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Biomedical subjects

D Lukas

Publications and source records attributed to D Lukas.

At least 19 recordsLinked to original sources
PubMed1992

High-speed filming of the Periotest measurement.

Periodontal disease may be diagnosed with the Periotest technique, which involves electronically controlled and reproducible percussion of tooth. The movement on percussion was investigated with high-speed film and then compared with the return of teeth after static deflection for several seconds as has been reported previously by Lukas and Scholz. The elastic and viscous properties of the periodontium and the surrounding bony tooth socket are to a large extent non-linear. The 10-20 microns deflection of the healthy tooth represents only a fraction of static tooth mobility published by Parfitt or Schulte et al. The visco-elastic properties of a healthy tooth enabling the percussion of the Periotest tapping head to be decelerated in less than 1 ms are largely lost in periodontitis. It is this essential difference which the Periotest method utilizes.

Alveolar Bone Loss↗
PubMed1992

Periotest for measuring periodontal characteristics--correlation with periodontal bone loss.

The Periotest measures the reaction of the periodontium to a defined percussive force. The percussion is applied to the tooth by an electronically controlled tapping head. Information on structural change is obtained by measurement of both the elastic and viscous characteristics of the periodontium. The latter prevent oscillations of the tooth in the alveolar bone. A value is calculated and is displayed as a "Periotest value". The following research report shows the relation of Periotest values to bone loss. Bone loss was quantitatively determined for 2312 teeth from orthopantomographic radiographs and for 900 teeth exposed to intra-oral films using the standard paralleling technique. A differentiation was made between vertical and horizontal bone loss. Clinical mobility index, pocket depth, gingival recession and papillary hemorrhagic index were also measured. There was a strong association between the Periotest value and bone loss. These results suggest that Periotest evaluation provides an objective indication of the extent of periodontal bone loss.

Adult↗
PubMed1992

The Periotest method.

The Periotest is a new instrument for the diagnosis of periodontal diseases. The 'Periotest value' depends to some extent on tooth mobility, but mainly on the damping characteristics of the periodontium. The Periotest measures the reaction to a reproducible impact applied to the tooth crown. The Periotest value is a biophysical parameter.

Electronics, Medical↗
PubMed1990

[Acoustic feedback for probing at constant force].

Probing of the gingival crevice is generally recognized as the most important diagnostic procedure in periodontitis. Reliable measurements are only possible by probing at constant force. A freshly isolated porcine mandible was used to test, if acoustic feedback enhances the reliability of probing. Our results indicate that the feedback significantly reduces the total probing force and also the variance between single measurements.

Feedback↗
PubMed1979

[Retrograde movement of upper incisors].

Labial stress of 1 to 8 n(102-815 Pond) was exerted on free-standing upper incisors, both healthy teeth and teeth damaged by progressive marginal periodontitis, until all creeping movement subsided and constant guidance was achieved. The teeth were then freed, and the resetting movements were measured without inertia and free of effect. The dampening characteristics of healthy and diseased teeth differed qualitatively in the first few milliseconds. Construction of a diagnostic device of determination of periodontal disease suitable for the general practice therefore ought to be possible.

Biomechanical Phenomena↗
PubMed1979

[The anatomical course of the mandibular canal--a computer assisted trigonometric radiographic interpretation].

The mandibular canal was demonstrated on two stereoscopic radiographs which correspond radiographically to isolated films of the mandible. The central ray forms 20 degrees and a 50 degrees angle with the camperian plane on the radiograph. A reference pointer attached to the teeth is also reproduced on the film. The angle and direction of the central ray is computed on the basis of the diagram of the reference pointer. A defined adjustment therefore is unnecessary when the radiograph is being taken. The coordinates of the mandibular canal and the surrounding root tips are accurately computed with a programmable computer.

Computers↗