title: Loading effects on rat craniomandibular morphology: a system for gravity studies.
abstract: Gravity effects on muscle and bone are a major impediment to long-term space travel. We introduce a model for studying these effects, the craniomandibular system. Some advantages of this system include: (1) craniomandibular morphology is determined by epigenetic factors including gravity, (2) relatively light forces can significantly alter its morphology, and (3) soft diet and tooth loss produce effects that are similar to those produced in lower limbs by weightlessness. In the study, implants made either of gold (experimental group) or lightweight acrylic (controls) were attached to adult rats' mandibles. After 13 weeks, the animals' skulls and mandibles were dissected. Pair-wise comparisons indicated that the experimental animals showed significantly shortened and narrowed cranial bases, and significant changes in the posterior zygomatic arch region. These results indicate that simulated macrogravity influences bone remodeling in the adult craniomandibular system.
authors.affiliation: Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA.
authors.forename: Ranbir
authors.initials: R
authors.lastname: Singh
authors.forename: Thais
authors.initials: T
authors.lastname: Carvalho
authors.forename: Geoffrey E
authors.initials: GE
authors.lastname: Gerstner
mesh_terms: D000180:Acrylic Resins; D000818:Animals; D001846:Bone Development / Q000502:physiology*; D002508:Cephalometry; D015921:Dental Implants / Q000009:adverse effects*; D003764:Dental Materials; D006046:Gold; D006112:Gravitation; D008297:Male; D008334:Mandible / Q000033:anatomy & histology*; D008410:Masticatory Muscles / Q000033:anatomy & histology*; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000033:anatomy & histology*
chemical_list: D000180:Acrylic Resins; D015921:Dental Implants; D003764:Dental Materials; D006046:Gold