Four sets of patient models were selected from the eighty cases Ormco Corporation used in the development of their lingual bonded appliance. These four sets of models were duplicated and identical sets of four models were sent to each practitioner and the laboratory. The practitioners and the laboratory were to position the lingual brackets on the models from second bicuspid to second bicuspid upper and lower and return them to Loma Linda University Department of Orthodontics for evaluation.

The laboratory chosen for placement of the brackets was the Ormco laboratory in Glendora, California. The laboratory ran these four cases through in their normal fashion to simulate clinical conditions. The practitioners were divided into two groups for evaluation, experienced and inexperienced.

Three experienced lingual practitioners were chosen from the Ormco Corporation Lingual Task Force and four inexperienced lingual practitioners were chosen from the faculty and alumni of Loma Linda University.

The four sets of models from the laboratory and the seven practitioners were sectioned per tooth and photographed with the use of a custom jig and a 35mm camera with a macro lense. The film was processed in slide format and measurements were made using method modified from that described by Dr. Andrews of "A" Company. The data was submitted to the Department of Biostatistics of Loma Linda University for computer analysis. The measured crown torque was compared to the torque prescription of the Ormco lingual bonded appliance. It was found that there were no significant statistical differences in any of the placements. Although, the calculation of the mean absolute torque difference did allow us to rank the laboratory and the practitioners. The ranking showed an experienced practitioner first, an inexperienced practitioner second, and the laboratory third.

LLU Discipline





Graduate School

First Advisor

Lawrence W. Will

Second Advisor

Norman S. Carter

Third Advisor

Earl R. Crane

Fourth Advisor

Arthur J. Morgan

Fifth Advisor

Gray G. Morikone

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Orthodontic Appliances; Crowns; Prosthodontics



Page Count

vi; 26

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