Estimation of alveolar crest height using routine periapical dental radiographs.

The reproducibility of estimations of the alveolar crest height based on their relationship to two other fixed points on the tooth has been analyzed in a study of 302 routine periapical radiographs of 96 endodontically treated teeth. The radiographs were made at normal recall appointments by use of the extension tube paralleling technique. The various distances between four fixed points on each tooth in any radiographic series were compared by means of a statistical model. The results indicate that, in periodontal follow-up studies, completely standardized projection of the structures onto the film is unnecessary since measurements of the crest height can be related to any suitable fixed measuring standard on the tooth.