Visualization of the human periodontium using serial thin section contact radiography.

A method is described to produce radiographs of thin sections of human teeth and periodontal structures. These high resolution contact x-rays allow for visualization of the microscopic details of the mineralized components of these tissues in a dimension heretofore not examined. Twenty-five blocks of human jaws containing teeth affected by periodontal disease were obtained from cadavers. Sagittal, transverse and cross-sectional serial slices were cut using a rotary instrument (1500 rpm) with a water-cooled 3-inch jewelers slot saw. Five hundred-micron sections were made of jaw specimens containing 2 or 3 teeth. The radiographs were taken with a Faxitron low voltage x-ray machine on Kodak-Ortho, Type 3 film. Films were exposed at a distance of 12 inches from the x-ray source at 35 kVp and 1.0 mA for 3 minutes with the specimen in direct contact with the film. Spatial representation of the internal structure of the alveolar bone was obtained using this technique and the detailed anatomy of the vascular channels within the cancellous and cortical compartments of the jaws was studied. Mineralization patterns of plaque and calculus, calcifications in the periodontal ligament, pulp calcifications, accessory root canals, caries and detailed structural changes in the enamel and cementum were also viewed on these films with the aid of microscopy. Magnifications of up to 30 times were used without excessive image distortion resulting from film grain.