Radiogrammetric Replicability and Direct Validity of Small Mandibular Measurements in the 45-Degree Projection

Abstract

Radiogrammetrics on 2 sets of radiographs, using an automatic printout GOAT and 1 set of direct caliper measurements on each of 26 skeletalized human mandibles showed inter-film replicability and inter-technique,, enlargement corrected, validity coefficients of 0.90 -0.91. A densitometric "trace" was made on each of 1 set of radiographs using a Joyce- Loebl recording densitometer to provide a 10X enlargement of the radiographic image, and showed equal or greater promise compared with GOAT measurements of the same film images. The magnitude of RMS [root mean square] measuring error was [plus or minus] 0.5mm. An enlarged densitometric trace introduces a new approach to microradiography, and when combined with automatic printout measuring device (GOAT) affords automated data collection of small measurements with minimal readout error.