Nah Nah Chen


Early cellular changes in pulps whose blood supplies were severed were studied using transmission electron microscopy (TEM). Twenty-eight extracted teeth were divided into seven equal groups. Except for the 0 hour group, all other teeth were incubated in Tyrode solution at 37°C, after extraction. After 1/4, 1/2, 1, 2, 4, and 8 hours, teeth were split open and the pulps were processed for light and transmission electron microscopy and evaluated for cellular changes. Except for nuclear pyknosis in the 4 and 8 hour groups, light microscopic examination revealed very little changes when compared with that of TEM examination. With the TEM, the first cells which showed changes were the odontoblasts and the most resistant structures to show changes were the unmyelinated axons. Changes observed in the nuclei included chromatin clumping, pyknosis and polarization of the nucleoli to the periphery. Cytoplasmic changes observed were mitochondrial swelling, dilatation of endoplasmic reticulum, increased vacuolization, and increased presence of lipofuscin and lipid inclusion bodies. Further, plasma membrane distortion, degeneration and fragmentation were also seen. Nuclear changes usually preceded cytoplasmic changes. Other observations were that endothelial cells showed a decrease in micropinocytosis and an increase in cytoplasmic protrusions. Nerve fibers exhibited degenerative changes in the myelin sheaths and a loss of microtubules in their axons. It was not possible to pinpoint in any of the cell types examined a specific time at which the transition from reversible to irreversible condition occurred.




Graduate School

First Advisor

Leif K. Bakland

Second Advisor

Robert Schultz

Third Advisor

James H. Simon

Fourth Advisor

Mahmoud Torabinejad

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Dental Pulp -- injuries; Dental Pulp -- blood supply; Microscopy, Electron



Page Count

x; 104

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website


Loma Linda University. Del E. Webb Memorial Library. University Archives