To test the hypotheses that mechanobehavior scores (MBS) were correlated with mandibular ramus lengths (Co-Go) and differed between facial phenotypes.
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 × DF,) for each TMJ. Polynomial regressions, K-means cluster analysis, and analysis of variance (ANOVA) with Tukey post-hoc tests were employed.
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 ± 5.9°) compared to the brachyfacial group (29.8 ± 5.5°).
MBS correlated with Co-Go within sexes and differed significantly between brachyfacial and dolichofacial subjects.
Private Practice, Leawood, Kansas, USA.
Professor-Provisional, Department of Orthodontics, School of Dentistry, Oregon Health & Science University, Portland, Oregon, USA; and Research Associate Professor, Department of Oral Diagnostic Sciences, University at Buffalo, School of Dental Medicine, Buffalo, New York, USA.
Assistant Professor, Department of Biostatistics and Epidemiology, College of Public Health, East Tennessee State University, Johnson City, Tennessee, USA.
Associate Professor, Department of Oral Diagnostic Sciences, University at Buffalo, School of Dental Medicine, Buffalo, New York, USA.
Professor, Physiology and Biomechanics of the Masticatory System, Dental School, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
Private Practice, Washington, Pennsylvania, USA.
Statistician, University of Buffalo Microbiome Center, School of Dental Medicine, Buffalo, New York, USA.
Senior Research Associate, Department of Orthodontics, School of Dentistry, Oregon Health & Science University, Portland, Oregon, USA.