International Journal of Oral & Maxillofacial Surgery
Volume 39, Issue 6 , Pages 593-598, June 2010

The influence of masticatory hypofunction on developing rat craniofacial structure☆

  • C.Y. Tsai

      Affiliations

    • Graduate Institute of Dentistry, College of Oral Medicine, Taipei Medical University and Hospital, Taipei, Taiwan, ROC
    • Corresponding Author InformationAddress: Chi Yang Tsai, No. 250 Wu-Hsing Street, Taipei 11042, Taiwan, ROC. Tel.: +886 2 27361661x5139; fax: +886 2 27362295/87739467.
    • ,
  • L.Y. Yang

      Affiliations

    • Department of Physiology, College of Medicine, Taipei Medical University, Taipei, Taiwan, ROC
    • ,
  • K.T. Chen

      Affiliations

    • Craniofacial Center, Chang-Gung Memorial Hospital, Taipei, Taiwan, ROC
    • Chang-Gung University, College of Medicine, Linkou, Taiwan, ROC
    • ,
  • W.C. Chiu

      Affiliations

    • Graduate Institute of Dentistry, College of Oral Medicine, Taipei Medical University and Hospital, Taipei, Taiwan, ROC
    • Department of Orthodontics, Cardinal Tien Hospital Yung Ho Branch, Taiwan, ROC

Accepted 5 February 2010. published online 11 March 2010.

Abstract 

The purpose of this study was to use botulinum neurotoxin type A (BoNT/A) selectively to evaluate the influence of localized masticatory atrophy and paresis on craniofacial growth and development. 60 growing rats, 4 weeks old, weighing approximately 120g, were randomly divided according as follows (Long-Evans, N=15 per group): I (Mb+Tns); II (Mns+Tb); III (Mb+Tb); IV (Mns+Tns), where Mb or Tb is the BoNT/A-injected masseter or temporalis muscles (1.0U/muscle, 2.5ml) and Mns or Tns is the saline-injected muscles (2.5ml). After 7 weeks, the mature rats were killed, the muscles dissected and mean muscle mass recorded. Anthropometric cranial, maxillary and mandibular measurements were taken from the dried skulls. Changes in animal weight during the growth period were not statistically significant. The mean masticatory muscle mass was smaller for the BoNT/A-injected muscles of Mb and Tb. Anthropometric measurements of bony structures inserted by masseter and temporalis muscles revealed a significant treatment effect. The measurements showed a facial morphology typical of a dolichofacial profile: short upper face accompanied by a long lower face with an extended mandibular length and ramus height and constricted bicoronoidal and bigonial widths. The results suggest that induction of localized masticatory muscle atrophy with BoNT/A alters craniofacial growth and development.

Key words: botulinum neurotoxin, masseter muscle, temporalis muscle, masticatory muscle atrophy, craniofacial growth and development

To access this article, please choose from the options below

Login to an existing account or Register a new account.

  • Purchase this article for 31.50 USD (You must login/register to purchase this article)

    Online access for 24 hours. The PDF version can be downloaded as your permanent record.

  • Subscribe to this title

    Get unlimited online access to this article and all other articles in this title 24/7 for one year.

  • Claim access now

    For current subscribers with Society Membership or Account Number.

  • Visit SciVerse ScienceDirect to see if you have access via your institution.
 

☆ This research is based on a thesis submitted to the graduate faculty of College of Oral Medicine, Taipei Medical University, in fulfillment of the requirements for the M.S. degree by Wan Chi Chiu.

PII: S0901-5027(10)00054-8

doi:10.1016/j.ijom.2010.02.011

International Journal of Oral & Maxillofacial Surgery
Volume 39, Issue 6 , Pages 593-598, June 2010

Article Tools

* Image Usage & Resolution