Dr. med. dent. Christian Finke

In vitro abrasion using an air-powder polishing device and its quantification by radiotracer measurement
Dental Materials 15 (1999) 180-184
C. Finke et al

Objectives. This study was conducted to examine the assessment of abrasion of two different materials after neutron activation.

Methods. A fissure sealant material (Fissurit F/VOCO with a compressive strength of 235 MPa) and a glass ionomer cement (Aqua Ionofil/VOCO with a compressive strength of 170 MPa) were activated by irradiation with neutrons. Subsequent measurements of the full-energy-peak (FEP) (1368.55 keV of 24 Na) were made of the sample materials before and after abrasion via exposure to the air-powder polishing to accurately describe substance loss.

Results. Abrasion varied more than three-fold between the two materials.

Significance. Neutron activation and radiotracer measurement allows the quantification of abrasion effects in different materials. In comparison with other current methods its use may allow a superior measurement accuracy and precision in determining the abraded mass. q1999 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved.

Keywords: Abrasion; Wear resistance; Air-powder polishing; Fissure sealant material; Glass ionomer cement; Neutron activation; Radiotracer

Dr. med. dent. C. Finke / Publikationen
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Laser-Supported Dental Endoscope (LSDE) for the detection of early carious Lesions
Laser Physics, Vol. 13, No. 5, 2003, S. 773-780
R. Paul, J. Strauss, C. H. Finke, F. Fink

CONCLUSIONS
With the integration of a laser in an everyday dental endoscope, a diagnostic system was developed capable of recognizing cariously changed tooth enamel. This early stage is marked by the structural changes in the tooth enamel and appears as dark or bright regions of the enamel. Bright regions were the focus of this study, and we have assigned them as demineralized areas not infected with fluorophores. Microscope pictures proved the destruction of the areas which appeared bright in the laser beam. Measurements taken by using the widely employed caries detector „DIAGNOdent“ which has been optimized for detecting caries lesion in preceding stages, gave only „weak“ signals from the bright areas which could not be clearly diagnosed as a carious lesion. These results support our conjecture that the areas which appear bright in LSDE observations point to the early stages of enamel destruction.
At this stadium, we expect to have good chances of stabilizing the state of the enamel by fluoride-based therapy. In the in vitro experiments, we were able to prove that a dose of fluoride showed a continual reduction in the brightness of the defect enamel areas
throughout the course of treatment.
First observations with the LSDE on patients with bright lesions of tooth enamel showed a reduction in the brightness. With increasing remineralizing, the intensity of scattered light of the defect enamel is apparently permanently reduced, so that the area appears less bright. The LSDE can observe and record these changes throughout the whole therapy, thereby providing the possibility of controlling the course of therapy and its success. Further tests for a diagnostic application of the LSDE in a patient study are planned. The behavior of the autofluorescence of enamel when stimulated by uv-light impulses was demonstrated by the transition of caries to sound enamel. The conversion of the carious area to sound enamel was easily recognizable in the reduction of brightness.A comparative study between the results of the LSDE with 530-nm stimulation and a stimulation of 337 nm is being prepared.
We suppose that brightly appearing areas can be assigned to lesions corresponding to a preliminary stage of white spot lesions.

Dr. med. dent. C. Finke / Publikationen

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