A quantitative analysis of the forces and pressures generated within the root canal system during vertical condensation of warm gutta-percha

Date
1974
DOI
Authors
Cohen, Jeffrey Robert
Version
OA Version
Citation
Abstract
A technique was devised for measuring the intracanal forces and pressures generated during the warm gutta percha packing procedure. Foil type strain gauges were applied to Schilder root canal pluggers, and these pluggers were then calibrated for applied vertical forces. Subsequently, several recently extracted single canaled teeth were made ready for obturation with warm gutta percha through careful cleaning and shaping. Strain gauges, also of the foil type, were then attached to the external root surface of these teeth and calibrated for applied internal root canal pressures. These teeth were then obturated with the warm gutta percha technique while simultaneous measurements of the forces and pressures developed within the root canal system were recorded. Finally, the gutta percha was removed and pressure was applied to the root canal system in an attempt to cause root fracture. In a subsequent experiment, single canaled extracted teeth, which had been preserved in saline for various unknown time periods (ranging from 24 hours to one year) were selected at random. These teeth were then cleaned and shaped as if they were to be obturated with warm gutta percha. Each tooth was then mounted on a hydraulic pressure producing apparatus and subjected to a maximum pressure of 2500 lbs./in[2] in an attempt to cause root fracture. A comparison of the pressures generated with the root canal pluggers to the pressures recorded at the gutta percha-dentinal wall interface showed the two to be of completely different magnitudes. The maximum pressure generated by the end of a root canal plugger was found to be 3O,357 lbs./in.[2] The corresponding maximum pressure recorded along any portion of the root canal wall was found to be only 2,333 lbs./in.[2] 0f all the teeth tested to pressures of 250O lbs./in.[2], not one showed any signs of fracture. Mean plugging forces were determined for individual teeth as well as for individual pluggers for both the packing down and packing back procedures. Although differences were found between pluggers and teeth, some significant and some not, the mean plugging force for all teeth combined was found to be identical for both the packing down and packing back procedures. This value was 4.2 lbs.
Description
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Thesis (M.Sc.D.)--Boston University, School of Graduate Dentistry (Endodontics) 1974.
Includes bibliography.
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.