A sample of twenty-three activator treated patients, in the growth years up to age eighteen were evaluated at three time intervals, before treatment, end of treatment, and five years post-treatment. The average time period of the post-treatment evaluation period was 5.7 years after the end of active therapy. The patients' ages ranged from 8.4 to 13.3 years at the beginning of activator treatment.

In the correction of the Class II malocclusion, no other form of orthopedic mechanics were utilized in this sample. In some cases full banding was used to align and level the arches prior to the activator therapy.

The beginning lateral cephalometric radiographs (T1 records) with predicted growth were compared to the finished treatment (T2 records) in order to discover the orthopedic and orthodontic effects of the treatment. Posttreatment cephalometric radiographs (T3records) were evaluated on all patients in order to determine the long term stability and effects of the treatment.

Comparisons of the end of treatment and posttreatment records were evaluated with the growth forecast records to determine the effects of the activator treatment. The eleven factor Ricketts' Analysis of each case was statistically analyzed to determine the significance of the treatment.

The data indicated a significant increase in mandibular growth with activator treatment in brachyfacial patients over that predicted in normal growth. The major increase in growth was in the vertical dimension, primarily in the condyle and ramus area, with no adverse rotation of the mandible.

The data suggest that activator therapy did not have any significant inhibiting effect on the growth of the maxilla.

The growth of the mandible increased more than expected during the active treatment period and continued to grow at the rate expected during the post-treatment period. The comparison of the end of treatment to the post-treatment records indicated that there was virtually no relapse of the molar relationship in the treated cases.

LLU Discipline





Graduate School

First Advisor

James R. Wise

Second Advisor

J. Milford Anholm

Third Advisor

Gary G. Morikone

Fourth Advisor

Karl K. Nishimura

Fifth Advisor

Robert J. Schulof

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Orthodontic Appliances, Removable



Page Count

vi; 44

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