Recording devices of the type mentioned above are known in the dental field. Their recording plates have to be fixed on the natural or prosthetic teeth of the patient to ensure that they do not slip and that the tongue does not push them aside. After the recording plates have each been secured on the upper jaw and lower jaw, respectively, of the patient (for example with rapidly setting dental silicone), the patient is asked to bite, i.e. to press the jaws together, and also the recording plates fitted on them, whereupon the stylus is pressed onto the opposite writing surface. The patient is then asked to make certain movements of the lower jaw relative to the upper jaw, whereupon the stylus draws a tracing on the writing surface, for example by leaving a scratch mark in a wax layer applied to the writing surface. From this tracing, or so-called “arrow point”, a skilled person, for example a dentist, is able to derive information concerning the position of the patient's jaws in relation to one another, for example for production of a removable or permanent dental prosthesis or for monitoring the occlusion of the existing teeth of the patient.
In the recording device, the stylus can be arranged on the upper recording plate or on the lower recording plate, both arrangements having their advantages and disadvantages. If the stylus is arranged on the upper recording plate, the tracing is more easily and more conveniently visible to the skilled person, even though the wrong way round, and thus easier to view, but consequently more difficult to interpret. In the converse scenario, the tracing is less easily and less conveniently visible, but the right way round, and thus more difficult to view but easier to interpret.
To be able to be used correctly in dentistry, the recording device, when placed in the patient's mouth, must force the pressed-together jaws of the patient forwardly (in specialist terminology “anteriorly”) at the center by not more than about a centimeter and must prevent the normal bite position (in specialist terminology “occlusion”) from being reached. A main reason for this is that, in the case of fairly wide opening, the nature of the jaw joint not only effects a pure rotation (in which the jaw compass opens) but also an undesired sagittal movement (in which the lower jaw moves forward). Therefore, there is not much available height for the construction of the recording device, and for this reason the previously known recording devices, except for newly produced total prostheses, are cumbersome and their recording plates are difficult to secure on the jaws of the patient. In other words, working with them involves considerable effort and time. In the prior art, there are no recording plates available that can be used for all dental situations or at least for the majority of them. In the case of dentulous patients in particular, the skilled person has to spend more time in producing upper and lower plastic plates, because the recording plates have to be integrated into a plastic base adapted exactly to the teeth. The corresponding time spent doing this increases the cost to the patient (and if appropriate to the health insurance companies).
U.S. Pat. No. 2,481,203 discloses a device for recording the position of two mastication surfaces in relation to one another. The recording plates appear to be configured in such a way that they can be guided on the dentition; in reality, however, no guiding is guaranteed in the vertical direction. This is because the recording plates have a dish-shaped base so that no space is lost in the vertical direction and so that the supporting pin has vertical space therein. There is admittedly also a lateral abutment on the dentition as soon as suitable compounds (for example of silicone) are placed between the recording plates and the teeth. By contrast, however, vertical support is obtained only on the mucosa, not on the dentition.
This device and other known devices do not permit reliable recording of dentulous patients without preliminary work being carried out, for example individual production of suitable plastic parts. In the case of dentulous patients, reliable recording without the need for preliminary work is as yet an unsolved problem.