Matthew C Coombs1, Xin She2, Truman R Brown3, Elizabeth H Slate4, Janice S Lee5, Hai Yao6. 1. Postdoctoral Fellow, Department of Bioengineering, Clemson University, Clemson, SC; and Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC. 2. Graduate Assistant, Department of Bioengineering, Clemson University, Clemson, SC. 3. Professor, Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC. 4. Professor, Department of Statistics, Florida State University, Tallahassee, FL. 5. Clinical Director, National Institutes of Health National Institute of Dental and Craniofacial Research, Bethesda, MD. 6. Professor, Department of Bioengineering, Clemson University, Clemson, SC; and Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC. Electronic address: haiyao@clemson.edu.
Abstract
PURPOSE: Approximately 2 to 4% of the US population have been estimated to seek treatment for temporomandibular symptoms, predominately women. The study purpose was to determine whether sex-specific differences in temporomandibular morphometry result from scaling with sex differences in skull size and shape or intrinsic sex-specific differences. MATERIALS AND METHODS: A total of 22 (11 male [aged 74.5 ± 9.1 years]; 11 female [aged 73.6 ± 12.8 years]) human cadaveric heads with no history of temporomandibular disc derangement underwent cone beam computed tomography and high-resolution magnetic resonance imaging scanning to determine 3-dimensional cephalometric parameters and temporomandibular morphometric outcomes. Regression models between morphometric outcomes and cephalometric parameters were developed, and intrinsic sex-specific differences in temporomandibular morphometry normalized by cephalometric parameters were determined. Subject-specific finite element (FE) models of the extreme male and extreme female conditions were developed to predict variations in articular disc stress-strain under the same joint loading. RESULTS: In some cases, sex differences in temporomandibular morphometric parameters could be explained by linear scaling with skull size and shape; however, scaling alone could not fully account for some differences between sexes, indicating intrinsic sex-specific differences. The intrinsic sex-specific differences in temporomandibular morphometry included an increased condylar medial length and mediolateral disc lengths in men and a longer anteroposterior disc length in women. Considering the extreme male and female temporomandibular morphometry observed in the present study, subject-specific FE models resulted in sex differences, with the extreme male joint having a broadly distributed stress field and peak stress of 5.28 MPa. The extreme female joint had a concentrated stress field and peak stress of 7.37 MPa. CONCLUSIONS: Intrinsic sex-specific differences independent of scaling with donor skull size were identified in temporomandibular morphometry. Understanding intrinsic sex-specific morphometric differences is critical to determining the temporomandibular biomechanics given the effect of anatomy on joint contact mechanics and stress-strain distributions and requires further study as one potential factor for the increased predisposition of women to temporomandibular disc derangement.
PURPOSE: Approximately 2 to 4% of the US population have been estimated to seek treatment for temporomandibular symptoms, predominately women. The study purpose was to determine whether sex-specific differences in temporomandibular morphometry result from scaling with sex differences in skull size and shape or intrinsic sex-specific differences. MATERIALS AND METHODS: A total of 22 (11 male [aged 74.5 ± 9.1 years]; 11 female [aged 73.6 ± 12.8 years]) human cadaveric heads with no history of temporomandibular disc derangement underwent cone beam computed tomography and high-resolution magnetic resonance imaging scanning to determine 3-dimensional cephalometric parameters and temporomandibular morphometric outcomes. Regression models between morphometric outcomes and cephalometric parameters were developed, and intrinsic sex-specific differences in temporomandibular morphometry normalized by cephalometric parameters were determined. Subject-specific finite element (FE) models of the extreme male and extreme female conditions were developed to predict variations in articular disc stress-strain under the same joint loading. RESULTS: In some cases, sex differences in temporomandibular morphometric parameters could be explained by linear scaling with skull size and shape; however, scaling alone could not fully account for some differences between sexes, indicating intrinsic sex-specific differences. The intrinsic sex-specific differences in temporomandibular morphometry included an increased condylar medial length and mediolateral disc lengths in men and a longer anteroposterior disc length in women. Considering the extreme male and female temporomandibular morphometry observed in the present study, subject-specific FE models resulted in sex differences, with the extreme male joint having a broadly distributed stress field and peak stress of 5.28 MPa. The extreme female joint had a concentrated stress field and peak stress of 7.37 MPa. CONCLUSIONS: Intrinsic sex-specific differences independent of scaling with donor skull size were identified in temporomandibular morphometry. Understanding intrinsic sex-specific morphometric differences is critical to determining the temporomandibular biomechanics given the effect of anatomy on joint contact mechanics and stress-strain distributions and requires further study as one potential factor for the increased predisposition of women to temporomandibular disc derangement.
Authors: Gregory J Wright; Jonathan Kuo; Changcheng Shi; Thierry R H Bacro; Elizabeth H Slate; Hai Yao Journal: Ann Biomed Eng Date: 2013-06-15 Impact factor: 3.934
Authors: Peter Claes; Jasmien Roosenboom; Julie D White; Tomek Swigut; Dzemila Sero; Jiarui Li; Myoung Keun Lee; Arslan Zaidi; Brooke C Mattern; Corey Liebowitz; Laurel Pearson; Tomás González; Elizabeth J Leslie; Jenna C Carlson; Ekaterina Orlova; Paul Suetens; Dirk Vandermeulen; Eleanor Feingold; Mary L Marazita; John R Shaffer; Joanna Wysocka; Mark D Shriver; Seth M Weinberg Journal: Nat Genet Date: 2018-02-19 Impact factor: 38.330