Search

In order to complement the neurophysiological-neuropsychological curriculum of the medical and dental medicine training at the RWTH Aachen a practical course in pain psychophysiology was installed using contemporary means. In consideration of the most frequent symptom presented by patients, students’ self-experience when studying pain and the related psychophysical adaptation processes appeared direly needed. This required the development of a non-invasive system to induce a circumscribed pain. The development and scientific testing of such a system was the objective of this dissertation. Toothache as a phenomenon is widely known and seemed well suited as a pain paradigm using which the emotional as well as the physical reactions triggered by the pain event should become describable. According to own considerations and earlier studies a pain sensation should be possible by fast cooling of the upper middle incisior, comparable to what is also applied in dentistry as a sensibility test. The number of methods suited for these needs was limited by the fact that the cold applied had to be substantial as well as it had to be localized in order to be able to harvest precise usable results. These criteria were ideally met by so-called Peltier elements, heat pumps, which are widely used in a great many different technical areas. Due to their technical specifications, however, they needed adaptation to the particular demands of an application in humans. Hence, next to a mount a special cooling system was crafted from a copper block which was perfused by cold water. The mount for the fastening of the Peltier element at the tooth was built from a simple, flexible and individually adaptable track which ended extraorally pressed to the tooth with the help of an orthodontic headgear. This also allowed for an individual adaptation to different jaw forms and sizes and could also compensate for slight dental rotations. Control of the performance of the Peltier element was understandably tightly coupled to its cooling. Both were coordinated and controlled using an electronic equipment especially devised for the required purposes. The stimulator was experimentally tested in vitro using isolated horse teeth. This showed that the temperature inside the teeth declined on average by -10° C after cooling for 60 s. This therefore proved the efficiency of the stimulator objectively. In first experiments on voluntary test subjects, it was shown that this performance sufficed to trigger a subjective pain reaction.