1. Field of the Invention
This invention generally relates to dental appliances and, more particularly, to devices for measuring the sensitivity of teeth.
2. Description of the Prior Art
One of the most controversial testing methods in dentistry today is electric pulp testing. Many researchers have concluded that the validity of such pulp tests is debatable and that little or no correlation can be found between the pain-perception threshold and the histologic status of the pulp. In contrast, the American Dental Association Council for Materials and Devices stated in 1973 that electric pulp testers are a valid aid to dental diagnosis when handled and used correctly.
This controversy stems first from the subjective variability in human oral structure. For example, the enamel and dentin morpholgy, the surface conditions of the tooth, and the complex oral environment all can cause false and sometimes negative data. In addition, the mental and emotional state of the patient as well as the administration of drugs can influence the patient's response.
The second factor causing this controversy stems from the electrical and mechanical shortcomings of the electrical pulp testers that are commercially available today. Most of these pulp testers form an electrical circuit through the dentist and rely on the contact between the dentist's free hand and the patient. Such a circuit is subject to substantial variation in circuit resistence. Further, some researchers have found that there is no correlation between the dial settings and the output of some present pulp testers. None of the commercially available instruments today make quantitative measurements of the electrical energy applied to the tooth. The present day instruments all make relative measurements which cannot be correlated with other pulp testers. In addition, the relative measurements of these instruments have great operator induced variability and, thus, have little scientific value. Another problem with the prior art has been that the onset of pain was the threshold reference; but in fact the onset of pain is a condition of overstimulation.