title: The effects of denervation and formoterol administration on facial growth.
abstract: OBJECTIVE
  To identify and demonstrate possible alterations of skeletal structures which might follow either unilateral surgical denervation of the masseter muscle, unilateral intramuscular injection of formoterol directly into the masseter muscle, or intramuscular formoterol injection after surgical denervation.
  
  
  METHODS
  Male Sprague Dawley rats (N = 16; four weeks of age) were prepared as four groups: 1. surgical sham + saline injection into the masseter muscle (sham); 2. surgical denervation of the masseter muscle only (den.); 3. surgical denervation of the masseter muscle plus intramuscular formoterol injection into the affected muscle (den.+form.); 4. intramuscular formoterol injection into the masseter muscle only (form.). The specimens were submitted for CT examination, the skulls and hemimandibles were photographed and measurements of craniofacial bones were made.
  
  
  RESULTS
  In this relatively small sample, comparisons between non-experimental and experimental sides revealed differences, both within the groups and for the same measurements between groups, with the den. and den.+form. groups showing the most change. Relative increases in the gonial angle shown in these groups occurred bilaterally, with the change on the experimental side always greater in magnitude than the change on the contralateral side.
  
  
  CONCLUSIONS
  Surgical denervation of the masseter muscle leads to an alteration in the size and shape of the skeletal structures close to the zygoma and the mandible. The intramuscular injection of formoterol into denervated masseter muscle seems to limit this skeletal alteration after surgical denervation.
authors.affiliation: University of Melbourne, Oral and Maxillofacial Surgery, Royal Melbourne Hospital, Australia.
authors.forename: Brendan
authors.initials: B
authors.lastname: Fitzpatrick
authors.forename: Michael
authors.initials: M
authors.lastname: Woods
authors.forename: Gordon
authors.initials: G
authors.lastname: Lynch
authors.forename: David
authors.initials: D
authors.lastname: Manton
mesh_terms: D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002508:Cephalometry / Q000379:methods; D004983:Ethanolamines / Q000008:administration & dosage / Q000494:pharmacology*; D000068759:Formoterol Fumarate; D007273:Injections, Intramuscular; D008297:Male; D008334:Mandible / Q000187:drug effects / Q000254:growth & development / Q000473:pathology; D008406:Masseter Muscle / Q000187:drug effects / Q000254:growth & development / Q000294:innervation*; D008437:Maxilla / Q000187:drug effects / Q000254:growth & development / Q000473:pathology; D008445:Maxillofacial Development / Q000187:drug effects / Q000502:physiology*; D009121:Muscle Denervation / Q000379:methods*; D010781:Photography / Q000379:methods; D017207:Rats, Sprague-Dawley; D013701:Temporal Bone / Q000187:drug effects / Q000254:growth & development / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods; D015050:Zygoma / Q000187:drug effects / Q000254:growth & development / Q000473:pathology
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D004983:Ethanolamines; D000068759:Formoterol Fumarate