The purpose of this research was to determine the frictional resistance of four self-ligating brackets and two conventional bracket systems using two different types of orthodontic arch wires in both wet and dry fields. Six different brands of upper right central incisor brackets with 0.018-in slots were evaluated. Group A : self-ligating bracket: Opal (Ultradent), Damon 2 (Ormco), Time (American Orthodontics), In-Ovation (GAC). Group B: conventional-ligating: Virage (American Orthodontics), and Mini-Twin (Unitek) served as the control brackets. Two different orthodontic wires of varying alloys and sections were tested: 0.016-in round stainless steel (Ormco) and 0.016x0.022 inch rectangular nickel-titanium (American Orthodontics).

To simulate second order bends into account, the brackets were set at either 0°, 5°, 10°, 20° degrees to the wires. Each wire-bracket combination sample was evaluated in a wet and dry field. To test the samples in a wet field, the wires were sprayed with distilled water just before testing. Each bracket was bonded in such a manner as to remove the tip and angulation from the system and then set in a special attachment built for this study, which was then placed on the base of the universal testing machine MTS BIONIX 2000 (Figure 1). A wire ligated to the bracket was attached to the crosshead of the machine and pulled at a speed of 10 mm/min for a distance of 50 mm. Each bracket was tested only once and each wire specimen was drawn through one bracket only to eliminate the influence of wear. A total of 288 bracket-arch wire samples were studied (Table 3).

A four stage partially nested test was used to analyze the data. Significant differences were found in the frictional forces among the different groups. The Opal bracket from the self-ligating group showed the lowest frictional force and In-Ovation from the same group showed the highest frictional force. The Virage bracket from the conventional ligating group showed higher frictional forces than the Mini-Twin bracket from the same group.

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


Graduate School

First Advisor

Craig Andreiko

Second Advisor

Joseph M. Caruso

Third Advisor

Roland D. W. Neufeld

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Orthodontic Appliances; Orthodontic Brackets; Ceramics; Metals



Page Count

ix; 41

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