The purpose of this study was to determine changes that occur in the craniofacial complex, when a heavy interrupted orthopedic force is employed to retract the maxilla in the post puberal rhesus monkey. Cephalometric, histologic and anatomic examinations were utilized to substantiate the findings.

Four female rhesus monkeys were used for experimentation. Two were experimental animals and the other two controls. Cervical retraction with headgear was applied over a period of 313 days and 159 days to the two experimental animals. Forces not exceeding 2.5 lbs. were found most effective.

The findings were as follows:-

  1. A total posterior displacement of the maxillary base and dentoalveolar structures, producing a super Class III molar relationship and an anterior crossbite.
  2. An altered downward and backward movement of the craniofacial structures.
  3. An increase in the mandibular, palatal, occlusal plane angles and "Y" axis.
  4. A decrease in the facial plane angle.
  5. Osteoclastic activity observed in the zygomaticotemporal, zygomaticomaxillary, frontomaxillary, and frontozygomatic sutures, at the tuberosity and pterygoid plate region, at the insertion of the lateral pterygoid muscle into the neck of the condyle and on the superior surface of the condyle.
  6. Absence of inflammatory cells in the tissue specimens.
  7. A flattening in the region below the nasal openings.
  8. Sliding affect of the zygomaticotemporal sutures over one another.
  9. Coronoid processes moved down and back behind the zygomatic arches.
  10. A posterior crossbite tendency in the treated animals.
  11. The monkeys in the restraining chairs tolerating this part of the experiment very well.

The findings of this study clearly demonstrated changes in the craniofacial complex from cervical retraction forces applied to the maxilla.

LLU Discipline





Graduate School

First Advisor

Howard W. Conley

Second Advisor

Roland D. Walters

Third Advisor

Alden B. Chase

Fourth Advisor

Edwin M. Collins

Fifth Advisor

Elmer E. Kelln

Sixth Advisor

Charles E. Hunter

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings




Page Count

x; 92

Digital Format


Digital Publisher

Loma Linda University Libraries

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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

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