principle of internal attachment was 1st formulated by
kennedy
applegate
herman chayes
bechet


answer: herman chayes


reference:


Intracoronal Retainers is also known as internal attachments for Removable Partial Denture. The principle of internal attachment was first formulated by Dr. Herman E.S Chayes in 1906.

In the placement of intracoronal retainers, the surveyor is used as follows:
1. To select a path of placement in relation to the long axes of the abutment teeth that will avoid areas of interference elsewhere in the arch.
2. To cut recesses in the stone teeth on the diagnostc cast for estimating the proximity of the recess to the pulp (used in conjunction with roentgenographic information to estimate pulp size and location) and to facilitate the fabrication of metal or resin jigs to guide the preparation of the recesses in the mouth.
3. To carve recesses in wax patterns, to place internal attcahment trays in wax patterns or to cut recesses in castings with the handpiece holder.
4. To place the keyway portion of the attachment in the casting before investing and soldering; each keyway must be located parallel to the other keyways elsewhere in the arch.