Characterizing mandibular growth using three-dimensional imaging techniques and anatomic landmarks. (May 2017)

• Record Type: Journal Article
• Authors: Kelly, Michael P.; Vorperian, Houri K.; Wang, Yuan; Tillman, Katelyn K.; Werner, Helen M.; Chung, Moo K.; Gentry, Lindell R.
• Is Part Of: Archives of oral biology. Volume 77(2017)
• Page Start: 27
• Page End: 38
• Publication Date: 2017-05
• Subjects: 2D two-dimensional -- 3D three-dimensional -- CDC Centers for Disease Control and Prevention -- CT computed tomorgraphy -- DICOM digital imaging and communications in medicine -- GE general electric -- HU Hounsfield units -- IRB Institutional Review Board -- NIH National Institutes of Health -- NIDCD National Institute on Deafness and Other Communication Disorders -- NICHD National Institute of Child Health and Human Development -- WHO World Health Organization; Mandible -- Development -- Measurement -- 3DCT; Mouth -- Periodicals; Mouth -- Diseases -- Periodicals; Dentistry -- Periodicals; Electronic journals; 617.6005
• DOI: 10.1016/j.archoralbio.2017.01.018
• Languages: English
• ISSNs: 0003-9969

Abstract

Highlights: Mandibular growth trend and growth rate is non uniform and sex specific. Growth in the horizontal plane is mostly neural, and vertical growth mostly somatic. Around ages eight to ten years, growth in males begins to outpace that of females. Sex differences, evident early, are mostly in the inferior portion of the mandible. Findings can be used as normative data on mandibular growth for clinical assessment. Abstract: Objective: To provide quantitative data on the multi-planar growth of the mandible, this study derived accurate linear and angular mandible measurements using landmarks on three dimensional (3D) mandible models. This novel method was used to quantify 3D mandibular growth and characterize the emergence of sexual dimorphism. Design: Cross-sectional and longitudinal imaging data were obtained from a retrospective computed tomography (CT) database for 51 typically developing individuals between the ages of one and nineteen years. The software Analyze was used to generate 104 3DCT mandible models. Eleven landmarks placed on the models defined six linear measurements (lateral condyle, gonion, and endomolare width, ramus and mental depth, and mandible length) and three angular measurements (gonion, gnathion, and lingual). A fourth degree polynomial fit quantified growth trends, its derivative quantified growth rates, and a composite growth model determined growth types (neural/cranial and somatic/skeletal). Sex differences were assessed in four age cohorts, each spanning five years, to determine the ontogenetic pattern producing sexual dimorphism of the adult mandible. Results: Mandibular growth trends and growth rates were non-uniform. In general, structures in the horizontal plane displayed predominantly neural/cranial growth types, whereas structures in the vertical plane had somatic/skeletal growth types. Significant prepubertal sex differences in the inferior aspect of the mandible dissipated when growth in males began to outpace that of females at eight to ten years of age, but sexual dimorphism re-emerged during and after puberty. Conclusions: This 3D analysis of mandibular growth provides preliminary normative developmental data for clinical assessment and craniofacial growth studies.