Ritter Dental Intra-Oral Stereoscope

Rochester, New York, USA, 1930s

This mid-century intra-oral stereoscope from Ritter Dental was used to view dental x-rays in 3D. The switch at the base gives 5 levels of brightness to the lamp that sits behind the focusing screen. The concept of stereoscopic viewing in dentistry was introduced in 1898 by W.S. Hedley who published an article called “Radiostereoscopy.” This particular viewer was developed in the ‘30s and believed to have been used until at least the 1950s.

From Ritter Dental’s 1933 publication called “Instruction book embodying the use of the modern dental X-ray unit in intra-oral, stereoscopic, extra-oral, sinus profile and extremity radiography”:

“The plane radiograph gives but two dimensions, length and breadth. The third dimension is made possible by simultaneously viewing two films which have been exposed from slightly different angles representing the pupillary distance so that the fusion or blending of those two films in the Ritter Stereoscope produces upon the eye the impression of relief or depth, known as the third dimension.”

“The stereoscope is a bi-focal optical instrument equipped with decentered prism lenses that may be adjusted to the most critical eyes. With the aid of these adjustments and control of light the films are blended into one image, a procedure which is in reality a simple means to accomplish the registration of depth or third dimension.”