Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Rose Dissertation 3.5.2023.pdf (2.86 MB)

ETD Abstract Container

Abstract Header

FUNCTIONAL MORPHOLOGY OF THE TRABECULAE OF THE PRIMATE MANDIBULAR CONDYLE

Rose, Nicole D
http://rave.ohiolink.edu/etdc/view?acc_num=kent1678020953996817

Abstract Details

2023, PHD, Kent State University, College of Arts and Sciences / School of Biomedical Sciences.
External jaw morphology has been linked to diet and feeding behavior in primates, where biomechanical significance of condylar trabeculae is still being evaluated. Thus, the structural variation of condylar trabeculae remains largely unknown. I investigate trabecular architecture of the mandibular condyle to assess size-related variation, relationship to feeding behavior, and deterioration secondary to edentulism. I used µCT images of mandibular condyles of adult strepsirrhine primates, adult and neonatal callitrichid primates, and of elderly edentulous and dentate humans. For the non-human primates, the entire trabecular volume was processed using Avizo 8.0 to remove cortical bone. For the human samples, cubed sections were used and compared to cubed sections from the twelfth thoracic vertebra and the distal radius. VOIs were imported into BoneJ for measurement of trabecular parameters. When appropriate, phylogenetic comparative methods were used to address issues of phylogenetic non-independence. Similar to nonhuman primate postcranial bones, the mandibular condyle of strepsirrhine primates exhibits negatively allometric scaling with no alterations in the two features which should most affect load resistance: bone volume fraction and degree of anisotropy. This suggests primate trabecular architecture appears to have generalized scaling trends and trabeculae do not appear to undergo size-related increases in load resistance abilities. This study is the first evidence that the trabeculae of the mandibular condyle scale similarly to those of the postcranium. I compared ontogeny of condylar trabeculae of the tree-gouging common marmoset (Callithrix jacchus) and the non-gouging cotton-top tamarin (Saguineus oedipus). Several growth trends suggest the marmoset does not have a superior load resistance ability than its nongouging relative: bone volume fraction decreased in the marmoset while increasing in the tamarin; spacing increased and connectivity decreased in both but much more markedly in the marmoset. This study supports previous studies suggesting marmosets are not adapted for generating and resisting especially large bite forces during gouging. These results provide the first ontogenetic study of the trabeculae of the primate mandibular condyle. Tooth loss decreases occlusal contacts and thereby presumably reduces loading of the mandibular condyle during chewing. Contrary to previous studies, I found no evidence of changed morphology of the condylar trabeculae in edentulous individuals. Because osteoporosis contributes to tooth loss, I assessed correlations with bone mineral density and found no correlation of trabecular morphology with decreased bone mineral density. Evidence of decreased loading may yet be found in other structures but were not seen in the trabeculae of the condyle. This is the first study taking bone mineral density into account when assessing condylar trabeculae following edentulism. These results are the first demonstrating that trabecular bone in the head scales similarly to that of the primate postcranial skeleton and provide the first ontogenetic study of the trabeculae of the primate mandibular condyle. My results provide corroborative evidence that marmosets are not adapted for generating relatively large bite forces during gouging. They also challenge the current thought that condylar trabeculae regularly deteriorate in the absence of loading. More work is needed to understand how the trabeculae of the primate mandibular condyle are affected by feeding strategies and changes in jaw loading.
Christopher Vinyard, PhD (Committee Co-Chair)
Susan Williams, PhD (Committee Member)
Linda Spurlock, PhD (Committee Member)
Jesse Young, PhD (Committee Member)
Tobin Hieronymus, PhD (Committee Co-Chair)
Rebecca German, PhD (Committee Co-Chair)
240 p.
Anatomy and Physiology; Biomechanics; Physical Anthropology
mandible; condyle; trabeculae; primate; human; edentulism; scaling; ontogeny

Recommended Citations

Citations

  • Rose, N. D. (2023). FUNCTIONAL MORPHOLOGY OF THE TRABECULAE OF THE PRIMATE MANDIBULAR CONDYLE [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1678020953996817

    APA Style (7th edition)

  • Rose, Nicole. FUNCTIONAL MORPHOLOGY OF THE TRABECULAE OF THE PRIMATE MANDIBULAR CONDYLE . 2023. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1678020953996817.

    MLA Style (8th edition)

  • Rose, Nicole. "FUNCTIONAL MORPHOLOGY OF THE TRABECULAE OF THE PRIMATE MANDIBULAR CONDYLE ." Doctoral dissertation, Kent State University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=kent1678020953996817

    Chicago Manual of Style (17th edition)

kent1678020953996817
42
© 2023, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.