Measurements of alveolar bone height at tooth and implant abutments on intraoral radiographs. A comparison of reproducibility of Eggen technique utilized with and without a bite impression.

A short review of various radiographic methods for quantitation of marginal bone changes is given. With the method suggested by Eggen (1973) alveolar bone heights on intraoral paralleling radiographs of tooth and implant abutments could be determined directly in "true' values. A calibrated measuring film (increments adjusted in accordance with the approximately constant magnification) was utilized with a magnifying (x 2) viewer. The reproducibility of this direct method was tested, with and without a bite impression, and found to be high. The use of an impression did not seem to have any significant influence on the reproducibility of the method when measuring bone heights at teeth. However, regarding bone height measurements at implants, the impression seemed to bring about a small but significant improvement. The main source of error seemed to be the recognition of the reference points in the alveolar bone. The discussion of available quantitation principles indicated that radiographic bone height should be evaluated in absolute values in clinical studies of comparative nature. The present method seems to be suitable for comparative, clinical examinations of alveolar bone height at teeth and implants.