James Barra


Objective: Maxillomandibular tooth size ratio (TSR) is an important aspect in achieving a satisfactory orthodontic outcome. The purpose of this study is to compare TSR among orthodontically treated patients with different skeletal anteroposterior (AP) patterns. Methods and Materials: The post-treatment (T2) cone beam computed tomograms (CBCTs) of patients treated orthodontically without extraction and finished with canine and molar class I occlusion were evaluated. The subjects were categorized into class I, class II and class III skeletal pattern by analyzing A point-Nasion-B point (ANB) at T2. Overbite (OB), overjet (OJ), TSR for canine to canine (TSR3-3) and molar to molar (TSR6-6), maxillary incisor to sella-nasion (U1-SN) angle, sella-nasion to mandibular plane (SN-MP) angle, lower incisor to mandibular plane (L1-MP) angle and interincisal angle (IIA) were measured and recorded. The data were compared using Kruskal-Wallis one-way analysis of variance and correlated using Spearman rank-correlation coefficient at α = 0.05. Results: Of the 128 patients, 68 were skeletally class I, 29 were class II, and 31 were class III. The overall mean values for TSR3-3 and TSR6-6 were 77.0% and 92.4%, respectively. Significant differences (p < .05) were observed in all parameters when compared among different skeletal patterns except for both TSR values (p > .05). TSR3-3 and TSR6-6 were correlated with each other (ρ =0.485; p < .001) but bore no statistically significant relationship with any other parameter. Conclusion: The TSR values for dental class I non-extraction orthodontic cases are similar regardless of skeletal pattern and comparable to Bolton’s published values.

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


School of Dentistry

First Advisor

Rungcharassaeng, Kitichai

Second Advisor

Caruso, Joseph M.

Third Advisor

Rynearson, R. David

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Cone-beam Computed Tomography; Tooth Radiography; Mandible -- Growth & Development; Orthodontics; Corrective

Subject - Local

Tooth Size Ratio; Orthodontic Outcome; Skeletal Anteroposterior Patterns



Page Count


Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

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.


Loma Linda University Electronic Theses and Dissertations

Collection Website


Loma Linda University. Del E. Webb Memorial Library. University Archives