Photocephalometry: Errors of projection and landmark location

Ceib Phillips, Jim Greer, Peter Vig, Steve Matteson

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

A method called photocephalometry was recently described for the possible soft-tissue evaluation of orthognathic surgery patients by the superimposition of coordinated cephalographs and photographs. A grid analysis was performed to determine the accuracy of the superimposition method. In addition, the reliability of landmark identification was analyzed by the method error of Baumrind and Frantz, using three replicates of twelve patients' photographs. Comparison of twenty-one grid intervals showed that the magnification of the photographic image for any given grid plane is not correlated to that of the radiographic image. Accurate comparisons between soft- and hard-tissue anatomy by simply superimposing the images are not feasible because of the difference in the enlargement factors between the photographs and x-ray films. As was noted by Baumrind and Frantz, a wide range exists in the variability of estimating the location of landmarks. Sixty-six percent of the lateral photographic landmarks and 57% of the frontal landmarks had absolute mean errors for all twelve patients that were less than or equal to 2.0 mm. In general, the envelope of error for most landmarks was not circular. Although the photocephalometric apparatus as described by Hohl and colleagues does not yield the desired quantitative correlation between hard and soft tissues, valuable quantitative information on soft tissue can be easily obtained with the standardization and replication possible with the camera setup and enlarged photographs.

Original languageEnglish (US)
Pages (from-to)233-243
Number of pages11
JournalAmerican Journal of Orthodontics
Volume86
Issue number3
DOIs
StatePublished - Sep 1984

Keywords

  • Soft tissue
  • photocephalometry

ASJC Scopus subject areas

  • Dentistry(all)

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