysis according to the medical history and clinical examination results, and exclude the above factors in order to make a correct diagnosis.

[Thinking]

1. Try to describe the electrical test method of pulp vitality.

2. Please describe the clinical significance of the results of pulp viability test.

3. What are the factors that affect the interpretation of pulp vitality electrical test results?