Transversal Microradiography main

Transverse Microradiography

TMR or contact-microradiography is the most practical and widely accepted method used to assess de- and re-mineralization in dental hard tissues in in-situ and in-vitro studies. It is a highly sensitive method to measure the morphology of and the change in mineral content of enamel and dentine samples.

TMR Method

In TMR the tooth sample to be investigated is cut into thin slices (about 80 µm and 200 µm for dentine samples). The sections are cut planoparallel and are oriented perpendicularly to the atomical tooth surface. A microradiographic image is made on high resolution film by X-ray exposure (CuKalpha) of the sections together with a calibration stepwedge. The microradiogram is digitized by a video camera or photomultiplier. The mineral can be automatically calculated from the gray levels of the images of section and stepwedge. Parameters of interest are mineral loss (Delta Z in Vol%.µm), lesion depth (Lesd in µm ), ratio or average loss of mineral content in the lesion area (Delta Z / Lesd in Vol%), the mineral vol% and position of the subsurface layer and lesion body.

Inspektor TMR for Windows

This commercially available system includes an X-ray generator with a specially designed X-ray camera, a microscope with CCD-camera-detector and stabilized power supply, a connection to a PC and dedicated software: ‘TMR for Windows’ (click screendump on the right), and a complete course how to perform TMR to achieve the highest accuracy and reproducibility of the TMR measuring parameters.

Inspektor TMR for Windows specifications

The accuracy of TMR for enamel and dentine in lesion depth is about 200 Vol%.µm in DeltaZ. With TMR mineral details of approximately 2-3 µm can be detected. The time required for making 5 scans plus evaluation is 3-4 minutes (which is less than 1 minute for a scan!). The time required for acquiring stepwedge data is one minute or less depending on the number of stepwedge steps. Statistical analysis of many scans is supported. You can group scans according to measurement results in blind studies. You can export all data to your favorite Windows spreadsheet and word processor and of course printouts can be made of all data, images and graphs on all printers supported by Windows. Extensive reports about the TMR method, its possibilities and applications have been published by Ten Bosch and Angmar-Månsson (1991) and by Arends and Ten Bosch (1992).

More information

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References

Arends J, Ten Bosch JJ: Demineralization and remineralization evaluation techniques. J Dent Res 71:924-928 (1992)
Angmar B, Carlström D, Glas JE: Studies on the ultrastructure of dental enamel. IV The mineralization of normal human enamel. J Ultrastructure Res 8:12-33 (1963)
De Josselin De Jong E, Ten Bosch JJ, Noordmans J: Optimized microcomputer-guided quantitative microradiography on dental mineralized tissue slices. Phys Med Biol 32:887-899 (1987)
Ten Bosch JJ, Angmar-Månsson B: A review of quantitative methods for studies of mineral content of intra-oral incipient caries lesions. J Dent Res 70:2-14 (1991)