Date of Award


Document Type


Degree Name

Master of Science (MS)




Almost two hundred years ago Hunter recognized the necessity of extracting teeth to ’’procure room for the others which are to be brought into the arch.” He further noted that, ”To extract an irregular tooth would answer but little purpose if no alteration could be made in the situation of the rest.”1

Extraction of selected teeth to gain room for the proper placement of the rest, and the subsequent procedures to utilize this space to the utmost advantage, have been integral parts of orthodontic treatment for many years.

Strang and Thompson2 stated that the ability to manipulate any orthodontic mechanisms successfully depends upon a complete understanding of the anchorage available in the structures that are to be modified.

Fogel and Magill3 observed that the proper utilization of the extraction space was such an important endeavor that the success or failure of treatment depended upon it. Because of the cardinal importance of space conservation, anchorage has become a dominant consideration in the treatment of most malocclusions.

The ever-present problem of establishing and preserving anchorage during treatment still remains to be solved in a manner that is satisfactory to all orthodontists.

Through the years, devices both intraoral and extraoral have been designed to preserve the stability of the teeth being used as anchorage. These devices were basically mechanical in nature.

In 1954 Begg4 introduced a technique based upon the use of light differential forces which did not appreciably disturb the anchor teeth. This technique applied physiologic principles in combination with clinically proven mechanics. The application of differential force is possible primarily because of the difference in root surface area of the various teeth; the greater the surface area, the greater the force required to initiate movement.

The purposes of this study were to conduct a more thorough investigation of actual root surface area of anterior teeth, and the posterior teeth used as anchorage, and to explore the possibilities of applying the information clinically in anchorage preservation.