Movements of healthy and periodontally involved teeth measured with laser reflection technique

Dental holography--earlier investigations and prospective possibilities

Optical measuring techniques- such as holography, contouring, moire, and speckle- offer new nondestructive possibilities for bridging the gap between in vitro and in vivo measurements in dentistry, and thus increase the possibility of achieving more accurate and sometimes more objective diagnosis and therapy. This presentation is an attempt to illuminate the future prospects of holography and speckle in the dental field by giving a survey of the past in combination with a vision of the future. Holographic determination of implant properties and polymer testing are discussed to show that different prosthodontic constructions and different dental materials can be tested to obtain information about their deformational behavior. Conditions such as loading, temperature, and moisture are no obstacle, and functional tests can be carried out on realistic objects with complex shapes and various thicknesses as well as on test samples. This can be a great advantage in that it facilitates the laboratory testing of samples of real size and shape under the same conditions as those in clinical testing. Although the oral environment gives rise to a very complex situation, including many parameters with unknown relations and magnitudes, optical methods sometimes provide a picture of the total course of events. Furthermore, clinical time can be saved this way by a reduction of the time needed for treatment of the patient. The future is exciting, but it requires further developments using different optical methods. This is not an utopia; interdisciplinary collaborations and communications between the technical and dental fields are imperative.