[The interproximal periodontal pocket and its measurement].

Periodontal probing is the most important examination to determine the presence and severity of periodontal lesions. In the interproximal contact areas, probing depth is not accurate because there are some errors in angulating the probe. The purpose of this study was to establish the correct probing method in these areas. Therefore a new interproximal periodontal probe was developed. It eliminated the errors which arise from angulating a probe. The effectiveness of the 8-point method which uses both a conventional probe and the new type interproximal one was determined. The results were as follows: 1. 20 human dry skulls were selected to indicate the necessary angle at which a probe could reach the center of the interproximal contact area. Approximately 30 degrees was needed in molars. This was the most popular angle for measurement in these places. 2. 12 periodontal patients were selected to determine the errors in probing depth between a conventional probe and the new type interproximal one when a probe angulated 30 degrees. The average error was 0.56 mm, indicating that the new type interproximal probe must be used when a probe was angulates 30 degrees. 3. 19 periodontal patients who received a flap operation were selected to determine the effective probing method which could predict the alveolar bone defects in the interproximal contact areas. Measurement of 3 points (bucco-mesial or distal line-angle, linguo-mesial or distal line-angle and center of mesial or distal) could estimate the form of interproximal bone defects. 4. 45 periodontal patients were selected to determine the condition of interproximal periodontal pockets. Marked periodontal damage was present not only at the center of interproximal contact areas but also in the other sites. These results suggest that the new interproximal periodontal probe is a reasonable instrument for angled probing in the interproximal contact areas, and the 8-point method is the most effective one to reveal the periodontal condition in detail.