Reliability of Soft Tissue Cephalometric Parameters Using Conventional and Digital Cephalometric Radiogram

Tamar Kublashvili, Katerin Kula, Robert Craven, 
Zurab Vadachkoria

The purpose of this study was to compare the intra-rater reliability of measurements of soft tissue cephalometric landmarks between storage phosphor digital cephalometric images and conventional cephalometric images using hand tracing and computerized cephalometric programs. Four angular and eleven linear (total of 15) cephalometric measurements were hand traced and digitized in two software programs (Dolphin 7.0 [D], Vistadent 8.0 [V]). A conventional film and a digital image were obtained simultaneously with single exposure (hybrid cassette technique). The conventional cephalogram was scanned; the phosphor plate was processed by laser scanner (Gendex). Scanned and storage phosphor images were saved to a Zip disc as JPG files. Two lateral cephalograms (one conventional and one digital) of the same patient were used. Every landmark was hand traced and digitized ten times on ten separate days. Holdaway's and Steiner's soft tissue analysis were performed. All measurements were made by a single investigator. To assess the reliability of the different techniques, coefficient of variation (CV) were computed for all measures, by imaging technique. Statistically significant differences among the groups were tested using Multivariate ANOVA with repeated measures accepting p<0.05 as significant. Although there were significant differences between various measurements, results showed no consistent difference between three techniques (Hand Tracing [HT], Vistadent Scanned [VS], Vistadent Digital [VD], Dolphin Scanned [DS] and Dolphin Digital [DD]).

Keywords:  orthodontics, cephalometrics, soft tissue, storage phosphor screen, digital radiography