*Read before the Mid-West Component, Edward H. Angle Society, January, 1971, Scottsdale, Arizona. From the Departments of Plastic and Maxillo-facial Surgery and Dentistry, The Children's Memorial Hospital, Chicago.

Read at the January, 1971 meeting of the Midwestern Component of the Angle Society.

From the Departments of Orthodontics, Pedodontics and Anatomy, Dental faculty, University of Oslo, Oslo, Norway.

This investigation was supported by Grant HD-00157-09 from the Institute of Child Health land Human Development, National Institutes of Health.

Taken in part from a thesis in partial fulfillment of the requirements for the degree of Master of Science, Loma Linda University, School of Dentistry.

From a thesis in partial fulfillment of the requirements for the degree of Master of Science, Tufts University School of Dental Medicine.

From the Department of Oral Medicine, University of Alabama, Birmingham, Alabama.

Given at the January, 1971 meeting of the Midwestern Component of the Angle Society.

From the Orthodontic Department, Northwestern University Dental School. Read before The Edward H. Angle Society of Orthodontists, Scottsdale, Arizona, January, 1971. Supported by grant number D02224-06. U.S.P.H.S.