title: A method for measuring the structural properties of the rat mandible.
abstract: The rat mandible has been used to study fractures, ridge augmentation, bone defects, and the effects of cryosurgery, all of which affect the structural properties of the mandible. The only previously described mechanical test of the rat mandible used three-point bending with a piece of foam placed between the lingual surface of the mandible and the support. The accuracy and reproducibility of this test were not determined. Two different, three-point bending tests for characterizing the structural properties of the rat mandible have now been evaluated. Acrylic specimens representing three different-sized mandibles were tested in three-point bending with either potted ends or foam interposed between the specimen and the outer load points. Flexural stiffness and failure load were compared against data from a conventional three-point bending test. In addition, five paired halves of 90- and 210-day-old rat mandibles were tested either with interposed foam or with potted ends and the mean coefficients of variation of the stiffness and failure loads were determined. Failure loads of the acrylic specimens with the potted and foam methods were significantly higher (50 and 10%, respectively; p < 0.05) than with the conventional method. The stiffness of the acrylic specimens with the potted and foam methods was significantly different (75% higher and 21% lower, respectively; p < 0.05) than with the conventional test. In addition, there was no difference between the coefficient of variation in stiffness (26 + 11%) or failure load (10 + 4%) measured with the foam test and the comparable values (16 + 11%) and (18 + 13%) in the potted test.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Orthopedic Biomechanics Lab., Beth Israel Hospital, Boston, MA 02215, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Elovic
authors.forename: J A
authors.initials: JA
authors.lastname: Hipp
authors.forename: W C
authors.initials: WC
authors.lastname: Hayes
mesh_terms: D000180:Acrylic Resins; D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D003799:Dental Stress Analysis / Q000295:instrumentation / Q000379:methods*; D004195:Disease Models, Animal; D004548:Elasticity; D008334:Mandible / Q000502:physiology*; D051381:Rats; D015203:Reproducibility of Results; D014622:Vaginal Creams, Foams, and Jellies; D016474:Weight-Bearing
chemical_list: D000180:Acrylic Resins; D014622:Vaginal Creams, Foams, and Jellies