title: Comparison of clinical marking and ultrasound-guided injection of Botulinum type A toxin into the masseter muscles for treating bruxism and its cosmetic effects.
abstract: BACKGROUND
  Botulinum toxin type A has been used for treating the hypertrophy of the masseter muscles and its cosmetic effects. Ultrasound is increasingly used in dermatology, along with the guidance of mini-invasive procedures.
  
  
  OBJECTIVE
  To evaluate the role of ultrasound for guiding the application of Botulinum A toxin in patients with cosmetic alterations due to bruxism, correlate the clinical landmarks with the ultrasound findings, and study the effect on the symptoms, cosmetics, and quality of life.
  
  
  METHODS
  Twenty individuals with bruxism and cosmetic alterations underwent an ultrasound-guided injection of Botulinum toxin type A in each masseter muscle. Clinical and ultrasound marking of the procedure was compared. Clinical and sonographic evaluation was performed at the time of injection and 3 months later. Ten normal individuals underwent ultrasound of the masseter muscles as a control group.
  
  
  RESULTS
  Up to 65% of individuals showed anatomical variants of the salivary glands. The method for clinically marking the skin showed a frequently erroneous location of the anterior point (up to 40% of cases) that was proven by ultrasound to be out of the muscle. In 20% of cases, ultrasound showed that the needle should be longer to enter the muscle. After injection, most of the patients demonstrated a decrease of the symptoms and cosmetic and quality of life improvements.
  
  
  CONCLUSIONS
  Ultrasound can be a potent tool for guiding the injection of Botulinum toxin into the masseter muscles. It may contribute to a more personalized procedure, better cosmetic results, and help to avoid potential complications.
authors.affiliation: Department of Dermatology, Faculty of Medicine, Pontifical Catholic University, Santiago, Chile.
authors.forename: Natacha
authors.initials: N
authors.lastname: Quezada-Gaon
authors.affiliation: Department of Radiology and Department of Dermatology, Institute for Diagnostic Imaging and Research of the Skin and Soft Tissues, Clinica Servet, Faculty of Medicine, University of Chile, Santiago, Chile.
authors.forename: Ximena
authors.initials: X
authors.lastname: Wortsman
authors.affiliation: Department of Dentistry, University Pedro de Valdivia, Santiago, Chile.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Peñaloza
authors.affiliation: Department of Dermatology, Faculty of Medicine, Pontifical Catholic University, Santiago, Chile.
authors.forename: Juan Eduardo
authors.initials: JE
authors.lastname: Carrasco
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D002012:Bruxism / Q000150:complications / Q000188:drug therapy*; D016022:Case-Control Studies; D004954:Esthetics; D005145:Face / Q000473:pathology; D005260:Female; D006801:Humans; D006984:Hypertrophy / Q000150:complications; D007273:Injections, Intramuscular; D008297:Male; D008406:Masseter Muscle / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D011446:Prospective Studies; D011788:Quality of Life; D018608:Ultrasonography, Doppler; D018084:Ultrasonography, Interventional
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A
keywords: botulinum toxin; botulinum toxin ultrasound; bruxism; cosmetic procedures; cosmetic ultrasound; dermatologic ultrasound; skin imaging; skin ultrasound; ultrasound; ultrasound dermatology