Maxillary palatal expansion has long been used in orthodontics as a means of correcting constricted and collapsed dental arches. The quadhelix appliance, developed by Drs. Robert Ricketts and Ruel Bench, expands buccal segments and causes distobuccal rotation in upper first molars. The objective of this study was to assess the direct effects that the quadhelix appliance on the surrounding dentition and buccal bone in the maxillary premolar and molar areas in a finite, measurable manner. This assessment was made using the NewTom 3G. The pre-quadhelix and post-quadhelix NewTom 3G images of twenty patients treated in the Graduate Orthodontic Clinic at Loma Linda University School of Dentistry were compared. Specifically, the width of expansion, premolar and molar inclination, molar rotation, and the buccal bone levels were evaluated. A statistically significant amount of bone thickness loss was found on the buccal side of the premolar and molar regions while marginal bone level bone loss was found on the buccal side of the first molars. The amount of change in molar rotation was not found to be statistically significant. A considerable amount of buccal crown inclination was created in the first and second premolars while the amount of buccal crown inclination in the molars was not statistically significant at p<0.05.

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


Graduate Studies

First Advisor

Roland Neufeld

Second Advisor

Joseph Caruso

Third Advisor

Jay Kim

Fourth Advisor

David Rynearson

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Palatial Expansion Technique; Orthodontics, Corrective; Orthodontic Appliances; Molars; Bicuspid; Alveolar Bone Loss -- prevention and control



Page Count

x; 34

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