title: Evaluation of masseter muscle in different vertical skeletal patterns in growing patients.
abstract: OBJECTIVE
  The present study aimed to evaluate the relationship between masseter size, maxillary intermolar width and craniofacial vertical skeletal pattern.
  
  
  METHODS
  
  
  
  METHODS
  The study followed a prospective longitudinal design and enrolled 61 subjects (30 males and 31 females), 9-14 years of age (mean age 11.5) at 2-3 CVM stage. The participants were divided into three groups based on their vertical skeletal pattern which was estimated using the Frankfurt-mandibular plane angle: low-angle group (L-A), normal-angle group (N-A), high-angle group (H-A). An additional gender-based distinction was made. Maxillary intermolar width was measured on the maxillary cast of each patient by means of an electronic caliper; masseter volume was estimated by using magnetic resonance (MR) and masseter thickness was measured by means of ultrasonography (US). The US registrations were performed during the relaxation state (RS) and the maximum voluntary contraction (MVC) of the muscle. The indipendent samples T- test was used for sex comparisons; the analysis of variance test (ANOVA) was used to evaluate the differences between the three groups in males and females, and the Pearson r correlation coefficient was employed to assess the correlation between maxillary intermolar width and masseter volume.
  
  
  CONCLUSIONS
  Maxillary intermolar width, masseter volume and thickness showed significant gender differences; all the tested variables decreased significantly according to the facial vertical pattern, with greater values in females, especially in low- and normal-angle subjects; maxillary intermolar width and masseter volume showed significant correlations, higher in females.
authors.affiliation: Private Practice, Filettole, Pisa, Italy.
authors.forename: K
authors.initials: K
authors.lastname: Biondi
authors.affiliation: Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Lorusso
authors.affiliation: Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Fastuca
authors.affiliation: Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Mangano
authors.affiliation: Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy.
authors.forename: P A
authors.initials: PA
authors.lastname: Zecca
authors.affiliation: Department of Surgical Diagnostic and Pediatric Clinical Sciences, University of Pavia, Pavia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Bosco
authors.affiliation: Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Caprioglio
authors.affiliation: Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Levrini
mesh_terms: D000293:Adolescent; D002508:Cephalometry / Q000379:methods; D002648:Child; D003724:Dental Arch / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008406:Masseter Muscle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008437:Maxilla / Q000033:anatomy & histology*; D003765:Models, Dental; D008963:Molar / Q000033:anatomy & histology; D009119:Muscle Contraction / Q000502:physiology; D009126:Muscle Relaxation / Q000502:physiology; D009929:Organ Size; D011446:Prospective Studies; D012737:Sex Factors; D014463:Ultrasonography; D014716:Vertical Dimension