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Johnston, Fayth (2012) MANDIBULAR SHAPE IN MYOSTATIN-DEFICIENT MICE: A GEOMETRIC MORPHOMETRIC ANALYSIS. Master's Thesis, University of Pittsburgh. (Unpublished)

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The relationship between muscle function and mandibular morphology is unclear. Manipulating the size or function of muscle and then observing the effect on adjacent bone is one way to explore this relationship. The premise is that muscles under function create stress and strain on bone, thereby altering bone morphology. Myostatin knockout (MKO) mice are hypermuscular and may be used as an animal model to study this muscle-bone association. Previous studies comparing MKO mice have used conventional cephalometric analyses to compare their skeletal morphology to wild-type controls. The objective of our study is to provide a phenotypic description of the mandible in MKO mice compared to wild-type CD-1 control mice by quantifying their shape variation at 28 days of age utilizing a geometric morphometric approach. The hypothesis proposes that epigenetic muscle-bone interactions during development cause mandibular shape changes in MKO mice compared to the wild-type controls by 28 days of age. The present sample included nine wild-type and eight MKO mice 28 days old. Eleven mandibular landmarks were recorded on each cephalogram. The landmarks were aligned using Procrustes superimposition method and new coordinates were created to perform a canonical variates analysis (CVA). Results found a significant difference in the mean mandibular shape between the MKO and wild-type groups (Procrustes statistic: 0.047; p = 0.014). The inferior border of the mandible of the myostatin-deficient mice showed increased curvature and decreased ramal height when compared to the wild-type mice. The curved mandible phenotype here may be analogous to the ‘rocker’ mandible reported to be prominent in the Polynesian population. These findings suggest that changing muscular forces altered mandibular morphology most dramatically in regions associated with masticatory muscle attachments.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Johnston, Faythfsb4@pitt.eduFSB4
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee MemberMooney, Mark Pmpm4@pitt.eduMPM4
Committee MemberNeiswanger, Katherineknacct@pitt.eduKNACCT
Committee ChairWeinberg, Seth Msmwst46@pitt.eduSMWST46
Thesis AdvisorWeinberg, Seth Msmwst46@pitt.eduSMWST46
Date: 9 July 2012
Date Type: Publication
Defense Date: 3 May 2012
Approval Date: 9 July 2012
Submission Date: 16 May 2012
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 53
Institution: University of Pittsburgh
Schools and Programs: School of Dental Medicine > Dental Science
Degree: MDS - Master of Dental Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: Myostatin-deficient mice, Geometric morphometrics, Orthodontics
Date Deposited: 09 Jul 2012 15:49
Last Modified: 15 Nov 2016 13:58


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