Determination of the facial/oral alveolar crest using RF-echograms. An in vitro study on the periodontium of pigs.

This study is a part of a research project in which we have been investigating the use of the ultrasonic pulse echo technique as a means of determining in vivo the facial/oral alveolar crest precisely and routinely. Here, RF-echograms are presented, showing the facial/oral periodontium of pigs. These echograms have been produced using a focussed 20 MHz transducer and a special design of an ultrasonic measuring and analysis system. In one series of measurements on macerated periodontia of pigs we found out that RF-echograms characteristic of a particular level of the facial/oral pericrestal aspect can be achieved. Based upon these results, we succeeded in determining exactly the height of the facial/oral alveolar crest in a 2nd experimental group using the intact periodontium of pigs. In all experiments, we tried to image separately both the echo amplitudes of the facial/oral alveolar plate and of the tooth surface. In other words, the periodontal ligament space is imaged sonographically. In our experience, the imaging of the space is an important aspect for the correct interpretation of echograms. Possibilities and limits of this method are demonstrated and explained.