In order to evaluate the significance of seven Class III indicators (molar relation, cranial deflection, ramus position, porion location, Xi to Pt Vertical, Xi to SNa Vertical and Xi-S-Na angle) seventy cases with a Class III malocclusion and excessive facial depth were selected from the files of the Loma Linda University Orthodontic Department, Loma Linda University Oral Surgery Department and Fundacion Jimenez Diaz Hospital Orthodontic Department (Madrid, Spain), and compared to a control group of seventy non-Class III cases.
Means and standard deviations of all variables were calculated and compared between the sample and control groups. Significant differences were determined with Independent t-tests. Interrelationships between Class III indicators were analyzed with simple correlation coefficients. A discriminant analysis was performed to determine which association of variables was most significant for the Class III and control populations. A multiple regression test was used to determine the most consistent skeletal Class III indicator.
The results showed: 1). an anterior porion location and forward ramus position were evident in skeletal Class III cases, 2). a forward location of the mandible (Xi point) in relation to the cranial base was observed in the sample group, 3). cranial deflection was similar in the sample and control groups, 4). anatomical analysis of these para meters would suggest an increased flexure of the posterior cranial base, 5). the association of molar relation, ramus position and porion location correctly classified 92.14% of the total population, 6). observation of simple correlation coefficients between the seven Class III indicators demonstrated a high correlation of the proposed new variables (Xi to Pt vertical, Xi to SNa vertical and Xi-S-Na angle) with ramus position, 7). multiple regression tests indicated that ramus position was the most consistent indicator of Class III malocclusion.
Michael J. Fillman
David R. Rynearson
James R. Wise
Master of Science (MS)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Orthodontics; Orthodontics, Preventive; Surgery, Oral; Mandible; Malocclusion
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This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Canut, Javier, "A Statistical Evaluation of Class III Indicators in a Caucasian Population" (1989). Loma Linda University Electronic Theses, Dissertations & Projects. 1233.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives