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Biomedical subjects

D Lukas

Publications and source records attributed to D Lukas.

At least 55 records · Page 3Linked to original sources
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↗
PubMedDate not supplied

Area-dependent enlargement ratios of panoramic tomography on orthograde patient positioning and its significance for implant dentistry.

The aim of this work was to study the behavior of vertical and horizontal enlargement ratios in panoramic tomography in various implant regions of the maxilla and the mandible. A method is presented that admits determination of regional enlargement ratios as a function of the implant region. Clearly defined characteristics of the implant body (Frialit-2 implants) are used as reference points. The vertical enlargement ratio varied between 1.21 and 1.29 on optimal orthograde adjusted tomographs, depending on the measured area. The horizontal enlargement ratio at the coronal end of the implant varied between 1.15 and 1.35. As it is below the vertical value in the lateral tooth area, this contributes to the distortion of the implant structures depicted. The horizontal enlargement at the apical end of the implant varies between 1.12 and 1.44. The difference in horizontal enlargement ratios also causes a distortion of the implant structures shown on the panoramic tomograph. Based on this study scenario, panoramic tomography may be well suited to preimplant diagnosis, particularly in the vertical dimension. With regard to transparent templates designed for implant placement, an enlargement of 1.3 in the perpendicular line and 1.35 in the horizontal line is proposed.

Aluminum Oxide↗
PubMedDate not supplied

Influence of the implant abutment on the Periotest value: an in vivo study.

OBJECTIVE: Periotest values for dental implants depend on the type of prosthetic abutment utilized for the restoration. If Periotest value cannot be measured at the single crown, the Periotest values used for comparison must be derived from the same type of superstructure. METHOD AND MATERIALS: Fifty-nine patients were selected from a regular follow-up program. At the end of the healing period, the Periotest values of Frialit-2 implants were measured at the gingiva former and abutment. The values were then compared with the Periotest measurements obtained at the placement of the final single crown and during the first follow-up examination. RESULTS: Compared to values measured at single crowns, the Periotest value measured at gingiva formers decreased on average by 3.5. The measurement of the abutment revealed a decrease of 1.7. Until the first recall and under functional loading of implants, the Periotest value increased on average by 1.8. These differences significantly differed from 0. CONCLUSION: If measurements at different abutments such as crown abutments or single crowns are necessary, comparison of the Periotest values in accordance with the given mean values will lead to more precise results. It is recommended that Periotest measurements be performed for the first and subsequent prostheses, during all prosthetic stages, to allow comparison if some parts of the prosthetic abutment have to be replaced.

Crowns↗