Student Theses, Dissertations and Capstones

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Thesis - NSU Access Only

Degree Name

Master of Science (M.S.) in Dentistry

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College of Dental Medicine

Publication Date / Copyright Date



Nova Southeastern University


A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

Objectives: The purpose of this study was to evaluate clinical outcomes based on the American Board of Orthodontics Objective Grading System (ABO-OGS) in a 30-month postgraduate orthodontic residency and to determine what factors affected these treatment outcomes. Methods: Consecutively debonded cases from July 1, 2010 to June 30, 2011 treated by residents in the Orthodontics Department at Nova Southeastern University were graded using the ABO-OGS. The age and sex of the patient, the treatment time, the missed appointments and the number of providers were documented. Discrepancy indices were calculated for each patient. These variables were assessed and their associations with the obtained treatment outcome scores were evaluated. Results: The average OGS score of the debonded cases was 33.87. There was no significant correlation between total OGS score and the demographic or explanatory variables. There were significant correlations found between the discrepancy index (DI) and the treatment time, the number of providers, but not the OGS. Significant correlations were also identified between treatment time and the number of failed appointments and the number of providers. Extraction cases were shown to have a significantly longer treatment time. Out of the eight objective measurements of the OGS, occlusal contacts, marginal ridges, buccolingual inclination and alignment/rotations scored the highest points in our evaluation with an average of 7.81, 6.37, 5.04, and 5.01 respectively. Conclusions: This study indicated the Nova Southeastern University Orthodontic Department average OGS score is about 6 points higher than the ABO clinical exam passing score. The initial complexity of a case was not a pre-determined factor for the final treatment results. This study identified several aspects of treatment outcomes that need improvement including, occlusal contacts, marginal ridges, correcting buccolingual inclination and improving the alignment.


Dentistry | Orthodontics and Orthodontology


Health and environmental sciences, Discrepancy index, Objective Grading System, Orthodontics, Outcomes assessment, Treatment outcomes



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