Files and links (1)
Free to read and download, Open Access
Thesis
Sexual dimorphism in symphyseal rigidity: a longitudinal study
University of Iowa
Master of Science (MS), University of Iowa
Spring 2013
DOI: 10.17077/etd.qzisz6s3
Abstract
<p>Objective: The purpose of this study to assess the relationship between masticatory function and symphyseal biomechanical properties using a longitudinal sample. Known differences in male and female maximum bite forces manifest during adolescence. If symphyseal bending rigidity is affected by function during ontongeny, we would expect variation in male and female growth allometries of certain biomechanical properties of the symphysis.</p>
<p><strong>Methods and Materials:</strong> Subjects were chosen from the Iowa Growth Study records for completeness and quality of radiographic images longitudinally. 19 females and 20 males were chosen. Lateral ceph images from 9 timepoints (age 3-20) were used to trace the external cortical outline of the symphysis. The biomechanical parameters (second moments of area (Ix, Iy, Imax, Imin)) were calculated from the external contours of the symphysis. Mandibular length was used as a proxy for overall mandibular size. All variables were scaled and growth allometries calculated by a reduced major axis regression. Clarke's T-test was used to test for significance. ANCOVA was used assess the interaction between symphyseal properties and sex, mandibular length, and sex+mandibular length.</p>
<p><strong>Results:</strong> No significant differences in symphyseal growth allometries of males and females were found (p>.05). No significant interactions between symphyseal properties and sex, and sex+mandibular length. (p>.05). A significant interaction between symphyseal properties and mandibular length was found (p<.05).</p>
<p><strong>Conclusions:</strong> Despite greater bite forces in males that manifest during adolescence, there were no differences in symphyseal growth allometries between males and females. Perhaps function does not play a significant role in development of symphyseal form. Perhaps the subtle effects of function on symphyseal morphology cannot be assessed by using only external cortical outlines for evaluation of symphyseal biomechanical parameters.</p>
Details
- Title: Subtitle
- Sexual dimorphism in symphyseal rigidity: a longitudinal study
- Creators
- Laura Lynn Bonner - University of Iowa
- Contributors
- Thomas E. Southard (Advisor)Robert Staley (Committee Member)Robert Franciscus (Committee Member)Steven Marshall (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Orthodontics
- Date degree season
- Spring 2013
- Publisher
- University of Iowa
- DOI
- 10.17077/etd.qzisz6s3
- Number of pages
- v, 45 pages
- Copyright
- Copyright 2013 Laura Lynn Bonner
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 41-45).
- Academic Unit
- Orthodontics
- Record Identifier
- 9983777172302771
Metrics
449 File views/ downloads
277 Record Views