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A methodological study of errors in vertical measurements of edentulous ridge height on orthopantomographic radiograms
Author(s) -
RAMSTAD TORE,
HENSTENPETTERSEN ODD,
MOHN ERIK,
IBRAHIM SAMIRA I.
Publication year - 1978
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/j.1365-2842.1978.tb01259.x
Subject(s) - maxilla , variance (accounting) , ridge , analysis of variance , variance components , mathematics , mandible (arthropod mouthpart) , statistics , orthodontics , dentistry , medicine , geography , biology , cartography , botany , accounting , business , genus
Summary The purpose of this methodological investigation was to study the relative magnitude of the various errors in vertical ridge measurements from orthopantomograms of edentulous patients. The study was divided into two parts, Part I and Part II. Part I included eleven patients. Two standard orthopantomograms were taken of each patient. Part II included five of the eleven patients in Part I. Here, a third X‐ray taken with the mouth open was added to the X‐rays from Part I. The X‐rays were traced by three dentists. Twelve vertical measurements in the maxilla and in the mandible were made. The variance produced by the patients (morphological variance) and those produced by the dentist, the X‐ray, the interaction patient‐dentist, the interaction dentist‐X‐ray and the random variance (methodological variances) were separately estimated on the basis of a three‐way mixed analysis of variance model. In Part I, on the average, the sum of the methodological variances constituted 1·7 % and 2·5 % of the total variance in the maxilla and in the mandible respectively. The X‐ray produced the greatest single variance component, averaging 1·1 % in both jaws. Although generally statistically significant, the remaining methodological variances were of low magnitude. The interaction patient‐dentist, however, was not significant in most cases. In Part II, on the average, the sum of the methodological variances increased to 38·8 % in the maxilla and 4·6 % in the mandible, mainly caused by an increase in the variance produced by the X‐ray.