title: [Fibre-type differences in masseter muscle of Beagle dogs with implanted functional appliance therapy].
abstract: OBJECTIVE
  To observe the changes of MyHC-I expression in masseter muscle of Beagle dogs with implanted functional appliance therapy，and to investigate the adaptive remodeling of masticatory muscle.
  
  
  METHODS
  Eight, seven-month-old, male Beagle dogs were randomly assigned to experimental group and control group and were killed at 4,8,12 weeks during treatment and 4 weeks after the appliance removed(16 weeks). Serial cross-sections of superficial masseter muscle were cut and stained with MyHC-I antibodies.SPSS11.5 software package was used for statistical analysis.
  
  
  RESULTS
  The positive expression rate of MyHC-I was 7.61% in the control group, and 20.43% in the experimental groups at 4 weeks﹙P<0.01﹚. The amount of type I fibres reached to peak at 8 weeks. With increase of treatment time, the amount of type I fibres gradually reduced. At 16 weeks, the amount of type I fibres was similar to the control groups.
  
  
  CONCLUSIONS
  The expression of MyHC-I is significantly changed in masseter muscles of Beagle dogs with implanted functional appliance therapy. Implanted functional appliance forward mandibular displacement therapy can obviously promote the adaptive remodeling of masticatory muscle.
authors.affiliation: Department of Orthodontics，Hangzhou Stomatology Hospital. Hangzhou 310006, China. E-mail:sxr816@163.com.
authors.forename: Xu-rong
authors.initials: XR
authors.lastname: Sun
authors.affiliation: Zhejiang Chinese Medical University. Hangzhou 310016,Zhejiang Province,China.
authors.forename: Xin-ping
authors.initials: XP
authors.lastname: Lin
authors.affiliation: Department of Orthodontics，Hangzhou Stomatology Hospital. Hangzhou 310006, China.
authors.forename: Ya-bo
authors.initials: YB
authors.lastname: Cao
mesh_terms: D000818:Animals; D004285:Dogs; D008297:Male; D008406:Masseter Muscle / Q000033:anatomy & histology*; D008410:Masticatory Muscles; D018995:Myosin Heavy Chains; D017289:Orthodontic Appliances, Functional
chemical_list: D018995:Myosin Heavy Chains