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2.75 Team Dental Head-rest


This class project was part of the MIT class 2.750, a senior level design class where groups of students try to come up with innovative solutions to real world problems posed to them by members of the medical community. There were many interesting challenges in my year - from making a automatic skin suturing device, to making a automated bed to help move obese patients - but our group was focused on trying to make a new head-rest for a dental chair that provided ease of adjustment and six degrees of freedom of adjustment.

This image shows the team at our final presentation with our sponsor from Japan testing out the device.

After a period of frantically designing several different prototypes and presenting the results to the group we chose the most 'out there' idea which was using the principles of jamming of granular media in order to produce the head-rest. Jamming of granular media essentially is the tendency of a granular (i.e. sand, ground coffee, etc) to become rigid under elevated pressures. The idea was to have a long beam made out of a flexible sleeve filled with a granular media that would allow a large range of motion while being continuously adjustable and quickly lockable using a vacuum system.

This shows a photo of our final prototype. The granular media shown in the picture is basically small melanin plastic pellets. These were found to have one of the better strength to weight ratios of the materials that we tested.

This shows a computer model of the whole system including its attachment to the dental chair. A device that allowed motion in several additional degrees of freedom, primarily sliding into and out of the chair in the "z" direction was also designed to use jamming of granular media to lock it into place.

Videos and 3D Models

This video demonstrates the computer model of the latest 2.75 dental headrest prototype.

This video shows one of the earlier concepts for providing six degree of motion for a dental chair - the use of a hexapod (or Stewart platform).

A 3d pdf of the hexapod, one of the earlier prototypes, that although it didn't get chosen as the final design still looks pretty cool.