Mechanobehavior and mandibular ramus length in different facial phenotypes

Paige Covington Riddle, Jeffrey C. Nickel, Ying Liu, Yoly M. Gonzalez, Luigi M. Gallo, R. Scott Conley, Robert Dunford, Hongzeng Liu, Laura R. Iwasaki

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Objectives: To test the hypotheses that mechanobehavior scores (MBS) were correlated with mandibular ramus lengths (Co-Go) and differed between facial phenotypes. Materials and Methods: Subjects gave informed consent to participate. Co-Go (mm), mandibular plane angles (SN-GoGn, °), and three-dimensional anatomy were derived from cephalometric radiography or cone beam computed tomography. Temporomandibular joint (TMJ) energy densities (ED) (mJ/mm3) were measured using dynamic stereometry and duty factors (DF) (%) were measured from electromyography, to calculate MBS (= ED2 3 DF, (mmmJ3)2%) for each TMJ. Polynomial regressions, K-means cluster analysis, and analysis of variance (ANOVA) with Tukey post-hoc tests were employed. Results: Fifty females and 23 males produced replete data. Polynomial regressions showed MBS were correlated with Co-Go (females, R2 = 0.57; males, R2 = 0.81). Cluster analysis identified three groups (P<.001). Dolichofacial subjects, with shorter normalized Co-Go, clustered into two subgroups with low and high MBS compared to brachyfacial subjects with longer Co-Go. SN-GoGn was significantly larger (P<.03) in the dolichofacial subgroups combined (33.0 ± 5.98) compared to the brachyfacial group (29.8 ± 5.58). Conclusions: MBS correlated with Co-Go within sexes and differed significantly between brachyfacial and dolichofacial subjects.

Original languageEnglish (US)
Pages (from-to)866-872
Number of pages7
JournalAngle Orthodontist
Issue number6
StatePublished - Nov 2020


  • Craniofacial form
  • EMG
  • Human
  • Jaw mechanics
  • Masticatory muscles
  • TMJ

ASJC Scopus subject areas

  • Orthodontics


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