Diagnostic Pulp Tests
Cold, heat, and low-voltage electric current are used clinically as diagnostic tests of the pulpal-periapical disease. These tests aim to assess the physiological function of the sensory nerve fibers rather than the vitality of the pulp. The vitality of the pulp is determined by the physiological function of blood supply. Pulp tests are also used to reproduce symptoms, which the patient is or was experiencing.
The dental pulp is innervated by A- and C-type sensory nerve fibers [5, 6]. A-8 and A-p fibers are located around the odontoblast layer and C fibers in the pulp proper. A-8 fibers have a low-threshold for activation. When stimulated, a sharp and stabbing pain is induced and lasts few seconds and is related to dentin sensibility . C fibers have a high-threshold for activation. When stimulated, a dull and lingering pain is induced and may last several minutes . C fiber activation is considered related to pulpal inflammation. The physiological function of A-p fibers is not well defined.
Cold test most frequently used is Endo-Ice (tetra-fluoroethane). It has temperature of about -26.2 °C (Figs. 3.1 and 3.2). Other cold tests include CO2 snow and
Fig. 3.1 Performing the cold test, EPT, and heat test
Fig. 3.2 Devices or material used for pulp tests
ethyl chloride. Heated gutta-percha is employed as heat test and its temperature varies (Figs. 3.1 and 3.2). The pluggers of System B unit can also be used as heat test (Fig. 3.2). The temperature of System B can be set at desirable temperature. For electric pulp test (EPT), the electric pulp tester is used (Figs. 3.1 and 3.2).